title: Montreal

text: Some of the city's earliest still-standing buildings date back to the late 17th and early 18th centuries. Although most are clustered around the Old Montreal area, such as the Sulpician Seminary adjacent to Notre Dame Basilica that dates back to 1687, and Château Ramezay, which was built in 1705, examples of early colonial architecture are dotted throughout the city. Situated in Lachine, the Le Ber-Le Moyne House is the oldest complete building in the city, built between 1669 and 1671. In Point St. Charles visitors can see the Maison Saint-Gabriel, which can trace its history back to 1698. There are many historic buildings in Old Montreal in their original form: Notre Dame of Montreal Basilica, Bonsecours Market, and the 19th‑century headquarters of all major Canadian banks on St. James Street (French: Rue Saint Jacques). Montreal's earliest buildings are characterized by their uniquely French influence and grey stone construction.


title: Montreal

text: Saint Joseph's Oratory, completed in 1967, Ernest Cormier's Art Deco Université de Montréal main building, the landmark Place Ville Marie office tower, the controversial Olympic Stadium and surrounding structures, are but a few notable examples of the city's 20th-century architecture. Pavilions designed for the 1967 International and Universal Exposition, popularly known as Expo 67, featured a wide range of architectural designs. Though most pavilions were temporary structures, several have become landmarks, including Buckminster Fuller's geodesic dome U.S. Pavilion, now the Montreal Biosphere, and Moshe Safdie's striking Habitat 67 apartment complex.


title: Montreal

text: In 2006 Montreal was named a UNESCO City of Design, one of only three design capitals of the world (the others being Berlin and Buenos Aires). This distinguished title recognizes Montreal's design community. Since 2005 the city has been home for the International Council of Graphic Design Associations (Icograda); the International Design Alliance (IDA).


title: Montreal

text: The Underground City (officially RESO) is an important tourist attraction. It is the set of interconnected shopping complexes (both above and below ground). This impressive network connects pedestrian thoroughfares to universities, as well as hotels, restaurants, bistros, subway stations and more, in and around downtown with of tunnels over of the most densely populated part of Montreal.


title: Montreal

text: Côte-des-Neiges–Notre-Dame-de-Grace, The Plateau Mount Royal, Outremont and Ville Marie in the centre; Mercier–Hochelaga-Maisonneuve, Rosemont–La Petite-Patrie and Villeray–Saint-Michel–Parc-Extension in the east; Anjou, Montréal-Nord, Rivière-des-Prairies–Pointe-aux-Trembles and Saint-Leonard in the northeast; Ahuntsic-Cartierville, L'Île-Bizard–Sainte-Geneviève, Pierrefonds-Roxboro and Saint-Laurent in the northwest; and Lachine, LaSalle, The South West and Verdun in the south.


title: Montreal

text: Many of these boroughs were independent cities that were forced to be merged with Montreal in January 2002 following the 2002 municipal reorganization of Montreal.


title: Montreal

text: The borough with the most neighbourhoods is Ville Marie, which includes downtown, the historical district of Old Montreal, Chinatown, the Gay Village, the Latin Quarter, the gentrified Quartier international and Cité Multimédia as well as the Quartier des Spectacles which is under development. Other neighbourhoods of interest in the borough include the affluent Golden Square Mile neighbourhood at the foot of Mount Royal and the Shaughnessy Village/Concordia U area home to thousands of students at Concordia University. The borough also comprises most of Mount Royal Park, Saint Helen's Island, and Notre-Dame Island.


title: Montreal

text: The Plateau Mount Royal borough was a working class francophone area. The largest neighbourhood is the Plateau (not to be confused with the whole borough), which is undergoing considerable gentrification, and a 2001 study deemed it as Canada's most creative neighbourhood because artists comprise 8% of its labour force. The neighbourhood of Mile End in the northwestern part of the borough has been a very multicultural area of the city, and features two of Montreal's well-known bagel establishments, St-Viateur Bagel and Fairmount Bagel. The McGill Ghetto is in the extreme southwestern portion of the borough, its name being derived from the fact that it is home to thousands of McGill University students and faculty members.


title: Montreal

text: The South West borough was home to much of the city's industry during the late 19th and early-to-mid 20th century. The borough included Goose Village and was historically home to the traditionally working-class Irish neighbourhoods of Griffintown and Point Saint Charles as well as the low-income neighbourhoods of Saint Henri and Little Burgundy.


title: Montreal

text: Other notable neighbourhoods include the multicultural areas of Notre-Dame-de-Grâce and Côte-des-Neiges in the Côte-des-Neiges–Notre-Dame-de-Grace borough, and Little Italy in the borough of Rosemont–La Petite-Patrie and Hochelaga-Maisonneuve, home of the Olympic Stadium in the borough of Mercier–Hochelaga-Maisonneuve.


title: Montreal

text: Old Montreal is a historic area southeast of downtown containing many attractions such as the Old Port of Montreal, Place Jacques-Cartier, Montreal City Hall, the Bonsecours Market, Place d'Armes, Pointe-à-Callière Museum, the Notre-Dame de Montréal Basilica, and the Montreal Science Centre.


title: Montreal

text: Architecture and cobbled streets in Old Montreal have been maintained or restored. Old Montreal is accessible from the downtown core via the underground city and is served by several STM bus routes and Metro stations, ferries to the South Shore and a network of bicycle paths.


title: Montreal

text: The riverside area adjacent to Old Montreal is known as the Old Port. The Old Port was the site of the Port of Montreal, but its shipping operations have been moved to a larger site downstream, leaving the former location as a recreational and historical area maintained by Parks Canada. The new Port of Montreal is Canada's largest container port and the largest inland port on Earth.


title: Montreal

text: The mountain is the site of Mount Royal Park, one of Montreal's largest greenspaces. The park, most of which is wooded, was designed by Frederick Law Olmsted, who also designed New York's Central Park, and was inaugurated in 1876.


title: Montreal

text: The park contains two belvederes, the more prominent of which is the Kondiaronk Belvedere, a semicircular plaza with a chalet overlooking Downtown Montreal. Other features of the park are Beaver Lake, a small man-made lake, a short ski slope, a sculpture garden, Smith House, an interpretive centre, and a well-known monument to Sir George-Étienne Cartier. The park hosts athletic, tourist and cultural activities.


title: Montreal

text: The mountain is home to two major cemeteries, Notre-Dame-des-Neiges (founded in 1854) and Mount Royal (1852). Mount Royal Cemetery is a terraced cemetery on the north slope of Mount Royal in the borough of Outremont. Notre Dame des Neiges Cemetery is much larger, predominantly French-Canadian and officially Catholic. More than 900,000 people are buried there.


title: Montreal

text: Mount Royal Cemetery contains more than 162,000 graves and is the final resting place for a number of notable Canadians. It includes a veterans section with several soldiers who were awarded the British Empire's highest military honour, the Victoria Cross. In 1901, the Mount Royal Cemetery Company established the first crematorium in Canada.


title: Montreal

text: The first cross on the mountain was placed there in 1643 by Paul Chomedey de Maisonneuve, the founder of the city, in fulfilment of a vow he made to the Virgin Mary when praying to her to stop a disastrous flood. Today, the mountain is crowned by a 31.4 m-high (103 ft) illuminated cross, installed in 1924 by the John the Baptist Society and now owned by the city. It was converted to fibre optic light in 1992. The new system can turn the lights red, blue, or purple, the last of which is used as a sign of mourning between the death of the Pope and the election of the next.


title: Montreal

text: In the 2021 Census of Population conducted by Statistics Canada, Montréal had a population of living in of its total private dwellings, a change of from its 2016 population of . With a land area of , it had a population density of in 2021.


title: Montreal

text: According to Statistics Canada, at the 2016 Canadian census the city had 1,704,694 inhabitants. A total of 4,098,927 lived in the Montreal Census Metropolitan Area (CMA) at the same 2016 census, up from 3,934,078 at the 2011 census (within 2011 CMA boundaries), which is a population growth of 4.19% from 2011 to 2016. In 2015, the Greater Montreal population was estimated at 4,060,700. According to StatsCan, by 2030, the Greater Montreal Area is expected to number 5,275,000 with 1,722,000 being visible minorities.


title: Montreal

text: In the 2016 census, children under 14 years of age (691,345) constituted 16.9%, while inhabitants over 65 years of age (671,690) numbered 16.4% of the total population of the CMA.


title: Montreal

text: People of European ethnicities formed the largest cluster of ethnic groups. The largest reported European ethnicities in the 2006 census were French 23%, Italians 10%, Irish 5%, English 4%, Scottish 3%, and Spanish 2%.


title: Montreal

text: Some 26% of the population of Montreal and 16.5% that of Greater Montreal, are members of a visible minority (non-white) group, up from 5.2% in 1981.


title: Montreal

text: Visible minorities comprised 34.2% of the population in the 2016 census. The five most numerous visible minorities are Black Canadians (10.3%), Arab Canadians (7.3%), Latin Americans (4.1%), South Asian Canadian (3.3%), and Chinese Canadians (3.3%). Visible minorities are defined by the Canadian Employment Equity Act as "persons, other than Aboriginals, who are non-white in colour".


title: Montreal

text: In terms of mother language (first language learned), the 2006 census reported that in the Greater Montreal Area, 66.5% spoke French as a first language, followed by English at 13.2%, while 0.8% spoke both as a first language. The remaining 22.5% of Montreal-area residents are allophones, speaking languages including Italian (3.5%), Arabic (3.1%), Spanish (2.6%), Creole (1.3%), Chinese (1.2%), Greek (1.2%), Portuguese (0.8%), Berber language (0.8%), Romanian (0.7%), Vietnamese (0.7%), and Russian (0.7%). In terms of additional languages spoken, a unique feature of Montreal among Canadian cities, noted by Statistics Canada, is the working knowledge of both French and English possessed by most of its residents.


title: Montreal

text: The 2021 census reported that immigrants (individuals born outside Canada) comprise 576,125 persons or 33.4% of the total population of Montreal. Of the total immigrant population, the top countries of origin were Haiti (47,550 persons or 8.3%), Algeria (43,840 persons or 7.6%), France (39,275 persons or 6.8%), Morocco (33,005 persons or 5.7%), Italy (30,215 persons or 5.2%), China (26,335 persons or 4.6%), Philippines (20,475 persons or 3.6%), Lebanon (17,455 persons or 3.0%), Vietnam (16,395 persons or 2.8%), and India (13,575 persons or 2.4%).


title: Montreal

text: The Greater Montreal Area is predominantly Catholic; however, weekly attendance in Quebec was among the lowest in Canada in 1998. Historically Montreal has been a centre of Catholicism in North America with its numerous seminaries and churches, including the Notre-Dame Basilica, the Cathédrale Marie-Reine-du-Monde, and Saint Joseph's Oratory.


