Astronomy

Was there ever a hypothesis about a planet called Biga?

Was there ever a hypothesis about a planet called Biga?


We are searching data for your request:

Forums and discussions:
Manuals and reference books:
Data from registers:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.

I just re-read a popular astronomy book that was published when I was a child, about 1973. It starts with an interview to Harold C. Urey where the interviewer asks about a hypothetical planet in our solar system called Biga.

Has a hypothetical planet ever been called "Biga" by its proponents, in the same way there was a proposed planet "Vulcan", or is this "Biga" name a printing or translation error?

If it's a mistake and there never was a "Biga" proposal, which is the proposed planet with the most similar name?

This link contains such interview, in Spanish. I will translate and quote its most relevant text:

Interviewer: At present, do we know all the planets of the Solar System, or is there the possibility of still unknown planets in our system?

H.C. Urey: We certainly know the nine usual planets. Recently there has been much talk of another object moving in space and supposed to be close to the Solar System, but I am not sure that it is a real hypothesis, and personally I think it is better to wait before deciding whether it is Not of a planet. I consider it sufficient to say that there are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto and the asteroidal belt.

Interviewer: When talking about this object, are you referring to the so-called planet Biga?

H.C. Urey: Yes, that's what I meant, but I'm not sure of its existence.

Please, remember:

1- This interview mas made about 45 yeras ago.

2- I'm not asking if this hypothesis is correct or even possible. Only want to know more about this hypothesis which was well known by H. C. Urey in the 70's.

3- I'm not asking if the name "Biga" is a correct proposal of a name for a planet in our Solar System accordind to current naming rules.


If another planet in our solar system was to be named, I think that Biga wouldn't be the first name to come up, all of the known planets in our solar system are named after Roman deities and Biga is not a deity but rather a cart on which mostly Luna is depicted. I have never heard of this proposal and if the 'rules' are used for naming, it wouldn't be the first candidate.


This Wikipedia page doesn't say anything about a planet called Biga, and I couldn't find anything on the internet related to Harold Urey, and a possible tenth planet (netheir on Google nor on Wikipedia).

This page says that at that time, there was a theorized planet X, which might be what you are looking for, but lacking any references for Biga on the internet, it is hard to say anything.


Beyond “Fermi’s Paradox” IV: What is the Rare Earth Hypothesis?

Welcome back to our Fermi Paradox series, where we take a look at possible resolutions to Enrico Fermi’s famous question, “Where Is Everybody?” Today, we examine the possibility that planets capable of supporting life are simply too rare.

In 1950, Italian-American physicist Enrico Fermi sat down to lunch with some of his colleagues at the Los Alamos National Laboratory, where he had worked five years prior as part of the Manhattan Project. According to various accounts, the conversation turned to aliens and the recent spate of UFOs. Into this, Fermi issued a statement that would go down in the annals of history: “Where is everybody?

This became the basis of the Fermi Paradox, which refers to the high probability estimates for the existence of extraterrestrial intelligence (ETI) and the apparent lack of evidence. Seventy years later, we still haven’t answered that question, which has led to many theories as to why the “Great Silence” endures. Today, we address another, which is the possibility that life-bearing planets like Earth are just very rare.

This is what is popularly known as the “Rare Earth Hypothesis,” which argues that the emergence of life and the evolution of complexity require a combination of astrophysical and geological conditions that are simply not common in our Universe. This contradicted previously-held notions by prominent scientists and SETI researchers, who were of the opinion that Earth was typical of rocky planets located throughout the Universe.

The “pale blue dot” of Earth captured by Voyager 1 on February 14th, 1990. Credit: NASA/JPL


First: Astronomers capture a planet in the process of forming

Just slightly over a year ago, astronomers announced that they had found and imaged definitive signs of planetary formation, in the form of a banded proto-planetary disc around a distant star. These bands were supposed too be paths swept out of the larger disc by orbiting planets still in the process of formation — but, sensible though that hypothesis is, it was still just a hypothesis. Now, scientists from Stanford and NASA have announced another step forward: they’ve used even more sophisticated imaging techniques to directly observe the planet supposed to be carving out these banded circular regions, and in so doing have finally snapped an image of the final step in the current model of planetary formation.

