What if there was a black hole in your pocket?
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What if there was a black hole in your pocket?

November 19, 2019

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
Earth–Moon–Black-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

Only registered users can comment.


  2. So… i am not an.. English native, i am actually Brazilian (Portuguese language) and i have no idea how to pronounce "kurz..ge..gagsta?" Can you help me?

  3. One day I dropped my purple comb brush behind my bed, And I’m not even kidding it disappeared, I search EVERYWHERE and I still didn’t find it, I think a wormhole sucked it in!! When I grow up I’ll be study astrology and I WILL find out what happened to me purple comb brush!

  4. Would light be able to bounce off such a small gravity black hole? I mean the wide one but now I think the other black hole too but it's way too small

  5. The black hole would orbiting the sun? Meaning,it would be more massive than Earth,but not more massive of the Sun,right?

  6. Me: Okay Maxy here is your new home!
    Maxy: Eats it
    Me: Ma-
    Maxy: Eats the entire universe
    Me: Maxy! How many times do I have to tell you to stop eating everything?

  7. There is no such thing as "Hawking Radiation" – it's the 20th/21st century equivalent of Orgone. It has always been a load of bollocks concocted by a man who confused virtual particles for real ones, conflated negative charge for negative mass, and didn't seem to understand the difference between an electron and photon.

    I wonder how many years it will take before someone with appropriate authority has the balls to say "Hawking was full of s***" and have everyone breathe a sigh of relief?

  8. me:what happens when……
    kurzgesagt : you die
    me: let me finis….
    kurzgesast : you die
    me: (annoyed)… for god's sake… plz listen…
    kurzgesagt :…….
    me: so, what happens when you step on…..
    kurzgesagt :you die!
    me: 😑😑😑😑😑

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