What If Light Was Really Slow? Again.
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- Опубликовано: 14 дек 2023
- I decided to rediscover the world in which light is slow. The implications are much more interesting than I thought.
The relativistic raytracing uses Sebastian Lague's raytracing project as the base. Check it out here: • Coding Adventure: Ray ...
If you are feeling generous:
/ worldsinmotion
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📃Sources & Further Reading:
Sources:
github.com/SebLague/Ray-Tracing
Yurtsever, U., & Wilkinson, S. (2015). Limits and Signatures of Relativistic Spaceflight. ArXiv. /abs/1503.05845 - arxiv.org/abs/1503.05845
file.scirp.org/Html/10-750328...
github.com/MITGameLab/OpenRel...
en.wikipedia.org/wiki/Electro...
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🎵 Music used:
Virtual Roaming Charges - half.cool
Rinse Repeat - DivKid
Icelandic Arpeggios - DivKid
Intellect - Yung Logos
Final Girl - Jeremy Blake
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The way you so nonchalantly say "So I programmed this super-difficult photon path visualizer with a dynamic POV." I'm impressed.
or just modified an existing one.
it's not at all difficult, and it's very poorly implemented compared to what many write as teenagers
@@eigentensor what teenagers?
It really hurts to see such high-quality content get so few views
well clearly it didnt have enough time to grow yet
Yeah, instead of using boring buildings and teapots, he should've used 3d animations of some fat african-american girls doing some twerking or something like that.
be glad you found him early and actually get to communicate with him via the comments.
So few views? 45k is a pretty big number I’d be overwhelmed if that many people watched a video i made (not just a Mario kart clip)
You can share instead of complaining
I never thought that "light shockwaves" were a thing. Mainly because you need a _really_ special approach (and idea) to even got to the point where they are non-instant.
I love these videos ♥
Actually there is real-world video of light bouncing off the PET bottle in the same way. Of course femtosecond lasers were involved.
In the Discworld novels, light travels very slowly, thus sunrises are describe as golden light moving across a landscape like honey. I wonder if you could visualize that with a basic 3D landscape and a sun slowly moving across the sky while also sending out sub-sonic photons.
I actually didn't know that about discworld. I'm reading Guards! Guards! right now and that's a cool fun fact
@@serbianspaceforce6873 You're in for a treat, the Night Watch novels on the discworld are absolutely stellar.
But then again, all of Pratchett's work is fun to read.
The early Rincewind novels have a very different feel compared to the later ones, you can really watch Discworld grow and mature as a setting.
The books featuring the witches are also a blast.
In short, you're in for a treat with every book.
@@h.a.9880Prachett definitely has a very unique writing style and tempo, it's great fun to read.
@@h.a.9880 I've gone through 20+ discworld books, as much as I love the seriies, i'm disappointed in the tonal shift from the first few books to the rest of the seriies, I wish we would havegot 20 rincewind focused books, ala Conan by R.E Howard.
Moving Pictures is probably my favorite discworld book.
@@ai_serf As much as I can understand that feeling, I am very glad that the setting branched out and also added some parodies of a city watch, witches, the post and banking systems... it's a lot of variety.
Personally, I would have prefered a more focused middle-ages fantasy setting rather than tha (at times) almost victorian setting here and there, but it's still very enjoyable to me.
Seeing the light bouncing making shockwaves really changed how I understand Diffuse Lighting, wow, thank you! So cool
Really cool! I implemented a similar ray tracer for my graphics class, and now I don't have to make a video about it
One thing you might try to increase the resolution is to render all of the frames in one big batch, instead of rendering over and over again (which I assume you are doing?)
Vram becomes a problem, Unity kept wanting to crash so I had to stack some shots :)
@@worldsinmotionWhat GPUs do you have? You could buy four V100 SXM2s, an AOM-SXMV, and all the necessary connectors (PCIe ribbons, 2x RSC-G-6) for another 64GB of VRAM and extra computing power. If you have US$1050 and an extra 1000W to spare that is.
@@worldsinmotion Please share how much VRAM you had so we know what to demand for :)
This is fascinating. Those low light room simulations remind me of walking about the house in the dark / at night - my eyes only catching a dull grainy, gray image.
And only out of the edges of your vision since that's where the most light-sensitive(but monochrome) receptors are
@@EliSmithyes, indeed.
I believe that is an artifact of the first moments after the light gets on, eventually the whole room will flood with fotons and you will see the same picture as normally, until spmething moves.
It's gray because there is barely any light so everything is discolored due to lack of input from the eyes
I would really like to see this, but also with photons behaving as if they had newtonian gravity.
Interestingly, light rays are bent by Earth's gravity, but not quite like other objetcs. Photons's trajectories, because they travel at c, are bent twice as much as massive objects, they effectively feel 2g of force near the surface instead of one
There isn't really such a thing that makes sense because light's defining feature is that it travels at the same speed for all observers. Doing this creates something fundamentally different to a photon that follows different laws of physics and completely changes the properties of light itself. Also, @HunsterMonter is correct. To a very good approximation in general relativity, light bends by roughly twice the angle as something obeying Newtonian gravity and approaching at the speed of light.
