Lundmark and Lemâitre 1924-1927 The difference is Lemâitre matched the observations with Einstein's equations. Although, considered tired-light model, anyways...
Sir, can you make video about Einstein field equations explaining 1. Spacetime & Special Relativity 2. Gravity as Curvature 3. Energy-Momentum Tensor 4. The Metric & Geodesics 5. Einstein’s Thought Experiments 1. Explain Gravity as Spacetime Curvature - Show how mass and energy bend spacetime. 2. Break Down the Einstein Field Equation - Simplify its meaning without heavy math. 3. Show Its Real-World Applications - Black holes, gravitational waves, and GPS accuracy.
@@Celestiallearn369 Lecture "Ron Hatch: Relativity in the Light of GPS | EU2013" Lecture "Stephen Crothers: General Relativity - a Case Study in Numerology | EU2015"
We need teachers like you so that kids can be curious to ask more questions and seek for more answers. Honestly it's hard to believe that kids/people nowadays have access of such content for free and readily accessible.
This presentation is needed to be shared to the people that don't understand how science works. Some don't believe because they can't fathom it took a team of scientists not all working together. But sharing what they know so we progress over time and now stand at the edge of new discoveries . Great job.
Long Before discovering your channel, I watched your khan academy lecture on magnetic hysteresis. That lecture was definitely the best lecture I have ever attended. It helped me a lot to become better teacher for my students. So one day I was binge watching your videos and suddenly I realised you are the same person who taught me about hysteresis! Very delightful experience. Keep making videos ❤
@@HarshSrivastava-ez7ke bro spinning black holes are really interesting and very few explanation are there on the internet, It would be interesting to see him make a vid about it
Dudes you’re one of the best science educators to ever be on this platform. You make physics and astronomy so easy and intuitive to understand. Thank you for all of the work you do, Mahesh!
Thank you a lot for mentioning Slipher!! When i learned about him i simply realized that for the sake of giving a single person's name to a scientific law, you end up forgetting a lot of the people that came before and will never be remembered. Scientific discoveries are a product of humanity not of a single person, we keep forgetting that, specially in these days.
Thanks for giving credit to Henrietta Leavitt for her contribution to astronomy. BTW, the correct pronunciation of “Cepheid” is “seh-fee-id”. These pulsating type stars were first observed in the 1780’s in the constellation “Cepheus” which is pronounced “seh-fee-us”. These variable stars were named for this constellation.
Could you also someday talk about how galaxies were discovered in the first place? It's so interesting and exciting to learn about the actual journey to the discovery rather than the fact itself. I love your way of storytelling and arriving so naturally at the final conclusion. It must take so much care and effort for preparing that. Thank you
I was watching Rajan Chopra's Video on fake Educational influencer and in its comments many of them were really appreciating your videos on how you explain every thing using mathmatical expression and your awesome intuition on complex topics.
Hey, this is unrelated but has been bothering me for quite a bit now. It's related to power and heat formula for resistors. H/energy consumed=Voltage*Current*time. So here we are basically multiplying charge moved from one end of the resistor to the other. Which is correct (H=VQ) but my question is what about the charges that are already in the resistor? This formula accounts for the charges that we moved from one end to the other. What about the heat that is produced by other charges that are in front of the selected charges and behind the selected charges in the resistor? They too are constantly producing heat and part taking in collisions. Imagine our charge is in middle of the resistor. So when it starts moving the charges behind it and in front of it will move as well meaning they'll generate heat but this formula doesn't account for that. It only accounts for the heat produced while moving those charges from one end to the other but what about other charges? They too produce heat from all the collisions. Where is that heat going? Please answer anyone including you sir.
1. How did Slipher know that the spiral nebulae are red shifted, instead of just red? 2. How did Leavitt know that all chepheid variables that she was observing (the ones in the Magelanic cloud) are at the same distance? Just because 2 objects in the sky look closer to each other, it does not mean that they're actually close together. In fact, 2 stars on the opposite sides of the sky can be actually closer to each other, than 2 that look in the the same direction from us...
Great questions 1. You look at the spectra of various elements. Elements produce distinct pattern of sharp wavelengths which we can study in labs. It forms their signature and that’s how identify them. If all the wavelengths of that signature are slightly shifted, then we conclude it’s the same element but the source is moving. 2. When you detect stars from a particular galaxy let’s say, it’s highly likely that the stars are part of that galaxy because the ones behind them would be obscured. It’s also possible that these could be from the ones in front, but you look at a bunch.
How I wish the indian education system had more people like you in the positions of power, I'm damn sure you could write a book million times better than NCERT
I wish these scientists can watch this video now. What's intuitive for us was groundbreaking for them. . But fun is to realize that our future kids will think in the same way.
Mahesh has become my favorite physics teacher, which is saying a lot because I didn’t understand it well in college. I look forward to these videos as they open a whole new and fascinating world I didn’t comprehend before, but he makes it clear. Thank you, professor!!
