In 2006, Pluto was stripped of its status as the ninth planet in the solar system thanks to the efforts of one astronomer, Michael Brown. Together with his colleagues, he discovered, and then other dwarf planets far beyond the orbit of Neptune. Thus, he proved that Pluto is not remarkable and big enough to be called a full-fledged planet. However, now Brown and our compatriot Konstantin Batygin are claiming that the new Planet 9 is already almost open ... and that all that remains is to see it.
Yes, yes, no one has yet seen the “almost open” ninth planet of the solar system! In fact, its discovery is the fruit of long observations of the orbits of other planets. According to Kepler and Newton, the place of each planet in the solar system is determined by its characteristics, mainly by mass. And if the orbit does not correspond to the parameters of the planet or is generally anomalous, then it is influenced by some other, no less massive object. The first planet discovered by mathematical equations, and not live observations, was - in 1846 it was found at a place calculated by the French mathematician Urbain Le Verrier.
Moreover, the planets can influence each other very actively - in the past of the solar system they traveled hundreds of millions of kilometers, approaching and moving away from the Sun. The gas giants were especially distinguished here. In young planetary systems, they absorb all the embryos of the planets and hang close to the star - as close as Mercury. Because of this, they become very hot and become unstable. Scientists call such planets "hot Jupiters" or "hot Neptunes" - depending on their mass and size.
Troubled History of the Solar System
However, Jupiter, the largest and most influential planet, changed everything in the solar system. Initially appearing at a distance of 5 to 10 from the Sun, it provoked active collisions of scattered material in the protoplanetary disk around the star. This gave impetus to the creation of other gas giants, such as Saturn or Neptune, at distances equally close to the Sun.
However, the newly formed planets behaved "ungratefully", following the laws of gravity - they pushed their "parent" closer to the Sun, into the modern orbit of Mars. Thus, Jupiter invaded inner part solar system. In other planetary systems, this part is the most saturated with matter and space objects. But the heavy tread of the mass of Jupiter scattered the embryos of planets and asteroids there, throwing them into the nuclear furnace of the Sun or throwing them to the outskirts of the system in the zone of modern and.
If not for Saturn, which connected Jupiter with an orbital resonance and did not bring it into a modern orbit, the gas giant could completely ruin the solar system, throwing out 99% of the planetary matter from it. However, his travels did not go unnoticed - so Neptune and Uranus changed their orbits, forming most of the long-period comets.
Ultimately, an unusual balance reigned in the solar planetary system - gas giants that form near the star ended up on the outskirts, and "solid planets" like the Earth migrated closer to the Sun. However, some astronomers believed that another planet was needed to achieve such a balance - and one massive enough to influence the large Neptune and Uranus. It, Planet X, was searched for by many astronomers for a century and a half - and it seems that Brown and Batygin finally got close to it.
History of the search for planet X
After Le Verrier calculated Neptune from perturbations in Uranus's orbit, astronomers found that even its presence did not explain the features of the ice giant's orbit. For some time they tried to find another planet that could influence the last large objects of the solar system - however, they managed to find only Pluto, which, by mass and direction of the orbit, could not disturb larger bodies in any way. The issue of Uranus-Neptune anomalies was finally resolved by "", who measured the mass of Neptune in 1989 and thereby found that there are no contradictions in the orbits.
By that time, the power of telescopes had grown significantly, which allowed astronomers to look into the depths of the solar system. Many trans-Neptunian objects have been discovered - dwarf planets and large asteroids, whose closest orbital point is further from the Sun than Neptune. So, in 2005, the already mentioned Eris was discovered, the second largest dwarf planet after Pluto. And in 2003 they found an object with diameters over 2 thousand kilometers, which moves away from the Sun at a distance of 1.4 × 10 11 km - further than any large trans-Neptunian object! It soon acquired a whole family of "sednoids", isolated trans-Neptunian objects with similar characteristics.
The ninth planet - where and why?
Observing the newly discovered planetoids, astronomers C. Trujillo and S. Sheppard, colleagues, discovered an interesting pattern. Most of them have elongated, comet-like orbits that briefly come "close" to the Sun, at a distance of 40 to 70 astronomical units, and then move away for hundreds or even thousands of years. And the larger the object, the stronger its removal. In addition, the sednoids deviated from the Sun in the same direction.