title: Montreal

text: Some 49.5% of the total population is Christian, largely Roman Catholic (35.0%), primarily because of descendants of original French settlers, and others of Italian and Irish origins. Protestants which include Anglican Church in Canada, United Church of Canada, Lutheran, owing to British and German immigration, and other denominations number 11.3%, with a further 3.2% consisting mostly of Orthodox Christians, fuelled by a large Greek population. There is also a number of Russian and Ukrainian Orthodox parishes.


title: Montreal

text: Islam is the largest non-Christian religious group, with 218,395 members, the second-largest concentration of Muslims in Canada at 12.7%. The Jewish community in Montreal has a population of 35,930. In cities such as Côte Saint-Luc and Hampstead, Jewish people constitute the majority, or a substantial part of the population. As recently as 1971 the Jewish community in Greater Montreal was as high as 109,480. Political and economic uncertainties led many to leave Montreal and the province of Quebec.


title: Montreal

text: Montreal has the second-largest economy of Canadian cities based on GDP and the largest in Quebec. In 2014, Metropolitan Montreal was responsible for of Quebec's GDP. The city is today an important centre of commerce, finance, industry, technology, culture, world affairs and is the headquarters of the Montreal Exchange. In recent decades, the city was widely seen as weaker than that of Toronto and other major Canadian cities, but it has recently experienced a revival.


title: Montreal

text: Industries include aerospace, electronic goods, pharmaceuticals, printed goods, software engineering, telecommunications, textile and apparel manufacturing, tobacco, petrochemicals, and transportation. The service sector is also strong and includes civil, mechanical and process engineering, finance, higher education, and research and development. In 2002, Montreal was the fourth-largest centre in North America in terms of aerospace jobs.


title: Montreal

text: The Port of Montreal is one of the largest inland ports in the world handling 26 million tonnes of cargo annually. As one of the most important ports in Canada, it remains a transshipment point for grain, sugar, petroleum products, machinery, and consumer goods. For this reason, Montreal is the railway hub of Canada and has always been an extremely important rail city; it is home to the headquarters of the Canadian National Railway, and was home to the headquarters of the Canadian Pacific Railway until 1995.


title: Montreal

text: The headquarters of the Canadian Space Agency is in Longueuil, southeast of Montreal. Montreal also hosts the headquarters of the International Civil Aviation Organization (ICAO, a United Nations body); the World Anti-Doping Agency (an Olympic body); the Airports Council International (the association of the world's airports – ACI World); the International Air Transport Association (IATA), IATA Operational Safety Audit and the International Gay and Lesbian Chamber of Commerce (IGLCC), as well as some other international organizations in various fields.


title: Montreal

text: Montreal is a centre of film and television production. The headquarters of Alliance Films and five studios of the Academy Award-winning documentary producer National Film Board of Canada are in the city, as well as the head offices of Telefilm Canada, the national feature-length film and television funding agency and Télévision de Radio-Canada. Given its eclectic architecture and broad availability of film services and crew members, Montreal is a popular filming location for feature-length films, and sometimes stands in for European locations. The city is also home to many recognized cultural, film and music festivals (Just For Laughs, Just For Laughs Gags, Montreal International Jazz Festival, and others), which contribute significantly to its economy. It is also home to one of the world's largest cultural enterprises, the Cirque du Soleil.


title: Montreal

text: Montreal is also a global hub for artificial intelligence research with many companies involved in this sector, such as Facebook AI Research (FAIR), Microsoft Research, Google Brain, DeepMind, Samsung Research and Thales Group (cortAIx). The city is also home to Mila (research institute), an artificial intelligence research institute with over 500 researchers specializing in the field of deep learning, the largest of its kind in the world.


title: Montreal

text: The video game industry has been booming in Montreal since November 2, 1995, coinciding with the opening of Ubisoft Montreal. Recently, the city has attracted world leading game developers and publishers studios such as EA, Eidos Interactive, BioWare, Artificial Mind and Movement, Strategy First, THQ, Gameloft mainly because of the quality of local specialized labour, and tax credits offered to the corporations. Recently, Warner Bros. Interactive Entertainment, a division of Warner Bros., announced that it would open a video game studio. Relatively new to the video game industry, it will be Warner Bros. first studio opened, not purchased, and will develop games for such Warner Bros. franchises as Batman and other games from their DC Comics portfolio. The studio will create 300 jobs.


title: Montreal

text: Montreal plays an important role in the finance industry. The sector employs approximately 100,000 people in the Greater Montreal Area. As of March 2018, Montreal is ranked in the 12th position in the Global Financial Centres Index, a ranking of the competitiveness of financial centres around the world. The city is home to the Montreal Exchange, the oldest stock exchange in Canada and the only financial derivatives exchange in the country. The corporate headquarters of the Bank of Montreal and Royal Bank of Canada, two of the biggest banks in Canada, were in Montreal. While both banks moved their headquarters to Toronto, Ontario, their legal corporate offices remain in Montreal. The city is home to head offices of two smaller banks, National Bank of Canada and Laurentian Bank of Canada. The Caisse de dépôt et placement du Québec, an institutional investor managing assets totalling $248 billion CAD, has its main business office in Montreal. Many foreign subsidiaries operating in the financial sector also have offices in Montreal, including HSBC, Aon, Société Générale, BNP Paribas and AXA.


title: Montreal

text: Several companies are headquartered in Greater Montreal Area including Rio Tinto Alcan, Bombardier Inc., Canadian National Railway, CGI Group, Air Canada, Air Transat, CAE, Saputo, Cirque du Soleil, Stingray Group, Quebecor, Ultramar, Kruger Inc., Jean Coutu Group, Uniprix, Proxim, Domtar, Le Château, Power Corporation, Cellcom Communications, Bell Canada. Standard Life, Hydro-Québec, AbitibiBowater, Pratt and Whitney Canada, Molson, Tembec, Canada Steamship Lines, Fednav, Alimentation Couche-Tard, SNC-Lavalin, MEGA Brands, Aeroplan, Agropur, Metro Inc., Laurentian Bank of Canada, National Bank of Canada, Transat A.T., Via Rail, GardaWorld, Novacam Technologies, SOLABS, Dollarama, Rona and the Caisse de dépôt et placement du Québec.


title: Montreal

text: The Montreal Oil Refining Centre is the largest refining centre in Canada, with companies like Petro-Canada, Ultramar, Gulf Oil, Petromont, Ashland Canada, Parachem Petrochemical, Coastal Petrochemical, Interquisa (Cepsa) Petrochemical, Nova Chemicals, and more. Shell decided to close the refining centre in 2010, throwing hundreds out of work and causing an increased dependence on foreign refineries for eastern Canada.


title: Montreal

text: Montreal was referred to as "Canada's Cultural Capital" by "Monocle" magazine. The city is Canada's centre for French-language television productions, radio, theatre, film, multimedia, and print publishing. Montreal's many cultural communities have given it a distinct local culture. Montreal was designated as the World Book Capital for the year 2005 by UNESCO.


title: Montreal

text: Being at the confluence of the French and the English traditions, Montreal has developed a unique and distinguished cultural face. The city has produced much talent in the fields of visual arts, theatre, dance, and music, with a tradition of producing both jazz and rock music. Another distinctive characteristic of cultural life is the vibrancy of its downtown, particularly during summer, prompted by cultural and social events, including its more than 100 annual festivals, the largest being the Montreal International Jazz Festival which is the largest jazz festival in the world. Other popular events include the Just for Laughs (largest comedy festival in the world), Montreal World Film Festival, Les FrancoFolies de Montréal, , Pop Montreal, Divers/Cité, Fierté Montréal and the Montreal Fireworks Festival, and many smaller festivals. The city of Montreal is also widely recognized for its diverse and vibrant night life, which is considered a vital part of the local cultural ecosystem.


title: Montreal

text: A cultural heart of classical art and the venue for many summer festivals, the Place des Arts is a complex of different concert and theatre halls surrounding a large square in the eastern portion of downtown. Place des Arts has the headquarters of one of the world's foremost orchestras, the Montreal Symphony Orchestra. The Orchestre Métropolitain du Grand Montréal and the chamber orchestra I Musici de Montréal are two other well-regarded Montreal orchestras. Also performing at Place des Arts are the Opéra de Montréal and the city's chief ballet company Les Grands Ballets Canadiens. Internationally recognized avant-garde dance troupes such as , La La La Human Steps, , and the have toured the world and worked with international popular artists on videos and concerts. The unique choreography of these troupes has paved the way for the success of the world-renowned Cirque du Soleil.


title: Montreal

text: Nicknamed "" (the city of a hundred steeples), Montreal is renowned for its churches. There are an estimated 650 churches on the island, with 450 of them dating back to the 1800s or earlier. Mark Twain noted, "This is the first time I was ever in a city where you couldn't throw a brick without breaking a church window." The city has four Roman Catholic basilicas: Mary, Queen of the World Cathedral, Notre-Dame Basilica, St Patrick's Basilica, and Saint Joseph's Oratory. The Oratory is the largest church in Canada, with the second largest copper dome in the world, after Saint Peter's Basilica in Rome.


title: Montreal

text: Beginning in the 1940s, Quebec literature began to shift from pastoral tales romanticising the French-Canadian country-side to writing set in the multicultural city of Montreal. Notable pioneering works describing the character of the city include Gabrielle Roy's 1945 novel "Bonheur D'Occasion", translated as "The Tin Flute", and Gwethalyn Graham's 1944 novel "Earth and High Heaven". Subsequent writers of fiction who have set their work in Montreal have included Mordecai Richler, Claude Jasmin, Francine Noel, and Heather O'Neill, among many others.


title: Montreal

text: The most popular sport is ice hockey. The professional hockey team, the Montreal Canadiens, is one of the Original Six teams of the National Hockey League (NHL), and has won an NHL-record 24 Stanley Cup championships. The Canadiens' most recent Stanley Cup victory came in 1993. They have major rivalries with the Toronto Maple Leafs and Boston Bruins, both of which are also Original Six teams, and with the Ottawa Senators, the closest team geographically. The Canadiens have played at the Bell Centre since 1996. Prior to that they played at the Montreal Forum.


title: Montreal

text: The Montreal Alouettes of the Canadian Football League (CFL) play at Molson Stadium on the campus of McGill University for their regular-season games. Late season and playoff games are played at the much larger, enclosed Olympic Stadium, which also hosted the 2008 Grey Cup. The Alouettes have won the Grey Cup seven times, most recently in 2010. The Alouettes has had two periods on hiatus. During the second one, the Montreal Machine played in the World League of American Football in 1991 and 1992. The McGill Redbirds, Concordia Stingers, and Université de Montréal Carabins play in the U Sports football league.


