"it's just how far back our knowledge of the Universe goes" - thank you for saying that, you are the first person I have heard to say that instead of the universe is x amount of years old.
stevemonkey6666 😳 Indeed, but saying ‘how far’ implies some form of distance or extent of existence. Using mathematical extrapolation we now consider the existence of the known universe to be 13+ billion years old and still ‘growing up’ . . . !
I mean, the age of our universe is AT LEAST 13.8 billion years old. Back when I was a kid, it was 7-20 billion years old, but now there is a study implying its possibly 26.7 billion year old. Personally, I am quite skeptical on that. We know for a fact that certain processes take less time and I am fairly certain our limit is at 16 billion years old. As that study for the 27 billion year old universe is mainly looking at stars that theoretically could have formed within less time thanks to some quantum shenannigans or theoretically could have survived a big crunch.
I was letting the video play while typing a clever bit about how time dilation in a massive early universe makes the 13.8 billion number nonsensical when just before I finished in the last 30 seconds of the video he said basically that sort of thing. Drats. I was looking forward to typing something clever today.
I love how the "nerdy" version of yourself also works to prevent people from being pedantic in the comments hahaha There's always the smarty ones that just overcomplicate stuff by being way too picky about details I'm pretty sure you do it on purpose too, but I won't tell anyone! Love your stuff!
War Oliv 😖 Hm! ‘smarty ones too picky about details’ . . . ? Remember what happened to Apollo 13, and how ‘smarty ones’ who were ‘very picky’ about details brought the three astronauts back safely to Earth? Those forensic scientists who examine the minutest details in an investigation? Are they ‘nerdy’ in your esteemed (?) opinion? Really!
Do you even understand in what context I said that? This is a science channel that tries explaining science in a way that most people can understand. Trying to simplify a bit while still being accurate IS the point of the channel. That's why he doesn't use too much math, so almost everyone can understand what he's talking about. Context mate, the example you gave is completely different from the point of these amazing videos. Overly detailing stuff isn't bad, in fact it's good. Not in this case though, since he's trying to teach in a way people will understand and stick around, instead of closing video because it is filled with advanced math.
as an engineering student halfway through my curriculum, that simple diagram of the stress energy tensor colored like that just made tensors click for me, so thanks!
"Gravity isn't about mass, it's about energy." Thanks for this. Why can't textbooks just come out and say this? It'd clear up a lot of confusion about photons being massless.
I will avoid the math you 'kind of glazed over' but do wish to thank, thank, thank you for all of your excellent work. Specifically that whole "data vs. results" subplot was HILARIOUS in this episode. 10 out of 10!
I was sceptical when I first came across this channel, but now I really appreciate the content for what it is - science and simple explanations. I guess I'm a little crazy now...
This video, by itself ,deserved an award. You're the best, those who dont know about this channel are missing out on so much. Thanks for answering the biggest query I had eversince I started pondering about astronomy. Thanks a lot sir.
Love your videos. I have a few suggestions for when a clone pops into frame: A. Don't have your actors facing each other directly. Have them point slightly towards us, as it seems to invite the viewer in to the conversation. If they are directly opposing it makes us feel awkward. B. Another idea is to not have a cut at all. Keep your "you" self in frame and have your clone step into frame and ask a question or contest, and step away. Less jarring and slightly more believable without a sudden perspective change.
I appreciate the information you provide, hard to believe, but this kind of information and the way it is explained are not found on other channels. I shake your hand, with respect ! I will share links to your videos everywhere I can, hopefully this will increase the subscribers (1M+) and help you deliver great content like this for as long as possible.
As Einstein said "If you can't explain it simply, you don't understand it well enough" and u make everything simple. please do video on spacetime, if space is expanding so we have to consider time is also expanding but we dont experience time expansion.
This is my favorite answer to this question. We don’t know for sure, this is just how far back the knowledge of the universe goes. Perfect. Another great video! Please don’t ever get rid of that pet monster!!
The Science Asylum My brother and I got them when he was 4 and I was 8. We used to practice pile drivers on him. We gave my brother’s a short hair cut to tell them apart.
Hi Nick. Absolutely love your videos. You are incredible at making very complex subjects understandable to the layman. Been watching through them now from your first to whatever the latest is. Thanks 😊
I love this video. I never say the universe is 13.8 billion years old. I always clarify that based on our knowledge, the universe is roughly that age. I always make sure to state that our knowledge is limited at best, and even based on that, we only use rough estimates to get the 13.8 b
The Science Asylum Just do your best. I think only uploading once or twice a month might actually work to your benefit. Less frequent uploads make each one more exciting. I've noticed lately that I'm more likely to watch a video soon after its uploaded if it's from a channel that uploads less frequently. Keep doing what you're doing. 🙂
when using telescopes to "see the past" how do we know that the conditions and constants of the universe used to be as they are today and that we can even do those extrapolations into the past? how can we rule out other possibilities or the influence of things/processes we can't see today?
the stuff we can see with telescopes is relatively mundane ie. matches the predictions. We rule out other weird possibilities via occam's razor - it's simply more likely that our knowledge about the universe today (and near past) extrapolates into the further past, than the possibility that it just happens to look that way.
