This is not a NASA Website. You might learn something. It's YOUR space agency. Get involved. Take it back. Make it work - for YOU.
Space & Planetary Science

Planets Are Common – Everywhere

By Keith Cowing
NASA Watch
January 11, 2012
Filed under , ,

The Milky Way Contains At Least 100 Billion Planets According to Survey
“Our Milky Way galaxy contains a minimum of 100 billion planets according to a detailed statistical study based on the detection of three extrasolar planets by an observational technique called microlensing. Kailash Sahu, of the Space Telescope Science Institute in Baltimore, Md., is part of an international team reporting today that our galaxy contains a minimum of one planet for every star on average. This means that there should be a minimum of 1,500 planets within just 50 light-years of Earth.”
A Wealth of Habitable Planets in the Milky Way
“Our results show that planets orbiting around stars are more the rule than the exception. In a typical solar system approximately four planets have their orbits in the terrestrial zone, which is the distance from the star where you can find solid planets. On average, there are 1.6 planets in the area around the stars that corresponds to the area between Venus and Saturn.”
Kepler Discovery Establishes New Class of Planetary Systems
“Using data from NASA’s Kepler Mission, astronomers announced the discovery of two new transiting “circumbinary” planet systems — planets that orbit two stars. This work establishes that such “two sun” planets are not rare exceptions, but are in fact common with many millions existing in our Galaxy.”
Discovery of the Smallest Exoplanets: The Barnard’s Star Connection
“The discovery of the three smallest planets yet orbiting a distant star, which was announced today at the annual meeting of the American Astronomical Society, has an unusual connection to Barnard’s star, one of the Sun’s nearest neighbors. .. The team used data from NASA’s Kepler mission combined with additional observations of a single star, called KOI-961, to determine that it possesses three planets that range in size from 0.57 to 0.78 times the radius of Earth. This makes them the smallest of the more than 700 exoplanets confirmed to orbit other stars.”

NASA Watch founder, Explorers Club Fellow, ex-NASA, Away Teams, Journalist, Space & Astrobiology, Lapsed climber.

5 responses to “Planets Are Common – Everywhere”

  1. Marc Boucher says:
    0
    0

    I wonder what Peter Ward and Donald Brownlee who wrote Rare Earth in 2000 would say now? The same thing or would they revise their conclusion.

    • Chlopiec Do Bicia says:
      0
      0

      I don’t think so. They were clearly motivated to prove that there are no other multi-celluar animals (so intelligent animals too) in galaxy. Anyway REH is already dead in water, and we did not yet start any serious spectroscopy on smaller worlds!

  2. samskuce says:
    0
    0

    Is 100 billion enough to generate another advanced civilization?  I don’t think it’s unreasonable to plug numbers in the Drake equation so that only one planet in every one million gets life, only one in one million of those with life gets an advanced civilization, and you’ve already gone below one chance in 100 billion, making us an outlier.

    I think the one in a million chance that a planet develops life is perhaps pessimistic, since Kepler-22b was found pretty quickly, but I really do think that the one in a million chance that microbes eventually yield spacefaring spam could be a valid estimate.  There are lots of variables there.   For example, there was talk recently of having to extend the Kepler mission because it turns out that the stars in the target region are a lot more intrinsically variable in their output than we expected, which implies that our sun could be unusual simply in the stability of its output.  An unstable star is probably not the best host for a sustained population of land animals, although amoeba-types might not even notice it from their watery domain.

  3. nasa817 says:
    0
    0

    My simplified version of the Drake equation.  Planets are common, of that I’m sure.  Habitable planets are plentiful, no doubt.  Life does exist elsewhere in our galaxy, more likely than not.  Intelligent life is not unique to Earth in the Milky Way, a strong possibility.

    If you believe in evolution, the odds that 100 billion planets would yield a habitable planet with intelligent life are pretty damned good.  1:100,000,000,000 are extremely, extremely long odds.  If you believe in creationism, why would God create 100 billion planets in our galaxy and populate only one of them?