Controlling light could easily be the most broken power
Yeah and the light fairies in tinkerbell have done NOTHING with it
That channel is CRIMINALLY and ILLEGALLY underrated.
Love that video. Take care bro
This is actually fascinating. Thank you for putting the time into creating this video.
Thank you for making these. This video and your last one on the topic stand unmatched quality and explanation. Your previous one sits at the top of my all time favorite physics videos.
FINALLY I feel like I understand the whole space/time relativity thing. This is a very good way of illustrating it.
Those clips at the end really show how wave-like light appears at these speeds.
Dude amazing video! Really good explainations
love love love this kind of content !!!!
Incredible work. Thank you.
I am so happy right now that i found your channel :)
This video was an amazing thank you. I now kinda wana simulate and play around with this stuff myself
Thanks. This was mind bending and wonderful.
happy new year :)) pls keep making good content
Thanks for bringing back that cool song at the intro ❤❤
Great content. 1000 times better then TV docus nowadays... 😁
I've had this exact thought before and wondered what it looked like and now finally have an answer
The simulated living room environment is similar to my own. I have a flatscreen on top of a credenza with large stereo speakers on the sides of the TV, integrated such that they always provide the sound. No yucky TV speaker noises. My favorite part was at the end when you were showing the light source move around, pretty neat.
Thankful that people like you exist
Looking forward to the sound video. I've been watching a lot of videos about sound diffraction and I'd love if you took a deep dive.
Did you account for the travel time from the last bounce to the camera? Objects closer to the camera should appear faster
interesting.
Beautiful video!
So this is how we would experience light if we were cosmic giants. Love it
Correction on the space vs time diagram example:
The thing that cannot go below zero is the proper time, which can be defined as dT^2=dt^2-dx^2/c^2.
This is the time the moving object experience when moving in your frame of reference a dx distance over a period of time t. The negative sign means the speed of light is when the proper time interval is the lowest it can go without becoming a complex number, also equivalent to light not experiencing time(even though its time component in our coordinate system is non zero).
The example has the right intuition but the math is a bit misleading
The simulations are really nice though. I think there is an old youtube video where they film a pulse of light passing through a water filled cola bottle irl and it looks just like the example with the teapot.
this concept would make a great cave exploration game
Video of the year!
1:17 finally someone explained it in a way I _completely_ get it. Why did no-one mention this before?
Commenting for the algorithm: another great video, keep up the good work :)
Awesome Work!
Hey! Thanks a bunch! Much appreciated :)
Damn this is a cool explanation! This'll get more views in no time 😊
This is pretty cool.
As you say about the video on sound... Have you ever wonder why the sound from a far away lightning stars low in volume and then progressively gets louder instead of starting out really low in the beginning? I always asked myself that but I couldn't get an answer for it. Though I guess it has to do with the bounces in the landscape as the soundwave cross the long distance.
Keep it up until your channel blows up like a supernova!
This (pun intended) illuminated some things about light for me. I especially liked the depiction of the rays bouncing!
Dope vid!
I would REALLY love to see a similar simulation with gravity-affected light
This is way more complicated than it first sounds, unfortunately. It would involve solving the Einstein field equations of general relativity and that's a *very* difficult computational task for almost any physical system except certain special cases. You can't just get away with assuming a Newtonian model of gravity; it would violate light's fundamental property that it travels at the same speed for all observers and it predicts measurably incorrect trajectories of photons in the real world.
This reminds me of that Slow Mo Guys video "Filming the Speed of Light at 10 Trillion FPS" where they used insanely short pulses of laser light to visualise light passing through a scene.
This is awesome 👏
Dude i thought this video would havw line 3mil views. You've gained a subscriber
great video
I'm mulling over the shape of the buildings, and I'm not convinced they would bend away from a moving observer under continuous lighting. Gonna go through a few scenarios
1) The observer is stationery, the world is dark, and the building glows for just a moment. Since the light is slow, the observer would see the building's glow rise start at eye level and then spread up and down, but mostly up. Shape clearly not affected. Just the latency of seeing the top of the building. When it reaches the observer, the light from the base is more recent, where the light from the top is older.
2) Observer is moving towards the building, the world is dark, building emits short glow. The glow would spread similarly, but more quickly, as the later light now has less distance to travel, as the observer has moved closer since the beginning of the pulse. So, the last bit of light would still be from the top of the tower, but at an angle of incident for the observer being closer. In other words, the observer would see the base of the building earlier and at a further lateral distance than the top of the building. In this scenario the shape may seem weird if we think of the shape of the pulse, but every part of the pulse shows the angle of the building based on the observer's location.
Okay so 3) Observer is stationery, the world is lit continuously, but super slow. Since the light is continuous, the observer sees all heights of the building but from different times. So at an initial distance from the building, the observer sees the base reflecting 12:00 sunlight, the second story reflecting 10:00 am sunlight, and the top of the building reflecting sunrise. The light and coloring of the building will look wildly different from our world.
Last scenario 4) Same as 3 but observer is moving towards the building. Much like 2 vs 1, while the observed originating light time shifts during movement, the angle of the light observed is still dependent of the position of the observer. So the observer should see a normally shaped building, but their movement changes which time of day the see each height of the building.
