| A | B |
|---|
| Galaxies | Huge collections of billions of stars (102) |
| Galaxies are held together by | Gravitational attraction (102) |
| Period of revolution | Time for one object to travel around another (One Year) (103) |
| Period of rotation | One spin on an axis (One Day) (104) |
| Seasons | Caused by tilt of Earth's axis to sun (105) |
| Northern Hemisphere | receives direct light in summer, indirect light in winter (105) |
| Phase of the moon visible | Depends how much of sunlit side of moon we see (106) |
| Distances to stars | Measured in light years (107) |
| Distance from Earth to Sun | AU, or astronomical unit (93,000,000 miles) (108) |