Such a coincidence could be an accident, if we are talking about simple comets - over the billions of years of the history of the solar system, they were scattered by all the major planets, especially the already mentioned "travelers" Jupiter, Uranus and Neptune. However, for such a coincidence in the deviations of large objects, a very large planet is needed, whose orbit would reach the Oort cloud.
Here Brown and Batygin distinguished themselves - by comparing the orbital characteristics of sednoids, they found mathematically that the probability of their random coincidence is only 0.007%. Scientists went further and made computer model, aimed at finding the characteristics of the planet, capable of changing the orbits of bodies located beyond Neptune. The data they received in January 2016 became the basis for the announcement of the pre-discovery of a new planet in the solar system.
Characteristics of Planet X
In his interviews, Brown claims that the probability of finding a new planet is 90%. However, until it is actually discovered, with the help of a telescope, it is too early to talk about the final discovery. Nevertheless, the calculated characteristics of Planet 9 have been published - they will be used in future searches.
- The orbital parameters of Planet X will be mirrored to those of the sednoids - the orbit of the planet will still be elongated and inclined relative to the plane of the main planets of the solar system, but directed in the opposite direction. Accordingly, the perihelion of the planet - the point of maximum approach to the Sun - will be 200 astronomical units at the nearest point, and the aphelion - the maximum distance - will reach 1200 astronomical units. This is even more than Sedna! A year on Planet 9 will last up to 20,000 Earth years, which is how long it may take to complete the entire orbit.
A planet distant from the Sun is difficult to detect - this requires telescopes operating in the infrared spectrum, or powerful optical devices that can capture even the smallest sun glare on the surface. On infrared telescopes, work will move faster, but errors are possible - and on optical telescopes, the result will be reliable, albeit at the cost of time. The WISE Infrared Orbiting Telescope, which conducted broadband surveys in 2009, has yet to detect Planet X, although it has provided fairly detailed images.
Therefore, Brown, Batygin and other astronomers are planning to find it using the Subaru telescop in the Hawaiian Islands, which is considered one of the largest and highest quality in the world - the diameter of its main mirror exceeds 8 meters! In addition, it is capable of operating both in the optical and in the infrared ranges of light. But even with such a tool, it will take scientists at least 5 years to put an end to the issue of Planet X.
Two American astronomers, one of whom is from Russia, shocked the scientific world on Tuesday after sensational news spread around the media: they discovered a ninth planet on the outskirts of the solar system! The first news about this was published by the California Institute of Technology, where both scientists work - and Mike, later - authoritative scientific journals science and nature.
“She will be the real ninth planet. Since ancient times, only two real planets have been found, and this will be the third. It's a big part of our solar system that has gone undetected, and that's amazing," says Brown.
It is reported that the planet was found by mathematical analysis of the perturbations experienced by many icy bodies from the so-called Kuiper Belt - a huge region of space beyond the orbit of Pluto. Calculations showed that the planet revolves around the Sun at a distance of 20 orbits of Neptune, its mass is 10 times the mass of the Earth.
Due to such a distance from the Sun, the planet is not visible and makes a complete revolution around the Sun in 10-20 thousand years.
“Although we were initially skeptical that this planet could exist, as we continued to explore its orbit, we became more and more confident that it really is there,” Batygin said.
The calculated mass of the object leaves no doubt that it can be attributed to the planet with full confidence, because it is 5 thousand times heavier than Pluto! Unlike a huge number of small objects in the solar system, such as dwarf planets, the ninth planet gravitationally dominates the extended region of the Kuiper Belt, where it rotates. Moreover, this area is much larger and the spaces dominated by all the other known planets of the solar system.
This, in Brown's words, makes it "the most planetary of the planets in the solar system."
Mike Brown and Konstantin Batygin
The work of scientists, which may become epoch-making, entitled "Evidence for a Distant Giant Planet in the Solar System" is published in the journal Astronomical Journal. In it, the authors find an explanation for many previously discovered features in the movement of icy bodies in the Kuiper Belt.
The search for the planet began in 2014, when a former student of Brown published a paper claiming that 13 of the most distant Kuiper Belt objects had similar oddities in their motion. Then a version of the existence of a nearby small planet was proposed. Brown then did not support this version, but continued the calculations. Together with Batygin, they began a year and a half project to study the orbits of these bodies.
Caltech/R.Hurt (IPAC)
Quite soon, Batygin and Brown realized that the orbits of six of these objects pass close to the same region of space, despite the fact that all orbits are different. “It's like looking at six clocks on six hands that are running at different speeds, and at that moment they show the same time. The probability of this is about 1/100,” explains Brown. In addition, it turned out that the orbits of all six bodies are inclined at an angle of 30 degrees to the plane of the ecliptic. “Actually, this could not be accidental. So we began to look for what formed these orbits, ”the astronomer explained.
Almost by accident, scientists noticed that if you put a heavy planet into the calculations,
whose perihelion is 180 degrees from the perihelion of these six bodies (that is, the Sun itself is between them), then its perturbations will explain the observed picture.
“It was a healthy reaction - such a geometry is impossible, orbits cannot be stable for a long time, because in the end this will lead to a collision of objects,” Batygin believes. However, the mechanism known in celestial mechanics as resonances of mean motions does not allow this to happen: objects, approaching each other, exchange energy and fly apart.
For every four revolutions of the ninth planet, there are nine revolutions of those same objects, and they never collide. As is often the case in astronomy, the hypothesis was confirmed when the assumption it predicted was confirmed. It turned out that the trans-Neptunian object Sedna, discovered in 2003 by Brown, Trujillo and Rabinowitz, and another similar object 2012 VP113 do deviate their orbits slightly where predicted. But the main assumption that came true is the existence, thanks to a heavy planet in the Kuiper Belt, of objects whose rotation plane is completely perpendicular to the plane of the solar system.
It turned out that over the past three years, astronomers have found at least four such objects whose orbits correspond to predictions.
Where did the planet hidden in the depths of the Kuiper Belt come from? Scientists believe that there were originally four cores in the solar system that formed Jupiter, Saturn, Uranus and Neptune. “However, there could have been five,” says Brown. This fifth protoplanet, coming too close to Jupiter or Saturn, could be thrown into a distant eccentric orbit.
According to scientists, if the planet is now close to its perihelion, you can look for it in past surveys of the sky. If she managed to leave, telescopes like 10-meter instruments at the Keck Observatory can catch her,
after all, the planet never approaches the Sun at a distance closer than 200 orbits of the Earth.
Among scientists there is no consensus about the discovery. , a body dynamics specialist from Nice, is sure that this planet exists. But not everyone thinks so. “I have seen many, many statements like this in my career. And they all turned out to be wrong, ”says Hal Levison, a planetary scientist at the Institute in Boulder (Colorado).
Until 2009, Pluto was considered the ninth planet of the solar system, discovered in 1930 also thanks to the analysis of the disturbances it created. Pluto has been demoted to a dwarf planet by the International Astronomical Union. Recently, some astronomers have created a movement to return it to planetary status following the discoveries made by the New Horizons probe.
One of the first interviews Konstantin Batygin gave to the correspondent of Gazeta.Ru.
- Konstantin, the search for bodies in the Kuiper Belt is not a very popular topic among astronomers, how many people are doing this?
“There are a little over a hundred people in the world, I think. It turned out that the most distant objects in the solar system, in physical space, look in the same direction. And the only theoretically correct model that we could construct is one where their orbits are held by the gravity of one planet.
- What are the prospects for finding a planet with telescopes?
“I think it can be done in the next two to five years. This requires knowledge of the orbit and sufficient observational time on telescopes. Knowing the orbit is what we've been doing in this article. To find it, you need to know where to look. At the moment, we know only the closest part of it.
— I know that you were born in Moscow. How did you end up in the USA?
- We lived in Russia until 1994, in Moscow I finished the 1st grade. We moved to Japan, lived there for six years, where I studied from grades 3 to 6, and skipped the second grade because I was too tall. Then he studied at the Russian school at the embassy in Tokyo. Moved to California in 1999 where I graduated high school, university and graduate school at Caltech.
- Good luck, we hope that your discovery will be confirmed, and we will see your last name in textbooks!
- Thanks.
Caltech scientists Michael Brown and Konstantin Batygin have provided evidence for the existence of a giant planet in the solar system, located even further from the Sun than Pluto.
The researchers reported that they have not yet been able to see it through a telescope. According to them, the planet was discovered when studying the movement of small celestial bodies in deep space. Weight heavenly body about 10 times the mass of the Earth, but scientists have yet to verify its existence.
