Rocky, roughly earth-like planets orbiting stars seem to be the rule, rather than the exception, an new study reveals.
Alien planets are incredibly common in our Milky Way galaxy, outnumbering stars by a large margin, a new study suggests.
On average, each of the 100 billion or so stars in our galaxy hosts at least 1.6 planets, according to the study, bringing the number of likely alien worlds to more than 160 billion. And large numbers of these exoplanets are likely to be small and rocky — roughly Earth-like — since low-mass planets appear to be much more abundant than large ones.
"This statistical study tells us that planets around stars are the rule, rather than the exception," said study lead author Arnaud Cassan of the Paris Institute of Astrophysics. "From now on, we should see our galaxy populated not only with billions of bright stars, but imagine them surrounded by as many hidden extrasolar worlds."
The vast majority of these exoplanet detections have been made using two different techniques: transit photometry and radial velocity. [Gallery: The Strangest Alien Planets]
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