Filming the Speed of Light at 10 Trillion FPS

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It didn't really hit me how insane this is until he said that if there were to do this same experiment with a bullet, it would take years for it to travel through the shot. Incredible.

👍︎︎ 77 👤︎︎ u/Skoges 📅︎︎ Mar 27 2019 🗫︎ replies

are they using different techniques then what the MIT was doing?
here you see it much clearer and get a good sense of refraction/dispersal going on:
https://www.youtube.com/watch?v=EtsXgODHMWk

👍︎︎ 22 👤︎︎ u/MissStabby 📅︎︎ Mar 27 2019 🗫︎ replies

I cant watch the video fully but ive seen something like this before. aren't they just taking "pictures" many times at different delays past many similar light pulses?

👍︎︎ 4 👤︎︎ u/f3l1x 📅︎︎ Mar 28 2019 🗫︎ replies

Amazing. Absolutely, amazing.

👍︎︎ 1 👤︎︎ u/moondusterone 📅︎︎ Mar 28 2019 🗫︎ replies

Exactly the abilities of my gear!!!!lol

👍︎︎ 1 👤︎︎ u/mpalin69 📅︎︎ Mar 28 2019 🗫︎ replies

wow nice video

👍︎︎ 1 👤︎︎ u/andrewgodlike 📅︎︎ Mar 28 2019 🗫︎ replies

How is it possible to film faster than light?

