The six most distant known objects in the solar system with orbits exclusively beyond Neptune (magenta) all mysteriously line up in a single direction. Also, when viewed in three dimensions, they tilt nearly identically away from the plane of the solar system. Batygin and Brown show that a planet with 10 times the mass of the earth in a distant eccentric orbit anti-aligned with the other six objects (orange) is required to maintain this configuration. Credit: Caltech/R. Hurt (IPAC); [Diagram created using WorldWide Telescope.]
Last year, Caltech astronomers Mike Brown and Konstantin Batygin found indirect evidence for the existence of a large planet in the outer reaches of our Solar System — likely located out past Pluto — and since then, the search has been on. The latest research continues to show signs of an unseen planet, the hypothetical Planet 9.
Astronomers using the Gran Telescopio CANARIAS (GTC) in the Canary Islands looked at two distant asteroids called Extreme Trans Neptunian Objects’ (ETNOs), and spectroscopic observations show and their present-day orbits could be the result of a past interaction with a large “superearth”-type object orbiting the Sun at a distance between 300 to 600 AU.
Researchers say the orbits of asteroids 2004 VN112 and 2013 RF98 suggest that the two were once a binary asteroid which separated after an encounter a large body, with a mass of between 10 and 20 Earth masses.
“The similar spectral gradients observed for the pair 2004 VN112 – 2013 RF98 suggests a common physical origin,” said Julia de León, the first author of a new paper, and who is an astrophysicist at the Instituto de Astrofísica de Canarias (IAC). “We are proposing the possibility that they were previously a binary asteroid which became unbound during an encounter with a more massive object.”
Sequence of images taken with the Gran Telescopio CANARIAS (GTC) to identify one of the ETNO´s studied in this article, 2013 RF98, where one can see how it moves during four consecutive nights. Below, right, visible spectra obtained with the GTC of the two objects 2004 VN112 and 2013 RF98. The red lines show the gradients of the spectra. Credit: Julia de León (IAC).
To test their hypothesis, the team performed thousands of simulations to see how the poles of the orbits would separate as time went on. The results of these simulations suggest that a possible Planet 9 could have separated the pair of asteroids around 5 to 10 million years ago.
de León said this could explain, in principle, how these two asteroids, starting as a pair orbiting one another, became gradually separated in their orbits after an encounter with a much more massive object at a particular moment in time.
The tale of Planet 9 started in 2014, when astronomers Chad Trujillo and Scott Shepard were studying the motions of large objects in the Kuiper Belt and realized that a large planet in the outer Solar System must be altering orbits of several ETNOs the in Kuiper Belt.
Brown and Batygin were looking to verify or refute the research of Trujillo and Shepard, and they painstakingly analyzed the movement of various KBOs. They found that six different objects all seem to follow a very similar elliptical orbit that points back to the same region in space.
All the bodies were found to be inclined at a plane of about 30-degrees different from almost everything else in the Solar System. Brown said the odds of these orbits all occurring randomly are about 1 in 100.
But calculations revealed the orbits could be influenced by a massive planet way out beyond the orbit of Pluto, about 200 times further than the distance from the Sun to the Earth. This planet would be Neptune-sized, roughly 10 times more massive than Earth.
It hasn’t been found yet, but the hunt is on by large telescopes around the world, and a new citizen science project allows people around the world to join in the search.
The latest findings of by de León and team could help point the way to where Planet 9 might be lurking.
Welcome, come in to the 497th Carnival of Space! The Carnival is a community of space science and astronomy writers and bloggers, who submit their best work each week for your benefit. I’m Susie Murph, part of the team at Universe Today and CosmoQuest. So now, on to this week’s stories! Continue reading “Carnival of Space #497”
Artist concept of Planet 9. Credit: NASA/JPL-Caltech.
Citizen science projects are a great way for anyone to be involved in the scientific process. Average, everyday folks have discovered things like supernovae, previously unseen craters on the Moon and Mars and even new planets orbiting a distant star.
