Wednesday, June 24, 2009

PBS "Savage Planet": "Deadly Skies": Lightning, hail, and asteroids

PBS (Channel 13 in New York) has a new series called “Savage Planet”, with this home page. On Monday, June 22, WETA aired “Deadly Skies” (episode 3). The program focused on two major threats: cloud-to-ground lightning and hail in supercell thunderstorms, with a couple of storms in Sydney Australia (moving East to West) as examples, and meteor showers, particularly pieces of asteroids. It did not deal with tornadoes.

The program took the position that we map only a small fraction of the asteroids that could hit us. Once every few hundred thousand years, we take a hit (from a body over 1 km or so in diameter) that could wipe out civilization.

The show also takes the position that comets are even more dangerous than asteroids.
The last part of the show summarized the Shoemaker-Levy comet that hit Jupiter in 1994 (link). We wouldn’t be here if it weren’t for Jupiter, which protects Earth from most of the fragments that could hit it.

Attribution link for Wikimedia Commons NASA picture of the impact of Shoemaker-Levy on Jupiter, here.

Sunday, June 21, 2009

"Impact": What if a piece of a brown dwarf hit the Moon (or the Earth, for that matter)?

On Sunday, June 21, 2009, ABC aired the first two hours of its miniseries “Impact”, directed by Mike Rohl, written by Michael Vickerman, apparently financed and made in Germany and Canada. The second half airs June 28.

The movie opens with a meteor shower, with the Moon taking a huge hit from a large piece, in sight of a boy’s telescope. Soon there are odd effects around the world: the little boy shocks everyone with a tape measure home run in Little League, when the field is attacked by lightning in clear air. In fact, whole objects and people levitate, and irregular tsunamis occur around the world. (This film bears no relation to Dreamworks’s “Deep Impact” in 1998).

Astronomers notice that the Moon’s orbit is becoming elliptical, and approaching ever closer. Soon geologists recover a meteor fragment and find that it consists of the degenerate matter of a brown dwarf. The Moon is much too massive and has a piece of brown dwarf lodged inside it like a bullet needing to be removed by a 19th Century doctor in a western. It comes closer and closer, picking up whole trains, and will eventually collide with Earth.

The astronomers say that two brown dwarfs collided, but in fact I think that the chunks of degenerate matter would evaporate, so it sounds like this is impossible.

A rogue brown dwarf could threaten a planet directly, and it probably has happened in some solar systems in our galaxy.

Attribution link for a NASA public domain illustration of a T-dwarf. It actually would look magenta if close enough to be seen.

Update: June 28, 2009
ABC aired the second half (two hours) of the film tonight. They come up with a plan to split the Moon in two and eject the fragment of brown dwarf. And, yup, they have to send astronauts, and some scientist-not-so-spaceworthy, and yes, a man (with a pregnant wife, played up for sympathy) is "elected" for self-sacrifice. Well, maybe, like in Apollo 13, they can get them back, but they don't have Ron Howard directing. The special effects, including how the Moon looks from Earth when split into pieces, are interesting.

Attribution link for Wikimedia picture of Moon here.

Saturday, June 13, 2009

"The Seven Signs of the Apocalypse" on the History Channel












“Bible prophecy is like advanced intelligence.”

Tuesday, June 02, 2009

















