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Another Star Passed Through Our Oort Cloud 70,000 Years Ago

Posted by Soulskill on from the thanks-for-not-hitting-us dept.

New submitter mrthoughtful writes: According to researchers at the University of Rochester, a recently discovered dim star (Scholz's star) passed through our Oort cloud 70,000 years ago. At its closest, it was about 52,000 AU distant from Sol, or about 0.8 light-years. This is still quite a distance — Voyager 1 is about 125 AU away right now — but it's far closer than Proxima Centauri's current 266,000 AU. Still, maybe the best way to engage in interstellar travel is just to wait until the time is right.

3 of 117 comments (clear)

  1. Re:That is close! by NettiWelho · · Score: 2, Informative

    If its related, then given the speed of the object we dodged a bullet in more ways than one..

    Since it was here 70 000 years ago and now is 20 light years away that means the star is traveling at 186 454 kilometers per second.

    http://en.wikipedia.org/wiki/S...

    Ordinary stars in the galaxy have velocities on the order of 100 km/s, while hypervelocity stars (especially those near the center of the galaxy, which is where most are thought to be produced), have velocities on the order of 1000 km/s.

    It is believed that about 1000 HVSs exist in our galaxy. Considering that there are around 100 billion stars in the Milky Way, this is a minuscule fraction (~0.000001%).

  2. I think you may have a math error (or I could have by MaizeMan · · Score: 4, Informative

    Here are my numbers:

    20 light years = 2* 10^14 kilometers
    70,000 years = 2.1 * 10^12 seconds

    Therefore two stars are moving apart from year other at ~100 km/second which is right in the range of what would have been expected.

  3. Re:That is close! by mcl630 · · Score: 4, Informative

    According to Wikipedia, it would take 2 million years for any comets perturbed by this encounter to get to the inner solar system.

    Scholz's Star