Craters Of Eternal Darkness

Key Concepts:

• Craters of Eternal Darkness: Craters on the Moon, Mercury, and Ceres where sunlight never reaches.
• Tidally Locked: The state where an object's orbital period matches its rotational period, causing one side to always face the other object (e.g., the Moon and Earth).
• Lunar Maria: Dark, basaltic plains on the Moon formed by ancient volcanic eruptions, rich in iron.
• Peaks of Eternal Light: Hypothetical points on a celestial body that are always in sunlight.
• Lunar Reconnaissance Orbiter (LRO): A NASA robotic spacecraft orbiting the Moon.
• Shackleton Crater: A lunar crater near the south pole of the Moon.

Craters of Eternal Darkness

• There are 324 craters of eternal darkness on the moon.
• These craters, such as Shackleton, are deep and located near the poles, preventing sunlight from reaching their interiors.
• Craters of eternal darkness have also been found on Mercury and Ceres.
• The bottoms of these craters remain in perpetual shadow.

The "Dark Side" of the Moon

• The craters of eternal darkness are not the fabled "dark side" of the moon.
• Every side of the moon experiences both night and day.
• The moon is tidally locked to the Earth, meaning only one side ever faces Earth.
• Visually, the side of the moon that faces Earth can be considered the "dark side" due to the presence of lunar maria.

Lunar Maria

• The dark splotches on the moon, known as the "man in the moon," "moon rabbit," "lunar lady," or "sky emoji," are called lunar maria.
• Each mare is a large plain of ancient lava, rich in iron, which makes them appear darker than the rest of the moon's surface.
• 31% of the near side of the moon (the side facing Earth) is covered in maria, while only 1% of the far side is.

Peaks of Eternal Light

• Peaks of eternal light are hypothetical points on a celestial body that are always in sunlight.
• Despite the abundance of craters of eternal darkness, peaks of eternal light have not been found.
• The Lunar Reconnaissance Orbiter's (LRO) topological mapping of the moon suggests that no location on the moon has perpetual illumination.

Near-Eternal Light on Shackleton Crater Rim

• Two outposts on the rim of Shackleton Crater come close to perpetual illumination.
• These locations are blasted by the sun 94% of every lunar year.
• The only shadow that falls on either location is the shadow of the other.
• The narrator humorously describes these two locations as "jealous rocks" that prevent each other from achieving eternal light.

Conclusion

While the concept of a "dark side" of the moon is a common misconception, the lunar maria on the near side give it a visually darker appearance. Craters of eternal darkness are real features, while peaks of eternal light remain hypothetical, though some locations on the rim of Shackleton Crater experience near-constant sunlight. The LRO's data has been crucial in understanding the distribution of light and shadow on the lunar surface.