
Age: 4.543 billion years
The Earth's climate has changed throughout
history. Just in the last 650,000 years there have been seven cycles of glacial
advance and retreat, with the abrupt end of the last ice age about 7,000 years
ago marking the beginning of the modern climate era — and of human
civilization. Most of these climate changes are attributed to very small
variations in Earth’s orbit that change the amount of solar energy our planet
receives.
Radius: 3,959 mi
Mass: 5.972 ×
10^24 kg
Area: 196.9 million mi²