moon

Half the Moon is always sunlit; phases are how much of that lit half we see as the Moon orbits Earth. The synodic month lasts 29.5 days, moving through new, crescent, quarter, gibbous, and full phases. Phases are NOT Earth's shadow—that's an eclipse. The Moon always shows us the same near side due to tidal locking, a gravitational dance between Earth and Moon.

Six Apollo landings returned 842 pounds of lunar material to Earth — 2,196 samples collected from six different sites across the nearside. Fifty-five years later, those rocks are still generating new discoveries, the laser retroreflectors are still in use, and the fundamental questions they raised about the Moon's violent origin have only deepened.

What causes ocean tides? The Moon's differential gravity, why there are two high tides daily, spring and neap tides, and tidal locking — explained.

Solar vs lunar eclipses: types, why they don't happen every month, the Saros cycle, famous eclipses, and how to watch safely.

The Moon's far side isn't dark — it just faces away from Earth. Tidal locking, crater asymmetry, Chang'e missions, and what's really there.

The giant impact hypothesis explains how a Mars-sized body called Theia struck the proto-Earth and formed the Moon ~4.5 billion years ago.

If the Moon vanished overnight, Earth's tides, axial tilt, and life itself would change forever. Here's the science of what happens next.

The Moon is more than a nightlight. It holds Earth's tilt steady, drives our tides, and may have made complex life possible.

July 20, 1969: Neil Armstrong and Buzz Aldrin landed on the Moon, returning 21.5 kg of lunar samples that revealed the Moon's geological history and transformed planetary science.

December 1972: Apollo 17 landed at Taurus-Littrow, returning 110.5 kg of samples and conducting 22 hours of moonwalking—the most scientifically productive lunar mission.

Apollo astronauts left reflectors on the Moon allowing scientists to measure Earth-Moon distance with millimeter precision—revealing the Moon's orbital evolution.

December 2020: China's Chang'e 5 mission landed on the Moon, collected 1.731 kg of samples, and returned them to Earth—the first automated sample return in 44 years.