How Big Is The Universe?
Cool Worlds・18 minutes read
Heinrich Olbers questioned the universe's size in 1823, a paradox resolved by Edwin Hubble in the 20th century with the discovery of an expanding universe and galaxies beyond the Milky Way. Modern astronomy debates the universe's scale, with theories including a flat, finite universe with potential torus or Klein bottle shapes, impacting concepts of space travel and existential reflections.
Insights
- Edwin Hubble's discovery of an expanding universe in the 20th century resolved Olbers' paradox by confirming galaxies beyond the Milky Way, like Andromeda, millions of light years away.
- Modern astronomy, grappling with the size of the universe, explores the curvature of space, hinting at a potentially finite yet vast cosmos that may wrap around itself, challenging traditional notions of space and identity.
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Recent questions
What is Olbers' paradox?
Olbers' paradox questions the size of the universe.
Who confirmed galaxies beyond the Milky Way?
Edwin Hubble confirmed galaxies like Andromeda.
What is the curvature of the universe?
The universe's curvature is found to be flat.
How was the 2-torus shape created?
The 2-torus shape was created by isometric embedding.
What are the implications of a 3-torus universe?
A 3-torus universe has implications for space travel.
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Summary
00:00
Universe's Size: Infinite or Finite?
- In 1823, Heinrich Olbers observed a dark night sky, leading to Olbers' paradox questioning the size of the universe.
- Edwin Hubble's discovery of an expanding universe in the 20th century resolved Olbers' paradox.
- Modern astronomy continues to ponder the size of the universe, whether it is finite or infinite.
- Astronomical demotions in history include Copernicus and Kepler challenging the geocentric view, and Bessel measuring distances to stars.
- Edwin Hubble confirmed the existence of galaxies beyond the Milky Way, like Andromeda, millions of light years away.
- Modern telescopes have captured images of the most distant galaxy, GN-z11, 32 billion light years away.
- The visible universe is smaller than the observable universe due to the ionized plasma era, with the latter extending 45 billion light years.
- The curvature of the universe, determined by the Omega_k parameter, is found to be flat to within 0.19%.
- Flatness does not necessarily imply infinite space, as a flat universe can still be finite, like a 2-cylinder model.
- The cosmological principle suggests that the universe may wrap around itself, potentially affecting its size estimation.
19:20
"Exploring 3D Torus Embeddings and Universe"
- A 2-torus is formed by connecting two ends of a cylinder, requiring material stretching to create a donut-shaped torus.
- John Nash demonstrated the isometric embedding of a 2-torus into three dimensions by adding tiny corrugations during the procedure.
- A French team used supercomputers in 2012 to calculate the 3D shape of the embedded 2-torus, adhering to Pac-Man style rules.
- Joel, known as the 3D Printing Nerd, successfully created a 3D print of the embedded 2-torus, surpassing the challenges faced by New York printing agencies.
- The universe could be represented by a 3-torus or other manifolds, including the non-orientable Klein bottle, with implications for space travel.
- The concept of an infinite universe poses challenges to physicists, probability theory, and the cosmological principle, leading to existential reflections on identity and impact.