title: Montreal

text: Montreal has a storied baseball history. The city was the home of the minor-league Montreal Royals of the International League until 1960. In 1946 Jackie Robinson broke the Baseball colour line with the Royals in an emotionally difficult year; Robinson was forever grateful for the local fans' fervent support. Major League Baseball came to town in the form of the Montreal Expos in 1969. They played their games at Jarry Park Stadium until moving into Olympic Stadium in 1977. After 36 years in Montreal, the team relocated to Washington, D.C., in 2005 and re-branded themselves as the Washington Nationals.


title: Montreal

text: CF Montréal (formerly known as the Montreal Impact) are the city's professional soccer team. They play at a soccer-specific stadium called Saputo Stadium. They joined North America's biggest soccer league, Major League Soccer, in 2012. The Montreal games of the 2007 FIFA U-20 World Cup and 2014 FIFA U-20 Women's World Cup were held at Olympic Stadium, and the venue hosted Montreal games in the 2015 FIFA Women's World Cup.


title: Montreal

text: Montreal is the site of a high-profile auto racing event each year: the Canadian Grand Prix of Formula One (F1) racing. This race takes place on the Circuit Gilles Villeneuve on Île Notre-Dame. In 2009, the race was dropped from the Formula One calendar, to the chagrin of some fans, but the Canadian Grand Prix returned to the Formula One calendar in 2010. It was dropped from the calendar again since 2020, due to COVID-19 pandemic. The Circuit Gilles Villeneuve also hosted a round of the Champ Car World Series from 2002 to 2007, and was home to the NAPA Auto Parts 200, a NASCAR Nationwide Series race, and the Montréal 200, a Grand Am Rolex Sports Car Series race.


title: Montreal

text: Uniprix Stadium, built in 1993 on the site of Jarry Park, is used for the Rogers Cup men's and women's tennis tournaments. The men's tournament is a Masters 1000 event on the ATP Tour, and the women's tournament is a Premier tournament on the WTA Tour. The men's and women's tournaments alternate between Montreal and Toronto every year.


title: Montreal

text: Montreal was the host of the 1976 Summer Olympic Games. The stadium cost $1.5 billion; with interest that figure ballooned to nearly $3 billion, and was paid off in December 2006. Montreal also hosted the first ever World Outgames in the summer of 2006, attracting over 16,000 participants engaged in 35 sporting activities.


title: Montreal

text: Montreal was the host city for the 17th unicycling world championship and convention (UNICON) in August 2014.


title: Montreal

text: Montreal is Canada's second-largest media market, and the centre of francophone Canada's media industry.


title: Montreal

text: There are four over-the-air English-language television stations: CBMT-DT (CBC Television), CFCF-DT (CTV), CKMI-DT (Global) and CJNT-DT (Citytv). There are also five over-the-air French-language television stations: CBFT-DT (Ici Radio-Canada), CFTM-DT (TVA), CFJP-DT (Noovo), CIVM-DT (Télé-Québec), and CFTU-DT (Canal Savoir).


title: Montreal

text: Montreal has three daily newspapers, the English-language "Montreal Gazette" and the French-language "Le Journal de Montréal", and "Le Devoir"; another French-language daily, "La Presse", became an online daily in 2018. There are two free French dailies, "Métro" and "24 Heures". Montreal has numerous weekly tabloids and community newspapers serving various neighbourhoods, ethnic groups and schools.


title: Montreal

text: The head of the city government in Montreal is the mayor, who is first among equals in the city council.


title: Montreal

text: The city council is a democratically elected institution and is the final decision-making authority in the city, although much power is centralized in the executive committee. The council consists of 65 members from all boroughs. The council has jurisdiction over many matters, including public security, agreements with other governments, subsidy programs, the environment, urban planning, and a three-year capital expenditure program. The council is required to supervise, standardize or approve certain decisions made by the borough councils.


title: Montreal

text: Reporting directly to the council, the executive committee exercises decision-making powers similar to those of the cabinet in a parliamentary system and is responsible for preparing various documents including budgets and by-laws, submitted to the council for approval. The decision-making powers of the executive committee cover, in particular, the awarding of contracts or grants, the management of human and financial resources, supplies and buildings. It may also be assigned further powers by the city council.


title: Montreal

text: Standing committees are the prime instruments for public consultation. They are responsible for the public study of pending matters and for making the appropriate recommendations to the council. They also review the annual budget forecasts for departments under their jurisdiction. A public notice of meeting is published in both French and English daily newspapers at least seven days before each meeting. All meetings include a public question period. The standing committees, of which there are seven, have terms lasting two years. In addition, the City Council may decide to create special committees at any time. Each standing committee is made up of seven to nine members, including a chairman and a vice-chairman. The members are all elected municipal officers, with the exception of a representative of the government of Quebec on the public security committee.


title: Montreal

text: The city is only one component of the larger Montreal Metropolitan Community (Communauté Métropolitaine de Montréal, CMM), which is in charge of planning, coordinating, and financing economic development, public transportation, garbage collection and waste management, etc., across the metropolitan area. The president of the CMM is the mayor of Montreal. The CMM covers , with 3.6 million inhabitants in 2006.


title: Montreal

text: Montreal is the seat of the judicial district of Montreal, which includes the city and the other communities on the island.


title: Montreal

text: Law enforcement on the island itself is provided by the "Service de Police de la Ville de Montréal," or the SPVM for short.


title: Montreal

text: The overall crime rate in Montreal has declined, with a few notable exceptions, with murders at the lowest rate since 1972 (23 murders in 2016). Sex crimes have increased 14.5 per cent between 2015 and 2016 and fraud cases have increased by 13 per cent over the same period. The major criminal organizations active in Montreal are the Rizzuto crime family, Hells Angels and West End Gang.


title: Montreal

text: The education system in Quebec is different from other systems in North America. Between high school (which ends at grade 11) and university students must go through an additional school called CEGEP. CEGEPs offer pre-university (2-years) and technical (3-years) programs. In Montreal, seventeen CEGEPs offer courses in French and five in English.


title: Montreal

text: French-language elementary and secondary public schools in Montreal are operated by the Centre de services scolaire de Montréal (CSDM), Centre de services scolaire Marguerite-Bourgeoys and the Centre de services scolaire de la Pointe-de-l'Île.


title: Montreal

text: English-language elementary and secondary public schools on Montreal Island are operated by the English Montreal School Board and the Lester B. Pearson School Board.


title: Montreal

text: With four universities, seven other degree-awarding institutions, and 12 CEGEPs in an radius, Montreal has the highest concentration of post-secondary students of all major cities in North America (4.38 students per 100 residents, followed by Boston at 4.37 students per 100 residents).


title: Montreal

text: Additionally, two French-language universities, Université de Sherbrooke and Université Laval have campuses in the nearby suburb of Longueuil on Montreal's south shore. Also, l"'Institut de pastorale des Dominicains" is Montreal's university centre of Ottawa's Collège Universitaire Dominicain/Dominican University College. The "Faculté de théologie évangélique" is Nova Scotia's Acadia University Montreal based serving French Protestant community in Canada by offering both a Bachelor and a Master program in theology


title: Montreal

text: Like many major cities, Montreal has a problem with vehicular traffic congestion. Commuting traffic from the cities and towns in the West Island (such as Dollard-des-Ormeaux and Pointe-Claire) is compounded by commuters entering the city that use twenty-four road crossings from numerous off-island suburbs on the North and South Shores. The width of the Saint Lawrence River has made the construction of fixed links to the south shore expensive and difficult. There are presently four road bridges (including two of the country's busiest) along with one bridge-tunnel, two railway bridges, and a Metro line. The far narrower Rivière des Prairies to the city's north, separating Montreal from Laval, is spanned by nine road bridges (seven to the city of Laval and two that span directly to the north shore) and a Metro line.


title: Montreal

text: The island of Montreal is a hub for the Quebec Autoroute system, and is served by Quebec Autoroutes A-10 (known as the Bonaventure Expressway on the island of Montreal), A-15 (aka the Decarie Expressway south of the A-40 and the Laurentian Autoroute to the north of it), A-13 (aka Chomedey Autoroute), A-20, A-25, A-40 (part of the Trans-Canada Highway system, and known as "The Metropolitan" or simply "The Met" in its elevated mid-town section), A-520 and R-136 (aka the Ville-Marie Autoroute). Many of these Autoroutes are frequently congested at rush hour. However, in recent years, the government has acknowledged this problem and is working on long-term solutions to alleviate the congestion. One such example is the extension of Quebec Autoroute 30 on Montreal's south shore, which will be a bypass for trucks and intercity traffic.


title: Montreal

text: Public local transport is served by a network of buses, subways, and commuter trains that extend across and off the island. The subway and bus system are operated by the Société de transport de Montréal (STM, Montreal Transit Society). The STM bus network consists of 203 daytime and 23 night time routes. STM bus routes serve 1,347,900 passengers on an average weekday in 2010. It also provides adapted transport and wheelchair-accessible buses. The STM won the award of Outstanding Public Transit System in North America by the APTA in 2010. It was the first time a Canadian company won this prize.


title: Montreal

text: The Metro was inaugurated in 1966 and has 68 stations on four lines. It is Canada's busiest subway system in total daily passenger usage, serving 1,050,800 passengers on an average weekday (as of Q1 2010). Each station was designed by different architects with individual themes and features original artwork, and the trains run on rubber tires, making the system quieter than most. The project was initiated by Montreal Mayor Jean Drapeau, who later brought the Summer Olympic Games to Montreal in 1976. The Metro system has long had a station on the South Shore in Longueuil, and in 2007 was extended to the city of Laval, north of Montreal, with three new stations. The metro has recently been modernizing its trains, purchasing new "Azur" models with inter-connected wagons.


title: Montreal

text: Montreal has two international airports, one for passengers only, the other for cargo. Pierre Elliott Trudeau International Airport (also known as "Dorval Airport") in the City of Dorval serves all commercial passenger traffic and is the headquarters of Air Canada and Air Transat. To the north of the city is Montreal Mirabel International Airport in Mirabel, which was envisioned as Montreal's primary airport but which now serves cargo flights along with MEDEVACs and general aviation and some passenger services. In 2018, Trudeau was the third busiest airport in Canada by passenger traffic and aircraft movements, handling 19.42 million passengers, and 240,159 aircraft movements. With 63% of its passengers being on non-domestic flights it has the largest percentage of international flights of any Canadian airport.


title: Montreal

text: It is one of Air Canada's major hubs and operates on average approximately 2,400 flights per week between Montreal and 155 destinations, spread on five continents.


