Last week, an asteroid pair came dangerously close to Earth, posed for some pictures and left!

Ever seen those videos of celebrities stepping out of a cafe on a regular day while the paparazzi would go crazy with their cameras, snapping pictures at speeds that you wouldn’t think were possible? Just last week, asteroids that were similarly going about their business got some celebrity-treatment from NASA.

Not one, but two large asteroids, zoomed past Earth in a rare double flyby. Thankfully, neither 2024 MK nor 2011 UL21 posed any threat, but they did give scientists a chance to snap some incredible close-up images.

By studying these images, researchers can learn more about the makeup of these space rocks, which is crucial for planning how to deal with any future asteroids that might be a little too enthusiastic about visiting our planet.

Our solar system is vast and mostly empty, but every now and then, an asteroid or comet swings by on its cosmic journey. Most of these are harmless, but some get flagged as "potentially hazardous" if they get too close or are big enough.

That's because even if their current path is safe, a future bump with another space object could send them on a collision course with Earth. It's unlikely, but hey, better safe than sorry!

Luckily for us, both 2024 MK and 2011 UL21 came in peace and were more than happy to be papped. 2011 UL21 cruised by on June 27th at a comfortable distance of 17 times the Earth-Moon distance. Then, just two days later, 2024 MK made its appearance, getting a bit closer at about three-quarters of the Earth-Moon distance.

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Capturing clear images of these celestial visitors is no easy feat. Even though they're considered "large" asteroids, they're still relatively small and faint in the grand scheme of space.

That's where NASA's awesome radar telescope comes in. It beams radio waves out into space, and by analysing the bounced-back signal, scientists can create detailed images.

Since 2024 MK buzzed by much closer (these close encounters only happen every few decades or so), we were able to get a much more detailed look. The images revealed a 500-foot-long, elongated asteroid with a bumpy, ridged surface. It even tumbles as it travels through space!
This rock was only discovered on June 16, and Earth's gravity actually nudged its orbit a bit. Studying these observations will help scientists predict 2024 MK's future path, and good news – it looks like it'll stay safely out of our way for the foreseeable future.

Astronomer Lance Benner of NASA's Jet Propulsion Laboratory thinks that this was an amazing opportunity to get up close and personal with a near-Earth asteroid. While the images of 2011 UL21 weren't quite as detailed due to the distance, they did hold a bit of a surprise – a tiny moon orbiting the 1.5-kilometer-wide asteroid!

This isn't the first time we've spotted a miniature moon companion with a large asteroid. In fact, it seems to be happening more and more often as our observation technology improves. This is fantastic news for both planetary defence and understanding how our solar system formed.

"It is thought that about two-thirds of asteroids of this size are binary systems," Benner explains, "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."

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