👍︎︎ 1 👤︎︎ u/razorbackgeek 📅︎︎ Mar 27 2019 🗫︎ replies

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Today, we're at CalTech, because in a building over there is a camera that absolutely blows my mind. Now, we've filmed at some very high frame rates. We're talking up to about half a million, which is... - Not to be sniffed at. - ...serious frame rates. Their camera puts ours to shame and does 10 trillion frames per second. That's 13 zeroes. For reference, that is 20 million times faster than the fastest we've ever filmed on this channel. And there's not much you can't film with half a million frames a second, but one of those things is the speed of light. - Not a bad subject. - No. - Let's get in there. - All right. Even the shoe cover technology is cool. I kind of want one of these at home, actually. - Just for people. - All right, let's go in, see what this CUP is all about. - Nice to meet you. - Man: Nice to see you. - How's it going? - Good. So, what's actually-- what are we doing here? This looks all very complicated. Oh, this is the world's fastest camera. Oh, okay. Yeah. This is the world's fastest camera. There you go. Just as easy as that. How big is the actual camera part? I can show you. That big box is the camera itself. And here is the optics that we designed - to make the thing work. - Very cool. A lot of times in our YouTube comments, we get asked to film the speed of light. And I have to always reply to people letting them know that the speed of light, it's almost incomprehensibly fast, and even our cameras, under a million frames a second, will never see anything like that. Is this camera capable of filming the speed of light? Yeah, that's basically what we are gonna see. For the example I'm going to show, the light will move about the length of this bottle. In time, how long does it take for light to start here and end here? It takes about 2,000 picoseconds. - That's pretty quick. Yeah. - Pretty quick. So for the audience, it goes milliseconds, microseconds... - Is it nano-- - ...nanoseconds, - picoseconds, femtoseconds. - Yes. So we're on the sort of pico/femto scale with this stuff. - We've never done that before, for sure. - Yeah, no. This is completely on another level. Shall we set up the first experiment? - Sure, yeah. - Start with the bottle? - Everyone should wear laser goggles. - Goggles? - Okay. - Peng: We have some. - Do I look good? - You've got side panels in your glasses. - You look like you're about to-- - You look bad-ass. It looks like you're about to go skiing with a welding torch. It's just... So, I assume because we're trying to film light, it'll be useful to turn all the lights off in here, right? - Yes. - Otherwise, we'll just get... All the ambient light comes, yeah. Right. Okay. Let's get ready for lights off. Yeah. - Can you hold this for me? - I'll hold this. - Yeah, thank you. - I'm excited. I get giddy by this frame rate stuff. We want to see the light propagation from the side, so we need to make sure that the light is scattered out of the plane of view through the milk molecules inside, then you can see light scatter from the side. So, this is a bottle full of water with a bit of milk in? So, I am going to turn on the laser. So all you do is just move mirrors and lenses around and then it goes to different areas? We use that to move the laser. The laser's too big. See, the light hits the bottom of the bottle. So it goes through the bottle. - Is it a powerful laser? - It's very powerful. It can basically burn any, like, papers. - I will stay away from that. - Yeah. - Whoa, that's cool. - You can see its glow. The first thing I'm going to capture is the static image as our reference. For today, I'm going to try... - Excellent. - Yeah, yeah. I mean, I remember when I was excited when we started shooting, we moved from 1,000 frames a second - to 28,000 frames a second. - That was a big jump. Okay, we're pretty much done with the water bottle. I'd like to take a photo of this. As you can see, we can only see the light. We cannot see the bottle and the label on it. - Yeah. - So, finally, in the movie, we may want to overlap both the bottle itself and the light. - Like, composite a real picture. - Yeah, yeah. So you just take a photo on your phone and that can-- you can do that? Yeah, you can just use software to overlap these two things. - Gav: Neat. - Dan: You're in the photograph. Just photo-bombing the bottle. Okay, let's watch back our bottle. This took eight hours to process, during which time I grew a slightly longer beard. I had a haircut as well. All right, here we go. Dan: Okay, so what we're seeing here is the bottle's just been comped in, basically. Gav: Yeah, this camera only detects the light itself, which is like a blue-ish laser light, which is why you don't really see anything else other than the light looking like that. And then we comp in the picture of the bottle. In the room with my actual eye, it looked like it was constantly lit up, but here we're able to follow the light moving through the bottle. It may not look like it, but this is actually real. Dan: It's refracting the photons and that's why you can see it. But when it's just going through the air, there's nothing to actually reflect the light. Gav: Yeah, it's only showing up in the bottle. It is interesting. It almost looks like sort of an '80s film effect. It does, doesn't it? It looks like-- Like some sort of ghost flying into the room. But actually, that is light. Gav: Isn't that weird? Look at the scale. Every frame seems to be ten picoseconds. And we're just sort of casually watching this light go left to right through the bottle, but in reality, the light is moving a million times faster than a bullet. - Dan: What a mental subject. - Yeah. Gav: Okay, so we've shot light through milk. - Next experiment? - Yep. For this experiment, we designed a special cavity. We call it a chaotic cavity. When light comes in the cavity, it will bounce back and forth multiple times by the mirrors surrounding in the cavity. - You're almost trapping light inside the-- - Yeah. Yeah, exactly. What's the purpose of this? This egg thing? This is to create a water vapor surrounding the environment so that light scatters out. - The same thing, like-- - Oh, so you can sort of see a little bit. - Makes sense. - Yeah, so this is how the system works. - Turn it on. - All right, let's go do the "experimon." How long did it take you to learn to use this? Uh, maybe a few months to get used-- - A few months to get used to it. - Yeah. Because it's a really complicated system. It's really complicated, is it? I hadn't noticed. ( both muttering ) Okay, so