I'm one of those astronomers! I'm working on my PhD in orbital dynamics.
A lot of people are requesting discretionary time on telescopes trying to get observations in. The orbit will put us on the other side of the sun when 3I is nearest the sun in october, we can see it now and after it comes back out from behind the sun.
Unfortunately, right now the it is in a very crowded star field (IE, its close to the galactic plane, lots of stars in the background).
If you are interested in orbital dynamics, I have an open source rust/python package for accurate orbital calculations of asteroids/comets:
Cool to see! I spent a few years working on asteroid orbital dynamics too. What integrator are you using? Do you cover the weird stuff like Yarkovsky effects? That gets important for NEO impact risk, which is what I worked on.
Matt Holman's ASSIST (https://github.com/matthewholman/assist) struck me as a breath of fresh air, coming from openorb and its kin.
I wrote a custom implementation of the Radau integrator, its been heavily modified. I have a lot of additional physics, it supports the non-gravitational models that JPL Horizons defaults to, so diurnal yarkovsky at least. I've been using it to study dust and small object dynamics, as they get pushed around by the sun a lot.
It does an OK job for impactors, but the integrator is tuned heavily for performance, and the tolerance defaults are not great for impactors.
I match jpl horizons for apophis to a few km, they have a lot more intense earth gravitational model then I care to implement, and by default I only include the 5 heaviest main belt asteroids, they have many more. That was the sweet spot for accuracy vs speed for me, overall accuracy goal is less than a few km over a decade.
The goal is to be able to handle the huge influx of new asteroids that the catalog will have due to LSST and eventually NEO Surveyor (which I worked on for 3 years). Most systems I know have been throwing hardware at the problem, I tried to make fast and efficient enough software that we can use it on a laptop for 5-10 million asteroids.
You might want to try OrdinaryDiffEq.jl. As of last summer, we have really fancy radau methods that are arbitrary order, arbitrary tolerance (see https://arxiv.org/abs/2412.14362 for the paper)
That is very impressive - getting the nongravs is a lot of work.
Anything published on your integrator and its modifications?
One nice feature of ASSIST (from what I remember, its been a while) was that I could add in more perturbers and crank up the gravitational harmonics if I wanted to. It sounds like you support that too at least for perturbers?
Final edits of a paper at the moment, aim to submit next week. Perturbers are easy to add, though a little poorly documented at the moment. Additional physics right now are J2 of jupiter/sun/earth, and GR corrections for the sun and jupiter.
Biggest speed gain is that I have a custom SPICE reader that is multi-core friendly (I re-implemented a lot of the SPICE standard in rust), and it is used as the source for planet positions. Being able to skip planet integration leads to massive speedups.
How does Kete differ from REBOUND? (https://rebound.readthedocs.io/en/latest/)
Different goals, kete is meant to be aimed more toward observers and telescope data processing, all asteroids and comets at once on a laptop. Short term analysis (<100 years) and speed are the priority.
Is there a rule of thumb speed where an object is considered not from this solar system?
Eccentricity!
You can approximate the orbits of basically everything in the solar system using 2-body mechanics (IE, ignore the planets). If you do this you get orbits which are elliptical (eccentricity <1), parabolic (eccentricity = 1), or hyperbolic (eccentricity>1).
If the object has an eccentricity above 1, its not bound to the solar system.
Many long period comets have eccentricity hovering near 1, often these long period comets will be on their first pass (sometimes only pass) through the solar system. These comets though usually dont get much above eccentricity of 1. The 3 interstellars we have spotted have had like 1.2 or bigger. This one is above eccentricity 6! Its moving fast.
Edit: I have heard that when the first interstellar was found it actually broke a lot of peoples code, as it was common to hard code limits to allowed eccentricities (or simply not support ecc>1 at all).
This thing actually crashed our observatory software because we were trying to calculate position at too far of time horizons where because of the eccentricity the algorithms would not converge… that sucked but has been fixed. Ready for the next one!
> often these long period comets will be on their first pass (sometimes only pass) through the solar system.
Only pass because of the eccentricity, or for some other reason?
Oort cloud comets are so distant that they are only weakly gravitationally bound to the solar system. When they come in and we see them, they have enough energy to go back out to the extreme distances. Minor nudges from the big planets are enough to cause them to become ejected from the solar system (ecc>1). This can lead to the whole "one and done" thing.
https://en.wikipedia.org/wiki/Escape_velocity#Calculation
(assuming it hasn't interacted significantly with any other object in the solar system besides the sun)
you lucky so and so
many things are labeled historic, though some very very tiny number will actualy retain the power to inspire as this event will we have all dreamed of going into space to discover whatever is there, but as it turns out these interstelar objects are bringing us the only real physical evidence that we will ever get a good look at
On a similar vein there's Project Lyra which is a theoretical fly-by mission of ʻOumuamua or 2I/Borisov. The proposed trajectories to catch up are pretty crazy with my favorite being the 2030 launch for a 2052 fly-by that uses Jupiter and a close Sol 10 solar radii!) gravity assist to rocket out of the solar system [0].