I'm doing a uni course on galaxies and could never understand cepheid variable and how we use them to find distances, this video helped me so much thank you ❤
Hubble actually based his measurement of the distance to Andromeda on the work of Henrietta Leavitt, a Harvard statistician, who measured the relationship between the pulsation rate of Cepheid variable stars and their brightness. She found that the pulsation rate was directly related to their intrinsic brightness. If one knows their intrinsic (true) brightness then by measuring their pulsation rate and then measures their apparent brightness, one can calculate their distance by using the inverse square law for brightness fall off with distance. Leavitt verified her findings by measuring several Cephid variable star’s apparent brightness within a globular cluster whose distance was known by using the parallax technique. In this way the distance to an observed Cephid variable could be determined by measuring its pulse rate and it’s apparent brightness. This is what Hubble used to determine the distance to the Cephid variable in Andromeda. His calculations placed it well outside the Milky Way galaxy showing that Andromeda was a separate galaxy, and thus expanding our knowledge of the vastness of the universe. Leavitt is rarely given credit for her work. Hubble himself said that she should have been awarded a Nobel Prize for her contribution. Today Cepheid variables are one of the “standard candles” for calculating distances in the universe. They have a limitation in that for very distant objects, they may be too dim to observe individually, but there are other techniques such as 1a supernova brightness, and others.
I am currently reading "A Brief History of Time" and I was surprised to learn that according to Hawking's Radiation, the bigger the black holes, the colder they will be. If the black hole is 4 times bigger than the Sun then the temperature of this black hole will be -273.15 Celsius which is slightly above absolute zero. Stephen Hawking is Genius.
I've always struggled with an apparent contradiction in these discoveries. The Friedman and Le'Maitre (F/L'M) work and other early work with the Einstein Field Equations always assumed a homogenous, isotropic universe. That makes sense post- Hubble. BUT, F/L'M did their work (≈1922) almost a decade before Hubble's Law, (1929). Instead, they were doing this about the time of "the great debate" on spiral nebulae (Shapley- Curtis '20-'21). My issue is that when F/L'M did their work, the general consensus was that we lived in an isolated "island universe." We knew there was a disk shape and a central bulge to this island. They got the size and our position wrong, but still they got the shape right. This view would not agree with a universe that looks the same in all directions or in all places. In fact, anyone who looked up knew the sky was different in different directions and times of the year. The Milky Way is hard to miss if you don't have light pollution. I understand simplifying a problem, but it feels like their simplification defied observation. I'm surprised no one was looking at disk universe solutions to GR.
(1:45) The much more simple solution to that question is: Because (a) matter is equally distributed on a global scale, (b) matter on cosmic scale is extremely thinly distributed, so that "friction" (or "collision"), which is the necessary precondition of "clumping", does happen only on a tremendously rare scale, and (c) all non-clumping matter settles in rotation systems, because those rotation systems always constitute stable systems for those non-clumping matter. As far as those conditions apply (and they do), EVEN IF something like galaxy intermingling takes place, you do never end up with "one big chunk of blob", but instead always with rotation systems that look principally not other than the ones before the intermingling. Occasionally you get bigger black holes in the center of those intermingling, but that's, too, extremely scarce. You do not need any wild dark energy or such nonsense. Just plain simple newton mechanics and a little feeling for the extreme thinness of outer space. (18:30) The same goes for the "hubbles law": What this is stipulating is only applying in the case of a completely static universe - except for radial movement, and even that only in case of radial movement AGAINST OUR SELF (earth centric world model - in case that's something known to you). As soon as you assume a world model of rotating structures beyond galaxy level, the dependency of cepheid candles to red shifts can equally well stem from relative movements in those rotation systems. i didn't here or read of anyone ever in the last 50 years of my life who had dared to try ANY other model than the geocentric "everything expends away from earth" model.
But if the center of mass of rotation for distant galaxies is not moving away, then why would the speed of rotation away from earth increase. If galaxies are rotating around a hypothetical earth center, then that would be at right angles to the earth center and not produce any Doppler shift at all.
@@AllanAngusADA There is a kind of "sticky thinking" in your argument: Since you clamp on the model of "exclusive radial movement from earth" (arguing "why should the speed ... AWAY FROM earth"), you are not able to even consider arguments for other kind of models. The priests of the inquisition 500 years ago will also have questioned the "new model" in that type of argumentation: Why should we put the sun in the middle when she is clearly visible perfectly rotating around earth?!" You should go on a ride with a turntable together with some other guys, do NOT place yourself exactly in the center, and then let the guys throw little stones at you, then protocol the velocities and directions of the incoming stones! You can, as well, write a little emulation to do the trick for you - if you are able to write programs. Report back as soon as you have the results!
@ I think you miss the point about the expansion of space overall. All distances expand between any two points. The absolute rate of expansion is higher for the larger distances. This is not at all centered on Earth or any point. There is no center point nor any rotation which would violate conservation of angular momentum if there were no rotation showing in the CMBE.
