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A Star Grazed Our Solar System 70,000 Years Ago, Early Humans Likely Saw It (space.com)
schwit1 shares a report from Space.com: Some distant objects in our solar system bear the gravitational imprint of a small star's close flyby 70,000 years ago, when modern humans were already walking the Earth, a new study suggests. In 2015, a team of researchers announced that a red dwarf called Scholzs star apparently grazed the solar system 70,000 years ago, coming closer than 1 light-year to the sun. For perspective, the suns nearest stellar neighbor these days, Proxima Centauri, lies about 4.2 light-years away. The astronomers came to this conclusion by measuring the motion and velocity of Scholzs star -- which zooms through space with a smaller companion, a brown dwarf or "failed star" -- and extrapolating backward in time. Scholz's star passed by the solar system at a time when early humans and Neanderthals shared the Earth. The star likely appeared as a faint reddish light to anyone looking up at the time, researchers with the new study said. The study has been published in the journal Monthly Notices of the Royal Astronomical Society: Letters.
1 light-year is 63,241 AU.
An AU is the distance from the Earth to the Sun.
The solar system is about 40AU (depending on your definition of planet).
So "close" is really... well, testing things a bit. Astronomically, yes, very close.
Practically? It's 20,000 times the size of the entire solar system away and to my knowledge only two objects have ever left the solar system.
Chronologically? It happened 70,000 years ago which, again, is tiny in astronomical terms but it's already long gone. We could do nothing about it in a reasonable time, we'd barely be able to study it, and if it was slightly to the left we'd all be interstellar dust (again) by now.
Though interesting, it's hardly close or anything we can really utilise or study,
I'd be more worried along the lines of "chances are something else could come and go this and wipe us out and likely we'd never know it was going to happen". Not just stray asteriods (which obviously would be knocked for six by something like this straying close) but an entire damn star. That's solar-system-ending.
The solar system is way bigger than 40 AU. The Oort cloud is part of the solar system and it extends to about 3 light years. So, the solar system extends, at least, to 3 light years. Not to mention, the sun's magnetic bubbles extend that far. I'm not sure why you stopped at the last planet and not include the Kuiper Belt and Oort Cloud as part of the solar system.
Read the first link in the summary, or even just the first sentence in the quote.
This isn't just some theoretical perturbation. We have quite the catalog of objects with hyperbolic orbits, and their points of origin is rather clumpy instead of randomly spread out across the soy or even a plane. The clumps suggest specific events that caused changes in distant orbits.
We've known this star got close in the past for some time, the news is that someone showed that there is a category of these objects that matches the effects expected from the location and timing of the star, basically connecting the dots with some work.
That is the exact opposite of your claim that this only affects hypothetical objects not observed, which should have been obvious if you did read and comprehend the summary.