NASA makes emergency decision over 'city-killer' asteroid heading for Earth

Table of Contents

As the likelihood of it colliding with Earth continues to rise.

Astronomers are keeping a close eye on asteroid 2024 YR4, which currently has a 2.3% chance of colliding with the Earth in 2032.

The object has leapt to the number one spot on NASA's watch list after it was first spotted in December 2024.

reports.

Based on current calculations, a strike from YR4 would be roughly equivalent to the Tunguska asteroid, which flattened 2,150 square kilometres of Siberian forest in 1908.

But early estimates of the asteroid's size might be wrong.

Scientists currently forecast the dimensions of asteroids by using high-powered telescopes to gauge the light reflected from its surface.

In general, the bigger an asteroid is, the brighter it'll appear, but this isn't always the case, and as all earth-based telescopes have to deal with the earth's atmosphere, which bends and distorts light passing through it, the exact size of celestial bodies can be unclear.

To overcome this, astronomers are planning to use the James Webb Telescope – the biggest and most advanced telescope ever created, which was launched into space in 2021 and is currently 1.5 million kilometres out from Earth.

Using its suite of infrared sensors, the JWST will also examine the heat being emitted by the asteroid, which will provide a much more precise assessment of its size.

This information will enable Earth's planetary defence agencies to decide if action is required to deflect the asteroid.

An ESA spokesperson said: "Astronomers around the world are using powerful telescopes to measure the asteroid's orbit as accurately as possible. But knowing its orbit will only tell us the asteroid could hit Earth, not how big the impact could be."

‘It’s crucial we upgrade our size assessment for 2024 YR4: the danger posed by a 40 metre asteroid is significantly different from that of a 90 metre asteroid,” ESA stated.’

Even at its estimated size, experts reckon YR4 could detonate with an energy of 15 megatons of TNT if it were to hit Earth, resulting in an explosion 100 times more potent than the atomic bomb dropped on Hiroshima during World War II.

The first round of James Webb observations will kick off in March when the asteroid is at its brightest point. The telescope will then keep an eye on it as it moves further away from the sun, which will be the last opportunity to observe it until it pops back into view in 2028.

These measurements will in turn be 'used by ESA, NASA, and other organisations to more confidently assess the hazard and determine any necessary response,' the ESA said.

.

.