The Vera Rubin Observatory could find dozens of interstellar objects
Scientists and astronomers are racing to study only the third-ever known interstellar visitor to the solar system, but with a powerful new observatory coming online, these enigmatic objects may soon become routine discoveries.
A comet, now known as 3I/ATLAS, with 3I short for "third interstellar," sparked immediate excitement on July 1 when it was detected by the Deep Random Survey remote telescope in Chile, exhibiting a hyperbolic and highly eccentric orbit.
It is the third confirmed interstellar visitor, following 1I'Oumuamua in 2017 and 2I/Borisov in 2019. But fleeting visits of high-speed guests from outside our solar system are likely to be detected much more regularly now, thanks to the new Vera C. Rubin Observatory.
The Rubin observatory is located on the mountain of Cerro Pachón in Chile, and saw first light in June after a decade of construction. While it is only in its early commissioning phase, in just 10 hours of observations, Rubin discovered 2,104 new asteroids. Its science objectives include understanding the structure and evolution of the universe, mapping the Milky Way and observing transient astronomical events, but it is also set to revolutionize the detection of interstellar objects (ISOs).
This is thanks to Rubin's gigantic Large Synoptic Survey Telescope (LSST) camera— the largest digital camera ever constructed for astronomy, with a staggering 3.2 gigapixels. LSST will scan giant swaths of the sky at once and observe the entire southern sky every few nights. Due to its wide field, depth, and how frequently it observes the same regions of sky, Rubin is uniquely capable of catching fast, faint objects like 1I/'Oumuamua or 3I/ATLAS.
ISOs like 1I/'Oumuamua or 3I/ATLAS move quickly and can easily pass through our sky unnoticed if the sky is not being scanned often and everywhere. Rubin will be looking constantly and broadly, giving astronomers the best chance yet to catch these fleeting visitors, while also being able to detect objects fainter than nearly any ground-based survey before it. Rubin's powerful imaging and automatic image comparison, coupled with an automated alert system — with millions triggered and filtered every night — means it will pick up telltale motion and flag a potential ISO.
So how many interstellar objects might Rubin actually detect? The answer varies widely depending on which assumptions scientists use.
We are in the early days of detecting ISOs, so it is difficult to estimate how many Rubin is likely to pick up; we know little about their overall frequency, size range, brightness, if they exhibit cometary activity, and how LSST performs.
However, a few recent papers on the topic provide some useful context for how many ISOs LSST might be able to detect, depending on a range of variables.
In a 2022 paper, Hoover et al. estimate that LSST will detect on the order of between 0.9-1.9 ISOs every year, or around 15 such objects across Rubin's 10-year observational campaign. It notes that these are lower limits, which can be updated when there is more data on the number density and size frequency of interstellar objects.
Additionally, Hoover et al. estimate the chances that Rubin will find an ISO reachable by the Comet Interceptor and Bridge mission concepts, which would fly by an interstellar object as it passes through our solar system. These missions would be launched to lurk in wait, ready to intercept and rendezvous with a passing ISO. The researchers concluded that there is just a roughly 0.07% chance that LSST would identify an ISO target available to Comet Interceptor, which has limited capability to change its velocity, while LSST could detect around three to seven ISOs reachable by Bridge, a more capable but yet-to-be-approved mission concept.
RELATED STORIES
— New interstellar object 3I/ATLAS: Everything we know about the rare cosmic visitor
— Vera C Rubin Observatory reveals 1st stunning images of the cosmos. Scientists are 'beyond excited about what's coming'
— 'Oumuamua: A guide to the 1st known interstellar visitor
Another estimate, from a 2023 paper by Ezell and Loeb, expects LSST to detect one small ISO 3 to 164 feet (1 to 50 meters) wide every one to two years.
A more optimistic assessment comes from Marceta and Seligman in a 2023 paper. They find, based on a simulated suite of galactic populations of asteroidal interstellar objects and their trajectories and kinematics, that Rubin should detect between around 0 and 70 asteroidal interstellar objects every year. Again, one of the main factors is how many objects of different sizes actually exist in the population of ISOs, as well as their albedo, or how much light they reflect.