The study’s authors say that their paper, which focuses on a nascent gas giant about 450 light-years away called LkCa 15 b, is the first incontrovertible observation of a proto-planet — that is, a planet still in the process of forming. LkCa 15 b seems to be a roughly Jupiter-like planet forming around a roughly Sun-like star. That’s exciting all on its own, but the researchers point out that it takes a long time for planets to form, so we can expect this system to provide useful results for a long time. By returning to LkCa 15 b periodically, astronomers should be able to check in on the kinetics of forming planets.

It may be blurry, this is part of the history of astronomy.

Their image was created using hydrogen-alpha photons, which are released when super-heated material joins a forming planet by the process of accretion. Planets are believed to have small discs themselves, while forming, so as material was pulled out of this disc and down into the growing mass, it released a characteristic burst of light. Significant work went into filtering out the blindingly bright light of the host star, and isolating just the radiation of interest. One researcher likened the difference in brightness to that between a lighthouse and a firefly.

An artist rendering of exoplanet phases. Credit: Lisa Esteves

There are actually multiple candidate planets in this same system, presumably hiding in other band within the disc, and these proto-planets have been detected by preliminary means, but not yet imaged. If they can image multiple forming planets, especially over multiple star systems, astronomers might be able to establish a relationship between a band region around a star and certain characteristics of the planet forming within it if scientists can learn about one from the other, then they might be able to do much quicker, easier searches for forming planets by looking for the much more visible disc of debris that contain them.

Looking into the earliest stages of planetary development should shed light on just how our own solar system formed, and why it currently is the way that it is. Not only is the planet still forming, but the star it orbits is only 20 million years old — still a baby, itself. Though they won’t be able to watch long enough to see this system actually evolve over time, the hope is to someday find systems that can stand in as more static snapshots of the process at various stages.

It’s not currently known just how long it takes to form planets after the star’s initial formation, so it’s not known how many planet-forming systems we should expect to find in the universe. There are still lot of unknowns — but one fewer than there was before, which is all you can ever really ask.


The Moon formed elsewhere and was captured by Earth's gravity.

Hypothesis for Moon formation

While advocates of this model differ in their proposed origin of the interloper, the fact that the age of the Moon is similar to the solar system makes it likely that the source of the material is from within the solar system. Dalrymple points out that the oxygen isotope concentration is identical in the Earth and Moon and the undifferentiated meteorites, but different from that in more primitive meteorites. This would seem to restrict the source of the Moon to the same general neighborhood of the solar system as the Earth, but the bulk composition of the Earth with its large iron core is greatly different from that of the Moon.

Can the Earth just capture a neighbor that wanders by and make a moon of it? Not without losing a lot of energy! A smaller body that encounters the gravity of a larger body will experience the slingshot effect, more formally known as a gravity assist maneuver, and will escape the encounter traveling in another direction.

Alternative hypotheses for Moon formation
Index


Theory

A scientific theory summarizes a hypothesis or group of hypotheses that have been supported with repeated testing. A theory is valid as long as there is no evidence to dispute it. Therefore, theories can be disproven. Basically, if evidence accumulates to support a hypothesis, then the hypothesis can become accepted as a good explanation of a phenomenon. One definition of a theory is to say that it's an accepted hypothesis.

Example: It is known that on June 30, 1908, in Tunguska, Siberia, there was an explosion equivalent to the detonation of about 15 million tons of TNT. Many hypotheses have been proposed for what caused the explosion. It was theorized that the explosion was caused by a natural extraterrestrial phenomenon, and was not caused by man. Is this theory a fact? No. The event is a recorded fact. Is this theory, generally accepted to be true, based on evidence to-date? Yes. Can this theory be shown to be false and be discarded? Yes.

A scientific law generalizes a body of observations. At the time it's made, no exceptions have been found to a law. Scientific laws explain things but they do not describe them. One way to tell a law and a theory apart is to ask if the description gives you the means to explain "why." The word "law" is used less and less in science, as many laws are only true under limited circumstances.

Example: Consider Newton's Law of Gravity. Newton could use this law to predict the behavior of a dropped object but he couldn't explain why it happened.

As you can see, there is no "proof" or absolute "truth" in science. The closest we get are facts, which are indisputable observations. Note, however, if you define proof as arriving at a logical conclusion, based on the evidence, then there is "proof" in science. Some work under the definition that to prove something implies it can never be wrong, which is different. If you're asked to define the terms hypothesis, theory, and law, keep in mind the definitions of proof and of these words can vary slightly depending on the scientific discipline. What's important is to realize they don't all mean the same thing and cannot be used interchangeably.