Now, you could be part of one of the most exciting quests yet: finding a mysterious, unseen planet in the far reaches of our own solar system. Last year, Caltech astronomers Mike Brown and Konstantin Batygin found indirect evidence for the existence of a large planet, likely located out past Pluto, and since then, the search has been on. But so far, it has come up empty. And so, astronomers decided they would bring in a little help: You.
“Backyard Worlds: Planet 9 has the potential to unlock once-in-a-century discoveries, and it’s exciting to think they could be spotted first by a citizen scientist,” said UC Berkeley postdoctoral researcher Aaron Meisner, who is helping to head up this latest citizen science project.
A previously cataloged brown dwarf named WISE 0855?0714 shows up as a moving orange dot (upper left) in this loop of WISE images spanning five years. By viewing movies like this, anyone can help discover more brown dwarfs or even a 9th planet. Credit: NASA/WISE.
People who sign on to the Backyard World: Planet 9 website will be basically using the same type of technique that was used to find the last planet discovered in our solar system, Pluto. Clyde Tombaugh used a special machine that systematically switched images on glass astronomical plates back and forth, looking for any objects in the night sky that ‘moved’ between the images.
For Backyard Worlds: Planet 9, users will view brief “flipbook” movies made from images captured by NASA’s Wide-field Infrared Survey Explorer (WISE) mission. A faint spot seen moving through background stars might be a new and distant planet in our solar system. Or it could be a nearby brown dwarf star, which would be another exciting discovery.
WISE’s infrared images cover the entire sky about six times over. This has allowed astronomers to search the images for faint, glowing objects that change position over time, which means they are relatively close to Earth. Objects that produce their own faint infrared glow would have to be large, Neptune-size planets or brown dwarfs, which are slightly smaller than stars. WISE images have already turned up hundreds of previously unknown brown dwarfs, including the objects fairly close to us, so astronomers hope that the Backyard Worlds search will turn up a new nearest neighbor to our sun.
NASA wants to bring in all the humans it can for this search, because the human eye is much better than computers at seeing changes between images.
“Automated searches don’t work well in some regions of the sky, like the plane of the Milky Way galaxy, because there are too many stars, which confuses the search algorithm,” said Meisner.
“There are just over four light-years between Neptune, the farthest known planet in our solar system, and Proxima Centauri, the nearest star, and much of this vast territory is unexplored,” said NASA astronomer Marc Kuchner, the lead researcher and an astrophysicist at NASA’s Goddard Space Flight Center. “Because there’s so little sunlight, even large objects in that region barely shine in visible light. But by looking in the infrared, WISE may have imaged objects we otherwise would have missed.”
Artist's concept of the hypothetical "Planet Nine." Could it have moons? Credit: NASA/JPL-Caltech/Robert Hurt
Ever since its existence was first proposed, the evidence for Planet 9 continues to mount. But of course, said evidence has been entirely indirect, consisting mostly of studies that show how the orbits of Trans-Neptunian Objects (TNOs) are consistent with a large object crossing their path. However, evidence is also emerging that comes from the center of the Solar System itself.
This latest line of evidence comes from Caltech, where researchers Elizabeth Bailey, Konstantin Batygin, and Michael E. Brown (the latter of whom were the ones who first proposed Planet 9’s existence) have published a new study linking solar obliquity to the existence of Planet 9. Essentially, they claim that the axial tilt of the Sun (6°) could be due to the gravitational influence a large planet with an extreme orbit.
To recap, the issue of Planet was first raised in 2014 by astronomers Scott Sheppard and Chadwick Trujillo. Noting the similarities in the orbits of distant Trans-Neptunian Objects (TNOs), they postulated that a massive object was likely influencing them. This was followed in 2016 by Konstantin Batygin and Michael E. Brown of Caltech suggesting that an undiscovered planet was the culprit.
The orbits of several KBOs provide indications about the possible existence of Planet 9. Credit: Caltech/R. Hurt (IPAC)
Calling this body Planet 9, they speculated that it had a mass 10 times greater than that of Earth, and took 20,000 years to complete a single orbit of our Sun. They also speculated that its orbit was tilted relative to the other planets of our Solar System, and extremely eccentric. And little by little, examinations of other Solar bodies have shown that Planet 9 is likely out there.
