Correct Answer : 6,400 km
Correct Answer : 0.384 million km
Correct Answer : Mercury and Venus
Correct Answer : cosmic rays
Cosmic rays: particles from outer space. Earth is subject to a constant bombardment of subatomic particles that can reach energies far higher than the largest machines. Cosmic rays are a form of high-energy radiation that originate from outside our solar system.
Correct Answer : Johannes Kepler
