the universe is expandingSpace Science- Chapter 4: Section 4.4

The Story of Everything

By: Neal Layton

HO

W D

ID T

HE U

NIV

ER

SE B

EG

IN? The Big Bang Theory

The Big Bang Theory

Movement in time when the universe started to expand out of an extremely hot and dense state

It is estimated that in 1 second the universe expanded from the size of a speck of dust to the size of our solar system

After the Big Bang the universe was very dense and hot

Energy and matter behaved differently because of the extreme conditions

We do not fully understand what the conditions were like in the early universe

Development of the Universe

Earliest stage of development happened in fractions of a second

Took 300,00 years for the first elements to form

Stars, planets and galaxies began to appear within the next billion years

REV

IEW

: WH

AT IS

A G

ALA

XY? All space, energy and matter

› Using your marker draw a galaxy on a balloon Draw either an irregular, spiral or elliptical

galaxy› Measure the length and width of the

galaxy using a ruler› Blow up your balloon and tie it › Measure the length and width again.

› What happened to your galaxy? The galaxy is expanding!

Movement of Galaxies

How do we know that the galaxies are moving?

Hint: The light from the galaxy is either compressing or stretching out

Astronomers use the Electromagnetic Spectrum and the Doppler Effect

Review: What is the Electromagnetic Spectrum?

Energy that travels across a distance as certain types of waves

What is the Doppler Effect?

Listen! › This is a car horn at 30/mph

http://www.physics.ucla.edu/demoweb/demomanual/acoustics/effects_of_sound/30_MPH_doppler.au

change in the observed wavelength or frequency of a wave that occurs when the source of the wave or the observer is moving

Galaxies that are moving towards Earth emit blue light because the waves are more compressed

Galaxies that are moving away from Earth emit red light because the waves are stretched out

GA

LAX

IES

MO

VIN

G A: Galaxy and Earth moving towards each otherB: Galaxy moving away from EarthC: Galaxy moving towards Earth