Scientists Track "City-Killer" Asteroid's Chances of Hitting Earth

A potentially dangerous asteroid named 2024 YR4 has caught the attention of astronomers. It's estimated to be between 130 and 295 feet wide, which is roughly the size of half an American football field.

While it has a small but non-zero chance of colliding with Earth in 2032, scientists are taking the threat seriously by using the James Webb Space Telescope (JWST) to better understand the asteroid's size, path, and if it will impact Earth.

What We Know About Asteroid 2024 YR4

Asteroid 2024 YR4 was first spotted in December 2024. Since then, observations and calculations have allowed scientists to estimate its orbit and assess the likelihood of it hitting Earth. Initial projections put the chances of a collision at around 1%, but subsequent analysis by NASA's Jet Propulsion Laboratory (JPL) and the European Space Agency (ESA) have slightly increased that probability.

Currently, the asteroid's chance of hitting Earth on December 22, 2032, stands at around 2%. Although seemingly small, any number bigger than 0% warrants some attention and further investigation. The ESA has placed Asteroid 2024 YR4 on its risk list, a catalog of near-Earth objects that require careful tracking.

A "City-Killer" Asteroid

While not large enough to destroy the entire world, Asteroid 2024 YR4 is classified as a "city-killer" asteroid. An impact from an object of this size could cause some heavy damage. The ESA stated that an asteroid of this scale "impacts Earth on average every few thousand years and could cause severe damage to a local region."

If the asteroid were to land in a populated area, it would be truly catastrophic, though the effects would be limited to where exactly it lands. An event like this wouldn't be comparable to the asteroid impact that led to the extinction of the dinosaurs and wouldn't affect the global climate.

Potential Zones at Risk

Should Asteroid 2024 YR4 strike Earth, NASA scientists have identified potential impact zones across the globe. These include areas over the eastern Pacific Ocean, northern South America, the Atlantic Ocean, Africa, the Arabian Sea, and South Asia.

An impact over the ocean could cause a large tsunami, putting coastal communities at risk. A land impact would cause widespread destruction, loss of life, and long-term economic disruption - particularly in a densely populated area.

The James Webb Space Telescope

To better understand the threat posed by Asteroid 2024 YR4, astronomers are turning to the powerful James Webb Space Telescope. The JWST was launched in 2021 and is the most advanced space telescope ever built, equipped with cutting-edge instruments capable of observing the universe in unprecedented detail.

One of the primary goals of using the JWST is to gain a more accurate estimate of the asteroid's size. Current estimates place the object's diameter between 130 to 295 feet. However, these figures are based on observations of the visible light reflected by the asteroid, which can be affected by factors such as its surface composition and reflectivity.

The JWST, on the other hand, can measure the infrared emissions from the asteroid, providing a more direct and reliable estimate of its size. This is because the amount of infrared radiation emitted by an object is directly proportional to its surface area and temperature.

As the ESA noted, "It is very important that we improve our size estimate for 2024 YR4. The hazard represented by a 40 m asteroid is very different from that of a 90 m asteroid."

Observation Schedule and Analysis

The telescope will begin studying the asteroid in March, when it appears brightest, and again in May. After these initial observation windows, the asteroid will become less visible for a period of time.

Following the observations, astronomers will dedicate time to analyzing the data collected by the JWST. This will involve processing the raw data, calibrating the instruments, and developing models to interpret the infrared emissions.

Asteroid 2024 YR4 will reappear in 2028, providing another opportunity for ground-based observations to further refine its orbital parameters.

The Torino Scale

Given the potential threat posed by Asteroid 2024 YR4, it has been assigned a Level 3 rating on the Torino Impact Hazard Scale. This scale ranges from 0 to 10 and is used to categorize the risk associated with near-Earth objects.

A Level 3 rating indicates "a close encounter" that warrants public and scientific attention. While it is still considered a low level of risk, it still requires more monitoring and investigation.

Can We Defend Ourselves?

The ongoing efforts to track and characterize Asteroid 2024 YR4 are part of a planetary defense. This involves detecting, tracking, and characterizing near-Earth objects that could pose a threat to our planet.

In addition to observing and tracking, planetary defense also includes developing strategies for lessening the impact risk of asteroids. These strategies range from deflecting an asteroid's trajectory using kinetic impactors or gravity tractors to disrupting or fragmenting an asteroid using nuclear explosives.

NASA's Double Asteroid Redirection Test (DART) mission, launched in 2021, successfully demonstrated the feasibility of using a kinetic impactor to alter the trajectory of an asteroid. This mission provided valuable data and insights for future planetary defense efforts.

Keeping Our Planet Safe

Asteroid 2024 YR4 presents a small but real risk to Earth in 2032. While the odds of an impact remain low, the potential consequences are significant enough to warrant continued monitoring.

As we continue to explore and understand the universe around us, it is crucial to remain informed and proactive in protecting ourselves from potential hazards. While the future remains uncertain, the efforts being made today will help ensure a safer and more secure tomorrow.