Institute astronomers have only a rough idea of where the planet might be in the starry sky, and no doubt their suggestion will launch a campaign to find it.
"There are many telescopes on Earth theoretically capable of finding it. I really hope that now, after our announcement, people around the world will start looking for the ninth planet," said Michael Brown.
Elliptical orbit
According to scientists, space object is about 20 times farther from the Sun than Neptune, which is 4.5 billion km away.
Unlike the almost circular orbits of other planets in the Solar System, this object is supposed to move in an elliptical orbit, and a complete revolution around the Sun takes from 10 thousand to 20 thousand years.
Scientists have studied the movement of objects consisting mainly of ice in the Kuiper Belt. Pluto is in this belt.
The researchers noticed a certain location of some bodies in the Belt, in particular such large objects as Sedna and 2012 VP113. In their opinion, this can only be explained by the presence of an unknown large space object.
"All the most distant objects move in the same direction on an inexplicable trajectory, and we realized that the only explanation for this is the existence of a large, distant planet that holds them together as they orbit the Sun," Brown said.
Planet X
The idea of the existence of the so-called Planet X, located on the periphery of the solar system, has been discussed in scientific circles for more than 100 years. She is remembered and then forgotten.
The current speculation is of particular interest because of the study's lead author.
Brown specializes in finding distant objects, and it was his discovery of the dwarf planet Eris in the Kuiper Belt in 2005 that caused Pluto to lose planetary status a year later. Then it was assumed that Eris is slightly larger than Pluto, but now it has become clear that it is slightly smaller than it.
Researchers studying distant objects in the solar system have been speculating for some time on the possibility of a planet the size of Mars or Earth due to the size and shape of the planets in the Kuiper Belt. But until you can see the planet through a telescope, the idea of its existence will be perceived with skepticism.
The study by Michael Brown and Konstantin Batygin was published in the Astronomical Journal.
Scientists at the California Institute of Technology announced the discovery. So far, no one has seen a new object through a telescope. According to Michael Brown and Konstantin Batygin, the planet was discovered by analyzing data on the gravitational perturbation it exerts on other celestial bodies. The name has not yet been given to her, but scientists have been able to determine various parameters. It weighs 10 times more than the Earth. By chemical composition the new planet resembles two gas giants - Uranus and Neptune. By the way, it is similar to Neptune in its size, and is even further from the sun than Pluto, which, due to its modest size, has lost its status as a planet. Confirmation of the existence of a celestial body will take five years. Scientists have booked time at a Japanese observatory in Hawaii. The probability that their discovery is wrong is 0.007 percent. The new planet, if the discovery is recognized, will be the ninth in the solar system.
The solar system appears to have a new ninth planet. Today, two scientists announced evidence that a body nearly the size of Neptune-but as yet unseen-orbits the sun every 15,000 years. During the solar system's infancy 4.5 billion years ago, they say, the giant planet was knocked out of the planet-forming region near the sun. Slowed down by gas, the planet settled into a distant elliptical orbit, where it still lurks today.
The claim is the strongest yet in the centuries-long search for a "Planet X" beyond Neptune. The quest has been plagued by far-fetched claims and even outright quackery. But the new evidence comes from a pair of respected planetary scientists, Konstantin Batygin and Mike Brown of the California Institute of Technology (Caltech) in Pasadena, who prepared for the inevitable skepticism with detailed analyzes of the orbits of other distant objects and months of computer simulations. “If you say, ‘We have evidence for Planet X,’ almost any astronomer will say, ‘This again? These guys are clearly crazy.’ I would, too,” Brown says. Why is this different? This is different because this time we're right."
LANCE HAYASHIDA/CALTECH
Outside scientists say their calculations stack up and express a mixture of caution and excitement about the result. “I could not imagine a bigger deal if-and of course that’s a boldface ‘if’-if it turns out to be right,” says Gregory Laughlin, a planetary scientist at the University of California (UC), Santa Cruz. "What's thrilling about it is detectable."
Batygin and Brown inferred its presence from the peculiar clustering of six previously known objects that orbit beyond Neptune. They say there's only a 0.007% chance, or about one in 15,000, that the clustering could be a coincidence. Instead, they say, a planet with the mass of 10 Earths has shepherded the six objects into their strange elliptical orbits, tilted out of the plane of the solar system.
