Cosmology Today

Cosmic Answers, Cosmic Questions

What is dark matter?

What is dark energy?

What caused inflation?

Why is there an excess of matter over antimatter

The universe is flat, 13.7billion years old , and it is composition is as follows:

The Expanding Universe

Slides based on material by Joe Mohr, Wayne Hu, Rocky Kolb and other web sites.

Modern Cosmology

Outline 1. Introduction

» From the Earth to the Universe

» 108,1013,1022,1026m

» Standard Candles and Hubble Law

2. Modern Observations» Measuring recession velocities

– Nature of light and emission– Doppler effect– Galaxy spectroscopy

» Estimating large distances– Standard candles and rods– Supernovae as standard

candles

» Results from Type Ia supernovae

4. Summary 3. Interpretation» The bad neighbor hypothesis» Homogeneous expansion

NASA Image of Planet Earth

104 kmDensity 5000kg/m3

A high density anomoly

Average density ofuniverse 10-27 kg/m3

Our Place in the Solar System

Nine planets.SUN- average low mass star, ~109m diam, 1030kgEarth orbital radius: 1011m( the only place in the universe where we know there is life.)Pluto orbit: 1013mOort Cloud: 1014m, 1011 objects

M31, the Andromeda Galaxy

If this picture were of the Milky Way, our solar system would lie here.

Our solar systemlies within theMilky Way, a gal-axy much like M31.

Nstars~1012.M~1043kgRad~10kpc=30klyDensity~10-17kg/m3

Distance~1Mpc

Telescopes are time machines!The further we look, the further we see into the past

Deep Hubble Space Telescope Image

A younger part ofthe universe.A deep image of an “empty”portion of the sky with theHubble Space Telescopereveals that the universe isfilled with galaxies- many justlike our own. The lightwe see from the most distantgalaxies has traveled approx-imately 10 billion years to reach us.

~few 1000 galaxiesdensity~10-27kg/m3