@@AllanAngusADA The term "All distances expand between any two points" does stipulate nothing about where we (earth) position ourselves in the "observable universe". What produces that latter stipulation, however, is the stipulation that the observable universe is surrounding us to all directions in the exact same mannor, and that this observable universe shall end at about 14*10^9 ly distance. These two terms together force the stipulation of earth being in the absolute center of the whole thing. Else, you would be required to watch differences for any opposing vectors. What you do not - according to publications of observations so far. That's the current "accepted" model. And is gets confronted with a daily growing amount of discrepancies. We are at a point where what we see is not what our models according to those "accepted" theories predict. That is a mirror of the situation around 1500, when Kopernikus and Gallileo (and a bunch of other less known colleges of their time) challenged the old "accepted model" of the european church. What the defenders of the old "accepted" model did, was to add more and more specific appendices to their old model to make it fit the newer observations to be able to clamp on it just a little longer, until the next better observations stumbled in. That, too, is a mirror of the current situation in astrophysics. Good luck with that policy! :D The difference between charlatanry and science is, that science can make predictions that hold - for eternity. Newtons laws of gravitation and mechanics hold up to the current day: You can perfectly well calculate motions of objects in our solar system forward and backward in time based on those laws and you will end up with predictions that HOLD - to the accuracy of the measurements at the start of the calculation. THAT is science. Literally EVERY DETAIL that got predicted for the distance at about 13*10^9 ly away based on the best of "adjustments" of the "currently accepted model" just 20 years ago gets contradicted by literally every observation that comes in from the James Webb Telescope. With literally EVERY single observation, you can read about "contradictions" and "new adjustments" to what those idiots think about how their model could possibly work despite all that shit. That is charlatanry.
Can you make a video about this: Times moves slower in moving objects. If Tom travels away from Claire at 0.99c and then returns he would have aged slower. But why? If you look at it from Toms perspective Claire is the one thats moving. Him accelerating could be seen as him decelerating. Who did age more when they meet again?
Mahesh Sir, could you please bring that informative video on dark matter and dark energy? It presents some recent and groundbreaking findings that shed light on these intriguing subjects, and I believe it will greatly enhance our understanding of the universe!
Quran 51:47 "We built the universe with ˹great˺ might, and We are certainly expanding it." How could a book 1400 years ago contain the recent discoveries?
There are many more Quran 21:30 "Do the disbelievers not realize that the heavens and earth were ˹once˺ one mass then We split them apart? And We created from water every living thing. Will they not then believe?"
Although I knew many facts, I really enjoyed watching your video, thank you! If you ever get bored of expaining fully accepted theories, I‘d be very keen to see how you would explain / discuss Roger Penrose’ conformal cyclic cosmology / CCC theory to a broader audience here in your channel. I find it very convincing, even when it is still a not yet prooven theory.
It might be overkill, but when it comes time for me to drink the remaining milk from my bowl of cereal, I always pause the video to make sure I don't miss anything.
On the topic of Big Bang, can you please make a video on cosmological inflation? How is it even physically possible? Or is there anything we are still missing and cosmological inflation is just a "placeholder" theory until we get the real picture?
Dark energy in theory is the cause of the aceleration of the expansion of the universe, it has never been proved existince but its believe to, because in einstiens theorys the universe should already be shrinking because of the gravity of mass objects of the universe but thats not what observed, but it could more be that the expantion of the universe just a ilusion from our small observible part of the universe because of a hyperbolic form of the universe
Hey Mahesh can you please make a video explaining the most fundamental particles (fermions and bosons) and how they interact with each other for formation of matter?❤
I could be wrong, but didnt recent research show the observed expansion to be an illusion of a non-uniformly densed universe? Which causes the light to be red shifted in large portions of empty space
Hi i really liked this video, for a while i have been hooked on your videos and wait for them to release, i was wondering where do you generally learn about stuff like this?
Hi Mahesh, would you consider doing a video on Timescapes? It seems interesting, but I feel like you are the only person who can possibly articulate it for a layman like me. Thanks for all that you do!
@@Mahesh_Shenoy I am so sorry! I missed the ending of the video where you mentioned the steady state universe. Thank you so much Mahesh, you are amazing! :)
Hi mahesh, i’ve never understood magnets in physic. Could you makea video about them and about what makes a piece of metal a magnet and which is the mechanism that makes a magnet attract other body? (Maybe you’ve already made this kind of video, if you’ve done it, i apologize)
1:25 But the "Shell Theorem" states that a spherical shell has no gravity inside. So at any location, a homogeneous universe (being made of a sequence of enclosing spherical shells) has no force to make things clump together. So Newton's answer would be that the Universe would not collapse, would be stable. (Just search for the Shell theorem)
Was it discussed here how they calculated to get “true brightness” from the relationship between “apparent peak brightness” vs “period”? Or was that calculation skipped here? Where in the video was it explained if I missed it.
