A Huge 656-Foot Asteroid Will Shoot Past Earth Today At 28,000 MPH

This will be the space rock's closest approach to our planet in 55 years.

A near-Earth asteroid approaching our planet.
urikyo33 / Pixabay

This will be the space rock's closest approach to our planet in 55 years.

A huge asteroid — one estimated to be larger than the Great Pyramid of Giza in Egypt — is due to cruise by Earth later today, NASA has announced. The giant rock will harmlessly pass by our planet in the late hours of the evening, flying at a safe distance of a little more than 4.4 million miles. While the encounter is still considered a close brush in astronomical terms, NASA assures that there is no reason to panic. The sizeable asteroid poses no danger to Earth and will perilously fly past us as it laps around the sun.

The pyramid-sized asteroid is known as 2015 BK509. As its name suggests, the rock was discovered a few years ago and has been on NASA’s radar since early 2015. The object is classified as an Apollo-type asteroid — a class of space rocks that can cross Earth’s orbit as they zap around the solar system — and has been extensively monitored over the past five years. Scientists have studied the rock’s position across the sky to calculate its orbit over the course of 156 observations, the last one of which was carried out yesterday. Orbital data gathered by NASA’s Jet Propulsion Laboratory shows that 2015 BK509 swings around the sun once every 1.25 years, frequently passing by Earth — and sometimes by Venus — as it circles the giant star.

Today’s visit will see the rock approaching Earth at speeds of just under 28,000 mph. NASA predicts that the asteroid will reach its closest point to our planet at 7:29 p.m. ET, when it will buzz Earth from more than 18.6 times the distance to the moon.

Asteroid 2015 BK509 is among the heftier Apollo asteroids to wander through our neck of the cosmic woods in recent weeks. The near-Earth asteroid is believed to measure anywhere between 288 feet and 656 feet in diameter, per NASA’s Center for Near-Earth Object Studies (CNEOS). At the upper end of the size estimate, the rock is 1.4 times bigger than the iconic Egyptian pyramid, and more than twice the size of the Statue of Liberty in New York. Even at the lower end of NASA’s size estimate the asteroid is large enough to pose concern should it venture too close to Earth. Thankfully, that won’t be the case today, as the rock will perform a completely safe flyby of our planet — just as it has done numerous times before.

A near-Earth asteroid approaching our planet.
  urikyo33 / Pixabay

The asteroid has been coming around to our corner of space for a long time. JPL scientists have unraveled its history of close Earth approaches all the way back to the year 1903, revealing no less than 45 flybys of our planet in the past 117 years. The last time 2015 BK509 visited Earth was in 2016, when it barreled past us at more than 52,000 mph but only came some 29.7 million miles from the planet’s surface.

Interestingly enough, today’s encounter will be the closest one in more than half a century. Its previous record-close approach occurred on September 12, 1965, and brought the rock within 3.1 million miles of the terrestrial surface. The closest that the asteroid has ever gotten to Earth was on February 26, 1954, when it missed our planet by 2.2 million miles.

The giant space rock is expected to return next year, and then again in 2025, 2026 and 2030. JPL scientists have calculated its future close approaches up until the year 2200 and predict a total of 69 Earth flybys between now and then.