Was there ever a hypothesis about a planet called Biga? - Astronomy

SpaceTime with Stuart Gary Series 24 Episode 41

*Could there be parts of another planet inside the Earth?

A new hypothesis claims large parts of the planet Theia may still be present buried deep in the Earth’s mantle.

*The anatomy of a Nova explosion

Astronomers have gathered their best ever observations of a spectacular stellar explosion called a nova.

*China gears up for war launching another spy satellite

China is continuing its military build-up with the launch of another spy satellite.

*The Science Report

A new study suggests that older people have a greater risk of getting COVID-19 twice.

Antarctica’s Pine Island Glacier could cross tipping points with consequences for global sea levels.

Why people with red hair have a different pain threshold.

Archaeologists describe a stunning collection of Arnhem Land rock art images.

Alex on Tech looks at Facebooks sloppy security with your personal details.

Your support is needed.

SpaceTime is an independently produced podcast (we are not funded by any government grants, big organisations or companies), and we’re working towards becoming a completely listener supported show. meaning we can do away with the commercials and sponsors. We figure the time can be much better spent on researching and producing stories for you, rather than having to chase sponsors to help us pay the bills.

That's where you come in. help us reach our first 1,000 subscribers. at that level the show becomes financially viable and bills can be paid without us breaking into a sweat every month. Every little bit helps. even if you could contribute just $1 per month. It all adds up.


Neptune's twin

The prediction: This month, noted astronomer Rodney Gomes of the National Observatory of Brazil in Rio de Janeiro released new computer models suggesting there may be a Neptune-size planet at the outskirts of the solar system. His models show that this planet could explain the mysterious, highly elongated orbits of certain objects in the "scattered disc," a collection of icy bodies beyond Neptune, including that of the dwarf planet Sedna. Gomes says the existence of an unseen planet is the simplest way to account for these objects' motions.


Mystery orbits in outermost reaches of solar system not caused by 'Planet Nine'

Kuiper Belt's ice cores. Credit: ESO/M. Kornmesser

The strange orbits of some objects in the farthest reaches of our solar system, hypothesised by some astronomers to be shaped by an unknown ninth planet, can instead be explained by the combined gravitational force of small objects orbiting the Sun beyond Neptune, say researchers.

The alternative explanation to the so-called 'Planet Nine' hypothesis, put forward by researchers at the University of Cambridge and the American University of Beirut, proposes a disc made up of small icy bodies with a combined mass as much as ten times that of Earth. When combined with a simplified model of the solar system, the gravitational forces of the hypothesised disc can account for the unusual orbital architecture exhibited by some objects at the outer reaches of the solar system.

While the new theory is not the first to propose that the gravitational forces of a massive disc made of small objects could avoid the need for a ninth planet, it is the first such theory which is able to explain the significant features of the observed orbits while accounting for the mass and gravity of the other eight planets in our solar system. The results are reported in the Astronomical Journal.

Beyond the orbit of Neptune lies the Kuiper Belt, which is made up of small bodies left over from the formation of the solar system. Neptune and the other giant planets gravitationally influence the objects in the Kuiper Belt and beyond, collectively known as trans-Neptunian Objects (TNOs), which encircle the Sun on nearly-circular paths from almost all directions.

However, astronomers have discovered some mysterious outliers. Since 2003, around 30 TNOs on highly elliptical orbits have been spotted: they stand out from the rest of the TNOs by sharing, on average, the same spatial orientation. This type of clustering cannot be explained by our existing eight-planet solar system architecture and has led to some astronomers hypothesising that the unusual orbits could be influenced by the existence of an as-yet-unknown ninth planet.

The 'Planet Nine' hypothesis suggests that to account for the unusual orbits of these TNOs, there would have to be another planet, believed to be about ten times more massive than Earth, lurking in the distant reaches of the solar system and 'shepherding' the TNOs in the same direction through the combined effect of its gravity and that of the rest of the solar system.

"The Planet Nine hypothesis is a fascinating one, but if the hypothesised ninth planet exists, it has so far avoided detection," said co-author Antranik Sefilian, a Ph.D. student in Cambridge's Department of Applied Mathematics and Theoretical Physics. "We wanted to see whether there could be another, less dramatic and perhaps more natural, cause for the unusual orbits we see in some TNOs. We thought, rather than allowing for a ninth planet, and then worry about its formation and unusual orbit, why not simply account for the gravity of small objects constituting a disc beyond the orbit of Neptune and see what it does for us?"

