Why is this statement true? “If we were to measure Doppler shifts in spectra of Saturn's nearly edge-on rings, we would expect to see blueshifted lines on one side of the planet and redshifted lines on the other side.

Why is this statement false? “It is easier to use parallax to measure distances to stars in distant galaxies.”

Why again is Venus's surface temperature higher than that of Mercury's?

This homework question asks us to estimate how long it would take for us to lose sight of Jupiter (at 4 AU) if the Sun were to suddenly shut off (i.e., stop shining). The problem says we can assume the Sun-Earth-Jupiter system are all aligned, for simplicity.

What does the professor mean by the “dark side of the Moon”? I said that part of the Moon never receives sunlight and got the question wrong.

Why do atoms only accept photons of particular wavelengths?

I have to compare the luminosity of two stars. One of them is twice as massive as the other and I know that L goes as the fourth power of M. There aren't enough numbers here for me to calculate the answer.

Can you go over the homework problem: Two stars at the same distance from us are the same temperature, but one is a giant while the other is a dwarf. Which appears brighter?

The Sun appears slightly bigger in the sky in January than it does in July. Given this information, for which month is the Earth moving faster around the Sun?

It doesn't make sense to me that we're located farther away from the Sun during summer than we are in Winter! Can you explain that to me?

Why is Orion considered a Winter constellation?

Why do we need to build some telescopes in space?

I don't understand how Olber's paradox tells us that the age of the Universe is finite.

How is the Milky Way's rotation curve different than that of our Solar System's?

I don't understand how if I'm standing at the equator I can see all the stars.

[lab] How do I find a star's position in my data? Can I take the maximum pixel value?

[lab] Why do we need darks and flats when observing?

[lab] How do I know what wavelength each pixel in my data corresponds to?