Understanding the Phases

The phases of the Moon are the different ways the Moon looks from Earth over about a month. As the Moon orbits our planet, the Sun lights up different parts of it. The "New Moon" occurs when the Moon is between Earth and the Sun, making it invisible to us. As it moves in its orbit, we see more of it lit up—this is the "waxing" phase. After the "Full Moon," when the entire face is illuminated, we see less and less of it, which is the "waning" phase.

How Was the Moon Formed?

The leading theory is the "Giant-Impact Hypothesis." It suggests that about 4.5 billion years ago, a Mars-sized object named Theia collided with the early Earth. This catastrophic impact sent a massive cloud of debris into orbit around our planet. Over time, this material clumped together due to gravity, eventually forming the Moon we see today.

Fun Facts

• The Moon is slowly moving away from Earth at a rate of about 3.8 cm (1.5 inches) per year.
• The Moon has no atmosphere, which means it has no weather, no wind, and the sky is always black.
• Footprints left by the Apollo astronauts will likely remain on the Moon for millions of years because there is no wind or water to erode them.
• The Moon is not perfectly round; it's shaped more like an egg.