In the June issue of Astronomy
, author Steve Nadis wrote “Do billions of rogue planets drift through space?” His story talks a great deal about a technique astronomers use called gravitational microlensing.
This NASA artist’s animation illustrates the technique used for finding free-floating Jupiter-mass planets in space. Astronomers think gravitational interactions ejected such worlds early on from their developing solar systems.Astronomy magazine subscribers can read the full column for free. Just make sure you're registered with the website.