The Cosmic Illusion No One Talks About
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- Опубликовано: 2 июл 2024
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At about 9.6 billion light years, our intuition about angular diameter breaks down. Galaxies start getting larger the more distant they are. Let's find out why.
Nick Lucid - Host/Writer/Editor/Animator
Natalie Wells - Researcher
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The Speed of Light is Infinite... Kind Of:
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TIME CODES
00:00 Cold Open
00:28 What is Angular Diameter?
01:56 Angular Diameter Turnaround
02:52 Finite Speed of Light
04:07 Time is a Major Factor
06:02 Space is Expanding
07:48 Cosmic Light Cone
08:21 Summary
09:09 Sponsor Message
10:07 Outro
10:26 Featured Comment
![ian - Fit Check (Feat. VonOff1700) [Official Music Video]](http://i.ytimg.com/vi/sDGWDBg45Dw/mqdefault.jpg)
Wow, I'd consider myself a long time cosmology and astrophysics casual-learner and I've never actually known this was a thing - you're right that no one talks about it. It's always fascinating to learn something entirely new
I'm not sure why barely anyone talks about this. Maybe because the information can't be used to solve any problems cosmologists are facing, so they see it as unimportant? I don't know.
Makes me wonder whether the CMBR that we detect is actually ultra-zoomed-in relative to nearby galaxies. Could that be true? What might we see instead if the CMBR weren't so zoomed-in?
@@ScienceAsylum I agree, topics that don't seem to address current issues or popular topics don't get much funding an any field. I quit studying particle physics when it became apparent I would be chasing grants for the rest of my life. I joined the dark side and became an engineer instead!
And he did a fantastic job teaching it. It’s the first time I’ve heard of this.
@@ScienceAsylum It kind of sounds like you were saying it's not seen as having a practical application. Coming from someone who doesn't really understand the application of cosmology, isn't it all about understanding how the universe works, (or worked rather 😉)? Is this something that you have to get an intuition for as a cosmologist so maybe it doesn't get talked about because it feels intuitive?
It's been a while since a video blew my mind without giving me a migraine. Thanks Nick.
Insanely helpful visualizations. I'm trying to wiggle my fingers so hard right now.
I was about to write the exact same thing word by word(may be not the migraine).
you didn't tell about the taj mahal
I’m using this video to brain wash the people I love 💗
Spot on review
Great video. I've learned some cosmology, but I never considered this effect before. The spacetime diagrams are especially helpful.
Same... I didn't see that twist coming! So now I'm wondering, how far away was the CMB light when it was emitted?
It was everywhere, including here.
@@nate5land No I mean the light reaching us today
When you don't know that you don't know, of course you never considered it.
@@peterburgess9735 The plasma that emitted the CMB we're currently receiving today? It was (roughly) 40 _million_ lightyears away when it emitted that CMB. What that plasma ultimately became (i.e. a bunch of distant galaxies) is now 46.5 _billion_ lightyears away. However, the CMB itself has only traveled 13.8 _billion_ lightyears since it was emitted. Expanding space is weird.
The comments really show you hit the nail on the head with the topic choice. I've never heard or seen about this effect while it's mind bending. No other Phys channel i follow mentioned it. The amount of comments sharing the same sentiment just show how underrated this effect is. Kudos. And super big props for openly admitting all the shortcuts and omissions. Chapeau bas dear sir.
Its a Light Drop
Nice one nice one
Light tear? Light teardrop?
@@shoam2103 yep
Light to decent drop
Regardless of the name, we can all agree that it’s a “tear” in the space-time continuum.
Looks like a Light "Teardrop" to me. And dang. Space gets weirder and more confusing the more I learn about it. It hurts my brain. In a good way. There's so many cases where we taking 'seeing' for granted. Both in distant space and the quantum level.
Thanks for all the great content!
Yeah, there's a lot of "figuring out" to do after we get cosmological data before we can actually make sense of it.
@@ScienceAsylum when is your next video coming .
What I was thinking too - 100% a teardrop shape
@@omwalia4475 he just released this one. Be patient.
We can make it look like a normal past light cone, though, if we use , instead, a conformal spacetime diagram.
Usually, when something blows my mind, it takes some time and further researching to understand it. Somehow, you managed to blow my mind and make me understand the issue at the same time.. Kudos.
Even though I'm interested in astronomy an cosmology since decades I learned something astounding today. Thank you Nick!