With just three confirmed interstellar visitors so far, much remains unknown about the number, size, and diversity of ISOs. But with the Rubin Observatory coming online, sightings of these fast-moving cosmic messengers may soon shift from rare events to regular science, offering unique insights into the galaxy beyond our solar system.
Solve the daily Crossword
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Yahoo
16 hours ago
- Yahoo
Interstellar Meteors Hit Earth All the Time but Still Elude Astronomers
Astronomers think small space rocks from beyond our solar system routinely strike Earth—but proving it isn't easy Aliens are visiting our solar system. Not little green men, sadly, but natural alien objects—cosmic bodies such as comets and asteroids born elsewhere in the galaxy that zip by the sun as they drift through the Milky Way. They're not so much visiting as just passing through. Though these objects were speculated to exist for a long time, we didn't know they were out there for sure until October 2017, when astronomers noticed a small body moving through space at exceptionally high speed. Observations over just a few nights showed it was moving far too quickly to be orbiting the sun and thus must have come from some other star. It was our first known interstellar visitor. [Sign up for Today in Science, a free daily newsletter] Eventually designated 1I/'Oumuamua, it was 30 million kilometers from Earth and already outward bound from the solar system when it was discovered, offering scant time for follow-up studies. But then, less than two years later, a second such object was found, also moving far faster than usual. 2I/Borisov turned out to be a comet very similar to those we're familiar with, except for its trajectory, which clearly showed it came from interstellar space. And now a third such alien body is barreling through the solar system: 3I/ATLAS, moving so rapidly its path is barely bent at all by the sun's gravity as it zooms past. In science, one is an anomaly and two might be coincidence, but three is a trend. Clearly, objects like this are passing by on the regular. Roughly speaking, there could be ones 100 meters in size or larger passing through the inner solar system at any time. Given their speed and intrinsic faintness, though, they're difficult to detect. We also know that when it comes to things such as asteroids and comets, nature tends to make many more smaller ones than bigger ones. In our own solar system, for example, only a couple of dozen main-belt asteroids are bigger than 200 km wide, but more than a million are 1 km across or larger. This generalization should hold for interstellar interlopers as well. For every kilometer-scale one that we see, there should be far more that are smaller. In fact, there could be millions of sand-grain-sized alien objects whizzing past us right now. And we already know that they're out there: in 2014 astronomers announced they had found seven grains of cosmic dust brought down to Earth from the Stardust space probe, which was designed to catch material ejected from a comet. Also, embedded in some meteorites that have hit Earth are tiny bits of material, called presolar grains, that are so old they actually formed around other stars. They got here after being blown across the void of space into the collapsing cloud of gas and dust that formed the sun and planets 4.6 billion years ago. Larger material could be ejected from an alien planetary system if it's given a gravitational assist when passing by a planet there, or it could be torn away from its parent star by another star passing closely to that system. So it seems certain interstellar jetsam would occasionally hit our planet. Earth is a small target, but with so many galactic bullets, you'd think some would actually find their way to our planetary bull's-eye. The problem is detecting them. Every day Earth is hit by very roughly 100 tons of locally grown interplanetary debris—material ejected from asteroids and comets native to our solar system—which translates into billions of tiny specks zipping across our sky daily. Detecting the tiny fraction that have an interstellar origin is tough. And the difficulty is not just in the sheer numbers. It's in tracing the trajectories of that small handful across the sky back up into space to calculate their orbits. When an object such as a planet or an asteroid orbits the sun, we say it's gravitationally bound to our star. That orbit in general is an ellipse, an oval shape. These can be defined mathematically, with the key factor being the eccentricity: how much the ellipse deviates form a circle. A perfect circle has an eccentricity of 0, and the higher the eccentricity, the more elliptical the orbit, up to a value of just under 1. An orbit with an eccentricity of 0.99, say, is extremely elongated; you might find that an object dropping down very close to the sun from the outer solar system has an eccentricity that high. It's possible to have an eccentricity higher than 1 as well. That kind of trajectory is called hyperbolic—named