Astronomy. Environmental Science. Astronomy is the science that studies the universe. Astronomy deals with the properties and laws of objects in space. The universe is made up of galaxies. There are billions of galaxies in our universe. . Our galaxy is called the Milky Way.
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Greeks developed Geometry and Trigonometry to measure planet size and distances.
Aristarchus first proposed the heliocentric model, but no one believed him.
Ptolemaic System:Ptolemy proposed a motionless earth at the center of our solar system (Geocentric) and people supported this for 13 centuries!
Retrograde motion is when the planet appears to stop, reverse its direction for a time and then resume the initial, eastward motion.
“Modern” Astronomy uses natural laws as opposed to philosophical or religious views to determine astronomical theories.
The Scientists involved in the modern Astronomical theory were from a variety of European countries.
Became interested in astronomy while viewing astronomer-predicted solar eclipse.
Persuaded King Frederick II to build observatory.
Measured the locations of heavenly bodies for 20 years.
Brahe made observations of Mars and made instruments with which to view the skies.
was more precise
than any previous
In the last year of his life, Brahe found an able assistant to continue his work: Johannes Kepler. Kepler would outshine his predecessor.
Brahe’ data did not make sense using a geocentric model. But when Keplerplaced the sun in the middle of the solar system, and suddenly the data made sense!
Kepler determined the laws of planetary motion.
Orbits sweep out equal areas in equal time intervals.
Comparing two planets:
T2 = d3
Distance in astronomical units
(1 AU = 150 million km = length of earth’s semi-major axis of its elliptical orbit around the sun)
Period in Earth years.
This force (called gravity) decreases with the square of the distance (inversely proportional).