Tag Archives: ‘alien

Harvard Astronomer Still Believes Interstellar Object Was Alien Technology

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An eminent Harvard astronomer is still spending a lot of his time thinking about our first alien encounter in 2017. That’s when a mysterious object known as ‘Oumuamua passed through the solar system. Scientists have classified ‘Oumuamua variously as an asteroid or a comet, but Avi Loeb, the chair of Harvard’s Department of Astronomy, believes it was really alien — a piece of alien technology we mistook for a naturally occurring space rock. 

Astronomers detected ‘Oumuamua in late 2017 as it glided through the solar system. Its speed and trajectory showed incontrovertibly that it came from outside the solar system, but what was it? It didn’t have a coma or “tail” like a comet, but scientists eventually detected a small force nudging ‘Oumuamua away from the sun. We chalked this up to the release of gas from what was probably a very old comet. But was it? According to Loeb, who works as chair of astronomy at Harvard, ‘Oumuamua had too many bizarre properties to be natural. Be believes ‘Oumuamua is truly alien, and we need to take this possibility seriously if we’re going to get a proper look at the next one. 

Loeb is set to release a book called Extraterrestrial in the coming weeks that lays out his hypothesis, which does include some compelling arguments. ‘Oumuamua remained undetected until it was already on its way out of the solar system. So, there was no way to intercept or capture high-resolution photographs of the object. However, we know it’s not a typical space rock. Our best estimates say ‘Oumuamua is cigar-shaped and about 100 meters long. As Loeb points out, we’ve never seen a natural object that looks like that. ‘Oumuamua is also highly reflective — about 10 times more so than typical asteroids or comets. That could mean its surface is composed of shiny metal. 

‘Oumuamua’s path through the solar system in 2017.

What Loeb finds most convincing is the aforementioned force pushing ‘Oumuamua away from the sun. He contends that the out-gassing theory doesn’t sufficiently explain the facts; any jet of evaporating material powerful enough to move ‘Oumuamua should have been visible from Earth. Because we didn’t see ‘Oumuamua until so late in its transit of the solar system, it’s possible we could be wrong about the shape, too. Loeb theorizes ‘Oumuamua could be a disk less than a millimeter thick. Loeb thinks it’s possible ‘Oumuamua was, in fact, some sort of solar sail device that accelerated because of its proximity to the sun. 

It’s a fascinating idea, but we’ll probably never know if Loeb is right. ‘Oumuamua is already on its way out of the solar system, and we have no way to catch up. Instead, Loeb wants to encourage scientists to take the possibility seriously and keep an eye out for similar objects so we can gather more data. Astronomers spotted one more alien object after ‘Oumuamua, a comet known as 2I/Borisov. There’s no uncertainty about Borisov’s natural origins, which makes ‘Oumuamua seem that much weirder.

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There Are 1,004 Nearby Stars Where an Alien Astronomer Could Detect Life on Earth

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We are in the very early stages of exploring the universe, and our efforts have uncovered thousands of exoplanets. We don’t yet know if any of them support life, but maybe one day we’ll know. In the meantime, Earth is the only planet we know for certain does host life. Researchers from Cornell University and Lehigh University turned this question around. We know Earth has life, but does anyone else? The new study says that, yes, there are 1,004 nearby stars where an alien looking at Earth could potentially know we’re here. 

There are more than 4,000 known exoplanets currently, and most of them were identified with the Kepler Space Telescope. We can’t just point any old telescope at a star and say, “Yep, there’s a planet there.” Stars are so much brighter by comparison that we can’t make out individual worlds. The most common way to spot exoplanets, and the method Kepler used, is to watch for the planet to transit in front of the star. When you hear about a new exoplanet discovery, that’s usually how astronomers found it. 

Here’s the catch: we can only see transits if the plane of an alien solar system is aligned with ours. Otherwise, the planet doesn’t pass in front of the star from our perspective. Professors Lisa Kaltenegger and Joshua Pepper looked at this from the other side — which solar systems would be able to make a transit observation of Earth and detect life-associated molecules in our atmosphere? 

Using NASA’s Transiting Exoplanet Survey Satellite (TESS) star catalog, the pair looked 300 light-years in all directions to find candidate solar systems, ruling out stellar remnants like white dwarfs that cannot (as far as we know) host alien life. There are a huge number of main-sequence stars in this region of space, but only a fraction of them would be able to see Earth passing in front of the sun from where they are. 

The final count, according to Pepper and Kaltenegger, is 1,004. Of those, 508 have angles that would give them at least 10 hours of observational data every time Earth transited the sun. However, 5 percent of the total are stars too young to have developed planets or life. The rest, though, could hypothetically have habitable planets, and two of them have known exoplanets.

In every one of those solar systems, beings like us with an understanding of planetary transits could be seeing Earth darken the sun every year. They might be able to estimate Earth’s size and distance from the sun, and that would indicate the possibility of liquid water on the surface. If they’re a little more advanced than us, they might already have the equivalent of the James Webb Space Telescope, which NASA hopes to launch in the next few years after numerous delays. An instrument such as that could detect the presence of water vapor, methane, phosphine, and other compounds that suggest life. Maybe an alien astronomer is, right at this moment, having a eureka moment as they realize someone is looking back at them from Earth. You should wave hello to be polite just in case.

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Some Asteroids May Be Fragments of a Long-Lost Alien Solar System

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A new paper suggests that there may be 19 asteroids — all part of the Centaur family — that didn’t come from our own solar system at all. If this were proven true, it would mean we have ancient material formed around an alien star in orbit in our own solar system.

Centaurs are some of the most interesting space rocks in our solar system. A Centaur is formally defined as a small body that orbits between Jupiter and Neptune, and that crosses the orbit of at least one giant planet. They sit outside the range of the Jupiter trojans but are much closer to the sun than either the scattered disc or Kuiper Belt. The fact that they cross the orbit of at least one giant planet means that Centaurs do not have stable orbits beyond a time scale of a few million years.

Centaur orbits, as compared to the outer planets, Kuiper Belt objects, and the scattered disc. Image by Wikipedia, CC BY-SA 3.0

Centaurs are called such because they demonstrate the characteristics of both asteroids and comets. The first Centaur discovered, 2060 Chiron, was found in 1977. Initially, it brightened by 75 percent and developed a cometary coma, with a tail detected in 1993. But Chiron is approximately 220km in diameter, much larger than a typical comet nucleus, and it may have a ring system — something never observed around a comet. What do you call a half-comet, half-asteroid? A comeroid Centaur, obviously.

The fact that a Centaur’s orbit around the sun isn’t stable is one of their defining characteristics, which is where this new paper comes in. According to the researchers, there are 19 Centaurs whose orbits and inclination within our solar system can only be explained if they did not originate here at all. Objects in unstable orbits around the sun follow one of three outcomes: They assume stable orbits around either a planet or our sun, they fall into the gravity well of either a planet or the sun, or they are ejected back into the interstellar medium.

Prior to this study, only one potential extra-solar Centaur had been identified, 514107 Kaʻepaokaʻawela. The idea that there might be 19 such objects out of a total population of between 44,000 – >10M is not crazy, nor is the idea that our solar system might have captured such asteroids in the relatively recent past. We have recently detected two comets with an interstellar origin — comet Borisov and the cigar-shaped ‘Oumuamua.

The authors, Namouni and Morais, analyzed the orbits of Centaurs with particularly tilted orbits relative to the plane of the ecliptic (the plane in which the major planets and asteroids all move). They found 19 objects whose orbits cannot be explained if they began life as objects that formed within our solar system. If they’re captured space rocks, on the other hand, their orbits are perfectly explainable. It is not clear that all 19 objects are from the same ejection event, either.

Namouni and Morais do not claim that their gravitational interaction simulation proves that Centaurs are extrasolar captures. But if they are, it would mean there are pieces of another solar system caught within our own. Such material might date back to the Sun’s formation (if it was captured near the beginning of our solar system) or it could have been captured within the past few million years. The dinosaurs, for all their many accomplishments, were absolutely terrible at leaving astronomical records.

Again, there’s precedent for this kind of theory. We have already located two “stellar siblings” of Sol — HD 162826 (110 LY distant, F8V star, 4.5B years old) and HD 186302 (184 LY distant, G2V star, 4.57B years old). Our sun is a G2V star thought to have ignited some 4.6B years ago. It’s clear that there was a great deal of exchange going on at that point in time; the protoplanetary disk of the solar system was clearly seeded with heavy metals by a supernova that went off nearby while our planets were just forming. The explosion wasn’t close enough to scatter our disc, but it left a telltale signature we can still pick up.

