I shouldn't worry about it. Those "supercharged rhinos" are purely hypothetical!
And if anyone doubts the veracity of the Lunar Reconnaissance Orbiter (LRO) image:
The LRO may have been launched by NASA, but the camera and the interpretation of the images are under the control of non-affiliated academic groups which are not located in the US and are not funded by the US government - such as the German Aerospace Center, Berlin.
All six LRO Apollo landing sites images here: https://skyandtelescope.org/observi...how-to-see-all-six-apollo-moon-landing-sites/
LOOKALIKES:
Mixing fact and fiction, I wonder if you noticed, as I did, the extraordinary resemblance between fictitious astronaut Apollo 11 Michael Collins and the Nobel Physics Laureate, Doctor Sheldon Lee Cooper?
I wonder if they are related?
Of course, you will remember the early episode of The Big Bang Theory when the boys are up on the roof of the apartment block recreating that test of Einstein's Gravity Theory, the LRRR from Apollo 11 by firing a Laser at The Moon.
It is essentially a giant bicycle reflector designed to return a Laser beam to Earth with great precision. It was used to test the dubious (IMO) Brans-Dicke Theory of Gravity:
https://en.wikipedia.org/wiki/Brans–Dicke_theory
Amusingly, this very accurate forerunner to GPS uncovered errors in Earth map making!
https://en.wikipedia.org/wiki/Laser_Ranging_Retroreflector
In The Big Bang Theory episode, Penny realises her latest muscly flame is dumber than a fence post compared to Leonard.
He has no idea where or what The Moon is...
Mixing fact and fiction, I wonder if you noticed, as I did, the extraordinary resemblance between fictitious astronaut Apollo 11 Michael Collins and the Nobel Physics Laureate, Doctor Sheldon Lee Cooper?
I wonder if they are related?
Of course, you will remember the early episode of The Big Bang Theory when the boys are up on the roof of the apartment block recreating that test of Einstein's Gravity Theory, the LRRR from Apollo 11 by firing a Laser at The Moon.
It is essentially a giant bicycle reflector designed to return a Laser beam to Earth with great precision. It was used to test the dubious (IMO) Brans-Dicke Theory of Gravity:
https://en.wikipedia.org/wiki/Brans–Dicke_theory
Amusingly, this very accurate forerunner to GPS uncovered errors in Earth map making!
https://en.wikipedia.org/wiki/Laser_Ranging_Retroreflector
In The Big Bang Theory episode, Penny realises her latest muscly flame is dumber than a fence post compared to Leonard.
He has no idea where or what The Moon is...
The episode of TBBT that I referred to was Season 3, #23. "The Lunar Excitation".
In which Raj surreptitiously matches Sheldon to Amy Farrah-Fowler on a dating site by uploading his (unusual) profile.
Zack asks Leonard if he can guarantee his Laser won't cause The Moon to explode! Really....
I really think that understanding the early microseconds of the Big Bang is a bit of a waste of time. Maybe just me... and Freeman Dyson!
No, don't watch it. I can tell you that he thinks integrating Quantum Mechanics and Gravity is not necessary. I certainly won't be trying to do this today. The Graviton, if it exists, is so light that it is beyond our measuring ability.
It must also be huge in spatial terms, being so much lighter than an electron. To go from LIGO measurements to individual Gravitons is the order of 10^37!
I find Neutrinos far more interesting. Why, 90% of the outpouring energy of a Supernova is in Neutrinos. I expect T Nova Corona Borealis might cause the odd blip in those detectors miles underground too.
Last night's picture:
Here we can see in the bottom LH corner, Alpha Ophiucus and and Alpha Hercules. Ophiucus is the 13th sign of the Zodiac. Between Scorpio and Sagittarius.
It is interesting to me that these two Alphas here are the closest in the Night Sky. This is a fact that may serve you well if you are ever asked this on a TV quiz show, like University Challenge.
In which Raj surreptitiously matches Sheldon to Amy Farrah-Fowler on a dating site by uploading his (unusual) profile.
Zack asks Leonard if he can guarantee his Laser won't cause The Moon to explode! Really....
I really think that understanding the early microseconds of the Big Bang is a bit of a waste of time. Maybe just me... and Freeman Dyson!
No, don't watch it. I can tell you that he thinks integrating Quantum Mechanics and Gravity is not necessary. I certainly won't be trying to do this today. The Graviton, if it exists, is so light that it is beyond our measuring ability.
It must also be huge in spatial terms, being so much lighter than an electron. To go from LIGO measurements to individual Gravitons is the order of 10^37!
I find Neutrinos far more interesting. Why, 90% of the outpouring energy of a Supernova is in Neutrinos. I expect T Nova Corona Borealis might cause the odd blip in those detectors miles underground too.