The orbit of the inferred planet is similarly tilted, as well as stretched to distances that will explode previous conceptions of the solar system. Its closest approach to the sun is seven times farther than Neptune, or 200 astronomical units (AUs). (An AU is the distance between Earth and the sun, about 150 million kilometers.) And Planet X could roam as far as 600 to 1200 AU, well beyond the Kuiper belt, the region of small icy worlds that begins at Neptune's edge about 30 AU.
If Planet X is out there, Brown and Batygin say, astronomers ought to find more objects in telltale orbits, shaped by the pull of the hidden giant. But Brown knows that no one will really believe in the discovery until Planet X itself appears within a telescope viewfinder. "Until there's a direct detection, it's a hypothesis-even a potentially very good hypothesis," he says. The team has time on the one large telescope in Hawaii that is suited for the search, and they hope other astronomers will join in the hunt.
Batygin and Brown published the result today in The Astronomical Journal. Alessandro Morbidelli, a planetary dynamicist at the Nice Observatory in France, performed the peer review for the paper. In a statement, he says Batygin and Brown made a "very solid argument" and that he is "quite convinced by the existence of a distant planet."
Championing a new ninth planet is an ironic role for Brown; he is better known as a planet slayer. His 2005 discovery of Eris, a remote icy world nearly the same size as Pluto, revealed that what was seen as the outermost planet was just one of many worlds in the Kuiper belt. Astronomers promptly reclassified Pluto as a dwarf planet-a saga Brown recounted in his book How I Killed Pluto.
Now, he has joined the centuries-old search for new planets. His method-inferring the existence of Planet X from its ghostly gravitational effects-has a respectable track record. In 1846, for example, the French mathematician Urbain Le Verrier predicted the existence of a giant planet from irregularities in the orbit of Uranus. Astronomers at the Berlin Observatory found the new planet, Neptune, where it was supposed to be, sparking a media sensation.
Remaining hiccups in Uranus's orbit led scientists to think that there might yet be one more planet, and in 1906 Percival Lowell, a wealthy tycoon, began the search for what he called "Planet X" at his new observatory in Flagstaff, Arizona. In 1930, Pluto turned up-but it was far too small to tug meaningfully on Uranus. More than half a century later, new calculations based on measurements by the Voyager spacecraft revealed that the orbits of Uranus and Neptune were just fine on their own: No Planet X was needed.
Yet the allure of Planet X persisted. In the 1980s, for example, the researchers proposed that an unseen brown dwarf star could cause periodic extinctions on Earth by triggering fusillades of comets. In the 1990s, scientists invoked a Jupiter-sized planet at the solar system's edge to explain the origin of certain oddball comets. Just last month, researchers claimed to have detected the faint microwave glow of an outsized rocky planet some 300 AU away, using an array of telescope dishes in Chile called the Atacama Large Millimeter Array (ALMA). (Brown was one of many skeptics, noting that ALMA's narrow field of view made the chances of finding such an object vanishingly slim.)
Brown got his first inkling of his current quarry in 2003, when he led a team that found Sedna, an object a bit smaller than both Eris and Pluto. Sedna's odd, far-flung orbit made it the most distant known object in the solar system at the time. Its perihelion, or closest point to the sun, lay at 76 AU, beyond the Kuiper belt and far outside the influence of Neptune's gravity. The implication was clear: Something massive, well beyond Neptune, must have pulled Sedna into its distant orbit.
(DATA)JPL; BATYGIN AND BROWN/CALTECH; (DIAGRAM) A. CUADRA/ SCIENCE
That something didn't have to be a planet. Sedna’s gravitational nudge could have come from a passing star, or from one of the many other stellar nurseries that surrounded the nascent sun at the time of the solar system’s formation.
Since then, a handful of other icy objects have turned up in similar orbits. By combining Sedna with five other weirdos, Brown says he has ruled out stars as the unseen influence: Only a planet could explain such strange orbits. Of his three major discoveries-Eris, Sedna, and now, potentially, Planet X-Brown says the last is the most sensational. Killing Pluto was fun. Finding Sedna was scientifically interesting,” he says. "But this one, this is head and shoulders above everything else."