Professor Jihad Touma, from the American University of Beirut, and his former student Sefilian modelled the full spatial dynamics of TNOs with the combined action of the giant outer planets and a massive, extended disc beyond Neptune. The duo's calculations, which grew out of a seminar at the American University of Beirut, revealed that such a model can explain the perplexing spatially clustered orbits of some TNOs. In the process, they were able to identify ranges in the disc's mass, its 'roundness' (or eccentricity), and forced gradual shifts in its orientations (or precession rate), which faithfully reproduced the outlier TNO orbits.

"If you remove planet nine from the model and instead allow for lots of small objects scattered across a wide area, collective attractions between those objects could just as easily account for the eccentric orbits we see in some TNOs," said Sefilian, who is a Gates Cambridge Scholar and a member of Darwin College.

Earlier attempts to estimate the total mass of objects beyond Neptune have only added up to around one-tenth the mass of the Earth. However, in order for the TNOs to have the observed orbits and for there to be no Planet Nine, the model put forward by Sefilian and Touma requires the combined mass of the Kuiper Belt to be between a few to ten times the mass of the Earth.

"When observing other systems, we often study the disc surrounding the host star to infer the properties of any planets in orbit around it," said Sefilian. "The problem is when you're observing the disc from inside the system, it's almost impossible to see the whole thing at once. While we don't have direct observational evidence for the disc, neither do we have it for Planet Nine, which is why we're investigating other possibilities. Nevertheless, it is interesting to note that observations of Kuiper belt analogues around other stars, as well as planet formation models, reveal massive remnant populations of debris.

"It's also possible that both things could be true—there could be a massive disc and a ninth planet. With the discovery of each new TNO, we gather more evidence that might help explain their behaviour."


The Final Word? –“Alien-Hypothesis ‘Oumuamua’ is a Fragment of a Pluto-like Planet from Another Solar System”

It might be a good time for the Oxford University Union to schedule a debate between two Arizona State astronomers and Harvard’s intrepid Avi Loeb , author of the recently published Extraterrestrial: The First Sign of Intelligent Life Beyond Earth . “Extraterrestrial,” writes the New York Times Dennis Overbye …”is part graceful memoir and part plea for keeping an open mind about the possibilities of what is out there in the universe — in particular, life. Otherwise, Loeb says, we might miss something amazing, like the church officials in the 17th century who refused to look through Galileo’s telescope.”

“No More Speculative than Extra Dimensions or Dark Matter?”

“The idea of the existence of advanced extraterrestrial life is no more speculative than extra dimensions or dark matter. In fact, it is less so,” said Loeb. In November of 2018, The Daily Galaxy reported in “Sent By an Alien World?”: “You would have thought it was 1938 again following Orson Welles’ radio broadcast of the War of the Worlds the way Twitter lit up when the chairman of Harvard’s astronomy department, Israel-born theoretical physicist Avi Loeb, then the chair of Harvard’s astronomy department, co-wrote a paper that examined the ‘ peculiar acceleration’ of the strange disk-like object that entered our Solar System suggesting that it is an alien spaceship may be a fully operational probe sent intentionally to Earth’s vicinity by an alien civilization, and probably had Stephen Hawking spinning in his grave.”

“When it was discovered,” Loeb told Isaac Chotiner for The New Yorker ., “we realized it spins every eight hours, and its brightness changed by at least a factor of ten. The fact that its brightness varies by a factor of ten as it spins means that it is at least ten times longer than it is wide. We don’t have a photo, but, in all the artists’ illustrations that you have seen on the Web, it looks like a cigar. That’s one possibility. But it’s also possible that it’s a pancake-like geometry, and, in fact, that is favored.”

Fast Forward to “The Debate”

“In many ways ‘Oumuamua resembled a comet, but it was peculiar enough in several ways that mystery surrounded its nature, and speculation ran rampant about what it was,” said Steven Desch , a professor in the School of Earth and Space Exploration at Arizona State University, about the first interstellar object from beyond our solar system was discovered in 2017 via the Pan-STARRS astronomical observatory in Hawaii. The object, named ‘Oumuamua, meaning “scout” or “messenger” in Hawaiian, was like a comet, but with features that were strange enough to defy classification.

