Download Name: Astronomy Study Guide Part 1 Define Astronomy

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Astronomy Study Guide Part 1
Define Astronomy- The study of all physical objects outside of the Earth
Describe the 7 Astronomers
Astronomers
What they did that was important!
Ptolemy
Geocentric
Copernicus
Heliocentric
Brahe
First true observer, had own observatory, took great observations & measurements
Kepler
Student of brahe, 3 laws of planetary motion, key here: elliptical orbits for planets!
Galileo
Many experiments, moon-craters, phases of venus, Jupiter moons, sunspots
Newton
Gravity and law of inertia
Hubble
Other galaxies outside our own
What were the two planetary models that Copernicus and Ptolemy came up with? What is the difference
between them?
Heliocentric- sun centered
Geocentric- earth centered
What keeps the planets from flying out into space? What keeps them from crashing into the sun? (2 answers)
The suns gravity keeps the planets from flying into space, the inertia of the planets keeps them from going into
the sun
How are the following defined: day, month, year, calendar, leap year
Day- 24 hours for Earth to rotate once about its axis
Month- Length of time for the moon to revolve around earth
Year- Length of time for Earth to revolve around sun 365.25 days
Calendar- years, months, and days based on our celestial objects
Leap Year- Feb 29 once every 4 years to make up for our 365.25 day solar year
Term
Cosmology
Definition
Study of origin, structure, and future of the universe
Big Bang Theory
13.7 BYA all the contents of the universe was compressed under extreme pressure,
temperature, and density in a very tiny spot
Proof that our universe is expanding:
1. Cosmic Background Radiation- left over energy from the big bang in space
2. Red-shift of galaxies
Describe how color of a star indicates temperature. Describe how stars are classified (o, g, m)
The color of a star is indicative of the temperature and the composition of a star.
For example blue stars burn the hottest of all stars. They are made up mostly of helium.
O
blue
Above 30,000
Naos
G
Yellow
5,000-6,000
Our Sun
M
Red
Less than 3,500
Betelgeuse, Antares
Absolute magnitude
Measure of the actual amount of light given off
Apparent magnitude
Measure of the amount of life as it appears from Earth
Apparent Motion
Of stars, planets, sun
Because of the Earth’s rotation the sun appears to move across the sky. Same
as with the stars.
Actual Motion
Of stars, planets, sun
Light Year
Each star is really moving in space. Because of the distance it is hard to
observe
The unit of length equal to the distance that light travels through space in 1
year
What does the sun undergo to give off its heat and energy? What does the term mean?
Nuclear Fusion- atoms of hydrogen colliding together and fusing to form helium and in the process giving off
tremendous energy!
Draw the H-R Diagram (include labels on the x and y axis). What is it and why is it important?
What is the significance of the placement of each of these on the H-R Diagram?
Describe the life cycle of our sun?
What is the definition of a Galaxy?
Large groups of stars, gas, and dust held together by gravity
List the three types of Galaxies, define each of them, and try to sketch a mini drawing for each.