Did DART Deflect Dimorphos? Darn Right It Did

In 2022, astronomers sent a DART into space. Their goal was to see if they could knock an asteroid headed toward Earth off its path enough to keep it from hitting our planet. Now, researchers have found that DART was a success.

The DART in question was NASA’s Double Asteroid Redirection Test. It involved shooting a spacecraft at Dimorphos, a small chunk of rock orbiting the larger asteroid Didymos. “Small” in this case still means 580 feet long and hundreds of tons. That's big enough to cause major damage should it strike Earth. There was never any danger of Dimorphos hitting our planet. But it was an ideal test subject for technology that could one day save Earth.  

The first data from DART’s collision with Dimorphos showed that the impact changed the space stone’s orbit around Didymos slightly. It was called a success. But that data wasn’t enough to show whether Dimorphos’ flight path itself changed. To learn that, astronomers had to wait. They needed to track its journey through the solar system. 

Their wait is over.

“(This is) the first time a human-made object has measurably altered the path of a celestial body around the sun,” NASA wrote in a statement. To measure the change, experts relied on data from volunteer astronomers around the world. An occultation occurs when objects pass in front of stars. When they do so, they briefly block the star's light. Star watchers look for these twinkles to track objects. By noting the twinkles caused by Didymos and Dimorphos, volunteers were able to chart its movements after the impact of DART. The verdict? Both Didymos and Dimorphos have changed their path through the solar system.   

"This study marks a notable step forward in our ability to prevent future asteroid impacts on Earth," the research team wrote in their report. It was published Friday in the journal Scientific Advances.  

Reflect: What kinds of big problems do you think science and technology should try to solve in the future?