Blurry new photos of a ‘planet-killing’ mountain asteroid that has recently come closest to Earth in more than a hundred years have revealed a surprising new feature of a gigantic space rock – it has a secret mini-moon.
Asteroid 2011 UL21 is a potentially dangerous, a near-Earth object previously estimated to be somewhere between 1.7 and 3.9 kilometers wide, making it larger than 99% of near-Earth asteroids. At this size, it could probably wipe out an entire continent and cause devastating climate change on a global scale, earning it planet killer nickname. However, it is not expected to hit Earth in the future.
On June 27, 2011, UL21 reached its closest point to Earth in at least 110 years when it flew by our planet at more than 58,000 mph (93,000 km/h). The giant space rock reached a minimum distance of about 4.1 million miles (6.6 million kilometers) — about 17 times farther from our planet than the Moon. That probably makes it one of the 10 largest asteroids to pass this close to Earth since 1900, according to astrophysicist Gianluca Masi Virtual telescope project in Italy.
Scientists at the Goldstone Deep Space Communications Complex in California tracked the historic flyby using the Goldstone Solar System Radar telescope. The team took grainy “bistatic” images of the giant rock by bouncing radio waves off its surface, revealing two things: First, the space rock is probably only about 1.6 km wide; and secondly, a second smaller asteroid orbits it.
Two days later, on June 29, the same telescope also captured images of the pyramid-sized asteroid 2024 MK. passed our planet closer than the moon. These images revealed that this recently discovered space rock was thrown off course by the close encounter.
The new pictures Both asteroids were launched on July 3 by NASA’s Jet Propulsion Laboratory (JPL).
Related: No, NASA didn’t warn of an impending asteroid strike in 2038. Here’s what really happened.
The newly discovered 2011 minimoon UL21, which has not been named, is what scientists call a small-body satellite — an asteroid that another larger asteroid is orbiting or a dwarf planet. It’s not clear from the images how big the new space rock really is, but it’s likely significantly smaller than UL21 from 2011.
The two asteroids form what is known as a binary system and are separated by a distance of about 3 km, according to JPL.
Small body satellites are the most common types of natural satellites in the solar systemand are especially common in asteroids this large.
“About two-thirds of asteroids of this size are thought to be binary systems, and their discovery is particularly important because we can use measurements of their relative positions to estimate their relative orbits, masses and densities, providing key information about how they may have formed, ” Lance Bennerthe JPL scientist who led the recent observations said in a statement.
It’s also possible that the newly discovered moon is actually two separate small-body satellites in close proximity, as NASA’s Lucy mission recently demonstrated. this is the case of asteroid Dinkinesh.
We’ll next take a good look at 2011 UL21 and its newfound companion in 2089, when the space rocks will come within 1.7 million miles (2.7 million km) of our planet—about two and a half times closer to us. than his current approach.