Planet 9 Archives

February 20, 2023February 20, 2023 by Nancy Atkinson

If Planet 9 has Moons, Would That Help Us Find It?

Artist's concept of the hypothetical "Planet Nine." Could it have moons? Credit: NASA/JPL-Caltech/Robert Hurt

Planet 9 continues to remain elusive. This potential super-Earth-sized object in the outer Solar System is only hypothetical, as something out there appears to be gravitationally influencing several Kuiper Belt Objects into unusual orbits. Whatever or wherever it may be, Planet 9 has yet to be found, despite several different hypotheses and numerous observational searches.

But what if Planet 9 has moons? Could they help us find it? A new paper speculates that any moons orbiting the theoretical planet could provide indirect clues to the location of Planet 9, while revealing some basic properties of this mysterious object.

September 13, 2022September 15, 2022 by Laurence Tognetti

Flying to (Hypothetical) Planet 9: Why visit it, how could we get there, and would it surprise us like Pluto?

In a recent study submitted to Earth and Planetary Astrophysics, an international team of researchers discuss the various mission design options for reaching a hypothetical Planet 9, also known as “Planet X”, which state-of-the-art models currently estimate to possess a semi-major axis of approximately 400 astronomical units (AU). The researchers postulate that sending a spacecraft to Planet 9 could pose scientific benefits much like when NASA’s New Horizons spacecraft visited Pluto in 2015. But does Planet 9 actually exist?

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August 28, 2021August 28, 2021 by Brian Koberlein

If Planet 9 is out There, Here's Where to Look

Illustration of the hypothetical Planet 9. Credit: R. Hurt/IPAC, Caltech

There are eight known planets in the solar system (ever since Pluto was booted from the club), but for a while, there has been some evidence that there might be one more. A hypothetical Planet 9 lurking on the outer edge of our solar system. So far this world has eluded discovery, but a new study has pinned down where it should be.

December 17, 2020December 17, 2020 by Evan Gough

Astronomers Have Found Planet 9… in Another Solar System

This 11-Jupiter-mass exoplanet called HD106906 b occupies an unlikely orbit around a double star 336 light-years away and it may be offering clues to something that might be much closer to home: a hypothesized distant member of our Solar System dubbed “Planet Nine.” This is the first time that astronomers have been able to measure the motion of a massive Jupiter-like planet that is orbiting very far away from its host stars and visible debris disc. Image Credit: ESA/Hubble, M. Kornmesser

Even with all we’ve learned about our own Solar System, especially in the last couple of decades, researchers still face many unanswered questions. One of those questions regards the so-called Planet Nine. The Planet Nine hypothesis states that there’s a massive planet in our Solar System orbiting at a great distance from the Sun.

Nobody’s ever observed the hypothesized planet; the evidence for it lies in a cluster of bodies that orbit the Sun 250 times further out than Earth does. These objects are called e-TNOs, for extreme Trans-Neptunian Objects. According to the hypothesis, Planet Nine’s gravity is responsible for the unusual clustered orbits of these e-TNOs.

Now astronomers have found a distant solar system with its own Planet Nine, and that discovery is breathing new life into the hypothesis.

August 19, 2020August 19, 2020 by Matt Williams

The Sun Might Have Once Had a Binary Companion Star

For some time now, astronomers have known that the majority of systems in our galaxy consist of binary pairs rather than individual stars. What’s more, in recent decades, research has revealed that stars like our Sun are actually born in clusters within solar nebulas. This has led to efforts in recent years to locate G-type (yellow dwarf) stars in our galaxy that could be the Sun’s long-lost “solar siblings.”

And now, a new study by Harvard astronomers Amir Siraj and Prof. Abraham Loeb has shown that the Sun may once have once had a very similar binary companion that got kicked out of our Solar System. If confirmed, the implications of this could be groundbreaking, especially where theories on how the Oort Cloud formed and whether or not our system captured a massive object (Planet Nine) in the past.

