A planet larger than Earth may be hiding at the far fringes of the solar system/Michael D. LeMonique
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Several distant icy bodies orbiting the Sun in strange orbits have led some scientists to hypothesize that there are more planets in the Solar System than we know.
The evidence, they say, supports the idea that beyond Neptune resides at least one "super-Earth," that is, a planet whose mass may be up to ten times that of Earth.
These bodies may be too distant and dim for telescopes we have today to see, but future observations may locate them, if they are there.
Something very strange seems to be happening beyond Pluto's orbit. Astronomers have known for twenty years that this tiny former planet is not alone at the edge of the solar system: Pluto is part of a vast cloud of icy objects known collectively as the Kuiper Belt. But unlike their fellow travelers, and unlike the planets and most of the asteroids orbiting the Sun between Mars and Jupiter, a handful of Kuiper Belt Objects, or - for short - KBOs, have very strange orbits. First of all, they orbit the sun in unusually elongated orbits, which contrasts with the nearly circular (?) orbits of most planetary bodies.
These rogue objects, which range from 4 to 12 depending on who's counting, have another orbital quirk. Like most KBOs, the members of this group also orbit the Sun in an orbit inclined at an angle to the pancake-like plane where the planets reside. During part of their lap time, they rise above the "labiba", then dive through it and continue their journey under it the rest of the time. However, unlike their frozen brethren, these objects all pass through the planetary plane at the same time they reach the point closest to the Sun in their orbit (called the perihelion) and swing past it.
Or in other words, if we use a term that is not common in the mouths of many astronomers, their perihelion angles (AOP) are remarkably similar to each other. "Normally," says Scott Shepherd, a planetary scientist at the Carnegie Institution for Science, "we would expect that over the course of the solar system's existence, the perihelion angles would be randomly distributed." It cannot be ruled out that it was coincidence that brought this small group of entities together so that their AOPs are so similar. Such a case can occur completely at random, with a probability of less than a few percent at a given time. The probability of this is similar to the probability of a coin falling 10 times in a row on a "tree": certainly not usual, but very far from impossible.
However, when the coin lands on the same side 10 times in a row, it may be tilted - and the same goes for the heavenly bodies. It is possible that something forced them to manage in this strange arrangement, like for example a huge and unknown planet, whose mass is considerably greater than the mass of the Earth. It is therefore possible that a super-Earth (a term used to describe planets whose mass is only about 10 times greater than the mass of the Earth) is hidden on the outskirts of the solar system. If such a celestial object - sometimes jokingly called "Planet X" - is indeed hiding there, it may orbit the Sun at a distance at least 10 times the radius of Neptune's orbit. At such a distance it will be too distant and dim to be detected by any telescope currently available to us. However, its considerable mass must have a gravitational effect on the other bodies in the solar system, an effect that may explain the strange orbits that astronomers have discovered.
"We still don't have firm proof that there is a planet-mass body out there," says Nathan Kaiev, a planetary formation theorist at the Carnegie Institution. "But something strange is happening there that we don't understand." Meanwhile, a growing number of astronomers are beginning to believe the previously discredited idea that Planet X, a super-Earth, does exist in the solar system.
However, as Kaiev says, the evidence for the existence of a hidden planet is far from solid. Many astronomers still doubt the idea, and even astronomers who raised it as a hypothesis admit they are still not entirely convinced. The history of astronomy is littered with mysterious unseen planets, whose existence scientists inferred due to quirks in the orbits of other objects. Some of them turned out to be important discoveries. Others were false alarms. We may be further than we thought from really knowing our solar system. If Planet X is indeed there, it would require a fundamental rewriting of several important chapters in the history of the solar system.
The route to discover hidden worlds
The first search for a hidden planet orbiting the Sun occurred in the early 19th century, when scientists became increasingly convinced that Uranus, discovered by chance in 1781 by musician-turned-astronomer William Herschel, was not orbiting the Sun in the exact orbit it was supposed to according to the law of gravity. of Newton. Some scientists have speculated that the force of gravity exerted by a large, as-yet-undiscovered planet is the cause. Indeed, in 1846 the German astronomer Johann Galle noticed the gas giant Neptune, basically in the place where his French colleague Urban Le Verrier had calculated that it should be found. (There is good evidence that in fact Galileo had already seen Neptune in 1612 with his small, crude telescope, but thought it was a star rather than a planet.)