Last night's picture:
Here we can see in the bottom LH corner, Alpha Ophiucus and and Alpha Hercules. Ophiucus is the 13th sign of the Zodiac. Between Scorpio and Sagittarius.
It is interesting to me that these two Alphas here are the closest in the Night Sky. This is a fact that may serve you well if you are ever asked this on a TV quiz show, like University Challenge.
I read that a graviton detector would need to be of the mass of Jupiter and placed near a potential strong source of gravitons such as a neutron star.
I also read that a photon of the same energy as the rest energy of a graviton would have a wavelength of around 1.6 light years!
The corresponding photon wavelength for an electron is only ~2.4 x 10^-12 m.
It was Stephen Weinberg that showed it was possible to interchange fields and particles in the same way we do for light to describe any force acting at a distance through a vacuum - hence the graviton thing. Since gravity is such a week force compared to the other three, if makes sense it would be very light. Whether it exists is up for debate. What would Einstein make of it?
Ethan explains how quantum fields produce particles:
https://www.forbes.com/sites/starts...ethan-how-do-quantum-fields-create-particles/
He's not wrong when he says it's "a bit tricky"!
I got on pretty well with my Sean Carroll book "Quanta and Fields" today. I am not sufficiently understanding to explain it all at this stage, but some gleanings:
The Lagrangian is actually the "Lagrangian Density" which is an integral over a path.
There exist Photon Fields and Electron/Positron Fields. Maxwell didn't know about electrons specifically.
You move from Scalar to Vector Fields. Add in some Group Theory and Emmy Noether.
You then add complex values to the vectors, which makes them Tensors.
You then consider Gauge Symmetries being conserved quantities when things move around.
Electromagnetic is U(1), Weak Force is SU(2), and Quarks and Gluons are SU(3) and have different Gauge symmetries.
Expressed overall as SU(3)×SU(2)×U(1) in the Standard Model.
https://en.wikipedia.org/wiki/Standard_Model
It's all quite brilliant, explaining what does and doesn't have mass and whether they are short or long range. The Graviton is speculative, but must be massless and long range.
And the Higgs is another stretch of the Theory which is not strictly needed in electromagnetism.
I am impressed with it all. It's just Groups and Tensors I am weak on. Otherwise my name would be Dick Feynman.
Monday 24 June, 2100 BST, we have a Nova related Webcast to watch:
https://www.virtualtelescope.eu/webtv/
An ASTEROID. Pallas.
https://en.wikipedia.org/wiki/2_Pallas
All very interesting.
The Lagrangian is actually the "Lagrangian Density" which is an integral over a path.
There exist Photon Fields and Electron/Positron Fields. Maxwell didn't know about electrons specifically.
You move from Scalar to Vector Fields. Add in some Group Theory and Emmy Noether.
You then add complex values to the vectors, which makes them Tensors.
You then consider Gauge Symmetries being conserved quantities when things move around.
Electromagnetic is U(1), Weak Force is SU(2), and Quarks and Gluons are SU(3) and have different Gauge symmetries.
Expressed overall as SU(3)×SU(2)×U(1) in the Standard Model.
https://en.wikipedia.org/wiki/Standard_Model
It's all quite brilliant, explaining what does and doesn't have mass and whether they are short or long range. The Graviton is speculative, but must be massless and long range.
And the Higgs is another stretch of the Theory which is not strictly needed in electromagnetism.
I am impressed with it all. It's just Groups and Tensors I am weak on. Otherwise my name would be Dick Feynman.
Monday 24 June, 2100 BST, we have a Nova related Webcast to watch:
https://www.virtualtelescope.eu/webtv/
An ASTEROID. Pallas.
https://en.wikipedia.org/wiki/2_Pallas
All very interesting.
Sean Carroll has said that space is full of fields, “At every point in space, there’s dozens of little vibrating fields … when you look at the fields closely enough they resolve into individual particles.”
There are a lot of quantum fields, including one for every fundamental particle: an electron field, a photon field, many quark fields, a Higgs field, and so on.
You can picture particles as waves in their fields - electrons in the electron field, photons in the photon field, and so on.
It's how these fields interact with each other that is of significance. Accelerating electrons around on the electron field can shake the coupled photon field and generate the excitations that we call photons - like what happens in a light bulb or a laser.
Don't believe me? I read it here: https://www.bostonreview.net/articles/matthew-buckley-search-new-physics-cern-part-2/
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You could also imagine a scenario where there is just one field, but different forces (energy) couple differently to the field. I struggle to understand how if there’s all these different fields about, a photon can make it across the observable cosmos without getting bushwhacked along the way.
Lex Fridman poked fun at TP’s ‘creating fields to solve problems and quantising them when convenient’ (I paraphrase here).
Lex Fridman poked fun at TP’s ‘creating fields to solve problems and quantising them when convenient’ (I paraphrase here).
