What is Energy?
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- Опубликовано: 2 окт 2024
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Energy is the most powerful and useful concept in all of physics, but what exactly is it?
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Kronos: Devourer of Worlds
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Written and Hosted by Matt O'Dowd
Produced by Rusty Ward
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In physics energy is not a substance, nor is it mystical. Energy is a number. A quantity. And the quantity itself isn’t even particularly fundamental. Instead, it’s a mathematical relationship between other, more fundamental quantities. It was 17th century polymath Gottfried Leibnitz who first figured out the mathematical form of what we call kinetic energy - the energy of motion. He realized that the sum of mass times velocity squared for a system of particles bouncing around on a flat surface is always conserved, assuming no friction and perfect bounciness. Leibnitz called this early incarnation of energy vis viva - the living force.
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No energy was lost or harmed in the making of this video
Some energy was dispersed into a higher entropy state though
Yeah it was all just a huge waste of time.
@Draw your life no my friend nuclear bombs merely transform energy held within the nucleus of atoms. I think you're thinking of mass when a small amount is turned into energy during any explosion. And yes even though mass is turned into energy, energy was not created or destroyed because remember Einstein's famous equation says that energy equals mass times the velocity of light squared, so mass is energy. Mass is an emergent property of certain particle interactions while energy is a fundamental property of the universe. So you can create or destroy Mass but you can only change the distribution of energy.
@Draw your life Yes Matter (not mass) contains a lot of energy. So its not created or destroyed but merely trapped. "Destroying Matter" merely releases the trapped energy. Most matter was created at the big bang though so we often don't think about the energy it contains because its been trapped for so long. When the sun fuses elements into heavier ones, it releases a tiny amount of the trapped energy within matter. Similar with fission as Iron is the lowest energy state that stable atoms can be in.
You can also create matter from energy. There are physics labs that create a small amount of matter and anti matter by concentrating energy to a small location then filtering out the matter and anti matter. It takes a lot of energy to create a tiny amount of matter though.
"a physicist sees a guy standing in the rooftop and shout don't do it you have so much potential"
For whatever reason i instantly laugh so hard
far too hard to be OK xD
Long as it doesn't last more than 3 hours he should he fine. Any longer and he might want to seek a physician.
The stoic delivery, and just the unexpected nature of seeing this in a PBSSpacetime vid made it for me. I knew the joke already, but I totally didn't see it coming. I was seriously getting ready to think/paying attention to the intro.
#MeToo
#MeToo
At least Space Time is here for me on Valentine's Day.
Yeah, good thing there's something to cheer us up today. I really love how deep these episodes became lately
Hopefully SE 0.9.9 will be there for me on my birthday ;)
😂😂😂😁😁😀😀☺☺😐😐😟😟😟😧😧😭😭😭😭😭😭😭
So... what's energy?
You seem to have skipped that part.
Energy is a fundamental property of particles. All things have it.
@@hiimpact3669 I think the spacial transformations are caused by energy. Not the other way around.
He didn't skip it; he said it is a bookkeeping aid. See lecture 4 of the Feynman Lectures: www.feynmanlectures.caltech.edu/I_04.html
He jumped on Newton's head and started bashing, other scientists with Einstein's energy 🤪🙄🤪🙄
Energy is energy, too bad, there was so much potential here which was wasted.
You seem to have skipped the part that explains "what is energy?".. However, it appears that nobody can exactly define what it is. Leibnitz and some others defined it as "the potential to do work". I have not seen or heard any better definition yet.
If bored, read Leibniz views on God (and perfection and theodicy, etc)
Aristotle has a good philosophical approach to potentiality and actuality, where the term energy came from. he was specially against the numerical approach to physics though, but well, quantitiable and measurable things which we can assign numbers are just an aspect of reality
You seem to have skipped part of the video. At the beginning and @9:40 he says what is energy in physics, its an accounting tool, a concept we created to relate more fundamental things together. There is no physical thing called enegery that exists out there and that flows and transforms, as some woo woo gurus would like you to believe.
@@aliismail2962 If that's so, what "travels" down (around) wires? It has effects that we can predict. What is it? Accounting tools don't have effects, they just keep track of the effects. So, what is energy?
"Energy is a number." 0:53
"Mom, i'm not doing anything, i'm just conserving my potential."
"son, use that potential energy and take out the trash or my kinetic energy is going to apply force to your butt.
"So dad can I have another burger? I need more potential."
It looks like you didn't understand the concept well 🤣
Mom: You need to be more kinetic.
Jonathan Kehn he can't use that energy cuz first of gravitational potential needs a height/Y-axis taking out the trash would generally be working with the x-axis and since ur height doesn't really change in that action or gravitational potential should be the same for the most part, therefore he can't even use that potential energy, unless he was in the second floor and the mom threw him out the window into the trash then he can make use of that potential energy, C'mon bro do u even physics
You matter
Untill you multiply yourself times the speed of light squared
Then you energy
😂😂😂😂✌
"Then your energy" and it's not a fact
Blue Light76 you’re*
@@FirstNameLastName-tc2ok thxs
The Manan J you string
Haha that intro punchline
I look like that pos in your profile pic fuck
“Don’t jump; you have so much potential!” I’m still laughing! 😂
Unless it is Einstein seeing the guy on the roof, he was always keen talking about people falling off them. From a purely equation perspective of course.