Me too
Please explain why spiral mirrors when used with a radiometer, allows us to observe Alcione in the Pleiades where it is currently compared with observation of light. This has been published in a couple of abstracts. What is special about a spiral mirror? Do they detect tachyons?
That appears to be a plausible explanation. What are your thoughts?
Even though I know all these concepts and how it works basically, it still amazes me that even observing a single image has all these many factors impacting it.
Still, there is always some great content from this channel. Thumbs up.
Yeah Sheldon, it is amazing.
Dayum!! We got a Einstein reincarnate over here.
Yes indeed
Amazing work, as always! As for the shape, in Brazil we have a chicken snack called "coxinha", which is fried. It has a potatoey carb, and ground chicken breast.
It is delicious. Be sure to have one if you ever spend vacations here hahah
I've been hearing this. The resemblance is uncanny! Even my digital texture matches 😮
These days it’s not perceived as special anymore to access science channels like this when being able to watch 100 of channels that are competing with each other. But I’m
amazed by your way of presenting and explaining topics like this. Completely free and without self promoting. Thank you.
I've never heard of that and trust me, i watch tons of content in cosmology and physics.
You did a very good job at explaining it, this channel really shines on many levels.
all my respect!
Angular diameter turnaround.
I just love the way u explain anything using spacetime Diagram ❤️
It's Super Useful to understand counterintuitive things intuitively
I don't know how anyone understands anything in relativity (or QFT) without a spacetime diagram.
Oh Lucid... QFT, the cool part is couplings and the deltas, the transients and renormalisation so no infinity 😈🖖
@@ScienceAsylum wow had no idea that QFT uses spacetime diagrams, would love to see that in s video!
@@localverse Yep! Feynman diagrams are (secretly) spacetime diagrams.
I love how almost every video I watch of yours I think, "oh no I'm not going to understand this" and somehow you explain it so that I do. I haven't been notified of your videos in a while so I need to keep a lookout.
I would call it a teardrop shape. I knew about the lightcone and that early expansion was faster than lightspeed but I had never put the two concepts together before to get this turnabout point. The universe gets weirder every day.
Same
Its called an ogive. In architecture its known as a gothic arch.
@@soaringeagle5418 nah that shape shown is very different from an ogive. It's a teardrop.
@@SolidSiren By definition teardrop shape is an ogive.
Wow...thanks Nick.
The thing that made it click for me was realising that at 8:51 the overly-large past galaxies at the bottom of the 'teardrop' were closer, on the horizontal axis, to the vertical line running up the centre with the Earth on it... and it makes me smile realising that for the bottom 2/3rds of that light'cone' the Earth doesn't even exist yet and I sub-in the term 'closer to the _Milky way'_ rather than 'closer to _us'_ .
Brilliant explanation, thanks again.
Glad the visual helped 🤓
You gave enough clues at the beginning that I figured out it's because of expansion by 3:30. I definitely didn't expect the effect to be big enough to make distant galaxies appear to be the same size as close ones. Amazing. Thank you!
Mind=blown. Great video, Nick. I haven't enjoyed my mind getting stretched so well since I took quantum physics 30 years ago. Thanks for the wonderful work.
Wow just wow. Never knew this was a problem. But the way you explained it with one small digestible fact at a time to bring it all together was really amazing 👏
Not an easy concept to explain - really well done, Mr Lucid.
I've never heard of this angular diameter effect before, so you not only introduced a new detail (to me) but I understood the 'why' of it in less than eleven minutes! Kudos.
XKCD did a comic about this effect, and I'm glad that finally someone on YT talks about it.
So if I understand earth's past light teardrop correctly, the reason distant equal-sized objects appear larger the more distant they are from us is this: we're seeing them when they were closer, and closer objects appear larger. And we may not be able to see the most distant objects for the same reason we can't see our own galaxy: we are (were?) inside them! And the big bang happened right here, a long time ago. Pretty cool stuff!
Great video! I’ve read papers on this but your clear way of explaining makes it very vivid and simple! Great work as always!
Taken something I never knew anything about and helped me understand everything I need to know for a basic grasp on it. Well done on this.
“Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.”
― Douglas Adams, The Hitchhiker's Guide to the Galaxy
I assume you saw the Hitchhiker image in the background when he referenced this. 🙂
@@johnbennett1465 I was actually just listening mostly as I was doing other things, but any time I hear the words space and big, I automatically think HHGTTG.
I've followed cosmology as an amateur for 40 years. All the pieces you put together such as light-cones and expanding universe, I'm familiar with those. This particular implication, based on how these things work together? This is new to me. Thank you!
