This one is coming in fast, it has an eccentricity of over 6 with the current fits. For point of reference, 1I and 2I have eccentricities of 1.2 and 3.3.
Right now it is mostly just a point on the sky, it is difficult to tell if it is active (like a comet) yet. If it is not active, IE: asteroid like, then the current observations put it somewhere between 8-22km in diameter (this depends on the albedo of the surface). From what we know, we would expect it to likely be made up of darker material meaning given that range of diameters it is more likely to be on the larger end. However if it is active, then the dust coming off can make it appear much larger than it is. As it comes in closer to the sun and starts to warm up it may become active (or more active if its already doing stuff).
It will not pass particularly close to any planet. It will be closest to the sun just before Halloween this year at 1.35 au, moving at 68 km/s (earth orbits at 29-30 km/s). It is also retrograde (IE, it is moving in the opposite direction of planetary motion), for an interstellar object this is basically random chance that this is the case.
The next couple of weeks will be interesting for a bunch of people I know.
Source: Working on my PhD in orbital dynamics and formerly wrote the asteroid simulation code used on several NASA missions: https://github.com/dahlend/kete
Closest approach will be October 29, 2025. It’s currently passing Jupiter’s orbit. I’m amazed that even at this speed it will take that long to get here.
“Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is.” ~Douglas Adams
Sometimes it is hard to think of big space is, especially because we tend to do that while sitting around inside (this is where we have most of our thoughts, after all). Of course space distances are nothing like the distances inside our rooms, no frame of reference.
Instead, go out to the ocean on a clear day, and observe how absurdly vast the ocean is. Just ocean, as far as you can see. Look around and realize you’ve gained absolutely nothing in terms of comprehending the vastness of space, to which the difference between your room and the most sweeping views on Earth are just totally insignificant.
An even better visualization of the size of the Solar System. It shows traveling from the Sun out to forever at the speed of light. Be prepared to spend hours watching the paint dry. I suspect traveling in space will be like war, long periods of boredom punctuated by brief moments of sheer terror.
"On this scale, the Sun, by far the largest thing in our solar system, is only a ball about two-thirds of an inch (17 millimeters) in diameter sitting on the goal line — that's about the width of a U.S. dime coin. ...
The inner planets — Mercury, Venus, Earth and Mars — are about the size of grains of sand on a football field scale. They would be dwarfed by a typical flea, which is about 3 millimeters long.
Closest to the goal line is Mercury, just under a yard from the end zone (.8 yards to be specific). ... At this scale, Mercury's diameter would be scarcely as large as the point of a needle.
Venus is next. It is 1.4 yards from the end zone. ...
On to Earth, sitting pretty on the 2-yard line. ...
Mars is on the three-yard line of our imaginary football field. ...
Jupiter remains pretty close to our end zone on the 10.5-yard line. ...
Saturn is on the field at 19 yards from the goal line. ...
Uranus ... is about 38 yards from our end zone.
Neptune is where things start to get way out. It is 60 yards from our solar goal line on the imaginary football field. ...
Tiny Pluto is much closer to the opposing team's end zone. It's about 79 yards out from the Sun ...
On this scale, our little friend Voyager 1 has left the game and is well out in the stadium parking lot or beyond."
From the simulation you linked looks like it is passing closeish to the Mars... but I do know that space is big. However, I am curious of what would happen if an object of this magnitude hit mars at 90km/s.
Would be wild if a sufficiently large object with a lot of water and organic molecules hit Mars, ejected a lot of material in to Mars’ orbit to then go on to form a sufficiently large moon that tidally massaged Mars’ core to cause a dynamo to generate a sufficiently strong magnetic field to…
in a somewhat related story, I was on a beach in Costa Rica last week, watching some spider monkeys in a palm tree trying to whack open small nuts. Just then, an American family walked up the beach with two teenage boys. They didn't notice the monkeys I was watching. But one of the boys grabbed a coconut off the sand and became determined to break it open with a rock in front of his parents. So watching the monkeys and the boy simultaneously, I had the distinct feeling of how slowly evolutionary, let alone geological, processes actually move.
