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Comment by parksy | Hacker News Reader

Perhaps we could "shotgun" a swarm of tiny cubic reflectors, literally just use a controlled explosion to scatter them through the solar system, then track their movements to spot hidden objects. Some may even be drawn in and attach to otherwise dark objects by gravity, allowing them to be more easily tracked.

I'm guessing the issue with that other than the technical challenge would be filling space with too much noise?

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Space is really big. You'd need a very large number of tiny reflectors to have a decent chance of any passing close enough to unknown objects to be measurably affected by their gravity.

My intuition would be that there'd be sort of a "birthday paradox" situation at play; if you had a lot of satellites that most of the time aren't close enough to random objects to detect them, eventually as they follow their orbital paths eventually there'll be a high probability that any random asteroid will at some point get close enough to one of them to detect. Maybe you'd be able to say things like "if an asteroid has a mass of a million kilograms and spends most of its time in the inner solar system, then our odds of detecting it within a hundred years is 70%."

Initially, all the unknown, undetected massive objects would contribute background noise that would make small objects harder to find. But as you detect and classify them, they can be accounted for, and then the smaller objects get easier to detect. Then in the end I guess it's a matter of how complete of a catalog of objects can you maintain and simulate, and how precise are the time and distance measurements used to detect gravitational perturbances.

And yeah, given that space is big you'd really want to deploy a ludicrous number of these things if you really want to build a solar-system wide detection network that could spot large-ish interstellar objects as soon as they enter the system, or detect a stealth-material coated asteroid lobbed by some malefactor in a timely manner.

To keep track of every asteroid in the solar system, the first thing I'd do is put a tracker on each one of them, over a certain size.

With that done, maybe you don't even need separate man made probes.

Not sure how hard making and tracking those trackers would be.

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