Newly discovered asteroid to zoom past Earth

An asteroid the size of one to two school buses will fly past Earth on Monday, coming as close as 91,593 kilometers (56,913 miles), according to the European Space Agency, the equivalent of about a quarter of the distance between Earth and the Moon.

Astronomers at the Mount Lemmon Survey in Tucson, Arizona, discovered the asteroid on May 10 and named it 2026JH2. The object belongs to a class of asteroids called Apollo, which orbit the sun on trajectories that intersect Earth’s orbit around the sun.

At its closest pass, 2026JH2 will be about 24 percent of the average distance between Earth and the Moon, and about two and a half times the distance at which hundreds of geosynchronous satellites orbit, providing services such as telecommunications and weather forecasting. The close pass is expected to occur Monday just before 6 p.m. ET, according to NASA’s JPL Small-Body database.

Despite its proximity, the space rock poses no danger, according to Richard Binzel, professor of planetary sciences at the Massachusetts Institute of Technology and inventor of the Turin scale, a tool for categorizing potential collisions of space objects with Earth.

“2026JH2 will pass safely near Earth,” he said in an email. “It’s actually a pretty normal phenomenon: objects the size of a car pass between the Earth and the Moon every week. The size of a school bus, they pass through our neighborhood several times a year. We are only recently developing surveys sensitive enough to see them,” he added, noting that before these surveys, objects of this type simply slipped by completely unnoticed.

The asteroid came from the asteroid belt, an area between Mars and Jupiter, Binzel explained. “Occasional collisions in the asteroid belt, as well as gravitational tugs from Jupiter, can send small asteroids close to Earth. This fact has been known for many decades, and several thousand asteroids that can pass near Earth are already known.”

Although astronomers have directly observed the object hurtling toward Earth, its exact size is unknown. The uncertainty is because when an optical telescope sees a new object, the only information it collects is the brightness of the object in visible light. There is no way to know how much light the object absorbs or reflects, according to Patrick Michel, an astrophysicist and research director at the National Center for Scientific Research in France.

“So, at equal brightness, an object can be larger and darker, or smaller and more reflective,” he explained in an email. “To know the size, we would need infrared observations, because infrared brightness is directly proportional to size. But such observations are more difficult to make from Earth and are not useful for discovering new objects.”

Based on assumptions about the amount of reflected light, 2026JH2 is currently estimated to be between 15 and 30 meters (50 and 100 feet) in diameter. At the smaller end of that range, Michel said, its size would be similar to that of a bolide, or fireball, that exploded in the atmosphere above the city of Chelyabinsk, Russia, in 2013, shattering windows and injuring 1,000 people. At the highest end of the range, it would be closer in size to an object that exploded near the Podkamennaya Tunguska River in Siberia in 1908, pulverizing large areas of forest. However, unlike those two objects, 2026JH2 won’t even enter the atmosphere, so there is no risk of it exploding.

Although the distance the asteroid will pass seems very close, it is still “far enough away that there is absolutely no reason to worry,” Michel said. But he noted that it is difficult to predict the future trajectory of 2026JH2 and that we cannot rule out that it could eventually end up on a collision course with Earth. “The good news is that so far, no asteroid that we know of poses a risk for the duration of our predictions, which is about a century on average,” he added.

An object at least 10 times larger than 2026JH2, named Apophis, will pass much closer to Earth, at an expected distance of 32,000 kilometers (20,000 miles), on April 13, 2029. “However, we are not at all worried, and on the contrary very excited,” Michel said. “Such a close approach to such a large object only happens once every few thousand years and its light will even be visible to the naked eye in the night sky in Europe, Africa and part of the Middle East.”

On the other hand, during its closest approach, 2026JH2 will only be detectable with small telescopes at dark sites, but it will remain 100 times too faint to be seen by the human eye, according to Jean-Luc Margot, professor of Earth, planetary and space sciences at the University of California, Los Angeles.

Part of the reason we don’t have more detailed information about the asteroid, he added in an email, is that our planetary radar capabilities are currently degraded. “The Arecibo telescope collapsed in 2020 and NASA’s Goldstone antenna is down for major repairs for an extended period. Without radar data, we are less able to assess impact risk and we are more vulnerable to impact risk.”

A partial live stream of the close pass will be provided by the Virtual Telescope Project using telescopes in Italy, starting at 3:45 p.m. ET, and until the object is no longer visible from that location.

So far, astronomers have observed only about 1 percent of near-Earth asteroids in the same size range as 2026JH2, Margot said, and so “it is not surprising that this object was discovered just days before its closest approach to Earth, when it became bright enough to be detected by asteroid detection studies.”

He added that it is concerning that we do not have complete knowledge of the near-Earth object population, but noted that space agencies are now actively funding discovery surveys to improve our inventory of potentially hazardous asteroids.

Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with information on fascinating discoveries, scientific advances and much more.