3I/ATLAS: Third Interstellar Visitor

A third interstellar object has entered our star system, and it is being called 31/ATLAS. I was pondering how long it would be before Earthlings can mine these rocks for gold, silver, and other elements of the universe. I asked ChatGPT when we might be able to do that, and this was its answer:

“Interstellar objects like 3I/ATLAS are coming in fast, tens of kilometers per second. They’re usually discovered months before closest approach, sometimes only weeks. By the time we spot them, designing, building, and launching a mission to intercept them or mine them is basically impossible with today’s technology.

To mine a comet like 3I/ATLAS, you’d need an intercept mission (catching it while it’s moving really fast). Anchoring gear to keep from being blasted off by sublimating jets. Extraction tech that can handle low-gravity ice/dust mixtures. We don’t have that ready yet, but projects like ESA’s Comet Interceptor (launching 2029) are a baby step toward a spacecraft that waits in orbit, then darts out to chase the next interstellar visitor.

Comets are rich in water ice, carbon compounds, and sometimes nickel, iron, or silicates. Water = rocket fuel (once split into hydrogen + oxygen). Metals = structural materials. If you could capture one, it’s basically a gas station and hardware store in space. Mining 3I/ATLAS itself? No. It’s already inbound, and by the time anyone’s hardware can reach it, it’ll be gone. Mining comets in general? Plausible in the mid-to-late 21st century. Companies like Planetary Resources and Deep Space Industries had plans, but funding fizzled.

The first real shot might be at a local comet or near-Earth asteroid, not a once-in-a-lifetime interstellar visitor. We can’t mine 3I/ATLAS, not yet. But the concept of harvesting comets for resources is one of the most practical long-term strategies for building a spacefaring civilization. Want me to sketch out what an ideal “comet mining mission would look like, if money and launch timing weren’t a problem?

When 1I/‘Oumuamua passed through in 2017, it behaved oddly. It had no visible coma like a comet, but it still accelerated slightly as if something was pushing it. That led some (famously Avi Loeb at Harvard) to float the idea it might be an alien probe using light-sail physics. The mainstream explanation is more mundane and says outgassing of frozen hydrogen or carbon monoxide gave it a tiny thrust, but so evenly spread we couldn’t see a tail.

With 3I/ATLAS, astronomers have already seen a clear coma and tail. That means it’s definitely venting gases like a “normal” comet. It’s on a pure hyperbolic trajectory, inbound, swing past the Sun, outbound, no braking, no course changes. In other words, it’s not doing anything that suggests artificial propulsion or slowing down to park near us.

Interstellar objects don’t have a reason to stop unless acted on by gravity or propulsion. The Sun’s pull speeds them up as they fall in, then they coast out just as fast. For 3I/ATLAS, we’re talking tens of km per second, way beyond any slowing that random sublimation could explain. So, no, 3I/ATLAS isn’t going to do an ‘Oumuamua-style mystery wiggle that sets off the “spaceship?” headlines. It’s already behaving like a classic comet, just one born in another star system.

That’s the big mystery with 3I/ATLAS (the third known interstellar object). We know it’s not from our solar system, its orbit is hyperbolic, meaning it’s just passing through and will never loop back around the Sun. But astronomers can’t yet pin down its home star system. It entered the solar system from the general area of the constellation Lupus (near Scorpius and Centaurus). That gives us a vector, but not a precise origin.

It’s moving so fast (tens of kilometers per second) that it’s not gravitationally bound to the Sun. That confirms it came from outside. With ‘Oumuamua (2017), astronomers traced its inbound path and suggested possible origins near the Lyra constellation, but even then, they couldn’t name a definite parent star. Same problem here, too many variables and uncertainties.

Stars themselves are moving around the galaxy. By the time a comet like 3I/ATLAS arrives, its parent system may be in a completely different part of the sky than when the comet was ejected. Without extremely precise velocity data and a long observational arc, we can’t run the orbital clock backward with enough certainty to land on a specific system.

So, we don’t know its star system of origin. The best we can say is it likely came from another planetary system in the Milky Way, got kicked out (maybe by a giant planet’s gravity), and wandered for millions of years before crossing paths with us. Some scientists say each of these interstellar visitors is basically a postcard from another solar system’s construction site.”

C. Rich

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