chapter 16 and 17: discovering galaxies the milky way galaxy

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Chapter 16 and 17: Discovering Galaxies

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Page 1: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

Chapter 16 and 17: Discovering Galaxies

Page 2: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

The Milky Way Galaxy

Page 3: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

Whenever life gets you down, Mrs. Brown,And things seem hard or tough,And people are stupid, obnoxious or daft,And you feel that you've had quite eno-o-o-o-o-ough...Just remember that you're standing on a planet that's evolvingAnd revolving at nine hundred miles an hour,That's orbiting at nineteen miles a second, so it's reckoned,A sun that is the source of all our power.The sun and you and me and all the stars that we can seeAre moving at a million miles a dayIn an outer spiral arm, at forty thousand miles an hour,Of the galaxy we call the "Milky Way".Our galaxy itself contains a hundred billion stars.It's a hundred thousand light years side to side.It bulges in the middle, sixteen thousand light years thick,But out by us, it's just three thousand light years wide.We're thirty thousand light years from galactic central point.We go 'round every two hundred million years,And our galaxy is only one of millions of billionsIn this amazing and expanding universe.

Page 4: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy
Page 5: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

Galaxies seem to take one of four different appearances

SPIRALS

Page 6: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

Galaxies seem to take one of four different appearances

BARRED SPIRALS

Page 7: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

Edge on Spiral

Page 8: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

Galaxies seem to take one of four different appearances

ELLIPTICALS

Type E0 Type E3 Type E6

Page 9: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

Galaxies seem to take one of four different appearances

IRREGULAR

Page 10: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

Galaxies that look like merger remnants

Page 11: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

Galaxy Mergers

Mergers cause the shapes of galaxies to change over time.

Page 12: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

E

CD

B

Galaxy Classification

A

F

Page 13: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

Our View of the Milky Way Galaxy

Page 14: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

Our Milky Way Galaxy?

Page 15: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy
Page 16: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

90% of a Galaxy is Dark Matter!

Page 17: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

Measuring the amount of Dark Matter in the Universe: Gravitational Lensing

Einstein’s General Theory of Relativity says that light from a distant object gets bent when it passes through a gravitational field of an intervening object.

Perfectly Aligned Slightly Misaligned

Page 18: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

Gravitational lensing

Page 19: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

Gravitational Lensing:Evidence for dark matter

Page 20: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

The Birth and Life of GalaxiesView of the Early Universe with WMAP (2003)

Early Universe showed slight variations in density!

Are the density variations the seeds of galaxy formation??

Page 21: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

Now the popular choice for galaxy formation!

Page 22: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

Young Galaxies

• smaller

• bluer

• more irregular

• higher starforming rates

Galaxies as they appeared more than 10 billion years ago.

Page 23: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

Galaxies are Grouped in Clusters

Now the popular choice for galaxy formation!

Page 24: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

The Local Group

Page 25: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

The Local Super Cluster

Page 26: Chapter 16 and 17: Discovering Galaxies The Milky Way Galaxy

Large-Scale Structure in the Universe

Superclusters, walls,and voids dominate thelarge scale structureof the Universe