It will be interesting to see if we've just been missing these extra solar objects. I have doubts we'll actually do a project Lyra style fly-by though. Funding is going the opposite direction and all.
[0] http://orbitsimulator.com/BA/lyra.gif and https://i4is.org/project-lyra-a-solar-oberth-at-10-solar-rad...
I'd expect this is just the lamppost effect and we'll start seeing lots of these. It means there's no great need to chase any particular one of them, we can almost certainly wait until we're ready, then pick one that is convenient at the time.
It also means that "Oumuamua is an alien craft!" will almost certainly join in the ignoble legacy of "thinking the first instance of a new thing must be ALIENS" once we've detected hundreds of these (or more, depending on how sensitive we can get). You'd really think we'd be over this by now, but apparently not.
Please correct me if I'm wrong, but my understand of the alien craft theory specifically for Oumuamua wasn't just because the object itself was new, but that it changed acceleration [1] without apparent off gassing in a way that isn't explained by our current understanding of orbital physics for a natural object.
It's not just "New object, must be aliens!" It's "This thing doesn't fit our understanding of orbital motion for natural objects, aliens is actually a rational, if still unlikely, possible explanation."
[1] https://en.wikipedia.org/wiki/1I/%CA%BBOumuamua#Non-gravitat...
There were a number of anomalous characteristics including its shape, acceleration, rotation, origin, and reflectivity.
How do we know they're anomalous characteristics if it's literally the first one we've ever spotted? What is the normal shape of an interstellar comet core?
The same as the ones from this system. Borisov had the same characteristics.
> The same as the ones from this system.
Why would we assume non-interstellar comets are always the same as interstellar comets? Conditions obviously are a little different when something is ejected from a system and then spends millions of years in interstellar space.
> Borisov had the same characteristics.
We have a sample size of three thus far. Making conclusions right now is like saying all extrasolar planets are large gas giants because the first three were.
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We'd assume most interstellar objects are comets because that's which objects you find on the outskirts of a solar system and are the easiest to get kicked out. We'd assume they're mostly like our comets due to the Copernican principle. We shouldn't assume we're special.
> We'd assume they're mostly like our comets due to the Copernican principle.
We're still figuring out what our comets are like, let alone unusual ones spending a few million years in interstellar space. New types of comets(ish) bodies discovered in the 2000s:
https://en.wikipedia.org/wiki/Active_asteroid
https://en.wikipedia.org/wiki/Manx_comet
We've spotted ~5k out of an estimated trillion. Each one we've sent a probe to has brought surprises. The Oort cloud remains theoretical at this time, and the first Kuiper belt object other than Pluto/Charon was found in 1992. It would be deeply silly to think we know everything about our local comets, let alone unusual ones from elsewhere.
For example, being flat like a pancake is obviously highly unusual and very different from anything we have seen from stellar comets.
Stellar comets haven't been ejected from another solar system. We have vanishingly few examples of those, and we've not directly observed any up close.
"Flat as a pancake" is one of several theoretical possibilities from its light curve, not a known fact about the object.
"Highly unusual" in space tends to mean "there are a bunch, but we haven't seen them until now". In 1992, exoplanets were "highly unusual". Now they're everywhere.
The highly unusual properties are such that they are genuinely hard to explain for astronomers. See my neighbouring comment.
Yes (a change in acceleration was reported), but even in the link you yourself provide the hypotheses are framed within standard physics, not alien technology.
The latter got more than its fair share of press because Harvard's Avi Loeb proposed it as potential evidence of ET.
He later claimed more evidence from potential spaceship bits he reckons he found from an ancient meteor, and seems to specialize in these sorts of claims. [1]
Like you say, not irrational but perhaps over-hyped by people who ought to know better...
[1]https://www.independent.co.uk/news/world/americas/avi-loeb-i...
The history of science is that every freaking time we look somewhere new, we find something new. It happens over, and over, and over, and over again. We have a really bad track record of predicting things in advance in new domains. The exceptions are leaping to your mind precisely because you've heard about them because they're the exceptions.
Also, to date, zero of those things have been "aliens".
So rushing to declare the first instance of what was completely obviously a new class of objects as "aliens" because it didn't behave like what we expected is not rational, because we should expect that new things don't behave like we expect. The odds that the first one of these we detect is also the one from aliens is just not a good bet.