At the beginning of the first decade of the 20th century, Percival Lowell, a Boston socialite, began to search for another hidden planet. He did this in his private observatory in Flagstaff, Arizona. This time the evidence came from orbital deviations of both Uranus and Neptune, and they hinted at the existence of another giant unseen planet. In the early 30s, one of the assistants at the Lovell Observatory, named Clyde Tombo, did indeed discover a planet in the place where the calculations predicted, more or less, a sort of repetition of the discovery of Neptune. "The ball is apparently larger than Jupiter, is 4,000,000,000 miles away and is fulfilling predictions," declared the New York Times on March 14, 1930.
But that was not the case. In the following decades, it became clear that Pluto is very far from the size of Jupiter and is actually smaller than the Earth's moon. Its tiny gravity has no ability to explain the deviations in the orbits of Neptune and Uranus, and that's a good thing, because they disappeared after further examination of the data. In this respect, Pluto was a false alarm.
However, from the broader aspect of the picture, his discovery was extraordinarily important. In the 80s, scientists began to suspect that Pluto was not just a derelict planet orbiting the sun alone in the icy outskirts of the solar system, but simply the brightest member of a large and rich group that resides in the region known as the Kuiper Belt. In 1992, the first object in the Kuiper belt (besides Pluto, of course) was observed by a telescope in Hawaii, and since then the observers have reached about 1,500 such objects. The discovery of Eris in 2005, comparable to Pluto in diameter but considerably larger than it in mass, threatened a flood of discoveries that would require adding several planets to the number of nine that were known until then. This threat pushed the International Astronomical Union in 2006 to downgrade Pluto from a planet to a dwarf planet.
reorganize the solar system
The very discovery of the Kuiper Belt strengthens the idea of the search for Planet X, because it helps explain how such a celestial object found itself so far from the Sun and the eyes of our telescopes. Computer simulations suggest that the icy bodies of the Kuiper Belt formed near where Neptune is today. Something had to throw them away (or scatter them, if we use the technical term) to their present locations. This observation led astronomers to hypothesize that this dispersal occurred during the chaotic period that followed immediately after the young planets coalesced out of the "preplanetary disk," which contained gas and dust and swirled around the nascent Sun. During this unstable period, it is likely that Jupiter, Saturn, Uranus and Neptune deviated from their original orbits and wandered hundreds of millions of kilometers away. On their way to their new orbits, they gravitated the objects that now reside in the Kuiper Belt out to the outskirts of the Solar System. Some simulations even suggest the past existence of a fifth gas giant that was completely ejected from the solar system while the others settle into their orbits.
The history of astronomy is littered with mysterious unseen planets, whose existence scientists inferred due to quirks in the orbits of other objects.
It is easy to assume that if there existed in the solar system at that time a planet suitable for the definition of a super-Earth, it too was thrown out in that era of violent instability. Super-Earths have been found to be quite common among the approximately 2,000 planets discovered in the last decades around other suns. It is therefore logical to assume that perhaps such a planet also orbited our sun. From this point of departure, says Ben Bromley from the University of Utah, who worked in collaboration with Scott Kenyon from the Harvard-Smithsonian Center for Astrophysics, "we ran several computer simulations that checked what might happen to a super-Earth that was diverted from the area where Jupiter and Saturn are today." In most runs, they found that such a planet would be thrown into a highly elliptical orbit, which would stretch over time until the planet was completely ejected from the solar system. But if the dispersal occurred early enough, in the first 10 million years or so after the planets formed, and before the preplanetary gas cloud dissipated, Bromley says, "the large planet may have reacted [via gravity] with the gas and settled into the outskirts of the solar system in a circular orbit, More or less."
This scenario is one way to create a Planet X, the kind that Wall set out to look for in the early 20th century, and that Gale and Le Verrier found in their collaboration when they discovered Neptune half a century earlier. Another way, Kenyon and Bromley discovered, is if this super-Earth was formed where it is, at a distance of about 200 astronomical units from the Sun, that is, 200 times the distance between the Earth and the Sun, which is about 150 million kilometers. (Neptune, on the other hand, orbits the Sun at a distance of about 30 astronomical units from it.) Such local formation is only possible if enough material to form the planet, rocks and ice blocks the size of pebbles, orbited the Sun so far away.
There is no direct evidence that this was the case in our solar system, but there is fairly strong evidence that it happened around other stars very similar to the Sun. "If you look at nearby sun-like stars," Kenyon says, "some of them have disks of material fragments that extend to distances of about 200 astronomical units from the star itself. In other words, this is not an unprecedented event." And while there is no proof that super-Earths actually formed at such a distance around those nearby stars, he says, "at least the basic ingredients are there." All these simulations were pure speculation when Kenyon and Bromley started running them about ten years ago. No one saw any hint that a Super-Earth actually existed there.