For the sake of their study – “Solar Obliquity Induced by Planet Nine“, which was recently published in the Astrophysical Journal – the research team (led by Bailey) looked to the obliquity of the Sun. As they state in their paper, the six-degree axial tilt of the Sun can only be explained in one of two ways – either as a result of an asymmetry that was present during the formation of Solar System, or because of an external source of gravity.
To test this hypothesis, Bailey, Batygin and Brown used an analytic model to test how interactions between Planet 9 and the rest of the Solar System would effect their orbits over the course of the last 4.5 billion years. As Elizabeth Bailey, a graduate student at Caltech’s Division of Geological and Planetary Sciences and the lead author on the paper, told Universe Today via email:
“We simulated the solar system’s motion. Planet 9 forces the solar system to slowly wobble. If Planet 9 is out there, we are in the process of wobbling right now, as we speak! But it happens very slowly, a few degrees tilt per billion years. Meanwhile the sun is not wobbling much, so it looks like the sun is tilted. A range of Planet 9 parameters cause exactly the configuration of the sun that we see today.
Animated diagram showing the spacing of the Solar Systems planet’s, the unusually closely spaced orbits of six of the most distant KBOs, and the possible “Planet 9”. Credit: Caltech/nagualdesign
In the end, they concluded that the Sun’s obliquity could only be explained by the influence of giant planet with an extreme orbit, one that is consistent with the characteristics attributed to Planet 9. In other words, the existence of Planet 9 offers an explanation for the Sun’s peculiar behavior, something which has remained a mystery until now.
“Planet Nine was first hypothesized because the orbits of objects in the outer reaches of the solar system are confined in physical space,” said Bailey. “Those orbits would be all over the place unless something is currently stopping them. The only explanation so far is Planet Nine. For over 150 years, people have wondered why the sun is tilted. Personally I’d say that Planet 9 offers the first satisfying explanation. If it exists, it tilted the sun.”
The Arizona research team was led by Renu Malhotra, a Regents’ Professor of Planetary Sciences in the University of Arizona’s Lunar and Planetary Lab. For the sake of their study, titled “Corralling a Distant Planet with Extreme Resonant Kuiper Belt Objects“, they examined the orbital patterns of four extreme Kuiper Belt Objects (KBOs), which have the longest orbital periods of any known objects.
Artist’s impression of the the possible Planet 9 at the edge of the Solar System. Credit: Robin Dienel/Carnegie Science
According to their calculations, the presence of a massive planet – one that would complete an orbit around the Sun every 17,117 years, and at an average distance (semimajor axis) of 665 AU – would explain the orbital pattern of these four objects. These results were consistent with the estimates concerning the orbital period of Planet 9, its orbital path, and it mass.
“We analyzed the data of these most distant Kuiper Belt objects,” Malhotra said, “and noticed something peculiar, suggesting they were in some kind of resonances with an unseen planet… Our paper provides more specific estimates for the mass and orbit that this planet would have, and, more importantly, constraints on its current position within its orbit.”
Looks like Planet 9’s days of hiding in the outer Solar System may be numbered!
Special Guest:
This week’s special guest is Dr. Voula Saridakis, a professor at Lake Forest College in Illinois specializing in the history of science and astronomy, who runsthe History of Astronomy on Twitter at @histastro
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Based on data obtained by the Dark Energy Survey (DES), a team of scientists have obtained evidence of another TNO beyond Pluto. Credit: ESO/L. Calçada/Nick Risinger
The Kuiper Belt has been an endless source of discoveries over the course of the past decade. Starting with the dwarf planet Eris, which was first observed by a Palomar Observatory survey led by Mike Brown in 2003, many interesting Kuiper Belt Objects (KBOs) have been discovered, some of which are comparable in size to Pluto.
