It's a very good video, however I think there is a mixup between the relativistic Doppler effect (due to different velocities) and the cosmological redshift (due to the expansion of the universe). In what regards the expansion of the universe I would tend to argue that it's fine to say the expansion of space is what stretches the wavelength of light. It is not really the same effect as the Doppler effect. In fact, many far away galaxies move away from us faster than the speed of light (or, more rigorously, their distance increases faster than the speed of light), which wouldn't make sense in the Doppler effect formulas (the Lorentz factor is only defined for v The main difference is that the Doppler effect's formula only works locally, or in a flat spacetime, whereas the cosmological redshift only works for comobile objects (objects motionless relative to the expanding space). To have a full description one needs to combine the two. Mathematically, the cosmological redshift is only described by the ratio of the expansion factor of space between the times of reception and emission. The relative distance between the two objects, or their apparent relative speed (which is not a true comobile speed) doesn't come into play in the calculation. Only the factor of how much has the expansion stretched space between emission and reception. If you imagine that a galaxy "moving away from us" due to the expansion of the universe emits a light ray, but that before it reaches us space starts contracting back to its initial size, we will receive the light with exactly the same frequency as it had when emitted. Even though the galaxy was "moving away from us" when it emitted it, it was not a true motion, only an apparent one due to the expansion of the universe, and hence it did not produce any Doppler effect. At the beginning of the video it is stated that energy must be conserved, but in what regards the cosmological redshift I think it is precisely because the expansion of the universe breaks the law of energy conservation that the effect exists. Because the expansion is not time symmetric, Noether's theorem states that the energy of light is not conserved over time, which is why it is measured to have different values over time (regardless of where it was emitted or received).

@ButWhySci

2 жыл бұрын

Oh wow, thanks for expounding on that. It does seem that I have Dunning-Kruger’d myself. Noethers Theorem is a new concept to me and I wasn’t aware lights energy didn’t require conservation. I think that would be a great topic for a video of yours or if you were up for collaborating something I would do someday. You are definitely more knowledgeable in this field than me.

@ScienceClicEN

2 жыл бұрын

@@ButWhySci No worries, I hope my comment didn't sound too harsh, the video is of good quality I just thought it was important to point out the difference

@ButWhySci

2 жыл бұрын

@@ScienceClicEN No not at all. I appreciate it. Astrophysics is not my field of research so I’m not super knowledgeable of all relevant theories. Thanks for letting me know. Would you be opposed to be sending you scripts some months down the road when I return to astrophysics concepts?

@ScienceClicEN

2 жыл бұрын

@@ButWhySci Of course not I would be glad to help don't hesitate!

@constantineconomides1170

2 жыл бұрын

From two channels which I both enjoy tremendously, this small conversation is wonderful to see! Wish you both the best for the future

Your great channel should expand like the universe

@matsgranqvist9928

2 жыл бұрын

So... Away from everything?

@charlesg7926

2 жыл бұрын

I know, I love this channel. Such high IQ concepts explained so brilliantly and simply

@oviya1317

2 жыл бұрын

No away ...just towards everything. Change ur frame of reference

@shubhamchandra5417

2 жыл бұрын

This chat must go on

@dhedarkhcustard

13 күн бұрын

This is the best comment I've seen on a KZread video all year.

Cannot believe how few views these amazing videos have. Someday you'll hit the algorithm and make bank

I really don't get why you don't have more views. This is so high quality and interesting, plus you already have a viral video with almost 500k views. Anyway hope you keep doing what you're doing because it's really something great. Best of luck man! :D

@filipjanko4334

2 жыл бұрын

agreed.. one of the most underratted science channels. I quess its the short format of most of his videos, which is sad but also nothing unexpected from YT algo...

@frankdimeglio8216

2 жыл бұрын

@@filipjanko4334 TIME DILATION ultimately proves ON BALANCE that E=MC2 IS F=ma, AS ELECTROMAGNETISM/energy is gravity. News flash ! Gravity IS ELECTROMAGNETISM/energy, AS E=MC2 IS F=MA. The Earth (A PLANET) is a MIDDLE DISTANCE form that is in BALANCED relation to the Sun AND the speed of light (c), AS the stars AND PLANETS are POINTS in the night sky; AS E=mc2 IS F=ma. TIME is NECESSARILY possible/potential AND actual IN BALANCE, AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/ENERGY IS GRAVITY !!! By Frank DiMeglio

Discovered your channel this weekend, amazing work! Really appreciate it, cheers from Brazil!

