According to a new study, Earth’s moon hasn’t always looked as it does today. Researchers found that around 3 billion years ago, the moon’s axis moved 125 miles or 6 degrees.
A new research published in the Journal Nature reports the discovery of a rare and never before seen event. The moon has slowly moved from its original axis about 3 billion years ago. The discovery was found thanks to ancient lunar ice, that indicates that the moon’s axis has shifter 6 degrees.
The data for the discovery was provided by NASA data that indicates lunar polar hydrogen. Matt Siegler is a planetary scientist at the Southern Methodist University in Dallas, who discovered the event with a team of colleagues.
The hydrogen in the moon is usually detected by orbital instruments, and researchers presumed it was a form of ice hidden from the sun in craters that surrounded the moon’s poles. When exposed to direct sunlight the ice tends to boil off into space, indicating a sensitive marker of the moon’s past orientation.
The offset from the moon ice was a the indicator for Siegler and his team of experts that took a closer look at NASA’s data. With a series of statistical analysis and modelling the team was able to discover that the ice that offsets from each of the moon’s pole were in the same distance but in opposite directions.
With the precise opposition, researchers were able to understand that this was an indicator that the moon’s axis, who plays the role of an imaginary pole that runs north to south through it’s middle while the moon rotates, shifted in 125 miles over the course of 1 billion years.
“Billions of years ago, heating within the Moon’s interior caused the face we see to shift upward as the pole physically changed positions. It would be as if the Earth’s axis relocated from Antarctica to Australia. As the pole moved, the Man on the Moon turned his nose up at the Earth” Said planetary scientist Matt Siegler.
This event appears as an abnormal event, given that planetary bodies settle into their axis based on their mass. Normally a planet’s heavier spots lean it towards its equator, lighter spots toward the pole. But on this rare occasion mass shifts and causes the planer to relocate on its axis, scientists are referring to this phenomenon as “true polar wander”
The polar wander explains why the moon appears to have lost much of its ice.
Source: Science Daily