10.1 THE EARLY UNIVERSE

EARLY IDEAS ABOUT SPACE

• Until about 100 years ago astronomers thought that outer space was unchanging.

• 1918-1929 Telescope technology improved and allowed astronomers to observe many celestial bodies that had never been seen before.

EDWIN HUBBLE

• First astronomer to identify galaxies other than our own (Milky Way)

• By 1929 Hubble had identified and estimated distances of 46 galaxies

• He noted that the galaxies were not staying still, but were moving away from each other

HUBBLE’S PROPOSAL

• Universe is expanding in all directions

• More distant galaxies are moving away faster than near by galaxies

• Expansion is accelerating

• Path of expansion can be traced backwards and galaxies appear to originate from the same location

• Hubble based his proposal on evidence from red shift analysis

RED SHIFT ANALYSIS

• Electromagnetic Radiation:

• Energy that is carried in the form of waves.

• Includes: Visable light, X-rays, radio waves, UV radiation etc.

• Stars and galaxies emit different types of electromagnetic radiation

SPECTRAL PATTERNS

• White light spits into bands of rainbow colours when it passes through a prism

• The pattern of colours is called a spectrum

• Each colour of the spectrum represents a specific wavelength

• A spectroscope is an instrument that allows the observer to see the pattern of spectral lines

• Galaxies and stars emit characteristic spectral patterns created by the elements they contain

COSMOLOGICAL RED SHIFT

• Hubble noticed that the spectrum from distant galaxies appeared to have shifted toward the red end of the spectrum.

• This change is due to a lengthening of wavelengths as the galaxy move away from the observer.

BIG BANG THEORY

• Hubble’s observations about galaxies moving apart led astronomers to hypothesize what the beginning of that process must have been

• In 1927 Georges Lemaître proposed a theory that stated the universe was formed in a single dramatic moment of expansion

• His theory was ridiculed and sarcastically nicknamed the big bang theory

• Evidence has since been collected to support this theory and the name stuck.

• Big Bang Theory: 13.7 billion years ago, a tiny volume of space quickly expanded to a very large size. In a short time, all matter and energy were formed.

THE BIG BANG THEORY EXPLAINED

• http://youtu.be/DmUiCweDic4

EVIDENCE FOR THE BIG BANG THEORY• Cosmic Background Radiation:

• Astronomers in the 60’s monitoring microwave radiation in space picked up background noise or interference. They concluded this was the left over cosmic energy from the big bang

• Radiation: the transmission of energy in waves.

• As particles of gas were created in the early universe, heat was produced in the form of microwave radiation.

• Data gathered by the Cosmic Background Explorer (COBE) and the Wilkinson Microwave Anistropy Probe (WMAP) has helped corroborate the Big Bang Theory.

WHAT WE KNOW SO FAR

• http://youtu.be/17jymDn0W6U