Outstanding video production and you explained the topic in an engaging and interesting manner. Your narration is outstanding ....with the exception of your periodic "sighs" which makes viewer think you're getting exasperated. Really well done!

Love the way you explain things! Makes so much more sense to me

Keep up, great work. By far my favourite yt channel on science and I stumbled upon many of them

@ButWhySci

3 жыл бұрын

Thanks for the support. I enjoy it making em.

You're channel becoming one of my favourite and I think it's one of the best popular science channel on youtube.

Hello from Canada - Terrific graphics support in the narrative!

Really underrated Channel

Thanks for the video-I now can understand the Doppler-Fizeau effect that I was reading about.

Your video are great and very clear to understand! I just wanted to say that try to put reference or source in description in case viewers want to read that....

This channel is criminally underrated

I love this content man. Found this channel today ! .

I really appreciate your work!

I have watched your many of your videos today. I believe your channel deserve much more than current subscribers. I just subscribed now and I believe that you will hill 10 million or more within 6 months of this comment, you truely deserve that.

Great video. Nice and succinct explanation of concepts that are easy to understand.

You are a great learner and a teacher.

I wish I could be a teacher like this with so much indepth and no cram part

Really best channel for explaining science

dude your videos are amazing

Question! Say you have a gamma ray burst 6 billion light years away. Would that light not redshift down into a less energized form of itself. For instance, can a gamma ray red shift down into an x-ray? If so, would that gamma ray burst that occured 6 billion light years away be red shifted into x ray (or lower) by the time it reached us?

I love love love your videos, I can't believe I haven't dropped by before! May I ask, what do you use to do your equations at 5:26? That would be so useful in class to show a derivation!!! Edit: Looked through some more comments, and I see you use Blender? In which case I am so impressed but also slightly depressed because I could never do the same. Incredible effect though, really makes the steps of the problem visual!

At 8:10 check the formula please. Momentum should be Planck's Constant divided by wavelength. Anyhow from difference in timings of two successive crests impacting the wall at rest and in motion has really clarified the reason behind shifting of wavelength of light.

@ButWhySci

3 жыл бұрын

oops yea you're correct. Must have been on autopilot when I did that.

You are just awsome , carry on

Great work thanks dude

@ 4:55 you have a wall moving away from a wave front - why? Is the light travelling at c - v? And then you have the freq changing gradually through space? Is it a gradual change between source and detector or is it all taking place at the detector (wall)?

Amazing content

This video should be huge

Great video.

This channel will grow fast 😇

great explanation man.. totally loved it.. By the way,, great animations.. which software do you use to make those animations..?

@iaimboti

2 жыл бұрын

he said blender in a reply to someone else who asked this question. which makes sense since it is a free and powerful tool.

Could this be described in terms of the light's covector intersecting earth's velocity tangent to a hyperbolic worldline for accelerated frames? Something about Rindler horizons?

Very well explained! Thanks! I still wonder how the speed of light is always measured as 3*10^8 m/s in every reference system. Consider if you (person A) are chasing a photon having a difference in speed of only 1 m/s measured by someone else (person B) outside your reference system. You (A) would still MEASURE 3*10^8 m/s as the speed of the light right? But compared to another person (B) outside of your reference system, will they measure a 1 m/s difference if they measure your speed to be (c - 1m/s)? I imagine your MEASUREMENT of the speed of light, which is 1 m/s for person B, becomes 3*10^8 m/s because of length contraction. Is this correct?

Can you do a video on how speed of light is actually speed of spacetime updates which happens to be the limit massless objects approach?

so its the same redshifting one would experience from gravitational time dilation of light coming from our sun to earth?

Omg you actually answered my question 😭

I suggest the red shift seen from distant light is not caused by expansion, but rather by the mass a light wave encounters on its journey to your red shift measuring device. Just as a buoy in the ocean stretches a wave that encounters it as the wave accommodates the energy released as it travels around the buoy, the light wave stretches around any mass it encounters and accommodates the loss of energy as it moves past the mass encountered. There is no way of knowing how many mass encounters a light wave has had as it travels to your red shift measuring device, only that light from very distant sources must encounter more obstacles of mass during its journey.

