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@boukman3668

5 ай бұрын

What happens if Im accelerating and reach 60% the speed of light and at the same time an object is accelerating towards me in the opposite direction reaching close to the speed of light. Shouldn't I perceive the incoming object to be moving towards me faster than light? V1 + V2

@silverrahul

5 ай бұрын

@@boukman3668 v1 + V2 is incorrect formula. it is only an approximation . The actual formula is (v1 + v2) / (1 + v1.v2/c^2)

@silverrahul

5 ай бұрын

@@rafaelclp i did not understand your question. elaborate

@rafaelclp

5 ай бұрын

@@silverrahul I made a big mistake in the questions, I will remove my comments above and write the corrected questions here. (Question 1) There are three objects in space in a line: A ------ B ------ myself They are both moving in the opposite direction to myself in that line (so, to the left). Relative to myself, A's speed is 0.5c and B's speed is 0.9c. I start accelerating in the opposite direction these objects are moving (so, I accelerate to the right). At some point, my speed relative to A becomes 0.99c. This means our relative speed increased by 0.49c. If I assume Newtonian physics, my speed relative to B becomes 1.39c. But that can't happen, so it's not a simple addition - which is clear from the equations. What would be my speed relative to B? I'm sure it'd be something between 0.99c and c (exclusive), but it's not intuitive to me... (Question 2) Let's add an observer. A ------ B ------ myself ------------------------------- ------------------------------- ----------- C ---------------- Assume the same initial scenario as above and assume that I'm initially not moving relative to C. What would be my speed relative to C after I accelerated to the point where my speed became 0.99c relative to A? Since A is moving at 0.5c to the left, would C see me moving at 0.49c to the right? That's clearly wrong, so again, this is not a simple addition/subtraction. Even though I (myself) see A moving at 0.99c, C can't see me moving at "just" 0.49c, it must see me moving faster than that. This can be understood through length contraction, but it's hard to visualize.

@DeathwingReborn

4 ай бұрын

Question: What is the time dilation from say a photon of lights perspective coming from the sun? You covered what it would look like as something is moving away but not something coming at you at the speed of light as well as constant acceleration. We say it takes a photon to go from the sun to the earth in ~500 seconds. There is no deceleration to take into account due to the photon hitting earth at the speed of light. Also, without doing more research, does our current speed of light (299,792,458 meteres per second) take into account the solar systems parabolic path through the galaxy as well as the path of the Galaxy's speed in relation to the universe and heaven forbid the universes speed of motion in relation to something else (hyperspace?)? Using the same light bouncing method from the photons perspective coming from the sun it takes a longer path than just a straight line from point A to point B (sun and earth). Does our current defined distance to the sun take into account all of these factors as well or is the Sun closer than we think because we did not take into account its motion relative to us? One more question. Gravity has an effect on the speed of light from what I gather from our current understandings told to me by people a lot smarter than myself. If light can not escape the gravity of a black hole than the speed at which light would be moving in relation to everything else would be skewed due to having to travel a longer distance if not completely halted and pulled back in the opposite direction toward the center of a black hole depending on how a black hole affects a photon. Either way if it is gravitational lensing or straight up decreasing the speed at which a photon moves does that not mean that any gravitational anomaly would have an effect on a photon? Does a photon travel slower in relation to us as it leaves the surface of the sun or for that matter travel a longer distance in the case of gravitational lensing. Then for a lack of better terms reach (100%) speed at the LaGrange point between us and the sun where gravity would be 0 and then pick up speed or travel less distance as it enters the gravitational field of the earth to go again for a lack of better terms (102%) Granted the Earth would not impart as much gravity as the sun or the sun as much as a black hole but gravity is not a constant. Because if this is the case then is the speed of light really a constant on a universal scale in relation to us? Last question: Hopefully I wont lose you here but have you heard Russ Humphries hypothesis on a young world using current physics understandings and different ideas being floated such as hyperspace and such and applying it to biblical text? Here is a link to one of his presentations that is on the laymen's level to attempt to explain his thoughts. If I can take what he put in this video at face value it would be able to explain how light from a galaxy currently described by scientists as 4.2 billion years away to only ~6k years using our current understanding of physics. If you have never heard of him could you watch this video and let me know your thoughts? kzread.info/dash/bejne/nqONp5ZmoLapmMY.html

You are literally expanding the frontiers of us viewers’ knowledge with such concise yet intuitive explanations. You have my utmost respect.

