Later this month, planet Earth is in for a momentous close encounter with a massive asteroid, one that could potentially dwarf the Empire State Building and even the One World Trade Center in Manhattan. Known as asteroid 162082 (1998 HL1) — or 1998 HL1, for short — the giant space rock is estimated to be as much as 3,250 feet wide and has been labeled by NASA as potentially dangerous.
The formidable space rock will swoop in for a close approach to Earth on October 25, barreling past our planet at a break-neck speed of a little over 25,000 mph, scientists at NASA’s Jet Propulsion Laboratory (JPL) announced today. However, NASA assures that there’s no reason to panic, as the asteroid will only come within a few million miles from the planet’s surface.
Asteroid 1998 HL1 is the second largest space rock to come this close to Earth in 2019, after a nearly mile-wide asteroid buzzed by Earth on May 25 — exactly five months before the upcoming close brush that should happen in late October. According to NASA’s Center for Near-Earth Object Studies (CNEOS), the colossal asteroid is thought to be at least 1,443 feet across and can measure up to 3,248 feet in diameter. At the upper end of NASA’s size estimate, the rock is about 2.2 times bigger than the Empire State Building and almost two times larger than the famous 1,650-foot asteroid Bennu, which is currently being orbited by NASA’s first asteroid-sampling mission, the OSIRIS-Rex.
As its name suggests, the behemoth was discovered 21 years ago — on April 14, 1998, to be exact — when it was picked up by asteroid trackers at NASA’s Lincoln Near-Earth Asteroid Research project (LINEAR) near Socorro, New Mexico. The space agency has been keeping a close eye on the massive asteroid ever since, carefully studying its orbit around the sun to determine how close it may get to Earth as it zips around the giant star once every 508 days.
Based on its orbital path, asteroid 1998 HL1 has been classified as an Apollo-type asteroid. This indicates that the massive rock has the potential of being “Earth-crossing,” meaning that it circles the sun on an orbit that allows it to occasionally intersect Earth’s own orbit.
Due to its towering size and proximity to Earth, the rock has also been flagged as a “potentially hazardous asteroid” (PHA). In order to qualify as a PHA, an asteroid has to measure at least 460 feet in diameter and follow an orbital path that brings it within 4.66 million miles of Earth. Based on JPL data, asteroid 1998 HL1 will approach Earth a lot closer than that when it swings by on October 25.
The huge asteroid is expected to approach the planet in the early hours of the afternoon. As it darts through the inner solar system on its way around the sun, the rock will reach its closest point to Earth at 1:21 p.m. ET on October 25, when it will pass within 3.85 million miles of the planet’s surface. To put that into perspective, that’s 16.17 times the distance to the moon.
While a close brush with an asteroid — particularly one so large — can certainly be unnerving, there is no cause for concern. NASA assures that the giant asteroid poses no risk of hitting Earth and will harmlessly fly past our planet and continue its journey around 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.”
In the case of asteroid 1998 HL1, JPL scientists have used a total of 504 observations spanning two decades, the most recent one performed yesterday.
The upcoming close encounter with the massive asteroid will be one for the records. The giant space rock hasn’t come this close to Earth in 32 years — it passed within 4 million miles of the planet’s surface on October 26, 1987.
Asteroid 1998 HL1 has already passed once through our neck of the cosmic woods this year. The rock swung by for a close flyby in mid-June, when it buzzed by Earth from a staggering distance of 34.7 million miles away.
The asteroid will return in 2026, and then again in 2030 and 2037. In 2044, it will perform another double flyby of Earth, just like it did this year, shooting past our planet both in late May and in early November. However, the rock won’t approach at a comparable distance of 4 million miles until October 25, 2051, according to predictions from the JPL.