Thanks Mahesh for making such content. This video makes me wonder that can a star transition from one galaxy to other or it’s not possible because of the expanding galaxies?
Hiii nice video n if possible can u make a video on Big bang in a much more detailed way like is it the beginning of time, could there be manny Big bangs n ours is just one of them? Etc
One way is to look at their spectra. Elements like H and He have characteristic absorption frequencies (they'll appear as black bands in the visible spectrum). Those bands will be shifted toward the infrared if the star is moving away.
Hubble said that redshifts also could mean earth is in the center of the universe (observational approach to cosmology book) and that they think that option is horrific, Stephen Hawkings said in "grounds of modesty" they don't want to choose the earth centered paradigm. General relativity allows earth to be at center of universe, is just a different coordinate system, in einstein's own words. Geocentricism is better then current model system in explaining the sky, it does not require dark matter and dark energy to make it "work" as big bang model does (and nobody even knows what DM/DE are {nothing more than mathemagic trickery}). Parallax and aberration are also explained in geocentrism as well! MMX experiment proves earth does not move around the sun, Michaelson gale Proves sidereal rotation of the universe. Watch the principle from 2014
I've often wondered if, rather than the universe expanding, could interstellar dust be the cause of the red shift we observe. Just as the sun appears redder as the light cuts through more atmosphere at sunset, could light from distanct galaxies similarly be affected? We treat space as a perfect vacuum, but there is some matter floating out there, and over a great enough distance, like the distance between galaxies, could have a compound effect? The more distance the galaxy, the more stuff in-between, hence the greater the red shift. I'm no astrophysicist and probably don't know enough about optics, so my conjecture has probably already been taken into account and thoroughly debunked.
Bro literally added historical context to a lot of things I already knew but I feel like I learned a lot more. Like, Leavitt's Law is no longer talked about probably because now Hubble's Law can be used to measure distances and you no longer need to find a Cephied variable star (Idk. I'm not an astro physics guy, just guessing.)... But it is an indisputable fact that Hubble could only discover his law because of Leavitt's law Yeah... History makes science education a lot easier
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Lundmark and Lemâitre 1924-1927
The difference is Lemâitre matched the observations with Einstein's equations.
Although, considered tired-light model, anyways...
I don't understand how the universe can expand from every point.
Sir, can you make video about Einstein field equations explaining
1. Spacetime & Special Relativity
2. Gravity as Curvature
3. Energy-Momentum Tensor
4. The Metric & Geodesics
5. Einstein’s Thought Experiments
1. Explain Gravity as Spacetime Curvature - Show how mass and energy bend spacetime.
2. Break Down the Einstein Field Equation - Simplify its meaning without heavy math.
3. Show Its Real-World Applications - Black holes, gravitational waves, and GPS accuracy.
@@Celestiallearn369 Lecture "Ron Hatch: Relativity in the Light of GPS | EU2013"
Lecture "Stephen Crothers: General Relativity - a Case Study in Numerology | EU2015"
DON'T BE A d^3x/dt^3 Mahish said.
U ~ε Q, d^4x/dt^4! Smart replied
Man you are one of the best science communicators.
I like his enthusiasm, but more importantly he can give a different angle and show how to get a deeper understanding.
That's not a real term. A science communicator is just a scientist. Stop spreading psyops.
We need teachers like you so that kids can be curious to ask more questions and seek for more answers. Honestly it's hard to believe that kids/people nowadays have access of such content for free and readily accessible.
This presentation is needed to be shared to the people that don't understand how science works. Some don't believe because they can't fathom it took a team of scientists not all working together. But sharing what they know so we progress over time and now stand at the edge of new discoveries .
Great job.
This is what I love with science: building upon the predecessors, collaborating with contemporaries, passing to the successors
Long Before discovering your channel, I watched your khan academy lecture on magnetic hysteresis. That lecture was definitely the best lecture I have ever attended. It helped me a lot to become better teacher for my students. So one day I was binge watching your videos and suddenly I realised you are the same person who taught me about hysteresis! Very delightful experience. Keep making videos ❤
Vote for black hole structure
Vote for rotating black holes
Bro there is nothing scientific for us to know about black holes instead of basic terminologies.
Yeah we want mash senoy
@@HarshSrivastava-ez7ke bro spinning black holes are really interesting and very few explanation are there on the internet,
It would be interesting to see him make a vid about it
Yep 👍
Dudes you’re one of the best science educators to ever be on this platform. You make physics and astronomy so easy and intuitive to understand. Thank you for all of the work you do, Mahesh!
well astronomy is a part of physics anyway, but ye i get your intention
Even his shirt is more information than my school teachers
Thats incredible to have you back with a cool content.
Thank you a lot for mentioning Slipher!! When i learned about him i simply realized that for the sake of giving a single person's name to a scientific law, you end up forgetting a lot of the people that came before and will never be remembered.