Physicist Richard Feynman’s thoughts on Energy:
“There is a fact, or if you wish, a law governing all natural phenomena that are known to date. There is no known exception to this law - it is exact so far as we know. The law is called the conservation of energy. It states that there is a certain quantity, which we call “energy,” that does not change in the manifold changes that nature undergoes. That is a most abstract idea, because it is a mathematical principle; it says there is a numerical quantity which does not change when something happens. It is not a description of a mechanism, or anything concrete; it is a strange fact that when we calculate some number and when we finish watching nature go through her tricks and calculate the number again, it is the same. (Something like a bishop on a red square, and after a number of moves - details unknown - it is still on some red square. It is a law of this nature.)
…
It is important to realize that in physics today, we have no knowledge of what energy ‘is’. We do not have a picture that energy comes in little blobs of a definite amount. It is not that way. It is an abstract thing in that it does not tell us the mechanism or the reason for the various formulas.”
www.feynmanlectures.caltech.edu/I_04.html
This is not a LAW but a theory!!!
You give a 300 year old theory more credit than is dew... The universe is infinitely more complex!!!! Explain how the Universe is accelerating its expansion using Newton's Theory? Or power circuits using superconductors. Or super fluids that defy gravity using capillary forces. Or try explaining magnetic energy... yes energy... using thermal dynamics? Or charging a capacitor through a load then using the power in the charged capacitor to power the same load? There are hundreds of other examples ignored by mainstream science. The fact is you have bought into scientific dogma!!! Which is not science at all!!!
@@dee5556
Sorry but there is no theory called the conservation of energy. There is just a physical law by this name. The law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be conserved over time. The law only applies locally, that is, within a single system that has time translation symmetry, so it does not apply across the entire cosmos (e.g. between very distant galaxies). The law isn’t 300 years old either. It was discovered by Julius Mayer in 1842. It’s just 178 years old and it has been confirmed many times since using modern science.
I’ve bought into nothing. I provided Richard Feynman’s thoughts on Energy. I understand the abstract notion called Energy well so I know that he is correct. But he is more articulate about Energy than me so I quoted his words. I await the publishing of your peer-reviewed paper overturning the standard understanding of Energy. There are no shortage of doubters and cranks but they never come with evidence. Until they do, I’ll stick with the masters that I understand. And the universe is actually quite simple, but big. Big is not complex.
@@cloudpoint0 " I await the publishing of your peer-reviewed paper overturning the standard understanding of Energy."
Perfect!
@@dee5556 lol
Hey matt i am an 11th grade student but due to pbs spacetime and infinite series and some other channels made me develop intrest for quantum mechanics.
Now i have finished 'Introduction to quantum mechanics by david griffith'. Thanks🖒🖒
Ps:- I am a Biology student and giving NEET in 2020
Yug Chauhan Keep at it and you might just one day stand next to Matt.
In my case - they taught most of this at school (yeah, our school teaches physics and chemistry (mandatory) from 5th grade upwards until University) couple of years of astrophysics aswell, sadly I found it utterly boring, being a lazy teenager and all. Now I totally regret not listening. While most things jog a memory here and there back to my school days, most of it I have to relearn again. So keep at it and pursue your dream.
Hey Yug! If you're in 11th grade and have already finished Griffiths then the physics world needs to watch out for you!
Congratulations! I finished Griffiths in the 4th grade, of physics' graduation!
You should read the bible instead and learn creationism by ken hamm. Ever wonder why bananas are curved unlike earth?
Dave B - Checkmate, atheists! You got em.
You can't finish a physics videos by stating that energy isn't conserved in cosmological scale and not further develop your statement.
I demand a follow-up video!
We are clearly missing some great parts of the energy-conservation equation. Since matter is condensed energy, and the universe is filled with matter, where does the energy come from?
I guess it's the 'magic' Big-Bang creationist theory that magically explains it. And then we have the 'magic' expansion of space (dark energy) that for some reason increases the potential energy of everything (things get further apart = more potential energy), but doesn't seem to require any energy to happen.
I so look forward to the James Webb telescope coming online, and then the astronomers will find some nice galaxies a couple of billion years older than the universe. I'll laugh when they'll retcon the BB theory again to fit those 'impossible' galaxies, adding some mumbo-jumbo physics to boot.
I just made a sort-of follow-up with that concept applied to spaceship re-entry. Might be interresting :)
Solitary Mind,
The universe as whole or over very large distances (megaparsecs) isn’t usually viewed as conserving energy since there is no common reference point for time (it lacks 'time translational symmetry'). But there is a conceptual way that the universe can be viewed as conserving energy. Dark energy is added to the universe, this a positive energy. But the universe’s total potential gravitation energy (or curvature) increases by the same magnitude, and this is negative energy in the cosmological accounting system. This isn’t practical for any calculations, so it is ignored, it’s just conceptual.
motls.blogspot.ca/2010/08/why-and-how-energy-is-not-conserved-in.html#disqus_thread
It does follow from the logic presented here, but in the expanding universe case they use heat energy, not kinetic and potential energy. As the universe expands the heat energy changes(U) but without work being done, it's in the enthalpy equation.
