Cosmic census estimates 50 billion planets in our galaxy
February 21st, 2011 - 11:29 am ICT by IANSLondon, Feb 21 (IANS) A cosmic census conducted for the first time has revealed that there are at least 50 billion planets in our Milky Way galaxy.And some 500 million of those planets are in what is known as the Goldilocks zone, where the climate is thought to be not-too-hot and not-too-cold, and life could exist, Daily Mail reported Sunday.
The numbers were extrapolated from the early results of NASA’s Kepler telescope following a three-and-a-half year mission, which has cost about $600 million.
Kepler science chief William Borucki says scientists took the number of planets they found in the first year of searching a small part of the night sky and then made an estimate on how likely stars are to have planets. Kepler spots planets as they pass between Earth and the star it orbits.
So far Kepler has found 1,235 candidate planets, with 54 in the Goldilocks zone, where life could possibly exist.
Kepler’s main mission is not to examine individual worlds, but give astronomers a sense of how many planets, especially potentially habitable ones, there are likely to be in our galaxy.
They would use the one-four-hundredth of the night sky that Kepler is looking at and extrapolate from there, the newspaper said.
Borucki and colleagues figured one of two stars has planets and one of 200 stars has planets in the habitable zone. They announced these ratios Saturday at the American Association for the Advancement of Science annual conference in Washington.
And that’s a minimum because these stars can have more than one planet and Kepler has yet to get a long enough glimpse to see planets that are further out from the star, like Earth, Borucki said.
For example, if Kepler were 1,000 light years from Earth and looking at our sun and noticed Venus passing by, there’s only a one-in-eight chance that Earth would also be seen, astronomers said.
To get the estimate for the total number of planets, scientists then took the frequency observed already and applied it to the number of stars in the Milky Way.
For many years scientists figured there were 100 billion stars in the Milky Way, but last year a Yale scientist figured the number was closer to 300 billion stars. And that’s just our galaxy. Scientists figure there are 100 billion galaxies.
Borucki said the new calculations lead to worlds of questions about life elsewhere in the cosmos.
- 50bn planets in Milky Way, estimates first cosmic census - Feb 21, 2011
- NASA finds 1,235 planets that could have extra-terrestrial lifeforms - Mar 30, 2011
- Earth-like planet found - Dec 06, 2011
- Kepler telescope finds new planetary system - Aug 27, 2010
- Scientists discover first Earth-Size planets outside the Milky Way - Dec 21, 2011
- Kepler Mission discovers 700 new planets - Jul 26, 2010
- Nasa space telescope spots odd new solar system - Feb 03, 2011
- NASA Finds 2 New Planets In Milky Way - Aug 27, 2010
- Kepler camera launched: Other "earths", where are you? - Mar 07, 2009
- Web users locate two new potential planets - Sep 22, 2011
- Billions of life bearing planets float in the milky way - May 14, 2012
- ET, where are you? NASA to launch Kepler camera - Feb 20, 2009
- Earth-sized planets found beyond solar system - Dec 21, 2011
- Five more exoplanets found in Milky Way - Jan 05, 2010
- Kepler 10b planet discovered - Jan 12, 2011
Tags: american association for the advancement of science, association for the advancement of science, borucki, candidate planets, chief william, daily mail, glimpse, habitable zone, half year, kepler, light years, london feb, milky way galaxy, nasa, night sky, number of planets, orbits, ratios, telescope, two stars