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A Star Grazed Our Solar System 70,000 Years Ago, Early Humans Likely Saw It (space.com)

Posted by BeauHD on from the blast-from-the-past dept.

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.

4 of 164 comments (clear)

  1. Sigh. by ledow · · Score: 3, Insightful

    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.

    1. Re: Sigh. by Anonymous Coward · · Score: 2, Insightful

      I'd prefer to trust a professional in the field than an AC.

  2. A star a light year away by Opportunist · · Score: 1, Insightful

    Let's be sensible here. We are talking about a very faint star, faint enough that we didn't bother to or even couldn't measure its path until now. Passing our solar system at the distance of a light year. Remember the "family portrait" Voyager took? Now, that's about 19 lightHOURS out. Or roughly 500 times closer.

    Do you really think a human 70,000 years ago without any astronomic tools would have noticed? Or even cared?

    --
    We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
    1. Re:A star a light year away by ledow · · Score: 5, Insightful

      Some beetles navigate by the Milky Way.

      Ancient cultures all named thousands of stars and gave them associated legends, as well as navigated by them. They knew about comets, meteors, stars and galaxies.

      To be honest, they were more likely to notice something unusual - especially if it moved over time - than the average person would be today. The naked eye doesn't pick up much in a city nowadays.

      You know how I got into astronomy at age 30? I saw Venus for the very first time, while driving to Scotland for 9 hours.

      A culture that revolves around day-time and can't do anything of an evening because of insufficient light, yet being a species that naturally wakes up throughout the night - they're going to spot a red star going across the sky just like they could spot Venus doing so. And it would be a "Oh, look, that's unusual" rather than "ARGH! We're all gonna die!" purely because it wouldn't actually be that unusual or interesting to them, given the size and brightness of said star in the sky.