And according to a new report from the IAU Minor Planet Center, yet another body has been discovered beyond the orbit of Pluto. Officially designated as 2014 UZ224, this body is located about 14 billion km (90 AUs, or 8.5 billion miles) from the Sun. This dwarf planet is not only the latest member of the our Solar family, it is also the second-farthest body from our Sun with a stable orbit.
The discovery was made by David Gerdes, a professor of astrophysics at the University of Michigan, and various colleagues associated with at the Dark Energy Survey (DES) – a project which relies on the Cerro Tololo Inter-American Observatory in Chile. In the past, Gerdes’ research has focused on the detection of dark energy and the expansion of the Universe.
The DECam instrument, shown before it was inserted into the Blanco telescope at the Cerro Tololo Observatory. Credit: noao.edu
Towards this end, DES has spent the past five years surveying roughly one-eighth of the sky using the Dark Energy Camera (DECam), a 570-Megapixel camera mounted on the Victor M. Blanco telescope at Cerro Tololo. This instrument was commissioned by the US. Dept of Energy to conduct surveys of distant galaxies, and Dr. Gerdes had a hand in creating.
Not surprisingly, this same technology has also allowed for discoveries to be made at the edge of the Solar System. Two years ago, this is precisely what Gerdes challenged a group of undergraduate students to do (as part of a summer project). These students examined images taken by DES between 2013-2016 for indications of moving objects. Since that time, the analysis team has grown to include senior scientists, postdocs, graduate and undergraduate students.
Whereas distant stars and galaxies would appear stationary in these images, distant TNOs showed up in different places over time – hence why are called “transients”. As Dr. Gerdes explains in his 2014 UZ224 Fact Sheet, which is available through his University of Michigan homepage:
“To identify transients, we used a technique known as “difference imaging”. When we take a new image, we subtract from it an image of the same area of the sky taken on a different night. Objects that don’t change disappear in this subtraction, and we’re left with only the transients… This process yields millions of transients, but only about 0.1% of them turn out to be distant minor planets. To find them, we must “connect the dots” and determine which transients are actually the same thing in different positions on different nights. There are many dots and MANY more possible ways to connect them.”
Images of 2014 UZ224, shown on three slides obtained by the DECam. Credit: David Gerdes/DES/University of Michigan
This was a difficult process. In addition to needing thousands of computers at Fermilab to process the hundreds of terabytes of data, the team had to write special programs to do it. Gerdes and his colleagues also relied on help from Professors Masao Sako and Gary Bernstein of the University of Pennsylvania, who contributed the key breakthroughs that allowed them to perform difference imaging over the entire survey area.
In the end, dozens of new Trans-Neptunian Objects (TNOs) were discovered, one of which was 2014 UZ224. According to their observations, its diameter could be anywhere from 350 to 1200 km, and it takes 1,136 years to complete a single orbit of our Sun. For the sake of perspective, Pluto is 2370 km in diameter, and has an orbital period of 248 years.
Stephanie Hamilton, a graduate student at the University of Michigan, was personally involved with the project. Her role was to determine the size of 2014 UZ224, which was difficult from initial observations alone. As she told Universe Today via email:
“The object’s brightness in visible light alone depends both on its size and how reflective it is, so you can’t uniquely determine one of those properties without assuming a value for the other. Fortunately there’s a solution to that problem – the heat the object emits is also proportional to its size, so obtaining a thermal measurement in addition to the optical measurements means we would then be able to calculate the object’s size and albedo (reflectance) without having to assume one or the other.
“We were able to obtain an image of our object at a thermal wavelength using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. I am working on combining all of our data together to determine the size and albedo, and we expect to submit a paper on our results around mid-November or so.”
Artistic rendering shows the distant view from theoretical Planet Nine back towards the sun. The planet is thought to be gaseous, similar to Uranus and Neptune. Hypothetical lightning lights up the night side. Credit: Caltech/R. Hurt (IPAC)
But as with all things related to “dwarf planets”, there has been some disagreement over this discovery. Given the dimensions of the object, there are some who question whether or not the label applies. But as Gerdes indicates on the Fact Sheet, this body fits most of the prerequisites:
“According to the official IAU guidelines, a dwarf planet must satisfy four criteria. It must a) orbit the sun (check!), b) not be a satellite (check!) c) not have cleared the neighborhood around its orbit (check!) and d) have enough mass to be round. It’s this last item that’s uncertain, and the only way for sure is to get a picture that’s detailed enough to actually see its shape. Nevertheless, an object over 400 km in diameter is likely to be round.”
