One minor point that I think is interesting nonetheless and which has implications in cosmology. You don't need an edge for resonance, just for waves to be able to "meet themselves". One way for this to happen is for the resonating object to be finite but not bounded. For example the surface of a sphere, considered as a 2D surface, has resonances (spherical harmonics) because a wave can travel around the surface and 'meet' (interact with) itself... it does not need to reflect. This has a very significant application for cosmology. We know very little about the universe at the very beginning of the big bang (just before the inflationary period). Inflation took whatever was happening and 'blew it up' many many many many times. It could be that the part of the universe we see is just a tiny bit of an infinite universe all or part of which was caught up in this inflation. But it is also possible that what expanded was a finite universe with no edge (a higher dimension analog of the 2D surface of a sphere). In that case there might have been harmonics within the early universe, and these would show up as patterns in the cosmic microwave background. Scientists looking for this pattern mostly don't think there is one, hence the general idea that our visible universe is a tiny bit of something much larger (maybe infinite). But there are some tantalizing hints which some scientists think might be traces of just such harmonics in differences in the hotter and cooler areas. We may never know... any pattern is just a glimpse and maybe not enough to say for sure. But the possibility is there, and the idea quite interesting.
I agree, it's why I put up the quick image of the torus as a geometry that could get set up a wave without an edge. :) I felt like going too far into the discussion of boundary conditions would be going into too much detail.
Speaking of waves, what happens to the energy of the photons involved in destructive interference? I have addressed this question quite a few times to Physics teachers and the best answer I have been given (actually, the only answer) is that "our lack of understanding of quantum mechanics makes it difficult to answer this question". As energy cannot be created nor destroyed, the photon's energy must go somewhere, presumably converted into virtual particles or something?
azmanabdula Short answer, dark energy is a complete mystery so far, but there are loads of experiments here on earth trying to find dark matter(it is hoped that it actually interacts with matter weakly). I wouldn't be surprised if we have concrete detection in the next decade.
Dark energy and dark matter are names given to observable phenomenon, the acceleration/speed of the expansion of the universe and the missing matter responsible for the gravity holding galaxies and large bodies together, respectively. As we have little understanding of the origin of gravity it makes sense to me that until we know more about gravity we can't possibly know about dark matter, being even more elusive than gravity/theorised graviton. Dark energy could possibly be the result of the universe travelling through whatever is on the outside of the universe, so some things we may never be able to understand. I enjoy the challenge of contemplation, learning and discovery, and although it can be a very painful process it keeps us motivated and thinking. Having a cake and eating it, would be the stance of a religious mind in my opinion :)
The boundary (of curve space of mass) is gravity field it self. The resonance could be happened (for anything) inside the gravity field. How about that
But would it be possible for two sources of waves to interfere with each other in such a way that for someone looking from the side it would look like a standing wave??
Could 'dark energy' be a quality of space itself? (Struggling to ask this question sensibly - perhaps you could re-word / re-phrase.. in essence i'm just thinking about the nature/elasticity of space as it stretches/expands). I appreciate your work - thank you kindly : )
I have a question regarding measuring intergalactic distances, maybe you can help: [TL:DR If I look at an object from twice as far away it appears half the size. Why can't this method be used to measure the distance to galaxies?] I understand the need for standard candles and red-shift for these measurements, however it only makes sense (to me) when talking about measuring distances to point objects, but galaxies are not points. I'm sure there's some error in my thinking, but; knowing the actual size of the galaxy you're measuring (at least to within an order of magnitude approximation), and knowing the field of view of your telescope in arc seconds, could you not ask "What distance must that galaxy of diameter X be to appear diameter Y in arc seconds in my telescope? For all I know this method *is* used, but I wouldn't exactly call myself ignorant of astronomy, so I'm curious why I've never encountered this reasoning before.
To a certain extent I think that method is used, but problems show up due to the fact that not all galaxies are the same size, and really distant galaxies just look like a point. They are so far away, we can't make out individual stars. (That said, astronomy , particularly observational is not my strong suit.)
Thanks for the reply, I thought this might be the case. What I'm really interested in is comparing this kind of measurement to our red-shift measurements to see if they agree, even if we can only use galaxies near our local group. I have no doubt that the data will agree, but it's another way of testing universal expansion, and who knows, maybe it won't agree, and Hubble's Law may require a different kind of explanation (Light speed increasing with time?). Cheers.
