THE COPERNICAN REVOLUTION

These Modern Times

Fast Forward….

Over time, the Protestant Reformation lessened the power of the Catholic Church

Fast Forward….

The work of Copernicus, Brahe, Kepler, Galileo and Newton was accepted

Uniting the sciences

Newton united physics and astronomy through his laws of motion Inertia explains why planets (and others)

stay in motion Law of gravitation explains why things stay

together

The apple hit me on the head!

LOL!

Uniting the sciences

Fraunhofer united chemistry and astronomy The spectral lines from sunlight tell what

elements are present

But I didn’t know what

they meant. LOL!

Charles Messier (1730-1817) French astronomer Was looking for

comets Kept being

distracted by other fuzzy objects

Published catalogue of 103 “nebulae” (later expanded to

110)

I only found 13 comets.

LOL?

William Herschel (1783-1822) Musician, composer, and astronomer Discovered Uranus

First planet discovered since ancient times First planet discovered with a telescope

Discovered that the solar system was moving

I can see Uranus!

LOL!

William Herschel

Discovered that the solar system was moving

Mapped the visible stars and discovered the galaxy is disk shaped

Discovered infrared light in sunlight

Infrared is hot stuff!

LOL!

Caroline Herschel (1750-1848)

Discovered many comets and nebulae

Produced an accurate and usable star catalog

First woman member of Royal Astronomical Society

I looked at more than Uranus!

LOL!

Questions

Who unified physics and astronomy? Newton

Who published a catalogue of 110 fuzzy objects? Messier

What is William Herschel known for? Discovered : Uranus, disk shaped galaxy,

infrared light in sunlight Who was the first woman member of

Royal Astronomical Society Caroline Herschel

Urbain Le Verrier (1811-1877) United mathematics and

astronomy Noticed that Uranus had slight

deviations in its orbit Predicted that another planet

was out there Neptune was within 1º of his

prediction First planet discovered using

math

I got the credit! LOL!

Cincinnati Observatory

First observatory built in US

Founded 1842, first operation in 1845

I’m going to look for Uranus!

LOL!

Maria Mitchell (1818-1889)

Discovered many comets First professor of astronomy at VassarDon’t mess

with my money!

LOL!

Photography

Biggest advance since the invention of the telescope

Showed things too faint to see with the eye

Made more accurate observations than sketches

Questions

What did LeVerrier use to discover Neptune? Mathematics

Where was the first observatory founded in the US? Cincinnati

What is Maria Mitchell known for discovering? Comets

What is the biggest advance in astronomy since the telescope? Photography

Henrietta Swann Leavitt (1868-1921) Worked as a computer at Harvard Worked to determine the magnitudes of

stars Used photographs of night sky Wasn’t allowed to operate a telescope

Discovered more variable stars than anyone else

Cepheid Variables

Leavitt plotted the variable period to the absolute brightness

Discovered direct relationship

Enabled astronomers to determine distance Dimmer the star = further

away Mathematical relationship

WHAT?!?

Size of the universe…

By early 20th century, a debate was raging.

Was the galaxy the extent of the universe or were there others?

Those blobs..

Astronomers were intrigued by certain nebulae

Were they dust clouds in the Milky Way or other galaxies?

Edwin Hubble (1889 – 1953)

American astronomer Observed using the

100 inch Hooker Telescope at Mt. Wilson Observatory

Wanted to settle the issue of the universe’s size

Studied the Andromeda Nebula

100 Inch Hooker?

LOL!

Edwin Hubble

1923: studying photographic plates of Andromeda

Discovered a Cepheid Variable!

Could determine distance!

Andromeda was a galaxy!

Questions

Who discovered the relationship between variable period of stars and their absolute brightness? Henrietta Swann Leavitt

What was the big debate in astronomy at the turn of the 20th century? Was the universe bigger than the Milky Way

Galaxy? What did Hubble find that proved Andromeda

was another galaxy? Cepheid variables

Not only is the universe bigger… Hubble observed that the galaxies were

moving away So the universe is not only bigger than

thought, it’s getting bigger

Run that tape backwards…

If the universe is expanding, it used to be a LOT smaller

Universe believed to have started with Big Bang

Albert Einstein (1879-1955)

1905: Special Relativity

Time is not constant, only the speed of light is constant

Energy is equal to mass times the speed of light squared: E=mc2

Explains how stars work

It’s all relative.

LOL!

Albert Einstein

1916: General Relativity Space + time = spacetime Mass warps spacetime The warping of spacetime is gravity

Questions What else did Hubble discover about the

universe? It is expanding

What did Einstein's theory of Special Relativity explain? How stars work

What did Einstein’s theory of General Relativity say warped spacetime? Mass

What did Einstein’s theory of General Relativity say could be bent by warped spacetime? Light

Proving general relativity

Einstein predicted that the Sun’s gravity would bend the light of stars behind it

During an eclipse would stars would appear out of place

Confirmed by Eddington in 1919

Stephen Hawking (1942-)

Theoretical Physicist Theories about black

holes before they were proven to exist

Theories about the early universe

United astronomy with theoretical physics

Nobody knows my real voice.

LOL!

The digital revolution

Computers are the biggest contribution to astronomy since photography Modeling, image

manipulation, telescope control etc.

Digital photography gives better imaging than ever Back to amateurs

New age of telescopes

Telescopes now use all bands of the spectrum

Telescopes can adapt to focus more precisely

Bigger telescopes than ever!

New age of telescopes

NASA’s Great Observatories Program Compton: Gamma Ray Chandra: X-Ray Hubble: Visible Spitzer: Infrared

What next?

The more we learn, the more questions we have.

The revolution continues

Viva la revolucion!

Questions

How was General Relativity proved? Light from stars behind the Sun was seen

to have moved during an eclipse Who united astronomy and theoretical

physics? Stephen Hawking

What’s the biggest advancement in astronomy since photography? Computers