Published on 13 May 2019
Published on 13 May 2019
Researchers have discovered a dwarf planet far beyond the orbit of Pluto they believe strengthens the case for a large planet at the outer reaches of our solar system.
The newly found object is called 2015 TG387 or “The Goblin,” because of its letters and the fact it was first seen near Halloween.
It was discovered about 80 astronomical units (AU) from the sun — one AU is equivalent to the distance from the sun to Earth or about 150 million km. But that’s almost as close as it gets: its orbit can take the dwarf planet as far away as 2,300 AU, making it the most distant object known to science.
In a paper published in The Astronomical Journal on Tuesday, researchers suggest that its strange orbit, along with that of two other distant objects — Sedna and 2012 VP113 — supports the idea of a planet about seven times bigger than Earth that has yet to be detected at the outer edge of our solar system.
The existence of a Planet X — more recently referred to as Planet 9 — has been theorized since the early 1800s. First, it was used to explain the perturbations in Uranus’s orbit, which ended up being Neptune. Later, it was proposed to explain Neptune’s orbit. Though Pluto was discovered in 1930, it wasn’t large enough to account for any gravitational influences.
In the 1990s, more precise measurements of the outer planets were taken by the Voyager spacecraft and the existence of Planet X was put to rest.
But not quite.
Fast forward to 2003, when CalTech astronomer Mike Brown and colleagues discovered Sedna, a small object beyond Pluto (which eventually lead to the “demotion” of Pluto from planet to dwarf planet). Sedna is a planet smaller than Mercury.
Questions were raised about the nature of its orbit that didn’t seem to align with what astronomers observed with other planets
2015 TG387 was first discovered in October, 2015, using the Subaru Telescope in Hawaii. The closest it gets to Earth is about 65 AU. While 2012 VP113 and Sedna come closer, they don’t trek as far out.
The dwarf planet — only 300 kilometres in diameter — is believed to have an orbital period of 40,000 years. The orbit takes it beyond the Kuiper Belt, an area past Neptune where small icy worlds are found.
The fact that its orbit is so long means its discovery was somewhat fortuitous: with current instruments it would be detectable only one per cent of the time.
So why can astronomers find dwarf planets and not something that could be seven times larger than Earth?
“We think the big object is … between 500 to 1,000 astronomical units away. And we think it’s at its most distant point on its elongated orbit, so it’s very far away,” said Scott Sheppard, co-author of the paper in The Astronomical Journal and astronomer at the Carnegie Institution for Science.
“Whereas these smaller objects have elongated orbits as well, but we’re finding them at their closest approach to the sun, so they’d be brighter and be seen by reflected sunlight.”
The findings support a theory for a large planet whose orbit could be between 50,000 and 100,000 years.
“It’s basically exactly what we would predict,” said Brown, who was not involved in this paper. However, in 2016, he encouraged other astronomers to hunt for Planet 9.
“At this point, the Planet 9 hypothesis explains the alignment of these distant objects, these weird 90-degree twisted objects, a strange alignment of close objects,” Brown said. “I must say it all fits together really well.”
There are two leading theories for how this planet could have ended up out there: either it was captured by gravity as it passed our solar system or it formed in the inner solar system and was flung out when it came too close to Jupiter or Saturn. The latter theory draws more backing from astronomers.
“This is another piece of the puzzle,” said study co-author Chad Trujillo. “It’s not like we know exactly where this planet is. But the more objects we find that point to the planet, the more data we have, the more likely we are to find it.”
The jury’s still out on declaring with 100 per cent certainty that Planet 9 is lurking out there.
Brown, however, is confident that it exists and its discovery is on our doorstep.
“I am eternally optimistic,” Brown said. “I would not be surprised if we find it this year.”
Trujillo is a little more cautious, even when it comes to the chance it exists at all.
He believes that there’s a 25 per cent chance that a giant planet can explain it all. He uses the example of famed French astronomical mathematician Urbain LeVerrier who, after the discovery of Uranus in 1781, theorized a giant planet could explain Uranus’s perturbations. He was right (it was Neptune). But later, he theorized there was a planet within the orbit of Mercury (given the nickname Vulcan). He was wrong.
“He was right once and he was wrong once, and this was one of the greatest mathematicians of all time for astronomy, and he was only at 50 per cent,” Trujillo said. “If we can do 25 per cent, that’s good.”
Sheppard seems to be in the middle of these dwarf planet hunters.
“I would say we’re at the 80 to 90 per cent level; it’s not a guaranteed thing,” Sheppard said. “But there are a lot of things pointing to it existing out there.
“The hunt continues.”
A recent discovery has added evidence that Planet Nine – orbiting in the Oort Cloud far beyond Pluto – exists.
Astronomers looking for evidence of a large planet lurking at the fringes of our solar system have instead located an odd dwarf world that, while not precisely what they seek, nonetheless provides additional evidence of the mysterious Planet Nine.
Astronomical observers have identified a small celestial body technically within the Solar System that exhibits a strange orbit that — according to researchers — can only be explained by assuming that another much larger as-yet-undetected object is also describing a similar orbit around the sun.