The coolest thing about these findings is that it means we could gather information from asteroids that didn’t originate here. It doesn’t really matter if they represent a 4.5B-year-old capture from a long-lost stellar sibling or if these Centaurs are random space rocks like Borisov or ‘Oumuamua. No matter where they came from or how long ago we formed, we’d learn a tremendous amount about conditions elsewhere in the galaxy — and we could learn them in a matter of a few decades, rather than the tens of thousands of years currently required to send an unmanned probe to another solar system.

That’s an excellent reason to focus some probes on these Centaurs. Any time there’s a chance of gathering information in decades that would otherwise take tens of thousands of years, it’s worth exploring.

Feature image by NASA

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NASA Reveals Composition of Alien Comet

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Our solar system has most likely had many interstellar visitors over the eons, but we’ve only managed to spot a few. The first was ‘Oumuamua in 2017, but amateur astronomer Gennady Borisov spotted the object now known as 2I/Borisov late last year. Scientists have been able to take a closer look at this object as it nears the sun, even managing to analyze its composition. And it’s pretty, well… alien

Astronomers all over the world turned their telescopes toward 2I/Borisov in the months following the discovery, and among them was a team from NASA using the Atacama Large Millimeter/submillimeter Array (ALMA). While scientists now believe ‘Oumuamua is technically a comet, it’s very old and has lost most of the volatile materials that normally form the coma around a comet. 2I/Borisov, however, formed a bright, robust coma as it passed the sun a few months ago. 

The NASA team, operating out of Goddard Space Flight Center, turned ALMA toward the comet as it made its closest approach to the sun in late 2019. Radio telescopes are ideal for probing cold, low-energy gas like the outgassing from a comet. Peering inside the coma allowed the team to gather data on the objects chemical composition — these are quite possibly the first data points from an alien solar system. 

First, the team went looking for the most easily detectable gas in comets: hydrogen cyanide. Like the comets from our solar system, 2I/Borisov has plenty of that gas. The researchers were in for a surprise when they turned their attention to carbon monoxide, which is present at low levels in native comets. However, 2I/Borisov had many times more carbon monoxide than other comets. 

The table above shows the distribution of carbon monoxide levels in comets. 2I/Borisov is far out in front of most objects (keep in mind this is a logarithmic scale). The object to the far right is C/2016 R2, an anomalous object spotted by the PanSTARRS observatory in 2016. Carbon monoxide is the most volatile of compounds found in comets. This suggests that 2I/Borisov formed far away from its host star, but we don’t know why it has so much carbon monoxide. That might be indicative of all comets in 2I/Borisov’s home system. It could also be a fragment of a dwarf planet that was high in carbon monoxide. 

Sadly, we won’t be able to examine 2I/Borisov in greater detail to unravel the mystery. It’s moving too fast to remain in orbit of the sun — it’s already heading out into deep space again, never to be seen in our solar system again.

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This Is How Earth Would Look to Alien Astronomers

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It has been less than 30 years since the discovery of the first exoplanets, and we’re still in the dark when it comes to the possibility of life on any of them. Our techniques for finding other planets isn’t particularly sensitive, and we’re not even certain what signals we need to prioritize. A new study could shed light on that question by using the only habitable planet known to exist: Earth. 

The study comes from the California Institute of Technology’s Division of Geological and Planetary Sciences (GPS) and the NASA Jet Propulsion Laboratory, led by graduate student Siteng Fan. The goal was to start with a planet we know supports life (Earth), and work backward to extrapolate what an alien looking in our direction might see. In that way, Fan and the team hope to nail down the “look” of a life-supporting exoplanet. To do that, they used 9,740 images of Earth taken by NASA’s Deep Space Climate Observatory. They include data on light reflected from Earth in multiple wavelengths. 

At our current level of technology, we can’t directly observe exoplanets. They’re too small and dim compared with stars, but we can infer their presence via gravity or the way they obscure light from their parent stars. Often, the most we can say about an exoplanet’s habitability is whether it has a chance of harboring liquid water based on proximity to the star. 

