Produced by: Tarun Mishra Designed by: Manoj Kumar
For nearly 40 years, scientists believed the Moon was formed from debris after a collision between a young Earth and another object. However, a new study from Penn State researchers suggests that the Moon might have been a captured space object.
Lunar soil samples collected during the Apollo missions (1969-1972) revealed that the Moon's composition was similar to Earth's, supporting the impact theory that dominated scientific discussions, especially after the 1984 Kona Conference.
Researchers Darren Williams and Michael Zugger propose an alternative explanation, suggesting that the Moon was originally part of a binary system. Earth's gravity captured one of the objects, while the other was repelled.
A key argument supporting the new theory is the Moon's orbit, which is not aligned with Earth's equator. A Moon formed from a planetary collision would likely orbit above the planet's equator, but instead, it orbits in a different plane more aligned with the Sun.
The researchers draw a parallel with Neptune's largest moon, Triton, which is believed to have been captured from the Kuiper Belt. Similar binary-exchange processes may have occurred in the case of Earth's Moon.
Williams and Zugger suggest that when the Moon was first captured, its orbit was an elongated ellipse. Over time, tidal forces caused the orbit to become more circular, as observed today.
The researchers calculated tidal changes and orbital dynamics to support their theory, showing how the Moon's orbit evolved over thousands of years as a result of gravitational interactions with Earth.
This study adds to the ongoing debate about the Moon's origin, presenting a compelling alternative to the collision theory and challenging long-held scientific assumptions about how Earth's satellite was formed.