DART: Watch live the collision with the asteroid Dimorphos (VIDEO)
The first attempt at planetary defense
In about 15 hours from the posting of this article, specifically at 12:30 a.m., NASA’s Double Asteroid Redirection Test (DART) spacecraft will collide with an asteroid in an attempt to change its course. This is humanity’s first attempt at planetary defense, and it is the first attempt at a deliberate and measurable change in the motion of a body in our solar system. The purpose of the experiment is to determine whether this technique is a viable strategy to redirect asteroids that are on a collision course with Earth.
The asteroid system consists of Gemini, which is the largest with a diameter of 780 meters, and Dimorphos of 160 meters, which is in a 12-hour orbit around Gemini at a distance of 1.18 kilometers. Neither of the two asteroids poses any danger to Earth, which is why they were chosen by NASA. The fact that it is a pair of asteroids is what will allow us to measure any changes that will be achieved by the collision with the smaller asteroid.
The physics may sound simple, we hit an asteroid with enough speed to change course. But DART took 10 months to reach 11 million kilometers away from Earth. The targeting of Dimorphos will be done autonomously, using images of the asteroid as it approaches it at a speed of 24,000 kilometers per hour. The outcome of the collision is unknown and will depend on the shape, size, composition of the Dimorph and where and how hard the DART hits it.
In addition to telescopes on Earth, the collision will also be closely observed by an accompanying Italian space agency LICIACube spacecraft.
A 25 meter asteroid can cause injuries if it explodes entering the atmosphere over a populated area. Over 5 million such objects exist in the solar system and it is estimated that we have discovered only 0.4% of them.
An asteroid the size of Dimorphos would cause massive casualties if it fell to Earth in a populated area. We have found 25,000 such objects but only 39% of them are known.
Objects that will threaten human civilization are more than a kilometer in diameter and fortunately there are less than 1,000 in the solar system, and we have detected 95% of them.
You can watch the clash with Dimorphos tonight in the live stream below.