Also we don't know if we can consider the Universe as a closed system. Surely the observable universe interacts with what's beyond the observable limit.. And so on and possibly on an unlimited scale.
What a cliffhanger! My guess is that it has something to do with spacetime and how energy is a representation of that effect. Next thing you know, Matt will tell us energy isn't real and it's only an artifact of our limited perception of our reality. I'm grasping at straws here. I can't wait for the next one. Best channel on RUclips Matt. Keep up the amazing work.
I agree. The more we know, the less we know.
They couldn't have picked a better person to deliver the content on this channel. Matt has the most relaxing voice, anybody else put on space time before bed? I love the content of the videos, but inversely I can also just listen and let it lull me to sleep without fail. Growing up is weird 😜
I have anxiety issues, so I've recently started listening to these videos before bed because learning helps me relax. So, I fall asleep easier after watching a couple of his videos. They are interesting and relaxing. Not boring.
"Lithium is grunge, not metal" That's the best thing I have heard all day!
Nirvana forever
@@LuisSierra42 Was about to get all upity about "in my 20+ years of chemistry, i've never heard it called grunge".... then got it finally :P
What's grunge?
@@aminlah8027 Oh my young sweet summer child...."Passes you a CD with Nirvana, Smashing Pumpkins, Pearl Jam and Alice in Chains on". Here is your research material, they will be on the exam. :)
The only thing getting me out of bed in the morning is needing to pee. Not feeling energetic.
Pee has potential energy, when it is in your bladder, and when it falls into the loo, it will have more and more kinetic energy and less and lees potential energy. Until it stops falling down. It is a pity, that you do not feel more energetic after using the bathroom at all.
A physicist sees someone standing on top a building and he shouts
Convert your GPE into angular momentum, flipping your body as you hit the pavement!
EVERYBODY DO THE FLOP
*"Do a flip!"*
- Bender
Find the angle φ
It's blue isn't it?
Flipping *before* hitting the ground... i don't think you would do much flipping when your face hits a stone floor...
Wrong units. Potential energy is joules and momentum is kgm/s
This could've gone into Gauge Symmetry, which would've been VERY interesting - albeit difficult to explain accessibly, but if anyone can pull it off it's PBS SpaceTime!
Still wouldn’t have told us what energy is. Just like the video....didn’t.
0:06 I died.
Like, collapsed onto the floor.
My heart stopped beating.
That was amazing.
So... what is energy?
good question.
At the 7 minutes mark I was like "This video could be named The Essence of Langrangian, Hamiltonian and Statistical Mechanics" then I had a nerdrgasm. I love this channel so bad!
*Passes you a tissue for your nerdgasm*
The way he holds his hands makes me want a Hershey's Kiss.
KungFuBlitzKrieg oh....... my...........god
I can't stop looking at it
NO! You're not supposed to be telling everyone, now our brainwashing won't be secret. 😒
Lindybeige would give this particular scholar's cradle a 7/10. Decent shape, but he needs to keep it closer to his chest ;)
Peter Hell -- thank you for your service.
it surrounds us it penetrates us it binds the galaxy together.
But unlike Energy, Dark Energy is accelerating the expansion of the universe, we must restore the Jedi Order. We must restore balance to the universe.
And it means that eventually you'll have to change the Floors ;))
Major Grin may the energy be with you young padawan!
To say that if the Jedi dies, the light dies, is vanity. Can you FEEEEL that?
The 'Force' and 'Dark Energy' have one thing in common, they are both figment of the imagination.
Sad that it has only been relatively recently i have even heard of Emmy Noether, and now Émilie du Châtelet. Wonder how many other women have made great contributions to science that we almost never hear about. Maybe a Space Time special on some of the less well known women in science?
Male discoverers of dark energy? Here's your Nobel, as soon as we could get it to you. Female discoverer (Well team leader) of dark matter? Dead now, never got one. There are so many stories.
You've never heard of most of the men who did physics, either. Physics is not taught historically. Basically, the only physicists who are remembered are those who get something named after them, and even then the most you know about most of them is their names.
The previous two commenters, Justin and Michael's wittle feelings are being hurt by the possibility that misogyny exists. Poor dears.
tillyqtillyq , you resorted to ad hom without provocation. That’s an automatic disqualification from civil discourse, not to mention any potential debate. The two commenters you referred to have officially and objectively defeated you in the short exchange.
@@tillyqtillyq3750 Not only does misogyny exist, it persists [patting you on your pointed little head]. Maybe one day you too will be wise
An amazing summary of key milestones of last 300 years of physics. Man, you know physics and no doubt you master how to teach it! Thanks.
Might be easier to just ask what isn't energy :3
This is a very good question, and a good one for a next video of PBS Space Time. I think, it is even more difficult to tell, what is not energy, then what is energy...
+Achatina Slak Especially when you get down to the quantum level of things/reality. That's when it gets real weird and you start to wonder what the relation of energy really is to the world. Or if its all just a potential in different forms.