So light doesn't always travel the same speed relative to us, we just make up time dilation so that it looks the same in all reference frames.

It has now been postulated that the galactic "red shift" we are used to seeing and hearing about may in fact be an observational "mirage". This new hypothesis also solves the current mystery-problems of dark energy, dark matter and the "expansion" of space-time. It is based on the premise that the "mass" of sub-atomic particles were ever-changing during the early epoch of the Universe.

So if I and my friend stood in just a metre apart, we also move away from each other but very tiny distance?

bawal h bhai!!!!

The attempt to address the "why" of red shift was pretty good but a little Hand Wavy at the end; I get the impression that the maker sensed that something is still missing from the explanation he gave.

That was such a good video, I hope I couldve understood it though, my background is turning out to not be enough

3:05 Damn that worm is vibin

probably a stupid question but do the waves exist regardless of how wavy they are, only pushing a photon along its length like strumming a guitar, using the thing the wave uses to be a wave? like reality is an infinitely complex knot that connects with all points of the universe, photons only moving from one place to the next by exciting the "strings".

8:08 is the formula actually h=p x λ?

From where do you learn this amazing animating? I also wanna learn it... Please reply

@ButWhySci

3 жыл бұрын

It's a free program called Blender.

Can you name any sources? This video is quite relevant for my school work and my teachers consider sources as inevitable

Good vid 🫡

This was exactly what i was looking for. I got confused bcs it makes no sense for an object to infinitely stretch. I thought "does it eventually decay ? into the quantum field or smt like that ?" This explains that it is not an object and the properties emerge bcs of frames of references + momentum but i am still left wondering how it relates to the quantum field... What are photons even relative to the vacuum of space ? i will need to learn more.

The Rope Hypothesis by Bill Gaede describes light much better than contemporary physics does and solve the duality of light issue.

5:25 Me pretending to understand advanced math: Hmm yes, those are letters and numbers.

I fucking LOVE your channel thank you so much

3:40-3:50 ive watched literally dozens of light wave animations. they all inaccurately depict a light wave moving in 2 dimensions. this is the FIRST animation Ive seen where it correctly moves in 3 dimensions as a spiral moving forward.

The doppler effect requires a medium to distort the sound. Relativity has no medium

So how does red shift work relate to the 'twins paradox'... maybe red shift has more to do with the nature of light... maybe dark energy is more about the nature of gravity...

C really needs to be re framed as h/s. This eliminates an arbitrary and folds it back on a?constant. Especially regarding photons this means that every photon has the same number of Planck involved. Whether they are in energy axis or time axis. If quanta are discrete shouldn't our model be?

At 8:09, the equation should be p= h/(lambda)

8:34 Now cosmological redshirt Is more keen with gravity light shift

Two things I need and one I don't; pen, paper and hangover respectively.

The Hubble shift is explained also with an Einstein Dicke cosmology.

At the end you say light had time to accelerate? Can it??? You say wavelength is not a real property of light. Confused.

@ButWhySci

3 жыл бұрын

First, 'it' refers to earth. So earth has time to accelerate from the original frame of reference the light was emitted from. Second, light doesn't have a physical wavelength. We use wavelength to describe its energy but it's not something it actually possess.

@rosie_band

3 жыл бұрын

@@ButWhySci so difficult. Water waves have water as medium. Light waves have no medium? I listen to FM radio on a wave length and light is also electromagn. Radiation. But light has no wave length. It had no mass but it has a force so we can use a solar sail. It is a wave but also a photon. 😣😣🤔🤔🤔😑😑😶

@joepierson3859

2 жыл бұрын

@@rosie_band light is neither a wave or a particle it's a complex entity that has particle like qualities and wave like qualities, but it is neither

m=E/c^2. Mass is energy in orbit at c

I understand everything in this video!! 😐

I seriously need to learn more math 😅

To think that we're the ones seeing these colors and that there's a broader spectrum that we can never see.

time does actually slow or speed up.

I almost thought that was my rocket 😁

Came here to subcribe than I realise I alredy did

I don't understand how Doppler effect is possible at all in Einstein relativity for light. Light travels at the same speed in all direction for an observer. So if he pulses light in a circle that circle should spread out evenly for him. I.e. he would be perfectly in a center of those circles, because for any time T any part of that circle would move the same distance away from him. There is also time dilation effect that would change the frequencies of pulses if observed from another observer, but the only thing that matter is relative speed, not the direction of that speed. I.e. if something moves away from us or to us at some speed V then that would cause the same time dilation for that object, thus the frequency of his pulses should be the same regardless if his moves away from you or if he moves towards you, as long as the speed is the same.