@Mahesh_Shenoy

5 ай бұрын

Wow, awesome to hear that :)

@williamwalker39

5 ай бұрын

@@Mahesh_Shenoy Your are missing the point. The effects of Relativity are just apparent and not real. Relativity is an optical illusion. According to Relativity, two inertial moving observers will see each others space contract and time dilate. This is a complete contradiction and a physical impossibility if the effects are real. Objects and the passage of time can not be both small and large at the same time. The only possible explanation is that the observed effects are an optical illusion. Any theory based on Special Relativity, such as General Relativity, must also have the same problem. Hi my name is Dr William Walker and I am a PhD physicist and have been investigating this topic for 30 years. It has been known since the late 1700s by Simone LaPlace that nearfield Gravity is instantaneous by analyzing the stability of the orbits of the planets about the sun. This is actually predicted by General Relativity by analyzing the propagating fields generated by an oscillating mass. In addition, General Relativity predicts that in the farfield Gravity propagates at the speed of light. The farfield speed of gravity was recently confirmed by LIGO. Recently it has been shown that light behaves in the same way by using Maxwell's equations to analyze the propagating fields generated my an oscillating charge. For more information search: William Walker Superluminal. This was experimentally confirmed by measuring radio waves propagating between 2 antennas and separating the antennas from the nearfield to the farfield, which occurs about 1 wavelength from the source. This behavior of gravity and light occurs not only for the phase and group speed, but also the information speed. This instantaneous nature of light and gravity near the source and been kept from the public and is not commonly known. The reason is that it shows that both Special Relativity and General Relativity are wrong! It can be easily shown that Instantaneous nearfield light yields Galilean Relativity and farfield light yields Einstein Relativity. This is because in the nearfield, gamma=1since c= infinity, and in the farfield, gamma= the Relativistic gamma since c= farfield speed of light. Since time and space are real, they can not depend on the frequency of light used. This is because c=wavelength x frequency, and 1 wavelength = c/frequency defines the nearfield from the farfield. Consequently Relativity is an optical illusion. Objects moving near the speed of light appear to contract in length and time appears to slow down, but it is just what you see using farfield light. Using nearfield light you will see that the object has not contracted and time has not changed. For more information: Search William Walker Relativity. Since General Relativity is based on Special Relativity, General Relativity must also be an optical illusion. Spacetime is flat and gravity must be a propagating field. Researchers have shown that in the weak field limit, which is what we only observe, General Relativity reduces to Gravitoelectromagnetism, which shows gravity can be modeled as 4 Maxwell equations similar in form to those for electromagnetic fields, yielding Electric and Magnetic components of gravity. This theory explains all gravitational effects as well as the instantaneous nearfield and speed of light farfield propagating fields. So gravity is a propagating field that can finally be quantized enabling the unification of gravity and quantum mechanics. The current interpretation if quantum mechanics makes no sense, involving particles that are not real until measured, and in a fuzzy superposition of states. On the other hand, the Pilot Wave interpretation of Quantum Mechanics makes makes much more sense, which says particles are always real with real positions and velocities. The particles also interact with an energetic quantum field that permeates all of space, forming a pilot wave that guides the particle. This simpler explainatiin explains all known quantum phenomena. The only problem is that the Pilot Wave is known to interact instantaneously with the particle and all other particles, and this is completely incompatible with Relativity, but is compatible with Galilean Relativity. So due to the evidence presented here, this is no longer a problem, and elevates the Pilot Interpretation to our best explanation of Quantum Mechanics KZread presentation of above argument: kzread.info/dash/bejne/pZmExqxwpra3prQ.html Paper it is based on: William D. Walker and Dag Stranneby, A New Interpretation of Relativity, 2023: vixra.org/abs/2309.0145

Mahesh you are inspiring young people while at the same time re-educating older folks. Perfect.

@Mahesh_Shenoy

5 ай бұрын

That's super awesome to hear :)

I love the way you are able to use your humor and conversational style to make these advanced topics more understandable and accessible.

Sir, Can you make a video on misconceptions about electricity I tried to understand the transfer of energy in wires from other channels but it was hard and some of those concepts are still quite weak.

@Mahesh_Shenoy

5 ай бұрын

I do have a playlist tagged in my homepage.

@snaatanraina

5 ай бұрын

​@@Mahesh_ShenoySir, I watched all those videos and it helped me a lot, but I had watched Derek Muller's (a PhD physicist) video where he claims that electrons carrying potential energy around a complete conducting loop transferring their energy to the load is all FALSE.He explains that how actually energy is transferred through electromagnetic fields and electricity flowing in one isolated conducting wire can cause electric current in the nearby isolated conducting wire. 1st video where he discusses the main question: kzread.info/dash/bejne/lHx9ysmxkdmffLw.htmlsi=yqd0b_RLQ66aEKq2 2nd video where he performs the real experiment: kzread.info/dash/bejne/oX2TupScfau0lZM.htmlsi=R44c_cECV0L3-t1O I had a hard time understanding these videos. Sir, what are your views on his claim and the videos.

@sravankumarjr

5 ай бұрын

​​@@snaatanraina 1st by Physics asylum and next Veretasium only these two ever did video about ur above statement (poynting vector energy flow) do watch the debate video between derek and electroboom

If you can find a way to show how curved spacetime produces gravity, in an intuitive way, that would be really great.