In the same time, energy is just mathematical formalism that is not fundamental. So nothing is energy.
Low Energy Jeb
Exactly! Is seems like everything that physically exists is made of it, and there isn't anything else.
They say if you are early, he might give you super energy
Michael Ortega they say if you are early enough, a black hole will appear under you and swallow you.
All we know is that it's called PBS Spacetime
They literally did NOT say any of that. n00bs!
well, i suppose i’ve missed that window.
@@banter7663 eeèeeè
Next episode: What is Information?
You won't get it. By hook or crook
binary bits
Information is entropy
@@freedomisnotforsale what's entropy?
@@vol230 blood of gods, essence of the space and time, and result of universe decay.
Energy is...
A. Light
B. Second creation after void/dark energy.
C. What everything is made of.
D. Love manifest.
E. All of the above.
Energy, a permission to do something (whatever).
Wait, you mean it's not something that comes in cans at 7/11?
technically it's also that
And coal and uranium.
But don't eat those.
I eat uranium. It's pretty good once you get around the whole "it's going to kill you" part.
CALM DOWN MAN! It is, these guys don't know what they're talking about. My favorite is the one that you don't need a can opener, just pull up on the tab.
Sebastian Elytron wait... Youre the guy that said Lithium is grunge not metal
Now I demand a Quantum Hamiltonian Operator rap and musical
alarcon99. Sorry rap is not music. Jungle drums.
Different subject, but someone made a song taking a paper and using the abstract on Quantum Decoupling Transition in a One-Dimensional Feshbach-Resonant Superfluid: watch?v=FIXRXMMlZBM
I brought my homeboy operator J_z, famous rapper of total angular momentum. I brought
a^{\dag}, don't mess with him because his adjoint will deck your ass. #SpinUp The time reversal operator died for the #SpinUp movement. #SpinUp son
alarcon99 You're in luck! Here's an acapella version of the Hamilton theme, based on the life of physicist W.R.Hamilton, featuring a bunch of science youtubers!
New symmetry/conservation law: If the universe has expectation/reality symmetry, then feelings are conserved.
Does this mean when space gets compressed due to , let's say a gravitational wave, light's wavelength shortens and at that moment it gains energy from nothing ?
Yes, and the cosmic microwave background has been stretched, losing energy. There ARE ways to get around this, involving the energy of curved spacetime but they can be a bit tricky to visualize.
Man... you know, this video has special relevance to me. In high school I remember learning about potential kinetic energy and being convinced that it couldn't be right and was just a tool for math. I went on to learn about space curvature and felt vindicated enough but still curious. Here you introduce concepts that both make it workable in my mind and motivate me to learn what it is in Einstein's work that made me so sure upon hearing it. Too bad I suck at math.
Then focus on what it means in a natural sense. If these things are true, how are they applicable to things as we know them. What *is* life? What *is* the universe we inhabit? That's basically what I do. It's the new philosophy.
That opening joke legitimately made me pause the video so I could stop laughing.
You are lying no one laughs at physics jokes, its more like ''heh heh yeah good one!''
@@ConceptNull kinda true
Q: What is energy?
A: Ability to do work. Next question.
And resistance to alteration of velocity, momentum or state vectors...
The next question: what is work?
+Richard Braakman transfer of energy
I despise that definition. It tells me nothing.
@@meaquidemsententia Go to school then. Dave B gave perfect answer.
9:05 come on
You guys are just throwing symbols around
My favorite is the sword!
mathsbyagirl.files.wordpress.com/2015/10/tumblr_ms7xuthyhv1qc38e9o1_1280.png
This is the Lagrangian for the whole standard model :)
To be fair though, it's written in the absolutely longest, least useful kind of way. Physicists would never touch it in this form.
Oh you sweet summer child. If you think that is throwing symbols around, you should look at the complete derivation.
+BER-SER-KER MORE SWORDS!? Does to dual wield?
What do you mean "derivation"? This is the definition of the theory, that is, this is the starting point. This is the quantity you derive other things from.
Is there a property more fundamental than energy that is conserved with regard to general relativity and the accelerated expansion of the universe?
There may be, something relating to 'energy-momentum four vectors'. In essence you'd take into account the expansion and curvature of spacetime and could use that to predict energy loss or gain in certain situations. But man is it tricky to understand.
excellent information and presentation. So many interesting questions and directions to be explored. Truly enjoyed it
You seem to be confusing a method of describing energy with energy itself.
-"We all know what it feels like to be energetic! "
-Ehm... No..
When I binged your channel I didn't pay attention to the fact that videos were released only weekly. The last week has been too long. Finally a video!
People use "Bing"? I wonder if there's ever been a study on the "accuracy" of search engines' results. Anecdotally, I daresay Bing ranks poorly. [Edit: No pun intended, but I should have been proud if it were!]
Yo yeah dude cause it totally makes more sense for me to make a shitty reference to Bing rather than use a conjugation of the English verb "to binge".
...tbh I thought you meant Bing too. lol. Probably because I usually hear "binged on x" rather than "binged x"
I knew he meant binge
I would say Occam's razor, but to be fair my perspective is from that of someone who doesn't use Bing nor knows anyone who uses Bing.