after the mathematical curve, not because it's exaggeratedly over-the-top—and an object on this path is not bound to the sun gravitationally. Once it's heading out, it's gone forever. It ain't coming back. This is how we know 'Oumuamua, Borisov and ATLAS are from interstellar space; each has an eccentricity greater than 1—'Oumuamua's is about 1.2 and Borisov's 3.4, which is quite high, but ATLAS has them both beat with an astonishing eccentricity of 6.2. That's extraordinarily high and also indicates it's hauling asteroid (or, more accurately, it's not comet back). Do we see any meteors with eccentricities like these? If the exact path of a meteoroid (the term for the solid bit that burns up in the air and becomes a meteor) through Earth's atmosphere can be determined, that can be backtracked up into space, allowing the object's trajectory, including its eccentricity, to be calculated. This can be done with multiple sky cameras set up in various locations; if a meteor streaks across their field of view, the multiple vantages can allow astronomers to triangulate on the rock and measure its path. There are quite a few such camera networks. It's actually difficult getting good enough data to determine solid orbits for meteoroids, though. Many do have eccentricities very close to 1; these likely come from long-period comets that originate out past Neptune. NASA's Jet Propulsion Laboratory maintains a database of bright fireballs—exceptionally luminous meteors—at the Center for Near-Earth Object Studies (CNEOS). The earliest recorded meteors in the database date back to 1988, so there is a rich hunting ground in the data. Are any of the meteors listed hyperbolic? Unfortunately, no. At least, not unambiguously—there have been false positives but nothing clear-cut. Additionally, a study from 2020 looked at 160,000 measurements by the Canadian Meteor Orbit Radar covering 7.5 years. The researchers found just five potential interstellar meteors. The results aren't quite statistically strong enough to claim detections for sure, but they're very compelling. What we need are more eyes on the sky, more meteor camera networks that can catch as many of these pieces of cosmic ejecta burning up in our atmosphere as possible. It's a numbers game: the more we see, the more likely we'll see some that are not from around here. The science would be, well, stellar: these meteors can tell us a lot about the environments around other stars, the ways they formed and perhaps even the stars they come from. We're getting physical samples from the greater galaxy for free. We should really try to catch them. Hat tip to planetary scientist Michele Bannister for the link to the CNEOS article. Solve the daily Crossword
New York Post
a day ago
- New York Post
‘Possibly hostile' alien threat detected in unknown interstellar object, a shocking new study claims
A mysterious intergalactic object could potentially be a 'hostile' alien spacecraft that's slated to attack our planet in November, according to a controversial new study by a small group of scientists. 'The consequences, should the hypothesis turn out to be correct, could potentially be dire for humanity,' the researchers wrote in the inflammatory paper, which was published July 16 to the preprint server arXiv, South West News Service reported. 3 Comet 3I/ATLAS streaks across a dense star field in this image captured by the Gemini North telescope's Gemini Multi-Object Spectrograph, July 2025. NSF NOIRLab/ Ob et al. / SWNS Advertisement Dubbed 3I/ATLAS, the interstellar entity was discovered on July 1, rocketing toward the sun at more than 130,000 mph, Live Science reported. Less than 24 hours later, it was confirmed to be an interstellar object with initial observations suggesting that it could be a comet that measures up to 15 miles in diameter — larger than Manhattan. However, in the new paper, the trio of researchers suggested that it might be a piece of extraterrestrial spy technology in disguise. One of the researchers, Avi Loeb — a prominent Harvard astrophysicist known for linking extraterrestrial objects to alien life — previously made waves after floating the theory that 2017 interstellar object ʻOumuamua could be an artificial recon probe sent by an alien civilization, based on its odd shape and acceleration. Advertisement In this study, which he collaborated on with Adam Hibberd and Adam Crowl of the Initiative for Interstellar Studies in London, Loeb postulated that 3I/ATLAS's trajectory suggests a similarly alien origin. The trio felt the object's speed — which was significantly faster than ʻOumuamua and other objects — and the fact that it entered our solar system from a different angle than its predecessors offer 'various benefits to an extraterrestrial intelligence,' Loeb wrote in a blog post. 3 'The consequences, should the hypothesis turn out to be correct, could potentially be dire for humanity,' the researchers wrote in the inflammatory paper. ESA/Hubble/NASA/ESO/ / SWNS One benefit is that 3I/ATLAS will make close approaches to Jupiter, Mars and Venus, which could allow aliens to stealthily plant spy 'gadgets' there, Loeb wrote. Advertisement When the so-called undercover UFO reaches its closest to the Sun (perihelion) in late November, it will be concealed from Earth's view. 