The two Arizona State University astrophysicists, Desch and Alan Jackson of the School of Earth and Space Exploration, set out to explain the odd features of ‘Oumuamua and have determined that it is likely a piece of a Pluto-like planet from another solar system. Their findings have been recently published in a pair of papers in the AGU Journal of Geophysical Research: Planets.

From observations of the object, Desch and Jackson determined several characteristics of the object that differed from what would be expected from a comet.

First. ..In terms of speed, the object entered the solar system at a velocity a bit lower than would be expected, indicating that it had not been traveling in interstellar space for more than a billion years or so. In terms of size, its pancake shape was also more flattened than any other known solar system object.

Second … they observed that while the object acquired a slight push away from the sun (a “rocket effect” common in comets as sunlight vaporizes the ices they are made of), the push was stronger than could be accounted for.

Third … the object lacked a detectable escaping gas, out-gassing, which is usually depicted visibly by a comet’s tail. In all, the object was very much like a comet, but unlike any comet that had ever been observed in the solar system.

Desch and Jackson then hypothesized that the object was made of different ices and they calculated how quickly these ices would sublimate (passing from a solid to a gas) as ‘Oumuamua passed by the sun. From there, they calculated the rocket effect, the object’s mass and shape, and the reflectivity of the ices.

“That was an exciting moment for us,” Desch said. “We realized that a chunk of ice would be much more reflective than people were assuming, which meant it could be smaller. The same rocket effect would then give ‘Oumuamua a bigger push, bigger than comets usually experience.”

Frozen Nitrogen–The Link We Observe on the Surface of Pluto or Triton

Desch and Jackson found one ice in particular—solid nitrogen—that provided an exact match to all the object’s features simultaneously. And since solid nitrogen ice can be seen on the surface of Pluto, it is possible that a comet-like object could be made of the same material.

“We knew we had hit on the right idea when we completed the calculation for what albedo (how reflective the body is) would make the motion of ‘Oumuamua match the observations,” said Jackson, who is a research scientist and an Exploration Fellow at ASU. “That value came out as being the same as we observe on the surface of Pluto or Triton, bodies covered in nitrogen ice.”

They then calculated the rate at which chunks of solid nitrogen ice would have been knocked off the surfaces of Pluto and similar bodies early in our solar system’s history. And they calculated the probability that chunks of solid nitrogen ice from other solar systems would reach ours.

“It was likely knocked off the surface by an impact about half a billion years ago and thrown out of its parent system,” Jackson said. “Being made of frozen nitrogen also explains the unusual shape of ‘Oumuamua. As the outer layers of nitrogen ice evaporated, the shape of the body would have become progressively more flattened, just like a bar of soap does as the outer layers get rubbed off through use.”

Could It Have Been Alien Technology?

Although ‘Oumuamua’s cometlike nature was quickly recognized, the inability to immediately explain it in detail led to speculation that it is a piece of alien technology, as in Loeb’s recently published book “Extraterrestrial: The First Signs of Intelligent Life Beyond Earth” by Avi Loeb of Harvard University.

Illustration of a plausible history for ‘Oumuamua: Origin in its parent system around 0.4 billion years ago erosion by cosmic rays during its journey to the solar system and passage through the solar system, including its closest approach to the Sun on Sept. 9, 2017, and its discovery on October 2017. At each point along its history, this illustration shows the predicted size of ‘Oumuamua, and the ratio between its longest and shortest dimensions. Credit: S. Selkirk/ASU

This has sparked a public debate about the scientific method and the responsibility of scientists not to jump to unwarranted conclusions.

“Everybody is interested in aliens, and it was inevitable that this first object outside the solar system would make people think of aliens,” Desch said. “But it’s important in science not to jump to conclusions. It took two or three years to figure out a natural explanation—a chunk of nitrogen ice—that matches everything we know about ‘Oumuamua. That’s not that long in science, and far too soon to say we had exhausted all natural explanations.”

Although there is no evidence that it is alien technology, as a fragment of a Pluto-like planet, ‘Oumuamua has provided scientists with a special opportunity to look at extrasolar systems in a way that they have not been able to before. As more objects like ‘Oumuamua are found and studied, scientists can continue to expand our understanding of what other planetary systems are like and the ways in which they are similar to, or different from, our own solar system.

“This research is exciting in that we’ve probably resolved the mystery of what ‘Oumuamua is and we can reasonably identify it as a chunk of an ‘exo-Pluto,’ a Pluto-like planet in another solar system,” Desch said. “Until now, we’ve had no way to know if other solar systems have Pluto-like planets, but now we have seen a chunk of one pass by Earth.”

