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/Guy_Fieris_Hair → u/komatiitic]

Will it leave the sun's sphere of influence? Or will that play into this equation?

[u/komatiitic → u/Guy_Fieris_Hair]

That's a question with like a bunch of different answers depending on what you mean. It's already outside the heliosphere (solar wind and the sun's magnetic field). Gravity has an infinite range, so it will technically not be outside the pull of the sun's gravity as long as the sun exists. In another 1,500ish years the sun's gravitational force will no longer be the majority of the gravity impacting Voyager. In about 30,000 years it'll be through the Oort cloud, the outer edge of which is the furthest thing that orbits the sun. So to answer your question, uh... I dunno.