Visualizing the Speed of Light and Speed of Sound
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- Опубликовано: 7 дек 2020
- In this animation we will compare the speed of light (the images of objects that reach our eyes) to the speed of sound. We will also look at some everyday examples of where the discrepancy between these two speeds are visible. I hope this video gives you a great understanding of the two speeds. Thanks for watching and please consider subscribing for more!!
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Note:
Speed of sound is based on observations in dry air at 20°C
Speed of light is based on observations in vacuum
Distances between earth, sun and the moon vary throughout the year.
The size and distance of the planets are to scale
Edit: Speed of sound would take ~18,678 minutes to get from earth to the moon. Around 13 days.
In Paris actually sound is faster than light, you will hear the horn of the car behind you before the light turns green
Very good.....
Also in Buenos Aires!
Also in NYC
Not really. Speed of light is constant whereever you are. Thats just people being impatient and honking before it turns green
@@Jibrail5726the joke went over your head
You can tell the speed of light is much faster than the speed of sound. Some people appear bright until you hear them talk.
I love that
nice!
HAAAAAAAAAAAAAA
😂 😂 😂
Lmao, didn't expect that turn
One of my favorite examples is hearing fireworks. I find it so interesting how you can be a couple hundred feet away from a firework and you still notice a delay between the explosion and the sound.
yea really "interesting"........Why do I have to share this world with sheeps....
@@IIISentorIII what a smart and thorough thought through answer.
@@IIISentorIIIstfu man, let the guy enjoy his fireworks
@@IIISentorIIIhaha loser 😂
@@garegos7184how's it smart lol, the speed of sound is an extremely basic concept and observation
One of my favourite examples is when you go to watch a live band in a large venue, and you're sitting in one of the upper levels of the venue, and you look down at the people jumping in the mosh pit. There's always a noticeable 'wave' effect as the people are jumping and the ones near the stage hear the sound before the people further away from the stage.
Good job on the video. But I'm surprised, that there is no mention of the thunderstorm. I think that's the situation most people experiense the difference in the speed of light and sound.
Yes, my teacher taught me this by telling us how to calculate distance to the lightning strike
Very good examples for a young USA audience I'm assuming.
That's the fact most people know since pre-school including yourself so why repeat the obvious
@@sicfxmusic I thought the same
I thought of fireworks
The amazing thing is, that on astronomical scales, even light is slow.
Takes light 44 mins on avg to reach Earth when reflected off Jupiter.... In the long run its all technically slow. But compared to our lives its fast.
Not slow...
Rather
You should say
Extremely slow
yep. over 2.5 million years just to reach one of closest neighboring galaxies, the andromeda
@@nothingspecial9370 glacially slow
"The speed of light is nearly instantaneous...."
[Nonspecific generalisation = instantly irritated].
1:14 Remember, the speed of sound is not always the same, it varies greatly with temperature and slightly with humidity and air pressure. On a chilly winter morning, which is about 14°F (-10°C), sound will only travel about 325 meters per second, +/- 1 meter per second depending on other factors. But on a hot summer day, which is about 95°F (35°C), sound will travel about 352 meters per second, +/- 2 meters per second depending on other factors.
The speed of light also changes depending on factors
nice ctrl v dud
@@mattd6085 not noticeable to humans though
@@Lhaj3 the speed of light varies by the medium it travels through. How it does that is irrelevant
@@mattd6085 no the speed of light is constant. The velocity of light may vary depending on density of medium.
I learnt this as a kid when I saw soccer players play in the park from a distance. Sometimes when they kicked really hard you could hear the thump from far away. I could see the delay between the visible kick and the thump. Kindof like an apple falling on your head moment.
Just think how fast the speed of light is and how far light can travel continuously for a year. Now imagine traveling at the speed of light for decades and we’d barely be able to explore a portion of our galaxy. It’s just mind blowing how incomprehensibly large this universe is.
eyy
Wenoma
even just from the moon and back the speed of light is slow. just in our our solar system it becomes unbearably slow. its sad just how slow the speed limit of the universe really is
*for decades* time dilation enters into the scene
But Earth is flat, and stars are painted on the sky dome
The best example I've heard: If you were sitting in the outfield upper-deck stands at a baseball stadium, and you were also watching the same game's live telecast on a portable television, you would hear the crack of the bat on the television before you heard it from where you were sitting. Meaning the broadcast signal left the stadium, got processed and converted into a signal that was then beamed to an orbiting satellite...then back down to a transmitting tower, and then to the screen and speaker in your tv...all before the sound from the bat reached you from five hundred feet.
also when people clap on the far side of the stadium u see the clapping b4 u hear the sound.