The First of Many to Follow?

Desch and Jackson hope that future telescopes, like those at the Vera Rubin Observatory/Large Synoptic Survey Telescope in Chile, which will be able to survey the entire southern sky on a regular basis, will be able to start finding even more interstellar objects that they and other scientists can use to further test their ideas.

“It’s hoped that in a decade or so we can acquire statistics on what sorts of objects pass through the solar system, and if nitrogen ice chunks are rare or as common as we’ve calculated,” Jackson said. “Either way, we should be able to learn a lot about other solar systems, and whether they underwent the same sorts of collisional histories that ours did.”

Source: Alan P. Jackson et al. 1I/’Oumuamua as an N 2 ice fragment of an exo‐Pluto surface: I. Size and Compositional Constraints , Journal of Geophysical Research: Planets (2021). DOI: 10.1029/2020JE0067

Editor’s Note: Interestingly, today’s article exemplifies the scientific process, which often includes continuous debate and attempts to explain evidence in different ways. These debates can sometimes be fierce and long lived, although are usually far away from the public eye. But when words like “life” and/or “aliens” are included, the attention from the public and the media makes the stakes higher. (Avi Shporer)

The Daily Galaxy with Avi Shporer, Research Scientist, MIT Kavli Institute for Astrophysics and Space Research, via Arizona State University and Avi Loeb, Extraterrestrial (Kindle Edition). Avi was formerly a NASA Sagan Fellow at the Jet Propulsion Laboratory (JPL)


This Is Why Most Scientists Think Planet Nine Doesn't Exist

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.

Wikimedia Commons users Tomruen, nagualdesign

It's been nearly three years since one of the most exciting proposals concerning our own cosmic backyard came out: far out beyond Neptune, there might be another planet — even more massive than Earth — in our Solar System. Unlike the tiny worlds previously discovered in the Kuiper belt, like Pluto and Eris, this would be a world that was Super-Earth sized, at perhaps ten times the Earth's mass, responsible for kicking bizarrely-orbiting objects into our view.

As Konstantin Batygin and Mike Brown proposed, there would be additional pieces of evidence one would expect, and some of them started to come in. But most scientists disagree that this is good evidence at all. Instead, they contend, the data is biased. When you account for that bias, there's no need for Planet Nine at all.

The alignment in ecliptic latitude and longitude of many of the longest-period Trans-Neptunian . [+] Objects could have been a coincidence, a result of biased surveys, or an indicator of a new physical phenomenon.

K. Batygin and M. E. Brown Astronom. J. 151, 22 (2016)

The Kuiper belt is home to the largest number of distant objects we've ever discovered. If you look out at them, you'd expect their orbits to have relatively random orientations, where their tilts and their points-of-closest-approach should be equally likely to occur in all directions.

Yet the most distant ones, according to the full suite of observations available, showed orbits that were swept off in one particular direction and tilted in the same direction. If you only had one or two objects doing this, you might chalk it up to random chance, but we had six the odds that this would be random was around 0.0001%. Instead, astronomers Konstantin Batygin and Mike Brown proposed a radical new theory: that there was an ultra-distant ninth planet — more massive than Earth but smaller than Uranus/Neptune — knocking these objects into their new orbits.

The orbits of the known Sednoids, along with the proposed Planet Nine. In the far future, Planet . [+] Nine — whose existence is very controversial to begin with — will not reach sufficient temperatures to become potentially habitable even when the Sun becomes a red giant star.

K. Batygin and M. E. Brown Astronom. J. 151, 22 (2016), with modifications/additions by E. Siegel

This fascinating idea, if true, would come along with a few interesting consequences. In particular, it ought to leave the following specific signatures:

  • It should produce an excess population of objects that get stretched into long-period orbits from gravitational interactions,
  • Those objects have their orbits and their orbital planes tilted in a particular fashion, due to the influence of Planet Nine,
  • There should be a small, but non-zero population of objects with orbits exactly opposite to the excess population,
  • And Planet Nine, itself, should be out there, waiting to be found.

Batygin & Brown, as additional studies have come in, have been pointing to a few different objects — one here, one there, another two in a follow-up study — as evidence of those first three points. But Planet Nine itself has still eluded direct detection.

The unusually closely spaced orbits of six of the most distant objects in the Kuiper Belt, as . [+] originally identified in 2016, may indicate the existence of a ninth planet whose gravity affects these movements.