title: Montreal

text: Airlines servicing Trudeau offer year-round non-stop flights to five continents, namely Africa, Asia, Europe, North America and South America. It is one of only two airports in Canada with direct flights to five continents or more.


title: Montreal

text: Montreal-based Via Rail Canada provides rail service to other cities in Canada, particularly to Quebec City and Toronto along the Quebec City – Windsor Corridor. Amtrak, the U.S. national passenger rail system, operates its "Adirondack" daily to New York. All intercity trains and most commuter trains operate out of Central Station.


title: Montreal

text: Canadian Pacific Railway (CPR), headquartered in Calgary, Alberta, was founded here in 1881. Its corporate headquarters occupied Windsor Station at 910 Peel Street until 1995. With the Port of Montreal kept open year-round by icebreakers, lines to Eastern Canada became surplus, and now Montreal is the railway's eastern and intermodal freight terminus. CPR connects at Montreal with the Port of Montreal, the Delaware and Hudson Railway to New York, the Quebec Gatineau Railway to Quebec City and Buckingham, the Central Maine and Quebec Railway to Halifax, and Canadian National Railway (CN). The CPR's flagship train, "The Canadian", ran daily from Windsor Station to Vancouver, but in 1978 all passenger services were transferred to Via. Since 1990, "The Canadian" has terminated in Toronto instead of in Montreal.


title: Montreal

text: Montreal-based CN was formed in 1919 by the Canadian government following a series of country-wide rail bankruptcies. It was formed from the Grand Trunk, Midland and Canadian Northern Railways, and has risen to become CPR's chief rival in freight carriage in Canada. Like the CPR, CN divested itself of passenger services in favour of Via. CN's flagship train, the "Super Continental", ran daily from Central Station to Vancouver and subsequently became a Via train in 1978. It was eliminated in 1990 in favour of rerouting "The Canadian".


title: Montreal

text: The commuter rail system is managed and operated by Exo, and reaches the outlying areas of Greater Montreal with six lines. It carried an average of 79,000 daily passengers in 2014, making it the seventh busiest in North America following New York, Chicago, Toronto, Boston, Philadelphia, and Mexico City.


title: Montreal

text: On April 22, 2016, the forthcoming automated rapid transit system, the Réseau express métropolitain (REM), was unveiled. Groundbreaking occurred April 12, 2018, and construction of the networkconsisting of three branches, 26 stations, and the conversion of the region's busiest commuter railwaycommenced the following month. To be opened in three phases as of 2022, the REM will be completed by mid-2024, becoming the fourth largest automated rapid transit network after the Dubai Metro, the Singapore Mass Rapid Transit, and the Vancouver SkyTrain. Most of it will be financed by pension fund manager Caisse de dépôt et placement du Québec (CDPQ Infra).


title: Montreal

text: On December 15, 2020, CDPQ Infra announced another network, the REM de l'Est. None of its trackage will link to the initial network, although its inner terminus close to the city's centre is to double as a passenger interchange. Covering the eastern half of the island, it is to be in length with 23 stations. Plans to elevate its trunk segment through the eastern end of the city centre and an adjacent inner-city district, however, have become controversial, while the north-bound one of its pair of branches is to be tunnelled through suburban districts. And by January 18, 2021, North Shore mayors of municipalities north of the Rivière des Mille Îles announced their desires to erect yet another REM network paralleling the river to link their North Shore communities between Oka and L'Assomption, a distance of roughly .


title: Montreal

text: The city of Montreal is world-renowned for being in the top 20 most cyclist-friendly cities around the globe. It follows that they have one of the world's most successful bike share systems in BIXI. First launched in 2009 with Montreal-based PBSC Urban Solutions ICONIC bikes, the bicycle-sharing scheme has since grown its fleet to include 750 docking and charging stations across the different neighbourhoods with 9000 bikes available for users. In what the STM states is a mission to combine different forms of mobility, transit card holders can now take advantage of their membership to also rent bicycles at select stations.


title: Bill Paxton

text: William Paxton (May 17, 1955 – February 25, 2017) was an American actor and filmmaker. He appeared in films such as "Weird Science" (1985), "Aliens" (1986), "Near Dark" (1987), "Tombstone" (1993), "True Lies" (1994), "Apollo 13" (1995), "Twister" (1996), "Titanic" (1997), "A Simple Plan" (1998), "Edge of Tomorrow" (2014), and "Nightcrawler" (2014).


title: Bill Paxton

text: Paxton starred in the HBO drama series "Big Love" (2006–2011), for which he earned three Golden Globe Award nominations during the show's run. He was nominated for a Primetime Emmy Award and a Screen Actors Guild Award for portraying Randall McCoy in the History channel miniseries "Hatfields & McCoys" (2012).


title: Bill Paxton

text: Bill Paxton was born in Fort Worth, Texas, on May 17, 1955, the son of Mary Lou ("née" Gray; 1926–2016) and John Lane Paxton (1920–2011). His mother was a Roman Catholic who raised him and his siblings in her faith. His father was a businessman, lumber wholesaler, museum executive, and (during his son's career) an occasional actor, notably appearing in Sam Raimi's "Spider-Man" films as Bernard Houseman and alongside Paxton in "A Simple Plan" (1998). Paxton was of Austrian, Dutch, English, French, German, Norwegian, Scotch-Irish, Scottish, Swiss, and Welsh descent. His great-great-grandfather was Elisha Franklin Paxton (1828–1863), a brigadier general in the Confederate Army during the Civil War who was killed commanding the Stonewall Brigade at the Battle of Chancellorsville.


title: Bill Paxton

text: Paxton is distantly related to actress Sara Paxton and was the great-nephew of Mary Paxton Keeley, a prominent journalist and close friend of Bess Truman. At the age of eight, he was in the crowd when President John F. Kennedy emerged from the Hotel Texas in Fort Worth on the morning of his assassination on November 22, 1963. Photographs of Paxton being lifted above the crowd are on display at the Sixth Floor Museum at Dealey Plaza in Dallas, Texas. He later co-produced the film "Parkland" about the assassination. He graduated from Arlington Heights High School in Fort Worth in 1973, after which he studied at Richmond College in London, alongside his old high school friend Danny Martin. There, they met fellow Texas native Tom Huckabee, with whom they made Super 8 short films for which they built their own sets. One of Paxton's first lead roles was in Huckabee's experimental film "Taking Tiger Mountain". Paxton subsequently moved to Los Angeles, where he worked in props and art departments and as a parking valet at the Beverly Hills Hotel. After being rejected by film schools in Southern California, he switched his ambitions from directing to acting.


title: Bill Paxton

text: Among Paxton's earliest roles were as a mortuary assistant in "Mortuary" (1983), a minor role as a punk in "The Terminator" (1984), a minor role as a bartender in "Streets of Fire", a supporting role as the lead protagonist's bullying older brother Chet Donnelly in John Hughes's "Weird Science" (1985), and Private William Hudson in "Aliens" (1986).


title: Bill Paxton

text: He directed several short films, including the music video for Barnes & Barnes's novelty song "Fish Heads", which aired during "Saturday Night Live"s low-rated 1980–81 season and was in heavy rotation during the early days of Canadian music channel MuchMusic. He was cast in a music video for the 1982 Pat Benatar song "Shadows of the Night" in which he appeared as a Nazi radio officer.


title: Bill Paxton

text: In 1981, Paxton worked in the movie "Stripes" as a soldier, in the bar scene with John Candy and Bill Murray.


title: Bill Paxton

text: He worked alongside Arnold Schwarzenegger in James Cameron's "The Terminator" (1984) and in "Commando" (1985). He reunited with Cameron on "Aliens" (1986). His performance in the latter film as Private Hudson earned him the Saturn Award for Best Supporting Actor.


title: Bill Paxton

text: He also appeared in "Weird Science" (1985). In 1987, Paxton played the most psychotic of the vampires, Severen, in Kathryn Bigelow's critically acclaimed neo-Western horror film, "Near Dark".


title: Bill Paxton

text: In 1990, Paxton appeared in "Predator 2" (1990). He collaborated with James Cameron again on "True Lies" (1994) and "Titanic" (1997), the latter of which was the highest-grossing film of all time at its release. In his other roles, Paxton played Morgan Earp in "Tombstone" (1993), Fred Haise in "Apollo 13" (1995), Bill Harding in "Twister" (1996), and lead roles in dark dramas such as "One False Move" (1992) and "A Simple Plan" (1998). In 1990, he co-starred with Charlie Sheen and Michael Biehn in "Navy Seals".


title: Bill Paxton

text: Paxton also appeared in "Indian Summer" (1993) and "Mighty Joe Young" (1998). After 2000, he appeared in "U-571" (2000), "Vertical Limit" (2000), "Frailty" (2001), "Broken Lizard's Club Dread" (2004), "Thunderbirds" (2004), "Edge of Tomorrow" (2014) and "Nightcrawler" (2014).


title: Bill Paxton

text: Paxton directed the feature films "Frailty" (2001), in which he also starred, and "The Greatest Game Ever Played" (2005). Four years after appearing in "Titanic", he joined Cameron on an expedition to the wreck of the Titanic. A film about this trip, "Ghosts of the Abyss" was released in 2003. He also appeared in the music video for Limp Bizkit's 2003 song "Eat You Alive" as a sheriff. In addition, Paxton also played a character in both "" and "".


title: Bill Paxton

text: His highest-profile television performances received much positive attention, including his lead role in HBO's "Big Love" (2006–2011), for which Paxton received three Golden Globe Award nominations. He also received positive reviews for his performance in the History Channel's miniseries "Hatfields & McCoys" (2012), for which he was nominated for an Emmy Award alongside co-star, Kevin Costner.


title: Bill Paxton

text: In 2014, he played the role of the villainous John Garrett in "Agents of S.H.I.E.L.D.", and a supporting role in "Edge of Tomorrow" (2014). He starred alongside Jon Bernthal, Rose McGowan and John Malkovich as a playable character in the 2014 video game "" (downloadable "Exo Zombies" mode). Paxton starred as General Sam Houston in the Western miniseries "Texas Rising" for The History Channel in 2015.


title: Bill Paxton

text: In February 2016, Paxton was cast as Detective Frank Rourke for "Training Day", a crime-thriller television series set 15 years after the events of the eponymous 2001 movie. It premiered a year later. His final film appearance was in "The Circle" (2017), released two months after his death.


title: Bill Paxton

text: In 1982, Paxton and his friend Andrew Todd Rosenthal formed a new wave musical band called Martini Ranch. The band released its only full-length album, "Holy Cow", in 1988 on Sire Records. The album was produced by Devo member Bob Casale, and featured guest appearances by two other members of that band. The music video for the band's single "Reach" was directed by James Cameron. In 2018, his performances as Peter "Coconut Pete" Wabash in "Broken Lizard's Club Dread" were released posthumously on the album "Take Another Hit: The Best of Coconut Pete".


