A Skyscraper-Sized Asteroid is about to Whizz Past Earth today on the Fall Equinox

An asteroid discovered earlier this year will come closest to Earth tonight, coincidentally at the same time as the globe is experiencing day and night. Although there is no chance of a collision because 2021 NY1 will never get closer than the Moon, the occurrence serves as a reminder that the Solar System is a perilous environment where we don’t know everything. The length of 2021 NY1 is between 130 and 300 meters (420-990 feet), with a height of between 30 and 80 stories. It isn’t a dinosaur killer at that size, but if it hits the earth, it might cause major local damage.

It’s probably certainly bigger than the item that burst above the Dead Sea earlier this week, maybe inspiring the Biblical account of the destruction of Sodom and Gomorrah. In this scenario, though, we don’t need to be concerned about fire and brimstone falling from the sky. Up to 2192, the close approaches of 2021 NY1 have been sketched out, and none of them are particularly close. In fact, at 2:41 p.m. UTC today, it will be the closest it will get to us during that time, at just over 1% of the distance between the Earth and the Sun, or 1.5 million kilometers (932,000 miles), four times the distance to the Moon.

The next time 2021 NY1 gets close is in 2044 when it will be about four times further away than it is now, however it will be nearly as close in 2105 if anyone expects to see it.

The orbit of the 2021 NY1 spacecraft sends it well past Mars, nearly 2.5 times as distant from the Sun as the Earth ever gets. Its closest approach to the Sun is 1% inside the Earth’s orbit, which is significant from our perspective.

Near-Earth Objects (NEOs) like this one come quite close to Earth on a regular basis. It’s only been a month since a much larger one flew by at almost twice the distance. In that case, though, we had known about it for five years.

As the name implies, 2021 NY1 was discovered only this year, in June to be exact. It’s again another reminder that there are a lot of NEOs out there that we’re not aware of, and that if one is headed our way, we might not get much notice. The fact that 2021 NY1’s close approach coincides with the equinox when both hemispheres have 12 hours of day and night regardless of distance from the equator, distinguishes it from other asteroids.

The (Northern Hemisphere) autumnal equinox occurs this year on September 22 at 3:20 p.m. EDT (7:20 p.m. UTC), therefore the asteroid will arrive nearly five hours early.