YouTubers filmed the speed of light at 10 trillion frames per second

In a time when a video of just about anything can go viral, it takes something truly mind-blowing to make us sit up and pay attention.

Enter the Slow Mo Guys - YouTubers known for their high-speed camera antics. In the past, they’ve captured everything you can think of in slow motion, from flying bullets to exploding melons.

But this time, they've really outdone themselves, attempting to film something that seems impossible: the speed of light.

While filming light might not sound like the most thrilling plot for a YouTube video, especially when you consider that light zips along at a blistering 300,000 kilometers per second (186,000 miles per second), this one is still worth the watch.

To put this into perspective, the Slow Mo Guys usually film at half a million frames per second, which is impressive, but not nearly enough to capture something as speedy as light.

This is where the researchers at CalTech come in, with their Compressed Ultrafast Photography department and a camera that makes the Slow Mo Guys' setup look miniscule in comparison. For one, there’s a camera in the set-up that can shoot at 10 trillion frames per second. This camera, called T-CUP, is so fast it can make just about anything look like it’s travelling in slow motion.

With T-CUP's help, the Slow Mo Guys set out to capture a laser beam traveling through a milk bottle. And why a milk bottle? Well, the milk molecules scatter the laser light, making it visible as it flies from one end of the bottle to the other in about 2,000 picoseconds. That's faster than a blink of an eye, or a hummingbird's flap, according to the YouTubers.

The result? They managed to capture the laser light moving through the bottle and guess what? It looked like an odd blue slime. Lovely.

EDUARD MUZHEVSKYI / SCIENCE PHOTO LIBRARY / Getty

“On the bottle video, the light seems to have gained the same speed so you’ve got to remember that the scale of this is much smaller,” explains one of the Slow Mo guys, Gavin Free.

“This distance here is one millimeter, whereas before it was the entire bottle, which shows you that we’re actually capturing light traveling through such a small amount of space and it’s so slow now that our picosecond has a decimal place to the hundredths femtosecond.”

While this experiment does sound like a lot of fun for no reason, it’s actually a breakthrough in the field of ultrafast photography. And T-CUP is just the beginning.

Scientists at CalTech, including Lihong Wang, one of the camera's creators, believe that they might one day develop a camera that can capture a whopping one quadrillion frames per second. That's the kind of speed that could revolutionize our understanding of the human body, he says, potentially allowing us to see tissues, including the brain, in unprecedented detail.