Three Ways to Destroy the Universe

00:06:16
https://www.youtube.com/watch?v=4_aOIA-vyBo

概要

TLDRThe video explores the eventual fate of the universe, focusing on three main scenarios: the Big Rip, Heat Death, and Big Crunch. It explains that the universe is expanding at an accelerating rate due to dark energy, leading to these potential outcomes. The Big Rip involves galaxies and atoms being torn apart as space expands faster than light. Heat Death describes a gradual decay of matter into radiation, resulting in a dark, inactive universe. The Big Crunch suggests a reversal of expansion, leading to a collapse into a supermassive black hole. The video concludes with a hopeful note about the possibility of a cyclical universe.

収穫

  • 🌌 The universe is expanding and its expansion is accelerating due to dark energy.
  • 💥 The Big Rip could tear apart galaxies, stars, and even atoms.
  • ❄️ Heat Death leads to a dark, inactive universe as matter decays into radiation.
  • 🔄 The Big Crunch suggests a reversal of expansion, collapsing into a supermassive black hole.
  • 🔄 The Big Bounce theory proposes an infinite cycle of expansion and contraction.
  • 📉 Entropy measures disorder, and the universe tends towards maximum entropy.
  • 🕳️ Hawking radiation causes black holes to evaporate over trillions of years.
  • 🔬 Quantum tunneling might allow for a spontaneous decrease in entropy.
  • 🔮 Heat Death is currently the most likely scenario for the universe's end.
  • 🌈 There is hope for a cyclical universe, starting anew after death.

タイムライン

  • 00:00:00 - 00:06:16

    The universe is expanding at an accelerating rate due to a mysterious force known as dark energy. This phenomenon challenges previous beliefs about the universe's expansion, which was thought to eventually slow down and reverse. Instead, dark energy causes the universe to expand faster and faster, leading to three potential scenarios for its ultimate fate: the Big Rip, heat death, and the Big Crunch.

マインドマップ

ビデオQ&A

  • What is dark energy?

    Dark energy is a mysterious force that causes the universe's expansion to accelerate.

  • What is the Big Rip?

    The Big Rip is a scenario where the universe expands so rapidly that galaxies, stars, and even atoms are torn apart.

  • What is Heat Death?

    Heat Death is a scenario where the universe continues to expand and matter decays into radiation, leading to a dark, inactive universe.

  • What is the Big Crunch?

    The Big Crunch is a scenario where the universe's expansion reverses, leading to a collapse into a supermassive black hole.

  • Can the universe start over after dying?

    Theoretically, a spontaneous decrease in entropy could lead to a new Big Bang after Heat Death.

  • What is entropy?

    Entropy is a measure of disorder in a system, and the universe tends towards a state of maximum entropy.

  • How does Hawking radiation affect black holes?

    Hawking radiation causes black holes to slowly evaporate over trillions of years.

  • What is quantum tunneling?

    Quantum tunneling is a phenomenon that might allow for spontaneous decreases in entropy.

  • Is the Heat Death scenario the most likely?

    Currently, Heat Death is considered the most likely outcome for the universe.

  • What is the Big Bounce theory?

    The Big Bounce theory suggests that the universe goes through infinite cycles of expansion and contraction.

