NASA’s Roman Could Find 400 Earth-Mass Rogue Planets

[efaardvark]

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“We estimate that our galaxy is home to 20 times more rogue planets than stars – trillions of worlds wandering alone,” said David Bennett, a senior research scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and a co-author of two papers describing the results. “This is the first measurement of the number of rogue planets in the galaxy that is sensitive to planets less massive than Earth.”

Full article here (nasa.gov).

This is something that I've been thinking for a while now, ever since Mike Brown at Caltech started coming out with his data on dwarf planets in our own solar system. We have already observed hundreds of potential dwarf planets there, and given the difficulty of making such observations and the fact that the volume of the space we're talking about there is so huge then there may very well be thousands of such planets, many of them Mars-sized or even larger.

Thing is, at such huge distances from the sun the orbits of those planets are only very loosely coupled to our star. Even here in the inner system there is ample evidence that the orbits of even Jupiter, the largest planet, have been disturbed at some point(s) in the solar system's history.  It would not take very much of a disturbance to knock planets both 100s of times smaller and further from the sun than Jupiter loose entirely and turn them into rogues.  Over the billions of years our solar system has wandered the galaxy there must have been many opportunities for such disruptions. It may even be that -most- of the planetary real estate in space is not in orbit around a star.

It will be very interesting to see what Roman comes up with.  Before Kepler we only knew of a few extrasolar planets.  Kepler found thousands more, but its search method could only find planets orbiting stars.  (And even then it was biased towards very large planets.)  Roman gives us a whole new method for finding extrasolar planets.  I can hardly wait to see what it can tell us.

Edit:  Here's a 'tubie on the same subject..

 

Edited July 23, 2023 by efaardvark