My cat has 0 energy except at 11pm when he puts the sun to shame😀😀
Such a tease! That wasn't describing energy at all, just how we account and track it! What is energy?! I must know! A sum of vibrations in all the fields? What's vibrating?!
energy just means change. a vibration is just one kind of changing system.
Noether's theorem is not to be confused with No Ether's theorem, which was proven by Michelson and Morley.
3yrs later, this comment is still under appreciated!
4:10 - INFERIOR SIEGE ENGINE ALERT!
So.. Energy is an accounting tool but more interesting? Fine, I accept it.
Read the -first- fourth chapter of the first volume of the Feynman lectures.
Your mom does too
@@michaelsommers2356 I, < uo
Hermetic Xhaote ಠ_ಠ
once i feel very boring and lazy feeling. I say my advisor in locked gravitation loop. i get 1 hour extra school
I believe quantum gravity is relevant to this. To me, space-time is the potential for motion and energy is convolution of space-time. So the title of this vid translates to, "What is convoluting this show?" or, "What bends this show?"
I've had these questions for a while but this seems a good place to ask:
Does inflation obey the conservation of energy? For example, do galaxies gain potential energy relative to one another as they are pulled apart? Or in other words, if you had a many light year long and infinitely strong rope (let's assume it's actively supported) attached to a large mass on one end and coiled at the other, could you extract energy from the coil spinning as it unrolls?
And; Is Gravity itself relative in general/special relativity? Is apparent gravity relative to your reference frame? Does apparent kinetic or potential energy increase the apparent gravity of an object? For example, an object moving very near the speed of light has a greater apparent mass. But does it actually curve space to a greater degree? It seems like the answer must be no, because this would lead to objects appearing to collapse into black holes depending on your frame of reference. But how does this work?
*Does inflation obey the conservation of energy?* Maybe and sort of, in the sense that addition curvature is added to spacetime during inflation (a negative energy), and if inflation is like dark energy on steroids, then additional energy is added to each unit of space during inflation (a positive energy). The two should cancel.
*Is Gravity itself relative in general/special relativity?* Gravity is just applicable to GR. In GR, gravity is explained in geometric terms (curvature) of space and time. Relative means two observers traveling in respect to each other may have different perceptions of time and space. So the answer seems to be yes for GR.
Sorry that I did not answer your more-specific thought experiment questions. I don’t know how to deal with a rope that is megaparsecs long. I think one end of the rope would not even be aware of what the other end is experiencing over that kind of distance, or at least there would be a huge time lag that you would perceive as a long stretching of the rope. I don’t think an object’s *apparent* mass has any effect on space curvature. An object’s *true* mass has not changed just because it is moving near the speed of light, and therefore its volume is still larger than its own event horizon and I assume nothing changes like it becoming a black hole.
Energy is generally not conserved in GR and this is especially the case with the expansion of the universe. As photons get red-shifted due to expansion their energy is lost. Also mass increasing with velocity is a rather outdated concept. The effective force is what is considered decreasing with velocity in relativity now.
An object moving faster will have increased gravity, but only to things that see it moving fast. An 'isolated' object like a single proton, cannot collapse into a black hole no matter how fast it is moving because from its perspective it is sitting still. (If it could , 'regular' protons could do so all the time.) Only when it's in combination with another body will such things happen. When this involves the cosmic microwave background the proton-photon pair can combine over a certain energy known as the GZKlimit. (Either the proton is moving fast, or the photon is blueshifted to a gamma ray.) So a fast moving body has a different gravitational effect compared to a slow moving one and this difference syncs up perfectly with things like length contraction and time dilation so that all observers will agree on what events occur, even if they disagree on the strength of gravity and time it acts.
The rope doesn't work as 'infinitely strong'. But given such a setup you COULD extract energy, 'Big Rip' scenarios take this to an extreme. What happens depends on the tensile strength of the rope. Any body whose internal forces are greater than the expansionary force will simply hold together; space in essence will move out from them. So if your rope is stretched taut you can't get any energy from it, it either snaps or stays exactly the same. Of course, as noted, long ropes end up needing to take relativity into account when dealing with the forces on them.
well... I'm not an expert, but the answer I think is No. Energy, as the conservation of a system symmetries over time is tied to the spacetime. The inflation itself is a distortion of the spacetime. So it is not strictly an event caused by energy, but by the gravity (which is a distortion of spacetime). In that way, gravity is not relative based on the observer or the reference frame, as it is directly tied to the mass of the entity under observation (and its piece of spacetime affected), not the observer.
I don't know if you read this... but I'm going to request a video on the off-chance you do. Can you explain the difference between the Lagrangian and Hamiltonian point of view? Not just mathematically, but what it really means?
