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

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 1:30-4:00 pm

Evolution of Universe 1 billion years 380,000 years 3 minutes

Models of universe – and its fates SIZE OPEN CRITICAL (FLAT) CLOSED NOW TIME

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

With alarming new ideas like inflation and dark energy …. No doubt Einstein would have been concerned – maybe even troubled!

D. A. The universe to vastly expand (‘inflation”) 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

Some say the world will end in fire Some say with ice From what I’ve 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

Now turn to the VERY Beginning

Big bang idea COSMIC FIREBALL George GAMOW (1948) Oops ! Pure HELIUM

Making helium in first 3 minutes JUST DO NOT MAKE EVERYTHING INTO HELIUM !

HOT Big Bang did the trick!

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)

H and He ratio after 3 minutes

During first 3 minutes Making the elements How much DEUTERIUM made depends on density of ordinary matter (baryons)

Sensitivity in making the light elements

After first 3 minutes RADIATION ERA --> 380,000 yr MATTER ERA

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

What is Olber’s paradox? 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 night–because all directions would have starlight D. All of the above

Era of Atoms and Galaxies About 1 billion years after Big Bang, first stars and galaxies start to form ( Z = 10 ?)

Forming first stars and galaxies SIMULATIONS

Simulating large-scale structure COLD DARK MATTER GALAXY CLUSTERING

Forming filaments in cosmic fabric Kravtsov

Evolve and rotate viewing

Co-moving frame in overview

Simulation: Dark matter structure now 140 M ly across

Dark matter cosmic web

Forming galaxy clusters

Web of 3 million real galaxies in sky ~ 30 degress across

Galaxy clustering in ever deeper surveys

Galaxies are always moving: “Hubble flow” + respond to local clustering Milky Way at center is moving toward Virgo cluster, then Coma supercluster 600 M ly across

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, it’s about exploration…