With the upcoming launch in
March 5th 2009 of the
Kepler mission to find extrasolar planets, there is quite a lot of buzz about the possibility of finding habitable planets outside of our Solar System. Kepler will be the first satellite telescope with the capability to find Earth-size and smaller planets. At the most recent meeting of the American Association for the Advancement of Science (AAAS) in Chicago, Dr. Alan Boss is quoted by numerous media outlets as saying that there could be billions of Earth-like planets in the Milky Way alone, and that we may find an Earth-like planet orbiting a large proportion of the stars in the Universe.
"There are something like a few dozen solar-type stars within something like 30 light years of the sun, and I would think that a good number of those — perhaps half of them would have Earth-like planets. So, I think there's a very good chance that we'll find some Earth-like planets within 10, 20, or 30 light years of the Sun," Dr. Boss said in an AAAS
podcast interview.
Dr. Boss is an astronomer at the Carnegie Institution of Washington Department of Terrestrial Magnetism, and is the author of
The Crowded Universe, a book on the likelihood of finding life and habitable planets outside of our Solar System.
This sort of postulation about the existence of extraterrestrial life (and intelligence) falls under the paradigm of the
Drake Equation, named after the astronomer Frank Drake. The Drake Equation incorporates all of the variables one should take into account when trying to calculate the number of technologically advanced civilizations elsewhere in the Universe. Depending on what numbers you put into the equation, the answer ranges from zero to trillions. There is
wide speculation about the existence of life elsewhere in the Universe.
The speculation by Dr. Boss and others will be put to the test later this year when the Kepler satellite gets up and running. Set to launch on March 5th 2009, the Kepler mission will utilize a 0.95 meter telescope to view one section of the sky containing over 100,000 stars for the entirety of the mission, which will last at least 3.5 years.
The Milky Way From Earth
[click to view larger image]
If you look up into the night sky on a very clear night, in an area with very little light pollution, you will see a band of stars splashed across the sky. That band is the Milky Way, the spiral galaxy in which our Solar System lies, and where almost every object you can see with your naked eye calls home.
The Solar System is inside the disk of the Milky Way, and orbits in one of the spiral arms at 26,000 light years from the center of the galaxy. We can't see the spiral structure of the galaxy from our planet because we are inside the disk and have no means of taking images from above or below the galaxy. Images of the Milky Way's spiral structure are created from computer modeling based on information from stars as they orbit the galaxy.
Much of the Milky Way is invisible to us because we have to look through the plane of its disk - a lot of the Milky Way is on the other side of the galaxy, and there is so much dust and so many bright stars closer to us that we can't see the stars behind all of this matter. Of the 5,000 to 8,000 stars in the Milky Way visible to the human eye from Earth, one can usually only see about 2,500 at a time. In fact, the few thousand stars we
can see of the Milky Way with our naked eye are only about 0.000003% of the 200-400 billion stars that inhabit the spiral.
Source: BBCNASA: http://www.nasa.gov/mission_pages/kepler/main/index.html--
Sam
