Imagine a space rock hitting the moon. It causes fragments of moon rock to fly into dark voids in space. What would the wonder look like?
Scientists have created a sensation by using the Chilean Rio Hertado’s Atlas telescope to discover the asteroid in December 2024 as a new entrant in the asteroid database. It has kept planetary defense scientists on its toes since its discovery, as it could one day collide with Earth.
Alarm, alarm is closed
YR4 is a near-Earth asteroid, an object orbiting the sun, whose approach to the stars is within 1.3 times the positive distance of the Earth. If the orbits cross the Earth’s orbit, then the asteroids of the category are classified as potentially dangerous objects and their width exceeds 140 m.
Astronomers first estimate the size of the asteroid YR4 using a wide ground telescope that operates within the visible range. Since then, infrared observations from James Webb’s space telescope reveal clear pictures of the size of an asteroid. YR4 is now estimated to be 65 m in width, about the size of a 10-story building. For comparison, the space rock that wiped out dinosaurs 66 million years ago was 10 kilometers wide.
Even if the YR4 does not meet the 140-meter threshold, its non-tiny size and its trajectory are enough to make NASA sound the highest (historically) asteroid impact alert ever in mid-February. The agency announced at the time that YR4 had a 3.1% chance of hitting the planet in 2032. In a subsequent update, with more data and careful analysis followed, NASA revoked the update, saying its chances of hitting the planet are actually negligible and could hit another body.
Probability of impact
On April 2, NASA announced that the YR4 has a 3.8% chance of chance on December 22, 2032, about seven and a half years. But there is still a 96.2% chance to miss it.
Observations built by astronomers have been searching for new asteroids in the sky and are also focusing on known potential dangers. Scientists use the observational data they collect to build computer models to find out the orbits of these objects. (When they enter the solar system, the sun’s gravity places them in the surrounding orbits.) The researchers then asked these models to check whether future orbits intersect with the Earth.
“It’s now an automatic search for asteroids and other near-Earth objects,” said Jayant Murthy, an emeritus professor at the Institute of Astrophysics in Bangalore. “That is, they took continuous pictures of the sky and used algorithms to find anything moving.”
“In other words, the cyclone is uncertain. In other words, several similar orbits can fit the observations. She is the author of the 2017 book Asteroid Hunter.”
Both Nugent and Murthy are named after them.
Seeing it coming
“The problem is that many of these objects are weak, without observational history, so they try to get tracks from very few perspectives. So there is some uncertainty about the path to the track, which is… reflected in the numbers,” Morsi said.
As scientists acquire more data, they will refine estimates of asteroid size and paths and update their models. This leads to more accurate predictions of the future location of the asteroid.
this NASA Sentinel The website lists all the latest impact probabilities of attention asteroids. It uses the Torino scale to evaluate the harm of each rock to the earth. A rating of 0 indicates no threat and 10 indicates global disaster. YR4 has three ratings before astronomers discovered that it is mostly harmless.
Even if YR4 should hit the moon, the moon’s orbit will not change – but it will emit 500 to 2,000 meters of impact craters. The impact zone will tremble with 340 explosions that are stronger than the Hiroshima bomb.
Spacecraft orbiting the moon, such as the Chandrayaan-2 orbit in India, will be able to see its arrival.
Preventable disasters
However, whether astronomers are visible on Earth will divide. Some scientists say that helpless eyes cannot see it because of the brightness of the moon. Other differences: For example, Gareth Collins, a professor of planetary science at Imperial College London, told New Scientist In February, “even during the day, the impact flash of evaporating rocks can be seen from the earth.”
“It would be very exciting to see it!” Nugent said.
“You will only get a bright flash on the moon. If it’s near, there will be [many] The telescope observes it because it will tell you about the moon’s thunder fruit and its components. “Morsi said.
YR4 will pass Earth again in 2028. Scientists will be able to get more data after the four-year gap, refine their models, and better understand whether an asteroid may hit the moon.
Finally, even if YR4 changes from “threatening” to “no threat”, the Earth is still bombarded by rocks in space like the 2013 Chelyabinsk Meteor. “The problem with larger asteroids is that the Earth is very fragile, and asteroids will dump a lot of dust in the atmosphere, which will have a huge impact on the climate years or decades before life can recover,” Morsi said.
“We may have had catastrophic collisions in the last century and we knew there would always be big catastrophes.”
But there is hope. As Nugent said, “Asteroids are the only preventable natural disaster.”
Unnati Ashar is a freelance science journalist with a master’s degree in space physics.
publishing – May 12, 2025 at 05:30 AM IST
