Like Earth, Mars formed about 4.5 billion years ago. The history of Mars has four geological periods. These are the Amazonian (from today back to 3 billion years), the Hesperian (3 billion to 3.7 ...

The valleys get their name from Mariner 9, which became the first spacecraft to orbit another planet when it arrived at Mars in 1971. About 4.5 billion years ago, Mars coalesced from the gaseous ...

Precambrian time covers the vast bulk of the Earth's history, starting with the planet's creation about 4.5 billion years ago and ending with the emergence of complex, multicelled life-forms ...

When the moon first formed 4.5 billion years ago—and was much closer to Earth—a day on Earth lasted about 10 hours. The cause of the pause, say the scientists, was a natural resonance between ...

Saturn's rings, once thought young, might be as old as the planet itself, around 4.5 billion years ... between 100 million and 400 million years ago. New studies, however, suggest that these ...

Narrator: 4 and a half billion years ago, clouds of cosmic dust and gas which ... The planet Earth is about 4.5 billion years old. Earth spins at 1000 miles per hour. It takes 24 hours to complete ...