Why the UN waiting for May to act

NASA has raised to 3.1% the probability that the Asteroid 2024 YR4 falls on our planet. The Coordination Center of objects close to the Earth of ESA also has adjusted its upward calculationsestimating a 2.8% impact probability for December 22, 2032.

Let us not lose sight of the fact that bets are still in our favor. 1 Between 32 possibilities means that there is a 96.9% probability that the asteroid will pass by. But as astronomers have incorporated new data and observations to calculate their trajectory, The impact options have been increasing. Why does this happen? We have asked Juan Luis Cano, planetary defense coordinator of ESA

The busiest man of that

Aeronautical Training Engineer, Juan Luis Cano He specialized in orbital mechanics and celestial mechanics, which are the basis for calculating the movement of objects in the outer space. 20 years ago it was part of the Don Quixote projecta mission of the European Space Agency to divert an asteroid with a kinetic impactor.

Led by the Spanish company Deimos, Don Quijote did not prosper, but was the precursor of the NASA dart probewhich successfully diverted the Dimorfo asteroid, and the ESAthen launched to analyze the impact.

As coordinator of the Information Service of the ESE Planetary Defense OfficeCano is especially busy these days. For the first time They have activated planetary defense action protocols established in 2018, which implies coordinating as many observatories as possible to follow the asteroid carefully.

“These action protocols were established after the UN promoted the creation of the International Asteroid Alert Network and the Advisory Group for Space Missions Planning,” says Cano. “It is the first time that they are officially invoked, although this asteroid is the most relevant of the last 20 years, after Apofis at the end of 2004.”

At the moment, the Space Missions Planning Advisory Group (SMPAG) has decided to wait for May to assess, based on new more definitive observations, if the asteroid continues to assume a real danger.

Why the impact probability has risen

As they obtain more data and observations from 2024 YR4, astronomers reduce the uncertainty of their trajectory, but their calculations are still focused on the impact probability with earththat does not change size.

If the Earth remains within the area of ​​uncertainty, the probability of impact rises because uncertainty becomes smaller, but our planet remains in the middle. “It’s as if you’re going around in a championship,” explains Juan Luis Cano. “You don’t know if you are going to win, but after 32 teams to 16, your chances increase.”

It can also happen that the probability distribution is “sliding” and the earth moves away from the central part of the graph, which happened when The estimate dropped from 2.3 to 2.1% A few days ago before going back up.

European scientists They use the Turin scale to categorize the risk posed by asteroids and comets near Earth. With a qualification of 3 out of 10, 2024 YR4 exceeds the 1% probability threshold of causing a destruction located on Earth. However, the new observations are most likely to reduce that estimate to zero.

It was what happened with the asteroid apofis. Apofis reached a level 4 on the Turin scale, the highest ever registered. But astronomers extended their observation arc and ruled out the impact after a few days.

Now the NASA OSIRIS-APEX He goes to him to study it when he passes only 38,000 km from the earth. It is the same ship as collected the samples of asteroid Bennuwhich demonstrates the importance that missions are acquiring these small bodies close to Earth.

Cano bets that the Earth will leave the probability distribution when we have webb data and other observatories in the coming weeks.

What is the protocol to follow in both cases

There are things that astronomers know for sure about 2024 YR4, such as the plane in which it moves and The Earth Strip in which it could fallThe case is: a “corridor” that extends through the Eastern Pacific Ocean, northern South America, the Atlantic Ocean, Africa, the Arabic Sea and the south of Asia.

There are others that are complicated. The asteroid was discovered in its approach to the Earth and Now he is moving awayso, every day that passes, it becomes more dim and costs more to see it. For April, not even the great Canary Islands telescope (10 meters in diameter) can detect it.

Nor is there a precise measurement of its size because its albedo is unknown, the amount of light that your body reflects. It could be an object of 40 meters very reflective or an object of 90 meters very dark.

To get out of doubt, astronomers have reserved hours of emergency use of the powerful James Webb Space Telescope. The Webb will be able to observe the asteroid until May and You can obtain a more accurate measurement of your size and temperature

Discerning if it is at the lower or upper end of the estimated size range is crucial to evaluate the consequences of its unlikely but possible impact. While it is too small to end human civilization, the asteroid could destroy an important city, especially if it explodes in the air.

As for its destructive capacity: “We cannot speak of a single value, but of a range that goes about 5 to 50 megatones, depending on whether the object measures 40 or 100 meters,” says Juan Luis Cano. “The greater the diameter, the more the volume and potential energy of the impact is multiplied. So there is no exact figure until we know its diameter better.”

And what would we finally go to Earth? “If the object is less than 50 meters, it is considered preferable Evacuate the impact zone; If it is greater, a deviation mission would be assessed, “Cano explains.” Even so, we think that, with 90% probability, in May the impact will be definitively ruled out. “

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