The asteroid crash formed a tail of at least a million kilograms of rock

At the end of September, the DART (Double Asteroid Reorientation Test) space probe collided with an asteroid in the first test of a new planetary defense. The goal was to change the orbit of the space rock Dimorphos around the larger asteroid Didymus – the orbital time was shortened by 32 minutes.

introduced recently And also how much rock was shattered from Dimorphos by the impact. A thousands of kilometer tail is now following Didymus and the moon’s asteroid Dimorphos through space. The findings could help scientists better understand asteroids and provide information on how to ward off future threats.

– We think it is not less than a million kilograms, which is enough to fill six or seven train cars with gravel and material. The analysis continues. Andy Rifkin, DART senior research scientist at the Johns Hopkins Applied Physics Laboratory, who developed DART in collaboration with NASA, said during an interview. Press conference Where the results are displayed.

The Italian probe captured the collision on video

Observations of the material harvested from Dimorphos have been made by several different instruments. Among other things, with the help of the small Italian LiciaCube satellite, which accompanied Dart into space and was launched from the space probe 15 days before the collision. The cube satellite was able to take pictures of the collision site just three minutes after the collision.

The images helped scientists determine the volume of material that was shattered from the asteroid’s moon. The researchers also believe that in the images they can show how a shadow is cast on Didymus by the matter ejected from Dimorphos.

When observing the binary asteroid system from Earth, only sunlight reflected from the larger Didymos is visible. However, immediately after the collision, the discarded subjects were dominant. Comparisons of the light reflected before and immediately after the collision show that the asteroids are made of a similar material.

More research awaits with Hera

Researchers will continue to examine the new asteroid’s tail using telescopes on Earth as well as the Hubble and James Webb Space Telescopes. Dimorphos is believed to weigh about five billion kilograms, so despite the successful crash, only 0.2 percent of the rock was shattered.

The Dart was the first test of interplanetary defense — the method Dart relies on is called “kinetic impact.” The idea is that if astronomers detect a potentially dangerous asteroid colliding with it and thus speeding up its orbit around the sun — if the orbit changes enough, it could miss Earth.

How much an asteroid will be affected by a space probe impact depends on its structure. The more material ejected from the space rock in the collision, the faster it will travel.

– This is very good news for the kinetic collision method. At least in Dart’s case, kinetic collision was a very effective way to change a target’s orbit, Andy Cheng, principal investigator for Dart at the Johns Hopkins Applied Physics Laboratory, said at the news conference.

The European space probe Hera is scheduled to launch in October 2024 and travel to Dimorphos to study the collision site closely in more detail.