1Why use AU and light years?
space is big
AU = solar system
light years =starsalaxies
2What does celestial sphere do?
Mapping where things are in the sky
3What are altitude and azimuth?
altitude = up/down
azimuth = direction
4Why stars rise east and set west?
because earth rotates
5What are circumpolar stars?
Never set
Near poles
6Why constellations change?
Earth orbits the sun
7What causes seasons?
Earth's tilt 23.5*
8Why is summer warm?
More sun
longer days
9Why does the moon have phases?
We see different sunlit sides
10How long is the moon phase cycle?
About 29.5 days
11Why don't eclipses happen every month?
The moon's orbit is tilted, so alignment is rare
12What causes a solar eclipse
Moon between earth and sun
13What causes a lunar eclipse?
Earth between sun and moon
14What does retrograde motion show?
Planets appear to move backward when earth passes them
15What did jupiter's moons prove?
Not everything orbits earth
16Why was a supernova important?
Showed the sky can change
17What is parallax?
Nearby stars shift position as Earth orbits
18What does a bigger shift mean?
The star is closer
19What is kepler's 1st law?
Planets move in ellipses with sun at one focus
20What is kepler's 2nd law?
Planets move faster when closer to the sun
21What is kepler's 3rd law?
orbit period depends on distance from sun
22What's kepler's 3rd law formula for the sun?
P^2 = a^3 (P in years, a in AU)
23What can you find with it?
Orbital period or distance
24Why does a spinning object speed up when it shrinks?
Angular momentum is conserved
25Why don't planets fall into the sun?
Energy and momentum keep them in orbit
26What's the formula for light speed?
c = λf
27What happens if wavelength gets bigger?
Frequency gets smaller
28What does redshift mean?
Object moving away, wavelength stretched
29What does blueshift mean?
Object moving toward, wavelength shortened
30What happens when an object gets hotter?
It gives off more energy and peaks at shorter wavelength
31Why do hot stars look blue?
Wien's Law
32How do we find temperature from light?
Use peak wavelength (wien's law)
33How do we find speed from light?
measure doppler shift
34What are the two main telescope types?
refracting (lenses)
reflecting (mirrors)
35Why are reflector telescopes used more?
Easier to build big
Fewer issues
36Why do bigger telescopes collect more light?
Collecting area grows with size
37Why do bigger telescopes see more detail?
Better angular resolution
38Why put telescopes in space?
No atmosphere blur
Can see wavelengths blocked by air
39What are the main solar system patterns?
planets orbit same direction
same plane
inner rocky outer gas
40What are terrestrial planets like?
small
rocky
few moons
no rings
41What are jovian planets like?
big
gas/ice
many moons
rings