@rossbeesley2575

2 жыл бұрын

i was confused by the concept that light travels away from a source at a constant speed regardless of the source’s velocity. how does the light know its reference frame to remain constant?

@randommcranderson5155

2 жыл бұрын

@@rossbeesley2575 light has no mass and is moving at the speed of light, it experiences no time and has no reference frame. According to Einstein, light always moves at c.

It's funny how everyone confuses gravity with cosmological redshift..

This "Red Shift is a bit confusing, as we are measuring the past yes? And the degree of past is variable to the distance, so we are measuring where things WERE thousands, millions, and billions of years ago. So how do we know we are not measuring how fast space WAS expanding? Is it possible that space (whatever that is) WAS expanding ever faster, the further back in time we perceive? After all, if the impossible happened, and a galaxy 10 billion light years away reversed its motion towards us, we would not know that happened for about 10 billion years. And when we map these vast thousands, millions and billions of light years distant galaxies and galaxy clusters, in order to know where they are NOW we would have to know what there motion was over the past thousands , millions and billions of years, as well as know how said space was expanding during that variable time, and this would completely change the map. In ten billion years a galaxy, a galaxy cluster and a super cluster, and variable space expansion, can move stuff a long way.

Too involved. Red shift is caused by gravity; as the photon leaves the star or galaxy, as the photon travels near and through gravitational geodesics AND as the photon travels through space-time, the aether. The aether presses back on the photon preventing it from traveling faster than "C" and also causes the photon to lose energy through a change in wavelength towards the red.

The earth approaches the released object because all motion is relative.

It doesnt. Thats why Pound and Rebka needed a bag of HELIUM to shift the light, cause gravity and relativity didnt shift anything. Only refraction from helium and air did, due to the change in the speed of light which alters the wavelength according to the equation f=v/lambda. So when v increases then lambda also increases and you get a redshift (frequency f does not change during refraction)

No energy, charge, photons or waves etc.

please add subtitel english to all video

It's very tough job to teach physics 😣

Should be horrible to be a foton, never experience the time but at the same time suffer from its effects

why do i get the feeling this guy is more confused than i am?

I still don’t think I fully understand

I don't understand:'D

Uh, space can't actually expand, unless it's a thing, and if it's a thing then aether theory is plausible.

How can particle have a weavelenght ??? Doesnt the light dopler efect just the space betwean particles? And since you are measure it shudnt it be imposible to act as weave? Now im expect many people who dont even understand the question to respond so come will be fun Ps: 20 points for every USATARD who atack me a FOREGINER for not speaking english propherly.... haha