Gerdes and his team expect to be busy, authoring the paper that will detail their findings, using the ALMA array to get more assessments of 2014 UZ224 size, and sifting through the data to look for more objects in the Kuiper Belt. This includes the fabled Planet 9, which astronomers have been seeking out for years.
Given its distance from the Sun, 2014 UZ224’s orbit would not be influenced by the presence of Planet 9, and is therefore of no help. However, Gerdes is optimistic that the evidence of this massive body is there in the data. Given time, and a lot of data-processing, they just might find it! In the meantime, this newly discovered object is likely to be the focal point of a lot of fascinating research.
“It’s an interesting object in its own right – distant objects like this are ‘cosmic leftovers’ from the primordial disk that gave birth to the solar system,” writes Gerdes. “By studying them and learning more about their distribution, orbital characteristics, sizes, and surface properties, we can learn more about the processes that gave birth to the solar system and ultimately to us.”
Artist's impression of the the possible Planet 9 at the edge of the Solar System. Credit: Robin Dienel/Carnegie Science
In 2014, Scott Sheppard of the Carnegie Institution for Science and Chadwick Trujillo of Northern Arizona University proposed an interesting idea. Noting the similarities in the orbits of distant Trans-Neptunian Objects (TNOs), they postulated that a massive object was likely influencing them. This was followed in 2016 by Konstantin Batygin and Michael E. Brown of Caltech suggesting that an undiscovered planet was the culprit.
Since that time, the hunt has been on for the infamous “Planet 9” in our Solar System. And while no direct evidence has been produced, astronomers believe they are getting closer to discerning its location. In a paper that was recently accepted by The Astronomical Journal, Sheppard and Trujillo present their latest discoveries, which they claim are further constraining the location of Planet 9.
For the sake of their study, Sheppard and Trujillo relied on information obtained by the Dark Energy Camera on the Victor Blanco 4-meter telescope in Chile and the Japanese Hyper Suprime-Camera on the 8-meter Subaru Telescope in Hawaii. With the help of David Tholen from the University of Hawaii, they have been conducting the largest deep-sky survey for objects beyond Neptune and the Kuiper Belt.
An illustration of the orbits of the new and previously known extremely distant Solar System objects – showing the clustering in orbits that indicates that possible presence of Planet X. Credit: Robin Dienel/Carnegie Science
This survey is intended to find more objects that show the same clustering in their orbits, thus offering greater evidence that a massive planet exists in the outer Solar System. As Sheppard explained in a recent Carnegie press release:
“Objects found far beyond Neptune hold the key to unlocking our Solar System’s origins and evolution. Though we believe there are thousands of these small objects, we haven’t found very many of them yet, because they are so far away. The smaller objects can lead us to the much bigger planet we think exists out there. The more we discover, the better we will be able to understand what is going on in the outer Solar System.”
Their most recent discovery was a small collection of more extreme objects who’s peculiar orbits differ from the extreme and inner Oort cloud objects, in terms of both their eccentricities and semi-major axes. As with discoveries made using other instruments, these appear to indicate the presence of something massive effecting their orbits.
All of these objects have been submitted to the International Astronomical Union’s (IAU) Minor Planet Center for designation. They include 2014 SR349, an extreme TNO that has similar orbital characteristics as the previously-discovered extreme bodies that led Sheppard and Trujillo to infer the existence of a massive object in the region.
Another is 2014 FE72, an object who’s orbit is so extreme that it reaches about 3000 AUs from the Sun in a massively-elongated ellipse – something which can only be explained by the influence of a strong gravitational force beyond our Solar System. And in addition to being the first object observed at such a large distance, it is also the first distant Oort Cloud object found to orbit entirely beyond Neptune.