title: Bill Paxton

text: Paxton married Kelly Rowan in 1979 and they divorced a year later. He later met Louise Newbury on the Number 13 bus in London, where she was a student, and they were married in 1987. They lived in Ojai, California, and had two children: son James (born 1994), who is also an actor, and daughter Lydia (born 1997).


title: Bill Paxton

text: In early 2017, Paxton stated in an interview on "WTF with Marc Maron" that he had a damaged aortic heart valve, resulting from rheumatic fever which he contracted at the age of 14. On February 14, he underwent open-heart surgery at Cedars-Sinai Medical Center in Los Angeles to repair the damaged valve and correct an aortic aneurysm. A day later, he underwent an emergency second surgery to repair a damaged coronary artery. His condition deteriorated over the following 10 days, until he had a fatal stroke on February 25 and died at the age of 61. He was cremated and his ashes were buried at the Forest Lawn Memorial Park of Hollywood Hills.


title: Bill Paxton

text: One year after Paxton's death, his family filed a wrongful death lawsuit against Ali Khoynezhad, the surgeon who performed his operation, alleging that Khoynezhad used "high-risk and unconventional" methods and that he was not present in the operating room when Paxton developed complications such as ventricular dysfunction, tachycardia, and a compromised right coronary artery, which they claim contributed to the coronary artery damage that necessitated a second surgery and ultimately led to Paxton's death.


title: Bill Paxton

text: In February 2022, Paxton's family reached a partial settlement with General Anesthesia Specialists Partnership for $1 million. In August 2022, the case was settled against Cedars-Sinai and Dr. Khoynezhad under undisclosed terms.


title: Bill Paxton

text: Many dozens of filmmakers and actors across the entertainment spectrum paid tribute to Paxton in the aftermath of his death.


title: Bill Paxton

text: On February 26, 2017, while introducing the annual "In Memoriam" segment at the 89th Academy Awards the day after Paxton's death, a visibly emotional Jennifer Aniston paid tribute to him. His "Big Love" co-star Chloë Sevigny remembered him as "one of the less cynical, jaded people [she'd] ever met in the business" and said, "He believed in entertainment being transportive and transformative. He believed in the magic of what we can bring to people. That was really a gift that he gave to me." The television show "Marvel's Agents of S.H.I.E.L.D." paid tribute at the end of its season 4 episode "What If...", and a number of storm chasers paid tribute to his role in "Twister" by spelling out his initials "BP" via the Spotter Network.


title: Bill Paxton

text: The 2017 film "Call Me by Your Name" was dedicated to Paxton's memory. The film's producer Peter Spears explained that his husband Brian Swardstrom, who was also Paxton's best friend and agent, once visited the set with Paxton during filming and befriended the film's director Luca Guadagnino, who ultimately decided to dedicate the film "in loving memory of Bill Paxton". Close friend and frequent collaborator James Cameron wrote a tribute in an article for "Vanity Fair", detailing their 36-year friendship and expressing regret over the projects they would not be able to make together. The 2019 John Travolta film "The Fanatic", which co-starred Paxton's son James, was dedicated to Paxton. James would later play a younger version of Paxton's S.H.I.E.L.D. character in the final season which served as a tribute to his role in the show. Cameron's 2022 film, "" was dedicated to Paxton's memory as well as James Horner who previously worked with Cameron on "Aliens", "Titanic" and "the first Avatar". Paxton worked with both Cameron and Horner on the former two films. Cameron had hoped to cast Paxton in the Avatar sequels before his death.


title: Mars

text: Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin atmosphere (less than 1% that of Earth's), and has a crust primarily composed of elements similar to Earth's crust, as well as a core made of iron and nickel. Mars has surface features such as impact craters, valleys, dunes and polar ice caps. It has two small and irregularly shaped moons, Phobos and Deimos.


title: Mars

text: Some of the most notable surface features on Mars include Olympus Mons, the largest volcano and highest known mountain in the Solar System and Valles Marineris, one of the largest canyons in the Solar System. The Borealis basin in the Northern Hemisphere covers approximately 40% of the planet and may be a large impact feature. Days and seasons on Mars are comparable to those of Earth, as the planets have a similar rotation period and tilt of the rotational axis relative to the ecliptic plane. Liquid water on the surface of Mars cannot exist due to low atmospheric pressure, which is less than 1% of the atmospheric pressure on Earth. Both of Mars's polar ice caps appear to be made largely of water. In the distant past, Mars was likely wetter, and thus possibly more suited for life. It is not known whether life has ever existed on Mars.


title: Mars

text: Mars has been explored by several uncrewed spacecraft, beginning with "Mariner 4" in 1965. NASA's "Viking 1" lander transmitted in 1976 the first images from the Martian surface. Two countries have successfully deployed rovers on Mars, the United States first doing so with "Sojourner" in 1997 and China with "Zhurong" in 2021. There are also planned future missions to Mars, such as a Mars sample-return mission set to happen in 2026, and the "Rosalind Franklin" rover mission, which was intended to launch in 2018 but was delayed to 2024 at the earliest, with a more likely launch date at 2028.


title: Mars

text: Mars can be viewed from Earth with the naked eye, as can its reddish coloring. This appearance, due to the iron oxide prevalent on its surface, has led to Mars often being called the Red Planet. It is among the brightest objects in Earth's sky, with an apparent magnitude that reaches −2.94, comparable to that of Jupiter and surpassed only by Venus, the Moon and the Sun. Historically, Mars has been observed since ancient times, and over the millennia has been featured in culture and the arts in ways that have reflected humanity's growing knowledge of it.


title: Mars

text: The history of observations of Mars is marked by the oppositions of Mars when the planet is closest to Earth and hence is most easily visible, which occur every couple of years. Even more notable are the perihelic oppositions of Mars, which are distinguished because Mars is close to perihelion, making it even closer to Earth.


title: Mars

text: The ancient Sumerians named Mars Nergal, the god of war and plague. During Sumerian times, Nergal was a minor deity of little significance, but, during later times, his main cult center was the city of Nineveh. In Mesopotamian texts, Mars is referred to as the "star of judgement of the fate of the dead." The existence of Mars as a wandering object in the night sky was also recorded by the ancient Egyptian astronomers and, by 1534 BCE, they were familiar with the retrograde motion of the planet. By the period of the Neo-Babylonian Empire, the Babylonian astronomers were making regular records of the positions of the planets and systematic observations of their behavior. For Mars, they knew that the planet made 37 synodic periods, or 42 circuits of the zodiac, every 79 years. They invented arithmetic methods for making minor corrections to the predicted positions of the planets. In Ancient Greece, the planet was known as . Commonly, the Greek name for the planet now referred to as Mars, was Ares. It was the Romans who named the planet Mars, for their god of war, often represented by the sword and shield of the planet's namesake.


title: Mars

text: In the fourth century BCE, Aristotle noted that Mars disappeared behind the Moon during an occultation, indicating that the planet was farther away. Ptolemy, a Greek living in Alexandria, attempted to address the problem of the orbital motion of Mars. Ptolemy's model and his collective work on astronomy was presented in the multi-volume collection later called the "Almagest" (from the Arabic for "greatest"), which became the authoritative treatise on Western astronomy for the next fourteen centuries. Literature from ancient China confirms that Mars was known by Chinese astronomers by no later than the fourth century BCE. In the East Asian cultures, Mars is traditionally referred to as the "fire star" (Chinese: ), based on the "Wuxing" system.


title: Mars

text: During the seventeenth century A.D., Tycho Brahe measured the diurnal parallax of Mars that Johannes Kepler used to make a preliminary calculation of the relative distance to the planet. From Brahe's observations of Mars, Kepler deduced that the planet orbited the Sun not in a circle, but in an ellipse. Moreover, Kepler showed that Mars sped up as it approached the Sun and slowed down as it moved farther away, in a manner that later physicists would explain as a consequence of the conservation of angular momentum. When the telescope became available, the diurnal parallax of Mars was again measured in an effort to determine the Sun-Earth distance. This was first performed by Giovanni Domenico Cassini in 1672. The early parallax measurements were hampered by the quality of the instruments. The only occultation of Mars by Venus observed was that of 13 October 1590, seen by Michael Maestlin at Heidelberg. In 1610, Mars was viewed by Italian astronomer Galileo Galilei, who was first to see it via telescope. The first person to draw a map of Mars that displayed any terrain features was the Dutch astronomer Christiaan Huygens.


title: Mars

text: By the 19th century, the resolution of telescopes reached a level sufficient for surface features to be identified. On 5 September 1877, a perihelic opposition of Mars occurred. The Italian astronomer Giovanni Schiaparelli used a telescope in Milan to help produce the first detailed map of Mars. These maps notably contained features he called "canali", which were later shown to be an optical illusion. These "canali" were supposedly long, straight lines on the surface of Mars, to which he gave names of famous rivers on Earth. His term, which means "channels" or "grooves", was popularly mistranslated in English as "canals".


title: Mars

text: Influenced by the observations, the orientalist Percival Lowell founded an observatory which had 30- and 45-centimetre (12- and 18-in) telescopes. The observatory was used for the exploration of Mars during the last good opportunity in 1894 and the following less favorable oppositions. He published several books on Mars and life on the planet, which had a great influence on the public. The "canali" were independently observed by other astronomers, like Henri Joseph Perrotin and Louis Thollon in Nice, using one of the largest telescopes of that time.


title: Mars

text: The seasonal changes (consisting of the diminishing of the polar caps and the dark areas formed during Martian summer) in combination with the canals led to speculation about life on Mars, and it was a long-held belief that Mars contained vast seas and vegetation. As bigger telescopes were used, fewer long, straight "canali" were observed. During observations in 1909 by Antoniadi with an telescope, irregular patterns were observed, but no "canali" were seen.


title: Mars

text: Mars is approximately half the diameter of Earth, with a surface area only slightly less than the total area of Earth's dry land. Mars is less dense than Earth, having about 15% of Earth's volume and 11% of Earth's mass, resulting in about 38% of Earth's surface gravity. The red-orange appearance of the Martian surface is caused by iron(III) oxide, or rust. It can look like butterscotch; other common surface colors include golden, brown, tan, and greenish, depending on the minerals present.