The team discovered that the second principal component of Earth’s reflected light curve correlates to the fraction of land in the illuminated hemisphere. Using the original images, they were able to pick out the values matching land and cloud cover and applied them to a contour map (see top). The green highlighted areas are landmasses, and the blue is water — Africa is in the center, and Asia is to the right. North America is peeking in at the left edge. 

If we apply these same light curve values to a distant exoplanet, it could help us determine if there’s cloud cover and liquid water on the surface. Confirming that a planet has a water cycle could be a big step toward proving habitability. Will we actually be able to gather such data? It’s possible! Upcoming instruments like the James Webb Space Telescope and Thirty Meter Telescope could have enough resolution to pick up some reflected light from small, rocky exoplanets. We could be on the verge of finding more Earth-like worlds.

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This Alien Planet Is So Hot It Bleeds Metal

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There are thousands of confirmed exoplanets in the cosmos, and many of them are members of solar systems very different than our own. As missions like Kepler and the Transiting Exoplanet Survey Satellite (TESS) have highlighted more distant worlds, astronomers have been surprised how many of them have so-called “hot Jupiters.” WASP-121b is the hottest of these close-orbiting gas giants. How hot is it? It’s so hot that heavy metals leak out as it rockets around the star. 

WASP-121b made headlines in 2017 when scientists used Hubble to characterize its stratosphere. That was a first for any exoplanet, and it showed that the planet’s temperature increases along with the altitude, just like planets in our solar system. This is a hot Jupiter with 1.2 times the mass of Jupiter itself. It orbits a star about 900 light-years away that’s slightly larger and warmer than the sun, but it’s so close that its year is only 30 Earth days long. 

Even by the standards of a hot Jupiter, WASP-121b is absolutely scorching. At 4,600 degrees Fahrenheit (2,500 Celsius), it’s 10 times hotter than any other exoplanet yet discovered. While it’s only a little more massive than Jupiter, it’s diameter is almost twice as large because the intense heat from WASP-121 has caused it to swell. The new Hubble observations demonstrate what that intense heat means for the planet. 

The fluffed up outer layers of WASP-121b are under less gravity than the inner layers, so they fall away from the planet as it orbits. In most gas giants — even hot Jupiters — that would be largely hydrogen and helium. However, Hubble indicates that WASP-121b is losing heavy metals like magnesium and iron. Astronomers hypothesize the incredible heat is enough to lift heavy metals from the lower layers of the atmosphere upward where they can be lost to space. 

Exoplanet stratosphere

WASP-121b is too far away to image the atmosphere or trailing metallic gas directly, but Hubble can track the planet as it transits in front of its host star. The changes in light allow them to determine what’s happening to the exoplanet’s atmosphere via spectroscopy. Perhaps the most interesting aspect of the new analysis is what the hellish heat is doing to the planet’s shape. So much of the atmosphere is being pulled away that the planet probably looks a bit like a football. 

Scientists hope to learn more about this extreme planet in the future. The upcoming James Webb Space Telescope should be able to characterize its atmosphere even more accurately.

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Scientists: Sorry, ‘Oumuamua Still Isn’t an Alien Spaceship

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Astronomers have been pondering the nature of our first interstellar visitor ever since its discovery. ‘Oumuamua is bizarre — not only is it from beyond the stars, but it’s also long and cigar-shaped. That led some to wonder if it wasn’t really an alien spacecraft, but past studies of ‘Oumuamua have suggested that it’s just a space rock. Now, a comprehensive analysis from scientists at the University of Maryland and other institutions has ruined our fun once and for all. ‘Oumuamua isn’t an alien spaceship. 

While there have no doubt been alien objects in our solar system before, ‘Oumuamua was the first one we ever spotted. Astronomers at the Pan-STARRS observatory identified ‘Oumuamua in October 2017, but it was already on its way out of the solar system at that point. Its incredible speed and orbital eccentricity meant it could not have come from inside the solar system, but it was moving too fast for anything to catch up and take a closer look. 

It didn’t take long after the discovery for people to start half-jokingly wondering if ‘Oumuamua was an alien ship. Even if we ignore that, it took scientists a few tries to properly identify the object. The initial assumption was that ‘Oumuamua had to be a comet because comets would be easier to eject from the edges of a solar system. However, scientists couldn’t see a cometary tail (or coma) on ‘Oumuamua. After labeling it an asteroid, further analysis of its trajectory found evidence of slight out-gassing. Astronomers finally decided ‘Oumuamua was likely a very old comet. 