Wikimedia user nagualdesign via Caltech

That's not entirely a surprise! Even if Planet Nine were real and large, it would be incredibly faint at its predicted distance from the Sun. You might think that if it were ten times as distant as Uranus and nearly the same size, it should be only 100 times fainter, since brightness falls off as one over the distance squared. But sunlight suffers that problem twice from our perspective: the sunlight reaching such a distant world would be 100 times fainter than the sunlight reaching a closer world, but then that light gets reflected, and has to travel ten times as far before it arrives back at Earth. Instead of falling off as 1/r 2 , the light we effectively see falls off as 1/r 4 , making any world that distant incredibly difficult to see.

Very faint objects can be detected with dedicated astronomical surveys, but finding a small, faint, . [+] distant object in our Solar System is made even harder by the 'reflected sunlight' problem. For an object twice as distant as another, the light first has to go out twice as far, meaning just 1/4th as much reaches it, and then come back twice as far as well, leading to 1/16th the original brightness. The 1/r^4 relation for brightness-distance in this case is catastrophic.

It's worth mentioning, from a theoretical perspective, that this is a brilliant idea. Anytime you can take a slew of observations that don't seem to make sense on their own and explain what caused them with a single new object, it's very compelling. But like many brilliant ideas, it's also possible that it's simply wrong. Seeing six ultra-distant objects doing something slightly unusual doesn't mean there aren't also six million ultra-distant objects doing something perfectly normal, but those aren't the ones we've seen yet.

In short, we have to make sure that the evidence we're seeing is representative of the objects that are out there, and that's where this idea runs into trouble.

This compressed view of the entire sky visible from Hawai'i by the Pan-STARRS1 Observatory is the . [+] result of half a million exposures, each about 45 seconds in length. But the surveys that the Planet Nine data was pulled from are not this even on the sky.

Danny Farrow, Pan-STARRS1 Science Consortium and Max Planck Institute for Extraterrestrial Physics

So far, all we've had to rely on is the indirect evidence that Batygin and Brown have put forth. They've claimed a total, so far, of ten such objects that match their predictions. That's impressive, and represents an improvement over the original six that were claimed initially.

But they weren't using data from an all-sky survey to find these objects those surveys (like Pan-STARRS) don't go deep enough. The trans-Neptunian objects, and their peculiar orbits that the hypothetical Planet Nine would be responsible for, ought to be located in a particular region of the sky. And so if you want to find these objects, there are particular locations you'd look in order to see them.

The orbit of 2015 RR245, compared with the gas giants and the other known Kuiper Belt Objects. Note . [+] the fact that, as Earth orbits the Sun, it is subject to seasons, weather, and which parts of the skies are visible. This could lead to a tremendous bias in what we do-and-don't detect.

Alex Parker and the OSSOS team

That's fine, but the whole motivation that Batygin and Brown's theory relies on isn't that "these objects exist," but rather that "these objects exist and their clustering is very unlikely to happen just by chance."

But how likely is that clustering? It relies heavily on a couple of factors, like where you've observed and with what sensitivity you've made those observations. If you spend more of your observing time looking in locations where you expect you'll find clustered objects, of course you'll find more you've spend more time observing there and will find more things in general. That doesn't mean there's anything unusual happening, like additional clustering.

In fact, it's more likely, if that's the case, that there isn't anything unusual it's more likely that you're the victim of a phenomenon called detection bias.

Finding ultra-faint, ultra-cool, or slowly-moving objects is possible with current, existing . [+] technology, but is entirely dependent on looking in the locations where these objects exist for long enough. Here, the WISE mission finds a rare, ultra-cool dwarf star, shown in red. This may not be the best way to look for Planet Nine.

Those ten objects that Batygin and Brown identified came from a variety of surveys with a variety of depths, and importantly, the effect of detection bias was never quantified or adequately addressed. To visualize this, imagine you've got a telescope situated near the equator on Earth, and you spend every night looking out at the night sky, trying to view as much of it as possible as deeply as possible. If you had clear, dark skies, with good seeing, for 365 days out of the year, then you'd be able to get all portions of the sky equally. But you don't. Instead:

  • Some parts of the year are more prone to foul weather,
  • Some parts of the year are more likely to have turbulent air and poor atmospheric seeing conditions,
  • Some parts of the sky, like the galactic plane, are too contaminated to reliably locate TNOs,

and so on. The point is, if you preferentially observe the two particular regions of sky where you expect objects to be clustered, you're going to find clustered objects there. And it might simply be you're finding them because that's where you're looking.