Just to add to what KohuGaly said, we do sometimes find that something we thought was constant isn't constant. The "Hubble constant" is a good example, which is why we renamed it the "Hubble parameter."
PLEASE CAN YOU DO VIDEOS ON-1.WHY INTERNAL CONSTITUENTS OF A SYSTEM CANT AFFECT IT EXTERNALLY?( ie a person inside a box cant cause the box to move by hitting against the wall of the box from inside...I think this is also reason why emdrive cant work)2.WHY WE NEED FORCE CARRIER PARTICLES TO DESCRIBE FORCE?3.CAN WE EVER CHANGE THE LAWS OF PHYSICS INTO WHAT WE LIKE?
I was unaware just how much our understanding of time broke down in the first phase of the universe (I knew that questions about what happened before the big bang suffered from this). I took the "age of the "universe" figures quite literally. Thank you for helping to clarify that.
@@zerocool4835 Space time is great and I am a regular viewer, great to meet a fellow fan. Also really loved Infinite Series (a pity that the show couldn't live up to its name). I understood that at the very beginning our understanding of time breaks down at t == 0 (in the same way that the meaning of north and south breaks down at the poles). However, what this video managed to get me to see is that our understanding is still very limited the early stages of the universe for t > 0. This is qualitatively different from our understanding breaking down at the singularity (north is still perfectly meaningful until you reach the north pole).
"I took everything pedantic about myself and I put it into you. What was I _thinking?!"_ 😆 That'd you could answer him once instead of multiple pedantic commenters?
You are so brilliant Sir.If you ever decided to come to my country please make it public .I will at least come to get a glimpse of you .Wishes from Srilanka (South ,,Asia)
only last part i got it.... other things i don't, but i like watching/listening/both things i don't know, especially if someone can make it interesting...
Nice. 13,800,000,000 years is how far back we know. Thank you for clarifying that. As more pieces of the puzzle come together, the puzzle just gets bigger. I guess that is the nature of infinity. P.S. is it ok to keep getting crazier in small increments?
Thanks! According to some RUclips cosmologists the age of the universe is 13.8 billion years. They claim that they know what happened before from conception to the first data. But whatever, good video. I need to watch it a few times on slow speed, though. It goes too fast for me (again).
Hey Nick! I would love to see you create a video about particle interactions inside the nucleus of an atom and, more specifically, the strong nuclear force. What governs it? Also, why are neutrons so unstable outside of the nucleus but not once inside? Love your videos and keep up your great work!
No one ever saw earth core yet we can still know stuff about it. (I suppose you could say that is also speculation but if you go with that logic to extreme everything is only a speculation.)
Yes we speculate stuff about earth's core too, and it is only few thousand kilometers beneath us and there are some observations to be able to speculate about it. What observations do we have to support all the speculations about black holes?
i like the statement that our knowledge of the universe reaches 13.8 billion years into the past. conservation of energy seems to be a valid and prooven assumption. so the stuff the universe is made of, must be a little bit older than 13.8 billion years. crazy....
Considering the age of our star, 13.8 billion years isn't a lot at all. In fact, it feels like we're oddly close to the birth of the universe (or at least the birth of space and time as we know it).
There is one thing that I can't get may head around. It is the fact that time "ticks" more slowly when you measure it close to some heavy body. But in the early universe when there was primordial soup of quarks and gluons the energy density was enormous so shouldn't it slow time flow. I mean that during first Universe epochs the time was running extremely slowly... how do we take it under calculation during while calculating 13,8???
In case of two clocks, one close to a heavy body, one far away, you can keep them there for a while, then bring together and compare what they clocked. So when you see one ticked less, you can say it ticked slower. But in case of early universe we have nothing to compare with, so any amount of seconds that ticked there is all there is, there is no clock that ran faster and we could compare to. It's like watching TV series. We can say "this show has 400 episodes now, and that particular thing happened 321 episodes ago". Even if some episodes were released daily and some others once a month, if you don't have that external clock and can only talk about episodes numbers, if you only measure time in episodes this relative time rate is unobservable and doesn't change anything inside the TV series.
I always have the impression that scientists try in every way to adapt reality to their calculations. They collect some data - which is just the data you can collect and not the data that really matters - and from there they build their equations and try, kind of desperately, to make things fit there. They begin to show signs of scientific schizophrenia and try to reduce the universe itself into a few obscure equations.
We certainly collection some data/observations and build a model around it. But what makes it science is that we then _test_ that model in the real world and try our best to _disprove_ it with new observations and new data. The models that survive that brutal onslaught are the ones we consider our best science.