“We'll be saying a big hello to all intelligent lifeforms everywhere and to everyone else out there, the secret is to bang the rocks together, guys.” - The Hitchhikers Guige to the Galaxy, Douglas Adams
But are you implying that we are somehow more evolved than the monkeys? Both the human and the monkey in the story have evolved for the same amount of time since our last common ancestor.
That argument always struck me as vacuous. Dump a barrel of ball bearings on the top of a craggy hill. Wait as they all bounce around, some getting stuck in local minima and some bouncing over obstacles and covering large distances.
Would you claim that they all traveled the same distance because they all traveled for the same amount of time?
Evolutionary space is very high dimension, which makes the argument that just projecting onto the (1d) time axis is misleading even stronger.
I'm not sure more/less evolved is a meaningful concept in Darwinian terms. Organisms have a level of fitness for their environment. Perhaps you are talking about cultural evolution?
frame of reference matters,
from the center of the sun or galactic core they all most certainly moved the same distance in the same amount of time and it was much further than the hill was tall.
Sure? What is the analog to this other frame of reference in the evolution case though? Or are you just stepping out of the analogy's applicability range to show that it can be pushed too far (which is of course true of an analogy)?
A Molecular clock would be gravity in your model, when ever you called stop
all your marbles would have experienced the same amount of gravitational force.
That is the intent of "experienced the same amount of evolution" and similar.
Where I see the model flounder is; the hill provides the fitness context. You implied distance "means" more evolved, but for life it is all about making it to the next round, in your marble game how many of those furthest marbles will ever be found for the next round?
With life big changes are dangerous,
you may find yourself improved out of options.
If it would be so bad, Earth's polar regions (experiencing aurora borealis) would be inhabitable too. Earth's magnetic field is not magically neutralizing all charged particles from the Sun, just diverts them (some maybe away, but many simply towards poles).
And clearly even our mag field (and Sun's heliosphere) is not enough to shield us from those crazy cosmic rays.
It’s not worth doing because it is easier, but because all of our eggs are in one basket (planet). We know of disasters that can wipe out almost all life on a single planet. Of course, there are also disasters that can wipe out all life in one star system (and one region of the Galaxy). So, ideally we need to colonize many worlds in many different parts of the Galaxy, but baby steps. Step one is to have a sustainable population on multiple moons/planets/stations of this star system before we jump to other star systems.
Assuming it’s at the upper range of the size estimate above, and of average rocky density, the kinetic energy of the impact would be something like a 10 billion megaton nuke.
If we could steer it to hit one of Mars’s poles, it might do a bit of terraforming for us!
Where did my math go wrong? I got about 50,000 megatons. Assuming the high-end of 22km and a rocky/metallic density of 5000 kg/cubic meter (and assuming it's a cube):
kinetic energy = 1/2 m v**2 = 1/2 * size * density * v**2
= 1/2 *(22000 m)**3 * (5000 kg/m**3) * (90 m/s)**2 / (4.184E15 J/megaton)
= 52,000 megaton
If it's an icy comet then the density is more like 500 kg/cubic meter, or 1/10th that number.
I can not confirm this; the parent calculation is the correct one. I can't immediately find what your error was. (edit: It's your [km/s]—you wrote [m/s] by mistake).
(let* ((ρ ([g (cm -3)] 5))
(d ([km] 22))
(m (* ρ (expt d 3)))
(v ([km (s -1)] 90))
(ke (* 1/2 m (expt v 2)))
(kg-tnt ([J (kg -1)] 4.2e6)))
(values (/ ke kg-tnt)
(as [megaton] (/ ke kg-tnt))))
5.133857142857142e19 [KG]
5.133857142857143e10 [MEGATON]
How fast does something need to be traveling before you’d consider it to be fast? It probably weighs as much as a city and it is traveling tens of times faster than a high-velocity bullet.
It is of the same caliber as the dinosaur ending meteorite. The planet barely shrugged from it. There is suspicion that something the size of pluto has already hit mars once upon a time. And it is way more massive than this speck of cosmic dust.
Thanks for sharing this info. Does "eccentricity" refer to the orbit, or the shape of the object?