Artist’s impression of Planet Nine as an ice giant eclipsing the central Milky Way, with a star-like Sun in the distance. Credit: ESO/Tomruen/nagualdesign
And then there’s 2013 FT28, which is similar but also different from the other extreme objects. For instance, 2013 FT28 shows similar clustering in terms of its semi-major axis, eccentricity, inclination, and argument of perihelion angle, but is different when it comes to its longitude of perihelion. This would seem to indicates that this particular clustering trend is less strong among the extreme TNOs.
Beyond the work of Sheppard and Trujillo, nearly 10 percent of the sky has now been explored by astronomers. Relying on the most advanced telescopes, they have revealed that there are several never-before-seen objects that orbit the Sun at extreme distances.
And as more distant objects with unexplained orbital parameters emerge, their interactions seem to fit with the idea of a massive distant planet that could pay a key role in the mechanics of the outer Solar System. However, as Sheppard has indicated, there really isn’t enough evidence yet to draw any conclusions.
“Right now we are dealing with very low-number statistics, so we don’t really understand what is happening in the outer Solar System,” he said. “Greater numbers of extreme trans-Neptunian objects must be found to fully determine the structure of our outer Solar System.”
Alas, we don’t yet know if Planet 9 is out there, and it will probably be many more years before confirmation can be made. But by looking to the visible objects that present a possible sign of its path, we are slowly getting closer to it. With all the news in exoplanet hunting of late, it is interesting to see that we can still go hunting in our own backyard!
Based on data obtained by the Dark Energy Survey (DES), a team of scientists have obtained evidence of another TNO beyond Pluto. Credit: ESO/L. Calçada/Nick Risinger
Beyond the orbit of Neptune, the farthest recognized-planet from our Sun, lies the mysteries population known as the Trans-Neptunian Object (TNOs). For years, astronomers have been discovering bodies and minor planets in this region which are influenced by Neptune’s gravity, and orbit our Sun at an average distance of 30 Astronomical Units.
In recent years, several new TNOs have been discovered that have caused us to rethink what constitutes a planet, not to mention the history of the Solar System. The most recent of these mystery objects is called “Niku”, a small chunk of ice that takes its name for the Chinese word for “rebellious”. And while many such objects exist beyond the orbit of Neptune, it is this body’s orbital properties that really make it live up to the name!
In a paper recently submitted to arXiv, the international team of astronomers that made the discovery explain how they found the TNO using the Panoramic Survey Telescope and Rapid Response System 1 Survey (Pan-STARRS 1). Measuring just 200 km (124 miles) in diameter, this object’s orbit is tilted 110° to the plane of the Solar system and orbits the Sun backwards.
An artist’s concept of a trans-Neptunian object(TNOs). The distant sun is reduced to a bright star at a distance of over 3 billion miles. Credit: NASA
Ordinarily, when planetary systems form, angular momentum forces everything to spin in the same direction. Hence why, when viewed from the celestial north pole, all the objects in our Solar System appear to be orbiting the Sun in a counter-clockwise direction. So when objects orbit the Sun in the opposite direction, an outside factor must be at play.
What’s more, the team compared the orbit of Niku with other high-inclination TNOs and Centaurs, and noticed that they occupy a common orbital plane and experience a clustering effect. As Dr. Matthew J. Holman – a professor at the Harvard-Smithsonian Center for Astrophysics and one of the researchers on the team – told Universe Today via email:
“The orbit of Niku is unusual in that it is nearly perpendicular to the plane of the Solar System. More than that, it is orbiting in the opposite direction of most Solar System bodies. Furthermore, there are a few bodies that share the same or orbital plane, with some orbiting prograde and some orbiting retrograde. That was unexpected.”
One possibility, which the team has already considered, was that this mysterious orbital pattern might be evidence of the much sought-after Planet Nine. This hypothetical planet, which is believed to exist at the outer edge of our Solar System (20 times further from our Sun than Neptune), if it exists, is also thought to be 10 times the size of the Earth.