I'd bet a tidy sum of money that in 25 years it'll simply be common knowledge that these class of objects sometimes have those characteristics because of some characteristic special to them. Probably something to do with having a lot of things that turn to gasses and exert accelerations on the object because they were never blown off by the solar wind or something because of them being in deep space for millions of years. Might be most of them, might be a small-but-respectable fraction, but I bet in hindsight this is recorded in the history books right next to "pulsars are alien beacons!" and with the exact same tone of lightly sneering contempt we hold for that now. To which I can only say to the future, let the record show we did not all think it was aliens.
If we ever stop being excited about the possibility that poorly understood phenomena are evidence of undiscovered intelligent life the we'll have lost a part of our humanity.
That's just bullshit. The idea that undiscovered intelligent life is a plausible explanation for such things is just the triumph of numerically illiterate wishful thinking over rational thought.
I'm not saying that it's a conclusion that we should jump to. Just that it's silly to expect people not to consider it first. It's more related to why we're looking up in the first place than any of its alternatives.
It's so ridiculous that the only reason to expend a single keystroke on it is to demolish it.
Consider what the implication would be if these are ET spacecraft. The galaxy would be absolute soaked in ETI. The Fermi argument would then bite maximally: why did we even evolve, if the galaxy has been so saturated? Why wasn't every single planet and asteroid used for colonies and resources ages ago?
It's important to realize that science fictional tropes of galaxies with everyone zooming around in spaceships having adventures are not consistent with what we observe.
What does the low probability have to do with it?
If you had asked Galileo's contemporaries about the probability that he'd find moons orbiting Jupiter, they'd have put it at zero, and they turned out to be wrong.
Einstein's work was also in flagrant disregard of the established scientific sensibilities of the time.
I can't speak for everybody, but the excitement that I get when I look through a telescope, or a microscope, or commune with any machine that can see something that I can't... it comes from the possibility that I'll see something impossible, something that invalidates the theories which previously governed what I'm likely to see. It's why we keep building better telescopes and bigger particle colliders--because we want to prove ourselves wrong.
It's fine to be a rationalist with an appreciation for existing theory, but it's not irrationality when others attempt to invalidate what you're protecting--thats where progress comes from. We wouldn't know as much as we do without the people who look for things that shouldn't be there on the basis of viewpoints outside of accepted theory.
I remember the first time I heard of that pattern of thinking. My initial reaction was "OMG, it must be aliens!"
Then I thought "now wait a minute...hold on..."
It's not so much a matter of being ready, it's a matter of what planets are where that we can get a boost out of to get those speeds. Even with a fleet of working starships and assembling something in orbit getting up the to speed of these extra solar objects practically requires some intense maneuvers near conveniently positioned and timed planets.
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> It also means that
No, it doesn't mean that. What makes 'Oumuamua special is not the fact that we didn't see interstellar objects before. It's rather the fact that 'Oumuamua has highly unusual and hard to explain properties. Avi Loeb:
> ‘Oumuamua exhibited a non-gravitational acceleration of 4.92 ± 0.16 × 10^⁻6 m/s² that decreased proportionally to 1/r², where r represents the heliocentric distance, corresponding to a formal ~30 σ detection of non-gravitational acceleration (Micheli et al., 2018). The inverse-square relationship typically indicates radiation pressure or outgassing forces. However, despite extensive observations by the Spitzer Space Telescope, no carbon-based molecules, dust, or thermal emission indicative of cometary outgassing were detected (Trilling et al., 2018). Such a paradox — acceleration without observable mass loss — violates fundamental assumptions about how small bodies behave in the solar system.
> The object’s extreme geometry presented another unprecedented observation. ‘Oumuamua’s brightness varied by a factor of 10 during its 8-hour rotation period, indicating an extreme geometry with an aspect ratio exceeding 10:1 (Drahus et al., 2018; Meech et al., 2017). Such extreme elongation is unprecedented among known Solar System objects, leading to competing interpretations of either a cigar-shaped or pancake-like geometry (Belton et al., 2018; Luu et al., 2020; Mashchenko, 2019; Moro-Martín, 2019a,b; Zhang & Lin, 2020).
> More significantly, ‘Oumuamua entered the Solar System with a velocity remarkably close to the Local Standard of Rest (LSR). The object’s velocity before encountering the Solar System was within approximately 6 km/s of the local median stellar velocity and just 11 km/s from the LSR, with negligible radial and vertical Galactic motion (Mamajek, 2017). Fewer than 1 in 500 stars share such kinematics, making ‘Oumuamua’s near-stationary approach highly improbable for a naturally ejected object from a nearby star system (Loeb, 2022). Natural ejection mechanisms from planetary systems typically impart the host star’s peculiar velocity to expelled bodies, yet ‘Oumuamua appeared to originate from the most kinematically common frame of reference in our Galactic neighborhood (Loeb, 2022; Mamajek, 2017).