For ‘Oumuamua in 2017, some method was used to determine its shape, which is (apparently) remarkably elongated. Is it possible to determine the elongation of the new object?
Eccentricity refers to the shape of the orbit, derivable from the highest and lowest distances in the orbit of the orbiting body (there's actually a bunch of ways to calculate it that are mathematically equivalent). It's related to modeling orbits as conic sections. An eccentricity of 0 is a perfect circle, <1 is a normal elliptical orbit, >=1 is an escaping trajectory.
For example, Earth's orbit around the sun is ~0.0167, Pluto's is 0.248.
An object (depending on consistency) of about 100m is enough to wipe out a city and do enough damage to the environment. Something of 8-20km is in the same category as what wiped out the dinosaurs (10-15km).
Huh. It looks like on 10/2 it will make its closest pass to a planet, Mars, and on that date it also is in a straight line with Mars, Mercury and the sun, while Earth and Venus are roughly opposite each other. Do you know if this sim accounts for solar or martian gravity diverting its trajectory?
This orbit visualization uses a simple 2 body approximation, so only the sun. This is because unless an object has a VERY close approach to a planet the two body approximation is more then enough for this style of visualization.
I did a full proper n-body integration and it is not visually different than this.
It is also a factor of where our surveys look on the sky. A lot of asteroid surveys have biases to look at the plane of our solar system (since this is where a lot of asteroids are).
It is probably random chance, however there may be some biases from where they come from on the sky (I know people who work on that, but I don't know much about it).
N=3 does not provide very robust statistics yet, give us another decade or two.
I can't believe that all those super-intelligent astronomers, who spend hours on their own in the dark, couldn't come up with a better name than 'Extremely Large Telescope'. ;0)
Thanks for sharing your expertise! What really bends my mind is the relative speeds involved. Reddit's /r/space has a great visual[1] which depicts it as basically going straight through our solar system, only bending slightly as it passes Sol. This is only possible if the object moving at 68 km/s is also moving sideways at 230 km/s so as to match our galactic orbit, and moving up at a mind-boggling 600 km/s (relative to CMB). This is all basic stuff of course, but something about having the object actually pass by us is making it more real than usual...
Hell, maybe it's only orbiting the galaxy at a leisurely 160 km/s, and from its perspective we're a spinning disc of chaos zipping past it for the first time in a few million years! I don't even know how I would start to analyze its orientation in relation to the galactic center, but I'll be keeping this as my little "headcannon" until proven wrong, that's for sure.
Are you able to calculate whether, by any chance, it will come close to any of the NASA probes around Jupiter, Mars, Venus, etc...? What is its closest approach to the JWST?
The closest it will come is Mars, but when I say close these are quite literally astronomical distances, about 0.2 au from Mars. This is about 75x further than the moon is from the Earth.
If it is an inactive rock, then we will not see it as any more than a point of light during its visit.
Judging by how humanity didn't see any of those for millennia and now three in just several years, I can propose two hypotheses:
1. Astronomers became good enough to notice them
2. These rocks are first in an incoming flood of such objects, the Universe decided to destroy humanity.
Maybe. The solar system was in this galactic position about 250 million years ago (one galactic year) and there was a major extinction event around that time
We hadn't the means to discover them for most of the last millennia, so now being good enough is obvious. But the question is why now, and not 10 or 20 years ago. It might be that we had the ability for a longer time already, but it just never "clicked" until now to recognize them. It is also possible that we really just got good enough recently. Or even that until now, there really were none in the last decade we could find, and we are just lucky(?) that now more are coming our way.
We might know this better in the next years, depending on whether there will now be an explosion of dozen and dozens of new interstellar objects discovered, or not. It might be another rush, like with exoplanets and local dwarf-planets.
I believe #1 is true; but not #2.
It's just that those rocks are more common than we thought.
And we thought they were uncommon because we weren't able to spot them... yet.
Benevolent aliens are planting incompetent people in positions of power so that we are perpetually on the verge of self-annihilation. But this is all to save us from the malevolent aliens who would obliterate us if they thought we had any chance of survival.
This object is near the solar system's orbital plane - far closer than Halley's comet, for example.