Scientific discoveries are a product of humanity not of a single person, we keep forgetting that, specially in these days.
Thanks for giving credit to Henrietta Leavitt for her contribution to astronomy. BTW, the correct pronunciation of “Cepheid” is “seh-fee-id”. These pulsating type stars were first observed in the 1780’s in the constellation “Cepheus” which is pronounced “seh-fee-us”. These variable stars were named for this constellation.
That is awesome back story thanks
Could you also someday talk about how galaxies were discovered in the first place? It's so interesting and exciting to learn about the actual journey to the discovery rather than the fact itself. I love your way of storytelling and arriving so naturally at the final conclusion. It must take so much care and effort for preparing that. Thank you
Vesto Slipher has gotta be one of the most badass names I've ever heard.
Don't be a jerk. 😂 (Jerk = d^3x/dt^3)
Said Mahish.
You are ∉ Q. d^4x/dt^4 ! Smart replied
I didnt get it
@ I don't get it this time.
@ "You are irrational. Snap!" Smart replied.
@smart3go Ahh~ I see it now.
I was watching Rajan Chopra's Video on fake Educational influencer and in its comments many of them were really appreciating your videos on how you explain every thing using mathmatical expression and your awesome intuition on complex topics.
Hey, this is unrelated but has been bothering me for quite a bit now. It's related to power and heat formula for resistors. H/energy consumed=Voltage*Current*time. So here we are basically multiplying charge moved from one end of the resistor to the other. Which is correct (H=VQ) but my question is what about the charges that are already in the resistor? This formula accounts for the charges that we moved from one end to the other. What about the heat that is produced by other charges that are in front of the selected charges and behind the selected charges in the resistor? They too are constantly producing heat and part taking in collisions. Imagine our charge is in middle of the resistor. So when it starts moving the charges behind it and in front of it will move as well meaning they'll generate heat but this formula doesn't account for that. It only accounts for the heat produced while moving those charges from one end to the other but what about other charges? They too produce heat from all the collisions. Where is that heat going? Please answer anyone including you sir.
1. How did Slipher know that the spiral nebulae are red shifted, instead of just red?
2. How did Leavitt know that all chepheid variables that she was observing (the ones in the Magelanic cloud) are at the same distance? Just because 2 objects in the sky look closer to each other, it does not mean that they're actually close together. In fact, 2 stars on the opposite sides of the sky can be actually closer to each other, than 2 that look in the the same direction from us...
Great questions
1. You look at the spectra of various elements. Elements produce distinct pattern of sharp wavelengths which we can study in labs. It forms their signature and that’s how identify them. If all the wavelengths of that signature are slightly shifted, then we conclude it’s the same element but the source is moving.
2. When you detect stars from a particular galaxy let’s say, it’s highly likely that the stars are part of that galaxy because the ones behind them would be obscured. It’s also possible that these could be from the ones in front, but you look at a bunch.
How I wish the indian education system had more people like you in the positions of power,
I'm damn sure you could write a book million times better than NCERT
I wish these scientists can watch this video now. What's intuitive for us was groundbreaking for them. . But fun is to realize that our future kids will think in the same way.
Mahesh has become my favorite physics teacher, which is saying a lot because I didn’t understand it well in college. I look forward to these videos as they open a whole new and fascinating world I didn’t comprehend before, but he makes it clear. Thank you, professor!!
I'm doing a uni course on galaxies and could never understand cepheid variable and how we use them to find distances, this video helped me so much thank you ❤
I like your t-shirts and was amazed to know that you design'em
For the record, this particular one is NOT original. But I do have some original ones in the mix :)
I am waiting for your video for a long time 😭
Back with a bang🔥❤️
The video I was waiting for 😅
Good presentation, passionate and engaging.
14:47 graph:curvy ups and downs
Physics: oh that's a straight line
Hubble actually based his measurement of the distance to Andromeda on the work of Henrietta Leavitt, a Harvard statistician, who measured the relationship between the pulsation rate of Cepheid variable stars and their brightness. She found that the pulsation rate was directly related to their intrinsic brightness. If one knows their intrinsic (true) brightness then by measuring their pulsation rate and then measures their apparent brightness, one can calculate their distance by using the inverse square law for brightness fall off with distance. Leavitt verified her findings by measuring several Cephid variable star’s apparent brightness within a globular cluster whose distance was known by using the parallax technique. In this way the distance to an observed Cephid variable could be determined by measuring its pulse rate and it’s apparent brightness. This is what Hubble used to determine the distance to the Cephid variable in Andromeda. His calculations placed it well outside the Milky Way galaxy showing that Andromeda was a separate galaxy, and thus expanding our knowledge of the vastness of the universe. Leavitt is rarely given credit for her work. Hubble himself said that she should have been awarded a Nobel Prize for her contribution. Today Cepheid variables are one of the “standard candles” for calculating distances in the universe. They have a limitation in that for very distant objects, they may be too dim to observe individually, but there are other techniques such as 1a supernova brightness, and others.
