Peanuts! Get your peanuts here! The Solar System has been passing out peanuts lately in the form of two different oddly shaped asteroids that recently passed by Earth, and both look like over-sized peanuts. The latest peanut-shaped asteroid pass was on September 16, 2024, when the near-Earth asteroid 2024 ON came within 1 million kilometers (62,000 miles) of Earth (2.6 times the Earth-Moon distance). Radar imaging revealed the asteroid was peanut-shaped because it is actually a contact binary – which means it is made of two smaller objects touching each other. NASA says the two rounded lobes are separated by a pronounced neck, and one lobe about 50% larger than the other.
In total, 2024 ON measures about 350 meters (382 yards) long. The radar could resolve features down to about 3.75 meters across on the surface, including brighter boulders. NASA says about 14% of asteroids in this size range (larger than about 200 meters (660 feet)) are contact binaries.
Just last month, on August 18-19, 2024, the other “peanut” passed by our planet. Asteroid 2024 JV33 appears to also be a contact binary with two rounded lobes, one lobe larger than the other, and is about 300 meters (980 feet) long, about as long as the Eiffel Tower. Imagery showed that asteroid 2024 JV33 rotates once every seven hours. It safely passed Earth a little further than 2024 ON, at a distance of 4.6 million km (2.8 million miles), about 12 times the distance between the Moon and Earth.
Both asteroids were captured in a series of radar images obtained by the Deep Space Network’s Goldstone Solar System Radar near Barstow, California. The principal technique for studying asteroids is radar – called planetary radar. While astronomers can study the Universe by capturing light from stars, planets, and galaxies, they can also study nearby objects by shining radio light on them and analyzing the signals that echo back. Planetary radar can reveal incredibly detailed information about our planetary neighbors.
“When astronomers are studying light that is being made by a star, or galaxy, they’re trying to figure out its properties,” said Patrick Taylor, radar division head for the National Radio Astronomy Observatory, in an interview I did with him earlier this year. “But with radar, we already know what the properties of the signals are, and we leverage that to figure out the properties of whatever we bounced the signals off of. That allows us to characterize planetary bodies – like their shape, speed, and trajectory. That’s especially important for hazardous objects that might stray too close to Earth.”
An animation of the radar images showing the rotation of asteroid 2024 ON. Credit: NASA/JPL. 2024 ON was discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) on Mauna Loa in Hawaii on July 27. The asteroid was discovered by the Catalina Sky Survey in Tucson, Arizona, on May 4.
NASA labels objects larger than 492 feet that come within 4.6 million miles of Earth “potentially hazardous objects,” so scientists are monitoring 2024 JV33 for potential danger even though they don’t expect the asteroid to pose a threat in the future.