@Mahesh_Shenoy

5 ай бұрын

Need to learn more general relativity for that. Added to the list, though :)

@phillipjoyce8825

4 ай бұрын

@@Mahesh_Shenoy A great way to visualise that is imagine holding out a bed sheet from all 4 corners, then putting a bowling ball in the middle. The funnel is like curved spacetime due to gravity. Imagine travelling in a straight line and going into the funnel, you either drop into the middle and crash into the bowling ball, or you end up going around and around it indefinitely, or if you go in fast enough, your straight path deviates slightly and then you escape it entirely

@danielblumowski34

4 ай бұрын

​@@phillipjoyce8825No, this doesn't explain anything. When you put a ball on the sheet it creates a dent in which other balls fall. They fall because of gravity, so you are explaining gravity with gravity. As for an actual explanation: spacetime gets distorted around massive objects, but such a curved spacetime can only influence objects that are moving. If something is not moving, then it's not. If something is moving then it's moving in a straight path - which we don't see as straight because the spacetime is curved. So satellites orbiting the earth go straight through spacetime which is curved and that's why they go in circles. Understanding how gravity works on stationary objects is a bit more tricky. The thing is NOTHING IS STATIONARY. You always move through spacetime, so if you don't change your position, you travel through time (into the future). This is very important - space and time are different aspects of the same thing, spacetime. So if you for example sit in a couch right now, you don't move through space, you move through time. Now, because of the Earth, spacetime around you is curved - not space - spaceTIME. You travel through time in a straight path but because spacetime is curved you actually go off this path and you get redirected to space dimension. When a satellite go around earth it gets redirected from one space dimension to another and that's how it goes around. Now you go through time and get redirected in the same way, but to space dimension - specifically to the earth center of mass. So you travel through time but go off the course and you get pushed to the surface of the Earth. And yes, because of that your time also slows down. Time slows down near massive objects because some of the speed through time gets "used" to being pushed into the space dimension.

Great job explaining a very difficult aspect of General Relativity that is hard to grasp without doing the math. You have a great gift at explaining things intuitively, your students are very lucky to have you as their teacher.

Absolutely fascinating, Mahesh! Each video in your special relativity playlist is helping me grasp the idea that our current physics theories aren't necessarily right or wrong; rather, we embrace and utilize them because they effectively describe and explain the phenomena occurring in the universe.

@bingusiswatching6335

5 ай бұрын

I like this idea. People always praise physics as if it's some sort of truth machine that churns out irrefutable objectivity. Whatever that means. In reality, physics is math done such that it's as close to our observations as possible. There's no such thing as "objective reality", we most likely aren't decoding anything. Just making human models. Still, one can't deny their elegance.

I have one question about the speed of light, but first, I would like to ask something about changing frames of reference. Imagine I stand up and start rotating around my own axis; could I change the frame of reference to assume that I'm standing still, and the universe is the one spinning around me? I know that rotation is a motion which involves acceleration, so this non-inertial motion could prevent this. If that's the case, then my question is answered right there. But if we can apply the change of frame of reference even in this situation, let's do it. In this case, I am not the one rotating, but everything else but me. This would mean that, from my frame of reference, a chair located 1m away from me would be describing a circular motion, drawing a 1m-radius circle around me, right? Now, let's consider something waaaaaay further from me, like a galaxy on the edge of the visible universe, millions of light-years away: This same galaxy would be doing a circular motion around me, drawing a circle with a radius of millions of light-years. Consider that it takes 1 second from me to turn around; from my frame of reference, that would mean said galaxy described a circular motion around me in the same 1 second, but if we try to calculate the circular path it took to do so in this single second, considering it's a circle with million light-years of radius, it surely would mean the galaxy moved faster than the speed of light, at least from my point of view. As I said earlier, a possible answer for this scenario is to understand that my circular motion isn't inertial, so such a change in the frame of reference is not allowed by special relativity. Is this the case?

@thedeemon

5 ай бұрын

In General Relativity you can define such a frame of reference. And it's fine to have some things move faster than c there, c is only a local limit in GR. In Special Relativity, since it's not an inertial frame of reference, it can't be described by a single frame going through time, instead you'll have to switch frame of reference at every moment, which makes that other object's "motion" not a real motion.

I personally hated physics all my life , just becoz of tons of formulas and ridiculously long calculations , I'm 18 now and preparing for Neet ( a premedical entrance test in India ) and I do like the concepts of physics like we got Motion 1D and 2d , Newton's Laws of motions , waves etc . AND I MUST SAY I WATCHED 5 OF YOUR VIDEOS JUST BECAUSE HOW WONDERFUL THEY ARE , it's a piece of art really , and watching this motivated me to go study some physics for my upcoming test 😂 😅b, TYSM bhaiya ❤❤❤❤ , LOVE FROM INDIA

Best explanation I've seen yet.... Understood it easily and covered all my confusions

This is the first I’ve seen of your channel but if your other content is at all similar in content and quality then this has to be the best algorithm based recommendation I have ever received on KZread. Thank you!

