No End in Sight: The Runaway Expansion of the Universe and the

Fate of the Cosmos

By Geoff Handsfield and Orville DayDept. of Physics, East Carolina University

1 April 2008

Olber's Paradox, “The Dark Night Riddle”

Why is the sky dark at night?Consider the following:

Light radiation never terminates-- only spreads out

Trillions of stars in observable Universe.

400 billion stars in Milky Way Galaxy.

All light eventually reaches Earth.

Inside the Big Dipper

Types of Galaxies

Spiral

Disks

Elliptical

Irregular

Einstein & Relativity, Hubble & Expansion

Space-time is fabric, not void. Mass creates dimples in fabric.

Galaxies expanding away. Simplest explanation: space-time stretching.

Big Bang

Big Crunch?

Prevalent for 30 years in astronomy

Idea that Universe will collapse back to Big Bang

Relies on assumption that mass/gravitation will

eventually overpower Universal expansion.

Proven false in 1998.

The Supernova Cosmology Project

Dr. Saul Perlmutter at UC, Berkeley

Measured Red Shifts of Type Ia Supernovae (White dwarfs in binary system absorb matter until reach Chandrasekhar Limit)

Hypothesis

3 Scenarios

Expansion slowing, result in Big Crunch

Expansion slowing, result in equilibrium

Expansion speeding up, accelerating Univ.

Results

Expansion increases in time.Expansion increases in time.

Fate of the Universe-- cold death.Fate of the Universe-- cold death.

Confirmed by independent research conducted by Confirmed by independent research conducted by rival team, High-Z Supernova Search Team.rival team, High-Z Supernova Search Team.

Big Crunch unlikely.Big Crunch unlikely.

Cause of the Expansion- Dark Energy

Energy counterpart to dark matter.

Source of dark energy unknown.

Opposite force to gravitation.

Exhibits properties of negative pressure.

As Universe expands, more dark energy seeps into all space, providing more anti-gravity.

Fate of the Universe

Observable Universe increases in time. Objects in observable Universe decreasing. Fewer interactions with celestial bodies. Ultimate destruction by black holes at center of

galaxies. Black holes ultimately evaporate by Hawking

radiation. Universe a lonely place-- average density drops

toward zero. Only stray particles remain.

Olber's Revisited

Finite Age of Universe

Finite Speed of Light

Accelerated Expansion of Universe

Stretching of Space-Time

Sources

Bennett, Donohue, Schneider, Voit. The Cosmic Perspective.

Goldsmith. The Runaway Universe. Harrison. Cosmology. http://www.nasa.gov/images/content/152808main_

RSoph_full.jpg http://www-news.uchicago.edu/releases/03/darkm

atter0903.jpg http://www.theonlinecandyshop.com/ProductImag

es/CRUNCH.jpg http://preposterousuniverse.com/spacetimeandgeo

metry/covercrop.jpg http://z.about.com/d/physics/1/0/r/-/-/-/BlackHole.j

pg