Also, even though it's called a wave, when it happens in the stadium, it's not a tidal interaction with the moon. I love science
Great example and description. You took a normal example like comparing the sound and light traveling from the bat to your seat...and juiced it up on steroids. Appropriate for a baseball analogy 😂
I hate to be a dick, but there is typically a lot of delay in the processing and converting stage of the broadcast which would cause a few seconds of delay. However, if you ignore them and just go based on the distance light takes to get to your tv than your example still holds.
Also why optical wires use the concept of light to transmit signals.
Props to you actually animating a bullet correctly (separates from casing) and specifying caliber (massive velocity differences) of such a bullet. Can't tell you how many people mess this up while trying to look smart and throw out numbers. Credibility went way up for me to see you do the actual research and math.
This is an excellent animation man
Thanks a lot! Thanks for watching!
2:51 this feels so real. Shows how important sound design is for movies/games/etc.
I feel kinda disappointed when a movie shows an explosion from far away but the sound comes at the same time
@@LnmHive Chernobyl did a good job getting this right
@@OblivionFalls Not great, not terrible
@@OblivionFalls Wow, OblivionFall? I wasn't expecting to see you here, I know of your work with DAGames
This feels like buggy audio latency actually.
For me lightning and thunder are the perfect examples to illustrate this point. One funny aspect of this difference is related to sheppards and the dogs that obey their command by hearing different kinds of whistles. When the distance becomes really great, the sheppards have to keep in mind that the dogs will hear the sound of the whistling with a delay, so the human has to predict the movement of the sheep herd ahead of time, keeping in mind the sound of the whistle will be received by the dog with a delay of two or more seconds, and this involves a lot of knowlege, experience, and technique beyond the traditional herding!
not every one experiences lightning. more people in the world experience a plane flying above them at great heights, so its an easier analogy for the majority to relate and understand. not thunderstorms where most don’t see such a thing.
@@PlayboyKeon Is this true where u live? Is it that rare to watch a thunder? In my country i wouldn’t be exaggerating if i stated that everyone has seen a thunder. They are extremely common.
@@PlayboyKeon I would say much more people in the world experience lighting than a plane flying over there heads lol. You gotta think of all the rual areas of the world with no nearby airports.
I remember when I was a kid, I thought lightning and thunder were two different things... that both happened during storms. After a while, you figure it out.
@@PlayboyKeon Only people that don't experience lightning are blind people.
A real-life example that fascinated me as a child, and whereupon my father explained to me the difference between the speed of sound and the speed of light: I was sitting outside our front door watching some kids playing soccer on the playground across the street when I noticed that the impact of the ball on the grass and the sound of it were out of sync. I remember to this day - almost 30 years later my father's explanation. A true childhood moment.
This is the first Chanel I instantly sign to after finish watching the video. Great job!
Props to the camera man who went all the way from earth to the sun and back.
@@juan2049 this is internet it doesnt fucking matter, try something raw like "the bass came harder than my grandma falling on the stairs" you can complaint that
@@juan2049 your reply isn't original. Come up with new material
@@tuxtitan780 Your reply to the reply isn't original. Come up with new material
@@Cr3reeper "you can complaint that".
Yeah na, with your obviously low I.Q., you have no place telling someone what they can say or not.
@@259 Your reply to the reply to the reply isn't original. Come up with new material
I was looking for such a video 2 years ago!
Glad you found it!!
What a fabulous representation!
Thank you for the great learning tools
The most mind-blowing thing to me is that in cosmic terms, even light is slow. That's why we must go right to LUDICROUS SPEED if we want to to actually explore the universe.
HAHA going plaid.
Nothing can travel faster than the speed of light so get that idea out your head 😂
@BRKS1999 Thanks Mr. Scientist!! You are very smart.
Light isn't slow because time is relative. For a photon moving at light speed nor time nor space exist. A photon reaches any point of the universe within the same instant it is created.
So if we were to move close to light speed we could cross the universe, in let's say 2 seconds while for people staying on earth countless billions of years would have passed.
