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Exactly how terrified should I be at this news? Really super terrified, right?

• worldsayshi 4y ago
  Not terrified at all. I see no reason to be.
  • cuoco 4y ago
    Unless it starts moving closer...
    • zeusk 4y ago
      With it being 1560 light years away, we'll (parent, you, me etc) be long gone before it's a concern for Earth.
    • worldsayshi 4y ago
      It's like worrying about a blind grizzly bear in a zoo on the other side of the planet moving closer to you.
• simfoo 4y ago
  The closest one has 10 solar masses. Gravitationally there is zero difference between a black hole and a regular star except that the black hole has a way smaller radius. So for us it doesn't matter _at all_.
  • chongli 4y ago
    Yes. If the Sun somehow instantly collapsed into a 1 solar mass black hole, it would have no effect on Earth's orbit. The Schwarzschild radius of a 1 solar mass black hole is a bit under 3km, so the event horizon would be 3km in radius. For comparison, the Sun's current equatorial radius is about 696,000km. To fall into the former Sun black hole would be much more difficult than falling into the Sun as it is now. You'd pretty much have to make a deliberate effort to "land" on the event horizon.
• executesorder66 4y ago
  If you should be terrified, you'd see it show up everywhere. At least as much news coverage as COVID got. If something happened that was likely to end the whole world, and it was detectable by many people, then you wouldn't only hear about it on one random internet forum. This is pure clickbait.
  • sebzim4500 4y ago
    How is it clickbait? The headline is not in any way misleading.
    • executesorder66 4y ago
      The HN title has been changed.
• eurekin 4y ago
  Well, if it had choosen our planet as a direct destination for (providing it has means to travel at light speed) collision, we'd only have 1560 years to escape. There are a couple of comically improbable conditions that would happen only in fantasy to start threating us
  • proto-n 4y ago
    On the other hand, if it had chosen our planet as its destination 1559 years ago, then we would have no way of being aware of this fact until next year
    • codethief 4y ago
      But then we wouldn't be seeing it at a distance of 1560 ly right now.
      • CaptainNegative 4y ago
        In principle it could be approaching us at near the speed of light (for example, if it was hit by something big going near the speed of light from the other direction a few days after the presently observed light was emitted) and we would never know it until it's just about too late. The same, of course, could be said for any other celestial body, currently observed or otherwise.
        • codethief 4y ago
          > a few days after the presently observed light was emitted) and we would never know it until it's just about too late. Right, good point! I shouldn't have skipped my morning coffee. > if it was hit by something big For the record, I assume you mean not a literal "hit" but some sort of binary interaction with another very massive object that ends up transferring (a lot of) momentum to the black hole.
        • AnimalMuppet 4y ago
          It's 10 solar masses. If it were hit by something big (100 solar masses, say) traveling at 0.9 c, then the result would be headed our way at a bit less than 0.9 c. At 1560 light years away, that would take 1733 years, so it wouldn't get here for another 173 years. But why bother with this black hole? If you want to go that route, why not just imagine that there could be a 100-solar-mass something headed directly at us at 0.9 c, and it will show up tomorrow?
• komali2 4y ago
  I recently read "A Brief History of Black Holes" by Dr. Becky Smethurst and I recommend it if you're interested in these things. She wrote that the math indicates you have no reason to fear a black hole consuming you, or this solar system. Black holes are just massive objects, no different from any other "massive object" in the universe. It's pretty easy / common for stuff to orbit massive objects, rather than fall into them. Furthermore I vaguely remember her mentioning another force involved with pushing things away from black holes, such that physicists of today aren't able to reach consensus on the idea that maybe one day all mass in the universe will be in one black hole or another, it seems there's other forces involved that may prevent that from happening (though there are hypothesis around that time is a cycle of all things falling into a universal singularity which then explodes into a big bag and the cycle continues). In short though, no, you shouldn't be terrified. There has been an ongoing theory for a while that there's a micro black hole somewhere near pluto causing our predictions for its orbit to be just ever so slightly off. https://www.newscientist.com/article/mg24933280-100-is-there-an-ancient-black-hole-at-the-edge-of-the-solar-system/ https://www.newscientist.com/article/mg24933280-100-is-there... If it's there, it's been there basically forever, and its event horizon, if it's a micro black hole, is hilariously small. https://www.goodreads.com/en/book/show/61324554 https://www.goodreads.com/en/book/show/61324554 Also as others have said, if it's coming directly for earth, it would take at least 1500 years to get here, which is plenty of time for humans to do something about it. Almost certainly you'll already be dead anyway.
  • Koshkin 4y ago
    Well, merely disturbing the Earth’s orbit would be deadly enough.
• isaacg 4y ago
  Your reaction should be "astronomy fun fact, that will have no direct effects on anyone's life." This black hole is so dim and distant that it required a super powerful telescope to even notice it exists. It will have no effect on life on earth, except by adding to scientific understanding of the cosmos. Moreover, black holes aren't death machines or anything. This black hole puts out much less light and energy than an equivalent-mass star. It's quite safe.
  • delta_p_delta_x 4y ago
    A lot of people seem to have the impression that black holes are like vacuum cleaners, sucking up anything that comes near. If the Sun were replaced with a black hole of equal mass, apart from the heat and light going out, we wouldn't notice anything. All the planets would still orbit more-or-less the same.
    • deleted 4y ago
      [deleted]
    • klyrs 4y ago
      The scary thing would be a rogue, massive black hole hurtling through our solar system at a fraction of c. Such an event could destabilize orbits enough to make the remaining time on Earth quite terrifying. But, good news: if such an event should ever occur, we would be utterly powerless to change a damned thing, so we can rest easy knowing that panic is a waste of energy better spent on hedonistic pursuit.
  • billpg 4y ago
    Sorry. I can't hear you over all the panic screaming.
  • Idiot_in_Vain 4y ago
    >> It's quite safe. Famous last words...
• deleted 4y ago
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