An artistic impression of an Earth asteroid.
Theodore R. Kareta
A small space rock about the size of a car or truck made a slightly intrusive but not very intimidating fly on Monday.
Asteroid 2021 GW4 landed within 19,833 kilometers (19,333 kilometers) of the Earth in the Pacific Ocean on Monday morning, according to the Harvard astronomer.
Asteroid 2021 GW4 moves within the GEO band from 1146 UTC to 1416 UTC 12 April. Perigee is 19833 km. Fortunately, the space is still empty at these heights – my estimate is that the closest approximation of an object detected is 1009 km from the object S26918 pic.twitter.com/FJReTeK0ll
– Jonathan McDowell (@ planet4589) 12 April 2021
It places the asteroid well inside the ring where many large artificial satellites orbit the earth at an altitude of 22,236 miles (35,786 kilometers).
“Fortunately, the space is still empty at these heights,” McDowell wrote on Twitter.
He estimated that the closest functioning satellite to the asteroid’s path was a military GPS satellite about 2,243 kilometers away.
NASA estimates the asteroid’s diameter to be between 3.5 and 7.7 meters. It’s small enough that the whole thing is likely to burn if it collides with our atmosphere.
2021 GW4 was originally launched on April 8 by the Mt. Lemmon Survey in Arizona, another example of improving the ability of such surveys to spot even very small asteroids passing very close. Often such space rocks are only discovered hours before their nearest neighbor passes, or even when they are already in our planetary rearview mirror.
So far in 2021, only two asteroids have come closer to the surface of our planet. But like the vast majority of all objects in our immediate cosmic environment, no one has ever posed a real threat.
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