Was really fascinated watching your recent videos.. Looking at your views while backtracking, gotta say you have come a long way sir... And your videos are really good too.. Love the way you explain stuff with great passion.. Keep it up

Thank you for this follow up video. For years I've battled with this concept and never knew about length contraction.

Delightful narration, perfect illustrations. Thank you Mahesh.

I feel bad that I found your videos late. But now that I have i want to thank you from the bottom of my heart!

That's very high quality content. Would love to see such a high quality explanation of the twin paradox: why only one of the twins gets old? Pls I didn't understand that even by watching a lot of other videos. By the way, I've clicked the subscribe button at first glance of this wonderful channel!

@Mahesh_Shenoy

5 ай бұрын

Thanks a ton. And welcome. Oh yes, that’s up next. My most challenging project so far!!

@ghegogago8297

5 ай бұрын

Thank you so much!@@Mahesh_Shenoy

@curiousburke

5 ай бұрын

@@Mahesh_Shenoy The conversations you have with famous scientists are incredible! Love it!

@justacherryontop6538

5 ай бұрын

And it's not just a logically correct theory to explain it without contradiction; we have proof of time dilation. One of the twins will be old if the scenario were created in real life. It's like magic, but not just an illusion; it's a true fact of reality...

Explained very well. Great work.

Just came here to let Mahesh sir know , there's none who could have explained electronics better. I hated every diagram and explanation. It was a huge burden for me . Got through the chapter from your electronics lesson @khan academy. I just loved learning it and that was way more interesting. Pretty much all of your vedio lessons are well presented and easy to understand!!! 🙌🙌🙌🙌 thanks a lot sir !

@Mahesh_Shenoy

5 ай бұрын

Wow, thanks :) :)

Great content! Can't wait for your videos on General Relativity!

My head hurts. Not because of the complexity, but how simple it is once explained. Amazing.

What an explanation. What a video. Amazing content... this is probably one of the best videos I have seen in a long time. Great work.

Dude you are changing the world! 70k subs on the way to 20mil +

The best Explanation ever i've ever watched. One of The best Physics channel for me.

Thank you so much for your videos. This is what i was looking for for years, truly. Intuitive understanding of science is really fundamental. If it possible, could you make some intuitive explanation of twin paradox?

@Mahesh_Shenoy

5 ай бұрын

That's coming next!

Thank you so much, you're an excellent teacher and this channel is the only one which finally breaks some mental blockers, and allows me to wrap my head around relativity

@Mahesh_Shenoy

5 ай бұрын

Amazing to hear that.!!

Hi Mahesh, I recent discovered your channel and I find your vidoes very intuitive as you say it. Could you please now add the concept of gravity in relativity to explain the concept intuitively? ❤

Come on bro you are making these concepts interesting and easy❤

this was good! thank you

This is quickly becoming my favorite physics channel. Great work, Mahesh! It's 1am,I have to work tomorrow, and I just played a gig (3 hours of high energy rock), but what's this? An explanation of length contraction? Meh. I'll sleep when I'm dead. Bring it on!

@Mahesh_Shenoy

5 ай бұрын

Oh man, that comment made my day, Kevin! Seriously! Thank you. And welcome to the community :)

This is great stuff. Thank you

Mad respect to you Mahesh!

I like this guys enthusiasm.

proud of you getting a sponsorship, truly an underrated channel.

Awesome! This video was released. Iam a bit late to notice because my locality undergone a power shutdown yesterday. Anyways,thank you for your video.

I Always knew Einstein was a peerless genius. But this explaining what he figured out makes him seem almost supernaturally smart.

Thought of two things just now. The lenght of object, approaching C is constrained from our perspective (up to a material point I believe). It's mass is increasing (up to infinity, if I understand correctly). Making this object effectively a black hole, from our perspective. And making it cause a real impact to us, because of gravity, forcing us to fall onto it. And as we begin falling, I mean as we start to accelerate towards it, it makes relative acceleration between us and the object less than before we start moving. It thrilling relation.

This is for my reference 7:31 to 15:00 Thanks for lecture mr mahesh it was good

Thank you Mahesh, it's was a great explanation. I'll really need these types of explanations for physics graduation.

Hi. Will you make videos about general relativity too? I really hope so. General relativity is something I never understood, but I am very confident you could make us understand. Congratulations for these amazing videos.

Brilliant explanation as was the last. I still dont quite understand it all but I understand more. Love that youtube presented your channel to me. Here is a comment so Algo the algorithm may help you grow

@Mahesh_Shenoy

5 ай бұрын

This is complex stuff. It took me ages to wrap my head around all these (and I am still barely scratching the surface). Thank you :)

I’d love it if you a did a video that explains why gravity causes time dilation. What is the physical reason/process that causes this to happen?