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  • 00:00:01
    One day the universe will die.
  • 00:00:04
    But why? And how? And will the universe be dead forever?
  • 00:00:08
    And how do we know that?
  • 00:00:10
    First of all, the universe is expanding.
  • 00:00:13
    And not only that, the rate of its expansion is accelerating.
  • 00:00:17
    The reason: dark energy.
  • 00:00:20
    Dark energy is a strange phenomenon that scientists believe permeates the universe.
  • 00:00:25
    Until 1998 we thought that the universe must work a bit like
  • 00:00:29
    a ball that you throw into the sky.
  • 00:00:31
    The ball moves up, but at some point it has to come down again.
  • 00:00:35
    But the expansion of the universe is actually speeding up.
  • 00:00:39
    That’s like throwing a ball up and watching it fly away
  • 00:00:42
    faster and faster and faster.
  • 00:00:45
    Where is this acceleration coming from?
  • 00:00:48
    Well, we don’t know, but we call it “dark energy”.
  • 00:00:52
    Einstein thought of it first and then decided it was stupid.
  • 00:00:56
    Now, astrophysicists have decided it is plausible.
  • 00:01:00
    Trouble is, this is all very theoretical, and we don’t actually know
  • 00:01:04
    what the properties of dark energy are.
  • 00:01:07
    But there are various theories and they lead us to three scenarios
  • 00:01:10
    for the end of the universe.
  • 00:01:19
    One: the Big Rip.
  • 00:01:22
    Since its birth, the universe has been expanding.
  • 00:01:25
    For unknown reasons new spaces created everywhere equally.
  • 00:01:29
    The space between galaxies expands, so they move apart.
  • 00:01:33
    The space inside galaxies also expands, but here, gravity is strong enough
  • 00:01:38
    to keep them together.
  • 00:01:40
    In the Big Rip scenario, the expansion accelerates up to a point where
  • 00:01:44
    space expands so fast that gravity can’t compensate for this effect anymore.
  • 00:01:49
    The result is a Big Rip.
  • 00:01:51
    At first, only large structures like galaxies are torn apart,
  • 00:01:55
    since space between the single objects expands very fast.
  • 00:01:59
    Next, big bodies like black holes, stars, and planets die.
  • 00:02:03
    Their gravity isn’t strong enough to keep them together,
  • 00:02:06
    so they dissolve into their components.
  • 00:02:08
    In the end, space would expand faster than the speed of light.
  • 00:02:12
    Atoms would now be affected, and they would just disband.
  • 00:02:16
    Once space is expanding faster than light, no particle in the universe can interact
  • 00:02:21
    with any other particle anymore.
  • 00:02:23
    The universe would dissolve into countless lonely particles that won’t be able to
  • 00:02:28
    touch anything else in a strange, timeless universe.
  • 00:02:33
    Hmm, and you thought you felt lonely!
  • 00:02:37
    Two: Heat death or a Big Freeze.
  • 00:02:41
    In a nutshell, the difference between the Big Rip and heat death is that
  • 00:02:44
    in a heat death scenario matter stays intact and is converted
  • 00:02:48
    over an incredibly long but finite period of time into radiation,
  • 00:02:51
    while the universe expands forever.
  • 00:02:54
    But how does this work? Let’s talk about entropy.
  • 00:02:58
    Every system tends towards the state of highest entropy,
  • 00:03:01
    like when we have a latte macchiato.
  • 00:03:04
    Initially, it has different regions, but over time, they will
  • 00:03:07
    cool down and disintegrate, until it’s uniform.
  • 00:03:11
    And this also applies to the universe.
  • 00:03:13
    So, while the universe gets bigger and bigger,
  • 00:03:16
    matters slowly decays and spreads out.
  • 00:03:19
    At some point, after lots of generations of stars, all the gas clouds necessary
  • 00:03:25
    to form stars will be exhausted, so the universe will turn dark.
  • 00:03:30
    The remaining suns will die;
  • 00:03:32
    black holes will slowly degenerate and evaporate over trillions of years
  • 00:03:37
    due to what’s known as Hawking radiation.
  • 00:03:41
    When this process is complete, only a dilute gas of photons and light particles
  • 00:03:47
    remains, until even this decays.
  • 00:03:51
    All activity in the universe ceases at this point;
  • 00:03:54
    entropy is at its maximum and the universe is dead forever.
  • 00:04:00
    Unless… theoretically, it might be possible
  • 00:04:03
    that after an incredibly long amount of time,
  • 00:04:05
    there might be a spontaneous entropy decrease as a result of something called
  • 00:04:10
    “quantum tunneling”, leading to a new Big Bang.
  • 00:04:14
    Three: Big Crunch and Big Bounce.
  • 00:04:18
    This is the most uplifting scenario.
  • 00:04:21
    If there is less dark energy than we think or it decreases over time, gravity will be
  • 00:04:25
    the dominating force in the universe one day.
  • 00:04:28
    In a few trillion years, the rate of expansion of the universe
  • 00:04:31
    will slow down and stop.
  • 00:04:32
    After that, it reverses.
  • 00:04:35
    Galaxies will race at each other, merging as the universe becomes
  • 00:04:38
    smaller and smaller.
  • 00:04:39
    Since a smaller universe also means a hotter universe, temperatures rise
  • 00:04:43
    everywhere all at once.
  • 00:04:45
    One hundred thousand years before the Big Crunch, background radiation would be
  • 00:04:49
    hotter than the surfaces of the most stars, which means that
  • 00:04:52
    they would be cooked from the outside.
  • 00:04:54
    Minutes before the Big Crunch happens, atom cores are ripped apart,
  • 00:04:57
    before supermassive black holes devour everything.
  • 00:05:00
    Finally, all black holes would emerge into a supermassive mega-black hole
  • 00:05:05
    that contains the entire mass of the universe,
  • 00:05:07
    and in the last moment before the Big Crunch
  • 00:05:10
    it would devour the universe, including itself.
  • 00:05:14
    The Big Bounce theory states that this has happened a lot of times
  • 00:05:17
    and that the universe goes through an infinite cycle of
  • 00:05:20
    expansion and contraction.
  • 00:05:22
    Well, wouldn’t that be nice?
  • 00:05:25
    So what will actually happen to the universe in the end?
  • 00:05:28
    At the moment, heat death seems the most likely, but we at Kurzgesagt hope that
  • 00:05:33
    this “dead forever” stuff is wrong and the universe will start over and over again.
  • 00:05:39
    We don't know for sure either way, so let’s just assume
  • 00:05:42
    the most uplifting theory is true.
  • 00:05:48
    By the way, we have a Twitter account.
  • 00:06:14
    Subtitles by the Amara.org community
タグ
  • universe
  • dark energy
  • Big Rip
  • Heat Death
  • Big Crunch
  • entropy
  • Hawking radiation
  • quantum tunneling
  • Big Bounce
  • cosmology