The 3D orbits of the Kuiper belt objects influenced by Planet Nine. As Mike Brown said, 'The distant . [+] objects with orbits perpendicular to the solar system were predicted by the Planet Nine hypothesis. And then found 5 minutes later.' But it could have only been discovered because of where the good data exists.

Mike Brown / http://www.findplanetnine.com/

Sure, Batygin and Brown's team have identified 10 such objects so far, and they do show that clustering. But does that point towards evidence for Planet Nine?

There's a straightforward way to test whether the effect is real: do a dedicated survey that doesn't have this bias, or at least, quantifies this bias. There's a big survey going on to hunt for worlds beyond Neptune in our Solar System: OSSOS, the Outer Solar System Origins Survey. It found over 800 objects during its duration, looking at eight different well-defined patches of sky over a four year timespan. (It takes that long to find appreciable movement, and measure the orbital parameters, when it comes to worlds so distant from our Sun!) And of these hundreds of objects, eight of them have the long-period properties that would show evidence for-or-against Planet Nine.

Of the long-period Trans-Neptunian objects identified in the OSSOS study, only one of them (shown in . [+] blue) has the parameters that would be consistent with the Batygin & Brown theory of Planet Nine.

Mike Brown / http://www.findplanetnine.com/

The results are definitive. and damning. Independently, prior to this study, simulations were performed with-and-without a massive ninth planet beyond Neptune, indicating what results would favor a ninth planet's existence, and what would disfavor it. For the eight such objects that were found, here's what the survey results indicated:

  • The eight OSSOS discoveries have orbits oriented across a wide range of angles.
  • The observed orbits are statistically consistent with random.
  • The OSSOS detections do not all follow the pattern seen in the previous sample.
  • One of them sits at right angles to the proposed two clusters.
  • The orbits are not tightly clustered.

In theory, Planet Nine would likely be similar to the exoplanet 55 Cancri e, which is approximately . [+] twice the Earth's radius, but eight times the Earth's mass. This new study, however, disfavors the existence of such a world in our outer Solar System entirely.

Most importantly, what they found was entirely consistent with no Planet Nine, and that the overall case for Planet Nine's existence was substantially weakened by their study. In particular, the clustering in the orientation of each orbit in space (defined by multiple variables, ω and Ω) that earlier studies, like Batygin & Brown and Trujillo & Sheppard, previously noticed simply doesn't exist in this new, unbiased study.

We find no evidence in the OSSOS sample for the ω clustering that was the impetus for the current additional planet hypothesis.

Four of the Trans-Neptunian Objects found by OSSOS, shown along with Neptune's orbit for comparison. . [+] The OSSOS objects do not exhibit the same correlations as the prior ones identified by the Planet Nine team.

C. Shankman et al., arXiv:1706.05348v2

The authors of this 2017 study suggest that, in fact, detection bias is the reason why prior research seemed to favor the existence of such a world. However, careful determination of observational biases — newly identified in the OSSOS study — explain why those prior correlations appeared, and why they fail to appear in the new data.

We suggest that this clustering is the result of a combination of observing bias and small number statistics, though we cannot test this without published characterizations of the surveys that detected these TNOs.

Distribution of Scattered Disk objects, with an additional object, 2015 RR245, added in by hand. . [+] Until we have a deeper, unbiased survey of a large suite of Kuiper belt objects, we may be inevitably drawing biased conclusions concerning what lies beyond our present observational limits.

Wikimedia Commons user Eurocommuter

Of course, this study isn't enough to rule out Planet Nine it still could be out there. As a counterpoint, Mike Brown has contended that a different survey strategy could have been definitive, and OSSOS simply isn't a good survey for indicating yea or nay on Planet Nine. But remember, the old saying goes, "where there's smoke, there's fire," indicating that if you observe an effect, it likely has a cause.

If you all of a sudden discover that what you thought was smoke was a figment of your imagination, it doesn't mean there wasn't a fire, but it sure does make the hypothesis that there ever was a fire a lot less compelling. The OSSOS study doesn't rule out Planet Nine, but it does cast doubt on the idea that the Solar System needs one. Unless a deeper, better survey indicates otherwise, or Planet Nine serendipitously turns up, the default position should be its non-existence.