The End of the Universe - with Geraint Lewis
The Royal Institution・2 minutes read
An astrophysics professor at the University of Sydney explains the evolution of the universe, the importance of energy, and how the universe may change over trillions of years, eventually leading to the creation of new universes with different laws of physics. Ultimately, he provides a positive outlook on the universe's future, suggesting that the cycle of universes being born from the death of previous ones could continue infinitely.
Insights
- Life on Earth is sustained by energy processes, primarily derived from the Sun, with heavy elements crucial for life created through the explosion of giant stars, highlighting the interconnectedness of cosmic events and life's existence.
- The future of the universe involves galactic collisions, star transitions, and the eventual decay of all matter due to proton disintegration, leading to the heat death state where only particles remain, but speculative physics suggests a cyclical rebirth of universes, offering hope for a continuous cosmic evolution.
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Recent questions
What is the primary energy source for life on Earth?
The Sun
How are galaxies formed according to modern astrophysics?
From big lumps
What is the significance of heavy elements released by exploding stars?
Crucial for life
What is the future of the Milky Way galaxy predicted to be?
Collision with Andromeda
How will the universe reach its end according to speculative physics?
Heat death
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Summary
00:00
"Unraveling the Universe: From Energy to Stars"
- The speaker is an astrophysics professor at the University of Sydney, specializing in cosmology.
- He aims to take the audience on a journey through time, exploring the evolution of the universe.
- Life on Earth is unique due to its evidence of life, driven by energy processes.
- Energy is crucial for all life processes, from chemical reactions to mental functions.
- The Sun is the primary energy source for life on Earth, sustaining all living organisms.
- The universe contains billions of stars and galaxies, with the Milky Way hosting around 300 billion stars.
- Observational evidence suggests life may be rare in the universe, with Earth being a special planet.
- Isaac Newton played a significant role in applying science to understand the universe, particularly through his laws of gravity.
- Modern astrophysics involves creating synthetic universes through computer simulations based on scientific laws.
- These simulations show the evolution of matter in the universe, forming structures like the cosmic web and leading to the creation of stars.
15:25
"Galaxies, Stars, and Life's Evolution"
- Galaxies are formed from big lumps, with stars evolving over time, eventually leading to giant stars running out of fuel and exploding.
- Giant stars, upon exploding, release heavy elements crucial for life, which are then spread throughout the interstellar medium for the next generation of stars.
- Elements like hydrogen and oxygen, essential for life, are formed in the hearts of stars, with gold only created when stars die under specific conditions.
- Life's existence in the early universe required the heavy elements released by exploding stars, as hydrogen and helium alone lacked the complexity necessary for life.
- The Very Large Telescope (VLT) in Chile provides a clear view of the Milky Way galaxy, where Earth orbits a typical star in a vast universe containing trillions of galaxies.
- Humans and the universe are continuously evolving, with the misconception that current states represent the pinnacle of evolution or the universe's ultimate form.
- Predicting the future of the universe faces limitations due to the inability to receive light from the future and the unresolved mathematical incompatibility between quantum mechanics and gravity.
- In the next few billion years, the Milky Way galaxy will collide with the Andromeda galaxy, leading to the formation of a new galaxy named "Milk Amida."
- The collision will result in the creation of massive stars, a glowing center around a black hole, and a brief period resembling a Christmas tree with bright blue stars filling the sky.
- Ultimately, the collision will lead to the end of the Milky Way and Andromeda galaxies, leaving behind a less structured, amorphous galaxy, with the Sun's eventual expansion leading to the Earth's destruction.
30:37
Survival in Evolving Universe: Life's Journey
- Life needs to move from star to star for survival as stars have limited lifespans.
- Technology for interstellar travel is currently lacking but may develop over billions of years.
- Traveling between galaxies might be necessary as stars within a galaxy will eventually fade.
- Dark energy dominates the universe, causing accelerated expansion and fading of distant objects.
- After a hundred billion years, distant galaxies will fade, leaving only nearby stars visible.
- Life will be isolated within galaxies, needing to adapt to survive in the evolving universe.
- In ten trillion years, galaxies will merge, creating red dwarf stars that continuously die.
- Red dwarf stars, though appearing calm, have violent solar flares that sterilize planets.
- Life may need to transition to more energy-efficient forms, possibly electronic or computational.
- Eventually, the last star in the universe will die, leaving only dead star remnants for energy.
47:00
"The Cycle of Universes: From Birth to Infinity"
- Atoms are mostly empty space, with the nucleus containing the mass of an atom, made up of protons and neutrons, held together by the strong force.
- Neutrons can decay into protons, electrons, and neutrinos due to Einstein's equation E=mc^2, while protons are expected to be stable but may decay due to an unknown force that favored matter over antimatter in the early universe.
- Protons decaying into photons and positrons over a timescale of 10^32 years will lead to the disintegration of all matter, including atoms, in the universe.
- To sustain life as protons decay, energy can be extracted from black holes, which emit Hawking radiation causing them to shrink and eventually explode, releasing all their mass.
- The universe will reach a state known as the heat death, where all usable energy for life will be depleted, leaving only electrons, positrons, and photons.
- Speculative physics suggests the universe may change its energy state, leading to a burst of expansion and the creation of new universes, potentially with different laws of physics.
- The cycle of universes being born from the death of previous ones could continue infinitely, as theorized by Douglas Adams, offering a positive outlook on the universe's future.
