Moon and Regulus

Earlier this year, a Chinese lander photographed something never before seen on the Moon: growing plants. Cotton seeds in a small chamber on the lander had sprouted, producing green leaves. Alas, the plants were doomed. They withered when night fell — and outside temperatures dropped to a couple of hundred degrees below zero.

The Moon experiences some of the wildest temperature swings in the solar system — all because the Moon doesn’t have an atmosphere.

On Earth, the atmosphere traps heat from the Sun and distributes it around the planet. So the difference between the hottest and coldest spots on Earth typically varies by a couple of hundred degrees Fahrenheit.

On the Moon, though, there’s no atmosphere to keep things in check. So at the equator, daytime temperatures peak at about 250 degrees. At night, all that heat radiates into space. As a result, the temperature around the equator can drop to almost 300 below.

The polar regions are colder. In fact, the bottoms of some craters at the poles never see sunlight. Temperatures in the craters can reach more than 400 below — as cold as Pluto. There are deposits of ice in some of those craters — possible supplies of water, rocket fuel, and more for future lunar colonies.

The Moon has a bright companion tonight. Regulus is the brightest star of Leo, the lion. It’s below the Moon at nightfall, and even closer to the Moon as they set in the wee hours of the morning.

Script by Damond Benningfield