@Mahesh_Shenoy

4 ай бұрын

Yes! I do have a list of general relativity videos lined up!

Damn I realise now I was thinking about it all wrong when commenting. this seems so simple in hindsight. Thank you for the fantastic explanation!

@Mahesh_Shenoy

5 ай бұрын

But, that's the beauty. The more we ask questions, the deeper we go. So thanks for asking!

I was trying to learn this logic from different sources and now i am at right place. Thanks for this explanation, Mahesh👍 👏 👌

@Mahesh_Shenoy

5 ай бұрын

Super awesome to hear this!!

What a brilliant video Mahesh!! Reignited the physics guys within me ( I am a medical doctor btw). Will save these videos for my duaghter once she is capable enough to understand these concepts. U earned a sub brother. Keep up the great work!!

I would love an explanation on why FTL travel breaks causality! Every explanation I’ve seen hasn’t made sense to me

Now I get it. THANK YOU !!

Thanks , your visualization gives a easier way to understand the concept , But I think one thing we still misses , what about color ? , Doppler effect ?

did not expect such a great explanation from keegan michael key

Hello Mahesh, I love your videos and your enthusiasm for this subject is infectious. I'd like to ask a question regarding light-speed travel that has always bugged me. Imagine traveling in a series of nested spaceships, the outermost ship travels close to C with respect to the outside environment. within this first ship is another ship that is capable of traveling at close to C with respect to the ship it is within. You could nest more and more ships within each other and seemingly travel well beyond C with respect to the outside environment. I look forward to hearing why I'm wrong about this, as it has bugged me for years!

Wonderful !! Thank you

I love your videos so much, they are very much the tool I needed to get a more intuitive grasp of Relativity. Thank you so much. I do have a question: two observers or more may disagree on the speed of a given body, but is speed in the universe absolute in this sense: Can I measure my resistance to going faster and thus ascertain what percentage of the speed of light I am traveling? If so, than that percentage of the speed of light is like an absolute speed value for the universe, is it not? In this sense, speed would be an absolute value that i could measure and which all observers could agree to?

brilliant video!,❤

You nailed it.I mean stamped it with red and blue stamps.GPS. love to see a vidio on parallel transportation.

whaaaatt!!! length contraction!! thanks for the explanation!! , subscribed at speed of light!

i find physics and maths really fun and interesting, this video really made relativity understable and i like to think more about it

Amazingly good content! Could you answer one question please: why isn't there length dilation of the ship from the earth's perspective? So if the earth contracts from the ship's perspective, shouldn't the ship correspondingly expand from the earth's perspective? Or is this equivalent to the electromagnetic waves taking longer to transfer energy?

This was such a great video. It squarely addressed my biggest misunderstandings and misconceptions about special relativity. This video should get pinned to the top of all special relativity and faster than light videos on KZread. Great work. EDIT: I look forward to your upcoming video on the twin paradox which still conflates me.

@Mahesh_Shenoy

5 ай бұрын

Wow thank you! Unfortunately, this video is not doing well so far :-/ Anyhoo, working on the twin's paradox as we speak!

This is also a nice visualization for why we see the ship "frozen in time" from our perspective; They also see the earth "frozen in space" from theirs.

I was studying the science of special relativity by einstein, and ur ideas and explanation is helping me a lot, thanks a lot mate :)

@Mahesh_Shenoy

5 ай бұрын

Great to hear that :)

Brilliant job!

0:24 in last video this animation was not clear but u corrected in this one yay🎉

FHP, can you make a video on what the new kilogram is? Just pieceing together your other videos, you're most of the way there already!

This is great stuff. I have felt that after reading enough books, I had about a 99% grasp on the concepts of relativity, but every time I read a new book or see a new video that explains it a slightly different way, I gain a little better "intuitive" understanding of it, like adding a decimal point so I now have a 99.9% grasp of relativity - but just like the speed of light - I never have a 100% grasp of relativity. 😂 Here's my request - because I like your style so much and I wonder how you might add to the intuition of something I have struggled to understand: Can you make a video discussing the chapter "The Frozen River" from Brian Greene's book "The Fabric of the Cosmos". I have read "The Elegant Universe" and "The Fabric of the Cosmos" about...I don't know...20 times...trying to grasp many of the thing he writes, but in "The Frozen River", the idea of all of spacetime existing simultaneously and that being so logically demonstrable by examining the reference frame of a very distant alien moving towards us or away from us...well, this concept has haunted me...because unlike quantum physics, which is so intangible, relativity feels intuitive to me, and so the ideas expressed in "The Frozen River" seem to very logically 'prove' that there is no past, present, or future, but only 'all of spacetime'. But anytime I say that out loud to myself, my mind implodes and I realize that I understand nothing at all.