Illustration of distant bodies beyond the asteroid belt and even beyond the Kuiper belt. (Sources: The list of trans-Neptunian bodies of the Center for Minor Planets in the International Astronomical Union (data of Kuiper belt bodies); Scott S. Shepherd, Carnegie Institution for Science (data of distant objects in the solar system ); illustration: Jean-William Tulip)
most distant bodies
Welcome workshop
The situation began to change with the discovery of Sedna. In 2003, Mike Brown from the California Institute of Technology (Caltech), together with his two colleagues, discovered the celestial body, which is perhaps the strangest object discovered in the solar system up to that time. It was an icy body, now estimated to be about 1,000 kilometers in diameter, similar in many ways to Pluto, Eris and other Kuiper belt bodies. But his trajectory was unlike anything seen before. Sedna never approaches the Sun to a distance smaller than 76 astronomical units, i.e. to a distance twice as large and more than Neptune. It has a very elongated orbit that takes 11,400 years to complete, and it takes it to a distance of more than 930 AU at its farthest point, 31 times that of Neptune.
"Sedna was a real surprise," says one of the co-discoverers, Chad Trujillo, who now works at the Gemini Observatory in Hawaii, "because it had no explanation." Its stretched, elongated orbit resembled the long-period orbits of comets, but comets have orbits firmly anchored by the gravity of one of the giant planets. But it seems that Sedna's orbit is not anchored to any planet. "No one thought such an object could exist at all," says Trujillo, "and no one had an explanation for how it got there."
During the following ten years, ten more smaller bodies were discovered, whose orbits are elongated and which do not come close to Neptune. This in itself is not worth mentioning: none of them moves in an extreme orbit like that of Sedna, neither in the shape of the orbit nor in the great distance of the perihelion, the closest point to the sun. But all of them, including Sedna, had similar and unusual perihelion angles, that orbital parameter that describes the distance to which the body reaches in perihelion above or below the plane of the solar system. And it looks… weird.
Things got much weirder in 2014 when Trujillo and Shepard announced in the journal Nature that after a search that lasted about ten years, they discovered another sedna-like body, which was about half the size of sedna itself. "If you're a biologist," says Trujillo, "and you find some strange creature, you're pretty sure there must be other creatures like it." It's the same in astronomy, he says: unless the first creature was a completely accidental thing. "Maybe this single body ended up in this orbit by accident, for reasons we don't understand," he says, "but you can't really know until you find another one." And now they have found.
No one thought such an object could exist at all," says Chad Trujillo, "and no one had an explanation for how it got there.
Previously known as 2012 VP113, this celestial object orbits the Sun in a stretched, or eccentric, orbit every 4,300 years. Its perihelion is at a distance of 80 astronomical units, and its aphelion, the farthest point in its orbit from the Sun, at a distance of 446 astronomical units. Like Sedna, 2012 VP113 is also gravitationally completely separate from Neptune. And most important of all: its perihelion angle is very similar to that of Sedna, as well as to the angle of a handful of other objects in the Kuiper belt, which are less similar to Sedna. This last factor led the authors to write a provocative line, which is well hidden at the end of the article in Nature: "This suggests," wrote Trujillo and Shepherd, "the existence of a high-mass 'disturber' in the outer solar system." They hypothesized that the "interferer" might be a super-Earth, orbiting the Sun in an orbit up to 250 AU away from it, and that its gravity might affect the smaller objects and synchronize their perihelion angles. "I don't think that until then anyone had really thought seriously about a large planet that had not yet been discovered," says Meg Schwamb of Yale University. "But Trujillo and Shepherd's paper really brought the idea to the surface."
Then, in September 2014, an article in one of the monthly journals of the British Royal Astronomical Society, by two relatively unknown Spanish astronomers, the brothers Raul and Carlos de la Fuente Marcos, from the Complutense University in Madrid, stirred up the field. Based on the orbits of Sedna, 2012 VP113 and smaller bodies, the brothers argued that there may be more than one super-Earth. Their analysis "convincingly suggests" that there are at least two planets beyond Pluto. "Our calculations, which have not yet been published," says Raul, "suggest that the putative planets may have at least twice the mass of Earth, but probably no more than 15."
Like Shepard and Trujillo, the de la Fuente Carlos brothers also do not claim certain predictions. All in all, both teams claim that the existence of a super-Earth is plausible. However, if it does exist, it would undermine the confidence of astronomers that they fully understand our solar system.
