An Asteroid the Size of a Skyscraper Just Flew by Earth (Video)

An enormous asteroid flew by Earth today (Oct. 25), and you can watch it zip by in a video from the Virtual Telescope Project.

Asteroid 1998 HL1 was 3.86 million miles (6.21 million kilometers) away from Earth — about 10 times the average distance to the moon — when it makes its closest approach at 1:17 p.m. EDT (1717 GMT), according to NASA.  

The Virtual Telescope Project, an online observatory founded by astrophysicist Gianluca Masi of the Bellatrix Astronomical Observatory in Ceccano, Italy, hosted a live webcast about the asteroid during the close encounter today. You can watch a replay here at the Virtual Telescope Project's website.

Video: Giant Asteroid 1998 HL1 Seen by Virtual Telescope Project
Potentially Dangerous Asteroids (Images)

Gianluca Masi of the Virtual Telescope Project captured this image of the potentially hazardous asteroid 1998 HL1 on Oct. 23, 2019, at 1:41 p.m. EDT (1741 GMT), when the asteroid was about 4.1 million miles (6.6 million kilometers) away from Earth. The image comes from a single 300-second exposure captured remotely using the Virtual Telescope Project’s Elena telescope. The telescope tracked the asteroid’s movement, so the asteroid appears as a white dot in front of a background of star trails.  (Image credit: Courtesy of Gianluca Masi/The Virtual Telescope Project)

NASA classifies asteroid 1998 HL1 as "potentially hazardous" because the space rock has the "potential to make threatening close approaches to the Earth." That doesn't mean the asteroid poses a threat this time around. The agency defines all asteroids whose orbits around the sun come within 4.6 million miles (7.8 million km) of Earth's orbit, and that have a diameter of at least 500 feet (meters) as "potentially hazardous asteroids."

Asteroid 1998 HL1 measures about 1,800 feet (550 m) in diameter, or about the height of the Sears Tower in Chicago, according to NASA's Jet Propulsion Laboratory. "This will make it quite bright around the time of the flyby," Masi wrote in a description of today's webcast

This sky chart from the Virtual Telescope Project shows the path of asteroid 1998 HL1 through the night sky from Oct. 25 to Oct. 28. (Click the top right corner of the image to expand it.) (Image credit: Gianluca Masi/The Virtual Telescope Project)

Today's flyby will be the closest one until Oct. 26, 2140, when it will be just slightly closer to Earth at a distance of 3.84 million miles (6.18 million km). So, 1998 HL1 won't pose a real threat to Earth for the foreseeable future. 

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Hanneke Weitering
Contributing expert

Hanneke Weitering is a multimedia journalist in the Pacific Northwest reporting on the future of aviation at and Aviation International News and was previously the Editor for Spaceflight and Astronomy news here at As an editor with over 10 years of experience in science journalism she has previously written for Scholastic Classroom Magazines, MedPage Today and The Joint Institute for Computational Sciences at Oak Ridge National Laboratory. After studying physics at the University of Tennessee in her hometown of Knoxville, she earned her graduate degree in Science, Health and Environmental Reporting (SHERP) from New York University. Hanneke joined the team in 2016 as a staff writer and producer, covering topics including spaceflight and astronomy. She currently lives in Seattle, home of the Space Needle, with her cat and two snakes. In her spare time, Hanneke enjoys exploring the Rocky Mountains, basking in nature and looking for dark skies to gaze at the cosmos.