Blurry new photos of a ‘planet-killing’ asteroid the size of a mountain recently made its closest approach to Earth in more than a century have discovered a surprising new feature of the giant space rock – it has a secret mini-moon.
Asteroid 2011 UL21 is one potentially dangerous, a near-Earth object previously estimated to be somewhere between 1.1 and 2.4 miles (1.7 to 3.9 kilometers) across, making it larger than 99% of near-Earth asteroids. At this size, it would likely wipe out an entire continent and cause devastating climate change on a global scale, earning it the killer of the planet designation. However, it is not predicted to hit Earth in the future.
On June 27, 2011, UL21 reached its closest point to Earth in at least 110 years, when it zipped past 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 likely makes it one of the 10 largest asteroids to pass so close to Earth since 1900, according to astrophysicist Gianluca Masi. The virtual telescope project in Italy.
Scientists at NASA’s Goldstone Deep Space Communications Complex in California monitored the historic flyby using the Goldstone Solar System Radar Telescope. The team shot grainy “bistatic” images of the giant rock by bouncing radio waves off its surface, which revealed two things: First, the space rock is probably only about 1 mile (1.6 km) wide; and second, there was a second, smaller asteroid orbiting 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 photos revealed that this recently discovered space rock was knocked out of the way by the close encounter.
of new images from both asteroids were launched on July 3 from NASA’s Jet Propulsion Laboratory (JPL).
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2011 The newly discovered minimoon of UL21, which has not been named, is what researchers call a small-body satellite — an asteroid that orbits another larger asteroid or dwarf planets. It’s unclear from the images how big the new space rock actually is, but it’s likely to be significantly smaller than 2011’s UL21.
The two asteroids form what is known as a binary system and are separated by a distance of about 1.9 miles (3 km), according to JPL.
Small body satellites are The most common types of natural satellites in the solar systemand are especially common around such large asteroids.
“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 mutual orbits, masses and densities, which provide key information about how they may have formed,” Lance Bennera JPL scientist who led the latest 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 proved. this is the case with the Dinkinesh asteroid.
The next time we’ll get a good look at 2011 UL21 and its newfound companion will be 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 its current approach.