Reacción a "Reactions to the first controlled asteroid impact"

In the early hours of 26-27 September, at 1:14 local time, NASA's DART probe collided with the asteroid Dimorphos, a rock about 160 metres in diameter that revolves around a larger asteroid called Didymos, whose diameter is about 800 metres. The separation between the two celestial bodies is about 1 kilometre. 

This is the first attempt to modify the trajectory of an asteroid in order to test a technology to protect the Earth from a possible future impact. This technology is known as "kinetic impact" and basically consists of deflecting an asteroid from its trajectory by causing a smaller object to collide with it. Of all the techniques that have been proposed to protect us from asteroid impacts, this is the simplest to implement with currently available technology. 

Neither Dimorphos nor Didymos posed a danger to us before impact, as this binary system does not cross our planet's orbit. They continue to pose no risk to Earth after the collision of the DART probe, which has a mass of almost 600 kilograms, caused a small disturbance to Dimorphos' orbit. NASA has used Dimorphos as a laboratory in which to test this kinetic impact method, in order to compare the observed results with those predicted by theoretical models. This will allow us to refine these models and thus improve this technique so that it can be used in the future in case we have to deal with an object on a collision course with our planet.  

The DART probe hit Dimorphos in the opposite direction of its motion, thus slightly reducing the speed of this asteroid and thus its radius of gyration around Didymos. Due to the gravitational interaction between the two rocks, the trajectory of Didymos has also changed slightly. The magnitude of these changes will be known in a few days (estimated to take about a week), when the effect of these changes will be noticeable. 

On the other hand, the collision has generated a crater on the surface of Dimorphos, throwing into space some of the material excavated during the formation of this new crater and exposing "fresh" materials that were initially under the surface of the asteroid. The analysis of this crater and the materials inside it is a secondary objective of the mission. 

The DART mission has thus been a major milestone in the field of planetary defence. Until now, our technology has allowed us to identify objects that are potentially dangerous for the Earth, thanks to our telescopes and the various sky-tracking programmes carried out by the various space agencies and other institutions. And it also allowed us to know whether these objects could pose a risk to us or not. But this space mission has been our first big step towards having the technology to avoid the enormous natural catastrophe that would be caused by the collision of a large celestial body with us.