Awesome!!
24 subs? You deserve more
Cool got me subed
killer visuals!
You would not, in fact, get a rainbow effect from traveling through the universe close to the speed of light. Most natural light sources, including the CMB, give off a thermal spectrum, not a single frequency, so you'd see "white" light at different color temperatures.
Damn, really cool!
2:00 Star trek and so on are "using" the concept of a warp drive and therefore are not moving through space but moving space itself to achieve faster than light travel
This is incredible. Thank you so much... I hope this gets to the whole world!
Real Eyes
Realize
Real Lies
Nice video
Nice video 👍
what you used to render this, looks AMAZING!!!
Really cool. I know that probably took a lot of processing power, but maybe if you could outsource the rendering to a render farm, it’d be really cool to see that simulated with higher samples, and maybe run through a denoise algorithm.
So amazing
In the next video, he will start talking years after the video started. Because his sound has to reach to the microphone and turn into electrical waves. Then since light speed is slow too, electricity is way slower too. So it will take a lot of time to reach us. Then of course it will be turned into sound again through our speakers. Get ready to watch the video muted a long time before his voice reaches you XD
I'm gonna call that trade off of spatial speed and temporal speed the luminal compass. Magnitude doesn't change, but we can change direction (kinda).
It is a god tier underrated YT
Hey looks like the algorithm has decided this is in fact a good video
3:10 Light is a wave front, and the observed would determine light direction to be othogonal to the fronts, so this part of argument (as such) does not apply. The wave fronts actually do appear tilted due to the shift in simultaneity: waves further ahead are ahead in time. Interestingly the angle is just in accordance to this photon particle explanation.
Brillant!
How does this affect transparent material? Is the index of refraction more extreme? Do total internal reflections happen at a different angle? And would the sun be able to sustain fusion with the lesser energy resulting from the lower speed of light?
I saw your previous video a while back, and both that one and this one are great stuff! I just wanted to let you know (and I know English isn't your native language and that's totally fine) that the word "causality" is pronounced "koz-ael-it-ee", like "cause-ality". It's not like the word "casual" (kaz-yew-all). "Causality" isn't "casuality". Just some constructive feedback, your videos are super awesome! I was just telling my oldest daughter on our way home from her school yesterday how I'd like to do a proper high-speed motion simulation that shows what light would appear like if we could move really fast, because everything I'd seen so far either just distorted space or warped the colors, but didn't seem to capture all of the actual effects that would take place. I think you beat me to it!
Or in British english: "kor-zal-ee-tee"
Also I would have thought the american would be better spelt as "kah-zal-ee-dee" (non american's actually pronounce t's in the middle of the word)
commenting for the algorithm, great video!
Your computer is on a whole nother level
What if light was really fast? I think that'd be cool.
since you said in the teapot part that light can only bounce so many times as it loses energy with each bounce, would that inturn infer as it loses energy it will change wavelength and inturn change color
A follow up yay 🎉
Fantastic
How about showing the photon trajectories from less distance or bounces to more? I think it would show beautiful and smooth shapes
it really looks like scanner in the end or some echolocation visualization.
Yea
Changing the speed of light is literally like trying to modify the code that already works, only to find out that everything broke and now you have millions of errors and a ton of bugs that's hard to catch
Imagine how cool that would be implemented in Cycles render engine in Blender and combine it with Open Image Denoise to get rid of the noise. Those are free and open source btw, so that's not impossible at all.
best vid today
yo, incredible.
The rainbow rings are awesome. Sci-fi should get on that
sick!!!!
Single-source sound wave in your video? can I think of it that way?
Now do what if light was soft and fluffy and a dog
"Casuality"? It's Causality.
Thank you. Pet peeve
Clearly it's not his first language, give him a break
Do you think you could make like a really small game out of this?
Even if it's really basic?
What if the light source moved faster than the reduced speed of light? Would the result potentially be similar to what happens with sound in a sonic boom?
Interesting recommendation by the algorithm
One small nitpick - near the beginning, you said “casuality” (like a casual outfit) instead of “causality” (like cause & effect). I’ve run into that issue before too
youtube compression was not kind (this was a reference to how in one scene it went 'youtube compression be kind']
RUclips compression did not like this video
My question is, how can light bounce or reflect? Why is it not absorbed by all materials thus absorbed or canceled out?
I wonder if something actually can travel faster than light. (Ignoring all laws that prevent it, of course.)
What would that look like?
Due to time dilation if you could get close enough to c, it would be able to look like that.
Breaking causality is, like, kinda my bag, baby 😎💯
what program are you using for these renders?
Strikingly similar to coming out of a ketamine trip.
at 1:42 are you saying can or can't travel?
edit: alright i rewatched it and understand now, the answer is can't, nice video btw
Can you reinterpret "changing the speed of light" as "scaling the size and distances between objects" without fucking up gravity, etc or does the physics not behave that way?
Bonus question: if not that is there any way to scale distances, mass, etc such that it's equivelent to our desired behavior, ie light being slowed down without it's trajectory affected