I have a very nice book that is a collection of articles written by imminent scientists. One of them is by Einstein with exactly the same drawing as above and he is explaining conservation of energy and how energy can take different forms and change from one kind to another. In the case above you have kinetic energy at the bottom of the pendulum swing that transfers to gravitational potential energy at the top. Kind of also leads onto the idea of resonance where you have two forms of energy storage at play. In a LC tank circuit for example you are storing energy as electric charge in the capacitor or as magnetic field energy in the inductor so as the energy bounces back and forth, you get damped oscillation (just add a dash of gain and you have sustained oscillation).I looked into the subtleties surrounding energy conservation in general relativity in order to put some flesh on the subject.
Underlying energy conservation is the notion that physical properties and laws don’t evolve with time.
That may be true on Earth.
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However the distance between any two cosmic objects that aren’t gravitationally bound together does evolve with time.
That implies that energy is no longer conserved in an expanding Universe!
Enter Emmy Noether and her work on symmetry and conserved quantities - as described in the following link from which I have edited the above information.
https://bigthink.com/starts-with-a-bang/expanding-universe-conserve-energy/
I didn't understand that.
The troll that posted it doesn't understand it either.
I didn't understand that.
If you mean the Weiss/Baez article, then neither did I!
It was merely offered up for discussion in light of your mention of the "non-conservation of energy in gravity".
As I made quite clear in my post, "the mathematics in the John Baez article is well beyond me!".
I always read your links, Galu.
But I think I will put conundrums about Energy Conservation in an expanding Universe on the back-burner for now.
https://math.ucr.edu/home//baez/physics/Relativity/GR/energy_gr.html
https://bigthink.com/starts-with-a-bang/expanding-universe-conserve-energy/
It will take 10 years postdoc research to get near it IMO. The Maths is fierce! Maybe it is the product of Energy and Time that is Conserved. Er, makes up a name: ET-Conservation? Oh wait, that is the definition of Action! I amaze myself sometimes.
I shudder to mention this, for fear of what our learned member and electric plasma man, @cumbb will say, but Amateur Scientists have discovered Plasma in Space near M31 Andromeda:
https://www.bbc.co.uk/news/in-pictures-66807814
Turns out Drechsler and his buddies are pretty competent Astronomers:
https://iopscience.iop.org/article/10.3847/2515-5172/acaf7e
I thought to myself, it can't be hard to figure out what the turquoise blob is made of:
The Turquoise F-line is odds-on Hydrogen Beta, since most of space is filled with hydrogen AFAIK, and with all that talk of an Oiii filter being used, we can't rule out Doubly Ionised Oxygen.
That photo seems to be some huge long exposure composite image. On a 106mm telescope. I am impressed!
But I think I will put conundrums about Energy Conservation in an expanding Universe on the back-burner for now.
https://math.ucr.edu/home//baez/physics/Relativity/GR/energy_gr.html
https://bigthink.com/starts-with-a-bang/expanding-universe-conserve-energy/
It will take 10 years postdoc research to get near it IMO. The Maths is fierce! Maybe it is the product of Energy and Time that is Conserved. Er, makes up a name: ET-Conservation? Oh wait, that is the definition of Action! I amaze myself sometimes.
I shudder to mention this, for fear of what our learned member and electric plasma man, @cumbb will say, but Amateur Scientists have discovered Plasma in Space near M31 Andromeda:
https://www.bbc.co.uk/news/in-pictures-66807814
Turns out Drechsler and his buddies are pretty competent Astronomers:
https://iopscience.iop.org/article/10.3847/2515-5172/acaf7e
I thought to myself, it can't be hard to figure out what the turquoise blob is made of:
The Turquoise F-line is odds-on Hydrogen Beta, since most of space is filled with hydrogen AFAIK, and with all that talk of an Oiii filter being used, we can't rule out Doubly Ionised Oxygen.
That photo seems to be some huge long exposure composite image. On a 106mm telescope. I am impressed!
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That's a good electrical analogue of energy conservation in the gravitational field..
The charge momentarily at rest on the plates of the capacitor is equivalent to the mass of the pendulum bob momentarily at rest at the extreme of its oscillation. Energy stored in the electric field between the capacitor plates is therefore analogous to energy stored in the gravitational field. .
Wikipedia likens the to and fro movement of a pendulum to water sloshing back and forth in a tank - hence the term "LC tank circuit".
Perhaps we should now be revisiting the Oscillating Universe Theory?
Just don't tell TNT!
I read about that plasma arc in the BBC News report and had thought of posting about it myself.
Thanks for linking to the details behind the discovery.
I was also quite taken by the way that John White visually captured the sound of the black hole at the centre of the Perseus Galaxy!
You, too, must become more precise in looking and delimiting, differentiate and define. Otherwise, all that remains is mainstream populary noscience:
Universe cannot expand. Even according to mainstream Wikipedia it does not. "Parts" of "universe" "expanded", would "expand": "space" and "time": "space-time"-)
Step by step;-)
Universe cannot expand. Even according to mainstream Wikipedia it does not. "Parts" of "universe" "expanded", would "expand": "space" and "time": "space-time"-)
Step by step;-)
Is he still around?
On the positive side, Plasma Man has the ability to manipulate highly ionised gas.
He will protect us from the plasmoid full of ionised hydrogen gas which is leaking from Uranus.
https://www.sciencealert.com/uranus...ionised hydrogen, moving away from the planet.
I'm going to switch to Unignore for a trial period.
I must learn to be tolerant of contributors who hold an opinion at odds with what is generally accepted!
Remember Galileo. His view (turned out he was right) was completely at odds with what was generally accepted. He was in fact branded a heretic.I'm going to switch to Unignore for a trial period.
I must learn to be tolerant of contributors who hold an opinion at odds with what is generally accepted!
That said, I struggle with the ‘electric universe’
🙂
I have no difficulty at all with the "Electric Universe". I understood QED at a young age!
https://en.wikipedia.org/wiki/QED:_The_Strange_Theory_of_Light_and_Matter
I can usually wire up my electric gadgets to work. Unhappily, my old Rotel RT-950BX FM tuner collapsed today. I think it might be a corroded connection on the 300 ohm Aerial, but really, I don't know.
Investigations ongoing, but I have a temporary fix. I have a DAB 1 tuner also. DAB 2 might be preferable, but I can live with it.
Found a suitable cable:
Order happily restored on DAB. Back on BBC 5L!
https://www.bbc.co.uk/sounds/play/live:bbc_radio_five_live
They don't teach that in school! It's a gift!
https://en.wikipedia.org/wiki/QED:_The_Strange_Theory_of_Light_and_Matter
I can usually wire up my electric gadgets to work. Unhappily, my old Rotel RT-950BX FM tuner collapsed today. I think it might be a corroded connection on the 300 ohm Aerial, but really, I don't know.
Investigations ongoing, but I have a temporary fix. I have a DAB 1 tuner also. DAB 2 might be preferable, but I can live with it.
Found a suitable cable:
Order happily restored on DAB. Back on BBC 5L!
https://www.bbc.co.uk/sounds/play/live:bbc_radio_five_live
They don't teach that in school! It's a gift!
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OIII filters make use of absorption / forbidden lines in it's spectrum. When a photo is taken this means that the image of spectrum captured is black. In practice significantly blacker than other light that slips through the filer or due to ccd noise etc. When actual photo's are produced the degree of blackness is converted to some colour. Lot's of astro photo's use the same technique. Filters and chosen colours to represent them.
The telescope used may well have cost £8k+ The larger one used to confirm, rather a lot more,
The telescope used may well have cost £8k+ The larger one used to confirm, rather a lot more,