The other end of a black hole โ€“ with James Beacham

The Royal Institution
16 Jun 202257:37
EducationalLearning
32 Likes 10 Comments

TLDRThis talk explores black holes - cosmic phenomena still full of mystery that both terrify and intrigue. It examines what black holes are, how they warp spacetime, the similarities between black holes and the expansion of the universe itself, whether our universe exists inside a black hole, and more. The speaker also discusses attempts to create small black holes in particle colliders to better understand gravity and quantum mechanics, and imagines a future where humans can travel to and explore black holes firsthand. Ultimately, black holes represent profound truths about the limitations of knowledge and provide opportunities to reconstruct a broken society.

Takeaways
  • ๐Ÿ˜ฒ Black holes warp and bend the fabric of space itself due to the presence of matter and energy density.
  • ๐Ÿ˜ฎโ€๐Ÿ’จ If a black hole is large enough, you could survive inside the event horizon.
  • ๐Ÿ‘ฉโ€๐Ÿ”ฌ Our observable universe could exist inside a giant black hole with similar interior mathematical properties.
  • ๐Ÿ”ญ Black holes separate the physical world into two unreachable regions and act as barriers to knowledge.
  • โš›๏ธ Understanding black holes could unlock mysteries about the relationship between gravity and quantum mechanics.
  • ๐Ÿ”ฌ The Large Hadron Collider won't create dangerous black holes due to the extreme weakness of gravity at that scale.
  • ๐Ÿš€ Building a particle collider around the moon could be possible with future technology to further study quantum gravity.
  • ๐Ÿ˜  Societal black holes like climate change and inequality seem impossible but are human-made and can be unmade.
  • ๐Ÿ‘ถ๐Ÿป Primordial black holes the size of apples could be sprinkled across our universe from the first moments after the Big Bang.
  • ๐Ÿ˜Š Studying black holes pushes the boundaries of knowledge and reminds us space exploration belongs to all humanity.
Q & A
  • What is the main reason black holes fascinate physicists?

    -Black holes fascinate physicists because they could help answer one of the biggest open questions in physics - how gravity and quantum mechanics relate to each other.

  • Why can't we currently test the hypothesis that our universe exists inside a black hole?

    -We can't currently test this hypothesis because: 1) Going into a black hole is a one-way trip, so we could never report back findings. 2) There are no experiments that distinguish this from other hypotheses. 3) We don't know how to meaningfully contact another universe.

  • How are black holes and the expansion of the universe connected?

    -As the universe expands, space itself stretches - like dots on an inflating balloon moving away from each other. Black holes involve space bending and flowing inwards instead of outwards.

  • Could the Large Hadron Collider create dangerous black holes?

    -No, the Large Hadron Collider collisions involve the strong nuclear force, which is vastly more powerful than gravity at that scale. So there is no danger of creating stable, growing black holes.

  • What happens when you cross the event horizon of a supermassive black hole?

    -Crossing the event horizon of a sufficiently large black hole, you wouldn't initially notice anything different. But it would be a one-way trip, and over time you would be stretched and pulled apart by tremendous gravitational forces.

  • How are primordial black holes formed?

    -Primordial black holes could have formed from density fluctuations in the early universe, within the first second after the Big Bang. They would then exist across space from that time.

  • Could we ever directly observe what occurs inside black holes?

    -We may never directly observe the interior of black holes. Our best chance would come from creating tiny, quantum black holes in a particle collider and detecting their decays.

  • What is the relationship between black holes and wormholes?

    -Some solutions to the equations of general relativity show that the interior of black holes could contain passages called wormholes, possibly even connecting to other universes, but this remains hypothetical.

  • Why does the concept of the Planck scale matter for understanding black holes?

    -The Planck scale is the level at which gravity is theoretically equal in strength to other fundamental forces. Studying microscopic black holes could let us probe quantum gravity at these extreme energies.

  • How are black holes analogous to societal problems?

    -Like black holes forming from gradual changes over time, societal problems can emerge imperceptibly until it seems too late for gradual reform. But just as the only way out of a black hole is through its center, we must go through the depths of systemic issues to address them.

Outlines
00:00
๐Ÿ˜ฒ Introduction to physics of black holes

The opening paragraph introduces the concept of black holes, describing them as twisted vortices so dense they puncture spacetime. It foreshadows an upcoming journey the listener will take 500 years in the future to explore a black hole up close.

05:00
๐Ÿ˜ฎโ€๐Ÿ’จ Everyone experiences gravity the same way

This paragraph highlights our common experience with gravity across differences like gender, skin color, and posture. It emphasizes that gravity is a profound insight requiring a complete change in our understanding of reality.

10:01
๐Ÿคฏ Einstein showed space itself warps and flows

Einstein's theory of general relativity explained gravity as space and time warping due to the presence of matter and energy density. This radically changed perspectives on reality. The extent of warped space is illustrated by how fast objects must travel to escape the gravity of the sun, neutron stars, and black holes.

15:02
๐ŸŒ€ Black holes trap even light beyond their event horizon

Black holes have an event horizon beyond which space flows inward faster than light, trapping everything inside. Not even light can escape a black hole once past this point of no return. Fish in swirling water is used as an analogy.

