what consequences? An astrophysicist from the Riviera takes part in the research mission

In September 2022, a probe sent by NASA was able to deflect the trajectory of an asteroid. Two years later, the Riviera astrophysicist Patrick Michel led the European mission responsible for studying the consequences of this collision.

It all started 2 years ago. Never seen before in the history of Humanity. A probe sent from Earth, at a speed of 2000 km/h, or 6 times the speed of a bullet, collided with an asteroid approximately 150 km in diameter, located 10 million kilometers away. This spacecraft called DART, piloted by NASA, was no bigger than a refrigerator. The celestial body struck is called Dimorphos.

Today, we must be able to draw all possible conclusions from this full-scale test in order to deduce a scientific model. For this, essential elements are missing. This is the purpose of the new mission, called HERA, one of the scientific leaders of which is the astrophysicist from the Riviera, Patrick Michel: “In fact, we don’t have the images of the ‘after’ (collision). So we need a detective who will return to the crime scene and tell us exactly what happened.”

Does this asteroid have a crater on its surface produced by the impact? If yes, what size and what depth? Or have we completely distorted the asteroid?

Patrick Michel, Director of Research at CNRS – Côte d’Azur Observatory, Côte d’Azur University

at France 3 Côte d’Azur

In order to study Dimorphos, which turned out to be the equivalent of a fragile pile of cosmic rubble, the HERA space probe was built in 3 years with on board, two small observation satellites, 2 drones ordered since the satellite. Never seen before at this distance.

According to Patrick Michel, it is the structure of the asteroid itself that is the factor that most influences the way it reacts to an impact:“We need to be able to measure its internal structures to be able to interpret”. The European Space Agency’s HERA mission will leave in October to examine it in more detail.

Although not the highest risk to Earth, compared to earthquakes or tsunamis, steroid “attacks” are very seriously considered.

What we are trying to do is to offer a robust plan to future generations to be able to face this risk the day it materializes.

Patrick Michel, Director of Research at CNRS – Côte d’Azur Observatory, Côte d’Azur University

at France 3 Côte d’Azur

Meanwhile, in a laboratory located in New Mexico, American researchers have just carried out an experiment on an asteroid 12 millimeters wide. The size of a marble. They exposed him to X-rays, “the brightest beam in the world”according to statements by the first author of the study, Nathan Moore, to AFP. Most of the energy produced by the nuclear explosion is in the form of X-rays, which means that in space, without an atmosphere, there would be neither shock wave nor fireball.

The researchers concluded that a nuclear explosion would be enough to change the course of an asteroid 4 kilometers in diameter. The model used assumes a one-megaton bomb, more than 60 times more powerful than that of Hiroshima. And which should detonate a few kilometers from its target, but millions of kilometers from Earth.

As long as you are warned sufficiently in advance!