An artist's illustration shows the James Webb Space Telescope peering out into the solar system toward the asteroid belt. Ella Maru and Julien de WitEvery few years, an asteroid thats about the size of a bus strikes Earth. These rocks are much smaller than the one thatdrove dinosaurs to extinction, but they can still have a significant impact. And yet, their relatively small sizes made it difficult for surveys to spot them in advance.Now, an international team of astronomers has located more than 100 of these so-called decameter asteroids, named because they measure tens of meters in diameter, or roughly 30 to 1,600 feet across. For the study, published Monday in the journal Nature, they employed an image processing technique originally used to search for exoplanets. As a result, they spotted the smallest asteroids ever detected in the main belt, a vast field of rubble between Mars and Jupiter.These asteroid findings fill an important knowledge gap for tracing the source of meteorites and larger potentially hazardous asteroids in Earths vicinity, study co-author Richard Binzel, a physicist at MIT, tells Sky & Telescopes David L. Chandler.Compared to larger asteroids, decameter asteroids have less stable orbits, making it much more likely for them to depart from the main asteroid belt and slam against another cosmic entity, such as Earth. But even a tiny asteroid can cause real damagethe famous Chelyabinsk meteor that exploded over Russia in 2013 was a small decameter asteroid. These events can send shockwaves through entire regions, according to a statement from MIT.Ask Smithsonian: What Would Happen if a Large Asteroid Hit the Moon?Watch on Given the potential risks, NASA and collaborators like the European Space Agency (ESA) have long worked on developing an early detection system for observing and tracking asteroids. When an asteroid somewhat bigger than a cat flew over Siberia last week, the ESA was able to issue an alert around half a day in advance. While not perfect, our ability to spot asteroids before they hit is improving, astrophysicist Alan Fitzsimmons of Queens University Belfast in Northern Ireland said to New Scientists Matthew Sparkes about the recent warning.In general, the new method for spotting decameter asteroids is expected to contribute greatly toward scientists databases as they further refine these warning systems. The research team sifted through existing images of the TRAPPIST-1 star system taken by the James Webb Space Telescope, which had initially been captured to find exoplanets.The method they used, called the shift and stack technique, assembles dozens to hundreds of images of fast-moving objects. Eventually, the frames collect into a faint picture that emerges from background noise, or the other random objects that are not the subject of investigation.Usually, this would only be possible if the observer had a good idea of what orbit a certain object moves in, which isnt the case for asteroids. The MIT team was able to bypass this complication by depending on powerful computational tools designed for graphic processing to search blindly, testing every possible direction and reasonable speed for the asteroids, explains lead author Artem Burdanov, a research scientist at MIT, to Sky & Telescope. We decided to push the limits to see how faint objects we could find with this telescope.From the initial search results, Burdanov and his colleagues found more than 1,000 candidates. Then, they reviewed each image to narrow the list down, eventually confirming the discovery of 138 new decameter asteroids. And theyre hoping to find thousands more in the archives of astronomy data that have yet to be analyzed, using the same method, MIT planetary scientistJulien de Wit, a co-author of the study, tells the publication.This is a totally new, unexplored space we are entering, thanks to modern technologies, Burdanov adds in the statement. Its a good example of what we can do as a field when we look at the data differently. Sometimes theres a big payoff, and this is one of them.Get the latest stories in your inbox every weekday.Filed Under: Asteroids, Astronomy, James Webb Space Telescope, Meteors, New Research, Outer Space, Solar System, telescope