I live close to railroad tracks. I love hearing the Doppler Shift at night because the air is usually quieter and denser, and the effect is so much more distinct. Having the floor in my apartment jiggle like Jell-O because it's a silt river valley is also fun.
Sounds like my cousin Vinny lol do you have a revolver too.
@@ben_mac8670 ur weird
My family has some property adjoining a creek, along which we built a cabin on stilts. It’s probably 1000 feet from an interstate bridge crossing the creek, and when trucks hit the bridge you can feel it shake the whole cabin. The soil is like jello. This is a very large creek too, the bridge is probably over 100 feet long.
What's really weird is to stand on a golf course green and look back at that hole's tee box (c. 100 meters away) and hear the sound of the club hitting the ball AFTER the player has completed his swing. I've heard this many times.
I remember as a kid watching people across a sizeable field beat their rugs and you would watch them swing, hit the rug and get ready for another swing before the initial sound hit you.
One can just be in bleachers at a baseball stadium as I have as a kid, witnessing a full swing of the bat…and the delayed “crack”.
@@Jeesus353 one intuitive kid
The background music is a great choice. Perfect animation documentary
That was fantastic. Well done great vid!
Well explained visually & great animation! 👍
I love how this video isn’t packed with information, it’s a super easy concept that you could’ve explained in 1 minute but instead made a very interesting and comprehensive animation, great job
wow I really appreciated the closing with the example at the court!!
Such a good visualization. Thanks so much!
Underrated channel. Good effort, good explanation, good knowledge. Keep it up.
The comparison between sound through the Golden Gate and light travelling between moon and Earth really makes you grasp the difference between velocities... All you'll ever need
Lovely, informative video!
I thought this was amazing! The entire time I was thinking about a time when I was a kid hiking some mountains with my dad and he stayed back a distance and threw a big rock down to the ground to demonstrate this.
Even though light going around the earth 7,5 times a second seems fast, it is slow enough to cause noticeable delay in communication across the earth. It is impossible to get ping lower than about 140 ms between places in the opposite sides of the earth and in practise it's even more because light in fiber travels slower than in vacuum and you don't have fibers in straight line between every two points on the earth.
Also the light is not travelling straight along the fiber, it is bouncing off the walls in a zig-zag or a spiral. There is also the helix factor - fibers inside the cable are wound around each other similar to the rope but not as steeply of course.
It's also impossible to get less than 140 ping when playing on servers in the same country as you
Don't forget about interconnects. They greatly decrease throughput
you can, by adjusting the ping programe to divide whatever ping it shows by 140.
Light cannot travel at any speed other than light speed. Light in fiber don’t travel slower, they just take longer time because their distance is longer. Light in vacuum will travel straight while light in fiber will be traveling by bouncing in the fiber walls.
I had an interesting experience with the speed of light and sound at the age of 12 (or maybe 13 - it would have been one of two possible years). The casino my dad worked at was putting on a huge fireworks show, and he was able to get us in to see it, but we were watching from indoors, in a building very far away. I don't know exactly how long the delay was (should have counted!) but I remember being struck by just how long it took the sound to reach us after seeing the fireworks. It was at least three or four seconds, probably more. Of course I knew even then that light was much faster than sound, but it was very memorable to experience it in such a dramatic and "in-your-face" way.
I had a simmilar experience by watching a man chopping wood at a camp ground. I would see him hit the wood then a second or so later I would hear the chop. It was too much for my 5 year old mind to comprehend.
That’s such a cool experience/introduction to that concept! When you see lightning, the amount of seconds determines how many miles(idk about the practice in metric) away it is. Only until a few years ago was I at home when I saw a massive bright flash of lightning, so I began to count. Before i could barely even get to HALF a second, I heard the thunder. Told my friend that it probably struck a few streets down from us. We went to check once the storm cleared and lightning had struck a tree a few streets over.
@@Timbo360 It takes sound about five seconds to go one mile
@@myofficegoes65 thanks, I forgot what the practice was
you don’t see fireworks too often do ya?
this is applicable to track as well! my school can’t afford very good timing technology so we use stopwatches for things like the 100m dash. we stand at the finish line and the rule of thumb is start the clock when you see the guns smoke, not when you hear the gunshot.
excellent job of showing the two.
