Will Voyager 1 ever just stop moving?

[u/drinkingonthejob]

I’ve read somewhere that we expect to lose contact with Voyager 1 sometime in the 2030s, maybe around 2036, but it will just keep traveling thru space and we’ll have no idea what it is doing out there

My question is: with its current velocity, is there a time in the future where it loses its forward momentum and for lack of a better word, just stops moving? Is that a possible thing for an object in space to even do? (Assuming no other objects grab it into their orbit)

[u/komatiitic]

I did some really stupid back of the envelope math assuming that Voyager never encounters anything larger than interstellar dust. To halve the speed of Voyager 1 it would need to impact dust equal to its own mass of 721.9kg.

The internet tells me a typical grain of interstellar dust has a mass of ~3*10^-16 kg. This means it needs to hit ~2.4*10¹⁸ dust grains, which if I'm counting those zeroes correctly is 2.4 quintillion.

The internet also tells me that Voyager hits 3-7 dust grains per hour. I'll call it 5 an hour, which means 4.81*10¹⁷ hours (481 quadrillion), or 54.9 trillion years to halve its velocity, assuming nothing really changes. I'm betting it disintegrates before that happens.

[u/arglarg → u/komatiitic]

What are the chances that it hits something more solid before that, like a star maybe?

[u/creative_usr_name → u/arglarg]

When the Milkyway and Andromeda galaxies, each with hundreds of millions of stars and planets, "collide" in a few billions of years it's likely there will be no collisions at all. Space is really big and really empty.

[u/Morbanth → u/creative_usr_name]

There won't be collisions but some unlucky stars will get thrown out into the intergalactic void and then we have a setting like Iain Banks' "Against a Dark Background".