Tuesday, November 27, 2007
History Channel: The Universe 2007 Premiere
Tonight, Nov. 26, the History Channel presented its season premier of The Universe, with the program "Alien Planets". The subject tonight was planets outside the solar system, in other systems mostly within 200 light years of earth.
Planets are discovered from the wobbles of their stars. A star and planets all revolve around a center of gravity, and even the star moves slightly.
The first planets to be found were "hot Jupiters" close to their parent stars, usually larger than Jupiter. Then other gas giants were found in highly elliptical orbits, resulting in extremely strong, hemisphere sized storms on the "planets."
Finally we started finding more earth-like planets. A planet with seven or so earth masses might be completely covered with water, and it might get so dense that at depths the water behaves like ice even though it is warm. (Neptune is said to be like this.) The show also discussed a planet near a red dwarf, which would be in the habitable zone at a much closer distance and cause an easier-to-detect wobble.
The show also presented a pulsar (neutron star) that actually had small rocky planets around it. Apparently after a supernova, there is still a small cloud left that can coalesce into new small planets. The pulsar from the planet's surface is a beacon or lighthouse, and quite deadly.
An earlier show from last season's Universe, with discussion of Venus with respect to global warming, is discussed on my "disaster movies" blog here.
Update: Jan. 8, 2007
"Alien Moons" discussed the mechanics of the moons of the solar system planets, with "irregular moons" mostly captured from outside the solar system, and "regular moons" usually larger and more spherical and in the same motion as the planet's rotation. Io, Europa and Triton (Neptune, irregular) were discussed in detail, but Titan (Saturn) was not. That's a disappointment, as Titan is the solar system's most interesting (and earth-like) moon. Probably it will be covered on a later program.