20:03
๐Ÿ•ณ Mathemetically, exterior and interior spacetimes of black holes resemble each other

The paragraph examines mathematical similarities between the exterior and interior perspectives of black holes. In both cases there is an elusive boundary horizon that information cannot cross, making direct exploration of black holes impossible.

25:04
๐Ÿค” Are we inside a giant black hole ourselves?

Calculation showing the entire observable universe could fit inside a black hole raises the mind-bending question of whether we already live inside a giant black hole. While mathematically possible, evidence to test this hypothesis remains scarce.

30:07
๐Ÿšซ No way to contact or gather evidence from another universe

Even if black holes connected to other universes, we currently lack coherent concepts or experiments to contact or gather evidence from them. Our experimental devices and concepts assume the constants of our universe hold true universally.

35:07
๐Ÿ˜ฑ Colliding protons at CERN won't make tiny black holes

Calculations show the Large Hadron Collider does not produce enough gravitational force between protons to make black holes. However, theoretical mini black holes that quickly evaporate could provide clues to unify gravity and quantum mechanics.

40:09
๐ŸŒ™ Building a particle collider around the moon might reach high enough energies

As an experimentalist seeking evidence, the author loves fantastical hypotheses about black holes birthing universes but needs ways to test them. Colliding particles at high enough energies could produce quantum gravity effects. A collider encircling the moon could reach these energies.

45:10
๐Ÿ˜” No escaping societal black holes like climate change

Similar to how event horizons trap all within black holes, society's slow descent into climate crisis is a societal black hole requiring radical new thinking. As social constructs rather than laws of nature, the systemic inequities driving societal black holes can and must be dismantled.

50:12
๐ŸŒŽ Space exploration for all humanity, not profit

A hypothetical moon collider would be for pure curiosity to benefit humanity, unlike present trends of space exploitation for wealth and profit fueling climate crisis on Earth. We must reorient systems enabling extreme inequality so society stops repeating mistakes.

Mindmap
Keywords
๐Ÿ’กblack hole
A black hole is an extremely dense region in space with very strong gravity where even light cannot escape. Black holes are a major theme in the video, which discusses what they are, how they form, whether our universe exists inside a black hole, and the possibility of creating small black holes in particle colliders to understand quantum gravity.
๐Ÿ’กevent horizon
The boundary around a black hole beyond which nothing can escape, not even light. Crossing the event horizon is a point of no return. The video explores the experience of crossing an event horizon and how it would cutoff communication with the outside world.
๐Ÿ’กgravity
The force of attraction between objects with mass. Understanding gravity and reconciling it with quantum mechanics is a main focus and mystery explored in the video. Gravity is what causes black holes.
๐Ÿ’กspacetime
The fabric of space and time that can bend, warp and flow, especially near objects with mass. According to Einstein's theory of relativity, gravity is the result of warped spacetime.
๐Ÿ’กcosmology
The study of the origin and structure of the universe. Cosmology plays a role in the video when considering whether our universe exists inside a black hole and in discussing the Big Bang.
๐Ÿ’กquantum mechanics
The physics of subatomic particles. A major unsolved mystery is how to reconcile quantum mechanics with gravity into a complete theory of quantum gravity, which may require rethinking space itself.
๐Ÿ’กparticle collider
A machine that accelerates particles close to the speed of light and collides them to study fundamental physics. The video discusses whether small black holes could be created in particle colliders like the Large Hadron Collider.
๐Ÿ’กprimordial black hole
Hypothetical tiny black holes, like the apple-sized one discussed in the video, that may have formed right after the Big Bang. Their existence is speculative but would have implications for cosmology and quantum gravity.
๐Ÿ’กPlanck scale
An extremely small distance and high energy scale at which quantum effects of gravity are believed to dominate. Building bigger and bigger particle colliders to reach higher energies gets us closer to understanding physics at the Planck scale.
๐Ÿ’กanthropic principle
The philosophical consideration that certain physical constants in our universe seem finely tuned to allow for conscious observers like humans to exist and contemplate them. This perspective plays into the video's narrative device of imagining the viewer travelling to a black hole in some far future time.
Highlights

Einstein completely changed our understanding of gravity and the nature of space itself

Black holes separate the physical world into two regions with an event horizon that can never be reached

The math of a black hole's interior is almost identical to its exterior, suggesting we may live inside one

Our universe could have been born from a black hole in another universe

Black holes are cosmic eyes staring back at us and the emptiest things we've ever seen

We can't currently test if we live inside a black hole, but we should never underestimate humanity's ability to test impossible ideas

Understanding how black holes form could allow us to design experiments to study them indirectly

There's no showstoppers to building a particle collider around the moon's circumference

Our societal black hole is an opportunity to construct a better world by radically rethinking our structures

The moon belongs to everyone, and space exploration should be centered around humanity's curiosity, not profit

The structures leading to societal black holes are human-made, so they can be human-unmade

We need the courage to unmake the systems causing wealth inequality, climate change, and more

It's up to us to fix inequities so future generations can explore the cosmos

Black holes exemplify the limitations of knowledge - we can never know what lies beyond their event horizon

Black holes are profound cosmic objects that push our understanding of reality's very fabric

Transcripts
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