I like this, and its very well delivered. And I definitely didn't think about this before! Its really nice to hit on topics that feel fresh!
Been a watcher for so many years still learn something new regularly
It's been quite some time since an educational video literally blew my mind🤯 your explanation is sooo good I mean you clearly connected the dots by mentioning each point one after the other...
Awesome! Thank you! I had often tried to think of how light was affected from an expanding early universe. I knew it wouldn't be straight forward, but I could never really visualize it. (Of course I never tried to, you know, actually research it either. ) This was a great visualization.
Yes, however, why hasn't Orion's belt become fatter? Also, why where they able to use stars to navigate for thousands of years. That's thousands of light years, this should have made that impossible if space is expanding at such a rapid pace. This video gives me more questions than answers, sorry that I choose you to ask, but care to take a stab?
@@GrandKai9 If you don't mind my butting in, all the stars we can see are in our region of our galaxy, the Milky Way, and the stars in our galaxy will never recede from us. Also, none of the galaxies in our galactic cluster, the Local Cluster will ever recede from us due to cosmological expansion.
The stars do move in their individual orbits around the center of the Milky Way, but so slowly (in angular dimension) that it takes thousands of years for the constellations (like the Big Dipper) to change their shapes.
@@numbersix8919 Thank you so much for your input, I was honestly just looking for anyone to explain, because I knew I was wrong somewhere and didn't even know where to begin to look into it.
However, from your answer, I have another question, and if you don't mind me asking. wouldn't the consultations only change as we enter into the accelerated orbit of the center of our galaxy? What I mean is we will be accelerated and tossed to the other side of a very large black hole, in theory, so wouldn't the light that we see instantly be affected? I mean we orbit every 200 to 350 million years, but I would have to assume that would hugely affect our view of the cosmos.
@@numbersix8919 Technically they will recede away eventually, but it will take a really long time. Much longer than universe has existed so far. Scientists are now debating if the recession will eventually mean the Earth will be alone in dead, black space or its forces will overcome even that (big rip) and individual atoms will be all that is left...
@@GrandKai9 And to answer your question, thousands of LY is nothing on the scale of expansion. It is 'rapid' when measured on a scale of millions to billions of LY, trying to measure it to Orion's Belt would be like you checking if your cup of tea moved away from you by 0.0001 millimeter.
I am an astrophysics student. My mind blew off when I first came across this. I immediately thought that if I'm getting this right, how come I haven't heard anyone talk about it. You put a very apt title to the video. Good job. 🌹
I followed the idea, that space is dragging light along with it and that produces the tear drop shape and the fact that really distant objects start to look bigger.
But I missed on the geometry. Why does the tear drop shape the galaxies to look bigger? I could use another diagram showing the size increase.
Really nice video! It's amazing how much I learn from you. And now I'll wait for Veritasium to remake this with half as much understanding, some experiment gimmick and more arrogance without crediting you.
Finally someone made a video about this topic that has been on my head since I took extragalactic astronomy 3 years ago.
Nice!
Glad I could deliver 🤓
Jaw dropping as usual. Why would anyone not share this so often today? It's relevant in every way. Thanks man.
"Images of the distant past filled with illusions of cosmic proportion." A beautiful summary for a great video, this one felt as profound to me as your circuit energy video (among others).
I’ve been thinking and wondering about these phenomena very recently and the explanations herein have begun to satiate my curiosity, and for that I thank you.
Glad I could help 🤓
Great job, Nick! I learn so much from you!
Hey Nick, I just discovered your channel and I watched all of your 100+ videos (a little crazy, but now I know that's ok). Thank you for explaining complicated problems in simple terms and for all the simulations you make, they help a lot. Until now I didn't really understand how we could observe galaxies as they were billions of years ago. And I learned more than that, great job! I hope one day you get to use metric units in your everyday life, though my American friends think it's too late now. Good luck to you and all your clones ;)
Thanks! Glad you like my work. I would _love_ to switch to metric here, but I don't think it'll ever happen.
The title says it all. Thanks for making it visually easy to grasp.
And without referring to that non-luminiferous, I mean, dark something or rather.
Fantastic video, it made my Saturday! Your channel helped inspire me to peruse a physics degree, so thank you for all the incredible content and showing me to the subject which I enjoy more than any other
That's great! Good luck!
Nice! You often hear about redshift but very rarely about how the expansion of the universe effects light as its traveling.
