A NEWLY discovered rogue planet without a host star like the sun to orbit around has been detected dashing through space on its lonesome.
These planets – also known as free-floating planets – are practically invisible because they have no star sunlight reflecting on them and no light of their own.
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3 Artist’s impression of a rogue planet hurtling through spaceCredit: J. Skowron / OGLE
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3 A special technique allows scientists to detect them for a very brief periodCredit: J. Skowron / OGLE
Although they’re currently impossible to see, astronomers estimate that there could be billions of them in the Milky Way.
The first was only detected 25 years ago.
It’s thought such planets are initially born around stars but are kicked out later due to gravitational upheavals.
This can happen due to interactions with neighbouring planets or unstable stellar companions.
In a newly reported case, the speed at which a rouge planet is travelling has led experts to believe it may have been ejected by one of its original host stars.
And scientists have been able to figure out a direct measurement of its mass and distance from Earth too.
Astronomers use a telltale trick called gravitational microlensing to hunt out elusive rogue planets in space.
This is only possible when a rogue planet passes exactly between Earth and a distant star in the background.
Light from the star is bent, briefly exposing the planet to astronomers.
But this time two different observations were made, using several ground-based surveys here on Earth and another by the Gaia space telescope located 1.5million km away.
Tiny differences in the timing of the light reaching these distantly separated vantage points allowed scientists to gain some extra insight.
Firstly, the size.
This rogue planet is thought to be about 22 per cent that of Jupiter, the biggest planet in our solar system.
Secondly, the distance – and it’s considerably far.
It’s estimated to be about 10,000 light-years away from us, toward the centre of our galaxy.
Scientists are hoping to detect and learn more about rogue planets in the coming years with Nasa‘s brand new Nancy Grace Roman Space Telescope, which is due to launch into space in May 2027.
It’ll have a field of view at least 100 times larger than the Hubble Space Telescope that’s been in use since 1990, potentially measuring light from a billion galaxies in its lifetime.
The findings were led by Professor Subo Dong from the National Astronomical Observatories, Chinese Academy of Sciences and published in the Science journal.
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