Great job! I'm really surprised. This illustrates the difference between knowing and understanding. Because you understand the concepts, you are comfortable "playing" with the elements to show the information through different aspects. I was aware that some 9 mm bullets travel the speed of sound, and that light takes about 8 minutes to travel between the sun and back, but putting all of those in one place to compare 2 completely different speeds is impressive. When Richard Feynman said "Explain to me like I'm a 5-year-old", I think this is what he meant. Plus you used everyday elements like watching a plane or basketball from a distance. I wish you were my teacher growing up.
Thank you! Its interesting you say that! I heard that quote when I started my channel and I only begin to write my script when I'm that familiar with the science! Its truly a clear indication of a deep understanding of the material and I'm very glad I was able to portray that to my viewers! Thanks for watching!
Really well done, especially with the visuals. Thank you!
I subscribed to this channel for 2 reasons:
1) Your animations and explanations are clear and concise.
2) You use metric units in all your measurements, and you don't cause the rest of the world to want to gouge out their eyeballs from sheer frustration by using miles, yards, feet and other incomprehensible primitive imperial gobbledygook. Thank you for moving science forward.
Hahaha yes, I’m Canadian so it’s just more natural for me! Thanks for the very kind comment!
You ignore the simple fact that many of us Brits were educated in the imperial system and on road signs throughout Britain distances are still shown in miles.
That's cuz not enough money to change all the signs and anything in the administration.
A mars Rover nasa failed, way to go with the rover maker miscomm using imperial
Your second reason makes you sound like a jerk tbh
It's videos like this that keep me glued to my chair ( not literally) when I should be doing household chores. ( Now should I have a coffee and watch some more ) 😊
Nice video. One of the best examples are fireworks . You see flash and then hear the sound .
Easier example is to see a lightning bolt then hear it a few seconds latter.
yes, but i think it is over used, & always recited in an almost fixed & repeated sentence, that almost sounds like a clump of words...now that i think about it
@@OmarTheAtheistAziz It's overused because it's a great example that many people can relate to. Reaches audiences far and wide, and is easy to understand, and is true.
Wish more videos were like this. Nice to not have bs.
I love car racing and you can clearly see the difference in those videos recorded by distance from the side of the circuits.
Sometimes the car is visually braking and taking the corner but only a moment after the deceleration sound starts.
The image is clearly ahead of the sound.
As a visual learner, until now I was never actually able to fully appreciate the speed of light, thank you!
Back in the days of broadcast TV before the usage of satellites, a live broadcast of a singer would be heard by people in front of the TV before people in the back of the theater would hear it.
No such thing.
@@lookoutforchris ?
@@lookoutforchris Communist-sympathizing unionized public school teachers have brainwashed the entire population. Everyone wins a trophy.
Impeach the bums!
@@Wmann ruclips.net/video/rhgwIhB58PA/видео.html
This video is pretty dope and its a shame there is only 5.5k views dude. Well done, and I'm sorry. Take a like and a sub as condolences.
Its has over 300k now..one day after you say this, crazy
@@glokdreamz 644k :D
what the hell it has 736k now🤔
I guess a single like/comment on a really old video bumps its relevance. Glad I could help!
Well done animation and explanation!
Stunning clarity.
Absolutely incredible explanation.
You are far too easily impressed.
To be honest, I think much more people (including YOU!) would be able to come up with his explanation than to be able to program such a visualization software….
From your 1.83K subs i started to follow you. Lets come back in 1 years and see how far you go. 😊 ❤️from🇧🇩
Same!
you'd be dissapointed
Really great video.
Very cool video! Thanks for making it.
Dude it’s like the music gripped me and made me want to discover what you were going to say.
Everything about this video was perfect! Even some of your sentences were just so perfect and professional, keep up the good work
1 of the best animations
Brilliant video!!
Great job 👏 keep it up
Thanks!!
I remember my first time experiencing the delay in the speed of sound when I was a little kid. There was a guy using a metal shovel to scoop up crumbled up concrete and gravel. I was far enough away to visibly see the shovel hit the ground before I heard it, and I remember thinking wtf? Blew my little mind!
No it didn't.
@@CadillacDriver ??
@@user-dh8oi2mk4f "it blew my little mind".
Yeah na, no little kid thinks that way about delayed sound.
@@CadillacDriver maybe just you
@@AlwaysOnForever
You are gullible.
Using a bullet to represent the speed of sound has to the most American thing I have seen in a long time.
