EARTH & SPACE EARTH & SPACE SCIENCESCIENCE

Chapter 30 Stars, Galaxies, and Chapter 30 Stars, Galaxies, and the Universethe Universe

30.4 The Big Bang Theory30.4 The Big Bang Theory

http://watchtvbox.blogspot.com/2012/01/big-bang-theory-season-5-episode-14.html

30.4 The Big Bang Theory 30.4 The Big Bang Theory ObjectivesObjectives

Explain how Hubble’s discoveries lead to Explain how Hubble’s discoveries lead to an understanding that the universe is an understanding that the universe is expanding.expanding.Summarize the big bang theory.Summarize the big bang theory.ListList evidence for the big bang theoryevidence for the big bang theory

Hubble’s ObservationsHubble’s Observations

CosmologyCosmology is the study of the origin, is the study of the origin, properties, processes, and evolution of the properties, processes, and evolution of the universeuniverseCosmologists and astronomers can use Cosmologists and astronomers can use the light given off by an entire galaxy to the light given off by an entire galaxy to create the spectrum for that galaxy.create the spectrum for that galaxy.Edwin Hubble used galactic spectra to Edwin Hubble used galactic spectra to uncover new information about our uncover new information about our universe.universe.

http://famousscientist.net/page/4

Hubble’s ObservationsHubble’s Observations

Measuring Red ShiftsMeasuring Red Shifts Hubble found that the spectra of galaxies, Hubble found that the spectra of galaxies,

except for the few closest to Earth, were except for the few closest to Earth, were shifted toward the red end of the spectrum.shifted toward the red end of the spectrum.

Hubble determined the speed at which the Hubble determined the speed at which the galaxies were moving away from Earth.galaxies were moving away from Earth.

Hubble found that the most distant galaxies Hubble found that the most distant galaxies showed the greatest red shift and thus were showed the greatest red shift and thus were moving away from Earth the fastest.moving away from Earth the fastest.

http://www.rpdp.net/sciencetips_v2/E12B5.htm

http://en.wikipedia.org/wiki/File:Redshift_blueshift.svg

Hubble’s ObservationsHubble’s Observations

The Expanding UniverseThe Expanding Universe Using Hubble’s observations, astronomers have been Using Hubble’s observations, astronomers have been

able to determine that the universe is expanding.able to determine that the universe is expanding. The expanding universe can be thought of as a raisin The expanding universe can be thought of as a raisin

cake rising in the oven. cake rising in the oven. If you were able to sit on one raisin, you would see all If you were able to sit on one raisin, you would see all

the other raisins moving away from you. the other raisins moving away from you. Similarly, galaxies in the universe are moving farther Similarly, galaxies in the universe are moving farther

away from each other due to the expansion of the away from each other due to the expansion of the universe.universe.

http://spot.pcc.edu/~aodman/GS%20107%20web/ss%20lecture/ssindex.htm

The Big Bang TheoryThe Big Bang Theory

The big bang theoryThe big bang theory the theory that all the theory that all matter and energy in the universe was matter and energy in the universe was compressed into an extremely small compressed into an extremely small volume that 3 to 15 billion years ago volume that 3 to 15 billion years ago exploded and began expanding in all exploded and began expanding in all directions.directions.By the mid-20th century, almost all By the mid-20th century, almost all astronomers and cosmologists accepted astronomers and cosmologists accepted the big bang theory.the big bang theory.

http://www.universetoday.com/92131/why-do-we-live-in-three-dimension/

Cosmic Background RadiationCosmic Background Radiation

Cosmic Background RadiationCosmic Background Radiation Cosmic background radiationCosmic background radiation isis radiation radiation

uniformly detected from every direction in uniformly detected from every direction in space; considered a remnant of the big bang. space; considered a remnant of the big bang.

Astronomers believe that cosmic background Astronomers believe that cosmic background radiation formed shortly after the big bang.radiation formed shortly after the big bang.

The background radiation has cooled after the The background radiation has cooled after the big bang, and is now about 270°C below zero.big bang, and is now about 270°C below zero.

The Big Bang TheoryThe Big Bang Theory

Ripples in SpaceRipples in Space Maps of cosmic background radiation over the Maps of cosmic background radiation over the

whole sky show ripples.whole sky show ripples. These ripples are irregularities caused by These ripples are irregularities caused by

small fluctuations in the distribution of matter small fluctuations in the distribution of matter in the early universe, and may indicate the in the early universe, and may indicate the first stages in the formation of the universe’s first stages in the formation of the universe’s first galaxies.first galaxies.

Timeline of the Big BangTimeline of the Big Bang

A Universe of SurprisesA Universe of Surprises

Dark MatterDark Matter Analysis of the ripples in the cosmic Analysis of the ripples in the cosmic

background radiation shows that the matter background radiation shows that the matter that humans, the planets, the stars and the that humans, the planets, the stars and the matter between the stars makes up only 4% matter between the stars makes up only 4% of the universe.of the universe.

About 23% of the universe is made up of a About 23% of the universe is made up of a type of matter that does not give off light but type of matter that does not give off light but that has gravity. This type of matter is called that has gravity. This type of matter is called dark matter.dark matter.

A Universe of SurprisesA Universe of Surprises

Dark EnergyDark Energy Most of the universe is made up of an Most of the universe is made up of an

unknown material called dark energy. unknown material called dark energy. Scientists think that dark energy acts as a Scientists think that dark energy acts as a

force that opposes gravity. force that opposes gravity. Many scientists think that some form of Many scientists think that some form of

undetectable dark energy is pushing galaxies undetectable dark energy is pushing galaxies apart.apart.