Astronomers: We think we're about to find 100 billion Earths

Looks like we're about to get one step closer to finding life on other worlds.

Finding planets is not easy work. In fact, it wasn't until 1995 that we first discovered a planet orbiting a Sun-like star. And we were really looking! Tracking down a small, non-luminous body (like Earth, for example) is exceedingly difficult because most planets get lost in the glare of the star they orbit. So we have to get inventive and find indirect ways of detecting heavenly bodies. Thankfully, scientists think they've nailed down a better way of doing just that.

This new strategy involves a combination of gravitational microlensing and use of NASA's Kepler space telescope. Researcher and lead author Dr. Phil Yock talks about the proposal this way:

Kepler finds Earth-sized planets that are quite close to parent stars, and it estimates that there are 17 billion such planets in the Milky Way. These planets are generally hotter than Earth, although some could be of a similar temperature (and therefore habitable) if they're orbiting a cool star called a red dwarf.

Our proposal is to measure the number of Earth-mass planets orbiting stars at distances typically twice the Sun-Earth distance. Our planets will therefore be cooler than the Earth. By interpolating between the Kepler and MOA (Microlensing Observations in Astrophysics) results, we should get a good estimate of the number of Earth-like, habitable planets in the Galaxy. We anticipate a number in the order of 100 billion.

While microlensing measures the deflection of light from distant stars on its way toward Earth, the Kepler telescope is able to measure loss of light from a star when a planet orbits between Earth and the star. So, basically, they tag-team together to make discovering Earth-type planets easier. And, yes, the estimated figure is that there may be as many as 100 billion planets similar to ours.

Microlensing has already been used to discover planets similar in size to Neptune and Jupiter. Dr. Yock and his colleagues now believe they will more easily be able to discover smaller, more Earth-like worlds by utilizing a worldwide network of moderate-sized robotic telescopes.

Does this mean we'll be finding new forms of life right away? Not quite. Says Yock, "... it will be a long way from measuring this number to actually finding inhabited planets, but it will be a step along the way."

But this is still good news for anyone who desperately dreams of a life out among the stars. If we're able to go from 1 to 100 billion Earths in under 20 years of study, just imagine what we'll do in another 50 years' time, or even sooner!

(via Royal Astronomical Society)

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