For the last several years, scientists have been discovering new planets elsewhere in the universe at an astonishing rate. Now a group of researchers who have surveyed a large group of stars similar to our own Sun say that potentially life-supporting rocky planets may in fact be extremely common in the Milky Way, circling anywhere from 20 percent to 60 percent of Sun-like stars.
Using the Spitzer Space Telescope, the researchers looked for signs of hot dust at distances plausible for planet formation around various stars, categorized by age.
They found that warm dust at that distance was relatively common around stars that were 10 million to 20 million years old, but that it fell off almost entirely by the time stars were about 300 million years old.
That's about the right time scale to correspond with the time the Earth and other planets are believed to have formed slowly through the collision of smaller bodes, out of the Sun's own dust cloud. Here's
University of Arizona astronomer Michael Meyer, who led the study:
A separate study found dust that some believe is attributable to the process of planet formation around stars that were just 10 million to
30 million years old.
The data can be interpreted different ways. At worst, it appears to show that at least one out of five Sun-like stars has the potential for forming rocky planets, they said. An optimistic interpretation might be that some massive discs of dust would form planets more quickly – and in that case, up to 62 percent of stars could be planet-forming.
But either way, the data seems to show there are plenty of other planets out there.
A paper on the conclusions appeared in the Feb. 1 issue of Astrophysical Journal Letters
Many, Perhaps Most, Nearby Sun-Like Stars May Form Rocky Planets [NASA JPL]
(Image: A parade of planets? Credit: NASA/JPL-Caltech)
