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Mike Hewson
Mike Hewson
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hadron wrote: .... to

hadron wrote:

.... to realize just how insignificant this planet is in the vast realm of space.

I think all of the Apollo astronauts, and many others since of course, have said pretty much the same thing. Indeed most/all astronauts who have flown into space find it a life changing experience.

My quick research shows we now have five living Apollo astronauts that went into space. In fact we have no living Apollo astronauts that didn't get to space.

  • Jim Lovell (Apollo 8 & 13) - 96 years old
  • Buzz Aldrin (Apollo 11) - 94 years old
  • David Scott (Apollo 9 & 15) - 91 years old
  • Charles Duke (Apollo 16) - 88 years old
  • Harrison Schmitt (Apollo 17) - 88 years old

Jim Lovell went to the Moon twice but never landed, though he named a mountain after his wife Marilyn. The other four did step on the Moon. Buzz Aldrin, upon stepping onto the Moon, called the moonscape "magnificent desolation". Aren't we going back there 'soon' via Artemis ? 

hadron wrote:

The place to be is, and has been since 1982, in quantum reality and quantum philosophy. That was when Alain Aspect's test of Bell's theorem showed the world that classical reality isn't real at all.

We haven't really come very far since then, but I am sure we are on the verge of a paradigm shift in our thinking.

Fair enough. I think every now and again about entanglement etc and still can't "get it" in my guts, probably never will. Your thinking can be dominated by the scale that you live at, and of course by your life's learning.

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

hadron
hadron
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Mike Hewson wrote: hadron

Mike Hewson wrote:

hadron wrote:

.... to realize just how insignificant this planet is in the vast realm of space.

I think all of the Apollo astronauts, and many others since of course, have said pretty much the same thing. Indeed most/all astronauts who have flown into space find it a life changing experience.

My quick research shows we now have five living Apollo astronauts that went into space. In fact we have no living Apollo astronauts that didn't get to space.

  • Jim Lovell (Apollo 8 & 13) - 96 years old
  • Buzz Aldrin (Apollo 11) - 94 years old
  • David Scott (Apollo 9 & 15) - 91 years old
  • Charles Duke (Apollo 16) - 88 years old
  • Harrison Schmitt (Apollo 17) - 88 years old

Jim Lovell went to the Moon twice but never landed, though he named a mountain after his wife Marilyn. The other four did step on the Moon. Buzz Aldrin, upon stepping onto the Moon, called the moonscape "magnificent desolation". Aren't we going back there 'soon' via Artemis ?

Have you ever watched From the Earth to the Moon? Highly recommended. https://en.wikipedia.org/wiki/From_the_Earth_to_the_Moon_(miniseries)

On the Apollo 15 mission, one very notable event was when David Scott and Jim Irwin stood on the rim of an impact crater, and methodically described the local geology in considerable detail. I believe it was David Scott who did that, and he spoke like a professional geologist. He wasn't, of course, but he was trained by one. Harrison Schmitt, who has a PhD in geology, was instrumental in getting the astronauts out of the classroom and into the field for some proper training in geology.

Another payoff from that training was the discovery and recovery of a sample now known as the "Genesis Rock", once believed to be from the primordial lunar crust. It isn't, but it is one of the oldest rock samples ever collected by the Apollo program, dated at 4.1 billion years old.

Mike Hewson wrote:
hadron wrote:

The place to be is, and has been since 1982, in quantum reality and quantum philosophy. That was when Alain Aspect's test of Bell's theorem showed the world that classical reality isn't real at all.

We haven't really come very far since then, but I am sure we are on the verge of a paradigm shift in our thinking.

Fair enough. I think every now and again about entanglement etc and still can't "get it" in my guts, probably never will. Your thinking can be dominated by the scale that you live at, and of course by your life's learning

Well, don't think about it too hard; you'll only give yourself a massive headache lol. Entanglement is a strictly quantum thing, but we think in classical terms. Thus we have this (probably wrong) notion that two (or more) entangled quantum particles (wave functions) are somehow connected together, but are still separate things. To me, however, entanglement simply means that those particles are describable somehow by a single wave function -- one that continues to exist until part of that wave function interacts with something else (eg. in an experimental observation), thus destroying the old entanglement and creating a new one.

Not very well developed, certainly, but that is as far as I can get without giving myself a massive headache lol.

Tom M
Tom M
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https://www.livescience.com/s

https://www.livescience.com/space/astronomy/space-photo-of-the-week-james-webb-and-chandra-telescopes-spot-a-lighthouse-pointed-at-earth

The Article said the magic word "pulsar".

