Saving Earth has an unexpected effect: craters on neighboring planet Mars

Saving Earth has an unexpected effect: craters on neighboring planet Mars

Oops! For the first time, humanity itself has created a swarm of space boulders. These could impact Mars in thousands of years, Italian researchers calculated. The Earth remains out of harm’s way, but the artificial meteor shower does raise questions: who is responsible for damage?

On September 26, 2022, the NASA spacecraft DART (Double Asteroid Redirect Mission) hit Dimorphos head-on, a lump of space rock 177 meters in diameter. The aim was to see whether in the future an asteroid hurtling towards Earth could be knocked out of its orbit with a strong impact.

That worked: the push that Dimorphos received from the impact was beyond expectations, as measurements afterwards showed. But the collision also had an unexpected effect. In images from the Hubble Space Telescope after the impact, astronomers saw 37 space boulders of up to about 7 meters that had been knocked loose by the collision.

Marco Fenucci of the space agency ESA and a colleague wondered what would eventually happen to this swarm. “We wanted to see if these stones could be intercepted by Earth or by Mars,” says Fenucci on the phone. Using specialized software, they projected the swarm’s trajectories about 20,000 years into the future. Result, published on the preprint website Arxiv.org: they will not cross the Earth’s orbit, but they will cross that of Mars, in about six thousand years, and again in twenty thousand years.

An impact on Earth would burn up rocks of this size in the atmosphere, says Fenucci, “but for Mars it’s a different story because the atmosphere is much thinner. They will hit there and cause craters.”

Ethical and legal issue

It is impossible to calculate whether and when this will actually happen, but the possibility alone does point to an ethical and legal issue, says Fenucci: “If you release larger space rocks through activities in space that do hit the Earth, then you are in principle responsible.”

This could happen if a catastrophic incoming space boulder is actually billiarded away, but possibly also in the event of explosions to extract raw materials from space rocks, something that a number of companies are planning.

“It’s great that we now know we can deflect an asteroid, and if a few rocks crash into Mars it’s really not a catastrophic ethical problem,” said philosopher of science and religion Mary-Jane Rubenstein of Wesleyan University in Connecticut. USA She wrote the book Astrotopia (2023), in which she warns of the ‘disastrous’ consequences of the current rapid commercialization of space travel.

After all, technology companies have a knack for creating facts, she argues, faster than legislation can keep up, and in this case with potentially disastrous consequences. “And after that it is very difficult to reverse the course of events. I’m not afraid that NASA is going crazy and wants to deflect all the asteroids, but this is an indication of the growing need to come up with legislation for things like space mining.”




SCIENCE