title: Mars

text: Like Earth, Mars has differentiated into a dense metallic core overlaid by less dense materials. Current models of its interior imply a core consisting primarily of iron and nickel with about 16–17% sulfur. This iron(II) sulfide core is thought to be twice as rich in lighter elements as Earth's. The core is surrounded by a silicate mantle that formed many of the tectonic and volcanic features on the planet, but it appears to be dormant. Besides silicon and oxygen, the most abundant elements in the Martian crust are iron, magnesium, aluminium, calcium, and potassium. The average thickness of the planet's crust is about , with a maximum thickness of . By comparison, Earth's crust averages in thickness.


title: Mars

text: Mars is seismically active. InSight has detected and recorded over 450 marsquakes and related events in 2019. In 2021 it was reported that based on eleven low-frequency Marsquakes detected by the "InSight" lander the core of Mars is indeed liquid and has a radius of about and a temperature around 1900–2000 K. The Martian core radius is more than half the radius of Mars and about half the size of the Earth's core. This is somewhat larger than models predicted, suggesting that the core contains some amount of lighter elements like oxygen and hydrogen in addition to the iron–nickel alloy and about 15% of sulfur.


title: Mars

text: The core of Mars is overlaid by the rocky mantle, which, however, does not seem to have a layer analogous to the Earth's lower mantle. The Martian mantle appears to be solid down to the depth of about 500 km, where the low-velocity zone (partially melted asthenosphere) begins. Below the asthenosphere the velocity of seismic waves starts to grow again and at the depth of about 1050 km there lies the boundary of the transition zone. At the surface of Mars there lies a crust with the average thickness of about 24–72 km.


title: Mars

text: Mars is a terrestrial planet with a surface that consists of minerals containing silicon and oxygen, metals, and other elements that typically make up rock. The Martian surface is primarily composed of tholeiitic basalt, although parts are more silica-rich than typical basalt and may be similar to andesitic rocks on Earth, or silica glass. Regions of low albedo suggest concentrations of plagioclase feldspar, with northern low albedo regions displaying higher than normal concentrations of sheet silicates and high-silicon glass. Parts of the southern highlands include detectable amounts of high-calcium pyroxenes. Localized concentrations of hematite and olivine have been found. Much of the surface is deeply covered by finely grained iron(III) oxide dust.


title: Mars

text: Although Mars has no evidence of a structured global magnetic field, observations show that parts of the planet's crust have been magnetized, suggesting that alternating polarity reversals of its dipole field have occurred in the past. This paleomagnetism of magnetically susceptible minerals is similar to the alternating bands found on Earth's ocean floors. One theory, published in 1999 and re-examined in October 2005 (with the help of the "Mars Global Surveyor"), is that these bands suggest plate tectonic activity on Mars four billion years ago, before the planetary dynamo ceased to function and the planet's magnetic field faded.


title: Mars

text: Scientists have theorized that during the Solar System's formation Mars was created as the result of a random process of run-away accretion of material from the protoplanetary disk that orbited the Sun. Mars has many distinctive chemical features caused by its position in the Solar System. Elements with comparatively low boiling points, such as chlorine, phosphorus, and sulfur, are much more common on Mars than Earth; these elements were probably pushed outward by the young Sun's energetic solar wind.


title: Mars

text: After the formation of the planets, all were subjected to the so-called "Late Heavy Bombardment". About 60% of the surface of Mars shows a record of impacts from that era, whereas much of the remaining surface is probably underlain by immense impact basins caused by those events. There is evidence of an enormous impact basin in the Northern Hemisphere of Mars, spanning , or roughly four times the size of the Moon's South Pole – Aitken basin, the largest impact basin yet discovered. This theory suggests that Mars was struck by a Pluto-sized body about four billion years ago. The event, thought to be the cause of the Martian hemispheric dichotomy, created the smooth Borealis basin that covers 40% of the planet.


title: Mars

text: The geological history of Mars can be split into many periods, but the following are the three primary periods:


title: Mars

text: Geological activity is still taking place on Mars. The Athabasca Valles is home to sheet-like lava flows created about 200 mya. Water flows in the grabens called the Cerberus Fossae occurred less than 20 Mya, indicating equally recent volcanic intrusions. The "Mars Reconnaissance Orbiter" has captured images of avalanches.


title: Mars

text: The "Phoenix" lander returned data showing Martian soil to be slightly alkaline and containing elements such as magnesium, sodium, potassium and chlorine. These nutrients are found in soils on Earth. They are necessary for growth of plants. Experiments performed by the lander showed that the Martian soil has a basic pH of 7.7, and contains 0.6% of the salt perchlorate, concentrations that are toxic to humans.


title: Mars

text: Streaks are common across Mars and new ones appear frequently on steep slopes of craters, troughs, and valleys. The streaks are dark at first and get lighter with age. The streaks can start in a tiny area, then spread out for hundreds of metres. They have been seen to follow the edges of boulders and other obstacles in their path. The commonly accepted theories include that they are dark underlying layers of soil revealed after avalanches of bright dust or dust devils. Several other explanations have been put forward, including those that involve water or even the growth of organisms.


title: Mars

text: Water in its liquid form cannot exist on the surface of Mars due to low atmospheric pressure, which is less than 1% that of Earth's, except at the lowest elevations for short periods. The two polar ice caps appear to be made largely of water. The volume of water ice in the south polar ice cap, if melted, would be enough to cover the entire surface of the planet with a depth of . Large quantities of ice are thought to be trapped within the thick cryosphere of Mars. Radar data from "Mars Express" and the "Mars Reconnaissance Orbiter" (MRO) show large quantities of ice at both poles, and at middle latitudes. The Phoenix lander directly sampled water ice in shallow Martian soil on 31 July 2008.


title: Mars

text: Landforms visible on Mars strongly suggest that liquid water has existed on the planet's surface. Huge linear swathes of scoured ground, known as outflow channels, cut across the surface in about 25 places. These are thought to be a record of erosion caused by the catastrophic release of water from subsurface aquifers, though some of these structures have been hypothesized to result from the action of glaciers or lava. One of the larger examples, Ma'adim Vallis, is long, much greater than the Grand Canyon, with a width of and a depth of in places. It is thought to have been carved by flowing water early in Mars's history. The youngest of these channels are thought to have formed only a few million years ago. Elsewhere, particularly on the oldest areas of the Martian surface, finer-scale, dendritic networks of valleys are spread across significant proportions of the landscape. Features of these valleys and their distribution strongly imply that they were carved by runoff resulting from precipitation in early Mars history. Subsurface water flow and groundwater sapping may play important subsidiary roles in some networks, but precipitation was probably the root cause of the incision in almost all cases.


title: Mars

text: Along crater and canyon walls, there are thousands of features that appear similar to terrestrial gullies. The gullies tend to be in the highlands of the Southern Hemisphere and to face the Equator; all are poleward of 30° latitude. A number of authors have suggested that their formation process involves liquid water, probably from melting ice, although others have argued for formation mechanisms involving carbon dioxide frost or the movement of dry dust. No partially degraded gullies have formed by weathering and no superimposed impact craters have been observed, indicating that these are young features, possibly still active. Other geological features, such as deltas and alluvial fans preserved in craters, are further evidence for warmer, wetter conditions at an interval or intervals in earlier Mars history. Such conditions necessarily require the widespread presence of crater lakes across a large proportion of the surface, for which there is independent mineralogical, sedimentological and geomorphological evidence. Further evidence that liquid water once existed on the surface of Mars comes from the detection of specific minerals such as hematite and goethite, both of which sometimes form in the presence of water.


title: Mars

text: In 2004, "Opportunity" detected the mineral jarosite. This forms only in the presence of acidic water, showing that water once existed on Mars. The "Spirit" rover found concentrated deposits of silica in 2007 that indicated wet conditions in the past, and in December 2011, the mineral gypsum, which also forms in the presence of water, was found on the surface by NASA's Mars rover Opportunity. It is estimated that the amount of water in the upper mantle of Mars, represented by hydroxyl ions contained within Martian minerals, is equal to or greater than that of Earth at 50–300 parts per million of water, which is enough to cover the entire planet to a depth of .


title: Mars

text: On 18 March 2013, NASA reported evidence from instruments on the "Curiosity" rover of mineral hydration, likely hydrated calcium sulfate, in several rock samples including the broken fragments of "Tintina" rock and "Sutton Inlier" rock as well as in veins and nodules in other rocks like "Knorr" rock and "Wernicke" rock. Analysis using the rover's DAN instrument provided evidence of subsurface water, amounting to as much as 4% water content, down to a depth of , during the rover's traverse from the "Bradbury Landing" site to the "Yellowknife Bay" area in the "Glenelg" terrain. In September 2015, NASA announced that they had found strong evidence of hydrated brine flows in recurring slope lineae, based on spectrometer readings of the darkened areas of slopes. These streaks flow downhill in Martian summer, when the temperature is above −23° Celsius, and freeze at lower temperatures. These observations supported earlier hypotheses, based on timing of formation and their rate of growth, that these dark streaks resulted from water flowing just below the surface. However, later work suggested that the lineae may be dry, granular flows instead, with at most a limited role for water in initiating the process. A definitive conclusion about the presence, extent, and role of liquid water on the Martian surface remains elusive.


title: Mars

text: Researchers suspect much of the low northern plains of the planet were covered with an ocean hundreds of meters deep, though this theory remains controversial. In March 2015, scientists stated that such an ocean might have been the size of Earth's Arctic Ocean. This finding was derived from the ratio of water to deuterium in the modern Martian atmosphere compared to that ratio on Earth. The amount of Martian deuterium is eight times the amount that exists on Earth, suggesting that ancient Mars had significantly higher levels of water. Results from the "Curiosity" rover had previously found a high ratio of deuterium in Gale Crater, though not significantly high enough to suggest the former presence of an ocean. Other scientists caution that these results have not been confirmed, and point out that Martian climate models have not yet shown that the planet was warm enough in the past to support bodies of liquid water. Near the northern polar cap is the wide Korolev Crater, which the Mars Express orbiter found to be filled with approximately of water ice.


title: Mars

text: In November 2016, NASA reported finding a large amount of underground ice in the Utopia Planitia region. The volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior. During observations from 2018 through 2021, the ExoMars Trace Gas Orbiter spotted indications of water, probably subsurface ice, in the Valles Marineris canyon system.


title: Mars

text: Mars has two permanent polar ice caps. During a pole's winter, it lies in continuous darkness, chilling the surface and causing the deposition of 25–30% of the atmosphere into slabs of CO ice (dry ice). When the poles are again exposed to sunlight, the frozen CO sublimes. These seasonal actions transport large amounts of dust and water vapor, giving rise to Earth-like frost and large cirrus clouds. Clouds of water-ice were photographed by the "Opportunity" rover in 2004.


