Apparently the total energy output of the cosmos is 4 × 10^69 Joules/second and that's been going on for 4.41^17 seconds and as far as we know, this will continue for at least another 4.41^17 seconds.
Some say the total energy of the universe is 0 (zero), so in the spirit of genuine enquiry, I'd like to know where all that energy has gone, and where it will go in the future? I get roughly 4 x 10^103 joules since the cosmos began with the BB 13.8 billion yrs ago.
Some say the total energy of the universe is 0 (zero), so in the spirit of genuine enquiry, I'd like to know where all that energy has gone, and where it will go in the future? I get roughly 4 x 10^103 joules since the cosmos began with the BB 13.8 billion yrs ago.
Since it takes positive energy to separate two pieces of matter, gravity must be using negative energy to pull them together.
This negative gravitational energy exactly cancels the positive energy represented by the matter, so the total energy of the universe is zero.
I read this here: https://www.livescience.com/33129-total-energy-universe-zero.html
But I'm not convinced! 😉
Neither am I. According to some, the vacuum energy density is c. 10^80 joules/m^3 (so more than the entire observable universe). Just as confusing and unlikely as a zero-energy universe - or a universe in which energy is not conserved.
But back to my question where has all the universe's energy gone and going?
But back to my question where has all the universe's energy gone and going?
This is an alternative explanation to the zero energy one I proffered above:
The high-grade energy currently being released by stars like the Sun will spread throughout the Universe.
The high-grade energy will become useless low-grade energy, but the total energy will remain the same.
Looks like Jeeves and Wooster in the nifty two-seater overtaking Aunt Agatha.
I am deep into Quantum Field Theory at the moment, after a good session reading Sean Carroll this afternoon, and I can tell you it is strange stuff indeed. Renormalization has me scratching my head, but I expect it will all sink in after a good nights sleep.
According to the experts, the Nova should happen at (Stardate?) 2024.4 +/- 0.3. This means we have only 7 weeks to stay within error. Also it is crucial to get it on the first day for maximum brightness.
https://www.aavso.org/news/t-crb-pre-eruption-dip
As @benb mentioned, this CNN news website has a thorough explanation of what we are excited about:
https://edition.cnn.com/2024/06/11/science/nova-new-star-nasa-scn/index.html
Tonight's snap from the darker back garden was quite straightforward. 30 seconds, 18mm (equivalent to 27mm on full frame), f3.5 tripod mount DSLR.
JPG compression takes a bit away, especially on colours. The bright star bottom right is Arcturus, which is easily found by following the tail of the Big Bear.
What we are patiently waiting for, ( How Long, Oh Lord, How Long? 🙄 ) is something resembling this:
Maybe tomorrow! 😎
I am deep into Quantum Field Theory at the moment, after a good session reading Sean Carroll this afternoon, and I can tell you it is strange stuff indeed. Renormalization has me scratching my head, but I expect it will all sink in after a good nights sleep.
According to the experts, the Nova should happen at (Stardate?) 2024.4 +/- 0.3. This means we have only 7 weeks to stay within error. Also it is crucial to get it on the first day for maximum brightness.
https://www.aavso.org/news/t-crb-pre-eruption-dip
As @benb mentioned, this CNN news website has a thorough explanation of what we are excited about:
https://edition.cnn.com/2024/06/11/science/nova-new-star-nasa-scn/index.html
Tonight's snap from the darker back garden was quite straightforward. 30 seconds, 18mm (equivalent to 27mm on full frame), f3.5 tripod mount DSLR.
JPG compression takes a bit away, especially on colours. The bright star bottom right is Arcturus, which is easily found by following the tail of the Big Bear.
What we are patiently waiting for, ( How Long, Oh Lord, How Long? 🙄 ) is something resembling this:
Maybe tomorrow! 😎
You're in good company, as I read (see link at bottom) that Richard Feynman regarded renormalization as mathematical hocus-pocus!
Apparently, renormalization involves carefully concealing infinite quantities in order to sidestep bogus predictions in quantum electrodynamics (QED).
Today, Feynman’s "hocus-pocus" has become as ubiquitous in physics as calculus.
Here's a non-mathematical look at what's behind it all: https://www.quantamagazine.org/how-renormalization-saved-particle-physics-20200917/
No useful progress on the Sean Carroll book today with Quantum Field Theory, so I went in a different direction. Freeman Dyson is considered to have knocked QED into respectability with the observation that the pioneers Feynman, Schwinger and Tomonaga were essentially doing the same thing in different ways:
The problem with even simple things like electrons is they interact with an electric field that itself fluctuates. The wretched Quantum at work!
An electron is interacting with a shield of virtual particles (electron-postron virtual pairs) that make it all very tricky to calculate.
So he came up with the Dyson Equation that sort of ties the different QED theories together into one whole:
No, I don't understand the maths either, but it uses old-time Green's Functions which IIRC, relate what goes on inside a sphere to what you measure on the surface.