I prefer the idea that the universe may be older than 13,8. The idea that there was nothing and then the universe happened just doesn't seem to make any sense. Not that the universe is under any obligation to me to make sense. Still for some reason an infinitely old universe makes more sense to me than one that just came to be 13,8 b yrs ago. Since mass can be made from energy it just feels better to me that there was an infinite amount of energy for an infinite amount of time and then 13,8 b yr. ago 'something' happened that made all this energy suddenly change into matter and we call this event the big bang.
1: Was there more than 1 image of the CMB taken? 2: In an ever expanding observable universe and the CMB sitting on the observable universe horizon, wouldn't the CMB image change due to it's movement away from us?
1. The image I show in my videos is a composite image made from multiple smaller images. It was made in 2015 and is the most detailed version made so far. There were less detailed version made previously. 2. The CMB is emitted by matter and that matter does move away from us as the universe expands. However, the CMB light itself is _not_ expanding away from us. It stretched out during the trip though, which is why it's microwave light now. It used to be visible. (You're on the right train of thought though with motion affecting the way we perceive the light. The motion of Earth around the Sun, the Sun around the galactic center, and the galaxy through space all affect the measurements of the CMB. Those have to be removed from the data before we get that image I'm showing.)
"It's how far back out knowledge of the universe goes." So does mean the 13.8b is actually just a _lower limit_ on the age of the universe, i.e. that it could be a lot older but we don't know anything about what it was like back then?
1:07... A very interesting idea. How to you make your clones behave differentially? It is psychological or it is genetic? And how are you making them in the first place? We deserve some answers after so many time!
Quantum mechanics prevents _exact_ copies, so they always come out a little different. ( I gave a teaser of my cloning machine here: ruclips.net/video/a9T26ItpcDA/видео.htmlm21s )
I've got a question You said that all frames are equal in every way and no frame gets a priority over another And also according to Maxwell;all accelerated charged bodies emit radiation. But in the frame of the charged body;it appears to be at rest with respect to itself.Then in this situation; how would it emit radiation???
I've got another question on Einstein's photoelectric equation It states that E(of photon)= work function+kinetic energy of electron. Now work function is in a way binding energy of the free electron which is equal to KE + PE and it implies that it is frame dependent And also the KE of the ejected electrons is also frame dependent The photoelectric equation turns out to be Frame independent(E of photon)=Frame dependent+frame dependent How is this possible??And where is the mistake???
1) I mean that accelerating charges _don't always_ emit light. 2) The flaw in your logic is the energy of a photon is _most definitely_ frame dependent.
How would the age of the universe differ with the change of its typology? Say we missed it bigly and the universe is doughnut shaped while it's so vast, our observable universe is very small that it calculates off the significant error?
If time itself is a "component" of the universe, how is it even logical to call it a property of it...how can we say that the universe has an age if that very thing is contained within it or a part of it??
@@project4200 if I saved up all my farts in a balloon, set the balloon in the middle of a room. You'd be the guy who popped the balloon, and the stuff floating around after the pop.
How can we calculate the age of the Universe by reversing expansion when we only know the size of the observable universe, couldn’t the actual size of the universe be 10 or 100 times bigger? In other words How can we calculate the age of the Universe by reversing expansion when for d=distance you are using the farthest “observable” star or galaxy, couldn’t there be galaxies 10 or 100 times farther away whose light has not reached us yet or never can reach us?
THANK YOU. I've been saying surely the age of the universe has to be older than 13.8B years, because way back when there was a more dense universe, the rate of time would be slower, and as we look back further and further that density increases and the rate of time is slower. So overall we'd need to stretch the age to compensate for slower time back then, meaning that 13.8B number would be a bigger number. Well... you answered this with the statement about pressure of the universe is currently 1, and if we don't factoring in the change of pressure way back when, the age of the universe calculates at 9.7B years. So it turns out the 13.8B number IS the age with the factored in "slower rate of time" back in the past. Thank you! However ... I liked the part where you said, what's before that 13.8B? Could be a fraction of a second, could be a billion years, could be an infinite amount of time! Personally I like the idea there's an infinite amount of time before the point in the universe where we can currently measure to, because it would seem that as we keep forever learning more and more about what was before the point we can currently get to, we'll keep increasing the age of the universe, and over an infinite amount of time, we'll increase the age of the universe infinitely. OK due to heat death we'll be gone before we get there ... but hopefully my point makes sense, but it's just a personal opinion and maybe it was a fraction of a second ... but as pointed out, what did time mean back then anyway?!?!
And what if it isn't? What if it's a great big farce ignoring fundamentals of science? There's some strange, magical one might say, assumptions that that number, what is it? 13 billion? Yeah, OK whatever, that number depends on some maybe something that needs to be there for that number to be calculated. What do they (those, the infamous them) call it? Dark something or other. An invisible, totally unperceptable, completely none observable something they make a number of to calculate the number they need to arrive at. How is that scientific? Is not logical. It's a farce.
Could you talk a bit more about "our concept of time doesn't apply"? How would it look if someone would be there one day after our conceopts starts to apply? Could he then say: 24 hours ago there was no yesterday?