Bro the length contraction thing can be also explained just using light like for contraction of the road the ship and light from second stamp are moving towards each other hence causing the person in shop to look the stamp faster making it shorter

You are as talented as mr tyson . You have a special skill to teach people about physics

Very enlightening video, you are a great teacher. I have a question: if we consider the frame of reference of a light wave front, then everything else (our matter) is travelling at c? Or how to reframe this?

@Mahesh_Shenoy

5 ай бұрын

Light frame of reference doesn't exist. If we consider it, we are discarding special relativity. Then, we can't use special relativity to make sense of it :D

Very good!!!!

Beautiful. NEVER STOP MAKING THESE VIDEOS!!

Plz make videos on working of different types of machines like motor generator.. etc

Hey, great work Mahesh, but can you also tell us why time dilates because of gravity? Like why it takes so long for an object to fall into a blackhole to an outsider?

Wee meters, the smallest of meters. This is all in good spirits. I love your videos. You’re an astounding teacher. ❤

@ALBINO1D

5 ай бұрын

I lol'd. : D

@Mahesh_Shenoy

5 ай бұрын

I literally didn’t know v and we are pronounced differently. My whole life has been a lie. Time to learn some phonetics I guess 😂

Hey when will you upload about Maxwell’s last equation? Nice video btw.

Hey mahesh please make a video on double split experiment in time dimension, i feel like your explaination will really clear up mine and other peoples mind, because i am just confused lmao!

While length contraction is a very real effect, it wouldn't be quite as visible to a relativistic observer as one might think: light from different parts of an object arrives at different times (light from further parts of the object arrives later), and light from the back of an object that would normally be blocked can end up reaching the observer when the object is in motion (while light from the front that would normally reach the observer can be blocked). As a result, a relativistic object appears to have rotated, and for a sphere, this ends up cancelling out the length contraction, so that while the sphere *is* length contracted, you'd still see a circular outline at any speed (but would see a different side than you would at rest). The event is known as Terrell rotation.

I think what everyone wanted to see was what it would look like from the point of view of someone on the ship who is looking out the front windows (ie, in the direction of travel). Every scifi show set in space has their own version of the starfield effect - how close were they ? What would it really look like to accelerate towards a high percentage of c, while facing the centre of the milky way ?

Hats off bro..... ❤❤❤

Excellent video. Awesome content. Thank-You. Hypothetically, the people inside the ship traveling at c would go from the start to their destination in an instant. Time would be dilated to zero, while the distance traveled would be contracted to zero. So to them they travel the entire distance in an instant. Later when they do the calculations they will have appeared to travel faster than the speed of light. I came across this problem when determining the outcome of light radiating from distant galaxies. Light travels at c, so to it when traveling at c to an outside observer, in this case the telescope is doing the observing, then the light experiences time dilation and length contraction. Light is the only thing in the universe currently able to experience this observer effect. Telescopes then should see this observer effect when measuring galaxies extremely far away because in order to measure the distant galaxy the telescope would have to be contained inside it's EM field. So all the photons will be entangled. Thus why in the first book I published in 2021, almost 3 months before the JWST was launched I wrote quote, "The JWST, James Webb Space Telescope will discover old, fully grown galaxies as far as the telescope can see, further than 13.8 billion light-years away." And sure enough that's exactly what the telescope found. It discovered one galaxy F200DB-045 extremely far away, having a redshift of z=20.4, placing it at at about 13.62 billion light years away. The galaxy F200DB-045 contains a supermassive black hole in it's core weighing an estimated 100 million solar masses. I was spot on. At that distance because the telescope is contained inside the galaxy's light cone then they're measured in our relative time, as they look today, not as they looked in the past. Note this observer effect doesn't happen to reflected light, only to the light coming directly from the star or galaxy. Reflected light takes time to travel but light that is entangled inside it's own EM field becomes entangled. Thus the observer effect, time dilation and length contraction occurs to all it's light information. Instant, spooky action at any distance. We see the distant galaxy as it looks today, in our relative time. Not how it looked in the past. Light information from the past is long gone.

Mahesh another great video! I'm wondering what do I see if the space ship is clear and I look at the spaceship travelling almost at the speed of light and then someone gets up at the back of the ship and walks forward. Does the time dilation slow him down so much that to me I only see him move at < C minus the speed of the ship

Nice video! These days I was thinking about it and came to a question that is linked to this video: Distances in space are measured in "light years", which should mean: "how many years it takes for a photon to travel that enormous distance". But, when I see articles calculating the time it would take (from a hypothetical ship's perspective) to travel that distance at 90% the speed of light, usually they result in less years than the initial distance in light-years, which, in my mind, should be impossible. For instance, if a distance between Earth and some galaxy is 100 light years, they say it takes less than 100 years if you have a 99%c ship. They attribute this to time dilation/length contraction, but I could not grasp the real meaning. If it'll contract for us at 90%, why don't they apply that when measuring the distance in light-years? And my second thought when I see your video is... Aren't we maybe traveling almost at light speed if we compare to some other random galaxy that's getting away from us? Or if we compare to a photon emitted by our sun that is escaping our solar system? On the point of view of the photon, earth is moving at light speed, isn't it? I'm not sure those are questions or just me understanding it... Would we have any advantage by traveling at light speed? Or only if we could "steer" our Earth-ship to the direction we want? :) Thanks for your work.