Muscle doubts and exist
Although the existence of Planet X is a tempting explanation for the oddities of Sedna and her crew, it is not the only possibility. Another explanation, says Hal Levinson, a planet formation theorist at the Southwest Research Center, is that 2012 VP113 and the others were thrown into their unique orbits while the Sun was still part of the original cluster from which it formed, a cluster of thousands of stars that all coalesced from a cloud. Single gas. Before the cluster broke up, these stars were close enough to distort the orbits of objects on the outskirts of the solar system and send them inward on elongated, stretched orbits. And perhaps, Sheppard says, the orbits were stretched as a result of galactic tidal forces, that is, stronger pulling forces in a certain direction as the Sun passed near dense areas in its orbit around the center of the Milky Way. "We ran a few computer simulations like this," says Shepherd, "and we didn't see anything. So it doesn't seem like this idea is reasonable, but there are many other similar options."
Any of these effects would have sent these objects into their elongated orbits, but only the super-Earth hypothesis gives them such coordinated perihelion angles. On the other hand, it is possible that these are complete coincidences. Shepherd and Trujillo mention 12 objects in their article. The number may sound high, but considering that the Kuiper belt contains millions of objects, Shepherd says, "this number is statistically borderline."
And the arguments for the existence of Planet X, based on the strange orbits of Sedna and her group, weaken even more if we accept the results of Schwamb and her colleague Ramon Brasser from the Tokyo Institute of Technology. "Recent work we've done," Schwamb says, "shows that there are actually only four workshop-like bodies." The rest of the 12 bodies do not come very close to Neptune, she says, but they come close enough to feel its gravity. Neptune itself may be the X planet which explains the match between their perihelion angles. And if 12 bodies are a statistically borderline case, even more so if it's four. However, the meaning of the term "borderline" in the world of science is slightly different from its meaning in everyday life. "The match between the remaining four objects," says Brasser, "may happen by chance only XNUMX percent of the time." But slim chances are no proof of the matter. "Just because such a planet is possible," Schwamb says, and she does agree that it is possible, "does not prove its existence."
Planetary scientists have learned this lesson more than once. Physicist Richard Muller of the University of California, Berkeley, believed in the 80s that he could explain the mass extinctions of species on Earth by hypothesizing that at a distance of 10,000 astronomical units from the Sun, or about 1.5 light years, a dim star or brown dwarf, a mass body Smaller than a star but bigger than a planet. Once every 26 million years, more or less, so the hypothesis claimed, the object named Nemesis [the goddess of vengeance in Greek mythology - the editors] flies a group of comets from the Oort cloud, a shell, still assumed, of icy bodies that surrounds the solar system, far Much more than a workshop or any other body that astronomers have ever seen. These Oort comets fall in the direction of the sun. Some of them collide with the Earth, and thus a considerable proportion of the species on our planet disappeared.
Three images showing the motion of a dim object that astronomers call a sedna. Courtesy of NASA, JPL and Calcutta
Three images, taken about an hour and a half apart at the Plummer Observatory in California, show the movement of a dim object that astronomers call a sedna. The strange orbits of Sedna and similar bodies suggest the existence of a hidden planet beyond Pluto. (Courtesy of NASA, JPL and Calcutta)
But like the arguments heard today for the existence of Planet X, Mueller's theory was only barely plausible, and the searchers for Nemesis came up empty-handed time and time again. Then, John Mattis and Daniel Whitmire, both of the University of Louisiana at Lafayette, hypothesized the existence of a Jupiter-sized planet at the very far edge of the solar system. They did this to explain an apparent excess of long-period comets coming from a certain direction in the sky. "It was an article in the scientific literature," Schwamb says, a phrase in the language of scientists that means "I didn't 'buy it' in the first place." Indeed, NASA's infrared space telescope, WISE, found nothing. "We should be able to see a Jupiter-sized object up to 30,000 or maybe 40,000 AU from the Sun," says Kevin Lohman of Pennsylvania State University, who conducted the search, "and a Saturn-sized object up to 10,000 or maybe 15,000 AU from the Sun. .” They found nothing. Planet X, which is about the size of a super-Earth, should be much closer, but also much dimmer, so it cannot be seen in this survey.
Are we there or not?
