The DART mission: a world first for the protection of the Earth
On September 26, 2022, NASA conducted a unique experiment by projecting its DART (Double Asteroid Redirection Test) spacecraft onto the asteroid Dimorphos at a speed of 24,000 km/h. The objective of this mission was to assess the human capacity to deflect an asteroid potentially dangerous to Earth. This kinetic impact test aimed to demonstrate a protection strategy in the event of a threat of collision with our planet.
The results were spectacular. DART succeeded in modifying the orbit of Dimorphos, reducing its rotation around its companion, the asteroid Didymos, by 30 minutes. This pioneering mission proved that it was possible to alter the trajectory of an asteroid and marked a major breakthrough for planetary defense.
A cloud of debris heading towards Earth and Mars
Upon impacting Dimorphos, DART generated a vast debris cloud consisting of rock fragments ejected into space. Among them, dozens of large blocks of rock, observed thanks to photos taken after the impact, could head towards Mars in the decades to come. These larger fragments, however, do not represent any threat to Earth.
However, the new study, accepted for publication in the Planetary Science Journalfocuses on smaller fragments, whose initial trajectories were analyzed through simulations carried out on a NASA supercomputer. These tiny debris, most measuring between 30 micrometers and 10 centimeters, are likely to enter the Earth's atmosphere or that of Mars in the coming decades.
Harmless but potentially visible fragments
Researchers estimate that if these fragments of Dimorphos reach Earth, they will not pose any no danger for the planet due to their small size. The tiniest fragments will completely disintegrate upon entering the atmosphere, creating a safe light show.
“If these fragments reach Earth, they will form beautiful streaks of light in the night sky, but their small size and speed will cause them to burn up before reaching the ground,” explains Eloy Peña-Asensio, astrophysicist and author principal of the study. The harmless nature of this debris excludes any possibility of damage or impact on the ground.
When “Dimorphids” could light up the sky
Researchers estimate that the smallest fragments, traveling at speeds of up to 5,400 km/h, could reach Earth in about seven years. However, these tiny particles are so light that they will not produce visible meteors.
On the other hand, larger fragments, traveling at a slower speed, will take longer to arrive near the Earth. According to simulations, these pieces may not reach our atmosphere for 30 years or more. If they eventually enter Earth's atmosphere, these larger pieces of debris will burn up and produce a new type of meteor shower, which researchers have already dubbed “meteor showers.”Dimorphides”.
The meteor shower caused by man: a first
If this meteor shower occurs, it will mark a unique milestone in the history of astronomy. Never before has a meteor phenomenon been triggered by human action. NASA's DART mission, first conceived as a test of planetary defense, could thus give rise to the first artificial meteor shower in history.
Although it is impossible to predict precisely when the Dimorphids will be visible, researchers hope their arrival will provide a fascinating experience for astronomers and night sky enthusiasts.
Understanding and anticipating human impacts in space
The possibility of a meteor shower caused by a human mission raises questions about long-term consequences of space activities. This study provides a first overview of the potential effects of space missions on the terrestrial and celestial environment. It also paves the way for future studies on how space missions can influence near-Earth space.
Researchers have demonstrated that even a mission designed to protect Earth from asteroids could cause changes in our celestial environment. If the “Dimorphides” occur, they will be a reminder of the extent to which human activities, even in space, can influence our cosmos.
While waiting for the eventual arrival of these fragments, astronomy enthusiasts can look forward to observing a unique meteor shower, the origin of which is believed to be the direct result of human ingenuity and space research.
