For the first time, humans have changed the path of an asteroid around the Sun
NASA did not just nudge an asteroid's moon. Its 2022 DART crash also shifted the path of the entire asteroid pair around the Sun, a new study confirms.
In 2022, NASA deliberately crashed its DART spacecraft into Dimorphos, a small asteroid moon about 170 meters wide.
Dimorphos orbits a larger asteroid called Didymos, about 805 meters wide. Neither posed any threat to Earth.
The goal was to test whether hitting an asteroid could change its course, in case one ever heads our way.
Earlier studies showed the impact shortened Dimorphos' 12 hour orbit around Didymos by about 33 minutes.
Now researchers led by Rahil Makadia at the University of Illinois Urbana-Champaign have found a second effect.
The crash also changed the orbit of the whole Didymos system around the Sun.
The pair takes about 770 days to circle the Sun. The impact changed that by about 0.15 seconds.
Its speed changed by about 11.7 microns per second, or roughly 4 centimeters per hour.
That sounds tiny. But over years, even small changes can add up to a big difference in where an asteroid ends up.
The team used radar and telescope data, plus 22 observations by volunteer astronomers who timed the asteroid passing in front of distant stars.
Debris blasted off the asteroid roughly doubled the push from the spacecraft alone.
The data also suggest Dimorphos is slightly less dense than thought. It may have formed from material shed by a fast spinning Didymos.
Why does this matter? It is the first direct measurement of a human made change to an asteroid's orbit around the Sun.
There are caveats. The change is extremely small and was measured from Earth using indirect methods.
ESA's Hera mission, launched in 2024, will study the asteroids up close and measure the impact's effects more precisely.
RESEARCH PAPER
Rahil Makadia et al., "Direct detection of an asteroid's heliocentric deflection: The Didymos system after DART," Science Advances (2026).
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