A rather small asteroid — one believed to measure only as much as 55.7 feet across — will skim Earth tomorrow on a very close approach, scientists at NASA’s Jet Propulsion Laboratory (JPL) have announced. The relatively small space rock was just recently discovered and is currently bound for Earth, due to cruise past us on Sunday afternoon at a couple of times the distance to the moon.
Dubbed asteroid 2019 SG1, the wayfaring space rock was first picked up by NASA asteroid trackers on Friday. Based on its trajectory and proximity to our planet, the rock was immediately flagged as a near-Earth object (NEO) and classified as an Apollo-type asteroid.
As NASA explains, NEOs are celestial objects such as comets or asteroids that orbit somewhere between approximately 91 million and 121 million miles from the sun. This means that, in their journey around the sun, NEOs can venture as far as roughly 30 million miles away from Earth’s orbit and as close to the planet’s surface as a few times the distance to the moon — or even closer.
Aside from being a NEO, 2019 SG1 is also an Apollo asteroid. This specific classification is closely related to the asteroid’s orbit around the sun and signifies that it has the potential of being “Earth-crossing.” Named after asteroid 1862 Apollo, space rocks of this class zip around the solar system on an orbital path that occasionally allows them to cross Earth’s orbit, NASA says. One such instance will occur on Tuesday when a massive 1,410-foot Apollo asteroid is expected to cross Earth’s orbit and come as close as 2.58 million miles from the planet’s surface.
While nowhere near as large as next week’s celestial visitor, asteroid 2019 SG1 will creep in a lot closer to Earth tomorrow. The rock is expected to swoop in for its close approach at 5:08 p.m. EDT on September 22 and harmlessly fly past Earth at a distance of 520,800 miles. To put that into perspective, that’s 2.21 times the distance between Earth and the moon.
Although the asteroid was first spotted only one day ago, NASA has had enough time to calculate its orbit. The agency assures that the upcoming flyby will be a perfectly safe one.
“Scientists determine the orbit of an asteroid by comparing measurements of its position as it moves across the sky to the predictions of a computer model of its orbit around the sun,” NASA explained last week.
“The more observations that are used and the longer the period over which those observations are made, the more accurate the calculated orbit and the predictions that can be made from it.”
In the case of asteroid 2019 SG1, JPL scientists used 22 observations to gauge its orbital path and plot its course through the inner solar system.
As far as NEOs go, asteroid 2019 SG1 is not a particularly hefty one. The rock is estimated to measure at least 24.2 feet in diameter and can be up to 55.7 feet wide, per NASA’s Center for Near-Earth Object Studies (CNEOS).
During its close approach to Earth, the asteroid will be hurtling through space at a dizzying speed of nearly 39,000 mph. That’s more than 50.8 times the speed of sound.
Tomorrow’s close brush with Earth will be the first-ever trip through the inner solar system for the fast-zipping asteroid. About a couple of hours after its flyby of Earth, the rock will swing by the moon, coming within 353,400 miles of its crater-pockmarked surface.
The traveling asteroid is not likely to return to our cosmic neighborhood in the foreseeable future.