spaceSpace and PhysicsspaceAstronomy

Asteroid As Large As A Mountain Will Fly Near Earth This Weekend


Dr. Alfredo Carpineti

Senior Staff Writer & Space Correspondent

clockAug 20 2021, 10:54 UTC
asteroid near earth

Artist's impression of an asteroid near earth. Image Credit: Dima Zel/

On Saturday, August 21, a potentially hazardous asteroid will safely fly past Earth at a distance of just 3.4 million kilometers (2.1 million miles), the closest approach for several decades. That’s just 8.9 times the distance between the Earth and the Moon.

Asteroid 2016 AJ193 is larger than 99 percent of all known Near-Earth objects and so it is good to keep an eye on it.


The space rock measures 1.37 kilometers (0.85 miles) according to measurements from NASA’s spacecraft NEOWISE. It is also surprisingly dark, reflecting very little light back making this close (and safe) approach an important chance to better study the object.

It was discovered by the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) facility – located at Haleakala Observatory, Hawaii in January 2016. It is important to stress that an asteroid with the potential to devastate our planet was only discovered five years ago.

The asteroid orbits around the Sun every 5.9 years going far beyond the orbit of Jupiter and then as far as the orbit of Venus, with quite the inclination with respect to the plane of the solar system. Its next really close passage to Earth will be August 19, 2080, where the asteroid will be at about twice the distance that it will be on Saturday.

The orbital path of 2016 AJ193 around the Sun. Image Credit: NASA/JPL-Caltech

Professional astronomers will study this object using the Goldstone Observatory in California together with observatories in Spain, Germany, Italy, and Russia. The observations will cover the period August 20 to August 24, roughly the time that it is observable for them.

But if you are passionate about astronomy and you have a telescope, you to can look for it in the sky. Despite its dimness, astronomers expect that it should brighten to at least the 14th magnitude during its close approach.


Telescopes of 20 centimeters (8 inches) or larger should be able to spot it. It will appear in the constellation of Lepus, near the Mu Leporis star. Better watch it just before dawn.


“Not only is 2016 AJ193 a near-Earth asteroid, but it is too classified as a Potentially Hazardous Asteroid. The flyby from a roughly 1-mile (~1.4 kilometers) large body does not only require specific attention, but it is also a clear reminder of the importance of building a community of observers capable of observing the sky from everywhere and all the time,” Franck Marchis, chief scientific officer at Unistellar, told IFLScience.

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