Astronomy

Front 1

The systematic study of the properties and evolution of stars, galaxies, and the universe is known as

Back 1

astronomy

Front 2

Kepler proposed that

Back 2

planets move in elliptical orbits

Front 3

an astronomical unit (A.U.) is defined as

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the distance between the earth and sun

Front 4

Aristarchus used the size of the earth's shadow to compute

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the distance to the moon

Front 5

A cosmology with the earth at the center of the universe is said to be

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geocentric

Front 6

Kepler's 3rd law states that

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there is a relationship between a planet's sidereal period and distance from the sun

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Ancient astronomers considered planets different from stars because

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planets move through the stars on the celestial sphere

Front 8

In chico at local noon on the autumnal equinox the sun was

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on the celestial equator

Front 9

The approximate angular diameter of the sun is

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0.5 degrees

Front 10

Eratosthenes used the altitude of the sun in Alexandria and Syene to compute the

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diameter of the earth

Front 11

with respect to the stars on the celestial sphere the sun

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moves west to east

Front 12

The moon may have a magnitude of -11 while Mars' magnitude may be around -1. the ratio of light energy recieved by your eye between the Moon and mars is about

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10^4:1

Front 13

In the original Copernican model of the solar system

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the earth orbits the sun on a circular orbit

Front 14

By the year 100 BC astronomers had a reasonable understanding of many things. Which of the following did they NOT know?

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Mass of the earth (they knew the diameter, distance from earth to moon, and diameter of sun)

Front 15

The path of the sun on the celestial sphere is known as the

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ecliptic

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Saturn at opposition sets at

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sunrise

Front 17

Proofs used by Aristotle to demonstrate the earth is spherical

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1. If a ship sailed into the horizon, it looks like it sinks because it just disappears. However if the ship returns it obviously did not sink which would mean the earth had to be round. If it was flat then you would be able to see it it would just get smaller and smaller.
2. Travel North of Greece stars that you can see in Greece you cannot see up North. So if the earth was flat you wouldnt lose/gain stars.
3. Lunar eclipse- shadow of the earth on the moon was always circular
4. if you traveled east to India there are elephants and if you travel South to Africa there are elephants.

Front 18

Explain Occam's razor and how it applied to the physical sciences

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**Occams razor is choosing the easier way of two explanations. The Copernican theory was chosen since it was more simple than the geocentric model

Front 19

Hipparchus was one of the greatest pre-telescope astronomers. List 2 of his accomplishments

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1. Trigonometry
2. Magnitude scale (Brightest star=first magnitude, 2nd Brightest=2nd magnitude, etc.)

Front 20

List one observation made by Galileo that supported the Copernican model

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Jupiter had 4 moons orbiting it, not the earth. Venus had phases that proved it orbited the sun and not the earth

Front 21

List 2 Aristotelian concepts about the physical world that were accepted until the 16th to 17th centuries

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1. If the earth was moving, objects in the sky would fall backward and behind the speed of earth
2. The heavens were perfect and unchanging

Front 22

motion of the celestial sphere

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daily 24 hour east to west

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motion of sun

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year 1 degree/day west to east

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motion of moon

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monthly 12 degree/day west to east

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O with a + in the middle

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earth; circular orbit; uniform speed

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O with a . in the middle

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sun

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New moon

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rise: sunrise; set: sunset

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1st Quarter

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rise: noon; set: midnight

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Full moon

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rise: sunset; set: sunrise

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3rd Quarter

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rise: midnight; set: noon

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scaler

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magnitude and unit

Front 32

vector

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magnitude, unit, and direction

velocity- m/s
acceleration- rate of change of velocity. (m/s)/s or m/s^2

Front 33

newtons first law

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constant speed in a straight line unless affected by an outside force (velocity)

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newtons second law

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force= (mass) x (acceleration)

Front 35

Thales (600-700 BC)

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Knew the ecliptic; length of a year

Front 36

ecliptic

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path of the sun

Front 37

Pythagoras (500 BC)

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Cosmos were perfect (unchanging); earth was imperfect; sphere is the perfect shape

Front 38

Anaxagoras (420 BC)

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Phases of the moon
-moon orbits the earth
-reflecting sunlight (not glowing)
Measured distance and size of sun (using 2 points on the earth to try to calculate, he was wrong because he thought the earth was flat so he didnt use an angular scale.)

Front 39

Reason why we can see lighted parts of moon

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has to do with angle of moon compared to sun compared to earth

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Aristotle (300 BC)

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Earth is a sphere (4 proofs)

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Aristarchus (250 BC)

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Distance and size of the moon
moon= 1.5 degree he was off by 1 degree
AU (Astronomical Unit) distance from earth to sun

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Eratosthenes (200 BC)

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earth calculations (ex diameter 1% error)

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Hipparchus (150 BC)

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1. Trig
2. Systematic observations
3. Used old observations and compared them to his own. Discovered Precesion (time frames for things like Halie's comet that happens every 80 years).
5. Magnitude Scale Big-Alpha Little-beta
6. Distance to Moon (29.5 earth diameters)
7. Length of a year (error ~7-15 minutes)

Front 44

Ptolemy (150 AD)

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Geocentric- earth is center

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Copernicus (1540 AD)

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Heliocentric- sun centered
Inferior- sun to the moon
Superior- earth and what is past it
Synodic Period- planet relative to sun (time)
Siderial Period- True measurement of time

Front 46

Kepler

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1. The path of the planets about the sun are elliptical in shape, with the center of the sun being located at one focus. (The Law of Ellipses)
2. An imaginary line drawn from the center of the sun to the center of the planet will sweep out equal areas in equal intervals of time. (The Law of Equal Areas)
3. The ratio of the squares of the periods of any two planets is equal to the ratio of the cubes of their average distances from the sun. (The Law of Harmonies)

Front 47

Galilao

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-used telescope
1. Jupiter has moons
2. Sun spots
3. Lunar Topagraphy (mountains on moon, etc.)
4. Phases of Venus
*Not perfect (perfect shape but imperfect surfaces)

Front 48

Newton

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Law of motion
*vectors