Astronomers recently discovered an Olympic-sized asteroid that could smash into Earth in 2046 on Valentine’s Day, but the odds of a collision narrowed further on Tuesday.
Called “2023 DW”, the celestial object 50 meters in diameter was spotted for the first time on February 26 by a small Chilean observatory.
The American (NASA) and European (ESA) space agencies quickly ranked it at the top of the list of potentially dangerous objects, its theoretical trajectory passing close enough to Earth to pose a threat of collision.
If it were to intervene, the calculations anticipate it for February 14, 2046, Valentine’s Day. Newspapers made their headlines, and advised lovers to cancel their plans.
At the end of February, the asteroid had a chance in 847 of crashing into Earth… A probability raised to one in 432 on Sunday, according to the list of risks drawn up by the ESA. NASA estimates pointed in the same direction.
But overnight, the probability fell to one chance in 1,584 on Tuesday, Richard Moissl, head of ESA’s planetary defense office, told AFP.
A probability that will decrease “with each observation, until reaching zero in a few days at the latest”, he added.
His counterpart at NASA, Lindley Johnson, agreed, saying that “at this point, no one should be worried”. According to him, it is common for collision forecasts to rise briefly in the days following the discovery of a new asteroid, before falling.
The Earth is initially in a “zone of uncertainty” on the trajectory of the asteroid, which justifies the temporary increase in risk. Before new observations exclude the Earth from this region.
What if he hits us?
But what if 2023 DW crashed into us anyway? The extent of the damage would depend on the composition of the celestial body, experts point out.
If it’s a pile of debris, the scenario could resemble the “Tunguska event” in Siberia in 1908, a large explosion attributed to the fall of an asteroid, recalls Davide Farnocchia, scientist at the Jet Propulsion Laboratory (JPL ) from NASA.
The celestial object, of the same ilk as 2023 DW, is said to have exploded in the atmosphere above a sparsely populated area, flattening trees over an area of around 2000 km2.
The asteroid could also be a “solid piece of iron”, like the one that created the massive Barringer Crater in Arizona 50,000 years ago, according to Richard Moissl.
In both cases, given its size, 2023 DW would only cause “localized damage”, without major impact on the rest of the planet, assures the expert.
In orbit around the Sun, the object passed closest to the Earth on February 18, a week before its discovery. It was then at a distance of about 9 million kilometers.
If it were to hit us in 2046, its speed would be 15 km per second, or 54,000 km/h, according to estimates.
There would be around a 70% chance of it landing in the Pacific Ocean, but the potential strike zone would also include the United States, Australia or Southeast Asia.
Experts point out, however, that we are no longer defenseless against such a threat. Last year, the ship DART of NASA deliberately crashed into the asteroid Dimorphos, about 11 million kilometers from Earth, and managed to divert its trajectory.
” The mission DART gives us the assurance that such a mission would be crowned with success” against the asteroid DW of 2023, reassures Davide Farnocchia. There is “plenty of time”, 23 years exactly, to prepare for it, concludes Mr. Moissl.