That's a near-miss in astronomical terms, but not close enough to impact Earth, according to NASA. It is expected to draw closer to Earth than any similar-sized object has since 2006.

The asteroid is about the size of a large skyscraper and traveling unusually fast, about 78,000 miles per hour. While it won't be visible with the naked eye, astronomers say space enthusiasts should be able to see the asteroid with a decent telescope.

As for timing, NASA expects the asteroid to be observable at approximately 5:18 p.m. EST on Halloween.