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Comment by TeMPOraL | Hacker News Reader

> So, the reason I asked was because of not having a source. Did this come from SpaceX or someone authoritative who has done the math?

SpaceX said that wrt. their original projected trajectory of a Mars Transfer Orbit. Since right now we're talking about something more like Ceres Transfer Orbit, the projection can change (and, as per article, astronomers are asking Elon for details to calculate it), but keep in mind one thing: space is big and empty. The chance of it hitting anything on short timescales are close to 0.

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> SpaceX said that wrt. their original projected trajectory of a Mars Transfer Orbit. Since right now we're talking about something more like Ceres Transfer Orbit, the projection can change (and, as per article, astronomers are asking Elon for details to calculate it), but keep in mind one thing: space is big and empty. The chance of it hitting anything on short timescales are close to 0.

But one of the reasons I asked was not because I was worried about whether it would hit something on a short timescale (even though there is a non-zero chance it could happen). I'm aware of the vastness of space.

I was curious about what happens over 10, 10^3, 10^9, 10^12, 10^100 orbits later.

The answer is: over 10 orbits - no. Over 10^3 orbits - no. Over 10^9 and more - nobody really cares. By that time the Sun will be halfway to going cold.

Your answers seem to be about whether or not there will be a collision at those time points.

My curiosity is about visualizing the orbit over time (which includes a non-zero possibility of collision).

P.S. I doubt you would disagree that speculating about where the Roadster will be when the Sun will be getting colder is fun, and not 'nobody really cares.'

Of course, such simulators are hard and expensive and mostly approximations, but doesn't hurt to ask about what options are out there.

On time scales that large the exact orbit is unpredictable, see the Pioneer Anomaly [0] where the RTGs heat radiating away provides a tiny but non zero deceleration, over huge time spans even tiny forces add up. On top of that it's going to be slightly perturbed by Earth, Mars, and Jupiter in ways that can only really be modeled not solved explicitly.

I give it less than a hundred orbits until someone takes a rocket over and nicks it.

> but keep in mind one thing: space is big and empty.

While this is on average true (i.e. including interstellar space) , it doesn't apply to an orbit within the solar system with large AU orbits: Jupiter's massive gravitational field will make the Tesla's orbit unstable.

> The chance of it hitting anything on short timescales are close to 0.

There's no way of knowing this without calculating and modeling the trajectory, but SpaceX is not publicly providing this information. I understand the potential for bad PR from clickbait headlines like "Tesla to crash into Earth in 2052"* (*according to a Ugandan teen space enthusiast/prodigy, modelling in KSP)

It doesn't matter if it's unstable - as long as it was not carefully aimed to hit something, "space is big and empty" means that a random unstable orbit is exceedingly likely not to hit anything for a very, very, very long time.

There's no way of knowing this without calculating and modeling the trajectory, but you can still be 99.99% sure that it's not going to hit anything for thousands or even millions of years even without extra information. As the parent poster said, the chance is close to 0.

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