A newly discovered asteroid, one believed to be up to 134 feet wide, will swing through our corner of space tomorrow for a close brush with Earth that will bring it within a few times the distance to the moon. Known as asteroid 2019 SH3, the space rock will skim Earth on Sunday night, harmlessly passing by our planet from 771,900 miles away. By comparison, the moon sits at an average distance of 238,900 miles from Earth. This means that, during tomorrow’s close flyby, the space rock will pass within 3.13 times the lunar distance.
According to a report released today by NASA’s Jet Propulsion Laboratory (JPL), the asteroid is expected to dart past Earth at 9:37 p.m. ET on September 29, exactly one week after it was first spotted by NASA asteroid trackers. During the moment of its close approach to Earth, the rock will be barreling through space at break-neck speeds of more than 31,600 mph. About four-and-a-half hours later, the wayfaring space rock will swing by the moon, flying past its cratered surface from 864,900 miles away.
Interestingly enough, tomorrow’s flyby comes a week after another 134-foot asteroid hurtled past Earth at a comparable distance of four times that between our planet and the moon.
Based on its orbit and proximity to our planet, asteroid 2019 SH3 was classified as a near-Earth object (NEO). 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.
The interesting thing about this particular NEO is that it can not only approach our planet, but also cross Earth’s orbit. Asteroid 2019 SH3 circles the sun once every three years or so, following an orbital path that occasionally allows it to cross Earth’s orbit. Due to its potential of being “Earth-crossing,” the rock was labeled as an Apollo-type asteroid — a special class of asteroids named after asteroid 1862 Apollo and which zip around the solar system on a similar orbit.
Asteroid 2019 SH3 will be preceded by a smaller 82-foot Apollo asteroid that will buzz Earth in the pre-dawn hours of Sunday morning, flying past us at 5.6 times the lunar distance.
As far as NEOs go, asteroid 2019 SH3 ranks on the smaller side. The space rock is estimated to measure anywhere between 59 feet and 134.5 feet in diameter. At the upper end of NASA’s size estimate, the asteroid would be a little over twice the size of the Chelyabinsk meteor that famously penetrated Earth’s atmosphere in 2013, exploding in the sky over Russia and wreaking havoc in the city of Chelyabinsk.
While that particular close encounter caused extensive damage — the Chelyabinsk meteor destroyed more than 7,200 buildings and injured nearly 1,500 people — tomorrow’s celestial rendezvous will pose no threat to Earth and its inhabitants. NASA assures that the asteroid will safely pass by us and then exit the inner solar system as it orbits the sun.
“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,” explains NASA.
“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.”
Tomorrow’s flyby will mark the asteroid’s first trip to our corner of the solar system. Previously, the rock performed a relatively close flyby of Jupiter more than eight decades ago, when it passed through the outer solar system in 1935. The object will return to the inner solar system in 2023 for a second visit of Earth.