Good one, I really learned something today that I never would have thought of before, but it makes perfect sense! Thanks again, Nick!
I love this video so much much, not only because it's amazing but also because all concept talked about in it (like light cones, the expansion of space faster than light, ) I already knew about but they all ties in each other to form something I had no idea about. And that's so cool to me
I love this channel - super informative and great sense of humor : D
This is by far one of the greatest science video's on RUclips. Some people might think observing is just looking. But what do you really see?
I wish this had been longer and more in depth! This is fascinating. Really, not many people talk about this, I've never heard it mentioned!
That was an awesome video and as always 'Lucidly' explained, Thanks Nick!!🙂
And I thought the different horizons were complicated. My mind is officially blown 🤯
I'd heard of this, but never believed it. Thanks for the clear and thorough explanation.
Glad I could clear things up 🤓
I do appreciate how this video explains why we think the universe is expanding, more than just waving around redshift as the cause.
Man, this was great! It brought together a lot of ideas I understand, or thought I did, in a way that puts all of the puzzle pieces together! Impressive!
I used to always ponder about how energy is Mass and now I ponder about the role time plays and how wave-like matter can be, I saw an image of a rock that had been weathered by the wind over centuries or more and the image made it seem as if the Wind and The Rock where a still photo of fluid dynamics at play. I don't know what this means, but videos like yours help me pursue it even more and discover even more fun insights so thank you. I never went to college and this is what I've always wanted to check out 🙌🏿🙏🏿😄
Shout out to text to speech for reminding me that "The Rock" is a force of nature as well*
Hi have a look at Jon Levi on YTUBE , there are two , this one shows pics of old rocks buildings etc m unmissable ,will have you questioning our give history timelines,
7:54 if you were Brazilian you would know EXACTLY what to call that shape: that is an unmistakable COXINHA. Even the color is spot-on
That's true
This is pretty incredible. It's something I never thought about, still don't completely understand, but also somehow makes sense in light of this explanation.
Cool video. 🤘
Great episode. Definitely need to watch it again in order to be able to tell someone else about it.
I had seen this "cone/Taj Mahal" diagram before but today I understood it 😁.
They doing some great math work to build that illusion into the Taj Mahal by making the minarets (the outside structures) at a angle so they appear to go straight up at a distance. I assume people had noticed the towers seaming to lean at a distance in other structures before this.
I like videos like this that explain how we solve problems that seem impossible to solve. Also, on the subject of judging distance, humans also use our binocular vision which can be tricked with things like magic eye pictures.
3:25 loved the Adam Douglas Easter egg!
I guessed this was the case as soon as I heard that galaxies get bigger the further they are after a certain distance. Good video. Have never thought of this before.
If we could see all the way to the Big Bang, there would be a single dot that fills the entire sky. That always freaked me out. Love this video. First time I've ever seen this unintuitive result addressed.
*"...there would be a single dot that fills the entire sky. "*
I've never thought about it that way 😱
That single dot is cosmic microwave background.
@@rockets4kids Nah, that's hundreds of millions of years in front of a potential singularity point that's stretched all around.
Awesome video Nick, it reminds me more of your videos from earlier times. Please make a video on quantum locality and the Nobel prize for 2022. PBS made a video as well but maybe you can dumb it down for us a bit.
As I was editing this, I was feeling the same way. It felt a bit like the olden days.
As for the Nobel, I made a video about entanglement earlier this year: ruclips.net/video/hiyKxhETXd8/видео.html I don't think I have any more to say about it at the moment.
@@ScienceAsylum Sir, thank you Sir!
Wow, this is the most interesting thing I learnt that I have never ever seen or heard in any space documentary or even a youtube astrophysics channel video. Amazing.
I love how you teach me things I didn't even know I wanted to learn.
My mind is officially blown. You're dead right that no-one talks about this! I've been following science as a lay person for decades, and this is the first time I've heard of the phenomenon.
welcome back bro - happy to see your new video .. always a delight 😇😇😇 .. Love from India (BTW maybe second or third or fourth - missed by a Pico second 🤣 or it took a diagonal path for ur video to reach india -D~universal~delay)
You are third 👍. Not bad.
It's amazing the way you can explain such a complicated matter so easily
You've done it again Nick! Mind blown by something I've not come across before! Well done 😊
Thanks!
Super video - although I've attended some basic cosmology courses, I didn't actually know about the angular diameter turnaround. Makes sense though - especially from the clear way you explain it!