title: Mars

text: The caps at both poles consist primarily (70%) of water ice. Frozen carbon dioxide accumulates as a comparatively thin layer about one metre thick on the north cap in the northern winter only, whereas the south cap has a permanent dry ice cover about eight metres thick. This permanent dry ice cover at the south pole is peppered by flat floored, shallow, roughly circular pits, which repeat imaging shows are expanding by ?? meters per year; this suggests that the permanent CO cover over the south pole water ice is degrading over time. The northern polar cap has a diameter of about , and contains about of ice, which, if spread evenly on the cap, would be thick. (This compares to a volume of for the Greenland ice sheet.) The southern polar cap has a diameter of and a thickness of . The total volume of ice in the south polar cap plus the adjacent layered deposits has been estimated at 1.6 million cubic km. Both polar caps show spiral troughs, which recent analysis of SHARAD ice penetrating radar has shown are a result of katabatic winds that spiral due to the Coriolis effect.


title: Mars

text: The seasonal frosting of areas near the southern ice cap results in the formation of transparent 1-metre-thick slabs of dry ice above the ground. With the arrival of spring, sunlight warms the subsurface and pressure from subliming CO builds up under a slab, elevating and ultimately rupturing it. This leads to geyser-like eruptions of CO gas mixed with dark basaltic sand or dust. This process is rapid, observed happening in the space of a few days, weeks or months, a rate of change rather unusual in geology – especially for Mars. The gas rushing underneath a slab to the site of a geyser carves a spiderweb-like pattern of radial channels under the ice, the process being the inverted equivalent of an erosion network formed by water draining through a single plughole.


title: Mars

text: Although better remembered for mapping the Moon, Johann Heinrich Mädler and Wilhelm Beer were the first areographers. They began by establishing that most of Mars's surface features were permanent and by more precisely determining the planet's rotation period. In 1840, Mädler combined ten years of observations and drew the first map of Mars.


title: Mars

text: Features on Mars are named from a variety of sources. Albedo features are named for classical mythology. Craters larger than roughly 50 km are named for deceased scientists and writers and others who have contributed to the study of Mars. Smaller craters are named for towns and villages of the world with populations of less than 100,000. Large valleys are named for the word "Mars" or "star" in various languages; small valleys are named for rivers.


title: Mars

text: Large albedo features retain many of the older names but are often updated to reflect new knowledge of the nature of the features. For example, "Nix Olympica" (the snows of Olympus) has become "Olympus Mons" (Mount Olympus). The surface of Mars as seen from Earth is divided into two kinds of areas, with differing albedo. The paler plains covered with dust and sand rich in reddish iron oxides were once thought of as Martian "continents" and given names like Arabia Terra ("land of Arabia") or Amazonis Planitia ("Amazonian plain"). The dark features were thought to be seas, hence their names Mare Erythraeum, Mare Sirenum and Aurorae Sinus. The largest dark feature seen from Earth is Syrtis Major Planum. The permanent northern polar ice cap is named Planum Boreum. The southern cap is called Planum Australe.


title: Mars

text: Mars's equator is defined by its rotation, but the location of its Prime Meridian was specified, as was Earth's (at Greenwich), by choice of an arbitrary point; Mädler and Beer selected a line for their first maps of Mars in 1830. After the spacecraft "Mariner 9" provided extensive imagery of Mars in 1972, a small crater (later called Airy-0), located in the Sinus Meridiani ("Middle Bay" or "Meridian Bay"), was chosen by Merton Davies, Harold Masursky, and Gérard de Vaucouleurs for the definition of 0.0° longitude to coincide with the original selection.


title: Mars

text: Because Mars has no oceans and hence no "sea level", a zero-elevation surface had to be selected as a reference level; this is called the "areoid" of Mars, analogous to the terrestrial geoid. Zero altitude was defined by the height at which there is of atmospheric pressure. This pressure corresponds to the triple point of water, and it is about 0.6% of the sea level surface pressure on Earth (0.006 atm).


title: Mars

text: For mapping purposes, the United States Geological Survey divides the surface of Mars into thirty cartographic quadrangles, each named for a classical albedo feature it contains.


title: Mars

text: The shield volcano Olympus Mons ("Mount Olympus") is an extinct volcano in the vast upland region Tharsis, which contains several other large volcanoes. The edifice is over wide. Because the mountain is so large, with complex structure at its edges, allocating a height to it is difficult. Its local relief, from the foot of the cliffs which form its northwest margin to its peak, is over , a little over twice the height of Mauna Kea as measured from its base on the ocean floor. The total elevation change from the plains of Amazonis Planitia, over to the northwest, to the summit approaches , roughly three times the height of Mount Everest, which in comparison stands at just over . Consequently, Olympus Mons is either the tallest or second-tallest mountain in the Solar System; the only known mountain which might be taller is the Rheasilvia peak on the asteroid Vesta, at .


title: Mars

text: The dichotomy of Martian topography is striking: northern plains flattened by lava flows contrast with the southern highlands, pitted and cratered by ancient impacts. It is possible that, four billion years ago, the Northern Hemisphere of Mars was struck by an object one-tenth to two-thirds the size of Earth's Moon. If this is the case, the Northern Hemisphere of Mars would be the site of an impact crater in size, or roughly the area of Europe, Asia, and Australia combined, surpassing Utopia Planitia and the Moon's South Pole–Aitken basin as the largest impact crater in the Solar System.


title: Mars

text: Mars is scarred by a number of impact craters: a total of 43,000 craters with a diameter of or greater have been found. The largest exposed crater is Hellas, which is wide and deep, and is a light albedo feature clearly visible from Earth. There are other notable impact features, such as Argyre, which is around in diameter, and Isidis, which is around in diameter. Due to the smaller mass and size of Mars, the probability of an object colliding with the planet is about half that of Earth. Mars is located closer to the asteroid belt, so it has an increased chance of being struck by materials from that source. Mars is more likely to be struck by short-period comets, "i.e.", those that lie within the orbit of Jupiter.


title: Mars

text: The large canyon, Valles Marineris (Latin for "Mariner Valleys", also known as Agathodaemon in the old canal maps), has a length of and a depth of up to . The length of Valles Marineris is equivalent to the length of Europe and extends across one-fifth the circumference of Mars. By comparison, the Grand Canyon on Earth is only long and nearly deep. Valles Marineris was formed due to the swelling of the Tharsis area, which caused the crust in the area of Valles Marineris to collapse. In 2012, it was proposed that Valles Marineris is not just a graben, but a plate boundary where of transverse motion has occurred, making Mars a planet with possibly a two-tectonic plate arrangement.


title: Mars

text: Images from the Thermal Emission Imaging System (THEMIS) aboard NASA's Mars Odyssey orbiter have revealed seven possible cave entrances on the flanks of the volcano Arsia Mons. The caves, named after loved ones of their discoverers, are collectively known as the "seven sisters". Cave entrances measure from wide and they are estimated to be at least deep. Because light does not reach the floor of most of the caves, it is possible that they extend much deeper than these lower estimates and widen below the surface. "Dena" is the only exception; its floor is visible and was measured to be deep. The interiors of these caverns may be protected from micrometeoroids, UV radiation, solar flares and high energy particles that bombard the planet's surface.


title: Mars

text: Mars lost its magnetosphere 4 billion years ago, possibly because of numerous asteroid strikes, so the solar wind interacts directly with the Martian ionosphere, lowering the atmospheric density by stripping away atoms from the outer layer. Both "Mars Global Surveyor" and "Mars Express" have detected ionised atmospheric particles trailing off into space behind Mars, and this atmospheric loss is being studied by the MAVEN orbiter. Compared to Earth, the atmosphere of Mars is quite rarefied. Atmospheric pressure on the surface today ranges from a low of on Olympus Mons to over in Hellas Planitia, with a mean pressure at the surface level of . The highest atmospheric density on Mars is equal to that found above Earth's surface. The resulting mean surface pressure is only 0.6% of that of Earth . The scale height of the atmosphere is about , which is higher than Earth's , because the surface gravity of Mars is only about 38% of Earth's.


title: Mars

text: The atmosphere of Mars consists of about 96% carbon dioxide, 1.93% argon and 1.89% nitrogen along with traces of oxygen and water. The atmosphere is quite dusty, containing particulates about 1.5 µm in diameter which give the Martian sky a tawny color when seen from the surface. It may take on a pink hue due to iron oxide particles suspended in it. The concentration of methane in the Martian atmosphere fluctuates from about 0.24 ppb during the northern winter to about 0.65 ppb during the summer. Estimates of its lifetime range from 0.6 to 4 years, so its presence indicates that an active source of the gas must be present. Methane could be produced by non-biological process such as serpentinization involving water, carbon dioxide, and the mineral olivine, which is known to be common on Mars, or by Martian life.


title: Mars

text: Compared to Earth, its higher concentration of atmospheric CO and lower surface pressure may be why sound is attenuated more on Mars, where natural sources are rare apart from the wind. Using acoustic recordings collected by the "Perseverance" rover, researchers concluded that the speed of sound there is approximately 240 m/s for frequencies below 240 Hz, and 250 m/s for those above.


title: Mars

text: Auroras have been detected on Mars. Because Mars lacks a global magnetic field, the types and distribution of auroras there differ from those on Earth; rather than being mostly restricted to polar regions, a Martian aurora can encompass the planet. In September 2017, NASA reported radiation levels on the surface of the planet Mars were temporarily doubled, and were associated with an aurora 25 times brighter than any observed earlier, due to a massive, and unexpected, solar storm in the middle of the month.


title: Mars

text: Of all the planets in the Solar System, the seasons of Mars are the most Earth-like, due to the similar tilts of the two planets' rotational axes. The lengths of the Martian seasons are about twice those of Earth's because Mars's greater distance from the Sun leads to the Martian year being about two Earth years long. Martian surface temperatures vary from lows of about to highs of up to in equatorial summer. The wide range in temperatures is due to the thin atmosphere which cannot store much solar heat, the low atmospheric pressure, and the low thermal inertia of Martian soil. The planet is 1.52 times as far from the Sun as Earth, resulting in just 43% of the amount of sunlight.


title: Mars

text: If Mars had an Earth-like orbit, its seasons would be similar to Earth's because its axial tilt is similar to Earth's. The comparatively large eccentricity of the Martian orbit has a significant effect. Mars is near perihelion when it is summer in the Southern Hemisphere and winter in the north, and near aphelion when it is winter in the Southern Hemisphere and summer in the north. As a result, the seasons in the Southern Hemisphere are more extreme and the seasons in the northern are milder than would otherwise be the case. The summer temperatures in the south can be warmer than the equivalent summer temperatures in the north by up to .


title: Mars

text: Mars has the largest dust storms in the Solar System, reaching speeds of over . These can vary from a storm over a small area, to gigantic storms that cover the entire planet. They tend to occur when Mars is closest to the Sun, and have been shown to increase the global temperature.


