History of Astronomy. How did we get to where we are today? We stand on the shoulders of giants. Greek, Egyptian, Asian, European, Islamic, Indian scientists all observed the heavens and tried to explain what they saw What did the ancients know? And how did they know it?
Astronomical alignments built in to the pyramid
There is geometry in the humming of the strings... there is music in the spacing of the spheres.
Ptolemy attempts to explain retrograde
motion by hypothesizing that the planets
move in circles within circles…
…his theories remained in use for another
1500 years, until it became too complex to
be physically meaningful
Distances to even nearest stars are so huge, stellar parallax is a VERY small
quantity, and so could not be measured until the middle of the 19th century!
Evidence for heliocentric model existed, but was just outside our grasp to
“Absence of evidence is not evidence of absence.”
model for predicting
P2 years = a3 AU
equal areas in
Sun at one focus
measurements, not just theory…
As observed from Earth
epicycles cannot explain
the phases of Venus…
More on Newton and his Laws later…