this is the chaotic cavity at 100 billion frames a second. Just like nothing. Gav: Once again, the duration of this video is-- you can't even get your head around how short an amount of time it is. Dan: That is amazing. Gav: When we were in the room, it looked like the whole thing was glowing, but now we can see the individual pulse of light bouncing around this thing. Looks like a weird version of "Pong." This is one femtosecond of laser pulse, so it's as if you just went like... - with a laser. - A femtosecond pulse. Gav: And if you pause it, you can see it's just a dot of light. Dan: And it's comped in the shape of the mirrors. I wonder if you could actually build, like, a big maze to get it around. Do, like, a little maze and try to get it in. - World's fastest maze completion. - Yeah. - ( trills ) - Light. Dan: Oh, it almost went in the corner there. Gav: It is. It's like the DVD screensaver, isn't it? You just want it to go straight in the corner. Dan: Nearly. - So this one's 100 billion? - Yeah. Should we see what 500 billion looks like? - All right, so the area is quite small. - Yes. So there's no way that we can stand in and be filmed by this camera. But alternative solution-- little mini-figurines of us. Wait, why is mine-- oh, for goodness sake. - Again, every time. - So we'll put them on there. - Flipping heck. - All right. So, in this experiment, instead of shooting light from the side, I've changed the beam path to bounce back this mirror, this mirror, and use a concave lens to expand the beam to shoot at an angle. So this is more about scattering light on the surface of the figurines? Yes, you're sweeping across the surface of the figures. Because we're obviously not see-through, so... Yeah. This is the static image of the two figures. Now I'm doing 500 billion frames a second with two by two coding. So two by two and a casual half trill. - ( both laugh ) - Peng: Yeah. I think we're pretty much done with this one. This is 500 billion frames a second of our little figurines, with a resolution of 549 by 439. The footage is played back at 20 frames a second, therefore it's slowed down by a factor of 25 billion times. I do like that I was able to successfully photobomb this picture. Dan: I like how it shows up on your nose so much. Gav: All right, I knew you'd say something about that. It does-- it does get caught by my nose, doesn't it? - Dan: Yeah. - Gav: It is interesting to see the light scatter on the surface of something as opposed to go through our body. Dan: So again, all they've done here is pretty much comp in our bodies with the light. So the camera would have got this blue light and they've just taken a picture and comped in us and matched it up to where the light hit. Gav: You look miserable in that. Dan: You look like I've just said something awkward, and you're like, "Ooh." - Should we do these poses? - Yeah, sure. Gav: And you can see on the time scale it's a much slower progression of picoseconds. as opposed to half a trillion frames a second. All right, that's 500 billion done. - Child's play. - Child's play. - Let's crank it up. - All the way? - Yep. - All right. Let's do 10 trillion frames a second. So, Peng, we're at a different camera now. - Is that correct? - Yeah. And this one can do up to 10 trillion frames a second? Yeah, yeah. This is the 10 trillion frames a second. That's the maximum speed that we can do. Here we have a sample which contains diluted milk, about a few millimeters long. That's all that the camera's looking at, is a few millimeters long? Yeah, that's how long the light propagates within 30 picoseconds. Dan: Okay, wow. Here is the same software that we use to capture the image. So for this one we're allowed to keep the lights on? Because we are doing ultra fast images within a very narrow time scale there's a minimum amount of light that comes through the ambient light. - In comparison to the powerful laser. - Laser, yeah. - It's all relative, I suppose. - Yeah, much brighter. - All right, cool. - Yeah, this is how it works. Dan: So this is a much smaller scale 'cause we're using a higher frame rate capturing a very much smaller amount of space and time, essentially. - Yes. - Gav: All right. This is the light traveling through the milk vial at 10 trillion frames a second. - This is the reason we came here. - Yeah. - Gav: So cool. - So on the bottle video, the light seemed to have gained the same speed. But then you gotta remember that the scale of this is much smaller. So this is one millimeter, it says here, is the distance, whereas before, it was an entire bottle. Which shows you that we're actually recording light traveling through such a small amount of space. Gav: And it's so slow now that our picosecond has a decimal place to the hundredth femtosecond. Dan: That's blowing my mind for a start. Gav: When Peng turned on the laser, I didn't see anything at all. But now we can actually see how it moves. On this scale of time, if we fired a bullet through this frame, it would take years to go from one side to the other. Dan: And the light is just going, blip. That really puts it into perspective as well, doesn't it? I just feel like no human should ever have seen this. It's like looking at the base of the universe. I've heard that in the future, the CalTech team actually intends to increase the speed up to one quadrillion frames per second. It's a bit mind-blowing, to be honest. Gav: We have to leave now and go back to our old measly hundreds of thousands of frames a second. Measly, pathetic hundreds of thousands. Thank you very much, Peng, for showing us your amazing kit. - Thank you. - Yeah, thanks. - Thank you. - Learned a lot. Yeah. Well, to me, that's some of the most mind-blowing footage ever. I mean, visually, it's just a blob going from left to right. But to know that that's light-- Dan: I would say it was actually one of the most mind-blowing things that we've seen. Well, I feel very accomplished. Hopefully, you enjoyed watching light move through the air in slow-mo. Feel free to check out other episodes from "Planet Slow Mo," and join us in part two, where we'll be learning a lot more about how this camera works. You can subscribe, too, if you want. We'd appreciate it. Still not sure I'll be able to understand it after part two. - We'll do our best. - All right.

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Channel: The Slow Mo Guys

Views: 28,070,834

Rating: 4.837007 out of 5

Keywords: Slo Mo, Slow Mo, Slomo, Slomow, Slowmow, Planet Slowmo

Id: 7Ys_yKGNFRQ

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Length: 13min 6sec (786 seconds)

Published: Wed Mar 27 2019