Researchers at the Massachusetts Institute of Technology (MIT) have developed an innovative method to identify medium-sized asteroids in the asteroid belt. Thanks to this approach, they managed to detect small rocks within a region full of giant debris. Published in the magazine Naturethis achievement represents progress in protecting the Earth from the possible arrival of a dangerous asteroid.
The method consists of a reinterpretation of the technique used by astronomers to detect exoplanets light years away. They took the data from the James Webb Space Telescope that originally looked at the Trappist-1 planetary system and separated out the noise the instrument found. In those glimpses, astronomers captured some asteroids close to Earth in an accidental way. MIT experts, applying filters and using advanced graphics processing units (GPUs) on 10,000 James Webb photographs, managed to increase the infrared glow that asteroids naturally emit.
This unique indirect method allowed 138 small rocks to be found. Until now, the minimum size of an asteroid identified in this region was one kilometer. Identifying these asteroids has been a challenge due to the enormous distance between the asteroid belt and Earth. According to NASA, the debris ring is between 2.2 and 3.2 astronomical units away. An astronomical unit is the distance from the Earth to the Sun or its equivalent, 150 million kilometers.
“We thought we would only detect a few new objects, but we detected many more than expected, especially small ones. “It is a sign that we are probing a new population regime, where many more small objects are formed through cascades of collisions that are very efficient at breaking up asteroids below about 100 meters,” said Julien de Wit co-author of the study.
Large asteroids, tens of kilometers long, tend to terrify most people. The fear is justified because one of them was responsible for the extinction of the dinosaurs in the Cretaceous period 66 million years ago. However, the asteroids that really worry scientists and governments are the medium ones, tens of meters long.
These medium-sized space rocks keep space monitoring systems on alert. Due to their size, they are virtually undetectable until it is too late. Despite scientific efforts, it has been impossible to record all the bodies that are near the planet. Furthermore, the “factory” that produces them is very close, in the asteroid belt between Jupiter and Mars.
You don’t have to go far back in time to see the consequences of a medium-sized meteorite. In 2013, a 20-meter bolide crossed the sky over Chelyabinsk, Russia. The space rock fragment did not impact the ground, but exploded in the sky with a force of 500 kilotons. Its blast wave broke windows and caused significant damage; 1,500 people were injured and 3,600 buildings were affected. This Russian event was a reminder of how dangerous unidentified medium-sized meteorites can be.
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