A Plane-Sized Asteroid Came Very Close to Earth Yesterday

Asteroid 2011 ES4 came really "close" on an astronomical scale but passed safely by on September 1st.
Chris Young

An asteroid the size of an office building flew by Earth yesterday, Sept. 1, at about a third of the distance from the Earth to the Moon.

Asteroid 2011 ES4 made its closest approach to Earth at 12:12 p.m. EDT (1612 GMT), according to NASA, when it was about 75,400 miles (121,000 kilometers) from Earth. 

Though there is some uncertainty regarding the asteroid's exact trajectory due to it largely being unobservable since 2011, the asteroid thankfully didn't come so close it was drawn into a potentially disastrous trajectory by Earth's gravity yesterday.


"Will asteroid 2011 ES4 hit Earth? No!," NASA's Asteroid Watch wrote on Twitter. "2011 ES4's close approach is 'close' on an astronomical scale but poses no danger of actually hitting Earth."

Asteroid 2011 ES4 was discovered in 2011, only two weeks before it first flew past Earth, by astronomers at the University of Arizona who were using the Mount Lemmon Survey to observe the skies.

When the space rock was first discovered, astronomers were only able to observe it for four days before it became faint, according to EarthSky.org. Due to the lack of observation data, it has been hard for scientists to calculate the asteroid's exact trajectory.

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Though 2011 ES4 has been known to the scientific community for almost a decade, it isn't out of the norm for asteroids that fly near Earth to be detected at the last moment. Only two weeks ago, for example, 2020 QG made the closest near-miss since records began, Space.com reports. It was only discovered six hours after the flyby actually took place.

For more examples, take a look at our list of huge asteroids that came scarily close to Earth, as well as this piece on the probability that the Earth could be hit by a civilization-ending asteroid.

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