How Telescopes Changed our Understanding of the Universe

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What is the Sun made of?

Kirchhoff

Bunsen

OF THE SUN

1859

Slide 15

Confirmed: The Sun is a Star!

=

The stars are other Suns!

1863

Slide 16

Big Question 4: Where is the Sun in our Galaxy?

Is the

Solar System

at the

center of

the Galaxy?

?

Galaxy image credit: Hugo, Gaul, Block (KPNO Visitor Program), NOAO, AURA, NSF (modified)

Slide 17

Shapley observes dense star clusters . . .

Globular Cluster M13

Courtesy of Glenn Spiegelman

Mount Wilson 60-inch Reflector Telescope (completed in 1914)

Courtesy of Gale Gant

Harlow Shapley

Henrietta Leavitt

Slide 18

Location of the Sun in the Galaxy?

Galaxy image credit: Hugo, Gaul, Block (KPNO Visitor Program), NOAO, AURA, NSF - Globular cluster locations simulated

If the Sun and planets were at the center, globular clusters would be evenly distributed around us.

What did Shapley discover?

Slide 19

Location of the Sun in the Galaxy established!

Globular clusters are distributed to one side of us.

The Solar System is nearer the edge of the Galaxy!

1918

Galaxy image credit: Hugo, Gaul, Block (KPNO Visitor Program), NOAO, AURA, NSF - Globular cluster locations simulated

Slide 20

Big Question 5: One Galaxy or Many?

Is there more

than one

galaxy?

Slide 21

Distance to “nebulae” determined!

Edwin Hubble

Mt Wilson 100-inch

One of Hubble’s photographs of the Andromeda “Nebula” with Cepheid variable marked

1924

Slide 22

Revealing a universe full of galaxies

Credit: Robert Williams and the Hubble Deep Field Team (STScI) and NASA

Slide 23

Big Question 6: Did the universe have a beginning?

Did the

universe

have a

beginning?

Edwin Hubble’s data showed that the more distant galaxies are moving away faster than the closer galaxies.

Slide 24

Evidence of Big Bang detected!

1965

Slide 25