This could rewrite the solar system's map.
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This is an image of Ceres, the nearest dwarf planet to Earth
in the solar system. A new dwarf planet extremely far from the sun may have
just been discovered. Credit: NASA / JPL-Caltech / UCLA / MPS / DLR / IDA |
Just when you thought you knew all the worlds in the solar
system, astronomers go and discover a new object that could rewrite the space
map.
This icy world, temporarily named 2017 OF201, could be a
distant cousin of Pluto — and scientists mean "distant" quite
literally. At its farthest point, it's more than 1,600 times the distance of
Earth from the sun. At its closest, it's still 44.5 times farther than Earth.
What makes 2017 OF201 stand out is its very stretched-out
path around the sun, which takes an incredible 25,000 Earth-years to complete.
For comparison, Pluto makes a lap around the sun every 248 Earth-years.
How this world got to the edge of the solar system is a
mystery — perhaps the result of close encounters with a giant planet like
Jupiter or Neptune that tossed it out into a wide orbit. Or maybe when it was
originally ejected, it ended up in the so-called Oort Cloud before returning.
The Oort Cloud is thought to be a sphere of ancient, icy objects surrounding
the solar system. NASA says the cloud remains a theory because the comets there
have been too faint and distant to be directly observed.
The International Astronomical Union’s Minor Planet Center,
which catalogs new moons and other small bodies in the solar system, announced
the discovery on May 21. At roughly 435 miles wide, 2017 OF201 could qualify as
a dwarf planet, the same designation Pluto has had since its demotion from
ninth planet in 2006.
"Even though advances in telescopes have enabled us to
explore distant parts of the universe," said Sihao Cheng, the Institute
for Advanced Study researcher who led the discovery, in a statement,
"there is still a great deal to discover about our own solar system."
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A composite image displays the five recognized dwarf planets
in the solar system, as well as the new candidate 2017 OF201. Credit: NASA /
JPL-Caltech / Sihao Cheng et al. infographic |
Cheng, along with Princeton University graduate students,
found the possible dwarf planet while searching for a potential "Planet
9," a hypothetical hidden world whose gravitational effects could be
responsible for a strange clustering of far-flung objects beyond Neptune.
The team used computer programs to look through years of
space pictures taken by the Victor M. Blanco Telescope in Chile and the Canada
France Hawaii Telescope. By connecting bright spots that moved slowly across
the sky, they were able to identify it.
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These are the current orbits of Pluto, Neptune, and 2017
OF201. Credit: Jiaxuan Li / Sihao Cheng infographic |
But 2017 OF201 is a strange outlier because it doesn’t
follow the clustering pattern of other trans-Neptunian objects.
"The existence of 2017 OF201 might suggest that Planet 9 or X doesn't exist," said Jiaxuan Li, one of the collaborators, on his personal website. Their research is available now on the arXiv pre-print server.
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