Cosmic Order and Disorder

Dr. Green

Symmetries

At the Beginning of the Universe Currently

Conservation laws At the End of the Universe

Symmetries at the Beginning of the Universe

The universe began in thermal and chemical equilibrium.

The universe had more symmetry (homogeneity) at its beginning

Our universe is thought to have begun as an infinitesimally small, infinitely hot, infinitely dense, something.

Gravitational Singularity

all physical laws are indistinguishable from one another,

space and time are merged indistinguishably and cease to have any independent meaning.

finite matter is actually squished into infinite density

matter is forcibly compressed to a point (a space-like singularity)

Something from Nothing?

"that moment [of the Big Bang] there was nothing; during and after that moment there was something."

"Prior to the singularity, nothing existed, not space, time, matter, or energy - nothing."

Before the Big Bang

There was a contracting universe with similar space-time geometry to our expanding universe. The universe collapsed and then “bounced” as the Big Bang.

As gravitational forces pulled this previous universe inward, it reached a point at which the quantum properties of space-time cause gravity to become repulsive, rather than attractive.

Symmetries at the End of the Universe

heat death=maximum entropy no energy flows all energy gradients have been extinguished

Entropy

Disorder in the universe must always increase Burning gasoline

start of with a liquid that contains atoms arranged in long chains - fairly ordered.

When we burn it, we create a lot of heat water vapor and carbon dioxide.

Entropy

Small gaseous molecules are more disordered. They can assume more positions relative to one another than the long-chain molecules can.

Heat increases the motion of surrounding particles, making them more disorderly

Symmetry Breaking

Four dimensions out of the ten Matter-anti-matter imbalance Binding forces

strong force for protons and neutrons electromagnetic force for protons and electrons

imperfect universe-asymmetrical cracks developed into galaxies gravity forces of attraction gas-->clouds-->galaxies-->stars

The End

Big Crunch loses complexity

Big Rip loses coherence

Big Chill loses energy

Crunch vs. Chill

dark matter-attraction dark energy-repulsive

acceleration-parabolic shape

Order vs Disorder

Heat (kinetic energy)=randomness Forces pushing things together Forces pushing things apart Forces pulling things apart Forces pulling things together The ultimate tendency of the universe is toward

disorder.