Yep, universe is infinite! We can only calculate as back as when physics decided to be consistent. So that much makes a lot of sense because of entropy. Speaking of which (probably a dumb question, but): does our apprehension of physics apply the SAME to other star clusters / galaxies as well? Or are there slight differences in constants which throw equations off?
I have another question... The universe is 13,8 bilion years old, but the radius of the observable universe is about 47 GLy (caused be the expantion of the universe) ... As I understand it, the expantion of universe is accelerating (or better yet the farther is something away the faster it moves away) and this acceleration is increasing... so there must come, in the future, some critical radius of the observable universe when its boundary will be moving away at the speed of light (so it will be ever impossible to see farther)... how can we calculate this critical radius and if possible, the time (like in bilions of years) when this will happen?
If the Planck Telescope shows the CMB to be homogenous would a more sensitive instrument be able to detect differences in the CMB showing it to be 'lumpy'?
The CMB is _nearly_ homogeneous, but not perfectly. There are bumps and Planck can see them. I did a video all about the CMB recently: ruclips.net/video/Js4Oy2CjOtE/видео.html
Great video Nick, as per usual. I have a question I’d like to ask. It is as follows: We know from special relativity that the passage of time changes with the motion of the observer. So, the 13.8 billion years is the age of the universe as measured by an observer moving with what motion? Is he/she a stationary observer? If so, the observer is stationary with respect to what?
The early universe (pre CMB) is built with particle models. All that existed back then was particles, so time is measured in their reference frame (because it's the only reference frame available).
@@ScienceAsylum Really? I figured that when you factor in special relativity and a bunch of the things in the universe moving at vastly different speeds relative to each other, that some things in the universe would have experienced more time than other things and hence be older. Say for example a bunch of stuff in one region of the universe is moving at 0.5c while in another nearby region a bunch of stuff is moving at a speed of 0.6c or something like that. In general stuff travels at a variety of speeds which should have something to do with time dilation, unless I am missing something.
"it's just how far back our knowledge of the Universe goes" - thank you for saying that, you are the first person I have heard to say that instead of the universe is x amount of years old.
stevemonkey6666 😳 Indeed, but saying ‘how far’ implies some form of distance or extent of existence. Using mathematical extrapolation we now consider the existence of the known universe to be 13+ billion years old and still ‘growing up’ . . . !
I mean, the age of our universe is AT LEAST 13.8 billion years old. Back when I was a kid, it was 7-20 billion years old, but now there is a study implying its possibly 26.7 billion year old.
Personally, I am quite skeptical on that. We know for a fact that certain processes take less time and I am fairly certain our limit is at 16 billion years old. As that study for the 27 billion year old universe is mainly looking at stars that theoretically could have formed within less time thanks to some quantum shenannigans or theoretically could have survived a big crunch.
"13.8 bil years is the time back till which our current knowledge can go"
Nice and exact statement lucid.. awesome work
An alternative reply could've been - "Nick and lucid statement" :)
I was letting the video play while typing a clever bit about how time dilation in a massive early universe makes the 13.8 billion number nonsensical when just before I finished in the last 30 seconds of the video he said basically that sort of thing. Drats. I was looking forward to typing something clever today.
I love how the "nerdy" version of yourself also works to prevent people from being pedantic in the comments hahaha
There's always the smarty ones that just overcomplicate stuff by being way too picky about details
I'm pretty sure you do it on purpose too, but I won't tell anyone! Love your stuff!
War Oliv 😖 Hm! ‘smarty ones too picky about details’ . . . ? Remember what happened to Apollo 13, and how ‘smarty ones’ who were ‘very picky’ about details brought the three astronauts back safely to Earth? Those forensic scientists who examine the minutest details in an investigation? Are they ‘nerdy’ in your esteemed (?) opinion? Really!
Do you even understand in what context I said that? This is a science channel that tries explaining science in a way that most people can understand. Trying to simplify a bit while still being accurate IS the point of the channel. That's why he doesn't use too much math, so almost everyone can understand what he's talking about.
Context mate, the example you gave is completely different from the point of these amazing videos. Overly detailing stuff isn't bad, in fact it's good. Not in this case though, since he's trying to teach in a way people will understand and stick around, instead of closing video because it is filled with advanced math.
"I won't tell anyone"
Well that's been thrown out the window
Actually it was already outside the window to begin with
Lets just hope future astronauts arent using these videos for references. Lol. This guy is great!!!
@@sirmeowthelibrarycat Way to miss the point completely.
as an engineering student halfway through my curriculum, that simple diagram of the stress energy tensor colored like that just made tensors click for me, so thanks!
*Astronomical* video quality as usual.
This channel has been beyond instrumental in helping me develop my first novel. Thank you and keep making more
You're welcome! Glad to help :-)
Appreciate the response! Don't be surprised if I make a character based on you one day :-)
Tactile Therapy Next Dan Brown
Name of the novel! I want to read it once it's out :D
Thanks! Its out now...it's called Tactile Therapy. You can search for it on amazon and itunes. The links are on my page
Best explanation I've seen of the big bang model, you rarely see people being honest about the fuzzier parts for some reason
"Gravity isn't about mass, it's about energy."