title: Mars

text: Mars's average distance from the Sun is roughly , and its orbital period is 687 (Earth) days. The solar day (or sol) on Mars is only slightly longer than an Earth day: 24 hours, 39 minutes, and 35.244 seconds. A Martian year is equal to 1.8809 Earth years, or 1 year, 320 days, and 18.2 hours.


title: Mars

text: The axial tilt of Mars is 25.19° relative to its orbital plane, which is similar to the axial tilt of Earth. As a result, Mars has seasons like Earth, though on Mars they are nearly twice as long because its orbital period is that much longer. In the present day epoch, the orientation of the north pole of Mars is close to the star Deneb.


title: Mars

text: Mars has a relatively pronounced orbital eccentricity of about 0.09; of the seven other planets in the Solar System, only Mercury has a larger orbital eccentricity. It is known that in the past, Mars has had a much more circular orbit. At one point, 1.35 million Earth years ago, Mars had an eccentricity of roughly 0.002, much less than that of Earth today. Mars's cycle of eccentricity is 96,000 Earth years compared to Earth's cycle of 100,000 years.


title: Mars

text: Mars approaches Earth in a synodic period of 779.94 days. Earth orbits the Sun the closest to Mars's orbit around the Sun, and Mars orbit is the second closest to Earth after the orbit of Venus. Therefore, their closest approaches, the inferior conjunctions, are the second closest for Earth after those with Venus, and the closest for Mars to any other planet. The gravitational potential difference, and thus the delta-v needed to transfer between Mars and Earth is the second lowest for Earth and the lowest for Mars to any other planet, while transfers can possibly be optimized with Venus flybys.


title: Mars

text: During the late nineteenth century, it was widely accepted in the astronomical community that Mars had life-supporting qualities, including the presence of oxygen and water. However, in 1894 W. W. Campbell at Lick Observatory observed the planet and found that "if water vapor or oxygen occur in the atmosphere of Mars it is in quantities too small to be detected by spectroscopes then available". That observation contradicted many of the measurements of the time and was not widely accepted. Campbell and V. M. Slipher repeated the study in 1909 using better instruments, but with the same results. It wasn't until the findings were confirmed by W. S. Adams in 1925 that the myth of the Earth-like habitability of Mars was finally broken. However, even in the 1960s, articles were published on Martian biology, putting aside explanations other than life for the seasonal changes on Mars. Detailed scenarios for the metabolism and chemical cycles for a functional ecosystem were being published as late as 1962.


title: Mars

text: The current understanding of planetary habitabilitythe ability of a world to develop environmental conditions favorable to the emergence of lifefavors planets that have liquid water on their surface. Most often this requires the orbit of a planet to lie within the habitable zone, which for the Sun is estimated to extend from within the orbit of Earth to about that of Mars. During perihelion, Mars dips inside this region, but Mars's thin (low-pressure) atmosphere prevents liquid water from existing over large regions for extended periods. The past flow of liquid water demonstrates the planet's potential for habitability. Recent evidence has suggested that any water on the Martian surface may have been too salty and acidic to support regular terrestrial life.


title: Mars

text: The environmental conditions on Mars are a challenge to sustaining organic life: the planet has little heat transfer across its surface, it has poor insulation against bombardment by the solar wind due to the absence of a magnetosphere and has insufficient atmospheric pressure to retain water in a liquid form (water instead sublimes to a gaseous state). Mars is nearly, or perhaps totally, geologically dead; the end of volcanic activity has apparently stopped the recycling of chemicals and minerals between the surface and interior of the planet.


title: Mars

text: "In situ" investigations have been performed on Mars by the "Viking" landers, "Spirit" and "Opportunity" rovers, "Phoenix" lander, and "Curiosity" rover. Evidence suggests that the planet was once significantly more habitable than it is today, but whether living organisms ever existed there remains unknown. The "Viking" probes of the mid-1970s carried experiments designed to detect microorganisms in Martian soil at their respective landing sites and had positive results, including a temporary increase of production on exposure to water and nutrients. This sign of life was later disputed by scientists, resulting in a continuing debate, with NASA scientist Gilbert Levin asserting that "Viking" may have found life. Tests conducted by the "Phoenix Mars" lander have shown that the soil has an alkaline pH and it contains magnesium, sodium, potassium and chloride. The soil nutrients may be able to support life, but life would still have to be shielded from the intense ultraviolet light. A 2014 analysis of Martian meteorite EETA79001 found chlorate, perchlorate, and nitrate ions in sufficiently high concentration to suggest that they are widespread on Mars. UV and X-ray radiation would turn chlorate and perchlorate ions into other, highly reactive oxychlorines, indicating that any organic molecules would have to be buried under the surface to survive.


title: Mars

text: Scientists have proposed that carbonate globules found in meteorite ALH84001, which is thought to have originated from Mars, could be fossilized microbes extant on Mars when the meteorite was blasted from the Martian surface by a meteor strike some 15 million years ago. This proposal has been met with skepticism, and an exclusively inorganic origin for the shapes has been proposed. Small quantities of methane and formaldehyde detected by Mars orbiters are both claimed to be possible evidence for life, as these chemical compounds would quickly break down in the Martian atmosphere. Alternatively, these compounds may instead be replenished by volcanic or other geological means, such as serpentinite. Impact glass, formed by the impact of meteors, which on Earth can preserve signs of life, has also been found on the surface of the impact craters on Mars. Likewise, the glass in impact craters on Mars could have preserved signs of life, if life existed at the site.


title: Mars

text: Mars has two relatively small (compared to Earth's) natural moons, Phobos (about in diameter) and Deimos (about in diameter), which orbit close to the planet. The origin of both moons is unclear, although a popular theory states that they were asteroids captured into Martian orbit.


title: Mars

text: Both satellites were discovered in 1877 by Asaph Hall and were named after the characters Phobos (the deity of panic and fear) and Deimos (the deity of terror and dread), twins from Greek mythology who accompanied their father Ares, god of war, into battle. Mars was the Roman equivalent to Ares. In modern Greek, the planet retains its ancient name "Ares" (Aris: "Άρης").


title: Mars

text: From the surface of Mars, the motions of Phobos and Deimos appear different from that of the Earth's satellite, the Moon. Phobos rises in the west, sets in the east, and rises again in just 11 hours. Deimos, being only just outside synchronous orbitwhere the orbital period would match the planet's period of rotationrises as expected in the east, but slowly. Because the orbit of Phobos is below synchronous altitude, tidal forces from Mars are gradually lowering its orbit. In about 50 million years, it could either crash into Mars's surface or break up into a ring structure around the planet.


title: Mars

text: The origin of the two satellites is not well understood. Their low albedo and carbonaceous chondrite composition have been regarded as similar to asteroids, supporting a capture theory. The unstable orbit of Phobos would seem to point toward a relatively recent capture. But both have circular orbits, near the equator that is unusual for captured objects and the required capture dynamics are complex. Accretion early in the history of Mars is plausible, but would not account for a composition resembling asteroids rather than Mars itself, if that is confirmed.


title: Mars

text: A third possibility for their origin as satellites of Mars is the involvement of a third body or a type of impact disruption. More-recent lines of evidence for Phobos having a highly porous interior, and suggesting a composition containing mainly phyllosilicates and other minerals known from Mars, point toward an origin of Phobos from material ejected by an impact on Mars that reaccreted in Martian orbit, similar to the prevailing theory for the origin of Earth's satellite. Although the visible and near-infrared (VNIR) spectra of the moons of Mars resemble those of outer-belt asteroids, the thermal infrared spectra of Phobos are reported to be inconsistent with chondrites of any class. It is also possible that Phobos and Deimos are fragments of an older moon, formed by debris from a large impact on Mars, and then destroyed by a more recent impact upon the satellite.


title: Mars

text: Mars may have yet-undiscovered moons, smaller than in diameter, and a dust ring is predicted to exist between Phobos and Deimos.


title: Mars

text: Phobos is Synchronously orbiting Mars, where the same face stays facing the planet at ~6,028 km above the Martian surface. A space elevator could extend down from Phobos to Mars 6,000 km, about 28 kilometers from the surface, and just out of the atmosphere of Mars. A similar space elevator cable could extend out 6,000 km the opposite direction that would counterbalance Phobos. In total the space elevator would extend out over 12,000 km which would be below Areostationary orbit of Mars (17,032 km). A rocket launch would still be needed to get the rocket and cargo to the beginning of the space elevator 28 km above the surface. The surface of Mars is rotating at 0.25 km/s at the equator and the bottom of the space elevator would be rotating around Mars at 0.77 km/s, so only 0.52 km/s of Delta-v would be needed to get to the space elevator. Phobos orbits at 2.15 km/s and the outer most part of the space elevator would rotate around Mars at 3.52 km/s.


title: Mars

text: Dozens of crewless spacecraft, including orbiters, landers, and rovers, have been sent to Mars by the Soviet Union, the United States, Europe, India, the United Arab Emirates, and China to study the planet's surface, climate, and geology. NASA's "Mariner 4" was the first spacecraft to visit Mars; launched on 28 November 1964, it made its closest approach to the planet on 15 July 1965. "Mariner 4" detected the weak Martian radiation belt, measured at about 0.1% that of Earth, and captured the first images of another planet from deep space.


title: Mars

text: Once spacecraft visited the planet during NASA's Mariner missions in the 1960s and 1970s, many previous concepts of Mars were radically broken. After the results of the "Viking" life-detection experiments, the hypothesis of a hostile, dead planet was generally accepted. The data from "Mariner 9" and "Viking" allowed better maps of Mars to be made, and the "Mars Global Surveyor" mission, which launched in 1996 and operated until late 2006, produced complete, extremely detailed maps of the Martian topography, magnetic field and surface minerals. These maps are available online at websites including Google Mars. Both the "Mars Reconnaissance Orbiter" and "Mars Express" continued exploring with new instruments and supporting lander missions. NASA provides two online tools: Mars Trek, which provides visualizations of the planet using data from 50 years of exploration, and Experience Curiosity, which simulates traveling on Mars in 3-D with "Curiosity".


title: Mars

text: , Mars is host to fourteen functioning spacecraft. Eight are in orbit": 2001 Mars Odyssey", "Mars Express", "Mars Reconnaissance Orbiter", "MAVEN", "ExoMars Trace Gas Orbiter", the "Hope" orbiter, and the "Tianwen-1" orbiter. Another six are on the surface: the "InSight" lander, the Mars Science Laboratory "Curiosity" rover, the "Perseverance" rover, the "Ingenuity" helicopter, the "Tianwen-1" lander, and the "Zhurong" rover.