First, in case you haven’t heard: 70,000 Years Ago, Another Star Flew by the Edge of the Solar System | RealClearScience.
According to an international team of astronomers, about 70,000 years ago a red dwarf star — nicknamed “Scholz’s star” for the astronomer who discovered it — passed by our solar system just 0.8 light years distant. In fact, 98% of the 10,000 simulations the team ran projected that the star’s path grazed the outer edges of the Oort Cloud, a region of space filled with icy planetesimals which marks the final boundary of our solar system.
…Scholz’s star is now twenty light years away and won’t be returning anytime soon. However, Dr. Coryn Bailer-Jones of the Max Planck Institute for Astronomy calculates that we may receive another visitor in the distant future. Last December, Baller-Jones reported that the rogue star HIP 85605 may pass as close as .132 light years to the solar system between 240,000 and 470,000 years from now. That’s a close miss on the cosmic scale, but more than far enough that our futuristic ancestors will have little to worry about. The only concern would be that HIP 85605’s foray through the inner Oort Cloud might send a few comets careening in Earth’s direction.
This is interesting and just goes to show that, on a large enough time scale, assuming we don’t drive ourselves extinct, humanity will eventually be able to go to the stars, even if we have to wait for other stars to occasionally come near us. (Not that we could make such a trip with current technology, but it’s a lot easier than reaching the nearest current star.)
That said, it’s important to keep in mind what “near” means in this context since some news outlets are saying the star passed “within” our solar system, implying to most people that it passed near the planets or something. As Pomeroy notes, this pass was 0.8 light years away. While it’s less than a fifth the distance to the current nearest star (Proxima Centauri), that’s still over seven trillion kilometers, over 52,000 times the distance between the Earth and the Sun, or more than 1300 times the distance to Pluto. Even the star HIP 85605 mentioned above that might some day pass as close as 0.132 light years away will still be more than 200 times the distance of Pluto.
Saying that these near passes are within our solar system is only accurate if your consider the solar system to encompass the theoretical Oort Cloud, thought to be a cloud of icy rocks that extends as far as 2 light years away, or half the distance to the next nearest star. While some might argue that the phrase is accurate, it’s a far broader meaning of “solar system” than most people are familiar with.
It also illustrates that, as large as the solar system is, and it is incomprehensibly large by any human scales, it’s essentially the outer layers of the Sun when seen from interstellar distances.
Space is big. Really big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space.