NASA: probe will analyze asteroid that will pass close to Earth – 11/10/2023 – Science

In about five and a half years, according to astronomers’ prediction, an asteroid as large as the Empire State Building will pass through space at a distance of 31,860 km from Earth, the closest a celestial object of this size will have come to our planet. in modern history.

When that happens, it is hoped that a spacecraft launched by NASA in 2016 will be in a position to provide a detailed examination of this rare close encounter.

The mission, led by scientists at the University of Arizona, is expected to produce insights into planetary formation and knowledge that can inform efforts to build a defense system against potential asteroid collisions with Earth.

At the time of its discovery in 2004, the asteroid Apophis, named after a demonic serpent that personifies evil and chaos in ancient Egyptian mythology, appeared to pose a dire impact threat to Earth, with scientists predicting a possible collision in 2029. Since then, refined observations have ruled out any risk of impact for at least another century.

Still, its next approach in 2029 will place the asteroid at a small distance from Earth — less than a tenth of the distance from the Moon to us and well within the orbits of some of the planet’s geosynchronous satellites.

The spacecraft now heading for a rendezvous with Apophis is Osiris-Rex, which made headlines by taking a soil sample from a different asteroid three years ago and sending it back to Earth in a capsule that landed by parachute. in Utah, in the United States, in September.

Instead of retiring the spacecraft, NASA renamed it Osiris-Apex – short for Apophis explorer – and activated its thrusters to set it on course for its next target.

Apophis, oblong and shaped like a peanut, is a stony asteroid believed to be composed mainly of silicates, as well as iron and nickel.

Measuring about 340 meters in diameter, it is expected to pass within 31,860 km of Earth’s surface on April 13, 2029, becoming visible to the naked eye for a few hours, said Michael Nolan, the mission’s deputy principal investigator at the University of Arizona.

“It won’t be a glorious spectacle,” Nolan said, but it will appear as a point of sunlight reflected in the night sky over Africa and Europe.

An asteroid of this size passing so close to Earth is estimated to occur approximately once every 7,500 years. The Apophis flyby is the first encounter of its kind planned in advance.