The math is what it _really_ means though. You want the humanized explanation, it is a ‘point of view’ after all which innately means it is subjective. I know what you mean, just pointing out that the words need to be careful in science, else we get bs like ‘evolution is just a _theory_’ etc
Lagrangian and Hamiltonian formalism are more or less equivalent mathematical descriptions of the same physical processes. For some the Lagrangian formulsm works better, for others it is the Hamiltonian that give the most insights. There really isnt much more to it than that. Neither the Lagrangian nor the Hamiltonian are quantities that can be directly measured, just like Energy cannot be measured directly but has to be computed using other measurements (for example mass and difference in distance and time in classical mechanics). So they are mathematical objects (with some physcal interpretation) that help to formulate the theory and compute other things.
The only reason why you have not asked what Newtons formalism really means, is because you are so familiar with it that you have just accepted it. But of course the idea of a force is in some sense just as abstract than a Lagrangian.
Midichlorian is the name of next energy particle. Im calling it.
Thank you for answering my question.
Greetings everyone, this is my working definition of energy.
“Real energy” means the change in a system. Typically, when people talk about energy, they specify which flavor of change they mean. If you remove time, you remove the energy (because nothing can change). Energy is never a substance, nor can it be negative (because of the unidirectional nature of the time dimension - there is no true negative change in our universe). Energy is just an observed characteristic of various changing systems.
“Potential energy” just means that during normal operation, a system owes you some specified flavor of changes in the future (you are in effect, saving changes).
For example, a city needs extra energy to change things in it (because they mean the same thing). So, a power plant is really a “change source”. If you have a battery as a power supply, you really have a “pool of changes”. If you disconnect all the change sources (turn off the power), you will starve the city of changes (and everything grinds to a halt, a bit like in the “The Day the earth Stood Still” movie). No energy means no change.
More speculatively, regarding the nature of "change" in general:
a. Something must change (this is the structure of the universe - aka, information).
b. Changes can occur in both space and time (due to the existence of space-time).
c. Changes should be no-time entities (not imply time-only).
d. Systems that change a lot, in the time direction of space-time, are called “energetic”.
e. Systems that change a lot, in the space directions of space-time, are called "dense".
f. “Lots of change” (in both space and time) means the same thing as lots of space-time bending (like gravity).
g. This why dense or energetic systems have lots of gravity.
Thanks for listening. ;)
Thanks a lot!
John Weck
Oh bro) Is ))) Energy is scalar physical quantity, which is a single measure of various forms of motion and interaction of matter, a measure of the transition of motion of matter from one form to another. You can not transmit energy. And it doesn’t have form. And yes, it cannot be destroyed.
John Weck finally smart comment
Well done ,
How would you differentiate energy from entropy? Thanks for the detailed explanation. I've been searching for an intuitive definition of energy forever and your description is the best so far.
Energy, the ability to cause movement or change. To transfer Energy.
I sleep a lot because I believe in conserving energy.
U r wasting ur breathe, its already conserved. Now move ur ass and increase some entropy.
That Lithium Grunge joke at the end is actually next level.
Question!:
Before the Big Bang,
Can we consider the Universe with a state of infinite Potential Energy?
Ask your mom.
Yes...... Imagine the otherside/outside of a black hole.
I would love to see a “what is entropy?” Episode or series.
i make a video: Entropy and Happniess, about Entropy vs Energy!
I teach AP Physics 1, and this is such a great supplement to the work that we do in class. I teach some very curious students who will definitely appreciate this.
Your students must be quite *energetic*
He didn't answer to the question. The entire video is jumping from subject to subject. Unfortunately this video is terrible.
The core of the Hercules - Corona borealis Greatwall spins very quickly like A super large electric turbine that produces super large electrical energy. Every second the Hercules - Corona borealis Greatwall pushes out into space 2400 billion billion tons of photons move circle at light speed return to its original position after 93 billion years, so it pushed the entire universe to spin
Can you please make a separate videos for Lagrange Mechanics and Hamiltonian Mechanics?
0:06 technically a suicide joke.
DEMONIZED
Among all these 2 year old comments, I knew this had to be new one.
Demonetized?
@@Leomerya12
Suicide jokes aren’t kid friendly so yeah.
My professor, with 40+ years of experience: You are wrong
Me: "Not wrong, just more interesting"
STOP SCROLLING AND WATCH THE VIDEO ..
I always thought energy and spacetime are fundamental but now it looks like only space time is fundamental
The structure of the universe (information) is fundamental as well. To get energy, you have to change those structures over time. Energy and change mean the same thing.
It's a clue to the deeper truly fundamental properties of spacetime.
Wow, talk about avoiding the subject. Love you vids.
The feel when you realize that in every video, the subject matter ends with the words "space time".
Let math say all the words when it comes to energy, duh. Philosophical view of energy has never been quite clear to me. I like the mathematical model much more than that.
It doesn't make much sense to compare the two. Describing something in philosophical terms is fundamentally different than utilizing its mathematical features. I think it's always worth while to try to understand an important concept in physics in a deep, philosophical sense; even though you may not arrive at a satisfying answer. A lot of great insights have come from intelligent people questioning the deeper nature of physical principles that were thought to already be fully understood to people who only cared about it was used mathematically.