‘Oumuamua’s path through the solar system in 2017.

So, why is it definitely not an alien spaceship with a fuel leak or something? The team behind the new study included experts from a variety of fields to create a “big-picture summary” of ‘Oumuamua. They began with its origins, showing that there are several possible mechanisms by which an object like ‘Oumuamua could end up in interstellar space. Its behavior in our solar system, while strange, is also explainable with natural origins. In fact, its path around the sun matches a prediction published by one of the study authors six months before ‘Oumuamua’s discovery. 

‘Oumuamua is strange, but the study concludes there’s nothing unexplainable going on here. Jumping to the conclusion that it’s an alien spacecraft is fun, but the evidence does not support that. Astronomers hope to get a look at more alien visitors in the future. Upcoming instruments like the Large Synoptic Survey Telescope (LSST) will make it easier to spot small objects passing through the solar system. If we can find a few dozen alien space rocks, we might find that ‘Oumuamua is very typical of visitors from beyond the stars.

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Two Earth-Like Alien Planets Spotted Orbiting Nearby Star

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You can add two new entries to the growing list of potentially habitable exoplanets. Astronomers have spotted a pair of planets orbiting Teegarden’s Star, a red dwarf about 12 light years distant. The star is ancient, as are the planets orbiting it. So, if life was going to evolve there, it’s had plenty of time.

Teegarden’s Star is a red dwarf similar to Proxima Centauri but much older. Astronomers estimate that Teegarden’s Star could be as much as 8 billion years old. That’s almost twice the age of our Sun. It’s a member of a specific subclass known as ultra-cool M dwarfs and is only nine percent of the sun’s mass. Although it’s just 12 light years away, no one even noticed Teegarden’s Star until 2003.  

Astronomers from the Institute of Space Studies of Catalonia spent the last several years observing nearby low-mass stars for evidence of exoplanets. The team used the CARMENES spectrograph at Spain’s Calar Alto Observatory to track the movement of the target stars. This instrument can detect the small perturbations in the star’s motion as exoplanets revolve around them. This differs from the more common transit method used by instruments like Kepler. That involves watching for dips in light as planets pass in front of stars.

Because Teegarden’s Star is so small and cool, the habitable zone is much closer than it would be for a star like the Sun. The Catalonian team watched Teegarden’s Star for three years, taking more than 200 measurements. The numbers revealed two planets, both about 1.1 times the Earth’s mass. Teegarden’s Star b is the closer of the two, completing an orbit of the star in 4.9 Earth days. Teegarden’s Star c revolves around the star once every 11.4 days.

The Calar Alto Observatory.

Red dwarfs are known for their turbulent nature with frequent radiation surges and solar flares. The team had to rule out interference from such stellar phenomenons before considering the signals indicative of exoplanets. They are still technically just “candidate” exoplanets, though. Other teams will need to confirm the findings before they go on the planet list.

The presence of Earth-like planets around Teegarden’s Star is intriguing. It’s close by, and the star is very dim. That could make them easier to study than many other exoplanets. While red dwarfs are tumultuous, this one is very old and does not appear to be scorching the planets with flares. Perhaps we’ll find out one day these planets are habitable… or even inhabited.

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Life May Be Evolving on the Closest Alien Planet to Earth

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A few decades ago, we didn’t know if there were any planets outside our solar system. Thanks to advances in astronomy like Hubble and the Kepler Telescope, we now know there are uncountable planets in the universe, including at least one in the solar system next door. Researchers from Cornell University are taking a closer look at that planet, known as Proxima-b to determine if it might harbor life. They believe that it very well may, and the proof they cite is Earth.

Proxima-b orbits the red dwarf star Proxima Centauri, a mere 4.24 light years away from Earth. Scientists announced the discovery of Proxima-b in 2016. It orbits its parent star every 11.2 Earth days and has a mass at least 1.3 times that of Earth, suggesting that it has a rocky surface. As a red dwarf, Proxima Centauri is smaller and cooler than the sun, so liquid water might exist on Proxima-b even though it orbits very close to the star.