@thedeemon

5 ай бұрын

Proper time for the ship (how much passes on its own clocks) is reduced γ times. In the ship's perspective the distance is also reduced γ times, so that for the ship it looks consistent: we take less than 100 years to cross the distance that's now not as long. For a static observer on Earth, the distance remains 100 units and the ship's trip still takes more than 100 Earth years.

@NickUSHOR

5 ай бұрын

This is correct. Once you go above 99.9% the speed of light, the effects of relativity get exponentially larger. So the ship would actually reach the edge of the universe in a few years of spaceship time, but the universe along with the earth will have aged billions of years.

@Fluxikator

5 ай бұрын

To the first paragraph: they don't do that because we can only measure distances from earth. So it's all relative to earth. You can infer distance from time dilation. So if it's takes you just 2 years for a 4 light year trip. You're probably around a gamma value of 2 so the distance for you ist basically halved. It's two light years. (A bit more than that. Because you're going slower than light) Depending on how fast you go a distance of 1 light year could possible shrink down to one meter. Given a high enough velocity. On you second paragraph: galaxies moving away from us is due to the expanding universe. That's not a movement through space. Spacetime between both gets more. (Imagine inflating a balloon with dots on it. No dot moves relative to the balloons surface but while inflating they still move apart. And relativity cannot be applied to the expanding universe. As for the photons: Never think in terms of "at light speed". Photons don't experience time. From the viewpoint of a photon. The distance from their origin to the destination is 0. Nothing basically moves because there is no distance at all.

@ricfwolff

5 ай бұрын

@@Fluxikator Thank you! That makes sense indeed.

Your explanation was really amazing but i didn't get why would the acceleration be samller when the length is contracted 17:03 ?

nice videos!

But Mahesh, can Einstein tell me why my head now hurts after watching this video? Honestly I love the videos on this subject, they have been a great learning experience.

I mean you are great. In my 39 years of like i couldnt understant that, but i could by watching this video. Thank you very much!

8:45 (ish) in the ships frame, their clock is already slowed, and 1 tick takes 2 real seconds, so they travel 2V before making a mark even in their own frame. Two things that are stationary and emitting photons 1 light second apart(or more), will, from any point in space at any instant appear 1 light second apart, by angular measure, by any sort of calculation. If you happen to be moving at some speed X when you're at that point, you'd still see them 1 light second apart. The rest of the universe has no mechanism to shrink relative to your motion. Can even specify that you must be heading in a specific direction of A=arccos(v/c) so the light aberration has 0 effect... otherwise you have to back-calculate actual positions based on your known speed - which can be measured in the aberration of things around you, and the relative speed by which they are whizzing past you. Yes - I understand the typical explanation is to say 'no, 1 second is still 1 real second, even though it's not, it's known to be contracted in all frames that can see the clock' and then contract the length... and that explanation ignores that the clock of the moving ship IS running slower already. So you're saying we can't ever go faster than 0.707c. gamma at 0.707c = 1/sqrt( 1-0.707*0.707)=1.414 (side note 1/1.414=0.707), so the clock goes 0.707 times as fast, so travelling at 0.707c for 1 local second (which is in reality 1.414 seconds), you're actually going 0.707*1.414 =1 ... 1 light second per second. The outside world sees you travel 1 light second in 1.414 seconds. If your ship emitted a pulse every second outside observers would see a pulse every light-second, 1.414 seconds apart. (If the universe was somehow shorter) If you decided to contract the length then - you'd emit 1 pulse every (real) second and cover 0.707 light seconds every second, but that 0.707 light seconds was actually 1 light second of real space. and you're still going 1 light second per second. If there was a marker every 1 light second, you'd see it shorter and it would appear to only be 0.707 light-seconds per mark. Length contraction really doesn't solve the problem. At the end of the trip you stop and observe how far you went... if you went 4 light years to the nearest star at 0.707c, your local clock would tick 4 years, and your distance would be covered as 4 light years. If you assume your clock is real time and isn't dilated then you'd only have to cover 2.828 lightyears at 0.707c - which takes 4 years, and when you stop you find you've really covered 4 light years, even if during the trip it somehow seemed like 2.828 lightyears. And of course anything faster than 0.707c would appear to the local frame to be faster than the speed of light.