> The object’s rotational dynamics added another layer of complexity. ‘Oumuamua displayed non-principal axis rotation, exhibiting a tumbling motion rather than spinning around a single axis. Such a rotational state is unusual for an object that has been traveling through interstellar space for potentially billions of years, as collisions and internal friction should have damped its motion to simple rotation (Belton et al., 2018; Fraser et al., 2018).
> Finally, the object’s slightly red color differed from both typical comets and asteroids. Its spectral properties showed no absorption features that would indicate specific mineral compositions, making it difficult to determine its definite surface composition (Jewitt et al., 2017; Ye et al., 2017). This spectral ambiguity prevented researchers from determining surface composition through standard techniques, leaving the object’s fundamental nature — rocky, icy, or something else entirely — unresolved.
https://avi-loeb.medium.com/scientific-paradigm-resistance-e...
Avi Loeb got trucks mixed up with aliens, then proudly announced he'd found a chunk of alien metal in the ocean based on that mistake.
https://news.climate.columbia.edu/2024/04/09/was-it-an-alien...
> The signals consisted of so-called Rayleigh waves, high-frequency motions that travel on or just under the surface, and die out quickly as they radiate from their source. These can be generated by earthquakes, but also by human activities, including explosions, electrical signals and vehicles. The sources of these ones seemed to be moving, not stationary. Moreover, they appeared in a definite pattern: several per hour, almost invariably between 5am and 11pm local time.
> The team checked a Google Earth map showing the seismometer and its environs. It was just off the main road to the harbor, near the Manus Navy Health Center. The center seemed to be a locus of activity, with the signals moving back and forth from it, southwest to north―the same orientation as the road. Ekström’s conclusion: the seismicity was coming from trucks bumping along the irregular surface of the road, mostly in daytime, stopping at the health center to deliver or pick up people or supplies, then going back where they came from. That included the purported tremor from the meteor explosion.
https://www.independent.co.uk/news/world/americas/avi-loeb-i...
"Fewer than 1 in 500 stars share such kinematics" means 200+ million in our little galaxy alone.
Solar Oberth manuever FTW! :D
The High Frontier board game from Phil Eklund even has it as a valid option on its orbital map of the Solar system. :)
Rendezvous with one of these would be a good use for a NERVA-type nuclear engine (upper stage, not used in the atmosphere).
Also seems like the thing to do, given that we are finding more than one of these now, is to build such a thing and have it on standby and look for one that's inbound so we can launch at the best window to reach it.
to build a thing would be astonishingly lucky for it be parked in the right place to catch the next one, so where would you park it? seems like it would be better to build a lot of them, and park them through out in various orbits so maybe one of them has a chance to rendezvous
Even with a NERVA engine it's a LOT of work to get to the 26 kmps of an object like ʻOumuamua so you're still at the mercy of planets being in roughly the right locations to provide some gravity assists. I think it would widen the workable solutions but something like the 10 SR assist could work with things we've actually built already.
With Vera Rubin's Large Synoptic Survey Telescope coming online, we'll likely see many more of these. It seems like it would be very difficult to physically intercept any large percentage; what is the next best alternative to physical interception? Lasers? Masers? Comet trail sampling? Pre-staged interceptors?(Interstellar Interloper Interceptor? I'd be interested in entertaining the possibility)
"We are Engineers at the Vera Rubin Observatory, Ask Us Anything!" https://old.reddit.com/r/space/comments/1lwgfre/we_are_engin...
Vera Rubin isn't even giving us data dumps yet. It's going to be like a veritable firehose of interstellar object detections. Should be a wild time for the field.
The Wikipedia article [0] has a nice animation [1] of the trajectory through the inner solar system, sourced from this [2] 3D interactive viewer (press “Plot Object” and then drag the slider below “Change Time Speed”).
[0] https://en.wikipedia.org/wiki/3I/ATLAS
[1] https://en.wikipedia.org/wiki/3I/ATLAS#/media/File%3A3I_ATLA...
The designation 3I means the third interstellar object discovered. 1I (Oumuamua) was discovered in 2017, and the new Vera Rubin telescope is likely to discover a lot more in the future.
We're just at the beginning of finding this new population of objects, and I think it's very exciting. It's like when Ceres was first discovered (in 1801) and suddenly people found a whole population of asteroids between Mars and Jupiter. We're in a similar time now with interstellar objects.
How many interstellar objects pass through the Solar System each year? How many will we find in the next 10 years? We're about to find out.
I hope this will end better than in Outer Wilds.
LMAO. That was the exact immediate reaction I had as well. The outer wilds brain rot is truly inescapable.
I often wonder what would it take to have a rocket capable of launching a pre-packaged probe to intercept such objects. What would it look like? An SLS with a cubesat on top?
Sixty Symbols has a nice overview video on 3I/ATLAS:
My mind is boggled at the speed with which an object that size is travelling.
Amazing.
This object has quite the hyperbolic excess. There's no doubt it's not a solar system object.