:)

A Proud member of the O.F.A.  (Old Farts Association).  Be well, do good work, and keep in touch.® (Garrison Keillor)

Tom M
Tom M
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https://phys.org/news/2024-06

https://phys.org/news/2024-06-einstein-telescope-era-astronomy.html

More waving detection.

:)

1,000 times more sensitive.

A Proud member of the O.F.A.  (Old Farts Association).  Be well, do good work, and keep in touch.® (Garrison Keillor)

Tom M
Tom M
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https://www.astronomy.com/sci

https://www.astronomy.com/science/merging-black-holes/

A Proud member of the O.F.A.  (Old Farts Association).  Be well, do good work, and keep in touch.® (Garrison Keillor)

hadron
hadron
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Tom M

Tom M wrote:

https://phys.org/news/2024-06-einstein-telescope-era-astronomy.html

More waving detection.

:)

1,000 times more sensitive.

A 3-laser interferometer; previous detectors have been Michelson interferometers, like the ones you probably remember from first-year uni ;)

As I was reading the article, I couldn't help but wonder, what would the 19th century giants of optics -- Young, Fresnel, Fraunhofer, Michelson and more -- think if they could see what has become of all their effort?

hadron
hadron
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Tom M

Why do most cosmologists insist on believing that Riemannian geometry is the final word in gravitation theory? Certainly it is the correct post-Newtonian approximation to a complete theory of classical gravitation, but that most assuredly does not mean it is the final word. Indeed, there are many examples of observations which suggest the opposite -- that it is merely the first step along a long path.

The first example is the deflection of stellar light. In 1919, Eddington showed that there was such an effect, during his eclipse expedition. What was not possible, however, was to show that the observed effect was precisely that predicted by Einstein. Oh, it was tantalizingly close, to be sure, determining the exact magnitude of the effect depends highly on where the actual size and shape of the sun -- that is, where is the exact location of the edge of the solar disc, and what is the oblateness of the rotating sun?

Next is the precession of the planetary perihelia. Calculations of these is not an easy task, because a) Newtonian perturbations dwarf all other effects by at least an order of magnitude, and b) the magnitude of the effect now also includes the oblateness of the planet itself, which turns out to be far more important than solar oblateness. Every planet began as a ball of molten rock, so there is no reason to believe any of them are even close to being spherical, even if they are balls of solid rock today.

I have not done active research for a great many years, so the latest figures I have for both of these are quite old. In 1982, for example, the difference between the predicted and observed relativistic correction to Mercury's precession gave only a 3-σ confidence. Experimental verification of a predicted result requires 5 or better. So, I have to ask if anyone knows of recent results that give a better confidence?

But we are not done. Enter galactic rotation, stage right. General relativity alone is quite incapable of describing the rotations of the vast majority of galaxies. What was the "final" answer to that problem? Dark matter. This is an ad hoc addition to gravitation theory for the sole purpose of explaining all those pesky problematic galactic rotations -- but there are a few galaxies out there for which relativity alone is sufficient to describe their rotation. In my mind, dark matter is nothing but a deus ex machina hauled out to make the script fit the plot -- or, as Einstein himself once put it, "drilling in places where drilling is easy."

This is already getting very long, so I am not going to describe alternative theories, but rather direct you to a couple of places where such theories have been proposed. Notably, these include the work of John Moffat and Joao Maguiejo who independently derived a theory in which the speed of light is variable[1]. Of all of these proposals, my favourite at this time is the scalar-tensor-vector theory first proposed by Moffat and others in 2006. On the cosmic scale, it appears to explain such things as galactic rotations and gravitational lensing without the need for dark matter, while, on the small scale, eg. our solar system, it predicts no observable deviation from special relativity.

1. It is interesting to note that Magueijo's paper was published in 1998, in the same journal which only 5 years earlier, had rejected Moffat's original paper.

Tom M
Tom M
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https://www.cnn.com/2024/06/1

https://www.cnn.com/2024/06/17/science/black-holes-dark-matter-scn/index.html

 

A Proud member of the O.F.A.  (Old Farts Association).  Be well, do good work, and keep in touch.® (Garrison Keillor)

cecht
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Interesting.Here is the

Interesting.

Here is the original article that the CNN story was based on:

https://news.mit.edu/2024/exotic-black-holes-could-be-dark-matter-byproduct-0606

and the published paper:

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.132.231402

Ideas are not fixed, nor should they be; we live in model-dependent reality.

Mike
Mike
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Much appreciate all these

Much appreciate all these updates on interesting news.   Thank you all for the contributions.

/Mike

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