What is the Ultimate Fate of the Universe
- Slides: 16
What is the Ultimate Fate of the Universe? Nick Kaiser
The Universe is full of galaxies
The Universe is Expanding! Expansion discovered in the ‘ 30 s Extrapolating back, the “Big Bang” occurred about 13 billion years ago
Big-bang cosmology • Future evolution depends on: – How fast is the expansion? – How much stuff is there to pull it back? • The key question: Does the universe have “escape velocity”? • Or: Does the density of stuff exceed the “critical value”?
How much matter is there…. • Ordinary matter (atoms, ions, electrons) – Galaxies (1% of critical density)
The Coma cluster Optical image X-ray image Roughly 4 times as much mass in hot gas as in all the galaxies
How much matter is there…. • Ordinary matter (atoms, ions, electrons) – Galaxies (approx 1% of critical density) – Hot gas (approx 3%) • Much too small to make the universe recollapse • 4% total value also confirmed independently from physics of the first 3 minutes
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How much matter is there…. • Ordinary matter (atoms, ions, electrons) – Galaxies (1% of critical density) – Hot gas (approx 3%) • Dark Matter – Approx 23% of critical density – Still too little to halt the expansion • Is that all?
Accelerating expansion • Observers were using supernovae to measure the expansion history • They expected to see the expansion slowing down because of gravity • They found the opposite - the expansion is speeding up! • The future expansion will be dominated by “Dark Energy”
“Concordance” cosmology
How will the Universe end? • Currently favored model says the universe will expand forever – Most of all the galaxies we see will disappear – The future is cold, dark and rather lonely • However – Observations are difficult and uncertain – The theory is incomplete – So expect future surprises
Dark Energy • The new ingredient – Rebirth of an old idea • Invoked by Einstein as the “cosmological constant” – His self-confessed “biggest blunder” • And by Fred Hoyle in the “steady state cosmology” – Gained credibility in the ‘ 80 s when applied to the early universe in the “inflationary theory” • Solved many problems – Similar to a magnetic field • Allows creation of matter from nothing • Causes a repulsive gravitational field • Leads to accelerating expansion – Now seen in the recent expansion history
- The ultimate fate of the universe
- Which animal hides during the battle of cowshed?
- What means obvious fate
- Fate map of frog blastula
- Fate slew him but he did not drop
- Fate map of human embryo
- William wallace fate
- Fate of pyruvate
- Obvious fate
- Fate of thrombus slideshare
- Example of character vs character conflict
- Macbeths quotes
- What fate does antigone compare to her own
- Fate of germ layers
- Fellowships of fate
- Fate exam
- King acrisius fate