Scientists have found about 4,000 exoplanets and a few rogue planets but a recent finding has left them surprised.
The Kepler mission, specifically created to study the Milky Way for planets beyond our Solar System, stopped collecting data two years ago. While that's a feat in itself, Kepler's estimate shows that there are many planets out there that haven't yet been identified - and one of them could be humanity's next home.
Given the fact that rogue planets don't emit light like stars, or even enough heat to be visible in infrared light, these otherwise invisible worlds can be seen through microlensing events.
They used a technique called microlensing for discovering this planet, and this technique allows them to find planets that they otherwise wouldn't be able to. "The chances of observing microlensing are very slim, because the three objects, the source, the lens and the observer, must be nearly exactly aligned".
The researchers described in a statement that this phenomenon "acts like a giant magnifying glass", making it easier to observe distant objects.
'[The] chances of observing microlensing are extremely slim because three objects - source, lens and observer - must be almost perfectly aligned, ' said paper author and astronomer Przemek Mroz of the California Institute of Technology.
Every night, the 1.3-meter OGLE survey telescope in Warsaw scans the center of the Milky Way, which contains hundreds of millions of stars, looking for changes in the brightness of the stars. Now using a telescope at Las Campanas Observatory in Chile, the astronomers look to the galaxy's center on clear nights, in search of changes in the brightness of stars.
These were the details of the news.
The 28-year project is responsible for several previous rogue planet discoveries, but the latest is the smallest ever detected.
It's also worth noting that the original news has been posted and is available at saudi24news. The more massive the lens object is, the longer the microlens event takes. "If the lens were orbiting a star, we would detect its presence in the light curve of the event" - adds dr Poleski. With a mass somewhere in-between that of the Earth and Mars, the planet is thought to be the smallest of its kind to have been discovered.
The researchers believe that the event was caused by a planet smaller than Earth, and possibly around the size of Mars. Where most microlensing events last a few days, this one - designated OGLE-2016-BLG-1928 - lasted just 42 minutes, indicating an extremely tiny object.
The new exoplanet, the smallest free-floating planet astronomers have found, is too small to be directly observed.
'We can rule out the planet having a star within about eight astronomical units'. Other information, such as its chemical composition or temperature, can not be known at this time owing to astronomical limitations.