Most researchers consider the presence of liquid water essential to the development of life, so Proxima-b seems like a good candidate. However, the radiation from being so close to a red dwarf would make it inhospitable to us even if there’s water. The radiation might not be a deal-breaker for the development of alien life on Proxima-b, though. Lisa Kaltenegger and Jack O’Malley-James from Cornell modeled the surface ultraviolet radiation on four prominent exoplanets: Proxima-b, TRAPPIST-1e, Ross-128b, and LHS-1140b. It turns out, Proxima-b isn’t that bad compared with Earth’s past.

eso exoplanet

A less optimistic rendering of the planet Proxima b orbiting in the Goldilocks zone around the red dwarf star Proxima Centauri.

The team modeled various atmospheres for these exoplanets to see how the intense solar flares from red dwarfs affect the surface conditions. As expected, greater solar flare activity eroded the atmosphere. That’s not good news for the development of life, but to quote Dr. Ian Malcolm, “Life finds a way.”

The Earth of 4 billion years ago was a rough place bathed in radiation from a much younger version of our sun. All the exoplanet models showed less surface radiation than Earth would have had at that time. Life existed on Earth, so why not on Proxima-b? Organisms on Earth employ various biological mechanisms to guard against radiation like protective pigments and enhanced DNA repair molecules. Life may currently be thriving on Proxima-b in an environment we would find quite lethal.

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Passing Stars May Have Kept a Distant Alien World Tethered to Its Sun

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We tend to think of our Solar System as a static, constant environment. The implications of the protoplanetary disc and the demarcation line between our inward rocky planets, the outer gas giants, and the farthest “ice giants” all combine to create a nifty little model in which the heaviest bands of material with the most rock coalesced in the inner solar system, while large amounts of gas were diffused by the solar wind and blown into the outer reaches of the solar system. But one of the most profound findings of the past few decades has been the dynamism inherent in these systems.

Planets don’t just form statically and then remain in the same orbits for billions of years. Planets can migrate dramatically through a star system, thanks to interactions with each other and with their own stars. In one case, gravitational interaction with a passing binary may have actually saved a planet from being flung away from its host star.

HD 106906 b is an unusual world. It’s 11x the mass of Jupiter and located 738 AU from its host star. Neptune, for reference, is just 30.1 AU from the Sun on average. Its orbit is tilted out of the plane of the ecliptic, by 21 degrees. These are all extremely unusual data points, and they indicated that something had a major impact on the planet’s formation. Even Planet 9, the hypothetical super-Earth-sized disruptor that may be whizzing about in the depths of our own solar system, is only estimated to sit 400-800 AU from Sol, and it isn’t thought to be anywhere near 11x Jupiter mass if it exists at all. (11x the mass of Jupiter would be roughly 1 percent the mass of the Sun).

Scientists have been curious about HD 106906 b since we found it, and have worked out that a close binary passage about three million years ago may have impacted HD 106906 b’s position around its host star in a way that kept the planet from exiting the system altogether. Current thinking is that HD 10906 b was lobbed into an eccentric orbit after a close encounter with its own stars, until a passing circumbinary object nudged it back towards its primary, on an exceedingly unusual orbit.

These types of gravitational interactions may have been common in our own solar system. Triton, the largest moon of Neptune, contains over 99 percent of the mass in the Neptunian moon system and is extremely similar to Pluto in size and bulk composition. It orbits retrograde, which means it couldn’t have formed around Neptune in the first place. One line of thought is that Triton had a binary pair when it approached Neptune, but gravitational interactions led to the destruction or ejection of the binary, leaving Triton behind. There are models of our early solar system formation that predict a fifth ice giant (ejected due to gravitational interactions with Jupiter and Saturn). There’s another theory, known as the Grand Tack hypothesis, that posits that Jupiter’s inward migration to 1.5 AU choked the material available to form Mars before the gas giant migrated outwards again after Saturn was captured in orbital resonance.

Our own solar system may have been impacted by the type of stellar near-misses that characterize HD 106906, though none so dramatically. 70,000 years ago, Scholz’s Star passed within 0.82 light years of the Sun. This may explain the orbits of certain small objects in the solar system. They appear to have originated from an area of space that corresponds with the area Scholz’s Star would’ve disrupted as it moved past our own system.

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