Fantastic lecture and animations
It has always puzzled me that in all my years of schooling not one person ever remarked to me that the speed of light is pretty much exactly a million times the speed of sound. I think it's a handy rule of thumb.
You've explained more in just 3 minutes than school in hours
Not really they took 3 minutes to say light is fast and sound slow
Why would school take 3 hours to say light goes this fast and sound is this fast? Sounds like major cap
@@TechStuff365 I didn’t mean to say three hours I was talking to the original guy who commented who just said hours… his comment also makes no sense because this isn’t even something that they traditionally teach about in school nor would they spend more than five minutes talking about it…. There’s no reason why they would waste any class time teaching a concept that a 10 year old can understand
"The closest visualization of speed of light is your movement when you hear your mom's car and you didn't unfreeze the meat"
Thanks youtube for recommending this MASTERPIECE
Haha love it! Thank you
Good video. I like the end with the basketball. We would go to concerts at the Forum and sometime we were at the other end with binoculars. Light waves were instantaneous but the sound didn't match what we saw. Good example in the video.
Thanks!! Wow great example!!
One important difference though, is that the speed of sound is different depending on what it’s traveling through. It’s faster through water than through air, for example. On the other hand, the speed of light is a universal constant.
not anymore.
The speed of light is 299 792 458 metres per second in vacuum. You will get a different speeds depending on what medium it passes through.
Swing and a miss there bud
Light moves slower in water too.
I remember seeing this for the first time as a kid watching someone framing a house from a distance. The hammer sound matched up with the top of the hammer stroke instead of the impact.
The basketball bouncing is a great example, last week I was a little far away from a person playing basketball and I noticed the ball had a slight delay
So we can clearly notice that a plane has moved by the time we hear it,
but I wonder how far it has moved by the time we see it.
So I work it out:
Say a plane flies overhead 10000 metres up in the sky, travelling at 250m/s,
and using a speed of sound of 330m/s, so it takes the sound 10000m / 330m/s = 30 seconds to reach you,
by which time the plane has travelled a very noticeable 250m/s * 30s = 7500 metres.
And light at 300'000'000m/s, takes 10000m / 300'000'000 = 0.000033 seconds to reach you,
by which time the plane has travelled a 250m/s * 0.000033s = 0.00833m, or 8mm.
That 8mm is quite small, but not un-imagineable. Remarkable!
It is also worthy of note that the speed ratio of sound to light is close to one million times.
Bro needs to relax man
@@lightningmb3321 no, they do not. This is what smart looks like, which we need
That's interesting. I never did the math because I'm lazy and I always thought that by the time the light reach me, the plane would have travel some micrometer or something in that ballpark. Instead, it's almost 1 centimeter which is quite a lot! So basically, when we look at planes in the sky, we are looking at "ghost images" of planes lagging 1 centimeter behind the real thing.
The thought of light going around the earth 7.5 times a second seems kind of manageable in a way. And one would think we could get close to that speed, yet we can’t. If we could, then a more noticeable time travel would be occurring. All this fuss about getting something to move that fast, is the big hurdle.
Speed of light(particle) is constant.299792458 m / s. That is even if you are walking at a speed of 1 m/s, the speed of light in relation to you won't change. Even if you are travelling at 299792457 m/s, the speed of light in relation to you still won't change.
That is why space and time is relational, the speed of time is constant. This also explains why one couldn't attain light speed, because a particle in lightspeed does not experience time. So no perception exists in lightspeed.
Woah, that's insane!
As an electrician.. I appreciate the screw right side up in the intro.. Thanks man
That was an absolutely fantastic animation, and the music was great as well. I’ll subscribe
Thanks!
0:15 Actually, a better way to experience it is by seeing fireworks go off at a distance and then the delay of hearing them.
That’s absolutely cool info dude
I once saw a fireworks display from more than a mile away, maybe a couple miles. I couldn't imagine a better way to visualize the difference between the speed of love but and the speed of sound. It was surprising to see a large firework then to hear it a couple seconds later.
The speed of light is actually really slow when considering the size of the universe.
@Just for playlists the closest stars are 4.25 light years away. Plus at light speed you get time dilation effects so essentially we could colonize hundreds of light years away without even needing to have children on the way.
