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  • What would happen to you if a black hole the size of a coin

  • suddenly appeared near you?

  • Short answer: you’d die.

  • Long answer: it depends.

  • Is it a black hole with the mass of a coin,

  • or is it as wide as a coin?

  • Suppose a US nickel with the mass of about 5 grams

  • magically collapsed into a black hole.

  • This black hole would have a radius of about 10 to the power of −30 meters.

  • By comparison, a hydrogen atom is about 10 to the power of −11 meters.

  • So the black hole compared to an atom is as small as

  • an atom compared to the Sun.

  • Unimaginably small!

  • And a small black hole would also have an unimaginably short lifetime

  • to decay by Hawking radiation.

  • It would radiate away what little mass it has in 10 to the power of −23 seconds.

  • Its 5 grams of mass will be converted to 450 terajoules of energy,

  • which will lead to an explosion roughly 3 times bigger than

  • the atomic bombs dropped on Hiroshima and Nagasaki combined.

  • In this case, you die.

  • You also lose the coin.

  • If the black hole had the diameter of a common coin,

  • then it would be considerably more massive.

  • In fact, a black hole with the diameter of a nickel

  • would be slightly more massive than the Earth.

  • It would have a surface gravity a billion billion times greater

  • than our planet currently does.

  • Its tidal forces on you would be so strong

  • that they’d rip your individual cells apart.

  • The black hole would consume you before you even realized what’s happening.

  • Although the laws of gravity are still the same,

  • the phenomenon of gravity that you’d experience would be very different

  • around such dense objects.

  • The range of the gravitational attraction

  • extends over the entire observable universe,

  • with gravity getting weaker the farther away you are from something.

  • On Earth right now, your head and your toes are approximately the same distance

  • from the center of our planet.

  • But if you stood on a nickel-sized black hole,

  • your feet would be hundreds of times closer to the center,

  • and the gravitational force would be tens of thousands of times as large

  • as the force on your head and rip you into a billion pieces.

  • But the black hole wouldn’t stop with just you.

  • The black hole is now a dominant gravitational piece

  • of the EarthMoonBlack-Hole-of-Death system.

  • You might think that the black hole would sink towards the center of the planet

  • and consume it from the inside out.

  • In fact, the Earth also moves up onto the black hole and begins to bob around,

  • as if it were orbiting the black hole,

  • all while having swathes of mass eaten with each pass,

  • which is much more creepy.

  • As the Earth is eaten up from the inside,

  • it collapses into a scattered disk of hot rock,

  • surrounding the black hole in a tight orbit.

  • The black hole slowly doubles its mass by the time it’s done feeding.

  • The Moon’s orbit is now highly elliptical.

  • The effects on the Solar system are awesome

  • in the Biblical sense of awesome, which means terrifying.

  • Tidal forces from the black hole would probably disrupt the near-Earth asteroids,

  • maybe even parts of the asteroid belt,

  • sending rocks careening through the Solar system.

  • Bombardment and impacts may become commonplace

  • for the next few million years.

  • The planets are slightly perturbed, but stay approximately in the same orbit.

  • The black hole we used to call Earth will now

  • continue on orbiting the Sun in the Earth’s place.

  • In this case, you also die.

  • This bonus video was made possible by your contributions on Patreon.

  • Thank you so much for your support!

  • The topic is based on a question on the AskScience subreddit

  • and the glorious answer by Matt [Caplin?], who also worked with us on this video.

  • Check out his blog, Quarks and Coffee, for more awesome stuff like this!

  • If you want to discuss the video, we have our own subreddit now.

  • To learn more about black holes or equally interesting neutron stars, click here.

  • Subtitles by the Amara.org community

What would happen to you if a black hole the size of a coin

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B1 UK black hole hole black coin earth nickel

What if there was a black hole in your pocket?

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    mommy posted on 2015/08/23
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