Practice Questions
1. What is the average temperature of the surface of the Sun?
2. How long does it take for light from the Sun to reach Earth?
3. Why do astronauts in the International Space Station feel weightless?
4. Where does nuclear fusion occur in the Sun?
5. One morning you see the Moon at its highest point in the sky as the Sun is about to rise. The Moon will appear as
6. What's the phase of matter in the Sun?
7. List three pieces of observational evidence for dark matter.
8. What are the axes of a Hertzsprung-Russell (H-R) diagram? On a H-R diagram, where would we find white dwarfs?
9. What's the apparent magnitude of the faintest star visible to the naked eye under the best possible conditions on Earth?
10. How old is the Sun?
11. How did the nuclear fusion reaction in the Sun start initially?
12. What is the total number of galaxies in the observable universe?
13. How does the apparent brightness of a star change with distance?
14. What is the meaning of E = mc? How can this equation be fully realized?
15. What is the Sun made of?
16. What prompted astronomers and astrophysicists to propose the existence of "dark energy" since the late 1990's?
17. What's the luminosity of a star? What's the apparent brightness of a star?
18. How does the mass of a star affect its longevity?
19. What counterbalances gravity in brown dwarfs, white dwarfs, and neutron stars?
20. What is antimatter?
21. How doe the kinetic energy of driving at 30 mph compare with driving at 15 mph?
22. Why can't the cosmic microwave background (CMB) radiation be perfectly uniform everywhere?
23. True of False: The rotation of nearly all large objects in the solar system, the Sun, the planets, and large moons go from West to East.
24. What does Hubble's Law state?
25. What is gravitational lensing?
26. One evening, at 8 PM, a crescent Moon is setting. The next evening at 8 PM, will the Moon appear smaller or larger compared with the previous night?
27. You can say we are all "star stuff" (or star dust); why is that?
28. When does a star become a main-sequence star?
29. What is the wavelength of a wave?
30. What are the major stages of life for a low-mass star?
31. What do massive-star supernovae leave behind?
32. What do white dwarf supernovae leave behind?
33. Iron is at the end of the line for nuclear fusion processes in stars. How and where are heavier elements made?
34. What's the White Dwarf limit? And what's the significance of it?
35. How does a white-dwarf supernova happen?
36. What is redshift? What is blueshift? How do you determine whether a galaxy is moving away or toward us?
37. What's a black hole?
38. What happens when an electron in an atom goes from a higher energy state/level to a lower energy state/level? From lower to higher?
39. What is the size of the event horizon of a stellar mass black hole? How does the size of the event horizon of a black hole vary with its mass?
40. Roughly how big is the Sun, a planet, a typical dwarf planet, a typical asteroid, and a typical comet?
41. The longest day in a year on Earth happens on: spring equinox, summer solstice, fall equinox, or winter solstice?
42. What observational evidence do scientists have of the existence of black holes?
43. Photon 1 has longer wavelength than photon 2. How do their energies, frequencies, and speeds compare?
44. Suppose you built a scale-model atom in which the nucleus was the size of a pea. About how big would the atom be?