In 2032, an asteroid will strike Earth, with an explosion comparable to that of an atomic bomb.

In December 2032, an asteroid may collide with Earth. There is a possibility that we could face a second Tunguska event. Unfortunately, this is not mere hype or an exaggeration. The celestial body known as 2024 YR4 is leading the list of cosmic dangers in all assessments. Where did this threat come from, and what will happen?

DANGEROUS STAR

On December 27 of last year, a telescope in Chile detected a star that was moving very quickly across the sky. It became clear that an asteroid had passed by us. This is not an extraordinary occurrence; telescopes are now highly sensitive and discover many such objects. At the time of its discovery, the celestial body was already moving away, having approached within 830,000 kilometers (much farther than the Moon). The decision was made to gather observations and calculate its orbit, just in case it returns.

The orbit raised immediate concerns. It turned out that the asteroid would indeed return, and moreover, there is a non-zero probability of it colliding with Earth on December 24, 2032. Astronomers are now trying to understand exactly what that probability is, while also gathering new data about this dangerous object.

RED ALERT SIGNAL

Scientists have levels, or scales, of asteroid danger: the Torino and Palermo scales (see Reference). The asteroid was immediately assigned a score of 1 on the Torino scale (indicating a collision probability of 1 in 10), which is the highest score among all celestial bodies being monitored by astronomers.

One in ten may seem low, but it is not zero! More precise calculations consistently indicated a non-zero probability as well. The most likely scenario is that the celestial body will pass within two million kilometers of Earth. However, there is still a risk of a collision. Given the vast range in predictions, new observations were required.

Despite the high cost of observational time on large telescopes, and the fact that the asteroid had moved away and become barely visible, powerful and expensive telescopes were quickly mobilized to accumulate observations.

Then something strange happened.

INCREASINGLY DANGEROUS

Currently, 260 observations have been accumulated. This is a significant number, considering that an orbit can generally be calculated with just three observations.

What the astronomers are finding is concerning.

- Typically, as we continue to observe a potentially hazardous object and increase the accuracy of its orbit, the probability of a collision decreases, and in most cases, it disappears altogether. But not in this case. Now, asteroid 2024 YR4 has become the most dangerous object according to both the Palermo and Torino scales, being rated at 3 points (potential local damage) out of 10 (imminent planetary catastrophe), whereas just two weeks ago it was rated at only 1 point, - writes Russian astronomer Leonid Elenin in his Telegram channel.

Thus, as we learn more about this celestial body, it appears increasingly hazardous. This is at the very least alarming.

EIGHT MEGATONS OF TNT

Understanding the size of the asteroid and what will happen upon its impact is challenging, but possible. We can observe its brightness through telescopes, and we know the distance to it. What remains is to estimate its reflective capacity (there are methods for this, though they are not always reliable).

So far, the consensus is that the asteroid has a diameter of 55 meters, but the range is still large, extending up to over 200 meters. Given that collision speeds are cosmic, even a slight increase in diameter significantly raises the explosion's force. A 50-meter body created the famous crater in Arizona (with a diameter of nearly 1.5 km, and indigenous people reportedly remember something falling from the sky). A little larger, with a diameter of 60-70 meters, would already mirror the scale of the Tunguska event, notes Leonid Elenin. And what about 200 meters? It's better not to think about that.

Although the collision speed will not be the highest (around 17 kilometers per second; some meteors reach 60 kilometers per second), the explosion's power is estimated at eight megatons. "That's an atomic bomb," clarified Leonid Elenin during a broadcast on "Radio Komsomolskaya Pravda."

Understanding the size of the asteroid and what will happen upon its impact is challenging, but possible. We can observe its brightness through telescopes, and we know the distance to it.

Photo: Shutterstock.

It is (almost) certain that it will not strike Russia. According to calculations, the possible impact zone extends from southern India through the southern Arabian Peninsula and equatorial Africa to South America. As you can imagine, it could also fall into the ocean, whether in the Indian or Atlantic.

WHAT HAS IT SO SPOOKED

The probability of a collision (setting aside scales and scores) is estimated at about one percent. So why are scientists so alarmed? Everything is relative, and in fact, this is a significant number, says candidate of physical and mathematical sciences, senior researcher at the Institute of Applied Astronomy of the Russian Academy of Sciences Nikolai Zheleznov.

Currently, the world record holder for danger is asteroid Apophis, which was once thought to be on a collision course (but it has since been determined that it is not). At the peak of concern, it had a score of 4 on the Torino scale, but its collision probability was only assessed at 2.7%.

- The main thing is that it’s not zero, - says Nikolai Zheleznov.

Of course, there are asteroids with a 100% chance of collision. These are small bodies that have recently been detected as they approach Earth. One, for instance, recently fell in Yakutia. But how many points would it score on the Torino scale? Zero, because such small rocks are safe and almost completely burn up in the atmosphere. In contrast, the Chelyabinsk meteor would score 8 (a local scale event). The Tunguska event might receive a 9 (regional scale). The asteroid that wiped out the dinosaurs would score a 10 (planetary scale).

This means scores are also assigned based on the severity of the consequences. In this context, three points for the new asteroid is not insignificant. And the high score is mainly due to its size.

"I'M SURE IT WILL BE OKAY"

But why do astronomers sometimes say that the asteroid is dangerous (as was the case with Apophis), then retract their statements? Is it that they cannot determine its orbit?

The issue is that, during observations and subsequent calculations, there are inevitably errors, explains Nikolai Zheleznov.

- When we obtain the orbit, we are essentially projecting events forward. We define not a specific point where the asteroid will be, but a certain area of probability. Does Earth fall within that area? Suppose it does. Then we accumulate observations, refine the orbit, and see that it does not. This is usually how it goes, - the astronomer explains.

There are few, if any, undiscovered asteroids of kilometer size left. We know them all; none pose a threat to us. The PAN-STARRS project aims to find all asteroids larger than 140 meters. It is believed that a body of 140 meters in size, even if it is loose, will definitely reach Earth, explains Nikolai Zheleznov.

If asteroid 2024 YR4 were to impact the Earth, it would create a crater; if it fell into the sea, it would generate a tsunami. It is unclear which would be worse.

- Still, I do not believe it will fall. I am confident that as data accumulates, the assessment of danger will decrease, - asserts the astronomer.

OUR REFERENCE

How asteroid danger is assessed

The most straightforward is the Torino scale, developed by Professor Richard Binzel. It includes both the probability of collision and the potential harm from it. A score of 0 means it will either pass by or burn up in the atmosphere. A score of 10 means it will definitely collide and cause significant damage. The famous Apophis had a score of 4 at the peak of concerns, but now it is zero. The Palermo scale is more precise. It takes into account collision energy and other parameters.