This was PERFECTLY explained. These visuals and graphs were amazing. And I would call the past light cone The Past Lemongrab cone.
Fascinating! I never seem to learn anything new from videos about the cosmos, but in this case I did and whats so interesting is that not only was this phenomena unknown to me it represents a tangible proof of the big bang itself, you're actually looking at evidence of it. Well done indeed, a really great video, thank you!
Awesome !!!, I thought I was reasonably educated but this was totally new to me, I really like learning new stuff, many thanks.
That shape resembles quite a lot the Brazilian snack "coxinha" (which means "little thigh" as it supposedly was meant to resemble a chicken drumstick). Thus, I name it, the time coxinha!
Oh wow! The resemblance is uncanny! Even my digital texture matches 😮
@@ScienceAsylum IT'S A COXINHA!!!!!!!!!!!!
I'm brazilian and I was searching for this comment. The shape made me remember a coxinha too lol.
Angular Diameter Turnaround Point. That does blow my mind, literally. Why isn't this plastered all over cosmology discourse? I feel like I've been imagining the universe wrong until now where every object fades in optical diameter as it recedes into the distance. Everything starts to come closer, that is crazy,!! Thank you for sharing this and all the great new-to-me terms. I think it's a huge thing to know.
🤷♂️ I'm not sure why barely anyone talks about this. Maybe because the information can't be used to solve any problems cosmologists are facing, so they see it as unimportant? I don't know.
Amazing. Visuals and explanations are on point!. Thank you.
This is something I didn't know that I didn't know and didn't know that I would love so much!
Thanks again Nick👍
You're welcome 👍
Ah yes. Another quirk of living in a 4D universe.
oh yeah, there's xkcd comic about that!
Yep... and that XKCD comic was inspired by a Twitter post from Katie Mack.
Thank you Nick, and thank you Question Clone! Question Clone is awesome. This was an amazingly detailed, but not scary, explanation of an interesting phenomenon!
It has always bothered me that no one talks about this issue. Thanks for changing that.
👍
Oh wow this is SUCH a cool concept that so many other astrophysics channels haven't even talked about yet!
True, first time anyone has pointed that out. Nick often picks up science-ed topics first.
I guess the real brainbreaker is realizing that any object (in the loosest sense, particles, waves, etc) can only move a lightspeed, while space is not limited by such constraints. I really love these seemingly ADHD fueled explanation, they just tickle my brain at the right buttons.
Space is also limited by those constraints... locally. It's the cummulative effect of many tiny and relatively slow stretchings of local space which causes the overall space/Universe to expand faster than light.
That also happens with other peculiar situations like when you (theoretically) point a super laser at the moon and move it around: the (again theoretical) "object" (reflection) that your laser makes on the Moon's surface can perfectly move faster than light... but it's not any real object, it's just an effect.
You did great job explaining, the last diagram showing the tear drop shape still showed the red shift, that helped visualize the concept of what you were describing
Thanks for letting me know. Attention to detail (like the redshift) is important to me. It's nice to know it's appreciated.
Very funny and instrutive. It's top. Thanks for the humor and to make the complex easier to understand.
The angular turnaround is the most incredible thing I never knew before watching this video! Thanks!
That last part is truly amazing. Thanks so much for this video!
This kind of videos is really a life saver! Thank you!
7:37 i love the concept of island universes. Being galaxies are exponentially farther apart than star systems within them, that's a mindboggler.
This video is so great!
explained me a totally new concept with such elegance
I love it!
This is crazy! I was totally unaware of this effect. Thank you!
You're welcome!
This was awesome as alwwys. This really blew my mind! Keep up the good work
I have never heard of or considered this! Cool video, thank you.
This was very good! First time i’ve ever heard of it - thanks!
I never thought of this. Amazing. Thanks for explaining it in a way I can understand. Who knew.
Cool video. Your explanations are always my favorite
Nicely presented.
Good instructive and relatable graphics
This is one of my favorite episodes so far. I had to watch it twice.
It's a tear drop.
The science asylum is so sad, but its the only place where i feel safe.
this is an incredible thing to learn about, thanks for sharing!
Omg this totally clears up something i've thought about! I never quite knew how to put it into words, but the universe we see as we look out is a skewed version that only we can see, like we dont see *the* universe as it is *now* we're seeing images based on our perspective
Yeah, there's a lot of "figuring out" to do after we get cosmological data before we can actually make sense of it. Thankfully, cosmologists have that under control 👍