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Astronomers race to study interstellar interloper

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126 points bikenaga | 5 comments | 11 Jul 25 15:43 UTC | HN request time: 0s | source
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rtkwe ◴[11 Jul 25 17:11 UTC] No.44534650[source]▶
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...

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jerf ◴[11 Jul 25 17:47 UTC] No.44535076[source]▶
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.

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dbingham ◴[11 Jul 25 18:10 UTC] No.44535302[source]▶
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...

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ryanblakeley ◴[11 Jul 25 18:20 UTC] No.44535408[source]▶
There were a number of anomalous characteristics including its shape, acceleration, rotation, origin, and reflectivity.
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ceejayoz ◴[11 Jul 25 19:08 UTC] No.44535849{3}[source]▶
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?
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1. TheBlight ◴[11 Jul 25 21:33 UTC] No.44536976{4}[source]▶
The same as the ones from this system. Borisov had the same characteristics.
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2. ceejayoz ◴[11 Jul 25 21:39 UTC] No.44537021[source]▶
> 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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3. TheBlight ◴[11 Jul 25 23:29 UTC] No.44537861[source]▶
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.
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4. ◴[11 Jul 25 23:41 UTC] No.44537929[source]▶
5. ceejayoz ◴[12 Jul 25 00:30 UTC] No.44538199{3}[source]▶
> 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.