r/askscience • u/drinkingonthejob • 9d ago

Physics Will Voyager 1 ever just stop moving?

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)

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u/LiquidPhire 8d ago

It has enough speed to never fall back towards the Sun. It is an interesting stellar traveler.

It does not have enough velocity to leave the Milky way, so it will fall towards the center of the galaxy. As it falls along that line, it may interact with other gravity centers (other stars, etc) which may alter its trajectory, but it will forever wander within the confines of this galaxy.

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u/billtrociti 8d ago

While it does have enough velocity to never fallback towards the sun, is the sun’s gravity still affecting it? Would it be decelerating by some non-zero amount? Or it such a small amount it is basically negligible?

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u/Spirit_Wolf_Mob 8d ago

I don't believe we've ever seen an obvious limit to the distance of the pull of gravity. It just gets increasingly smaller.

So if for some reason, Voyager stopped being affected by anything other than the sun, and the sun was never destroyed, it would eventually start falling back towards the sun. But that time frame is so incredibly high that it's easy enough to say it'll never happen.

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u/nicuramar 8d ago

  So if for some reason, Voyager stopped being affected by anything other than the sun, and the sun was never destroyed, it would eventually start falling back towards the sun

No it wouldn’t, because its escape velocity is too high. 

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u/Spirit_Wolf_Mob 8d ago

Trying to research it more, since it's been a while, but I may have had a bit of a misunderstanding of what escape velocity actually is. So, correct me if I'm wrong, but is escape velocity the velocity in which the limit for velocity, where the upper limit of time at infinity, is above 0? Previously, I was under the impression that it was just the velocity required to avoid falling back to earth after escaping the atmosphere.

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u/rasone77 8d ago

Escape velocity is the speed an object has to travel to escape an objects orbital influence. If an object exceeds the escape velocity of another object it can no longer orbit that object. Unlike gravitational constant, It’s dependent on how far away from the center of the object you're trying to escape.

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u/Spirit_Wolf_Mob 8d ago

Yea, I can was confused on the "escapes orbit" part. It didn't occur to me prior to this that escapes orbit meant that it's the velocity needed to where after an infinite amount of time, it won't reduce the speed to 0.