With only 12 unusual objects at their disposal, planetary scientists cannot determine at this stage whether or not there is a super-Earth in our solar system. The only thing they can say is that the hypothesis fits the observations. Identifying additional objects with similar trajectory characteristics is essential for this. That's why astronomers are so excited about a new object that was announced in November 2015. V774104 has a perihelion farther from the Sun than even Sedna's. It is too early to know whether its orbit confirms or contradicts the possible existence of a giant, unknown planet, says Shepherd, who headed the discovery team. It's also too early to say anything about the 40 or so other distant objects that Shepard's team found at the time in "the deepest and most extensive survey ever conducted in the outer solar system," according to Shepard. But as the researchers find more objects, the chances increase that they will be able to definitively determine if something is hiding there.
To improve their chances even more, planetary scientists are eager to get their hands on the Large Synoptic Survey Telescope, LSST, scheduled to begin operating in northern Chile in 2018. It will not be larger than the largest telescopes operating today, but its field of view will be much wider, and therefore it will allow searching in much wider pieces of the sky. Today, says Trujillo, astronomers scan only about 10 square degrees of the sky in search of dim and distant objects - the full moon, by comparison, covers a quarter of a square degree. The LSST "will be able to scan a lot more," he says.
If a super-Earth exists somewhere, and if it's big and bright enough, the LSST should find it. And maybe someone has already seen. In December 2015, for example, observers claimed to have taken direct photographs of a possibly super-Earth object using the Large Millimeter/Submillimeter Array in Atacama, Chile. Most of their colleagues strongly doubt this, but further observations may change this. And maybe, by chance, someone has already photographed our local super-Earth with some other telescope. "Maybe it's waiting on someone's hard drive and nobody noticed it because they weren't looking for it, or they weren't looking for it the right way," says Trujillo. "People tend to see only what they are looking for."
New evidence
[Addition by the author of the article, Michael D. LaMonique, which was published on the Scientific American website on January 20, 2016 following further evidence of the existence of a super-Earth in our solar system. We bring a translated and edited version of the article. – the editors]
In a new analysis of data, accepted for publication in The Astronomical Journal, planetary scientists Konstantin Batigin and Mike Brown of the California Institute of Technology (Caltech) presented what they say is compelling circumstantial evidence for the existence of a previously undiscovered very large, massive planet Perhaps 10 times that of the Earth, orbiting the Sun in the far darkness of the Solar System beyond Pluto. The scientists deduce its existence from deviations in the orbits of some small bodies that can be seen in a telescope. "I haven't been this excited in a long time," says Greg Laflin, an expert on planet formation and dynamics at the University of California, Santa Cruz, who was not involved in the study.
The object, which the researchers call for now the name "Planet Nine," approaches at most a distance of 200 astronomical units from the Sun, or five times the average distance of Pluto. Despite its enormous size, it should be very dim, say the authors of the paper, so it is not surprising that no one has seen it yet.
if it exists at all. "Unfortunately," says Brown, "we have no actual identification." But the evidence is strong enough to attract very careful attention from other experts. "I think it's pretty compelling," says Chad Trujillo of the Gemini Observatory in Hawaii. David Nesburni, a solar system theorist at Southwest Research Institute (SwRI) in Boulder, Colorado, was also very impressed with the results. "These guys are really good," he says. "They have compelling arguments."
[As written in the main article above,] Bettigin and Brown are not the first to speculate that there is another planet in our solar system. Trujillo and Scott Shepherd of the Carnegie Institution for Science proposed their hypothesis based on the high agreement between the perihelion angles of several bodies in the outer solar system. The new analysis dramatically strengthens the hypothesis. It turns out that the similarity in the perihelion angles is "only the tip of the iceberg," says Bettigin.
The first thing he and Brown did, he said, was to analyze Trujillo and Shepherd's data from a completely fresh perspective. "What we've seen," says Bategin, "is that the long elliptical axes of the orbits of these bodies are in the same quadrant of the sky." In other words, they are facing the same direction. This result is not guaranteed. Two bodies can have similar perihelion angles even when in every other sense their orbits are physically different. But when Brown and Tigin charted the orbits of these objects in the outer solar system, they noticed that their elongated elliptical shapes were very closely aligned. "Isn't that something hard to miss?" Brown asks. "Yes indeed. This is a case where our heads were buried in mountains of data. We never took a step back and looked at the solar system from above. I couldn't believe that I had never noticed this before," he says. "It's ridiculous."
The directionality of the orbits served as an even stronger clue that something was physically grouping these distant bodies together. "In the beginning," says Brown, "we said, 'There's no way there's a planet there, it's a crazy idea.'" So they looked at the most likely alternative: that the Kuiper Belt, with all its icy bodies beyond Pluto, arranged itself naturally, much like the galaxies through which Gravity gathered themselves into their shape out of the cosmic gas cloud created by the Big Bang.