I do think that Quantum Fields need a lot of high level mathematics to understand! Lie Groups, Guage Symmetries, Spinors, you name it!
This stuff needs about 3 years postgraduate at least. And you can't explain it in two pages of "Ask Ethan" or anyone else.
I was out tonight with the camera. No. No Nova!
But I found a scintillating double in Cygnus, called Omicron 1.
You can see Cygnus, aka the Northern Cross in the bottom third below bright Vega with Gamma Draco looking bright at the top in that kite shaped head of the dragon. The line is an airplane...
In about 200,000 years, Vega will be the brightest star in the sky at Magnitude -1 and doubtless still be a regular Pole Star every 25,000 years. Sirius will have wandered away into the Southern Hemisphere and be much dimmer.
But the sleeping whopper is actually giant Type K orange Gamma Draco. 571 times the brightness of the Sun, it will be as bright as Sirius is now in 1.5M years and only 26 LY away.
Ah, yes. The Omicron 1 Cygnus (visual) Double which is about a third of the way up in the big picture on the left:
Gorgeous Yellow and Blue. I just happened to spot it using 55mm focal length, trying unsuccessfully to get The Milky Way in Cygnus in a picture.
I need darker skies than my street.
If I had a proper telescope, it would look like this:
https://bestdoubles.wordpress.com/2011/08/13/the-omega-ω-and-the-omicron-ο-of-cygnus-ο-1-and-ο-2-and-ω-1-and-ω-2-sh-755-and-sh-756/
Pleased with that.
This stuff needs about 3 years postgraduate at least. And you can't explain it in two pages of "Ask Ethan" or anyone else.
I was out tonight with the camera. No. No Nova!
But I found a scintillating double in Cygnus, called Omicron 1.
You can see Cygnus, aka the Northern Cross in the bottom third below bright Vega with Gamma Draco looking bright at the top in that kite shaped head of the dragon. The line is an airplane...
In about 200,000 years, Vega will be the brightest star in the sky at Magnitude -1 and doubtless still be a regular Pole Star every 25,000 years. Sirius will have wandered away into the Southern Hemisphere and be much dimmer.
But the sleeping whopper is actually giant Type K orange Gamma Draco. 571 times the brightness of the Sun, it will be as bright as Sirius is now in 1.5M years and only 26 LY away.
Ah, yes. The Omicron 1 Cygnus (visual) Double which is about a third of the way up in the big picture on the left:
Gorgeous Yellow and Blue. I just happened to spot it using 55mm focal length, trying unsuccessfully to get The Milky Way in Cygnus in a picture.
I need darker skies than my street.
If I had a proper telescope, it would look like this:
https://bestdoubles.wordpress.com/2011/08/13/the-omega-ω-and-the-omicron-ο-of-cygnus-ο-1-and-ο-2-and-ω-1-and-ω-2-sh-755-and-sh-756/
Pleased with that.
I was puzzling over my 15s, f5.6 55mm (eff 80 mm) ISO 400 picture of Omicron 1. I think the small format Nikon D60 is about 9M pixels, but the lens is clearly the limiting factor. Can I see the third star?
Windows Photoviewer got SOME promising pixels bottom right:
Shotwell in Linux did much the same, then automatically after 1 second anti-aliased it to fuzziness:
We are at the Heisenberg Limit of the Quanta here! Clearly I might try ISO 800 or 1600 and a shorter 4-8s exposure to reduce the trailing.
400 / f number = Optimal Exposure. Maybe 6 seconds. For another night!
Windows Photoviewer got SOME promising pixels bottom right:
Shotwell in Linux did much the same, then automatically after 1 second anti-aliased it to fuzziness:
We are at the Heisenberg Limit of the Quanta here! Clearly I might try ISO 800 or 1600 and a shorter 4-8s exposure to reduce the trailing.
400 / f number = Optimal Exposure. Maybe 6 seconds. For another night!
The following might help you up to speed on this Astronomy Lark:
Astronomers often say "Oh, Be A Fine Girl, Kiss Me". AKA "OBAFGKM".
In what context, I am not too sure...
The Greek alphabet should be ingrained on all Astronomers, and Quantum Mechanicists too:
I always find Zeta and Xi difficult to distinguish. But then my name isn't Plato.
Astronomers often say "Oh, Be A Fine Girl, Kiss Me". AKA "OBAFGKM".
In what context, I am not too sure...
The Greek alphabet should be ingrained on all Astronomers, and Quantum Mechanicists too:
I always find Zeta and Xi difficult to distinguish. But then my name isn't Plato.
Try using the highest ISO setting on your camera, but you really need a lens with a much shorter focal length in order to minimise star trails.
Try the "500 Rule": 500 / (Crop-Factor x Focal Length) = Ideal Shutter Speed
I believe the crop factor is 1.5 for your Nikon APS-C sensor.