[The Epoch Times, September 30, 2022](Compiled and reported by Yi Fan, a reporter from the Epoch Times Special Department) On the evening of September 26, at 7:14 EST, a NASA spacecraft was extremely The high speed collided with an asteroid, and the spacecraft was instantly destroyed.
This is not a Hollywood movie, but a real situation in reality. The purpose of NASA’s move is to change the trajectory of the asteroid, so that in the future, if an extraterrestrial object hits the earth, the same means can be used to save the earth and human beings.
It is not without precedent that an extraterrestrial object strikes Earth. The scientific community believes that this is how the dinosaurs went extinct 66 million years ago, when an asteroid about 10 kilometers wide struck, which ended the entire dinosaur era.
The asteroid (space rock) that was hit this time, named Dimorphos, was only 160 meters wide and was traveling 11 million kilometers away when it hit.
While Dimorphos orbits the sun, it also orbits a larger asteroid called Didymos. This less common scenario is what astronomers call a “double asteroid.”
The “brothers” were carefully chosen by scientists because how much Dimorphos’ orbit around its “big brother” is deflected will be easier to monitor than its orbit around the sun.
This pair of asteroids actually poses no threat to Earth. Astronomers believe it is also unlikely that the impact would have pushed them in a path that would threaten Earth.
The spacecraft that carried out the impact mission was named DART, an acronym for Double Asteroid Redirection Test.
The DART spacecraft launched from California last November on a SpaceX Falcon 9 rocket and has spent the past 10 months orbiting the sun in order to bring its orbit closer to that of the asteroid system.
Since hitting an asteroid only changes its trajectory, it cannot be smashed into pieces. Scientists are confident that the 600-kilogram DART won’t shatter the 5 billion-kilogram asteroid, but should be enough to change its trajectory.
The timing of the impact is also important, as September 26 is relatively closer to Earth.
But colliding with an asteroid 11 million kilometers away that scientists know little about is tricky business. Mission systems engineers believe the round-trip radio signal between the DART spacecraft and the mission team on Earth will take more than a minute. The time lag means team members can’t navigate it effectively.
As DART approached Dimorphos at 22,500 kilometers per hour, it finally lived up to its expectations, operating autonomously for the last four hours of its existence, successfully locking onto its target.
As DART approached its target, its cameras returned a series of spectacular images at a rate of one per second, with rocks, boulders and smooth ground becoming visible on the peanut-like surface of the asteroid.
At the moment of the final impact, the picture disappeared. Scientists and engineers at the Johns Hopkins Applied Physics Laboratory (JHAPL) mission headquarters in the United States clapped, cheered, hugged and shook hands.
Scientists estimate that a crater 9 to 18 meters (30 to 60 feet) wide should have crashed into the surface of Dimorphos.
Observations before the collision showed that it took Dimorphos 11 hours and 55 minutes to circle its “big brother” Didymos. The DART team expects that the new orbital period after the collision will be shorter.
DART mission member Dr Harrison Agrusa said Dimorphos’ orbital period could drop by seven minutes to an hour. It depends on the density and composition of the Dimorphos, but it’s unclear. It took weeks to determine how much the orbital period changes and how effective the deflection is.
The $325 million DART mission is the first human attempt to alter the trajectory of a natural object in space.
After the test, NASA’s director of planetary science Lori Glaze said: “We are now beginning a new era of humanity — an era in which we have the ability to protect ourselves from dangerous asteroid impacts.”
Editor in charge: Lian Shuhua