Prof. Heidi Newberg
Rensselaer Polytechnic Institute
This is the story of the Universe. The details may not all be true, but it's what we tell our students.
Universe began as an infinitely dense point in space. The particles and the physics are exotic.
At 10-30 s, the Universe expands by a factor of 1026, in a process we call Inflation.
10-14 s later, baryons and antibaryons annihilate and we are left with a quark-gluon plasma, in which quarks can exist by themselves, outside of a hadron.
Where have all the free quarks gone?
Long time passing.
Where have all the free quarks gone?
Long time ago.
Where have all the free quarks gone?
Gone to protons every one.
When will it ever end?
When will it ever end?
Well, some are in neutrons too, but not all the flowers were picked by young girls, either.
The protons and neutrons bind together into nuclei of light elements, mostly hydrogen.
Where have all the protons gone?
Long time passing.
Where have all the protons gone?
Long time ago.
Where have all the protons gone?
Hydrogen atoms — 75% of them —
When will it ever end?
When will it ever end?
300,000 years after the Big Bang, hydrogen atoms form, the CMBR is released, the dark ages begin, and last until quasars and the first stars light up the Universe.
Where have hydrogen atoms gone?
Long time passing.
Where have hydrogen atoms gone?
Long time ago.
Where have hydrogen atoms gone?
Made the first stars every one.
When will it ever end?
When will it ever end?
Matter falls into black holes that will eventually be the nuclei of galaxies, emitting light as quasars. Also, a generation of very massive and short lived stars (Population III) is created. These energetic events reionize the gas. Stars are numbered in order of their discovery, which is the opposite of the order they appeared. The Sun is Population I, older stars are Population II, and the first stars, which have never been directly observed, are Population III.
Where have all the first stars gone?
Long time passing.
Where have all the first stars gone?
Long time ago.
Where have all the first stars gone?
Supernovae every one.
When will it ever end?
When will it ever end?
The heavier elements of the periodic table are created by fusion in the centers of massive stars, and then released into the interstellar medium in supernova explosions, that end these stars' lives.
Where have supernovae gone?
Long time passing.
Where have supernovae gone?
Long time ago.
Where have supernovae gone?
Enriched the gas to make Pop II.
When will it ever end?
When will it ever end?
The enriched gas is made into Pop II stars in small clusters.
Where have all Pop II stars gone?
Long time passing.
Where have all Pop II stars gone?
Long time ago.
Where have all Pop II stars gone?
Formed dwarf galaxies every one.
When will it ever end?
When will it ever end?
These clusters hierarchically merge to make ever larger galaxies.
Where have the dwarf galaxies gone?
Long time passing.
Where have the dwarf galaxies gone?
Long time ago.
Where have the dwarf galaxies gone?
Merged to make the Milky Way.
And they are merging still.
And they are merging still.