Scientists have identified
a new dwarf planet in our Solar System, and it’s lurking way out in the edges,
some 13.6 billion km (8.5 billion miles) from the Sun. The Iowa-sizedobject - for now known as 2014 UZ224 - takes 1,100 years to complete a
single orbit of the Sun, and could soon join the ranks of the five established
dwarf planets in the Solar System: Ceres, Eris, Haumea, Makemake, and most
famous of all, Pluto.
While only five dwarf
planets have been officially recognised in the Solar System, it’s thought that
there could be at
least 100 more lurking in the Kuiper Belt - a region beyond the orbit
of Neptune that’s thought to be teeming with comets, asteroids, and small
planetary bodies. Discovered by a team of
undergraduate students led by physicist David Gerdes from the University of
Michigan, 2014 UZ224 was pinpointed in an enormous map of galaxies created by a
project called the Dark Energy
Survey (DES).
To spot a Solar System
object in a massive map of several distant galaxies, you basically just have to
look for something that’s moving.
"Objects in the Solar
System, when you observe them at one instant and then a little while later,
they appear to be in a different place in the sky," Gerdestold Joe Palca at NPR.
The team then used
specialised computer software to connect the dots and confirm that what they
were looking at was a single object - something
that took years to figure out.
"We often just have a
single observation of the thing, on one night," saidGerdes. "And then two weeks later one observation, and then five
nights later another observation, and four months later another observation. So
the connecting-the-dots problem is much more challenging."
The discovery has now beenconfirmed by the International Astronomical Union, but whether or not
it will decide to let 2014 UZ224 join the ranks of the five established dwarf
planets in our Solar System is another matter.
Both 2014 UZ224, and the
other new dwarf planet was discovered in our Solar System backin July - called 2015 RR245 - technically pass the criteria for dwarf
planets, which describes an object that resembles a planet, but isn’t a planet.
The most important
distinction for a dwarf planet is that it’s large enough to have become round
due to its own gravitational attraction.
As notorious "Pluto
killer", Mike Brown - the California Institute of Technology astronomer
who successfully campaigned for Pluto to be downgraded to
a dwarf planet in 2006 - explains, we can pretty
much assume that anything larger than 400 km in diameter in the Kuiper belt is
round, and therefore could qualify as a dwarf planet.
2014 UZ224 is estimated to
have a diameter of around 530 km (329 miles).
But why do astronomers
care about round? Brownsays, the ability for an object to transition from an irregular shape to a
round one makes it more likely to have properties that astronomers will want to
study.
"Th[e] transition
from irregularly shaped to round objects is important in the Solar System, and,
in some ways, marks the transition from an object without and with interesting
geological and planetary processes occurring," he explains.
The tricky part is that
the classification for dwarf planets is fairly new, and can be a little
subjective. Brown has his own 'benchmarks' for
what makes something more dwarf planet-like than others, and it’ll be up to the
International Astronomical Union to decide if 2015 RR245 and 2014 UZ224 make
the official cut.
"It's also possible
some astronomers might argue that the object Gerdes found is too small to be
considered a dwarf planet, but for now, he says the term applies," NPRreports.
That said, anything to
make poor old Pluto a little less lonely out there is a win in our books.
