Asteroid Size of 8-Story Building To Fly Closer to Earth Than Moon

An 80-foot asteroid is due to soar past the Earth today, passing around twice as close to our planet as the moon.

The asteroid, named 2023 TM3, is estimated to measure between 36 and 82 feet in diameter, according to NASA's Center for Near-Earth Object Studies (CNEOS) data. An 8-story building is around 80 feet tall, for comparison.

2023 TM3 is forecast to pass the Earth at a distance of 0.00111 astronomical units, or around 100,000 miles. The moon orbits at a distance of 240,000 miles, while the sun is about 93 million miles away.

"Asteroids are debris left over from the early formation of the Solar System," Martin Barstow, a professor of astrophysics and space science at the University of Leicester in the U.K., told Newsweek. "They exist on a wide range of orbits due to gravitational interactions between them and other bodies in the solar system."

Asteroids are mostly found clustering in the asteroid belt, orbiting the sun between Mars and Jupiter. 2023 TM3 is a fairly small asteroid at only 80 feet in diameter, with some of the largest asteroids in the solar system measuring several hundred miles across. The largest, Ceres, has a diameter of about 600 miles.

These objects can occasionally be flung out of their orbits due to interactions with Jupiter's gravity, sending them zipping towards Earth. 2023 TM3 is predicted to pass the Earth at 11.51km per second, or around 35,700 miles per hour.

Some asteroids are classified as "near-Earth objects" or NEOs, which are defined as being closer than 30 million miles away. Around 31,000 objects in our solar system fall into this category.

"Asteroids and comets with a perihelion distance (closest to the Sun) less than 1.3 astronomical units (AU), or approximately 120 million miles/194 million km, are called near-Earth objects—or NEOs," Svetla Ben-Itzhak, an assistant professor of space and international relations at Johns Hopkins University, told Newsweek. "Astronomers consider a near-Earth object a threat if it has an Earth minimum orbit intersection distance of 0.05 AU (around 4.7 million miles or 7.5 million km) or less and is at least 140 meters [460 feet] in diameter. Those are known as potentially hazardous objects (PHOs)."

PHOs also have to have an absolute brightness of 22.0 or less, Barstow explains. Due to its smaller size and lower brightness, 2023 TM3 is not a PHO, but is an NEO.

"Not all NEOs are potentially hazardous, but all hazardous objects are NEOs," Barstow said. "2023 TM3 has an absolute magnitude of 26.9, so its much fainter, and therefore smaller, than a PHO, so it doesn't fall into that category. Any damage would tend to be local if it didn't burn up in the atmosphere. An asteroid of this size is most likely to burn up."

2023 TM3 is extremely unlikely to hit the Earth, according to CNEOS, there is a 0.0090 percent chance of Earth impact, or around 1 in 11,000 odds. Even if it did collide with the Earth, it would likely not even make it to the ground.

"Asteroid (2023 TM3) is not a PHO," Ben-Itzhak said. "The solar system contains many objects, most of them small, in orbits that can intersect Earth's orbit, and 2023 TM3 is one of them. This means that even if it enters the Earth's atmosphere—which doesn't seem likely—it most likely will burn and break into pieces without a significant impact."

If an object large enough to be classified as a PHO hit the Earth, however, it would be a very different story.

"Not all cosmic objects present a threat to Earth. If a cosmic body [of 460 feet (140 meters) in diameter] crashed into Earth, it could destroy an entire city and cause extreme regional devastation; larger objects over 1 kilometer [in diameter] could have global effects and even cause mass extinction," Ben-Itzhak said.

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