Deceleration burn?
[0] https://en.wikipedia.org/wiki/C/2023_A3_(Tsuchinshan–ATLAS)
But that film is relevant to this comet in another way -- several missions that made it into space before the administration's war on the scientific enlightenment may be able to image the comet when we can't see it (perihelion) or when they're much closer to it than we'll ever be.
Astronomers discover 3I/ATLAS – Third interstellar object to visit Solar System (308 points, 26 days ago, 171 comments) https://news.ycombinator.com/item?id=44451329
Vera C. Rubin Observatory Observations of Interstellar Comet 3I/Atlas (3 points, 7 days ago) https://news.ycombinator.com/item?id=44638392
Feasibility of a Spacecraft Flyby with the Third Interstellar Object 3I/Atlas (3 points, 6 days ago) https://news.ycombinator.com/item?id=44649150
First Hubble telescope images of interstellar comet 3I/ATLAS (109 points, 6 days ago, 29 comments) https://news.ycombinator.com/item?id=44649653
Probably not ground-based eyes, but possibly Hubble.
i.e. "the inhabitants are scanning us"
We have all kinds of space radars though that are active.
It does have a great amount of mass, so you could rendezvous, construct a mass driver or ion drive and start taking it apart and using chunks of it as extra reaction mass. That would allow you to essentially get a free reaction mass "refill". You will still need a lot (a lot) of power, and solar will be near zero.
i mean aren't we talking like km/s of speed difference? idk of any kind of material even 50km long that could absorb that kind of stretch/sheering like that...
The voyager craft, which not only had very good acceleration early on (the best we could do, really), combined with exceptional gravity slingshots and a lot of time - and are by all accounts some of the fastest man made objects ever - are going 15.4 km/s and 17 km/s relative to the sun.
3I/ATLAS is going so much faster than these objects they might as well be stationary.
Even ignoring the limited amount of time we have to intercept, catching up to 3I/ATLAS would be incredibly difficult to do. Perhaps impossible with our current technology*. Like catching up to a semi-truck going full speed on a highway with a bicycle. After it’s already passed us and is a couple miles down the road.
*barring theoretical (and kind of insane and dangerous) tech like Orion drives.
Idea of gravity-assist acceleration, mechanically is just rotation of pair tightly tied bodies (and cut tie in right moment, so one body got acceleration and other got deceleration), but as it is impractical to tie for example to Moon with rope, used gravity force.
What also interesting, gravity-assist could use not only orbital speed of large body, but also got some acceleration from rotation of large body, as for gravitation, large planet is not just one material point, but system of few smaller (sub)bodies, and closer (sub)bodies give more acceleration than others.
Even better: you can forget the comet, accelerate, keep accelerating until there is no more power or even a working motor while also extending a big sail to let solar wind accelerate you a little more.
The whole thing would be like something like shooting a bullet at a moving target, but it's an idea.
That hypothetical probe will not look anything like any other space probe before it, but more like an artillery shell. (They can survive pretty damning Gs and still run that little embedded computer, so it's not a completely insane idea, I guess.)
We would also have to detect the interstaller object plenty in advance, so the probe can be launched "comfortably" in a trajectory which will intercept at exactly where the "object" is going to be.
Of course the G-load would lessen based on how much you sped up to match its speed beforehand, but still, I think you'd need to be pretty much sped up to near the same speed as it before you could remotely possibly survive the impact.
That leads to another idea - if something more substantial was placed in its path - the resulting debris and gas cloud from the impact could reveal something about the contents of the object.
Or, if it's an alien probe, it would force their hand. :-D We could see some exotic manuevering.
But they're probably used to it. At 61,000 m/s, 0.5mv^2 must turn every collision with a small rock into quite a big bang.
Of course your point is probably still valid.
NitpickLawyer•6mo ago
This is so cool! Vera Rubin is designed to detect lots and lots of similar things, and having a test case where they can go back and "track" 3I through data is probably a great thing for tuning their models. Can't wait to see what Rubin finds over the years.
Also, it's so cool that they found 3I pretty early, we'll now have lots and lots of data from multiple powerful observatories and probably from some remote ones as well. It's nuts that we'll probably get some images/data from probes out in the solar system (mars orbiters, maybe JUICE).