NASA's Jet Propulsion Laboratory has spotted a giant "city killer" asteroid flying toward Earth. And this afternoon, it will reach its closest approach to our planet, about 1.77 million miles away.

For reference, the Moon is about 239,000 miles from Earth, so this asteroid will be 7.4 times as far from Earth as the Moon is.

The speedy space rock is expected to be zipping along at about 41,000 mph and measures roughly 890 feet across, or roughly the size of a US football stadium, according to NASA.

Experts sometimes call asteroids this size "city killers" because they're capable of destroying an entire city if they collide with an inhabited part of Earth.

Still, this asteroid will be too small and far away to see without a telescope.

It will be about 10,000 times fainter than the faintest stars visible to the naked eye, Gianluca Masi, an astrophysicist and the scientific director of the Virtual Telescope Project, told Business Insider over email.

But if you want to catch a glimpse of the asteroid as it whizzes by, you're in luck!

Masi and his colleagues will be recording the event live starting at 1 pm ET today. You can watch the livestream on YouTube or in the video below.

The livestream will track Asteroid 2008 OS7 as it flies by Earth. Viewers will be able to distinguish it as a tiny dot moving past other fixed tiny dots, aka stars, in the background. The livestream will last about 45 minutes, Masi said.

VTP has recorded other flybys like this, and it's "something always very fascinating to see," Masi told BI.

About Asteroid 2008 OS7

Asteroid 2008 OS7 orbits the Sun every 962 days. After passing by Earth, it will continue along its oval-shaped path through our Solar System.

Its oblong-shaped orbit means that each time the asteroid approaches Earth, its distance from our planet varies significantly.

For example, the website Space Reference estimates that upon its next close approach, in July 2037, it will be about 9.7 million miles from Earth.

Potentially hazardous asteroids

Asteroid 2008 OS7 is what NASA calls a "potentially hazardous" asteroid because of its size and how close it flies past Earth.

An asteroid is considered potentially hazardous if it is at least 460 feet in diameter and orbits Earth within a distance of about 4.65 million miles.

Scientists have identified more than 34,000 near-Earth objects. Just over 2,300 have been designated potentially hazardous.

But NASA suspects there are many more out there that haven't been discovered. If a giant asteroid were on course to hit Earth, we'd need five to 10 years of warning to destroy or deflect it.

NASA's Jet Propulsion Laboratory is working on the Near-Earth Object Surveyor mission, set to launch in September 2027. It would send an infrared space telescope into Earth's orbit to expand NASA's search for near-Earth objects that could threaten our planet.

This article was originally published by Business Insider.

More from Business Insider: