On December 27th, 2024, a hockey-puck-shaped asteroid made a close flyby of the Earth, sending major alerts to the planet's asteroid tracking systems to look out for future impacts.

Meet the now-famous near-Earth asteroid 2024 YR4!

Between the orbits of Mars and Jupiter lies a stretch of space rocks known as the main asteroid belt. Once in a while, Jupiter's gravitational pull kicks these oddly shaped rocks toward the inner Solar System. As these asteroids pass by the Earth on their way toward the Sun, there is always the risk of them hitting the Earth or the Moon.

In 2024, YR4 waved hello to the Earth from approximately 2.5 million kilometres away—almost seven times the distance between the Earth and the Moon. By looking at its path through space, astronomers think that  2024 YR4 must have originated from the main asteroid belt.

Astronomers constantly monitor objects in space that might approach the Earth. While further observations of the 2024 YR4's path have shown that the asteroid will not collide with the Earth, scientists think there is still a chance it could hit the Moon.

A team of astronomers began to take a closer look at 2024 YR4 using the Gemini South telescope in Chile to understand its origins and peculiarities. The team found that 2024 YR4 is an S-type asteroid with a similar composition to that of rocks found on Earth. The asteroid is about 30-65 meters wide – almost the size of a house. The team also found that the asteroid spins rapidly, taking only about 20 minutes to complete one rotation. 

Understanding the origins and characteristics of near-Earth asteroids is essential to estimating the risk of such objects in space hitting our planet and other astronomical bodies in orbit. With powerful telescopes like the Gemini, our planet remains protected from potential impacts.

Image: The composite image of asteroid 2024 YR4 captured with the Gemini South telescope in Chile. Credits: International Gemini Observatory/NOIRLab/NSF/AURA/M. Zamani