Asteroid 2024 YR4 was discovered just a month ago. It is being monitored because there is a possibility – though very small – of impact with Earth in 2032. What do we know so far about this asteroid, and what would the consequences be if it hit Earth?
What do we know so far?
Asteroid 2024 YR4 was discovered on December 27th, 2024, using the ATLAS telescope in Rio Hurtado, Chile.
According to current calculations of its orbit, this celestial object could approach Earth as close as about 2.000 kilometers on the afternoon of December 22nd, 2032.
What comes next, and how (powerless) are we to prevent the consequences?
Estimates show that asteroid 2024 YR4 is likely larger than 50 meters and has a probability of impact greater than 1% at some point in the next 50 years. This meets all the criteria for activating two internationally recognized asteroid response groups: the International Asteroid Warning Network (IAWN) and the Space Mission Planning Advisory Group (SMPAG).
IAWN
IAWN, chaired by NASA, coordinates activities of international organizations involved in asteroid monitoring and analysis. If necessary, this network will develop a strategy to assist governments in assessing the consequences of a possible impact and planning risk mitigation measures.
The orbit of asteroid 2024 YR4 around the Sun is elongated (eccentric) – it takes four years to complete one orbit. It is currently moving away from Earth in an almost straight line, making it difficult to precisely determine its orbit by tracking its curvature over time.
In the coming months, the asteroid will become increasingly difficult to observe from Earth. It is possible that asteroid 2024 YR4 will disappear from view before the possibility of impact in 2032 can be definitively ruled out.
SMPAG
SMPAG, chaired by the European Space Agency (ESA), is responsible for international information exchange, developing joint research and missions, as well as planning strategies for mitigating threats posed by near-Earth objects, including asteroid 2024 YR4.
The group will hold a regular meeting next week in Vienna to determine the next steps. If the probability of impact remains above the 1% threshold, SMPAG will make recommendations to the United Nations (UN) and may begin assessing possible responses to the threat, including spacecraft missions.
What if it actually hits Earth?
If asteroid 2024 YR4 were to actually hit Earth, the consequences would depend on its composition. If it is a loose pile of rocks and dust, it would explode in the atmosphere at high altitudes, a so-called airburst. Such an event would produce a powerful shockwave and extreme heat affecting the ground, similar to the 1908 explosion over the Tunguska River in Siberia, where more than 2,000 square kilometers of forest were burned and flattened.
If the asteroid is a solid rock or even a metallic object, it could create a crater up to one kilometer in diameter. A similar event occurred about 50.000 years ago when an asteroid struck what is now Arizona, United States (U.S.), forming the famous Barringer Crater. The impact explosion would cause destruction within a radius of about 50 kilometers. Such an event would be as powerful as an extremely strong hydrogen bomb explosion but without radioactive radiation. However, this catastrophic scenario is extremely unlikely.
