It’s nothing to be alarmed about, but a large asteroid capable of damaging a town will on Tuesday September 1, 2020 come much closer to Earth than anyone should be comfortable with.
While most asteroids pass by beyond the orbit of the Moon, asteroid 2011 ES4 will, on Tuesday, get to a distance equivalent to between the Moon and the Earth.
How big is 2011 ES4?
2011 ES4 is a reasonably large and dangerous asteroid.
It’s about 82 feet/25 meters in diameter, so much larger than asteroid 2020 QG, which passed very close to Earth during August and was only noticed a few hours after its closest approach.
If it struck Earth it could damage a town, but not much more; think along the lines of the dramatic bolide that exploded over the city of Chelyabinsk in eastern Russia in 2014, damaging buildings and causing minor injuries.
How close did 2011 ES4 get to Earth?
This is the real headline-grabbing fact about asteroid 2011 ES4; asteroids so rarely pass by so closely. It was expected to get just 46,000 miles/75,000 kilometers from Earth; observations will—hopefully—confirm that, or cause its future trajectory to be tweaked.
The average distance between Earth and the Moon is about 239,000 miles/385,000 kilometers.
However, though 2011 ES4 got close to Earth, the 2,200+ satellites in orbit of Earth were perfectly safe. They orbit from no further than 22,220 miles/36,000 kilometers.
Could 2011 ES4 one day strike Earth?
ES4 is a near-Earth object (NEO) that could potentially strike Earth, but the chances are very. very small. According to the Center for Near-Earth Object Studies (CNEOS) there’s a 1 in 19,000 chance of the asteroid impacting Earth one day.
What is an ‘Apollo’ asteroid?
2011 ES4 is classed as an “Apollo” asteroid. It’s one of a group of near-Earth asteroids named after the first one to be discovered, 1862 Apollo, in 1932. Apollo asteroids cross Earth’s orbit so they are of particular interest.
At a whopping 1 mile/1.5 kilometers in diameter, 2011 ES4 is so big it has its own tiny asteroid moon.
Who discovered 2011 ES4?
2011 ES4 was discovered in January 2011 by the Mount Lemmon Survey, which uses a 60-inch telescope situated in the Santa Catalina Mountains northeast of Tucson, Arizona.
Wishing you clear skies and wide eyes.