Thanks for this. Why can't textbooks just come out and say this? It'd clear up a lot of confusion about photons being massless.
I will avoid the math you 'kind of glazed over' but do wish to thank, thank, thank you for all of your excellent work. Specifically that whole "data vs. results" subplot was HILARIOUS in this episode. 10 out of 10!
I was sceptical when I first came across this channel, but now I really appreciate the content for what it is - science and simple explanations. I guess I'm a little crazy now...
Glad you came around :-)
For what we know it could be infinitely old, it's nice that you clarified that it's only about our current knowledge and not the actual age
Really love the way how you bring up all the problems in a calculations and put up the answers for it too..... that's what makes u the best
So you borrowed a t-shirt from PBS spacetime guy.Its good to see my two favorite channels wearing each others shirts.
Yeah, we exchanged shirts :-) I actually got a chance to talk to him in person a few weeks ago (VidCon), so that was cool.
This video, by itself ,deserved an award. You're the best, those who dont know about this channel are missing out on so much. Thanks for answering the biggest query I had eversince I started pondering about astronomy. Thanks a lot sir.
You're welcome :-)
you're fabulous in explaining even the most difficult thing in cosmology.
I love it when assumptions and ideas that I’ve held for decades are blown away - and, once again you have succeeded to do so! Awesome!
Great overview. It's always nice to have the details and methods behind the "results" we learn. :)
Love your videos. I have a few suggestions for when a clone pops into frame:
A. Don't have your actors facing each other directly. Have them point slightly towards us, as it seems to invite the viewer in to the conversation. If they are directly opposing it makes us feel awkward.
B. Another idea is to not have a cut at all. Keep your "you" self in frame and have your clone step into frame and ask a question or contest, and step away. Less jarring and slightly more believable without a sudden perspective change.
I appreciate the information you provide, hard to believe, but this kind of information and the way it is explained are not found on other channels. I shake your hand, with respect ! I will share links to your videos everywhere I can, hopefully this will increase the subscribers (1M+) and help you deliver great content like this for as long as possible.
Man your vids are amazing!!
This is the first time I am on your channel and I absolutely love your content right away! :)
Just found your channel. Why doesn’t this have more views? More subs? Incredible stuff!!
Thanks! 🤓 (I'm a little weird, which probably doesn't help the channel's growth.)
This channel is criminally underrated.
Nicely explained
Thank you. The best and most reasonable and honest answer to the question.
As Einstein said "If you can't explain it simply, you don't understand it well enough" and u make everything simple. please do video on spacetime, if space is expanding so we have to consider time is also expanding but we dont experience time expansion.
This is my favorite answer to this question. We don’t know for sure, this is just how far back the knowledge of the universe goes. Perfect. Another great video!
Please don’t ever get rid of that pet monster!!
I've had him since I was about 4 years old. He's not going anywhere.
The Science Asylum My brother and I got them when he was 4 and I was 8. We used to practice pile drivers on him. We gave my brother’s a short hair cut to tell them apart.
Your videos are by far the best
Wow, that was complex!!!
I couldn't grasp.
Hi Nick. Absolutely love your videos. You are incredible at making very complex subjects understandable to the layman. Been watching through them now from your first to whatever the latest is. Thanks 😊
Glad you like them 🤓
Good to see your video again .. Its hard to wait for your videos ..please make more more more..Thanks BTW
There was a difficult amount of information in this video for me to follow. Kudos to those who can grasp the concepts here.
Wow. You blew my mind as always :)
Instant like.
I love this video. I never say the universe is 13.8 billion years old. I always clarify that based on our knowledge, the universe is roughly that age. I always make sure to state that our knowledge is limited at best, and even based on that, we only use rough estimates to get the 13.8 b
Loved this explanation! Many thanks! Great work as always (you must do some collabs with other science channels to get the name out)!
Working on a couple collabs right now actually.
Another great video, and thanks for recognizing Data's personhood.
New Science Asylum video! YES!
Really liked the video and how you made the math accessible. Will you ever make a video on tensors? I'm buying your e-book and can't wait to read it.
THE SCIENCE ASYLUM --> Question: Can you do a video about the nature of the Island of Stability?
Another great video with good info
loving your productivity nick :-)
2 videos in 1 month? Great!
That's what I try to make happen every month. I don't always manage it though.
The Science Asylum Just do your best. I think only uploading once or twice a month might actually work to your benefit. Less frequent uploads make each one more exciting. I've noticed lately that I'm more likely to watch a video soon after its uploaded if it's from a channel that uploads less frequently. Keep doing what you're doing. 🙂
How old those videos are?
What happens before the upload?
Where they come from?
Have they always be there?