TheResidentSkeptic The sizes of galaxies are indeed one method people try to use to get at distances, but this turns out to be a pretty messy method. The problem is that 1) there is a huge amount of variation in galaxies 2) galaxies in the past were not necessarily the same as they are now, so if you look at very distant galaxies you can't be sure they are like the ones now in size etc. There is a good article on all the different methods astronomers try to use to get at very great distances (including your idea and others) here: spiff.rit.edu/classes/phys240/lectures/distant/distant.html
hi, an old question i've been trying to get an answer to. if i have mass m of matter, and mass m of antimatter, and annihilate them perfectly, does the matter and antimatter cancel, giving e=mc^2, or do the matter and antimatter unravel each other, giving e = 2mc^2?
and, pushing my luck on the number of questions i can ask, can a gravitational wave be trapped inside an event horizon of a black hole? could a black hole therefore resonate internally with gravitational waves?
Why can't things travel faster than the speed of light? Surely if two photons traveled at the speed of light in opposite directions, wouldn't one would be traveling at twice the speed of light away from the other? Isn't speed all relative? Why is there this universal speed limit?
Ok am I the only one who is mesmerized by this dude's eyes lol.. yea he's got dark circles but i'm looking at the color of the iris. Maybe the dark circles accentuate it lmao.. maybe there's some alien DNA there (no offense, most of us have it) Some of these comments are funny as hell tho xD
i thought nuke boxes made water molecules wiggle and jiggle and the friction(?) made that heat up the food and why paper plates don't burst into flames n shit.
But would it be possible for two sources of waves to interfere with each other in such a way that for someone looking from the side it would look like a standing wave??
In a theoretical situation, what would happen if the universe started resonating? ( let's say it had an edge and everything else that is needed?) What are the consequences of that?
One minor point that I think is interesting nonetheless and which has implications in cosmology.
You don't need an edge for resonance, just for waves to be able to "meet themselves". One way for this to happen is for the resonating object to be finite but not bounded. For example the surface of a sphere, considered as a 2D surface, has resonances (spherical harmonics) because a wave can travel around the surface and 'meet' (interact with) itself... it does not need to reflect.
This has a very significant application for cosmology.
We know very little about the universe at the very beginning of the big bang (just before the inflationary period). Inflation took whatever was happening and 'blew it up' many many many many times. It could be that the part of the universe we see is just a tiny bit of an infinite universe all or part of which was caught up in this inflation. But it is also possible that what expanded was a finite universe with no edge (a higher dimension analog of the 2D surface of a sphere). In that case there might have been harmonics within the early universe, and these would show up as patterns in the cosmic microwave background.
Scientists looking for this pattern mostly don't think there is one, hence the general idea that our visible universe is a tiny bit of something much larger (maybe infinite). But there are some tantalizing hints which some scientists think might be traces of just such harmonics in differences in the hotter and cooler areas.
We may never know... any pattern is just a glimpse and maybe not enough to say for sure. But the possibility is there, and the idea quite interesting.
I agree, it's why I put up the quick image of the torus as a geometry that could get set up a wave without an edge. :) I felt like going too far into the discussion of boundary conditions would be going into too much detail.
Your channel is awesome I wonder why it hasn't got milions of subscribes yet. Great work thank you.
Speaking of waves, what happens to the energy of the photons involved in destructive interference? I have addressed this question quite a few times to Physics teachers and the best answer I have been given (actually, the only answer) is that "our lack of understanding of quantum mechanics makes it difficult to answer this question".
As energy cannot be created nor destroyed, the photon's energy must go somewhere, presumably converted into virtual particles or something?
That's a good one:)
azmanabdula Short answer, dark energy is a complete mystery so far, but there are loads of experiments here on earth trying to find dark matter(it is hoped that it actually interacts with matter weakly). I wouldn't be surprised if we have concrete detection in the next decade.
Dark energy and dark matter are names given to observable phenomenon, the acceleration/speed of the expansion of the universe and the missing matter responsible for the gravity holding galaxies and large bodies together, respectively.
As we have little understanding of the origin of gravity it makes sense to me that until we know more about gravity we can't possibly know about dark matter, being even more elusive than gravity/theorised graviton. Dark energy could possibly be the result of the universe travelling through whatever is on the outside of the universe, so some things we may never be able to understand.
I enjoy the challenge of contemplation, learning and discovery, and although it can be a very painful process it keeps us motivated and thinking. Having a cake and eating it, would be the stance of a religious mind in my opinion :)
Did you really have enough sleep? you look like a badger^^
phycists don't need sleep
Awesome video, TGP :D
i wonder if you could make the wave meet its self by using a wormhole
Is it possible for gravitational waves to bounce between two or more black holes or pulsars and eventually resonating the space time between them??