'This could be intentional to avoid detailed observations from Earth-based telescopes when the object is brightest or when gadgets are sent to Earth from that hidden vantage point,' Loeb declared. If this anomaly is a 'technological artifact,' this could support the dark forest hypothesis, which argues we haven't found signs of extraterrestrial entities because they are remaining undercover to shield themselves from predators or prey. Loeb warns that this could suggest that an attack is likely and would 'possibly require defensive measures to be undertaken.' 3 The Deep Random Survey telescope managed to capture images of interstellar object 3I/Atlas (pictured) in July 2025. K Ly/Deep Random Survey / SWNS Advertisement The problem is that 3I/ATLAS is traveling too fast for an Earth-based spacecraft to intercept it before it exits the solar system. 'It is therefore impractical for earthlings to land on 3I/ATLAS at closest approach by boarding chemical rockets, since our best rockets reach at most a third of that speed,' Loeb wrote. However, other scientists have thrown cold water on the so-called alien origins of the object, which they believe is a comet. 'All evidence points to this being an ordinary comet that was ejected from another solar system, just as countless billions of comets have been ejected from our own solar system,' added Samantha Lawler, an astronomer at the University of Regina in Canada who studies solar system dynamics, Live Science reported. In fact, even Loeb admitted in his blog that his alien spy probe theory is a bit far-fetched: 'By far, the most likely outcome will be that 3I/ATLAS is a completely natural interstellar object, probably a comet.' The researchers also warned the public to take the paper, which has not yet been peer-reviewed, with a grain of salt. 'This paper is contingent on a remarkable but, as we shall show, testable hypothesis, to which the authors do not necessarily ascribe, yet is certainly worthy of an analysis and a report,' they wrote. 'The hypothesis is an interesting exercise in its own right, and is fun to pursue, irrespective of its likely validity.' Advertisement However, critics have called their project a mockery of the work of other scientists, who have provided plenty of evidence that 3I/ATLAS is not evidence of a pending close encounter. 'Astronomers all around the world have been thrilled at the arrival of 3I/ATLAS, collaborating to use advanced telescopes to learn about this visitor,' Chris Lintott, an astronomer at the University of Oxford who helped simulate 3I/ATLAS's galactic origins, told Live Science. 'Any suggestion that it's artificial is nonsense on stilts, and is an insult to the exciting work going on to understand this object.'
Scientific American
a day ago
- Scientific American
The Sky Is Falling—From Another Star
Aliens are visiting our solar system. Not little green men, sadly, but natural alien objects —cosmic bodies such as comets and asteroids born elsewhere in the galaxy that zip by the sun as they drift through the Milky Way. They're not so much visiting as just passing through. Though these objects were speculated to exist for a long time, we didn't know they were out there for sure until October 2017, when astronomers noticed a small body moving through space at exceptionally high speed. Observations over just a few nights showed it was moving far too quickly to be orbiting the sun and thus must have come from some other star. It was our first known interstellar visitor. On supporting science journalism If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today. Eventually designated 1I/'Oumuamua, it was 30 million kilometers from Earth and already outward bound from the solar system when it was discovered, offering scant time for follow-up studies. But then, less than two years later, a second such object was found, also moving far faster than usual. 2I/Borisov turned out to be a comet very similar to those we're familiar with, except for its trajectory, which clearly showed it came from interstellar space. And now a third such alien body is barreling through the solar system: 3I/ATLAS, moving so rapidly its path is barely bent at all by the sun's gravity as it zooms past. In science, one is an anomaly and two might be coincidence, but three is a trend. Clearly, objects like this are passing by on the regular. Roughly speaking, there could be ones 100 meters in size or larger passing through the inner solar system at any time. Given their speed and intrinsic faintness, though, they're difficult to detect. We also know that when it comes to things such as asteroids and comets, nature tends to make many more smaller ones than bigger ones. In our own solar system, for example, only a couple of dozen main-belt asteroids are bigger than 200 km wide, but more than a million are 1 km across or larger. This