For a handful of years astronomers have asserted the existence of a ninth planet well beyond the orbit of Pluto circling our sun and have been resolutely searching the heavens for proof.
The hunt became serious after skywatchers in 2016 noticed that several distant solar system objects were behaving strangely. The far-orbit solar system bodies — much farther away than Pluto — all orbited the sun at a pronounced angle from that of the inner planets.
The discovery suggested that the gravitational influence of another — and much larger — planet was affecting the orbits of the distant orbital bodies.
Now, recent findings noting the odd orbit of newly-discovered planetary object 2015 BP519 add evidence that Planet Nine is real.
2015 BP519, orbiting the sun at a 54 degree angle when compared to almost everything else inside the orbit of Pluto, has many astronomers theorizing that Planet Nine is the cause.
The discovery and confirmation of Planet Nine — and all far-orbit solar system bodies — is extremely problematic, given that it’s location is thought to be several times as distant as Pluto.
Even humanity’s most powerful telescopes have a very difficult time picking out a tiny dot that is also completely dark, as it is thought to be too distant to reflect the sun’s rays back to us.
Although it doesn’t help that astronomers are not sure exactly where to point their telescopes, the increasing body of evidence indicates that in the not-too-distant future, the mysterious Planet Nine is due for its closeup.
What do we call these volunteers? Fools or heroes?
No, it’s not Pluto. Unfortunately for die-hard astronomy fans, Pluto is still languishing in its dwarf planet classification, and now it may become replaced by an even more distant planet, hidden somewhere in the mysterious Kuiper Belt. The supposed planet, creatively nicknamed Planet Nine, has not been proven to exist yet, but astronomers have a wealth of data that points to something about 10 times the size of Earth lurking at the edge of the solar system.
The search for Planet Nine started relatively innocuously with some research in 2014: astronomers Scott Shephard and Chad Trujillo published a paper studying a strange object called Sedna, a 1,000-kilometer-wide trans-Neptunian object (TNO). TNOs are minor planets, asteroids, and other bodies who orbits taken them farther out than Neptune, and include Pluto and 10-30 other objects.
The strange thing about Sedna was that it’s incredibly long and eccentric orbit seemed to tie it to an unknown planet somewhere outside the solar system, leading Shephard and Trujillo to hypothesize there may be a ninth planet beyond Pluto.
This led a different pair of astronomers, Mike Brown and Konstantin Batygin, to start investigating other TNOs in hopes of finding a pattern that would show Planet Nine’s gravity in action.
In 2016, they announced that they had: several TNOs were shown to have orbits that were perpendicular to the normal orbital plane of the solar system, a phenomenon that can be explained by the existence of super-Earth-sized planet.
Based on the data collected, Brown and Batygin are 99.99% sure that Planet Nine exists.
Unfortunately, spotting Planet Nine has proved harder than they expected-even working with Shephard and Trujillo, Brown and Batygin have to rely primarily on one telescope, the Subaru Telescope in Hawaii.
Inclement weather and bad luck have repeatedly foiled their attempts at observing the planet directly. There’s always the chance that Planet Nine is ever farther out than expected, or that it’s much smaller than estimated, both of which would make it harder to see.
The other option? Planet Nine might not exist at all.
The idea of a giant free-floating planet (FFLOP) at the edge of our solar system was first proposed in 2014. Two years later, a team from Sweden’s Lund University proposed that Planet 9 was an exoplanet, drawn in from outside our own solar system.
This theory has now been debunked by Dr. Richard Parker from the Department of Physics and Astronomy at the University of Sheffield along with several colleagues from ETH Zurich.
Parker’s team simulated the so-called ‘stellar nursery’ stage of our sun’s early life (roughly 4.5 billion years ago). They found that even in the most favorable conditions for the interstellar pickpocketing scenario, there was only between a one and six percent chance planets would be captured and follow an orbit similar to Planet 9.
As the team applied a few additional constraints to their simulation, the probability of interstellar planetary capture dropped to zero.
“Planet 9 could have formed close to the sun like the other planets. Then, however, while the solar system was young and dynamically active, gravitational interactions could have scattered Planet 9 to the outer regions of the solar system on a stable orbit,” Dimitri Veras, an astrophysicist working at Britain’s University of Warwick, told Newsweek.
Astronomers have spent centuries searching for a large planetary body at the edge of our solar system that would explain the unusual behavior of icy objects in the Kuiper belt that encircles our solar system without success.
Planet 9’s existence has yet to be definitively confirmed, however, as scientists have yet to detect, let alone directly observe, the celestial body.
Astronomers and astrophysicists are still in the process of scouring the Kuiper Belt for more objects that could point the way to the mysterious giant planet; a tall order given that such a massive object would take between 10,000 and 20,000 years to orbit the sun.
Planet 9 is believed to be at least 10 times the size of Earth, which makes it unlikely that it could have formed so far out from the sun, initially fueling speculation that it could have been taken from another planetary system.
Like Captain Kirk would say, weird or what? I say it’s alien juvenile delinquents.