Scientists Discover Earth-Sized Rogue Planet Floating In The Milky Way

On Nov 01

London: Scientists have discovered in the Milky Way an Earth-sized free-floating rogue planet which does not orbit any star.

Rogue planets are a bit uncommon as although many of the known exoplanets discovered so far do not resemble those in our solar system, they have one thing in common — they all orbit a star.

However, theories of planet formation and evolution predict the existence of free-floating (rogue) planets, gravitationally unattached to any star.

Polish astronomers from the Astronomical Observatory of the University of Warsaw provided the first evidence for the existence of such planets in the Milky Way a few years ago.

However, the newly-detected planet, detailed in the Astrophysical Journal Letters, is the smallest rogue world ever found, according to the scientists.

“Our discovery demonstrates that low-mass free-floating planets can be detected and characterised using ground-based telescopes,” said study co-author Andrzej Udalski, Professor at University of Warsaw in Poland.

Exoplanets can be only rarely directly observed. Usually, astronomers find planets using observations of the light from the planet’s host star.

For example, if a planet crosses in front of its parent star’s disk, then the observed brightness of the star periodically drops by a small amount causing so called transits.

Astronomers can also measure the motion of the star caused by the planet.

Free-floating planets emit virtually no radiation and — by definition — they do not orbit any host star, so they cannot be discovered using traditional methods of astrophysical detection.