Earth's newly-discovered minimoons hold mystery of ancient solar system

Earth has the existence of extra moons in its orbit in addition to the Moon we know, as per a discovery by scientists.

There are still a lot of mysteries about the solar system that scientists are working to solve. Researchers are looking to space rocks of all kinds, which might contain hints to the forgotten history of our solar system's past, to assist solve these questions.

This strategy is already showing results: Water and carbon, two of the building blocks of life on Earth, were found in October 2023 on the 4.5 billion-year-old asteroid Bennu by Nasa's OSIRIS REx mission.

According to Richard Binzel, a planetary sciences professor at the Massachusetts Institute of Technology, minimoons—tiny cosmic bodies whose orbits are partially governed by Earth and other solar system bodies—among the thousands of asteroids swarming near Earth's orbit could be excellent candidates for learning about the solar system's origins.

"[Minimoons] probably have had a bit of a pinball experience in the inner solar system, being ricocheted around and tugged on by the different planets," Binzel told Live Science. "They finally found themselves in a way that they got tugged into a somewhat circular orbit near the Earth."

Due to their relative proximity to Earth, minimoons are far easier to reach than asteroids like Bennu, requiring a lot less time and fuel to reach. While the exact origin of minimoons is still unknown, a prominent explanation points to the main asteroid belt, which lies between Mars and Jupiter.

These near-Earth asteroids, like Bennu or a minimoon, are "like time capsules," according to Paul Abell, Nasa's lead scientist for small-body exploration, who spoke with Live Science about them. "They give us indications of what the early solar system was like [and] what the conditions were."