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. Credit: ESO/Tomruen/nagualdesign
“Planet Nine seems to be gravitationally influencing another nearby population of bodies that are also orbiting nearly perpendicular to the plane of the solar system,” said Holman, “but those objects have much larger orbits that also come closer to sun at their closest approach. The similarity (perpendicular) nature of Niku’s orbit to that of the more distant population hints at a connection.”
Establishing such a connection based on the orbits of distant objects is certainly tempting, especially since no direct evidence of Planet Nine has been obtained yet. However, upon further analysis, the team concluded that Niku is too close to the rest of the Solar System for its orbit to be effected by Planet Nine.
In addition, the orbits of the clustered objects that circle the sun backwards along the same 110-degree plane path was seen as a further indication that something else is probably at work. Then again, it may very well be that there is a giant planet out there, and that it’s influence is mitigated by other factors we are not yet aware of.
“The population of objects in Niku-like orbits is not long-term stable,” said Holman. “We hoped that adding the gravitational influence of an object like Planet Nine might stabilize their orbits, but that turned out not to be the case. We are NOT ruling out Planet Nine, but we are not finding any direct evidence for it, at least with this investigation.”
Animated diagram showing the spacing of the Solar Systems planet’s, the unusually closely spaced orbits of six of the most distant KBOs, and the possible “Planet 9”. Credit: Caltech/nagualdesign
So for the time being, it looks like Planet Nine enthusiasts are going to have to wait for some other form of confirmation. But as Konstantin Batyagin – the Caltech astronomer who announced findings that hinted at Planet Nine earlier this year – was quoted as saying, this discovery is yet another step in the direction of a more complete understanding of the outer Solar System:
“Whenever you have some feature that you can’t explain in the outer solar system, it’s immensely exciting because it’s in some sense foreshadowing a new development. As they say in the paper, what they have right now is a hint. If this hint develops into a complete story that would be fantastic.”
Whatever the cause of Niku’s strange orbit (or those TNOs that share its orbital pattern) may be, it is clear that there is more going on in the outer Solar System than we thought. And with every new discovery, and every new object catalogued by astronomers, we are bettering our understanding of the dynamics that are at work out there.
In the meantime, perhaps we’ll just need to send some additional missions out that way. We have nothing to lose but our preconceived notions! And be sure to enjoy this video about this latest find, courtesy of New Scientist:
Special Guests:
Mike Brown is the Richard and Barbara Rosenberg Professor of Planetary Astronomy at CalTech. Konstantin Batygin is Assistant Professor of Planetary Science at CalTech. They’ll be here discussing their discovery of Planet 9 and what’s been happening since that amazing announcement.
We’ve had an abundance of news stories for the past few months, and not enough time to get to them all. So we’ve started a new system. Instead of adding all of the stories to the spreadsheet each week, we are now using a tool called Trello to submit and vote on stories we would like to see covered each week, and then Fraser will be selecting the stories from there. Here is the link to the Trello WSH page (http://bit.ly/WSHVote), which you can see without logging in. If you’d like to vote, just create a login and help us decide what to cover!
We record the Weekly Space Hangout every Friday at 12:00 pm Pacific / 3:00 pm Eastern. You can watch us live on Universe Today or the Universe Today YouTube page.
At this point, I think the astronomy textbook publishers should just give up. They’d like to tell you how many planets there are in the Solar System, they really would. But astronomers just can’t stop discovering new worlds, and messing up the numbers.
Things were simple when there were only 6 planets. The 5 visible with the unaided eye, and the Earth, of course. Then Uranus was discovered in 1781 by William Herschel, which made it 7. Then a bunch of asteroids, like Ceres, Vesta and Pallas pushed the number into the teens until astronomers realized these were probably a whole new class of objects. Back to 7.
Then Neptune in 1846 by Urbain Le Verrier and Johann Galle, which makes 8. Then Pluto in 1930 and we have our familiar 9.