IT IS NOT DOPPLER SHIFT, why do people keep saying that? Doppler shift is the relative motion of the observer to the source, the light DOES NOT CHANGE as it moves through space, it does not 'bunch up' in front of the source. The light does not change at all, but the relative velocity of the observer (and direction of the source), means that the length of time the observer interacts with the photon or wave changes. The wave/photon DOES NOT CHANGE. Doppler shift does not shift the frequency of light/sound as it propagates through space! NO RELATIVE MOTION, with the universe expansion, THERE IS NO RELATIVE MOTION, distant objects are NOT MOVING AWAY FROM YOU! This will confuse you, but it is the length of space that is increasing (if the universe is expanding), that means that the number of kilometers between objects does not change. Say it is 3000 miles between NY and LA (in America), and the earth expanded by 10% instantly, it would still be 3000 miles between NY and LA, and there would be ZERO relative motion. The distance remains the same, the speed of light remains the same (and stays constant), if you were in a car driving at 100mph when the earth expanded, you would still be doing 100mph and you would notice no different. If relative terms you are going faster (by 10%) and you were before, but you are still going the same distance over time. (because space has expanded so has time (spacetime), that is why c is constant, and your 100mph is constant. In the old FLRW Metric for the big bang, this is explained as 'comoving space' but it is NOT, I repeat NOT Doppler shift. Why do physics and cosmologists continue to attribute the redshift with distance observation to Doppler shift, when it is clearly not Doppler shift and is not even how Doppler shift works. In the expanding universe model, when you would see with expanding space between two objects is a great travel time of the light. The light leaves the distant objects at the speed of light regardless of any relative velocity between the distant object and the observer. All that would do is delay the arrival time of the photon to the observer. So if a distant star emits a photon and in 1 second the space between that star and the observer expands 1 light year, then the next photon will arrive 1 year later than the first one. (Shapiro Delay BTW). YES, we do observe a redshift with distance effect in the universe, it is not a great data fit but it is real, that shift is from GRAVITATIONAL Shift (or called Einstein shift). That effect will give you a both directions general shift of light of distant objects. This is what Hubble considered to explain his observed redshift, at the time it was called 'Di Sitter effect'. I really wish physicists' would not keep telling us that light is a wiggly wave interconnect and that stretches' with expanding space. Light is by it's very definition DECOULED to space and time, it literally has NO reference frame, space is NOT a medium that light interacts with in any way, that is why no matter what you do you cannot detect light in transit, you ONLY detect light with it interacts with matter. Light does not change space in any way (it's not coupled to space) like a ship changes the water it goes through, so you cant detect light in space. This is important to understand, it means that as light has NOTHING to do with space (except how long it takes to go through it), the wavelength of light will not change with expanding space. Light is decoupled with space, space and time do not exist for light, and light does not exist for space and time. A plane flying through the air is coupled to the air, it interacts with the air, it experiences the properties of the air. That plane is decoupled from the bottom of the ocean, as far as the plane is concerned the properties of the bottom of the ocean are meaning less. Just as meaningless as the properties of space, light is decoupled to space. Try to think of a direction that is not up/down, left/right, forward/back or a combination of those? Can you conceive of or imaging another direction that is not a combination of X,Y,Z. It's the same thing for light and space but for light ANY distance, speed or direction is meaningless. Light and space do not interact, Doppler does not change the frequency/wavelength of light, expanding space does not change the frequency/wavelength of light. Doppler shift is the Relative motion of the observe with the source of the light, it is a relative motion effect for the observer and is NOT a distance relationship. Redshift from distance is by Gravitational/Einstein shift and is a function of the size (or relative energy density) of the observer relative to the source. Gravitational shift, if you look down you will see the light from down to be more redshifted, if you look up you will see the light from up to be more blue shifted. This is readily observed and we have to correct GPS satellites for this effect. That means in a homogeneous universe, the further you look in distance the redder the objects appear. This is well understood and easy to model yourself with pen and paper, it gives us the redshift we observe. Doppler shift and Einstein shift are the only two real and tested methods of an observed shift in light, and neither of time have anything to do with the light itself changing in transit. The shifts are about the relative energy states of the observer in relation to the source, Doppler shift is from a relative velocity meaning the observer experiences the photon for a shorter or longer period of time (length of time). And Gravity shift is the relative energy of the observer in relation to the source. Which is a shorter or longer length of space. (and space derived time, spacetime). If you like go to my Red it, RRR spacetime_relativity and we can argue this out and discuss it further.

This is unfortunately wrong in every aspect except the most basic stuff like the ambulance. Cosmic redshift, as they call what is caused by the stretching of space, has NOTHING to do with doppler shift. Points in space do not recede from each other due to the stretching of space since the measuring stick gets longer at the same rate. The space between two objects in space separated by one megaparsec expands at the rate of 70km/s but the objects are still one megaparsec away from each other because the megaparsec gets longer. And so there is no doppler shift between them. I don't adhere to this theory but I think it should be explained correctly if at all.

You can say it's relativity, but you can also say that the "ether" is denser the higher up you come. Now, before anyone starts an argument regarding the ether's existence, remember that it's only a word. In this case I put an equality sign between ether and spacetime. I also put an equality sign between spacetime curvature and ether density gradient. The problem with spacetime is that, in the mind of scientists, it's a "fabric" which can only (well, mostly) only be bent and stretched. The ether on the other hand is, again in the minds of people, more like a liquid or gas. As such there can be currents in it. And where could currents be applicable and explain certain observations? Well, think dark matter.

subscribing? I'm considering marrying you

Doppler applies to sound not light.

@IAmGonnaPutSomeDirtInYourEye1

7 күн бұрын

Did the light tell you that?

So nothing is 100% true.

@Im_Rainrot

4 ай бұрын

There's objective truths, such as the speed of light, and there's relativistic truths, such as the speed of anything else

But light is not a wave.