What Actually Are Space And Time?

History of the Universe・2 minutes read

A great civilization awaits the end of the universe around a black hole, reflecting on the nature of time and space as the universe heads towards disorder and decay. The exploration of entropy, thermodynamics, and the integration of space and time revolutionize physics, challenging traditional views on energy conservation and the expansion of the universe.

Insights

  • Engineers of a future civilization built a new home near a black hole to extend their existence by slowing down time, allowing them to witness the far future while delaying their demise.
  • The integration of space and time into space-time by Hermann Minkowski revolutionized physics, leading to Einstein's theories of relativity that challenged Newtonian mechanics and revealed gravity as a curvature in space-time caused by mass and energy.

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Recent questions

  • What is the concept of entropy?

    Entropy dictates the universe's increase in disorder.

  • What is the Landauer limit?

    The Landauer limit defines minimum energy for erasing information.

  • What is the Laser Interferometer Gravitational Wave Observatory (LIGO)?

    LIGO detects ripples in space-time with high sensitivity.

  • What is the expanding universe theory?

    The universe expands from a single point 13.8 billion years ago.

  • What is the relationship between space-time and energy conservation?

    Space-time's expansion affects energy conservation in the universe.

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Summary

00:00

Future Civilization: Dying Universe and Relativity

  • Trillions of years in the future, a great civilization once thrived but now faces the dying universe.
  • Engineers of this civilization constructed an immense Interstellar Empire by dismantling planets and asteroids.
  • In the twilight of their time, they built a new home around a black hole to wait out eternity.
  • Time near the black hole trickled slowly, allowing them to witness the future while delaying their demise.
  • Einstein's theory of relativity revolutionized understanding of time and space over a century ago.
  • Galileo's observations on motion led to the first theory of relativity, challenging absolute rest in space.
  • Newton and Leibniz debated the nature of space, with Newton proposing absolute space and time.
  • Newton's ideas on absolute space and time prevailed for nearly two centuries until challenged by relativity.
  • Thermodynamics emerged from the Industrial Revolution, revealing the inefficiency of engines and the concept of entropy.
  • Entropy dictates the universe's inevitable increase in disorder, leading to a future of decay and disarray.

19:33

Evolution of Universe: From Disorder to Gravity

  • In 1862, Lord Kelvin proposed the idea of the universe heading towards disorder, known as heat death, due to the dissipation of mechanical energy.
  • James Clark Maxwell explored entropy and the arrow of time, using a demon in a thought experiment to separate gases based on their speeds.
  • Arguments over Maxwell's demon have persisted for over 150 years, with debates on whether the demon expends energy or uses information to sort the gas atoms.
  • The Landauer limit, proven experimentally in 2012, defines the minimum energy released from erasing a single bit of information, leading to waste heat in computer chips.
  • Thermodynamics shows that forgetting information generates waste heat, contributing to the increase in entropy in the universe.
  • Forgetting information is crucial in defining the arrow of time, suggesting that the future's existence is tied to our inability to remember.
  • The integration of space and time into space-time by Hermann Minkowski in 1908 revolutionized physics, leading to a new understanding of the universe.
  • Albert Einstein's special theory of relativity in 1905 proposed that the speed of light is constant for all observers, challenging Newtonian mechanics.
  • Einstein's general theory of relativity in 1915 revealed that gravity is not a force but a curvature in space-time caused by mass and energy.
  • Gravitational waves, predicted by Einstein, were confirmed in 1974 by Russell Hulse and Joseph Taylor through the observation of orbiting dead stars emitting energy into the universe.

38:31

"Expanding Universe Challenges Energy Conservation in Physics"

  • Taylor and Hulse received the Nobel Prize in 1993 for their Discovery related to orbital demise.
  • The Nobel Prize was later awarded for the direct detection of gravitational waves through the LIGO experiment.
  • LIGO, or Laser Interferometer Gravitational Wave Observatory, detects tiny ripples in space-time with high sensitivity.
  • LIGO's discoveries include merging black holes, neutron star collisions, and plans to hunt for the oldest gravitational waves.
  • The expansion of the universe, proven by Friedman and Hubble, involves space expanding from a single point 13.8 billion years ago.
  • Galaxies are moving away from us at an average rate of 70 kilometers per second per megaparsec.
  • The expanding universe challenges the conservation of energy due to the stretching of photons and galaxies losing speed.
  • The concept of symmetry in physics, crucial for energy conservation, is disrupted in an expanding universe.
  • Space-time's expansion affects the understanding of energy conservation and the concept of a symmetrical universe.
  • The nature of space-time, its expansion, and the concept of an expanding universe challenge traditional views on energy conservation and the physical properties of space.

57:39

Einstein's Legacy: Time Travel and Quantum Unification

  • Einstein was intrigued by the concept of a rotating universe and closed time-like curves, leading to the possibility of time travel.
  • Google's wife knitted Einstein a sweater, but it was not part of the final gift he received.
  • Einstein passed away in 1955, followed by Google in 1978, with Google questioning astronomers about the universe's rotation.
  • Physicists explored mathematical shortcuts through space and time, finding solutions where space and time are extremely warped.
  • Time travel remains a theoretical possibility in Einstein's relativity, with the addition of spin to a black hole causing space and time to twirl.
  • The Dirac equation unified Einstein's relativity and quantum mechanics, predicting the existence of the anti-electron.
  • Quantum field theory, based on the Dirac equation, describes fundamental particles and forces, including anti-particles.
  • The search for a Theory of Everything to merge quantum mechanics and general relativity has led to theories like string or M Theory and loop quantum gravity.
  • Speculation arises about the non-existence of space and time, suggesting they are emergent phenomena experienced by macroscopic beings.
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