Excellent explanation of astronomical distances estimation
Your videos open my mind and make studying a lot easier.
Glad to hear that!
Love your videos❤! Please make a video on total internal reflection and related topics
16:00 was pure goosebumps
Love your vids
I never tire of learning.
Consider learning grammar then
@ tyre?
Good job Mahesh. I like your entusiasm, clear explanations, knowledge. Greetings from Poland.
I am currently reading "A Brief History of Time" and I was surprised to learn that according to Hawking's Radiation, the bigger the black holes, the colder they will be. If the black hole is 4 times bigger than the Sun then the temperature of this black hole will be -273.15 Celsius which is slightly above absolute zero.
Stephen Hawking is Genius.
Absolutely loved it. Can't wait for the next part where you reveal how Einstein's biggest blunder was not a blunder after all.
Just learnt about distance mesurment in Space a few days ago
What a coincidence
Love your work from the academy btw awesome vid
I've always struggled with an apparent contradiction in these discoveries. The Friedman and Le'Maitre (F/L'M) work and other early work with the Einstein Field Equations always assumed a homogenous, isotropic universe. That makes sense post- Hubble. BUT, F/L'M did their work (≈1922) almost a decade before Hubble's Law, (1929). Instead, they were doing this about the time of "the great debate" on spiral nebulae (Shapley- Curtis '20-'21).
My issue is that when F/L'M did their work, the general consensus was that we lived in an isolated "island universe." We knew there was a disk shape and a central bulge to this island. They got the size and our position wrong, but still they got the shape right. This view would not agree with a universe that looks the same in all directions or in all places. In fact, anyone who looked up knew the sky was different in different directions and times of the year. The Milky Way is hard to miss if you don't have light pollution.
I understand simplifying a problem, but it feels like their simplification defied observation. I'm surprised no one was looking at disk universe solutions to GR.
yayyyyy new vid! just found this channel recently
Vote for rotating black holes
To be able to get an uneducated person like me to grasp difficult concepts is the mark of a great teacher, you sir are a fabulous teacher. Thank you.
(1:45) The much more simple solution to that question is: Because (a) matter is equally distributed on a global scale, (b) matter on cosmic scale is extremely thinly distributed, so that "friction" (or "collision"), which is the necessary precondition of "clumping", does happen only on a tremendously rare scale, and (c) all non-clumping matter settles in rotation systems, because those rotation systems always constitute stable systems for those non-clumping matter.
As far as those conditions apply (and they do), EVEN IF something like galaxy intermingling takes place, you do never end up with "one big chunk of blob", but instead always with rotation systems that look principally not other than the ones before the intermingling. Occasionally you get bigger black holes in the center of those intermingling, but that's, too, extremely scarce.
You do not need any wild dark energy or such nonsense. Just plain simple newton mechanics and a little feeling for the extreme thinness of outer space.
(18:30) The same goes for the "hubbles law": What this is stipulating is only applying in the case of a completely static universe - except for radial movement, and even that only in case of radial movement AGAINST OUR SELF (earth centric world model - in case that's something known to you). As soon as you assume a world model of rotating structures beyond galaxy level, the dependency of cepheid candles to red shifts can equally well stem from relative movements in those rotation systems.
i didn't here or read of anyone ever in the last 50 years of my life who had dared to try ANY other model than the geocentric "everything expends away from earth" model.
Thanks for this. It seems like everyone assuming matter has to distribute a certain way is missing something.
But if the center of mass of rotation for distant galaxies is not moving away, then why would the speed of rotation away from earth increase. If galaxies are rotating around a hypothetical earth center, then that would be at right angles to the earth center and not produce any Doppler shift at all.
@@AllanAngusADA There is a kind of "sticky thinking" in your argument: Since you clamp on the model of "exclusive radial movement from earth" (arguing "why should the speed ... AWAY FROM earth"), you are not able to even consider arguments for other kind of models.
The priests of the inquisition 500 years ago will also have questioned the "new model" in that type of argumentation: Why should we put the sun in the middle when she is clearly visible perfectly rotating around earth?!"
You should go on a ride with a turntable together with some other guys, do NOT place yourself exactly in the center, and then let the guys throw little stones at you, then protocol the velocities and directions of the incoming stones!
You can, as well, write a little emulation to do the trick for you - if you are able to write programs.
Report back as soon as you have the results!
@ I think you miss the point about the expansion of space overall. All distances expand between any two points. The absolute rate of expansion is higher for the larger distances. This is not at all centered on Earth or any point. There is no center point nor any rotation which would violate conservation of angular momentum if there were no rotation showing in the CMBE.
