NASA probe Dart: Collision also changed the solar orbit of the double asteroids
The targeted collision of a space probe with an asteroid moon can change the orbit of the main asteroid around the sun. The Dart experiment has shown this.
The small Italian probe LICIACube observed the collision on site.
(Image: ASI/NASA)
When the NASA probe Dart collided with the asteroid Dimorphos, it not only changed its orbit around the second asteroid in the system, but for the first time humanity has also measurably changed the orbit of a celestial body around the sun. A research group has determined this, NASA announced today. The 770-day orbit of the double system of two asteroids was thus changed by 0.15 seconds. The speed of the asteroids on their way through the solar system changed by 4.3 cm/h, the group calculated. In parallel, another research group observed that the asteroids orbiting each other continuously exchange material and thus interact much more dynamically than previously assumed.
Helpful for planetary defense
Dart (Double Asteroid Redirection Test) crashed into the asteroid moon Dimorphos on September 27, 2022, at 01:14 AM CEST into the asteroid moon Dimorphos. A short time later, it was clear that humanity had changed the movement of a celestial body for the first time. At that time, however, it was only about the latter's orbit around its larger partner Didymos. Now it is clear that so much material was ejected from the double system that the common orbit was changed. This confirmed that a system of two asteroids can be deflected in its orbit by deflecting only one of them, according to NASA. Although the deflection sounds minimal, it could make the crucial difference in fending off an asteroid on a collision course with Earth.
The experiment was intended to practically test this very method of planetary defense. The hope is that a dangerous asteroid could be deflected by such an impact, even if only minimally, but still sufficiently far, that it would miss our home planet. Since the probe itself was destroyed on impact, ESA launched the Hera mission in October 2024. It is intended to investigate the effects of the impact on site and should then also find out exactly what consequences the uncontrollably ejected rocks had on the asteroid's orbit. It is scheduled to arrive in the system this November.
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The streaks on Dimorphos
(Image:Â NASA/JHU-APL/UMD.)
Although no probe is currently in orbit in the system, the data collected before the collision still provide exciting insights. For example, the University of Maryland announced that a research team has found evidence that the asteroids Didymos and Dimorphos continuously exchange material. They point to streak-like structures on the surface of Dimorphos, which were made visible after meticulous image processing. At first, they thought something was wrong with the camera, the university quotes study leader Jessica Sunshine. But then they realized that they fit slow impacts on the celestial body. The group explained their discovery in The Planetary Science Journal.
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