UN monitors asteroid with a tiny chance of hitting Earth

UN planetary defense organizations are closely watching an asteroid that has a very small chance of hitting Earth.

The European Space Agency (ESA) stated that there is almost a 99% chance it will safely pass by Earth on December 22, 2032, but a possible impact "cannot yet be entirely ruled out."

The chance of the asteroid, named 2024 YR4, hitting Earth on December 22, 2032, is currently estimated at 1.3%.

Dr. Robert Massey of the Royal Astronomical Society says he is "not panicking or losing sleep over it."

"There is no need for alarm," he said. "These kinds of events historically tend to become less concerning as calculations are refined."

We need to stay alert and provide astronomers with the resources they need to track these threats so we can act as soon as possible.

YR4 was detected on December 27, 2024. Astronomers calculated it to be between 40m and 90m across. If it were to hit Earth, it would have the power of a nuclear bomb and cause severe damage if it impacted a populated area.

However, it is much more likely that YR4 would fall into the ocean or a remote part of the planet. It is too far from Earth, and there are too many uncertainties at this stage to determine where a potential impact could occur in the unlikely event of a collision.

Since early January, astronomers have been using telescopes to calculate the asteroid's size and trajectory more precisely. YR4 is now rated at level 3 out of 10 on the Torino Impact Hazard Scale: "a close encounter that warrants attention from astronomers and the public." A collision is only certain when it reaches 8, 9, or 10, with the numbers rising in line with the damage likely caused. When asteroids are initially calculated to have a small probability of hitting the Earth, that impact probability usually drops to zero after additional observations.

This happened in 2004 when an asteroid called Apophis was calculated to have a 2.7% chance of striking Earth in 2029; further observations ruled out an impact.

Any object that may be more than 50m wide and has a greater than 1% chance of hitting the Earth triggers a set of precautionary measures. These are to ensure that the threat, however tiny, is closely monitored and, if necessary, steps are taken to nullify it.

The first stage is to activate two UN-endorsed asteroid reaction groups: the International Asteroid Warning Network (IAWN), chaired by NASA, and the Space Mission Planning Advisory Group (SMPAG), chaired by the European Space Agency.

The SMPAG is having a series of meetings this week to determine its next steps. It has already concluded that it is too early to take immediate action but said that it would "monitor the evolution of impact threat and possible knowledge about the size closely."