Yeah right! I will have a look to the maths! Like I would understand it!😂😂😂 I MISSED YOU Nick Lucid from the Science Asylum!🤗 Welcome back!!! ;-)
It’s great that you always point out the “but”.
Fascinating! I like the shot if the data you included
Awesome explanation
when using telescopes to "see the past" how do we know that the conditions and constants of the universe used to be as they are today and that we can even do those extrapolations into the past? how can we rule out other possibilities or the influence of things/processes we can't see today?
the stuff we can see with telescopes is relatively mundane ie. matches the predictions. We rule out other weird possibilities via occam's razor - it's simply more likely that our knowledge about the universe today (and near past) extrapolates into the further past, than the possibility that it just happens to look that way.
Just to add to what KohuGaly said, we do sometimes find that something we thought was constant isn't constant. The "Hubble constant" is a good example, which is why we renamed it the "Hubble parameter."
PLEASE CAN YOU DO VIDEOS ON-1.WHY INTERNAL CONSTITUENTS OF A SYSTEM CANT AFFECT IT EXTERNALLY?( ie a person inside a box cant cause the box to move by hitting against the wall of the box from inside...I think this is also reason why emdrive cant work)2.WHY WE NEED FORCE CARRIER PARTICLES TO DESCRIBE FORCE?3.CAN WE EVER CHANGE THE LAWS OF PHYSICS INTO WHAT WE LIKE?
I was unaware just how much our understanding of time broke down in the first phase of the universe (I knew that questions about what happened before the big bang suffered from this). I took the "age of the "universe" figures quite literally. Thank you for helping to clarify that.
Look up space time start from the first video
@@zerocool4835 Space time is great and I am a regular viewer, great to meet a fellow fan. Also really loved Infinite Series (a pity that the show couldn't live up to its name).
I understood that at the very beginning our understanding of time breaks down at t == 0 (in the same way that the meaning of north and south breaks down at the poles).
However, what this video managed to get me to see is that our understanding is still very limited the early stages of the universe for t > 0. This is qualitatively different from our understanding breaking down at the singularity (north is still perfectly meaningful until you reach the north pole).
How old is the universe? It doesn’t have an age. It has always existed. And It will never end.
Another great video😁, i was thinking about that a lot😆..that was a great explanation, thanks for your hard work))
Doobly doo, made me smile :) Matt Colville also calls the doobly doo that... great video Nick!
Wheezywaiter came up with the word years ago and it spread like crazy.
"I took everything pedantic about myself and I put it into you. What was I _thinking?!"_
😆
That'd you could answer him once instead of multiple pedantic commenters?
You are so brilliant Sir.If you ever decided to come to my country please make it public .I will at least come to get a glimpse of you .Wishes from Srilanka (South ,,Asia)
Btw I love your videos bro...!
only last part i got it.... other things i don't, but i like watching/listening/both things i don't know, especially if someone can make it interesting...
Nice. 13,800,000,000 years is how far back we know. Thank you for clarifying that. As more pieces of the puzzle come together, the puzzle just gets bigger. I guess that is the nature of infinity. P.S. is it ok to keep getting crazier in small increments?
Yes, I think that's OK. I'm not sure we'll ever understand quantum mechanics if we don't.
Me thinks the big bang may be placed correctly. But I also speculate the stuff came from some other place like water gushing forth from a burst pipe.
Incredible video! Well done!
You deserve 13.8 billion views
Thanks! According to some RUclips cosmologists the age of the universe is 13.8 billion years. They claim that they know what happened before from conception to the first data. But whatever, good video. I need to watch it a few times on slow speed, though. It goes too fast for me (again).
Thank you for the another amazing video.
Hey Nick! I would love to see you create a video about particle interactions inside the nucleus of an atom and, more specifically, the strong nuclear force. What governs it? Also, why are neutrons so unstable outside of the nucleus but not once inside? Love your videos and keep up your great work!
Quantum chromodynamics is cool, but complicated. It might be a while before I get to it.
Tell us more about black holes
Here some facts about black holes: No one ever saw a black hole, no one that lives today will see one, anything else about black holes is speculative.
Chike boi you can't see them
No one ever saw earth core yet we can still know stuff about it. (I suppose you could say that is also speculation but if you go with that logic to extreme everything is only a speculation.)
Yes we speculate stuff about earth's core too, and it is only few thousand kilometers beneath us and there are some observations to be able to speculate about it.
What observations do we have to support all the speculations about black holes?
Chike no one has ever seen the earth's core either. we use indirect detection methods of almost everything we have observed
Another great episode!
i like the statement that our knowledge of the universe reaches 13.8 billion years into the past.
conservation of energy seems to be a valid and prooven assumption. so the stuff the universe is made of, must be a little bit older than 13.8 billion years.
crazy....
Thanks for another great video!
Considering the age of our star, 13.8 billion years isn't a lot at all. In fact, it feels like we're oddly close to the birth of the universe (or at least the birth of space and time as we know it).
Yes and, considering how long the universe is supposed to last, it's still pretty young right now.