The boundary (of curve space of mass) is gravity field it self. The resonance could be happened (for anything) inside the gravity field.
How about that
But would it be possible for two sources of waves to interfere with each other in such a way that for someone looking from the side it would look like a standing wave??
Isn't the speed of light a de facto boundry? Since the phase velocity can exceed the speed of light , the wave front itself is a boundry.
Dude! There's no EDGE!
But like please get some sleep.
Would the Foucault’s Pendulum come to a complete stop by its own eventually?
Could 'dark energy' be a quality of space itself? (Struggling to ask this question sensibly - perhaps you could re-word / re-phrase.. in essence i'm just thinking about the nature/elasticity of space as it stretches/expands). I appreciate your work - thank you kindly : )
Yes
this aged really well.
You remind me of Dane Dehaan.
How physically possible is Spiderman?
I have a question regarding measuring intergalactic distances, maybe you can help:
[TL:DR If I look at an object from twice as far away it appears half the size. Why can't this method be used to measure the distance to galaxies?]
I understand the need for standard candles and red-shift for these measurements, however it only makes sense (to me) when talking about measuring distances to point objects, but galaxies are not points.
I'm sure there's some error in my thinking, but; knowing the actual size of the galaxy you're measuring (at least to within an order of magnitude approximation), and knowing the field of view of your telescope in arc seconds, could you not ask "What distance must that galaxy of diameter X be to appear diameter Y in arc seconds in my telescope?
For all I know this method *is* used, but I wouldn't exactly call myself ignorant of astronomy, so I'm curious why I've never encountered this reasoning before.
To a certain extent I think that method is used, but problems show up due to the fact that not all galaxies are the same size, and really distant galaxies just look like a point. They are so far away, we can't make out individual stars. (That said, astronomy , particularly observational is not my strong suit.)
Thanks for the reply, I thought this might be the case. What I'm really interested in is comparing this kind of measurement to our red-shift measurements to see if they agree, even if we can only use galaxies near our local group. I have no doubt that the data will agree, but it's another way of testing universal expansion, and who knows, maybe it won't agree, and Hubble's Law may require a different kind of explanation (Light speed increasing with time?). Cheers.
TheResidentSkeptic
The sizes of galaxies are indeed one method people try to use to get at distances, but this turns out to be a pretty messy method. The problem is that
1) there is a huge amount of variation in galaxies
2) galaxies in the past were not necessarily the same as they are now, so if you look at very distant galaxies you can't be sure they are like the ones now in size etc.
There is a good article on all the different methods astronomers try to use to get at very great distances (including your idea and others) here:
spiff.rit.edu/classes/phys240/lectures/distant/distant.html
Philip Freeman Wow, thank you. This is a fantastic resource. The concordance of evidence is clearly stronger than I thought.
hi, an old question i've been trying to get an answer to.
if i have mass m of matter, and mass m of antimatter, and annihilate them perfectly, does the matter and antimatter cancel, giving e=mc^2, or do the matter and antimatter unravel each other, giving e = 2mc^2?
and, pushing my luck on the number of questions i can ask, can a gravitational wave be trapped inside an event horizon of a black hole?
could a black hole therefore resonate internally with gravitational waves?
The total energy is 2mc^2, and I don't know enough about black holes to answer the second part :P
Why can't things travel faster than the speed of light? Surely if two photons traveled at the speed of light in opposite directions, wouldn't one would be traveling at twice the speed of light away from the other? Isn't speed all relative? Why is there this universal speed limit?
Ok am I the only one who is mesmerized by this dude's eyes lol.. yea he's got dark circles but i'm looking at the color of the iris. Maybe the dark circles accentuate it lmao.. maybe there's some alien DNA there (no offense, most of us have it) Some of these comments are funny as hell tho xD
i thought nuke boxes made water molecules wiggle and jiggle and the friction(?) made that heat up the food and why paper plates don't burst into flames n shit.
You're right, but it's the electromagnetic waves that make the water molecules shake.
NO EDGE
Well we now have direct evidence ;)
Destroying the physics of the Marvel Universe, one youtube video at a time. :)
But would it be possible for two sources of waves to interfere with each other in such a way that for someone looking from the side it would look like a standing wave??
I suppose you could, but I still don't think it would count as a resonance, there would be no way for the wave to build up over time.
In a theoretical situation, what would happen if the universe started resonating? ( let's say it had an edge and everything else that is needed?) What are the consequences of that?
If you could build up a large enough gravity wave(really hard to do) , I believe distances between points would grow and shrink noticeably.
Hey thanks. You're awesome