The asteroid’s upper size estimate is only slightly smaller than the tallest structure in the world.
According to NASA, a recently discovered, “possibly hazardous” asteroid that is almost the size of the tallest skyscraper in the world will pass by Earth shortly before Halloween.
The diameter of the asteroid, designated 2022 RM4, is believed to be between 1,083 and 2,428 feet (330 and 740 metres), which is barely below the height of Dubai’s Burj Khalifa, the world’s tallest structure at 2,716 ft (828 m), the asteroid’s diameter. According to NASA, it will fly by our globe at around 68 times the speed of sound, or about 52,500 mph (84,500 km/h) (opens in new tab).
On November 1, the asteroid will be around 1.43 million miles (2.3 million kilometres) from Earth at its closest approach, which is roughly six times the typical distance between Earth and the moon. This is a relatively slim margin by cosmic standards.
The term “near-Earth object” is used by NASA to designate any space object that comes within 120 million miles (193 million kilometres) of Earth, and “potentially hazardous” to designate any large body that comes within 4.65 million miles (7.5 million kilometres) of our planet. Once identified as potential threats, these objects are closely monitored by astronomers, who use radar to look for any signs of any deviation from their predicted trajectories that could put them on a devastating collision course with Earth.
About 28,000 asteroids are tracked by NASA, and their positions and orbits are determined using the Asteroid Terrestrial-impact Last Alert System (ATLAS), a system of four telescopes that can survey the whole night sky in a single pass once every 24 hours.
ATLAS has discovered more than 700 near-Earth asteroids and 66 comets since it went online in 2017. 2019 MO and 2018 LA, two of the asteroids discovered by ATLAS, did in fact strike Earth; the former exploded off the coast of Puerto Rico, and the latter crashed-landed close to the boundary of Botswana and South Africa. Fortunately, those asteroid fragments were small and uninjured.
All of the near-Earth objects’ projected trajectories to the end of the century have been calculated by NASA. According to NASA, there is currently no known threat to Earth from an end-of-the-world asteroid collision for at least the next 100 years (opens in new tab).
However, this does not imply that astronomers believe they should give up searching. There have been many catastrophic asteroid strikes in recent history to justify the continuous vigilance, even though the majority of near-Earth objects may not be civilization-ending, like the planet-busting comet in the 2021 comedic disaster film “Don’t Look Up.”
For instance, a meteor the size of a bowling ball burst over Vermont in March 2021 with the equivalent force of 440 pounds (200 kilogrammes) of TNT. A meteor that erupted in 2013 above the city of Chelyabinsk in central Russia produced a blast roughly equivalent to 400 to 500 kilotons of TNT, or 26 to 33 times the energy released by the Hiroshima bomb (opens in new tab). Fireballs from the 2013 explosion poured down over the city and its surroundings, shattering structures, breaking windows, and injuring over 1,500 people.
Space agencies from all over the world are already developing potential strategies to divert an asteroid if astronomers were to ever detect one heading in our direction. The non-hazardous asteroid Dimorphos was rammed off course on September 26 by the Double Asteroid Redirection Test (DART) spacecraft, changing the asteroid’s orbit by 32 minutes. This was the first test of the Earth’s planetary defence system.
Asteroid-redirect mission may already be in the early planning phases, according to China (opens in new tab). The country plans to launch 23 Long March 5 rockets toward the asteroid Bennu in an effort to divert it from a possibly disastrous collision with Earth between the years 2175 and 2199. Bennu is predicted to swing within 4.6 million miles (7.4 million km) of Earth’s orbit.