I’d like to see videos on quantum and general relativity or even more obscure theories

Speaking of relative speed the fact we are moving nearly 500,000 mph through the universe always blows my mind!

@extravagantpanda7962

4 ай бұрын

And that speed itself is relative to something. It is equally valid to say that the earth is moving at 99.99% of the speed of light in some reference frame (such as that of a passing neutrino emitted from the sun).

11:56 There’s an issue with this animation. Remember, the *stamp* is traveling with the ship. It, and therefore the mark it leaves behind, should keep the same shape from the ship’s perspective. The marks are actually elongated from the platform’s perspective. Why elongated, when from the platform’s perspective the ship is contracted? Because of lack of simultaneity; the back of the stamp hits first.

@danielrhouck

3 ай бұрын

Also, I’d appreciate a sequel to this video about Rindler horizons and such; I still can’t quite wrap my head around them.

i'm just wondering with the stamp thing, from the ship's frame the stamp is bigger compared to the platform because the platform appears contracted, but from the platform's frame the ship has contracted so the stamp should be smaller from their perspective. which, if either of these is true? edit: i see this is actually quite similar to the twins paradox, i just started watching that video now.

When we say ship is travelling at v m/s, we should also clarify that its ship speed as measured from the platform's perspective. or if platform is moving at v m/s, we should clarify that its travelling at v m/s as measured from the ship. Now coming to the paradox... if A relative to B can also be said as B relative to A, doesn't it takes 2 seconds when platform was moving?

Really enjoy your videos and they have me thinking about a scenario that I can't wrap my head around. What if there were 3 space stations equal distance apart and on the same reference plane, from the center station, 2 ships departed at the same time traveling in opposite direction from each other to the outer stations. They are traveling at 75% speed of light from the stations' reference. Would the ships apear to be traveling at 1.5x the speed of light away from each other? Could a message traveling at the speed of light make it from one ship to the other before they reach their destination?

Can you make a video explaining Twin's Paradox now that you have explained time dilation

@Mahesh_Shenoy

4 ай бұрын

Yes, that's my next video :)

Wow 🙏👍 great lecture Mahesh sir, suppose if you are travelling on a photon some how, then because of length contraction doest it mean that you are every where instantly because length is zero at C ?🤔

@Mahesh_Shenoy

5 ай бұрын

You can’t travel at c :D. That would break relativity. And if you break relativity, all bets are off!

The thing I dont get is, what is a resting state? What is resting in the universe? Wasn't movement supposed to be relative to objetcs? Or is there an objective frame of reference in space?

Love your explanations and enthusiasm. I could listen to you forever. However, if nothing can travel at the speed of light then how can photons do it? Sorry if you have already answered this.

Hi Mahesh, This question will really challenge you. You are saying that in a spaceship approaching the speed of light from the Earth's perspective, the acceleration will gradually slow down due to the slowing down of the progress of electromagnetic waves due to time dilation and the spaceship will never reach the speed of light. However, on the other hand, when viewed from the Earth's perspective, the spaceship's length will decrease in the direction it accelerates. Therefore, the distance that electromagnetic waves must travel between atoms will be reduced to almost zero. So compared to Earth, time will almost stop, but the size of the spaceship will also decrease to almost zero. In this case, why is an interpretation made only by taking time dilation into account and it is predicted that the progress of electromagnetic waves between atoms will gradually slow down? As a result, both time and distance are multiplied by the Lorentz Factor and time becomes shorter.

Excellent channel and brilliant explanations. However, in this particular case about length contraction and time dilation you have to take in account that there are 2 clocks not just one in two different states (motion and rest). The second clock which is “observed” from the platform is just a virtual clock. One of those frames of reference must be actual and the other one virtual, in order to get relativistic effects. In other words length contraction and time dilation take place in a frame reference where there is not a physically present observer, what means they occur just hypothetically. In 2 words: it’s like to say that they take place “hear from there”. The real problem with relativity arises, according to Einstein, when we start to evaluate the same event from different frames of reference. In my opinion this is not possible: from different frames of reference we do not evaluate the same event. Once again, this is a great channel, one of the best, in my opinion. Keep working on it, please. I’m going to subscribe right now.

I have a few questions that I’d appreciate someone answering :) If the ship were to decelerate and come to a stop, where would it be in space and how far away from where it started Now that both the observer and the spaceship are at similar relative speeds, how long has passed for both the person in the ship and the observer

It’s possible to “effectively” travel at any speed without limit. You can travel to a star 5 light years away, in a day for example (in ship time), due to the length contraction / time dilation.

I have questions. If there are 3 povs. 1st acc to left, 2nd to right, and 3rd stationary. How is the time dilation, and length contraction on each pov? Is the 3rd see the 1st and the 2nd age slower at same pace? What about the 1st and 2nd pov? What if the 1st and 2nd turn back to the starting point? Is there any age difference, because on 1st pov the 2nd should be age slower right?