Phases of Venus

Just like the Moon, Venus has phases. It can look full, half, or like a thin crescent. You need a telescope to see these phases because Venus is so far away. When Galileo saw the phases of Venus in 1610, it helped prove that planets orbit the Sun.

How the Phases Work

Venus orbits between Earth and the Sun. When Venus is on the far side of the Sun from us, we see its full sunlit face. It looks small because it is far away. When Venus is between us and the Sun, we see just a thin crescent. But it looks much bigger because it is closer to us.

Why the Phases Matter

Galileo's discovery of Venus's phases was a big deal in science. It proved that Venus orbits the Sun, not Earth. This supported the idea that the Sun is the center of the solar system. Before this, many people believed everything orbited Earth. Venus's phases helped change how we understand the universe.

Fun Facts

• When Venus is a thin crescent, it is actually at its brightest because it is closest to Earth.
• Galileo first saw the phases of Venus through a small homemade telescope in 1610.
• Venus takes about 584 days to go through all its phases as seen from Earth.

Did You Know?

You can see the crescent shape of Venus with a good pair of binoculars. You do not always need a big telescope!