Brown and Batygin were nearly beaten to the punch. For years, Sedna was a lone clue to a perturbation from beyond Neptune. Then, in 2014, Scott Sheppard and Chad Trujillo (a former graduate student of Brown’s) published a paper describing the discovery of VP113, another object that never comes close to the sun. Sheppard, of the Carnegie Institution for Science in Washington, D.C., and Trujillo, of the Gemini Observatory in Hawaii, were well aware of the implications. They began to examine the orbits of the two objects along with 10 other oddballs. They noticed that, at perihelion, all came very near the plane of solar system in which Earth orbits, called the ecliptic. In a paper, Sheppard and Trujillo pointed out the peculiar clumping and raised the possibility that a distant large planet had herded the objects near the ecliptic. But they didn't press the result any further.
Later that year, at Caltech, Batygin and Brown began discussing the results. Plotting the orbits of the distant objects, Batygin says, they realized that the pattern that Sheppard and Trujillo had noticed "was only half of the story." Not only were the objects near the ecliptic at perihelia, but their perihelia were physically clustered in space (see diagram, above).
For the next year, the duo secretly discussed the pattern and what it meant. It was an easy relationship, and their skills complemented each other. Batygin, a 29-year-old whiz kid computer modeler, went to college at UC Santa Cruz for the beach and the chance to play in a rock band. But he made his mark there by modeling the fate of the solar system over billions of years, showing that, in rare cases, it was unstable: Mercury may plunge into the sun or collide with Venus. "It was an amazing accomplishment for an undergraduate," says Laughlin, who worked with him at the time.
Brown, 50, is the observational astronomer, with a flair for dramatic discoveries and the confidence to match. He wears shorts and sandals to work, puts his feet up on his desk, and has a breeziness that masks intensity and ambition. He has a program all set to sift for Planet X in data from a major telescope the moment they become publicly available later this year.
Their offices are a few doors down from each other. "My couch is nicer, so we tend to talk more in my office," Batygin says. "We tend to look more at data in Mike's." They even became exercise buddies, and discussed their ideas while waiting to get in the water at a Los Angeles, California, triathlon in the spring of 2015.
First, they winnowed the dozen objects studied by Sheppard and Trujillo to the six most distant-discovered by six different surveys on six different telescopes. That made it less likely that the clumping might be due to an observation bias such as pointing a telescope at a particular part of the sky.
Batygin began seeding his solar system models with Planet X’s of various sizes and orbits, to see which version best explained the objects’ paths. Some of the computer runs took months. A favored size for Planet X emerged-between five and 15 Earth masses-as well as a preferred orbit: antialigned in space from the six small objects, so that its perihelion is in the same direction as the six objects' aphelion, or farthest point from the sun. The orbits of the six cross that of Planet X, but not when the big bully is nearby and could disrupt them. The final epiphany came 2 months ago, when Batygin's simulations showed that Planet X should also sculpt the orbits of objects that swoop into the solar system from above and below, nearly orthogonal to the ecliptic. "It sparked this memory," Brown says. "I've seen these objects before." It turns out that, since 2002, five of these highly inclined Kuiper belt objects have been discovered, and their origins are largely unexplained. "Not only are they there, but they are in exactly the places we predicted," Brown says. "That is when I realized that this is not just an interesting and good idea-this is actually real."
Sheppard, who with Trujillo had also suspected an unseen planet, says Batygin and Brown “took our result to the next level. …They got deep into the dynamics, something that Chad and I aren’t really good with. That's why I think this is exciting."
Others, like planetary scientist Dave Jewitt, who discovered the Kuiper belt, are more cautious. The 0.007% chance that the clustering of the six objects is coincidental gives the planet claim a statistical significance of 3.8 sigma-beyond the 3-sigma threshold typically required to be taken seriously, but short of the 5 sigma that is sometimes used in fields like particle physics. That worries Jewitt, who has seen plenty of 3-sigma results disappear before. By reducing the dozen objects examined by Sheppard and Trujillo to six for their analysis, Batygin and Brown weakened their claim, he says. "I worry that the finding of a single new object that is not in the group would destroy the whole edifice," says Jewitt, who is at UC Los Angeles. "It's a game of sticks with only six sticks."
