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Big Bang, Black Holes, No Math ASTR/PHYS 109 Dr. David Toback Lecture 5 & 6 Prep for Today (Is now due) – L5 Reading: BBBHNM 5BBBHNM: Chap 1-4 Recommended BHOT: Chap. 1-3 SHU: Chap. 1-2 TOE: Chap. 1 eLearning Quizzes: Chapters 2-3 Reading questions Turn in now
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Today we move on to the Questions and How we go about answering them
To learn Cosmology will also need to learn a bit about:
Won’t spend too long on these, just enough to get back to the big picture…
Actually, it’s even worse
State of our understanding 2500 years ago: “The earth is, obviously, flat…”
So, how DID they figure out the earth is round?
People have been trying to understand the heavens for ages and arguing about what’s really going on…
Pumbaa: Ever wonder what those sparkly dots are up there?
Timon: Pumbaa. I don't wonder; I know.
Pumbaa: Oh. What are they?
Timon: They're fireflies. Fireflies that uh... got stuck up in that big... bluish-black... thing.
Pumbaa: Oh. Gee. I always thought that they were balls of gas burning billions of miles away.
Timon: Pumbaa, wit' you, everything's gas.
Observe that the Sun, Moon and the other “wanderers” orbit the Earth in mostly circular paths
Every so often the planets move backward for awhile, but these could be me mini-orbits way out there (epicycles)… Hmmm…
In 1514, Copernicus wrote that Planets and Earth orbit the Sun
Much simpler in some ways
More complicated in others
Earth must be rotating
The Earth isn’t at REST and rotates?
Should his view have just “been accepted”?
Perhaps his theory was just a “different interpretation” of the same data?
Need more evidence!
Need a better TOOL to test, experimentally, which is correct
Early 1600’s: Kepler and Galileo started gathering data from telescopes
Isaac Newton 1687
The history is fun, but we have a problem:
Science does not promise eternal truths
Only promises the systematic elimination of false hypotheses and the establishment of what is currently the most likely explanation of an aspect of reality…
At some point our experiments get so good that we can “observe” things that our eyes can’t see directly
What happens if the theories that explain what we can see with our eyes don’t explain what we see in a microscope?
Have to try new weirder theories
At what point do start believing there is some “truth” to the theory?