Over hundreds of millions of years, the radius of the moon has shrunk by about 50 meters (164 feet). This discovery was made by analyzing images of thrust faults (cliffs) on the moon, captured by Apollo astronauts and NASA’s Lunar Reconnaissance Probe.
Researchers found that the moon experiences shallow lunar earthquakes related to these faults. They also uncovered a partially molten inner core on the moon, measuring approximately 500 kilometers (310 miles) in diameter, less dense than Earth’s core.
The moon remains tectonically active due to its cooling and contracting interior. As the moon contracts, its fragile crust cracks and creates faults. Some cliffs on the moon are formed by these contraction-induced cracks and wrinkles.
Although Earth’s gravitational forces play a role in lunar earthquakes, evidence suggests that the moon’s contraction process is ongoing. The moon’s shrinking has minimal impact on Earth and humans, as it decreases by one quintillionth per year.
This gradual shrinkage does not affect the moon’s gravitational force with Earth, keeping it consistent. However, the moon’s retreat could disrupt ocean currents, leading to significant environmental impacts on Earth in the distant future.
Despite the potential long-term effects of the moon’s evolution on Earth, such as disrupted seasons and climate change, these changes are billions of years away. The moon’s tectonic activity could influence future lunar exploration, as shallow lunar earthquakes may affect the location of a lunar base.
This article addresses the question “Is the moon shrinking?” posed by Katrina Sherman via email. For further inquiries, contact us at questions@sciencefocus.com or connect with us on Facebook, Twitter, or Instagram.
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Source: www.sciencefocus.com