There is one thing that I can't get may head around. It is the fact that time "ticks" more slowly when you measure it close to some heavy body. But in the early universe when there was primordial soup of quarks and gluons the energy density was enormous so shouldn't it slow time flow. I mean that during first Universe epochs the time was running extremely slowly... how do we take it under calculation during while calculating 13,8???
In case of two clocks, one close to a heavy body, one far away, you can keep them there for a while, then bring together and compare what they clocked. So when you see one ticked less, you can say it ticked slower. But in case of early universe we have nothing to compare with, so any amount of seconds that ticked there is all there is, there is no clock that ran faster and we could compare to.
It's like watching TV series. We can say "this show has 400 episodes now, and that particular thing happened 321 episodes ago". Even if some episodes were released daily and some others once a month, if you don't have that external clock and can only talk about episodes numbers, if you only measure time in episodes this relative time rate is unobservable and doesn't change anything inside the TV series.
thedeemon, that's a great analogy!
Plz make a video on the math of general relativity
I always have the impression that scientists try in every way to adapt reality to their calculations. They collect some data - which is just the data you can collect and not the data that really matters - and from there they build their equations and try, kind of desperately, to make things fit there. They begin to show signs of scientific schizophrenia and try to reduce the universe itself into a few obscure equations.
We certainly collection some data/observations and build a model around it. But what makes it science is that we then _test_ that model in the real world and try our best to _disprove_ it with new observations and new data. The models that survive that brutal onslaught are the ones we consider our best science.
Well explained, as usual. Thanks.
"as the area or our knowledge grows, so too does the perimeter of our ignorance." -Neil deGrasse Tyson
Perfect video. Like always.
I prefer the idea that the universe may be older than 13,8. The idea that there was nothing and then the universe happened just doesn't seem to make any sense. Not that the universe is under any obligation to me to make sense. Still for some reason an infinitely old universe makes more sense to me than one that just came to be 13,8 b yrs ago. Since mass can be made from energy it just feels better to me that there was an infinite amount of energy for an infinite amount of time and then 13,8 b yr. ago 'something' happened that made all this energy suddenly change into matter and we call this event the big bang.
Well done.
1: Was there more than 1 image of the CMB taken?
2: In an ever expanding observable universe and the CMB sitting on the observable universe horizon, wouldn't the CMB image change due to it's movement away from us?
1. The image I show in my videos is a composite image made from multiple smaller images. It was made in 2015 and is the most detailed version made so far. There were less detailed version made previously.
2. The CMB is emitted by matter and that matter does move away from us as the universe expands. However, the CMB light itself is _not_ expanding away from us. It stretched out during the trip though, which is why it's microwave light now. It used to be visible.
(You're on the right train of thought though with motion affecting the way we perceive the light. The motion of Earth around the Sun, the Sun around the galactic center, and the galaxy through space all affect the measurements of the CMB. Those have to be removed from the data before we get that image I'm showing.)
@5:14 Tardis
"It's how far back out knowledge of the universe goes."
So does mean the 13.8b is actually just a _lower limit_ on the age of the universe, i.e. that it could be a lot older but we don't know anything about what it was like back then?
Correct.
Can you please explain all the hipe about graghene and what it might mean for the future?
I liked and licked this episode!
You said “glazed over” when you meant “glossed over”. Glazed over is what our eyes do if you get too detailed on the math (which you don’t really do).
Ah but doesn't causality and thus time require infinite regression, like trying to find the beginning of a circle?
1:07... A very interesting idea. How to you make your clones behave differentially? It is psychological or it is genetic? And how are you making them in the first place? We deserve some answers after so many time!
Quantum mechanics prevents _exact_ copies, so they always come out a little different. ( I gave a teaser of my cloning machine here: ruclips.net/video/a9T26ItpcDA/видео.htmlm21s )
You are just amazing
I've got a question
You said that all frames are equal in every way and no frame gets a priority over another
And also according to Maxwell;all accelerated charged bodies emit radiation.
But in the frame of the charged body;it appears to be at rest with respect to itself.Then in this situation; how would it emit radiation???
Short Answer: The statement "accelerated charges emit light" isn't universally accurate.
I have a video on my to-do list that might help with this.
So you mean that accelerated charges may emit light or something like that???
I've got another question on
Einstein's photoelectric equation
It states that E(of photon)= work function+kinetic energy of electron.
Now work function is in a way binding energy of the free electron which is equal to KE + PE and it implies that it is frame dependent
And also the KE of the ejected electrons is also frame dependent
The photoelectric equation turns out to be
Frame independent(E of photon)=Frame dependent+frame dependent
How is this possible??And where is the mistake???
1) I mean that accelerating charges _don't always_ emit light.
2) The flaw in your logic is the energy of a photon is _most definitely_ frame dependent.
So is it h times f(observed)
How would the age of the universe differ with the change of its typology? Say we missed it bigly and the universe is doughnut shaped while it's so vast, our observable universe is very small that it calculates off the significant error?
