The Big Bang! The Big Bang! (pg 20)(pg 20)

OriginsOrigins How did the:How did the:

Universe form?Universe form?

Solar system / Earth form?Solar system / Earth form?

How Do We Know?How Do We Know?

Origin of the Origin of the UniverseUniverse

Big BangBig Bang - - model for beginning of the universemodel for beginning of the universe ~~15 billion years ago15 billion years ago

Expansion from a hot dense state into a vast much Expansion from a hot dense state into a vast much cooler cosmoscooler cosmos

What did it look What did it look like?like?

Expansion from a hot dense state into a vast Expansion from a hot dense state into a vast much cooler cosmosmuch cooler cosmos

http://rainbow.ldeo.columbia.edu/courses/v1001/7.html

- infinitely dense point not governed by our physical laws or time

- all matter and energy contained in one point

Building a UniverseBuilding a Universe

http://rainbow.ldeo.columbia.edu/courses/v1001/7.html

• Instantaneous filling of space with all matter• As matter filled space it began to rapidly cool.

Building a UniverseBuilding a Universe

As things cool they move from gas to liquid As things cool they move from gas to liquid to solid. Think about water as it cools from to solid. Think about water as it cools from

steam to water to ice.steam to water to ice.

Continuing Continuing expansionexpansion

Edwin Hubble:Edwin Hubble:Evidence of the Universe continuously Evidence of the Universe continuously

expandingexpanding

Doppler shifting - wavelength emitted by something moving away from shifts to a lower frequency – or Red Light Visible wavelengths of

light emitted by objects moving away from us are red

The faster the object is moving, the redder the light

THE DOPPLER EFFECT

Hubble’s Evidence – The Red Hubble’s Evidence – The Red Shift caused by the Doppler Shift caused by the Doppler

effecteffect When we observe distant galaxies, they appear to give off red light. This means they are moving away from us = universe is expanding.

The faster they move away from us, the more they are red shifted. We can measure the speed of an object by

the wave length it emits This is the principal by which radar guns measure

the speed of a car or baseball Sound of a fire truck siren - pitch of the siren

is higher as the fire truck moves towards you, and lower as it moves away from you

Where else to you HEAR the Where else to you HEAR the Doppler effect?Doppler effect?

Sound of a police car’s siren Pitch of the siren is higher as the fire

truck moves towards you, and lower as it moves away from you

Features of Our Solar Features of Our Solar SystemSystem

Orion Spiral arm of the Milky Way Galaxy

Our Sun and our 8 planets (sorry Pluto) 172 known moons (satellites) orbiting

planets or other objects (dwarf planets) 2 Different asteroid fields

One is in orbit the Sun between the orbits of Mars and Jupiter and the other is the Kuiper belt at the edge of the solar system

Interplanetary dust and gases A huge amount of Comets (from the

Kuiper belt, mainly)

Relative Sizes of the Relative Sizes of the Sun and PlanetsSun and Planets

Solar System Solar System ConfigurationConfiguration

Origin of Our Solar Origin of Our Solar SystemSystem

Origin of Our Solar Origin of Our Solar SystemSystem

Solar nebula theorySolar nebula theory

The cloud begins to The cloud begins to rotate and forms a disk. rotate and forms a disk. The rotation causes The rotation causes gravity to get intense.gravity to get intense.

Gravity causes the Gravity causes the matter in the cloud to matter in the cloud to condense and eventually condense and eventually collapse creating collapse creating immense pressure.immense pressure.

A A solar nebulasolar nebula is formed is formed There is an embryonic Sun at the center There is an embryonic Sun at the center A rotating cloud surrounds the sunA rotating cloud surrounds the sun

Cloud of gases and dustCloud of gases and dust

large currents of gas and dust remain far large currents of gas and dust remain far from the protosun (the center)from the protosun (the center)

Embryonic Sun and Embryonic Sun and Rotating CloudRotating Cloud

planetesimals have formed in the inner solar planetesimals have formed in the inner solar systemsystem

The PlanetsThe Planets Terrestrial Planets: Terrestrial Planets: small, composed of rock, with small, composed of rock, with

metal coresmetal cores

Mercury Mercury VenusVenus EarthEarth Mars Mars

Jovian Planets: Jovian Planets: large, composed of hydrogen, large, composed of hydrogen, helium, ammonia, methane, relatively small helium, ammonia, methane, relatively small rocky coresrocky cores Jupiter Jupiter SaturnSaturn UranusUranus NeptuneNeptune

– Pluto?

ReviewReview

ReviewReview When did the Universe begin?When did the Universe begin? What is the name of the theory describing how the What is the name of the theory describing how the

universe began?universe began? What happens to the temperature of matter What happens to the temperature of matter

(gasses, liquid, etc.) as it expands?(gasses, liquid, etc.) as it expands? Describe the universe just before the big bang.Describe the universe just before the big bang. How can we tell the universe continues to expand?How can we tell the universe continues to expand? Give an example of where you can see or hear the Give an example of where you can see or hear the

Doppler effect.Doppler effect. What occurs in each of the three steps in the What occurs in each of the three steps in the

Nebular Theory?Nebular Theory?