Uranus 2.0: Strange blue world is discovered 25,000 light-years away - and it could explain how 'ice giants' form
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Astronomers have spotted a turbulent planet, 25,000 light-years away, that is four times as massive as Uranus.
The exoplanet is part of a double-star system known as OGLE-2008-BLG-092L around 19 times farther away from its parent star – the same distance as Uranus and the sun.
The alien Uranus may help scientists explain solve the mystery about the origins of the ice giants in our solar system.
Astronomers have spotted a turbulent planet, 25,000 light-years away, that is four times as massive as Uranus (pictured). The exoplanet is part of a double-star system known as OGLE-2008-BLG-092L around 19 times farther away from its parent star – the same distance as Uranus and the sun
Astronomers have discovered hundreds of planets around the Milky Way, including rocky planets similar to Earth and gas planets similar to Jupiter.
But there is a third type of planet in our solar system - part gas, part ice - and this is the first time anyone has spotted a twin for our so-called 'ice giant' planets, Uranus and Neptune.
While Uranus and Neptune are mostly composed of hydrogen and helium, they both contain significant amounts of methane ice, which gives them their bluish appearance.
Given that the newly discovered planet is so far away, astronomers can't tell anything about its composition, but its distance from its star suggests that it's an ice giant
The astronomers spotted the planet due to a phenomenon called gravitational microlensing—when the gravity of a star focuses the light from a more distant star and magnifies it like a lens. The light curve of the OGLE-2008-BLG-092 microlensing event is pictured
The newly discovered planet leads a turbulent existence: it orbits one star in a binary star system, with the other star close enough to disturb the planet's orbit.
The discovery was made by an international team led by Radek Poleski, a researcher at Ohio State University.
'Nobody knows for sure why Uranus and Neptune are located on the outskirts of our solar system, when our models suggest that they should have formed closer to the sun,' said Professor Andrew Gould at Ohio University.
'One idea is that they did form much closer, but were jostled around by Jupiter and Saturn and knocked farther out.'
'Maybe the existence of this Uranus-like planet is connected to interference from the second star,' he added.
'Maybe you need some kind of jostling to make planets like Uranus and Neptune.'
The binary star system lies in our Milky Way galaxy, in the direction of Sagittarius. The first star is about two thirds as massive as our sun, and the second star is about one sixth as massive.
The astronomers spotted the planet due to a phenomenon called gravitational microlensing—when the gravity of a star focuses the light from a more distant star and magnifies it like a lens.
Very rarely, the signature of a planet orbiting the lens star appears within that magnified light signal.
In this case, there were two separate microlensing events, one in 2008 that revealed the main star and suggested the presence of the planet, and one in 2010 that confirmed the presence of the planet and revealed the second star.
'We were lucky to see the signal from the planet, its host star, and the companion star,' said Professor Poleski.
'If the orientation had been different, we would have seen only the planet, and we probably would have called it a free-floating planet,' he added.
Both observations were done with the 4.2ft (1.3 metre) Warsaw Telescope at Las Campanas Observatory in Chile as part of the Optical Gravitational Lensing Experiment.
'Nobody knows for sure why Uranus and Neptune are located on the outskirts of our solar system, when our models suggest that they should have formed closer to the sun,' said Professor Andrew Gould at Ohio University. Artist's impression pictured
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