@@AllanAngusADA The term "All distances expand between any two points" does stipulate nothing about where we (earth) position ourselves in the "observable universe". What produces that latter stipulation, however, is the stipulation that the observable universe is surrounding us to all directions in the exact same mannor, and that this observable universe shall end at about 14*10^9 ly distance. These two terms together force the stipulation of earth being in the absolute center of the whole thing. Else, you would be required to watch differences for any opposing vectors. What you do not - according to publications of observations so far.
That's the current "accepted" model. And is gets confronted with a daily growing amount of discrepancies. We are at a point where what we see is not what our models according to those "accepted" theories predict.
That is a mirror of the situation around 1500, when Kopernikus and Gallileo (and a bunch of other less known colleges of their time) challenged the old "accepted model" of the european church.
What the defenders of the old "accepted" model did, was to add more and more specific appendices to their old model to make it fit the newer observations to be able to clamp on it just a little longer, until the next better observations stumbled in.
That, too, is a mirror of the current situation in astrophysics.
Good luck with that policy! :D
The difference between charlatanry and science is, that science can make predictions that hold - for eternity. Newtons laws of gravitation and mechanics hold up to the current day: You can perfectly well calculate motions of objects in our solar system forward and backward in time based on those laws and you will end up with predictions that HOLD - to the accuracy of the measurements at the start of the calculation. THAT is science.
Literally EVERY DETAIL that got predicted for the distance at about 13*10^9 ly away based on the best of "adjustments" of the "currently accepted model" just 20 years ago gets contradicted by literally every observation that comes in from the James Webb Telescope. With literally EVERY single observation, you can read about "contradictions" and "new adjustments" to what those idiots think about how their model could possibly work despite all that shit. That is charlatanry.
Amazingly intutive explanation on parallax, damn nice
Absolute Cinema
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Hi Mahesh , the way you make videos is so nice. After working whole day. It feels so nice to watch ur video
i’ve been so excited for this video. the expanding universe and dark energy is such an enigma to me
So they capitalized on parallax error to actually obtain real useful data, that is so cool, i did not know this thank you!
Parallax is way to measure distances all by itself. Just that it has a much smaller range compared to cepheids.
Can you make a video about this:
Times moves slower in moving objects.
If Tom travels away from Claire at 0.99c and then returns he would have aged slower. But why?
If you look at it from Toms perspective Claire is the one thats moving. Him accelerating could be seen as him decelerating. Who did age more when they meet again?
Amazing video! Thanks !
i really love float head physics and i wait everyday please we need more videos . love for india pune
Finally bro is back after hearing scientist conversation....
Mahesh Sir, could you please bring that informative video on dark matter and dark energy? It presents some recent and groundbreaking findings that shed light on these intriguing subjects, and I believe it will greatly enhance our understanding of the universe!
Quran 51:47
"We built the universe with ˹great˺ might, and We are certainly expanding it."
How could a book 1400 years ago contain the recent discoveries?
There are many more
Quran 21:30
"Do the disbelievers not realize that the heavens and earth were ˹once˺ one mass then We split them apart? And We created from water every living thing. Will they not then believe?"
Although I knew many facts, I really enjoyed watching your video, thank you! If you ever get bored of expaining fully accepted theories, I‘d be very keen to see how you would explain / discuss Roger Penrose’ conformal cyclic cosmology / CCC theory to a broader audience here in your channel.
I find it very convincing, even when it is still a not yet prooven theory.
Great work Mahesh, keep it up, i alawys wait for your vidoes..
It might be overkill, but when it comes time for me to drink the remaining milk from my bowl of cereal, I always pause the video to make sure I don't miss anything.
On the topic of Big Bang, can you please make a video on cosmological inflation? How is it even physically possible? Or is there anything we are still missing and cosmological inflation is just a "placeholder" theory until we get the real picture?
Hubble was a lawyer not a liar turned astronomer 😊
Most excellent presentation. I enjoyed it immensely ! You do wonderful work.
21:23 What I never understood: Is the expansion of the universe associated with Dark Energy or is it the acceleration expansion of the universe?
Dark energy in theory is the cause of the aceleration of the expansion of the universe, it has never been proved existince but its believe to, because in einstiens theorys the universe should already be shrinking because of the gravity of mass objects of the universe but thats not what observed, but it could more be that the expantion of the universe just a ilusion from our small observible part of the universe because of a hyperbolic form of the universe
Hey Mahesh can you please make a video explaining the most fundamental particles (fermions and bosons) and how they interact with each other for formation of matter?❤
I could be wrong, but didnt recent research show the observed expansion to be an illusion of a non-uniformly densed universe? Which causes the light to be red shifted in large portions of empty space
This is true education! Thank you for your enthusiasm and dedication.
amazing video man keep it up
Hi i really liked this video, for a while i have been hooked on your videos and wait for them to release, i was wondering where do you generally learn about stuff like this?
I think you can get a lot of information online - websites, articles, and even books.
A very enjoyable and informative talk. Thanks.