There is an amazing series of 5 minute excerpts on YouTube from an interview with Freeman in his old age about all his adventures at Cornell, Caltech and Princeton with everybody important in High Energy Physics,
including Oppenheimer and all the usual suspects. Amazing guy! And explains things simply.
On Feynman:
On QED solutions:
There is some stuff about the Lamb Shift too, which was interesting since everybody loves the Hydrogen Atom. The man even evaluated Adaptive Optics for the military, though we know it better now as to why big earth-bound telescopes on Mauna Kea, Hawaii have sodium lasers.
Almost total cloud, so I have given up Nova astronomy for tonight. Too cold too!
Best, Steve.
The problem with even simple things like electrons is they interact with an electric field that itself fluctuates. The wretched Quantum at work!
An electron is interacting with a shield of virtual particles (electron-postron virtual pairs) that make it all very tricky to calculate.
So he came up with the Dyson Equation that sort of ties the different QED theories together into one whole:
No, I don't understand the maths either, but it uses old-time Green's Functions which IIRC, relate what goes on inside a sphere to what you measure on the surface.
There is an amazing series of 5 minute excerpts on YouTube from an interview with Freeman in his old age about all his adventures at Cornell, Caltech and Princeton with everybody important in High Energy Physics,
including Oppenheimer and all the usual suspects. Amazing guy! And explains things simply.
On Feynman:
On QED solutions:
There is some stuff about the Lamb Shift too, which was interesting since everybody loves the Hydrogen Atom. The man even evaluated Adaptive Optics for the military, though we know it better now as to why big earth-bound telescopes on Mauna Kea, Hawaii have sodium lasers.
Almost total cloud, so I have given up Nova astronomy for tonight. Too cold too!
Best, Steve.
Aha! I was nagged by the thought that "Sod's Law" would make the Nova go off tonight... 🙁
A gap in the clouds! Phew, can sleep tonight. I am persistent, you see. What we call "A Safe Pair of Hands" in cricket parlance. 😀
A gap in the clouds! Phew, can sleep tonight. I am persistent, you see. What we call "A Safe Pair of Hands" in cricket parlance. 😀
Nice Feynman diagrams! I read that "the Dyson equation determines the renormalized Green's function".
It seems we're dealing with 'self-energy' or
'Self-energy' is explained here: https://en.wikipedia.org/wiki/Self-energy
In quantum field theory, virtual particles are termed 'off mass shell' because they do not satisfy the energy–momentum relation; real exchange particles do satisfy this relation and are termed 'on mass shell'.
The 'Lamb shift' is a slight shift of a spectral line in the hydrogen spectrum.
The experimental measurement of the Lamb shift verified the theoretical calculations made with QED which predicted the photon exchange model of the electromagnetic force.
Learning all the time! 😎
If I understand it correctly, a virtual particle - say a photon in this case - is one that is emitted by an atom but them immediately re absorbed by the same atom?
In the case of the Lamb shift, virtual photons interact with the electron as it orbits the hydrogen nucleus.
Virtual photons are created through vacuum energy fluctuations.
Virtual photons are created through vacuum energy fluctuations.
If you prefer, you may think of virtual photons as 'temporary' fluctuations in the electromagnetic field.
The uncertainty principle allows the virtual particles to spontaneously emerge from vacuum at short time and space ranges.
Consider the Casimir effect which arises due to the existence of virtual photons in the vacuum.
The uncertainty principle allows the virtual particles to spontaneously emerge from vacuum at short time and space ranges.
Consider the Casimir effect which arises due to the existence of virtual photons in the vacuum.
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So because things are quantised at the smallest levels, matter (particles) bounce in and out of existence? As an analogy its almost like noise induced LSB fluctuations in an ADC.
It is virtual particles that "bounce in and out of existence".
Quantum mechanics allows a particle to become a pair of virtual particles which quickly rejoin into the original particle as if they had never been there.
The same quantum mechanics allows a photon to spend some time as a virtual electron plus its antiparticle, the virtual positron.
While they briefly exist in 'our world', these virtual particles can interact with other particles.
As @system7 said above with respect to the Dyson equation, "An electron is interacting with a shield of virtual particles (electron-positron virtual pairs)".
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I made an edit above because I asked myself, "Do virtual particles have the same properties as ordinary particles?".
A quick google reveals, "Virtual particles do not necessarily carry the same mass as the corresponding real particle, although they always conserve energy and momentum. The longer the virtual particle exists, the closer its characteristics come to those of ordinary particles".
https://clearlyexplained.com/virtual-particles/index.html
I read that there are arguments for the existence of virtual particles and arguments that virtual particles are as real as others.
Best I bow out now!
A quick google reveals, "Virtual particles do not necessarily carry the same mass as the corresponding real particle, although they always conserve energy and momentum. The longer the virtual particle exists, the closer its characteristics come to those of ordinary particles".
https://clearlyexplained.com/virtual-particles/index.html
I read that there are arguments for the existence of virtual particles and arguments that virtual particles are as real as others.
Best I bow out now!
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