A mysterious tenth planet really may lie at the edge of the solar system, according to new research.
Astronomers have discovered an object two and a half times further from the Sun than Pluto that adds to evidence of the existence of ‘Planet X’.
It is one of the most distant bodies ever identified within the sun’s gravitational range.
And its unusual orbit supports the theory there is a huge, rocky world ten times bigger than Earth on the outskirts of our star system.
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A mysterious tenth planet really may lie at the edge of the solar system, according to new research. Astronomers have discovered an object two and a half times further from the Sun than Pluto that adds to evidence of the existence of ‘Planet X’ (artist’s impression)
WHAT IS PLANET X?
Astronomers believe that the orbits of a number of bodies in the distant reaches of the solar system have been disrupted by the pull of an as yet unidentified planet.
First proposed by a group at CalTech in the US, this alien world was theorised to explain the distorted paths seen in distant icy bodies.
In order to fit in with the data they have, this alien world – popularly called Planet Nine – would need to be roughly four time the size of Earth and ten times the mass.
Researchers say a body of this size and mass would explain the clustered paths of a number of icy minor planets beyond Neptune.
Its huge orbit would mean it takes between 10,000 and 20,000 years to make a single pass around the sun.
The theoretical Planet Nine is based on the gravitational pull it exerts on these bodies, with astronomers confident it will be found in the coming years.
Those hoping for theoretical Earth-sized planets proposed by astrologers or science fiction writers – which are ‘hiding behind the sun’ and linked with Doomsday scenarios – may have to keep searching.
Nicknamed ‘Planet Nine’, the idea first emerged in 2014 when Dr Scott Sheppard and Professor Chad Trujillo sought to explain a strange cluster of six small objects in the Kuiper Belt, a field of icy and rocky objects beyond Neptune.
Their orbits all tilted in the same way, an arrangement that is nearly impossible to generate without the help of some external force.
Dr Sheppard and Prof Trujillo suggested a large planet was lurking in the shadows, warping the orbits of objects that came near.
Now the same team has found a similar body whose orbit is being similarly affected. At about 300 km (186 miles) wide, it is on the small side of being a dwarf planet.
It is about 80 astronomical units (AU) from the Sun, a measurement defined as the distance between the Earth and Sun. For context, Pluto is around 34 AU.
Called 2015 TG387, it has a very elongated orbit meaning it never comes close enough to the Solar System’s giant planets, like Neptune and Jupiter, to have significant gravitational interactions with them.
Dr Sheppard, of Carnegie Institution of Science, said: ‘These distant objects are like breadcrumbs leading us to Planet X.
‘The more of them we can find, the better we can understand the outer Solar System and the possible planet that we think is shaping their orbits – a discovery that would redefine our knowledge of the Solar System’s evolution.’
Prof Trujillo, of Northern Arizona University, ran computer simulations for different hypothetical Planet X orbits that explained how 2015 TG387 would actually be shepherded by its gravity.
It never comes closer to the Sun, a point called perihelion, than about 65 AU.
Only two other objects, known as 2012 VP113 and Sedna at 80 and 76 AU respectively, have more-distant perihelia.
Dr Sheppard said: ‘These so-called Inner Oort Cloud objects like 2015 TG387, 2012 VP113, and Sedna are isolated from most of the Solar System’s known mass, which makes them immensely interesting.
Pictured is a predicted orbit of the new dwarf planet, nicknamed ‘the goblin’ (left). It never comes closer to the Sun, a point called perihelion, than about 65 AU. Only two other objects, known as 2012 VP113 and Sedna at 80 and 76 AU respectively, have more-distant perihelia
‘They can be used as probes to understand what is happening at the edge of our Solar System.’
The simulations showed why the most-distant objects in our Solar System have similar orbits that keep them from ever approaching the proposed planet too closely.
Prof Trujillo said: ‘What makes this result really interesting is that Planet X seems to affect 2015 TG387 the same way as all the other extremely distant Solar System objects.
‘These simulations do not prove that there’s another massive planet in our Solar System, but they are further evidence that something big could be out there.’
It follows research by mathematicians at Caltech who found the existence of a massive ninth planet was the only explanation for the sculpting of the orbits of these other, smaller objects.
The object was discovered as part of the team’s ongoing hunt for unknown dwarf planets and Planet X. It is the largest and deepest survey ever conducted for distant Solar System objects.
The mysterious object is one of the most distant bodies ever identified within the sun’s gravitational range
They first observed 2015 TG387 in October of 2015 at the Japanese Subaru 8-metre telescope located atop Mauna Kea in Hawaii.
Follow-up observations at the Magellan telescope at Carnegie’s Las Campanas Observatory in Chile and the Discovery Channel Telescope in Arizona were obtained in 2015, 2016, 2017 and 2018 to determine 2015 TG387’s orbit.
The location in the sky where 2015 TG387 reaches perihelion is similar to 2012 VP113, Sedna, and most other known extremely distant trans-Neptunian objects, suggesting that something is pushing them into similar types of orbits.
Its discovery was announced by the International Astronomical Union’s Minor Planet Centre in Washington DC.
A paper describing it has also been submitted to the Astronomical Journal.