May 29, 2020May 29, 2020 by Evan Gough

Maybe the Elusive Planet 9 Doesn’t Exist After All

The imagined view from Planet Nine looking back toward the sun. Astronomers think the huge, distant planet is gaseous, similar to the other giant planets in our solar system.

Oh Planet Nine, when will you stop toying with us?

Whether you call it Planet Nine, Planet X, the Perturber, Jehoshaphat, “Phattie,” or any of the other proposed names—either serious or flippant—this scientific back and forth over its existence is getting exhausting.

Is this what it was like when they were arguing whether Earth is flat or round?

March 1, 2019March 1, 2019 by Evan Gough

More Evidence that Planet 9 is Really Out There

Artist's impression of Planet Nine as an ice giant eclipsing the central Milky Way, with a star-like Sun in the distance. Neptune's orbit is shown as a small ellipse around the Sun. The sky view and appearance are based on the conjectures of its co-proposer, Mike Brown. Image Credit: By nagualdesign; Tom Ruen, background taken from File:ESO - Milky Way.jpg - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=47069857

What’s going on in the distant reaches of our Solar System? Is there a Planet 9 out there?

Out in the frigid expanse of our System, there are bodies on orbital paths that don’t make sense in terms of our eight-planet Solar System. There seems to be an undiscovered body out there, several times more massive than Earth, shaping the orbits of some Kuiper Belt Objects (KBOs), and driving astronomers to look deeper and more thoroughly into the extreme reaches of our System.

What they’re looking for is the mysterious, and so far unproven, ninth planet.

February 27, 2019February 27, 2019 by Evan Gough

The Record for the Most Distant Object in the Solar System has been Shattered. Introducing FarFarOut at 140 Astronomical Units

Artist concept of 2018 VG18 "Farout". Credit Roberto Molar Candanosa/Carnegie Institution for Science.

Remember Far Out, the distant planet at the far reaches of the Solar System, that was discovered in December, 2018? Well, it has been kicked unceremoniously off its pedestal as the most distant object after a short, two-month reign. In its place is the very newly-discovered FarFarOut (FFO.)

And if it weren’t for a heavy snowfall, things might have turned out differently.

January 23, 2019January 23, 2019 by Evan Gough

A Disc of Icy Material, not Planet 9, Might Explain the Strange Movements in the Outer Solar System

Could a disk of icy material be responsible for the strange orbits of distand objects in our Solar System? Image Credit: ESO/M. Kornmesser

Is there or isn’t there a Planet 9? Is there a planet way out on the outskirts of our Solar System, with sufficient mass to explain the movements of distant objects? Or is a disc of icy material responsible? There’s no direct evidence yet of an actual Planet 9, but something with sufficient mass is affecting the orbits of distant Solar System objects.

A new study suggests that a disc of icy material causes the strange movements of outer Solar System objects, and that we don’t need to invent another planet to explain those movements. The study comes from
Professor Jihad Touma, from the American University of Beirut, and
Antranik Sefilian, a PhD student in Cambridge’s Department of Applied Mathematics and Theoretical Physics. Their results are published in the Astronomical Journal.

December 17, 2018 by Evan Gough

Just discovered! “Farout”, the Farthest Object Ever Seen in the Solar System

Astronomers have discovered a distant body that’s more than 100 times farther from the Sun than Earth is. Its provisional designation is 2018 VG18, but they’ve nicknamed the planet “Farout.” Farout is the most distant body ever observed in our Solar System, at 120 astronomical units (AU) away.

The International Astronomical Union’s Minor Planet Center announced Farout’s discovery on Monday, December 17th, 2018. This newly-discovered object is the result of a team of astronomers’ search for the elusive “Planet X” or “Planet 9,” a ninth major planet thought to exist at the furthest reaches of our Solar System, where its mass would shape the orbit of distant planets like Farout. The team hasn’t determined 2018 VG18’s orbit, so they don’t know if its orbit shows signs of influence from Planet X.

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