ASTR 1040 Accel Astro: Stars

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ASTR 1040 Accel Astro Stars Galaxies
Structure formation model

• Prof. Juri Toomre TAs Ben Brown, Adam Jensen
• Lecture 30 Thur 4 May 06
• zeus.colorado.edu/astr1040-toomre

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Ultimate Joys of Cosmology

• Look at early eras involved with the big-bang
  beginning
• Discuss development of large-scale structure in
  the universe
• Final Exam Review tonight Thur 4 May by Ben
  Brown, 7-9pm Review Set 4 still available
• Final Exam (comprehensive) here, Mon 8 May
  130-400 pm

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Evolution of Universe
1 billion years
380,000 years
3 minutes
4
Models of universe and its fates
SIZE
OPEN
CRITICAL (FLAT)
CLOSED
NOW
TIME
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How can universe be accelerating??

• Conjecture An unknown force at large scales
  begins to counteract pull of gravity
• Dark energy outweighs every other form of
  mass/energy
• 73

Baryons 4.4 Cold Dark Matter 23 , with a
FLAT universe and early inflation
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• With alarming new ideas like inflation and dark
  energy .
• No doubt Einstein would have been concerned
  maybe even troubled!

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Grand unified theories of physics predict that
the very early universe (10-32 seconds after the
start) may have had a phase transition, releasing
energy and causing
D.

• A. The universe to vastly expand (inflation)
• B. Tiny fluctuations predicted by quantum
  mechanics to expand large enough to contribute to
  the fluctuations we see in the cosmic background
  radiation now
• C. Any curvature of space to be reduced
• D. All of the above

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• Some say the world will end in fire
• Some say with ice
• From what Ive tasted of desire
• I hold with those who favor fire
• But if I had to perish twice
• I think I know enough of hate
• To say that for destruction ice
• Is also great
• And would suffice
• -- Robert Frost

National Poet Laureat
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Now turn to the VERY Beginning
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Big bang idea COSMIC FIREBALL George GAMOW (1948
)
Oops ! Pure HELIUM
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Making helium in first 3 minutes
JUST DO NOT MAKE EVERYTHING INTO HELIUM !
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HOT Big Bang did the trick!
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Matter and Anti-matter

• Protons slightly outnumber anti-protons
• At end of particle era, universe contains some
  matter!
• Universe ratio today
• 1 billion photons (light)
• 1 leftover proton
• (matter)

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H and He ratio after 3 minutes
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During first 3 minutes Making the elements
How much DEUTERIUM made depends on density
of ordinary matter (baryons)
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Sensitivity in making the light elements
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After first 3 minutes
RADIATION ERA --gt 380,000 yr
MATTER ERA
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Era of Atoms
After recombination

• Finally cool enough for electrons to combine with
  nuclei to form atoms (380,000 yrs)
• Photons now decoupled free to become CMB of
  future
• Universe becomes transparent to light

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What is Olbers paradox?
D.

• A. If the universe was infinite, any direction
  you looked you would eventually see a star
• B. If the universe was infinitely old, the
  starlight would have time to get here
• C. The sky should look bright at nightbecause
  all directions would have starlight
• D. All of the above

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Era of Atoms and Galaxies

• About 1 billion years after Big Bang, first stars
  and galaxies start to form ( Z 10 ?)

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Forming first stars and galaxies
SIMULATIONS
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Simulating large-scale structure
COLD DARK MATTER
GALAXY CLUSTERING
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Forming filaments in cosmic fabric Kravtsov
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Evolve and rotate viewing
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Co-moving frame in overview
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Simulation Dark matter structure now
140 M ly across
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Dark matter cosmic web
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Forming galaxy clusters
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Web of 3 million real galaxies in sky
30 degress across
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Galaxy clustering in ever deeper surveys
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Galaxies are always movingHubble flow
respond to local clustering
Milky Way at center is moving toward Virgo
cluster, then Coma supercluster
600 M ly across
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The Big Mysteries

• What will be the fate of the universe ?
• What is the universe made of ?
• What is the dark matter ?
• Is the theory of inflation correct ?
• What is the dark energy ?
• Which of this, if any, should we believe?

Science is not about belief, its about
exploration