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2019-04-26
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Not so related but also interesting factoid: the front of a "slow" radio wave actually travels through a vacuum just as fast as the front a light wave. It's just the frequency of the wave that is faster or slower than light. I always thought radio waves actually arrived at their destination later than light waves.
Huh.. I never thought about that.. but yeah it’s electromagnetic radiation so it should go at the same speed as other electromagnetic radiation. :thinking_face:
I had never heard of a radio wave referred to as "slow". Perhaps because the frequency is so much lower than visible light?
Yeah, the fact that they're all the same kind of waves, just at different freqs, had escaped me for a long time. I just figured I'd search up the answer the other day and was pleasantly surprised.
I wonder if you could get higher speed communication with low frequency radio waves just by sending lots of separate new waves in a short time :thinking_face: Anybody know about radio waves and if that's been tried?
Information is carried over radio waves by either altering amplitude or frequency. This is also the difference between A.M (Amplitude Modulation) and F.M (Frequency Modulation) radio. http://www.qrg.northwestern.edu/projects/vss/docs/communications/1-how-is-data-put-on-radio-waves.html
But is the arrival of the wave, regardless of its frequency or amplitude, not a piece of information that we can use?
If I send or don't send a 1 hz wave, 10 times a second, can I convey 10 bits of information?
Here’s a nice illustration how antenna ‘receives’ the ‘waves’ https://upload.wikimedia.org/wikipedia/commons/d/dd/Dipole_receiving_antenna_animation_6_800x394x150ms.gif
If you had several waves on that same frequency it would alter how electrons shift from + to - in the antenna and you’d get just noise.
Would they interfere even if they are sent at 10ths of a second increments apart from each other?
Plus, who cares what the frequency is? I just want to know if a wave is inbound on a given 10th of a second or not. I don't care what it's frequency or amplitude is (in this hypothetical)
As mentioned before, radio waves are just like any other electromagnetic waves. So there’s quite a lot of noise and you need to be “listening” to some particular frequency to make any difference.
Hmmm. I guess, for the wave to push the voltage down the conductor, you'd need an entire wave cycle to complete.
Yeah, and this whole wave thing is actually just a useful abstraction. What there actually happens is best described by quantum mechanics. And I’m just a hobbyist. 🙂
But basically the antenna is receiving all kinds of noise and at the receiver end you need to filter the other bands except the ones you’re listening to. Therefore you cannot be listening to arbitrary waves unless you’re in a very controlled environment.
Yeah, I suppose the detector is detecting the motion of the wave, not the front of the wave.
You can think it like that yes. But actually such a thing as “the front of the wave” doesn’t exist in classical mechanical sense.
Ok we’re going deeper. 🙂 So basically electromagnetic waves carry photons and they are actually discrete chunks.
Or actually we’re entering the QM world here. Photons seem to act as both waves and particles. And that’s where the weird part begins.
Yes. Basically everything that can travel at the speed of light must have no mass. And particles that have no mass are basically photons or gluons.
Seems to me if we could just detect that chunk, without having to care about its frequency, we could get 186000 mps communication that could go across the globe, using a low frequency wave to carry it.
And to add more confusion, when we’re talking about ‘the speed of light’ we’re actually talking about ‘the speed of causality’ traveling through the universe.
Right, so that would also mean that the particles inside atoms rotate no faster than the speed of light as well, right?
Most of the laws of physics are symmetric to time. They don’t actually care which direction time flows
jumping through space in zero time sounds like an automaton, rather than classical mechanics
Yeah in classical mechanics or in general relativity jumps don’t just happen. You can bend space&time to the extremes though.
Yeah there are a few known phenomena where the state of a particle can change “instantly” or the position might seem like it was determined beforehand even though it logically would be impossible.
Hah, interesting "7.83 Hz [is] the frequency at which the wavelength equals the circumference of the Earth" - https://en.wikipedia.org/wiki/Extremely_low_frequency#Schumann_resonances
is this place alive? ive been on 3 diff chan and nothing :(
@rob.rodz.jr9 things might be a little bit async, but low-traffic channels are monitored by some very helpful and kind people — so just ask something and see what happens.
i love kind folks. im in Georgia USA. never really been able to make technology minded friends.
This is definitely the right channel for social chat 🙂 Although as Orestis says, daytime US tends to be the busy hours around here. #beginners is definitely a good one if you're new to Clojure and have questions. Welcome!
very nice :) thx u for the response
new to slack and clojure and front end dev, well pretty much any kind of real dev... im a superuser if u will
Welcome @rob.rodz.jr9 -- you should find daytime US much chattier 🙂
@seancorfield yes and thats real good cuz i cant wait to have live convo with someone like me
id prob look like a kid in a candy store if i was ever attending a conference with a ton of smart people
Conj just got announced for November 21-23 in Durham, NC -- it's always a blast!
i break even weekly man, the struggle is real.... i wish i could do some kind of remote work just to b able to go
@rob.rodz.jr9 There are opportunity grants for Clojure/Conj, maybe you qualify for one? http://2018.clojure-conj.org/opportunity-grants/
@christian.gonzalez gracias for the info