So, what exactly is going to happen to that Tesla that Elon Musk shot into space?
It's going to wander around the solar system, sure. But there are planets and gravity and stuff, so what are the odds of it eventually slamming into something?
Small, but not zero — according to this fun analysis by a group of astrophysicists! They modeled the Telsa's current trajectory and estimated that there's a mid-to-low-single-digit chance that it hits Earth or Venus over the next million years:
The orbital evolution is initially dominated by close encounters with the Earth. The first close encounter with the Earth will occur in 2091. The repeated encounters lead to a random walk that eventually causes close encounters with other terrestrial planets and the Sun. Long-term integrations become highly sensitive to the initial conditions after several such close encounters. By running a large ensemble of simulations with slightly perturbed initial conditions, we estimate the probability of a collision with Earth and Venus over the next one million years to be 6% and 2.5%, respectively. We estimate the dynamical lifetime of the Tesla to be a few tens of millions of years.