Page 40 - All About Space 68 - 2017 UK

Search for Planet Nine

Cassini's orbit has had fluctuations planets. “As we point out in our most recent paper,
which could be caused by a large the data, biased or not, still suggests that there is at
planet beyond Pluto least one massive perturber beyond Pluto,” he says,
“and probably more than one”.
Last year, Marcos and his colleagues revisited the
six objects behind the original Planet Nine paper, and
found they are not as stable as it was first thought.
The evidence led them to believe the most stable
scenario is one involving not just one new planet, but
two, or potentially more, lurking beyond Pluto. The
newest models suggest there is one potential planet
at a distance of 60 astronomical units (AU), from the
Sun – 60 times the distance between Earth and the
Sun. On top of this, they think there is another much
larger planet, between 300 and 400 AU away – which
resembles the Planet Nine we are familiar with. The
© NASA/JPL-Caltech mass of Earth. This is tiny compared to the Planet
first object, they say, would only be a tenth of the
Nine predicted by Batygin and Brown, which is ten
times Earth’s mass.
Kat Volk and Renu Malhotra of the University of
Planet Nine's gravity would explain section of the sky. “Given the ‘pencil-beam’ nature Arizona's Lunar and Planetary Laboratory say beyond
the clustering of distant objects of the OSSOS survey, it has a negligible chance of 50 AU, the inclination of objects in the Kuiper
finding Planet Nine by design,” says Batygin. One Belt differed from predictions by eight degrees, on
argument against Planet Nine is that there are biases average. They suggest this warping could be caused
in the data used by Brown and Batygin, according by a planet around the size of Mars, in addition to
to the team behind the OSSOS paper. “They have the Planet Nine predicted by Batygin and Brown.
been arguing for quite some time that the data is "The most likely explanation for our results is that
affected by strong detection biases, and therefore, is there is some unseen mass," says Volk, a postdoctoral
not suitable to arrive to any conclusions regarding the fellow at LPL and the lead author of the study.
presence of planets beyond Pluto,” says Marcos. "According to our calculations, something as massive
as Mars would be needed to cause the warp that
Marcos and his colleagues have been looking into
© Heather Roper/LPL the mystery themselves, and they have come up with we measured." The pair say our chance to catch a
an even more intriguing suggestion. They believe
glimpse of the mysterious object might come fairly
soon, once construction of the Large Synoptic Survey
there could be biases, but that these would not be
Telescope is completed in 2020.
enough to rule out perturbations caused by other

Could Planet Nine exist?

Tilt of the Sun Cassini’s orbit Minor planets The sky is a Super-Earths
The six-degree Tiny fluctuations The clustering huge place Planet Nine might
tilt of the Sun has in Cassini’s orbit of objects in Surveys that have be something
been a mystery around Saturn the Kuiper Belt not found Planet between a rocky
for 150 years, make more sense is not properly Nine may have planet and a gas
discovery of with the understood, been restricted by giant, which
Planet Nine could existence of Planet Nine could where they have is common FOR
help explain this Planet Nine clarify our beliefs been searching in exoplanets

Other objects Biases in Very low We haven’t NASA is not
out there telescope data significance spotted it yet convinced
If Planet Nine is real, We’re only finding The number of Some say if Planet NASA's Planetary AGAINST
it should produce objects that come objects found Nine was as large Science Division
many more distant very close to the with these odd as expected, we says it's too
objects with a Sun, compared to orbits statistically could easily see it early to say with
strange, unexpected how distant they has a very low using equipment certainty there is
alignment get from it significance on Earth an extra planet

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