Hi Mahesh, would you consider doing a video on Timescapes? It seems interesting, but I feel like you are the only person who can possibly articulate it for a layman like me. Thanks for all that you do!
Hey, thanks. Yes that’s the next part.
@@Mahesh_Shenoy I am so sorry! I missed the ending of the video where you mentioned the steady state universe. Thank you so much Mahesh, you are amazing! :)
You are the master of the segue for the adverts...
Really thanks for sharing your knowledge to us ❤❤❤❤❤❤
My favorite channel. TH-cam or anywhere else.
Amazing video ❤
Love your videossssssssss>>>>>>>>>
Hi mahesh i am searching for a good textbook for chemistry ,please do let me know if you have any recommendations
Hi mahesh, i’ve never understood magnets in physic. Could you makea video about them and about what makes a piece of metal a magnet and which is the mechanism that makes a magnet attract other body? (Maybe you’ve already made this kind of video, if you’ve done it, i apologize)
one of the best video on this topic❤❤
I love you physics
1:25 But the "Shell Theorem" states that a spherical shell has no gravity inside.
So at any location, a homogeneous universe (being made of a sequence of enclosing spherical shells) has no force to make things clump together.
So Newton's answer would be that the Universe would not collapse, would be stable.
(Just search for the Shell theorem)
خیلی خوب توضیح میدی👍👍👍
when does the 2nd part drop?
Was it discussed here how they calculated to get “true brightness” from the relationship between “apparent peak brightness” vs “period”? Or was that calculation skipped here? Where in the video was it explained if I missed it.
Thanks Mahesh for making such content. This video makes me wonder that can a star transition from one galaxy to other or it’s not possible because of the expanding galaxies?
Individual stars can't really "transition" between galaxies, but they can be ejected say when they are part of a three body system!
A wonderful teacher!
or is it???
... or _IS IT_ ???
Hey Plz make Part 2 also
Hiii nice video n if possible can u make a video on Big bang in a much more detailed way like is it the beginning of time, could there be manny Big bangs n ours is just one of them? Etc
1912 Slipher discovered galaxies. I thought you would mention it was 1912. I think that is a nice historical detail !
Very excellent. I love the shirt.
Do you have a video explaining how redshift is measured? How do we know that the light is redshifted, as opposed to just starting out more red?
One way is to look at their spectra. Elements like H and He have characteristic absorption frequencies (they'll appear as black bands in the visible spectrum). Those bands will be shifted toward the infrared if the star is moving away.
Thank you 🙏🏻 ❤
Always when I hear something was incredible, I'm thinking:
"Oh, so it has low credibility?"
What was there before the Big Bang ?
Hubble said that redshifts also could mean earth is in the center of the universe (observational approach to cosmology book) and that they think that option is horrific, Stephen Hawkings said in "grounds of modesty" they don't want to choose the earth centered paradigm.
General relativity allows earth to be at center of universe, is just a different coordinate system, in einstein's own words.
Geocentricism is better then current model system in explaining the sky, it does not require dark matter and dark energy to make it "work" as big bang model does (and nobody even knows what DM/DE are {nothing more than mathemagic trickery}). Parallax and aberration are also explained in geocentrism as well!
MMX experiment proves earth does not move around the sun, Michaelson gale Proves sidereal rotation of the universe.
Watch the principle from 2014
I've often wondered if, rather than the universe expanding, could interstellar dust be the cause of the red shift we observe. Just as the sun appears redder as the light cuts through more atmosphere at sunset, could light from distanct galaxies similarly be affected?
We treat space as a perfect vacuum, but there is some matter floating out there, and over a great enough distance, like the distance between galaxies, could have a compound effect? The more distance the galaxy, the more stuff in-between, hence the greater the red shift.
I'm no astrophysicist and probably don't know enough about optics, so my conjecture has probably already been taken into account and thoroughly debunked.
Bro literally added historical context to a lot of things I already knew but I feel like I learned a lot more.
Like, Leavitt's Law is no longer talked about probably because now Hubble's Law can be used to measure distances and you no longer need to find a Cephied variable star (Idk. I'm not an astro physics guy, just guessing.)... But it is an indisputable fact that Hubble could only discover his law because of Leavitt's law
Yeah... History makes science education a lot easier
Ur Contents are Amazingly Very Beautiful And Wonder Ful Sir U put Things in so much Simple Words I like ur Way of Teaching sir .
Your T-shirts are epic bro lol
Does it say "don't be a jerk"? Isn't jerk the derivative of acceleration?
@minimo3631 yeah it's the acceleration of acceleration lol, basically
@
No that would be speedy acceleration. Acceleration of acceleration basically is d^4x/dt^4 or as Jennifer Coolidge said in Legally Blonde: Snap!
@smart3go o u is right lol took it a step too far 😁 ty
Please explain how true brightness of measurable distance cepheid helpful in measuring the true brightness of longer distanced cepheid?
Your passion is unmatched! Immediately my new favorite science communicator.
Terrific !