That shouldn't affect the number we have all that much, but it would affect the earlier part we don't know about.
Thanks
If time itself is a "component" of the universe, how is it even logical to call it a property of it...how can we say that the universe has an age if that very thing is contained within it or a part of it??
So, is the Universe saying "Its ok to be a little old"? 😂
Ha! 😂
😁
Almost 14, no the Universe is a moody pimply-faced teenager.
f. g your not funny
@@project4200 if I saved up all my farts in a balloon, set the balloon in the middle of a room. You'd be the guy who popped the balloon, and the stuff floating around after the pop.
Bedankt
How can we calculate the age of the Universe by reversing expansion when we only know the size of the observable universe, couldn’t the actual size of the universe be 10 or 100 times bigger?
In other words
How can we calculate the age of the Universe by reversing expansion when for d=distance you are using the farthest “observable” star or galaxy, couldn’t there be galaxies 10 or 100 times farther away whose light has not reached us yet or never can reach us?
The size of the _entire_ universe could easily be infinite, but it doesn't matter. All that matters is the size of the _observable_ universe.
THANK YOU.
I've been saying surely the age of the universe has to be older than 13.8B years, because way back when there was a more dense universe, the rate of time would be slower, and as we look back further and further that density increases and the rate of time is slower. So overall we'd need to stretch the age to compensate for slower time back then, meaning that 13.8B number would be a bigger number.
Well... you answered this with the statement about pressure of the universe is currently 1, and if we don't factoring in the change of pressure way back when, the age of the universe calculates at 9.7B years.
So it turns out the 13.8B number IS the age with the factored in "slower rate of time" back in the past. Thank you!
However ... I liked the part where you said, what's before that 13.8B? Could be a fraction of a second, could be a billion years, could be an infinite amount of time!
Personally I like the idea there's an infinite amount of time before the point in the universe where we can currently measure to, because it would seem that as we keep forever learning more and more about what was before the point we can currently get to, we'll keep increasing the age of the universe, and over an infinite amount of time, we'll increase the age of the universe infinitely.
OK due to heat death we'll be gone before we get there ... but hopefully my point makes sense, but it's just a personal opinion and maybe it was a fraction of a second ... but as pointed out, what did time mean back then anyway?!?!
And what if it isn't? What if it's a great big farce ignoring fundamentals of science? There's some strange, magical one might say, assumptions that that number, what is it? 13 billion? Yeah, OK whatever, that number depends on some maybe something that needs to be there for that number to be calculated. What do they (those, the infamous them) call it? Dark something or other. An invisible, totally unperceptable, completely none observable something they make a number of to calculate the number they need to arrive at. How is that scientific? Is not logical. It's a farce.
Could you talk a bit more about "our concept of time doesn't apply"?
How would it look if someone would be there one day after our conceopts starts to apply? Could he then say: 24 hours ago there was no yesterday?
Yep, universe is infinite! We can only calculate as back as when physics decided to be consistent. So that much makes a lot of sense because of entropy.
Speaking of which (probably a dumb question, but): does our apprehension of physics apply the SAME to other star clusters / galaxies as well? Or are there slight differences in constants which throw equations off?
I have another question... The universe is 13,8 bilion years old, but the radius of the observable universe is about 47 GLy (caused be the expantion of the universe) ... As I understand it, the expantion of universe is accelerating (or better yet the farther is something away the faster it moves away) and this acceleration is increasing... so there must come, in the future, some critical radius of the observable universe when its boundary will be moving away at the speed of light (so it will be ever impossible to see farther)... how can we calculate this critical radius and if possible, the time (like in bilions of years) when this will happen?
There has _always_ been that boundary. It's called the "cosmic horizon." It's the edge of the observable universe.
If the Planck Telescope shows the CMB to be homogenous would a more sensitive instrument be able to detect differences in the CMB showing it to be 'lumpy'?
The CMB is _nearly_ homogeneous, but not perfectly. There are bumps and Planck can see them. I did a video all about the CMB recently: ruclips.net/video/Js4Oy2CjOtE/видео.html
Just one word, "WOOW"!!!
Yay! Another new videos for us crazies!
Great video Nick, as per usual. I have a question I’d like to ask. It is as follows: We know from special relativity that the passage of time changes with the motion of the observer. So, the 13.8 billion years is the age of the universe as measured by an observer moving with what motion? Is he/she a stationary observer? If so, the observer is stationary with respect to what?
The early universe (pre CMB) is built with particle models. All that existed back then was particles, so time is measured in their reference frame (because it's the only reference frame available).
@@ScienceAsylum Really? I figured that when you factor in special relativity and a bunch of the things in the universe moving at vastly different speeds relative to each other, that some things in the universe would have experienced more time than other things and hence be older. Say for example a bunch of stuff in one region of the universe is moving at 0.5c while in another nearby region a bunch of stuff is moving at a speed of 0.6c or something like that. In general stuff travels at a variety of speeds which should have something to do with time dilation, unless I am missing something.