2024 YR4: An Asteroid Under Surveillance

On December 27, 2024, astronomers discovered a new asteroid that immediately caught their attention. Named 2024 YR4, this celestial object belongs to the category of Near-Earth Objects (NEOs)—asteroids whose orbits intersect with Earth’s. What makes it unique? It has a very low probability of impacting our planet in 2032, prompting space agencies like NASA and ESA to closely monitor its trajectory.

The announcement of 2024 YR4’s discovery quickly sparked interest among the public and scientists, as early analyses suggested that it could potentially collide with Earth in a few years. However, experts caution against drawing premature conclusions, emphasizing the need to collect more data to refine its orbital parameters and accurately assess the potential risks it poses.

Discovery and Characteristics of 2024 YR4

The asteroid 2024 YR4 was detected on December 27, 2024, by the Asteroid Terrestrial-impact Last Alert System (ATLAS), a NASA-funded monitoring network based in Chile. This program is designed to detect Near-Earth Objects (NEOs) that could pose a potential threat.

After multiple observations, astronomers confirmed its orbit and key characteristics.

An Uncertain Size

Initial analyses estimate that 2024 YR4 measures between 40 and 90 meters in diameter, according to ESA. This margin of uncertainty is due to the limitations of ground-based telescopes, which do not allow for an immediate precise measurement of an asteroid’s size. It is likely that it exceeds 50 meters in diameter. However, even an object of this size could cause significant damage in the event of an impact.

For comparison, the asteroid that exploded over Chelyabinsk in 2013 was about 20 meters in diameter and caused injuries to over 1,500 people, primarily due to the shockwave from its atmospheric explosion.

An Orbit That Crosses Earth’s Path

2024 YR4 belongs to the Apollo family of asteroids, a group of Near-Earth Objects (NEOs) whose orbits cross Earth’s. This means that it regularly approaches our planet, increasing the chances of close encounters.

Based on initial observations, the asteroid follows an elliptical trajectory around the Sun, periodically bringing it close to Earth.

• Orbital period: Approximately 1.2 years to complete one orbit around the Sun.
• Relative speed: Estimated at several tens of thousands of kilometers per hour, typical for objects of this kind.

Intensive Monitoring to Refine Its Parameters

The exact trajectory of 2024 YR4 is still under analysis. Each new observation helps refine its orbit, which is crucial for accurately assessing the risk of impact in the coming years. Astronomers use complex mathematical models to predict its future movement, but uncertainties always remain in the first few weeks following an asteroid’s discovery.

Here is a sequence of observations of the near-Earth asteroid 2024 YR4, carried out with the Very Large Telescope (VLT) of the ESO in early January. The images have been aligned so that the asteroid remains fixed at the center of the frame.

A Risk of Impact in 2032?

One of the factors that immediately caught astronomers’ attention after the discovery of 2024 YR4 is the possibility that it could collide with Earth by 2032. According to preliminary orbital analyses, the key date to watch is December 22, 2032, when the asteroid is expected to pass relatively close to our planet.

A Probability to Be Put into Perspective

According to preliminary calculations by NASA and ESA, as of January 29, the probability of an impact is currently estimated at 1.2%, or approximately 1 in 83. Generally, these impact probabilities tend to decrease over time as more precise data is collected.

The Torino Scale: A Level 3 Out of 10

To assess the potential threat of an asteroid, scientists use the Torino Scale, which ranks celestial objects on a scale from 0 to 10 based on their impact probability and potential damage. 2024 YR4 is currently classified at Level 3, meaning that it warrants attention from astronomers, but no immediate alert is necessary.

Comparisons with Other Asteroids

Although 2024 YR4 is considered an object requiring increased attention, it is not as concerning as some previously discovered asteroids. For example:

• Apophis (99942): This asteroid was once classified at Level 4 on the Torino Scale, before more precise observations confirmed it posed no danger.
• Bennu (101955): This asteroid has a very low probability of impacting Earth in the late 22nd century, but NASA has planned monitoring and deflection strategies if necessary.

Thus, even though 2024 YR4 remains under close surveillance, there is a high probability that its threat level will decrease in the coming years, thanks to refined trajectory calculations.

Ongoing International Monitoring

Since its discovery, 2024 YR4 has been closely monitored by multiple international space agencies, including NASA, ESA, and other organizations specializing in Near-Earth Object (NEO) observation. These institutions use ground-based telescopes and specialized satellites to track its trajectory and assess its potential risk.

For now, no immediate action is required, but 2024 YR4 will remain under constant observation. Astronomers will continue refining their calculations until the threat is completely ruled out—or, if necessary, until intervention becomes required.

Source

Find an article published by ESA on January 29, 2025, here, and stay updated on the latest observations of this asteroid here. This article is a translation from the Agences-Spatiales.fr