Select the correct term to complete the sentences.
speed of light
1. Every particle of matter has a(n) ____ twin.
2. ____ is equal to 3 × 108 meters per second.
3. ____ is a theory that describes what happens to matter, energy, time,
and space at speeds close to the speed of light.
4. An effect known as ____ causes time to move more slowly for an
object in motion than for one at rest.
5. According to ____ the force we call gravity is an effect created by the
curvature of space and time.
6. The perspective of an observer from which the position and motion of
a system can be described is called a(n) ____.
7. A(n) ____ is an object with such a strong gravity that its escape
velocity equals the speed of light.
8. According to the ____, the universe was once smaller than an atom
and began to expand after a huge explosion.