But astronomy marches onward. Eris was discovered in 2005, which caused astronomers to create a whole new classification of dwarf planet, and ultimately downgrading Pluto. Back to 8.
It seriously looked like 8 was going to be the final number, and the textbook writers could return to their computers for one last update.
A predicted consequence of Planet Nine is that a second set of confined objects should also exist. These objects are forced into positions at right angles to Planet Nine and into orbits that are perpendicular to the plane of the solar system. Five known objects (blue) fit this prediction precisely. Credit: Caltech/R. Hurt (IPAC) [Diagram was created using WorldWide Telescope.]Astronomers, however, had other plans. In 2014, Chad Trujillo and Scott Shepard were studying the motions of large objects in the Kuiper Belt and realized that a large planet in the outer Solar System must be messing with orbits in the region.
This was confirmed and fine tuned by other astronomers, which drew the attention of Mike Brown and Konstantin Batygin. The name Mike Brown might be familiar to you. Perhaps the name, Mike “Pluto Killer” Brown? Mike and his team were the ones who originally discovered Eris, leading to the demotion of Pluto.
Brown and Batygin were looking to find flaws in the research of Trujillo and Shepard, and they painstakingly analyzed the movement of various Kuiper Belt Objects. They found that six different objects all seem to follow a very similar elliptical orbit that points back to the same region in space.
All these worlds are inclined at a plane of about 30-degrees from pretty much everything else in the Solar System. In the words of Mike Brown, the odds of these orbits all occurring like this are about 1 in 100.
Animated diagram showing the spacing of the Solar Systems planet’s, the unusually closely spaced orbits of six of the most distant KBOs, and the possible “Planet 9”. Credit: Caltech/nagualdesign
Instead of a random coincidence, Brown and Batygin think there’s a massive planet way out beyond the orbit of Pluto, about 200 times further than the distance from the Sun to the Earth. This planet would be Neptune-sized, roughly 10 times more massive than Earth.
But why haven’t they actually observed it yet? Based on their calculations, this planet should be bright enough to be visible in mid-range observatories, and definitely within the capabilities of the world’s largest telescopes, like Keck, Palomar, Gemini, and Hubble, of course.
The trick is to know precisely where to look. All of these telescopes can resolve incredibly faint objects, as long as they focus in one tiny spot. But which spot. The entire sky has a lot of tiny spots to look at.
Artist’s impression of Planet Nine, blocking out the Milky Way. The Sun is in the distance, with the orbit of Neptune shown as a ring. Credit: ESO/Tomruen/nagualdesign
Based on the calculations, it appears that Planet 9 is hiding in the plane of the Milky Way, camouflaged by the dense stars of the galaxy. But astronomers will be scanning the skies, and hope a survey will pick it up, anytime now.
But wait a second, does this mean that we’re all going to die? Because I read on the internet and saw some YouTube videos that this is the planet that’s going to crash into the Earth, or flip our poles, or something.
Nope, we’re safe. Like I just said, the best astronomers with the most powerful telescopes in the world and space haven’t been able to turn anything up. While the conspiracy theorists have been threatening up with certain death from Planet X for decades now – supposedly, it’ll arrive any day now.
But it won’t. Assuming it does exist, Planet 9 has been orbiting the Sun for billions of years, way way out beyond the orbit of Pluto. It’s not coming towards us, it’s not throwing objects at us, and it’s definitely not going to usher in the Age of Aquarius.
Once again, we get to watch science in the making. Astronomers are gathering evidence that Planet 9 exists based on its gravitational influence. And if we’re lucky, the actual planet will turn up in the next few years. Then we’ll have 9 planets in the Solar System again.
![A predicted consequence of Planet Nine is that a second set of confined objects should also exist. These objects are forced into positions at right angles to Planet Nine and into orbits that are perpendicular to the plane of the solar system. Five known objects (blue) fit this prediction precisely. Credit: Caltech/R. Hurt (IPAC) [Diagram was created using WorldWide Telescope.]](https://www.universetoday.com/wp-content/uploads/2016/01/p9_kbo_extras_orbits_2_1-580x326.jpg)
