Due to fears that that a 500-meter asteroid called Bennu could crash into Earth in the next century, NASA is set to launch a probe called OSIRIS-REx, that will approach the asteroid to study it and collect samples as part of efforts to save humanity from a possible catastrophe.
Astronomers are concerned about Bennu because a direct impact by an asteroid its size could cause “immense suffering and death” to humanity.
Astronomers have been concerned about Bennu since it was discovered in 1999, because its orbital path in space could bring it into a collision course with potentially catastrophic consequences due to the Yarkovsky effect, according to The Planetary Society.
Although scientists are unable to make precise predictions about how the Yarkovsky effect would shift Bennu’s trajectory, they believe it could tweak the asteroid’s orbital path as it passes between Earth and the moon and send it plunging catastrophically into Earth during subsequent approaches, according to Nature.
“The Yarkovsky effect describes the force that acts on a small asteroid when it absorbs sunlight and radiates it back into space as heat.”
Bennu crosses the Earth’s orbit once every six years, traveling at an average speed of about 63,000 mph. Scientists have noted since 1999 that the asteroid is getting closer to Earth. It could pass between Earth and the Moon at a distance of 290,000 kilometers in 2135 and then return 40 years later in 2175 to smash into Earth.
A direct impact with Earth could occur during subsequent approaches in 2175 and 2196 because during the expected approach in 2135 the asteroid would experience a shift in orbital trajectory, due to the Yarkovsky effect. The shift in orbital path could then put it on a collision course with Earth during the subsequent approaches.
Scientists had detected a shift in the trajectory of the asteroid in 1999 when it was estimated that it shifted by 160 km, according to Nature.
Although Bennu is not expected to pose significant threat to Earth until later in the 22nd century, NASA is taking the threat seriously. It plans to launch the OSIRIS-REx probe next month.
The probe will approach the asteroid and collect samples that will help astronomers to fine tune their assessment of the risk it poses to Earth and human civilization.
“That 2135 fly-by is going to tweak Bennu’s orbit, potentially putting it on course for the Earth later that century,” Professor Dante Lauretta, expert in planetary sciences at the Arizona University told the Sunday Times, according to the Express.
Lauretta is heading NASA’s OSIRIS-REx mission.
“We estimate the chance of impact at about one in 2,700 between 2175 and 2196,” he said.
The estimated risk is significant Professor Lauretta explained, adding that “it [Bennu] may be destined to cause immense suffering and death.”
“Bennu falls on the boundary, in terms of size, for an object capable of causing a global catastrophe,” said Professor Mark Bailey, director of the Armagh Observatory, according to the Daily Mail.
Astronomers estimate that direct impact by a 500-meter-wide asteroid could unleash destructive force equivalent to billions of tons of TNT, causing global devastation.
OSIRIS-REx probe is scheduled for launch aboard an Atlas V rocket at 7:05 p.m. EST on September 8. It is expected to arrive at Bennu in 2018 to commence a one-year study that will include collecting samples to conduct chemical, mineralogical, and geological analysis of the asteroid, according to experts.
Scientists also hope to determine from samples collected whether the asteroid contains the building blocks of biological life on Earth.
The probe will take highly fine-tuned measurements of the size and mass of the asteroid that will help scientists make an assessment of the magnitude of the Yarkovsky effect that could nudge the asteroid into a collision course with Earth.
The probe will collect samples from the asteroid while hovering over its surface. As it hovers, it will descend smoothly at a rate of about 10 centimeters per second and collect samples during a brief five-second contact with the asteroid’s surface.
OSIRIS-REx is expected to return to Earth by 2023 with vital data that could save humanity later in the 22nd century.
[Image via Dimitri Gerondidakis/NASA]