Overview
Caltech researchers have found mathematical
evidence suggesting there may be a "Planet
X" deep in the solar system. This hypothetical
Neptune-sized planet orbits our Sun in a highly
elongated orbit far beyond Pluto. The object,
which the researchers have nicknamed "Planet
Nine," could have a mass about 10 times
that of Earth and orbit about 20 times farther
from the Sun on average than Neptune. It may
take between 10,000 and 20,000 Earth years to
make one full orbit around the Sun.
The
announcement does not mean there is a new planet
in our solar system. The existence of this distant
world is only theoretical at this point and
no direct observation of the object nicknamed
"Planet 9" have been made. The mathematical
prediction of a planet could explain the unique
orbits of some smaller objects in the Kuiper
Belt, a distant region of icy debris that extends
far beyond the orbit of Neptune. Astronomers
are now searching for the predicted planet.
In
Depth
In January 2015, Caltech astronomers Konstantin
Batygin and Mike Brown announced new research
that provides evidence of a giant planet tracing
an unusual, elongated orbit in the outer solar
system. The prediction is based on detailed
mathematical modeling and computer simulations,
not direct observation.
This
large object could explain the unique orbits
of at least five smaller objects discovered
in the distant Kuiper Belt.
"The
possibility of a new planet is certainly an
exciting one for me as a planetary scientist
and for all of us," said Jim Green, director
of NASA's Planetary Science Division. "This
is not, however, the detection or discovery
of a new planet. It's too early to say with
certainty there's a so-called Planet X. What
we're seeing is an early prediction based on
modeling from limited observations. It's the
start of a process that could lead to an exciting
result."
The
Caltech scientists believe Planet X may have
has a mass about 10 times that of Earth and
be similar in size to Uranus or Neptune. The
predicted orbit is about 20 times farther from
our Sun on average than Neptune (which orbits
the Sun at an average distance of 2.8 billion
miles). It would take this new planet between
10,000 and 20,000 years to make just one full
orbit around the Sun (where Neptune completes
an orbit roughly every 165 years).
When
was it Discovered?
Planet X has not yet been discovered, and there
is debate in the scientific community about
whether it exists. The prediction in the Jan.
20 issue of the Astronomical Journal is based
on mathematical modeling.
What
is its Name?
Batygin and Brown nicknamed their predicted
object "Planet Nine," but the actual
naming rights of an object go to the person
who actually discovers it. The name used during
previous hunts for the long suspected giant,
undiscovered object beyond Neptune is "Planet
X."
If
the predicted world is found, the name must
be approved by the International Astronomical
Union. Planets are traditionally named for mythological
Roman gods.
Why
Do They Think It's There?
Astronomers studying the Kuiper Belt have noticed
some of the dwarf planets and other small, icy
objects tend to follow orbits that cluster together.
By analyzing these orbits, the Caltech team
predicted the possibility that a large, previously
undiscovered planet may be hiding far beyond
Pluto.
Source
They
estimate the gravity of this potential planet
might explain the unusual orbits of those Kuiper
objects.
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