Moon Crater Traced as Origin of Nearby Asteroid

Scientists have long been able to trace many asteroids back to their parent bodies, whether planets or moons. However, they now assert for the first time that they’ve pinpointed the exact crater on the Moon where an asteroid originated from.

Craters serve not only as the remnants of asteroid impacts on celestial bodies like planets or moons but also as the potential origin sites for new asteroids. When an impact is forceful enough, it can launch rock fragments into space, where they may linger as asteroids for countless years until encountering another object, potentially initiating a new impact cycle.

Scientists can often determine the parent body of an asteroid by analyzing its composition, reflectivity, and other characteristics. However, pinpointing the exact location of its origin on those celestial bodies has been a challenge until now.

Investigating the Lunar Origins of Kamo’oalewa

Kamo’oalewa, discovered in 2016, is an asteroid with a diameter ranging from about 46 to 58 meters (150 to 190 feet) and is classified as a “quasi-satellite” of Earth. Although it orbits the Sun, Earth’s gravitational influence prevents it from straying too far from our planet. A 2021 study suggested that it likely originated from the Moon based on its reflective properties and orbit.

Now, an international team of scientists has further refined its origin. Through impact and dynamical modeling, they determined that an asteroid impact on the Moon with a diameter of at least 1 km (0.6 miles) and resulting in a crater larger than 20 km (12.4 miles) would have been necessary to launch a rock fragment like Kamo’oalewa into space. This event would have occurred relatively recently, within the last few million years, for Kamo’oalewa to still exist.

The researchers scanned numerous craters on the lunar surface and identified one that matched the estimated age and size requirements: Giordano Bruno. On the far side of the Moon, Giordano Bruno measures approximately 22 km (14 miles) wide and dates back to around 4 million years.

Potential Multi-Fragment Event of Kamo’oalewa’s Lunar Origin

During this event, it’s probable that Kamo’oalewa wasn’t the sole fragment ejected. The team estimates that over a thousand pieces of debris, each measuring dozens of meters wide, would have been propelled into space.

“Although the majority of this debris would have fallen to Earth as lunar meteorites within a span of less than a million years, a few fortunate objects may persist in heliocentric orbits as near-Earth asteroids, awaiting discovery or identification,” explained Yifei Jiao, the study’s lead author.

There’s a possibility that we’ll gain a closer understanding of Kamo’oalewa soon. China has designated this small asteroid as the target for its forthcoming Tianwen-2 mission, which aims to retrieve samples for analysis back on Earth. If indeed derived from the Moon, the samples collected should originate from depths beyond those reached by previous lunar missions.

“It will provide a unique perspective compared to any existing specimens – a crucial piece of the puzzle in our quest for understanding,” remarked Erik Asphaug, a co-author of the study.

Read the original article on: New Atlas

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