What’s the exact finding?
An article describing the findings, 'A Terrestrial-Mass Rogue Planet Candidate Detected in the Shortest-Timescale Microlensing Event’, has been published in Astrophysical Journal Letters. Such planets cannot be viewed using traditional techniques as they do not orbit around a sun and won’t get be spotted by the dimming they cause while crossing in front of stars besides this they don’t emit any radiation.
Such free-floating planets may have formed in the rotating discs of dense gas and dust around stars and may have moved away from their parent planetary systems because of gravitational interactions with other bodies.
Astronomers dig deep into these objects because it enables them to explore about the turbulent history of planetary systems including the Solar System. The researchers said the newly detected planet is the smallest rogue world ever found, with models hinting that the new planet may have a mass somewhere between Earth and Mars.
The particular findings could be one of many such rogue planets in the Milky Way, and scientists have suggested they may even outnumber the stars in our galaxy.
How do scientists observe them?
Scientists take advantage of an astronomical phenomenon known as "gravitational microlensing" to discover the planet, which makes itself visible by bending the light of more distant stars.
The result was an effect that is much like a giant magnifying glass, which brightens light from a background "source" star to reveal the presence of the massive object. Gravitational microlensing is only possible when an astronomer's telescope lies in almost perfect alignment with the observed object and the source star.
The researchers scrutinised data collected from microlensing surveys of the Galactic Bulge, which is the central part of the Milky Way. They used the 1.3-metre Warsaw Telescope at Las Campanas Observatory in Chile to gather the data.