Extraterrestrial Life - Extraterrestrial Life Form

Extraterrestrial Life
Scientific life originating outside the earth , its basis and controversies.

Extraterrestrial Life

Have you ever thought about life outside the earth? Have you ever wondered about life in the other planets? We feel perplexed and excited when there are talks of extraterrestrial life. Hollywood has successfully exploited the theme of extraterrestrial life, making huge profits in the process. Although debates on extraterrestrial life have generated a great deal of controversy, acknowledgement of the extraterrestrial life could have a profound impact on our lives. But, the topic of extraterrestrial life has also evoked ridicule. Beware of those who swear on sighting UFO s for the sake of popularity. Do you tease your friend, calling him an "alien"? Well, you are actually complimenting him as aliens are said to operate with a superior technology. This aspect stirs curiosity among scientists.

Basis of Extraterrestrial Life

Have you heard of speculations regarding the extraterrestrial life? Would it look like a humanoid, a monster or is perhaps green in color? Extraterrestrial life forms are referred to as aliens. It is widely believed that silicon and ammonia could provide a basis for extraterrestrial life.

Silicon-based Life: Many scientists do not accept the argument of silicon-based life. Both carbon and silicon form long chains of polymers. Carbon can form methane whereas silicon can form silane. Note that silicon could not be easily used for respiration. Silicon does not give rise to components that exhibit chirality, which is essential for the functioning of enzymes. Astronomers do feel that silicon-based life is highly unlikely. Complex silicon-based molecules have seldom been observed in space whereas carbon-based compounds are abundant in space.

Ammonia-based Life: An ammonia solution could cause numerous chemical reactions and liquid ammonia is said to have chemical similarities with water. Ammonia not only dissolves organic molecules but also elemental metals. These chemical indications point out that ammonia-based life forms may actually exist.

Scientists constantly search for evidence of extraterrestrial life by analyzing the surface of mars and examining meteors that have fallen to earth. There are projects like SETI, conducting a search for radioactivity that would conform the presence of extraterrestrial life.

Searching for Extraterrestrial Life

Remote sensing helps in searching for extraterrestrial life. Robotic sampling missions may also be attempted. After the landing zone is selected, rovers could be used to deliver samplers closer to the best locations. Spacecrafts used to search for extraterrestrial lives are sterilized as they could contaminate extraterrestrial locales with earth organisms. But, note that the degree of sterilization varies and are mission-specific. Research by several groups suggests that meteorites from other planets contain amino acid analogs that are common among the earth's living things.

Controversies Regarding Extraterrestrial Life

The subject of extraterrestrial life has had its' own share of controversies. A play by Orson Wells in 1938 pressed the panic buttons everywhere. The play dealt with an invasion from mars. There were suggestions that the evidence of extraterrestrial life should be withheld from the public in order to avoid panic. But, some people do argue of selfish motives behind withholding information. It is alleged that the US government has secretly withheld information about the extraterrestrial life as it seeks a technological edge over other countries by duplicating the alien technology. There are also doubts as to the origin of the UFOs. Well, if the UFOs are of extraterrestrial origin, space agencies are definitely guarding the secret.

Scientists from NASA do believe that a primitive from of life might have existed about 4 billion years ago. It is believed that these life forms are very small and resemble the earth's bacteria. At present, scientists doubt life in mars, but they do not vehemently dismiss the idea.
