The Moon and Mercury appear to be shrinking: is our planet experiencing the same change? (photo)

Observations of various planets within and beyond our Solar System have led scientists to uncover evidence that some of these celestial bodies are decreasing in size. What is happening to them, and is this also occurring with our planet? This is discussed by IFLScience.

Mercury is Shrinking

In 1974, the Mariner 10 spacecraft flew past Mercury and found evidence that it is indeed shrinking. This evidence manifested as kilometer-high cliffs scattered across the planet. Their formation is attributed to fractures beneath the cliffs, as the smallest planet in the Solar System contracts due to the cooling of its interior.

As Mercury's interior compresses, the planet's crust gradually covers a smaller area. This occurs due to the emergence of fractures and cliffs that arise during the crust's contraction. This process can be likened to how an apple shrinks over time, developing peculiar wrinkles as it dehydrates. In other words, the apple withers, and something similar is happening to Mercury due to the cooling of its hot core.

In 2014, scientists determined that Mercury had shrunk by approximately 7 kilometers, and calculations indicated that this process began around 3 billion years ago. Only in 2023 did researchers confirm that Mercury continues to shrink today, as its core is still cooling.

The Moon is Shrinking

In 2010, scientists discovered that the Moon is also shrinking by studying the cliffs and fractures on its surface. It was found that this process is similarly caused by the cooling of the Moon's interior. Estimates suggest that over several million years, the Moon has decreased in size by about 100 meters.

In 2019, researchers found evidence that the Moon is still continuing to shrink, indicating that its crust remains under compression, and the Earth's satellite is still tectonically active.

Is the Earth Shrinking?

According to scientists, our planet is constantly gaining mass, as approximately 40,000 tons of cosmic dust and meteorites fall to Earth each year. However, at the same time, a significant amount of gas escapes from the Earth's atmosphere into space annually.

Researchers have determined that approximately 3 kilograms of hydrogen escape into space every second, leading to an annual loss of about 95,000 tons of hydrogen from Earth. Our planet also loses helium, with around 1,600 tons of this gas escaping into space each year.

By comparing these factors, as well as the rate of energy loss from the Earth's core as it cools and the amount of energy our planet receives, scientists have found that Earth's mass decreases by about 50,000 tons each year. Although this is a significant figure, it amounts to only 0.0000000000000001% of the Earth's total mass.

On the other hand, researchers have discovered that the size of the Earth decreases by about 0.1 mm annually, which is roughly equivalent to the width of a human hair. This means our planet is indeed shrinking, but not to a degree that warrants concern.