People have searched off the orbital plane for a long time, if only to find new comets.
This object was found by ATLAS, the Asteroid Terrestrial-impact Last Alert System. The project goal is to identify near-earth asteroids, evaluate the risk they might impact the Earth, and alert others if impact is predicted.
The project started in 2015, two years before ʻOumuamua. It was not made specifically to find interstellar objects transiting the solar system.
un-nervingly near the orbital plane, as the depiction shows the object passing just above, on approach, and juct below, on departure, of the orbital plane of mars
given the low relative speed of these objects so far, we can define them as extra solar, something exra galactic could be moveing at fractional light speed relative to us and be almost impossible to see and track unless it was realy big and close, and as there are confirmed exra galactic stars, it is not conjecture to to then include rouge planets and asteriods ,etc in the list of signatures to be looking for, and perhaps dismissed from previous data as bieng equipment artifacts or noise.
In a thread elsewhere I saw "Interstellar Objects in the Solar System:
1. Isotropic Kinematics from the Gaia Early Data Release 3" (https://arxiv.org/pdf/2103.03289) mentioned.
In there, one estimate of the number of these objects is
Nisc <~ 7.2 × 10−5 AU−3
Which (my, probably wrong, calc) implies roughly one inside the orbital volume at the radius of Saturn's orbit at any time.
The first two were used up, empty deceleration stages of a giant alien spaceship, discarded during interstellar cruise while the rest of the assembly kept burning for its years long deceleration from relativistic speeds. This is the main ship.
Maybe. I think it's more likely that an alien probe - assuming there are aliens and they fly probes - would be the size of a cubesat, and we wouldn't even notice it.
Perhaps Oumuamua was the mothership and the solar system is now swarming with cubesats we're not noticing.
This is an announcement from the Minor Planet Center (MPC).
They are the official international clearing house for observations of solar system objects.
The top indicates that the object has two names (this is common):
3I/ATLAS = C/2025 N1 (ATLAS)
ATLAS was the telescope that made the discovery.
The list of data are individual observations of the object by different telescopes. This observation format has been in use for a long time, but is being phased out. A row is meant to fit on a single punch card...
These observations are then used to calculate orbits, the MPC calculates the orbit as well, but this list of observations is also ingested by JPL and their Horizons service.
Wow. The 2019 novel “The Last Astronaut” hypothesized about a fictional interstellar object coming into the solar system, called “2I” in the novel for short, but back here in real life, we’re already up to 3I.
If we're just talking about interstellar objects, and assuming a decent lead time (not oh hey it's going to hit in 3 days), it's probably easier to prevent it from hitting us since it's most likely just passing through. You'd only need to give it a small enough nudge to have it miss a smidge. That's something we're more than capable now of doing, and have done.
If this object were coming straight for Earth there would be pretty much nothing we could do to avoid a collision. Luckily the chances of such a collision are enormously small. We are fortunately bringing more resources on line to find such objects sooner.
ELT will not discover many new objects, it's built to do deeper followup observations of known targets. On the other hand, Vera Rubin was designed to be a survey telescope, repeatedly imaging the entire night sky to discover new objects. It will not do targeted observations, or at least very few.
How do they plot the path of these things without knowing its weight and size? Seems like bullshit, especially when they specifically say "the sun will barely affect it" ?? The sun affects everything in proportion to the things you exactly dont yet know, doesn't it?
A very rough calculation would suggested that the cylinder that goes from our solar system to Proxima Centauri contains 5000 similarly sized objects moving at the same speed:
1 object crossing the solar system plane every 5 years at 60km/s
+
Proxima Centauri is approximately 5 light years away
=>
there are `speed of light / 60km/s` objects in the cylinder.
You can go outside at night and see big rocks floating. If space is so empty, how is it possible that you can see them with your own eyes?
We live in a patch of space that's not that empty. Maybe that interstellar rock floated from other patch of space that's not that empty all the way over here, all on its own.
Most rocks we see in our patch of space, as far as we can possibly know, were not intentionally launched.
We updated the URL to the ABC news report as it's more understandable to lay people, at least those like me. If someone finds a better report, let us know and we'll be happy to update it.