generalization should hold for interstellar interlopers as well. For every kilometer-scale one that we see, there should be far more that are smaller. In fact, there could be millions of sand-grain-sized alien objects whizzing past us right now. And we already know that they're out there: in 2014 astronomers announced they had found seven grains of cosmic dust brought down to Earth from the Stardust space probe, which was designed to catch material ejected from a comet. Also, embedded in some meteorites that have hit Earth are tiny bits of material, called presolar grains, that are so old they actually formed around other stars. They got here after being blown across the void of space into the collapsing cloud of gas and dust that formed the sun and planets 4.6 billion years ago. Larger material could be ejected from an alien planetary system if it's given a gravitational assist when passing by a planet there, or it could be torn away from its parent star by another star passing closely to that system. So it seems certain interstellar jetsam would occasionally hit our planet. Earth is a small target, but with so many galactic bullets, you'd think some would actually find their way to our planetary bull's-eye. The problem is detecting them. Every day Earth is hit by very roughly 100 tons of locally grown interplanetary debris—material ejected from asteroids and comets native to our solar system—which translates into billions of tiny specks zipping across our sky daily. Detecting the tiny fraction that have an interstellar origin is tough. And the difficulty is not just in the sheer numbers. It's in tracing the trajectories of that small handful across the sky back up into space to calculate their orbits. When an object such as a planet or an asteroid orbits the sun, we say it's gravitationally bound to our star. That orbit in general is an ellipse, an oval shape. These can be defined mathematically, with the key factor being the eccentricity: how much the ellipse deviates form a circle. A perfect circle has an eccentricity of 0, and the higher the eccentricity, the more elliptical the orbit, up to a value of just under 1. An orbit with an eccentricity of 0.99, say, is extremely elongated; you might find that an object dropping down very close to the sun from the outer solar system has an eccentricity that high. It's possible to have an eccentricity higher than 1 as well. That kind of trajectory is called hyperbolic—named after the mathematical curve, not because it's exaggeratedly over-the-top—and an object on this path is not bound to the sun gravitationally. Once it's heading out, it's gone forever. It ain't coming back. This is how we know 'Oumuamua, Borisov and ATLAS are from interstellar space; each has an eccentricity greater than 1—'Oumuamua's is about 1.2 and Borisov's 3.4, which is quite high, but ATLAS has them both beat with an astonishing eccentricity of 6.2. That's extraordinarily high and also indicates it's hauling asteroid (or, more accurately, it's not comet back). Do we see any meteors with eccentricities like these? If the exact path of a meteoroid (the term for the solid bit that burns up in the air and becomes a meteor) through Earth's atmosphere can be determined, that can be backtracked up into space, allowing the object's trajectory, including its eccentricity, to be calculated. This can be done with multiple sky cameras set up in various locations; if a meteor streaks across their field of view, the multiple vantages can allow astronomers to triangulate on the rock and measure its path. There are quite a few such camera networks. It's actually difficult getting good enough data to determine solid orbits for meteoroids, though. Many do have eccentricities very close to 1; these likely come from long-period comets that originate out past Neptune. NASA's Jet Propulsion Laboratory maintains a database of bright fireballs —exceptionally luminous meteors—at the Center for Near-Earth Object Studies (CNEOS). The earliest recorded meteors in the database date back to 1988, so there is a rich hunting ground in the data. Are any of the meteors listed hyperbolic? Unfortunately, no. At least, not unambiguously —there have been false positives but nothing clear-cut. Additionally, a study from 2020 looked at 160,000 measurements by the Canadian Meteor Orbit Radar covering 7.5 years. The researchers found just five potential interstellar meteors. The results aren't quite statistically strong enough to claim detections for sure, but they're very compelling. What we need are more eyes on the sky, more meteor camera networks that can catch as many of these pieces of cosmic ejecta burning up in our atmosphere as possible. It's a numbers game: the more we see, the more likely we'll see some that are not from around here. The science would be, well, stellar: these meteors can tell us a lot about the environments around other stars, the ways they formed and perhaps even the stars they come from. We're getting physical samples from the greater galaxy for free. We should really try to catch them.