If you only understand the mathematics of a physical concept without any deeper intuition about it (even though some areas of physics may be beyond the reach of intuition), then your capacity to look further and make logical connections with potentially deeper truths relating to it, is much more limited than if you are able to think about it in more philosophical terms and then return to the math attempt to verify the validity of that reasoning in rigorous terms.
bunklypeppz I gotta agree that you have a pretty convincing choice of words mate. Thanks. A thought just clicked my mind that maybe the lack of philosophical knowledge about energy could be the reason that they came up with the idea of dark energy in the first place and then weren't able to explain why is there so much of it in the universe.
P.S. I don't mean any offence to the physicists, I know those guys are brilliant minds, but still I sure have that big hole in the mind when I think about dark energy and how less we know of it.
A got a ranch ad after that joke.
Btw thanks for actually making an effort to pronounce the names of non-english scientists correctly (:
I'm a physical conservative: I believe in conservation of momentum and energy -- human enthalpy is the way forward.
PBS SpaceTime is the best !!
Yes, I'm sooo looking forward to their video on Emmy Noether.
What's the name of the background music at 4:05?
Darude- sandstorm
Argghhhhhhhh. You've explained very well what energy does and how it behaves but I still don't know what it is!
What is Energy? Energy is the force that produces work and heat in a system.
If energy is really nothing more than an accounting system, how does it bend space-time and create gravity?
Good question!
It doesn't. Matter does, and energy just describes it.
But light isn't matter and it exerts gravity and in previous episodes we see how mass is more or less an illusion created by particles that are restricted by the Higgs field.
It doesn't. Rather these things happen and energy is the accounting system that lets us figure out what's going on.
Consider photons in a box. Whenever two photons scatter (Which happens rarely) their frequencies can alter, but the SUM of their frequencies remains the same. It stands then that the sum of the frequencies of all the photons in the box is also always the same. If we want to be lazy we can just slap a symbol on this value (Let's say 'E') and say that that is conserved based on what we see.
If we smack two boxes together we find the same thing, the total of this 'E' thing is conserved, and what's more it doesn't matter how many photons are in each box, so we can separate E from frequency if we wish. PLUS the photons in each box affect spacetime in a certain way depending on their frequency and redshifting\blueshifting are things. BUT red\blueshifting depends on the total speed of groups of photons (Boxes). This means that the sum of all frequencies in a box depends on the relative motion of an observing box AND that the sum of frequencies (And thus E) of the two box system is constant.
So now we have a value that is, in essence just a measure of the frequencies of all the trapped photons and how they interact that, BECAUSE of how they interact is conserved and can be abstracted away from frequency conservation. We can call this 'energy' but everything 'energy' does is does only because it's based on something else, frequency. If frequency was got rid of, if it no longer affected things the way it did, then 'energy' would fall apart.
+Jason Diefenderfer
energy doesn't exist .. the same way how space-time , gravity and light don't exist ... you can't bend time .. time is arbitrary measurement unit ... we have no idea what is gravity , light - photons don't exist either .. just think about it that trillions of photons are hitting your eyes every second of your life at speed of "light" .. i think that your head would explode long time ago .. this mainstream pretending clown hunting subscribers doesn't understand himself what he is talking about ... if you want to understand something ,you can't walk with the herd ..... here is something which all you relativists should read ...www.naturalphilosophy.org/site/harryricker/2015/05/25/dr-louis-essen-inventor-of-atomic-clock-rejects-einsteins-relativity-theory/
I love to come back to older videos and still get new insights!
"Leibnitz was a competitor of
I. Zach Newton"
...lolol
You can borrow my gravity belt.Still working on the Suit ! Judging by this Energy you'll probably Do another show. .Good show! O No, I can't get this out of my Head. Nothing is solid that's the trick
It's not the spoon that bends it's only yourself. Hahaha the shows to short , don't Blink !
A whole episode about symmetry and super symmetry would be nice =)
So what you're saying is that energy is just a word we used to represent potential transitions in spacetime?
So what you're saying is that you're a lobster?
We should live our lives like lobsters*
That phrase is ruined now. Thanks, Newman.
Hah, Newman is the new Newman!
That struck me as well - 'energy' is described as being the sum of all its effects, or possibly the sum of the effects of all the other things in the system. That might be correct doesn't sound like the answer to the question. What we need is a better question!
I know that, I studied most of what you said in high school, so what's energy? I still don't know what it is
Energy is the thing that is conserved by definition when you apply time translational symmetry to Nother's theorem *except if you're doing general relativity
"We all know what it's like to have energy... to get up in the morning" can't relate 💀
If GPE = KE
mgh = 1/2(mv^2)
*dividing both sides by m
gh = 1/2(v^2)
2gh = v^2
Here 2g is a constant
Therefore v^2 is directly proportional to h
Proven.
I love you Matt, you're like the Carl Sagan of modern time, with just double speech velocity
Are fields energy themselves? I mean, the values that the fields can assume are what we interpretate as energy? If so, what would distiguish it from "matter"?
Energy is still a property, the time frequency of waves in those fields.
Cool but it's still confusing to me. I guess i need to watch it a few more times hahaha equations are not telling me a lot right now
Where can we fit the particles that transmit energy, such as photons?
For every kind of particle there is a corresponding field. Photon field, electron field, up quark field, tau neutrino field etc.
thedeemon i know man, that was not my point
Still waiting for the Hawking Radiation episode ...