(IMAGES) WIKIMEDIA COMMONS; NASA/JPL-CALTECH; A. CUADRA/ SCIENCE ; NASA/JHUAPL/SWRI; (DIAGRAM) A. CUADRA/ SCIENCE
At first blush, another potential problem comes from NASA’s Widefield Infrared Survey Explorer (WISE), a satellite that completed an all-sky survey looking for the heat of brown dwarfs-or giant planets. It ruled out the existence of a Saturn-or-larger planet as far out as 10,000 AU, according to a 2013 study by Kevin Luhman, an astronomer at Pennsylvania State University, University Park. But Luhman notes that if Planet X is Neptune-sized or smaller, as Batygin and Brown say, WISE would have missed it. He says there is a slim chance of detection in another WISE data set at longer wavelengths-sensitive to cooler radiation-which was collected for 20% of the sky. Luhman is now analyzing those data.
Even if Batygin and Brown can convince other astronomers that Planet X exists, they face another challenge: explaining how it ended up so far from the sun. At such distances, the protoplanetary disk of dust and gas was likely to have been too thin to fuel planet growth. And even if Planet X did get a foothold as a planetesimal, it would have moved too slowly in its vast, lazy orbit to hoover up enough material to become a giant.
Instead, Batygin and Brown propose that Planet X formed much closer to the sun, alongside Jupiter, Saturn, Uranus, and Neptune. Computer models have shown that the early solar system was a tumultuous billiards table, with dozens or even hundreds of planetary building blocks the size of Earth bouncing around. Another embryonic giant planet could easily have formed there, only to be booted outward by a gravitational kick from another gas giant.
It’s harder to explain why Planet X didn’t either loop back around to where it started or leave the solar system entirely. But Batygin says that residual gas in the protoplanetary disk might have exerted enough drag to slow the planet just enough for it to settle into a distant orbit and remain in the solar system. That could have happened if the ejection took place when the solar system was between 3 million and 10 million years old, he says, before all the gas in the disk was lost into space.
Hal Levison, a planetary dynamicist at the Southwest Research Institute in Boulder, Colorado, agrees that something has to be creating the orbital alignment Batygin and Brown have detected. But he says the origin story they have developed for Planet X and their special pleading for a gas-slowed ejection add up to "a low-probability event." Other researchers are more positive. The proposed scenario is plausible, Laughlin says. "Usually things like this are wrong, but I'm really excited about this one," he says. "It's better than a coin flip."
All this means that Planet X will remain in limbo until it is actually found.
Astronomers have some good ideas about where to look, but spotting the new planet won't be easy. Because objects in highly elliptical orbits move fastest when they are close to the sun, Planet X spends very little time at 200 AU. And if it were there right now, Brown says, it would be so bright that astronomers probably would have already spotted it.
Instead, Planet X is likely to spend most of its time near aphelion, slowly trotting along at distances between 600 and 1200 AU. Most telescopes capable of seeing a dim object at such distances, such as the Hubble Space Telescope or the 10-meter Keck telescopes in Hawaii, have extremely tiny fields of view. It would be like looking for a needle in a haystack by peering through a drinking straw.
One telescope can help: Subaru, an 8-meter telescope in Hawaii that is owned by Japan. It has enough light-gathering area to detect such a faint object, coupled with a huge field of view-75 times larger than that of a Keck telescope. That allows astronomers to scan large swaths of the sky each night. Batygin and Brown are using Subaru to look for Planet X-and they are coordinating their efforts with their erstwhile competitors, Sheppard and Trujillo, who have also joined the hunt with Subaru. Brown says it will take about 5 years for the two teams to search most of the area where Planet X could be lurking.
Subaru Telescope, NAOJ
If the search pans out, what should the new member of the sun's family be called? Brown says it's too early to worry about that and scrupulously avoids offering up suggestions. For now, he and Batygin are calling it Planet Nine (and, for the past year, informally, Planet Phattie-1990s slang for "cool"). Brown notes that neither Uranus nor Neptune-the two planets discovered in modern times-ended up being named by their discoverers, and he thinks that that's probably a good thing. It's bigger than any one person, he says: "It's kind of like finding a new continent on Earth."
He is sure, however, that Planet X-unlike Pluto-deserves to be called a planet. Something the size of Neptune in the solar system? Don't even ask. "No one would argue this one, not even me."
MOSCOW, March 17 - RIA Novosti, Tatyana Pichugina. The ninth planet from the Sun will be discovered in the next decade, according to American astronomers. It moves in an elliptical orbit in the Kuiper Belt, a little-studied region far beyond Neptune. The new data leaves little doubt that a super-Earth exists in the solar system.