From our perspective it seems slow on that scale, but to something actually travelling near the speed of light things are much different. What we're looking at is really the difference in how we experience time compared to those particles, it's more like we're observing the curvature of spacetime than the simple speed of light. If you were on a spaceship at speeds approaching the speed of light you could travel to a distant star in an hour while back on Earth 100 years have passed (just for an arbitrary example)
Imagine a scary universe where the speed of light and sound were opposite. You would have to rely on what you hear way before what you see.
Daredevil: Hold my beer.
This is also why thunder happens after the lightning, and why you can calculate the distance by the delay between the two, or why when watching a fireworks show the sound seems so delayed compared to what you’re seeing
Nice job. Thanks
You can easily see the diference by looking at a storm. You will always see the light of the lightning first then after a while the sound of the thunder.
Shhh let youtubers make their money
Only when the lightning is far away. When the lightning hits a tree in your yard, there is no distinguishable time lag between the flash and the ear splitting house shaking crack. But I do still count when the storm is coming in - about 5 seconds per mile.
It’s wild to me that we are so far away from the sun that it takes 8 gd minutes for its light to get here.
Thank you for this excellent video which is really helpful in explaining the subject matter by visual teaching, much better and easier than other methods to grasp and understand.
Thanks RUclips algorithm for recommending me this video and making me feel all smart before bed time 🛏
For the first light example, even if light were slower you wouldn’t see a delay unless you were the one turning on the switch
Lol I was looking for a comment about that. That’s like closing your eyes and saying fireworks don’t have an audible delay
Yeah, and a few switches in my house do have quite a delay on them, so theres no way of knowing if the delay was the light or the switch as a single observer
I don't really understand why you wouldn't see it unless you were the one turning on the switch
Can you please explain why you wouldn't see a delay? Also, in the video, the example *is* about you being the one turning on the switch.
Speed of light and sound depends on medium in which they are traveling.
This
Great Video, Great Explanation
Great Video. Thx
This is great content!
Light travels faster than sound. This is why some people appear bright until you hear them speak.
LOL
bro stole the 12K comment and got 4 likes
@@daykilling9242 lmao
😂😂😂
Another great example of this is when watching Fireworks, you'll often see the flash of light when it explodes, followed a few seconds later by the sound of the explosion. The further away from the explosion you are - the longer the delay between the flash of light and the sound.
this was amazing
Even if there is someone on the moon shining a laser towards you on the Earth, the laser will hit your eye after 1 second but you can't understand it was 1 second, because all electromagnetic wave like radio signals travels at the same speed. So you need to talk telepathically with the other person to know when he shot the laser l.
While you are somewhat correct this experiment can easily be performed if you set a time when the laser should be fired. One clock on the moon and one clock on earth that are in sync with each other. You could then determine that the photons from the laser arrive on earth 1 second later.
@@blastaa Actually to get a measurement of the speed of light at really high accuracies this would not be optimal given that the displacement of synchronized clocks to get them to their respective (far away) locations would, according to Einstein’s theory of relativity, have them end up slightly desynchronized. In fine, your measurement would have a considerable error. I think the current best method we have is measuring the speed of a laser reflecting off of a mirror (we have in fact placed some on the moon in past missions). You send the laser, knowing perfectly when, thus giving you a good estimation of the speed!
Forget my channel, THIS is an underrated channel!
You get a sub nonetheless
cringe
@@scrubblack Come back when you understand what that word means
@@wowalamoiz9489 still cringe
@@scrubblack Get some friends
In Summary:
Speed of Sound: I'm pretty fast
Speed of Light: *NYYYYOOOOOM*
Kudos to this channel. No "Hi guys, welcome back to my channel" kinda BS just straight knowledge
Kudos to the clever humans that precisely measured the speed of light. Before them, the best estimate for the speed of light was “friggin’ fast”!😉
they used Jupiter's moons to do it.
It always fun for me to remember that light is like the maximum for the universe, even if you had a superpower that allows you to move faster than light you cant even react faster than it because light has the information that your brain processes. You'd still be restricted to lightspeed and below, even with magic scifi powers
Beautiful !
I always noticed the speed of sound at our ski trainings, when you are on the ski lift and you watch someone during slalom training from something between 200 oand 300 meters you can notice such a big delay from touching the slalom gate to hearing it, sometimes the delay is so big that athlete is 2 gates further than the gate from which the sound came from.
Slalom Gates are ideal for this because they are loud and you can be veeery far away.