Asteroid That May Be As Tall As Golden Gate Bridge to Zip Past Earth This Weekend

A large asteroid that could be taller than the Golden Gate Bridge is set to zip past Earth this weekend.

The space rock, dubbed 2021 PT, is scheduled to make a close approach to our planet on Saturday, according to NASA's Center for Near Earth Object Studies (CNEOS.)

At 8:52 p.m. ET (5:52 p.m. PT), the asteroid will come within around three million miles of our planet, which is equivalent to around 12 times the average distance between the Earth and the moon.

During its flyby, the asteroid will be traveling at roughly 16,200 miles per hour—about eight times as fast as a rifle bullet.

Based on the asteroid's observed magnitude, the CNEOS estimates that the object measures anywhere between 360 and 787 feet in diameter.

At the upper end of this scale, the asteroid would stand slightly taller than San Francisco's Golden Gate Bridge.

At the lower end, the asteroid would measure slightly longer than a football field, or slightly smaller than the height of the Great Pyramid of Giza in Egypt.

2021 PT is one of many near-Earth objects (NEOs) that scientists have discovered. An NEO is any astronomical body—mostly asteroids but some comets as well—that pass within 30 million miles of Earth's orbit.

To date, astronomers have identified more than 26,000 NEOs. According to the CNEOS, more than 90 percent of those larger than one kilometer (0.62 miles) in diameter have already been discovered.

Some NEOs are also classified as "potentially hazardous" if they meet certain criteria, namely, they are estimated to measure more than 140 meters (460 feet) in diameter and are predicted to come within 4.6 million miles of the Earth's orbital path.

So far astronomers have identified more than 2,200 NEOs that are considered to be potentially hazardous. But this does not necessarily mean that they pose an imminent risk to Earth.

"The potentially hazardous designation simply notes that it is an important one to track and verify as zero," Richard Binzel, a planetary scientist from the Massachusetts Institute of Technology, previously told Newsweek.

According to Alan Fitzsimmons from the Astrophysics Research Centre at Queen's University Belfast in Northern Ireland, the current risk to any single person from an asteroid strike in the foreseeable future is low, but "non-zero."

"The risk from impact over the next 100 years or more has diminished because of decades of work by (mainly U.S.) scientists, ruling out an impact of the largest kilometer-scale asteroids in the next 100 years," he told Newsweek.

"There are a couple of very small asteroids a few metres across that have a one percent-five percent chance of hitting us, but they would burn up in the atmosphere."

An asteroid
Stock image showing an asteroid making a close approach to Earth. This weekend, a large asteroid that could measure nearly 800 feet in diameter will zip past Earth. iStock