The gravity of a putative planet, dubbed Planet Nine, may explain oddities in the orbits of two groups of objects that lie beyond Pluto.
New evidence
The gravity of a putative planet, dubbed Planet Nine, may explain oddities in the orbits of two groups of objects that lie beyond Pluto. (Figure produced using Worldwide Telescope, Caltech/R. Hart (IPAC))
The difficulty in this scenario, the researchers who wrote the article realized, was that the Kuiper Belt does not have enough mass for the scenario to actually materialize. However, when the scientists used the "crazy" idea of a planet, the simulations created exactly the right structure of aligned orbits. They also revealed something else: the gravity of the giant planet is supposed to lead to the creation of a completely separate group of objects, whose orbits are not aligned with each other but are tilted at a sharp angle relative to the orbits of the planets - up to an angle of 90 degrees from the plane of the solar system. "It seems really confusing," says Bettigin. "But then Mike said, 'I think I saw something like that in the data.'" Indeed, observers have already located about six bodies just like this, and no one has offered a good explanation for their unusual orbits. Now, Batygin and Brown's computer simulations have provided an explanation. "The fact that they now have two independent lines of evidence for the existence of a putative planet," Leflin says, "further strengthens their case."
The planet that best fits the data should have a mass on the order of 10 times that of Earth, but less than that of Neptune, the fourth-largest known planet around the Sun, which is about 17 times that of Earth. This mass places it, as mentioned, in the category known as super-Earth, which includes many planets orbiting other suns, but no planet, so far, in our solar system. Its most likely orbit is a very elongated orbit, one that brings it within 35 billion kilometers of the Sun at its closest point ("and that's where it does most of the damage," Brown says) and three to six times greater distance at its farthest point.
And even at this enormous distance, in principle it is possible to observe planet nine using the telescopes that exist today. The most suitable telescope is the Japanese Subro Telescope in Hawaii, which has a huge mirror for capturing faint light and also a wide field of view that will allow researchers to easily scan wide swathes of the sky. "Unfortunately, Sobro is not in our possession," says Brown, "so it is unlikely that we will be the ones to find it. We therefore direct each other where to look."
Until they actually see Planet Nine, astronomers cannot definitively confirm that it is real. "I tend to be very skeptical about claims of another planet in the solar system," says Hal Levinson of the Southwest Research Institute. "I've seen many, many claims like that throughout my career, and they've all been wrong." The fact that the tracks are aligned is real, he admits. "Something is causing it. But we need to investigate a little more what this factor is."
But overall, it is clear that the planetary scientists are agitated by the possibility that we are on the verge of such an important discovery. "When I grew up," Shepard says, "we thought that all the big planets had already been discovered. It can be very exciting and very surprising to find out that we were wrong." The entire astronomical community is captivated, says Laflin, by the charms of what the British astronomer John Herschel delivered before the British Association for the Advancement of Science on September 10, 1846. An irregularity discovered in the orbit of Uranus hinted at the time that the gravity of a heavy and unknown planet was causing it.
This is what Herschel said about the mysterious object: "We see it as Columbus saw America from the shores of Spain. His movements are felt along the entire length of our far-reaching line of inquiry, with a certainty that falls just a little bit out of sight with the eyes." Only two weeks later, Neptune was discovered, exactly where the theorists' calculations predicted it should be.
About the writers
Photo by Michael D. LeMonique
Michael D. LeMonique
Editor of the book "The Earth in the Mirror: The Search for a Twin Planet" (Walker Books, 2012). For 21 years he was a science reporter for Time magazine. He currently serves as the opinion editor for Scientific American.
for further reading
A Sedna-like Body with a Perihelion of 80 Astronomical Units. Chadwick A. Trujillo and Scott S. Sheppard in Nature, Vol. 507, pages 471–474; March 27, 2014
Extreme Trans-Neptunian Objects and the Kozai Mechanism: Signaling the Presence of Trans-Plutonian Planets. C. de la Fuente Marcos and R. de la Fuente Marcos in Monthly Notices of the Royal Astronomical Society Letters, Vol. 443, no. 1; pages L59–L63; September 1, 2014
Strong Evidence Suggests a Super Earth Lies beyond Pluto. Michael D. Lemonick, Scientific American online. January 20, 2016
Pluto and Beyond, Michael D. Lamonique, Scientific American Israel, February-March 2015, pages 30-37