Who draws the orbits
Man has been studying the solar system for more than a millennium, but there are still enough white spots. For example, in the 1980s, astronomers were enthusiastically looking for Nemesis - a dark star, partner of the Sun. It was assumed that it could cause an ecological catastrophe on Earth 65 million years ago, when the dinosaurs died.
Pluto used to be considered the ninth planet of the solar system, but in 2006 it was deprived of this status, reclassified as a dwarf planet, in fact, an asteroid. The initiator was the American astronomer Michael Brown from the California Institute of Technology (USA). All this he described in the book "How I killed Pluto and why it was inevitable."
The search for a killer star ended in nothing, but ten years later they proved the existence of the Kuiper belt - an area where ice fragments of matter left after the formation of the solar system are concentrated. The largest are about nine hundred kilometers. In total, about two thousand celestial bodies were discovered there.
Brown purposefully explores the Kuiper belt, looking for other trans-Neptunian objects - that is, those that are further from the Sun than Neptune. He discovered 27 celestial bodies, including the dwarf planets Sedna and Eridu.
Among the trans-Neptunian objects there are anomalous ones, whose orbits are very elongated: their major semi-axes extend over 250 astronomical units (distances from the Sun to the Earth), however, the points of the orbits closest to the star are in the same area. To explain this oddity, Brown, along with his Caltech colleague Konstantin Batygin, put forward a hypothesis in 2016 about the existence of another planet in the outskirts of the solar system.
© CC0 / nagualdesign / CaltechSome bodies in the far Kuiper belt have elongated orbits, with perihelia concentrating in one place. The dotted line indicates the orbit of the hypothetical planet ninth predicted in 2016
© CC0 / nagualdesign / Caltech
Some bodies in the far Kuiper belt have elongated orbits, with perihelia concentrating in one place. The dotted line indicates the orbit of the hypothetical planet ninth predicted in 2016
Out of competition
Significant forces were thrown in search of a new planet, amateur astronomers were connected - to no avail. Nevertheless, the hypothesis was not discarded, on the contrary, now it seems even more reasonable. “We were worried that there would be a simpler or more natural explanation for the anomalies we see in the data, and that the Planet Nine hypothesis would soon be irrelevant. But this did not happen. The hypothesis has stood the test of time quite successfully,” writes Konstantin Batygin in his blog.
There are only two alternative versions explaining the anomalies in the orbits of the most distant Kuiper belt objects. The first is observational error. A new one by Brown and Batygin, published in January in The Astronomical Journal, is devoted to its analysis. Scientists have calculated the probability with which the orbits of these bodies look exactly as they are seen now, thanks to an error. The result is only two tenths of a percent. Conclusion: the observed oddities are statistically significant.
Another alternative is the existence of another massive disk in the solar system, consisting of icy planetesimals - the remnants of a protoplanetary disk whose gravity pulls the orbits of trans-Neptunian objects in the same way as an entire planet would. But, notes Michael Brown, this scenario is even more complex.
Super-Earth in the solar system?
The results of two years of searching for the ninth planet are summed up by Brown and Batygin, prepared jointly with colleagues from the University of Michigan for the journal "Physics Reports". Scientists reanalyzed all the facts, refined the characteristics of the hypothetical planet, performed numerical simulations and provided convincing evidence of its existence.
The ninth planet is two times smaller in all respects than it seemed three years ago, explains Batygin. The semi-major axis of its orbit is approximately 400-500 astronomical units, the eccentricity is 0.15-0.3 (an indicator of the contraction of the ellipse), the inclination is 20 degrees. The best simulation results are obtained when the mass of the planet is five times that of the Earth. In any case, ten Earth masses is the ceiling. For comparison: Neptune is 17.2 times heavier.
Judging by the characteristics, the ninth planet is very similar to a super-Earth - a special class of exoplanets often observed around other stars. Perhaps this celestial body did not really form here, but was captured by the Sun at the time of its approach to another star system. However, it is too early to raise the question of the origin of a hypothetical planet.
Wanderer's shelter
The magnitude, or brightness, of the new member of the planetary family is very small - 24-25 magnitudes. This is at the limit of the capabilities of earth technology. The object could have been detected by the Pan-STARRS telescope scanning the entire sky. However, there is a difficulty - the most distant point of the orbit of the celestial body of interest to us may intersect the plane milky way where there is a high concentration of stars. Against their background, it is difficult to distinguish anything.