I second this!
It's a big one, it takes time to record and animate, it's coming, but you need some breather episodes first.
You explained the mathematical description of energy, not what it is real and fundamentally.
Greetings. "Real energy" means changing structures in space-time. "Potential energy" means a change storage machine (or system). A power plant supplies you with a stream of standardized changes. A battery (or ATP in cells) is a change store. Bye. :)
@@JohnStephenWeck But time is a persistent illusion in GR...
@@ThePowerLover
ok, until someone shows that relativity doesn't work, I strongly suggest believing in time.
The comment at 14:00 about most stars having larger than earth size inner planets is interesting. I´ve been wondering about possiblity of the answer to the fermi paradox being simply, most habitable planets dont have land, so advanced civilizations don´t emerge because of the limits of life in water. Maybe thats an idea for an episode: could intelligent life become advanced enough to leave their planet if they have no land and live in ocean? Since we know that larger planets retain more water, it seems to be the case that any planet smaller than earth would not hold on enough water for life (see mars) and any world larger than earth would have to be completely covered in water, least so far as I understand it. Maybe the great filter is just... Did the intelligent life develop on land?
The question of how 'average' Earth is is an interesting one. The sun is larger and brighter than 75% of all stars, Earth might well be far smaller than most rocky planets (With an atmosphere.) 'Super Earths' can be expected to have more water, far thicker atmospheres, less light at the surface and more volcanism. All of which bode poorly for intelligent life. Not to mention things like whether our moon is vital for a stable climate. This is (a version of) the 'Rare Earth Hypothesis'.
Well in general I like the Rare Earth Hypothesis. I think that if we really understood solar systems, having a world that is like our own will seem a lot less common than we currently think it is. Still, if you manage to show that our planet is like 1 in a million, and that land dwelling intelligent life could only develop in one world out of a million stars, that would still leave the Fermi Paradox with a lot of worlds. Still, there are a lot of things that are pretty rare about our world. So you would be looking for a world in the goldilocks zone that is dwarf sized because of a tour de force from a Gas giant ate a lot of the useable matterial, that also had enough green house gasses to be liquid for a really long time (see young faint sun paradox), that also is a 3rd generation star, that is also not larger than our sun (larger sun means shorter life span, our sun is already only about 1 billion years from cooking our world), and not a red dwarf either, as the goldilocks zone of red dwarfs is hit by a lot of hard radiation from the more variable dwarf stars. Also lucky enough not to be hit by a GRB (so not anywhere near the core of our galaxy) etc etc. Also maybe needs a moon that was formed by a large collision to still have a molten core with enough magnetic field and tidal effects to help life develop and so on... etc.
FIRST!
Please do an episode on eternal inflation!!!
Oh. My. BGaaAAWWWDDD!! This episode was amazing! As an engineer, having learned _aalllll_ about energy throughout 7 years of schooling, this episode was spot on. It also somehow really boiled down the harder quantum stuff to something almost manageable. Amazing.
THANK YOU FOR SAYING THAT, that's EXACTLY how I felt!
Hmm I love this video, it explains absolutely... nothing! The energy is explained here is "the transformation of energy" in different forms of it and not what actually the energy is. Still people needs to admit that trying to explain in what it is known about this topic up until now is an interesting way to make a show.
@Dirk Knight well this is the common understanding, still it explains one part of what energy can DO and not what energy actually IS since it does not have a fizical form. Fizicians and and chemists can explain in their limited knowledge how the energy is transformed from one form to another (transfer fenomena), how it perform mechanical, electrical work etc, but can never describe the fisical form since it doesn't have one. After is transformed into matter then you might call it a "stored" energy in the forms of particles/atoms. Still the molecules can't perfectly describe the storage. Anyway it can't explain the initial state of it. The potential energy has nothing to do with transformed/stored energy.
That joke killed me
I know every single theory that was ever mentioned in this channel. Can you believe that advance physics like that are taught to Greek schools?
They are pretty difficult to grasp especially when you a 12 year Old and you just started high school.
Somekind of Dude English, please.
Cesar Pinto sorry not a native speaker and it's 3 o clock 😭
Somekind of Dude In that case keep going cause you've made pretty significant progress so far!
Cesar Pinto sarcasm 😔
Somekind of Dude I'm usually quite sarcastic, but it was a genuine compliment. For a non native (I'm not a native myself) speaker, you're pretty good
This is one of the episodes I'm going to have to watch 37 times...
Took me only 1 time. Rookie.
I wonder if energy is conserved at the multiverse scale?
Sure, why not. It's also conserved in heaven and hell. Imaginary theories can have imaginary conservation forces all day long.
The conservation of energy is only apparent in the local section of our universe. It literally makes zero sense when it comes to calculating the big bang theory.
Disclaimer: The big band theory doesn't actualy explains the big bang, or even TRIES to. It only explains what happened afterwards.
Well it's not even conserved within this universe, so there's no reason to think it will be conserved outside the universe.
It might balance out.
Energy is simply an inferred construct inferred from mathematics that has a fallible philosophical foundation.