THE COPERNICAN REVOLUTION These Modern Times
May 15, 2015
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