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davieG

Technology, Science and the Environment.

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6 hours ago, String fellow said:

At last, an explanation of why Muons wobble around so much! In fact, experiments carried out by Brookhaven National Laboratory in 2006 involving the Muons found that they exhibited behaviour as a result of physics beyond the Standard Model, implying that some unknown fifth force might be causing it.   

Considering we still don't know exactly what is responsible for the greater part of all gravitational force, there's still a lot that we need to find out, I think.

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There have always been gaps in the Standard Model and we knew it wasn't the whole story. The LHC was specifically designed to find these heavier, more energetic fundamental particles. Hopefully this muon is the next step. 

 

I'd been reading about Loop Quantum Gravity recently, as a quantum understanding of gravity is what we really need to develop a unified theory. That  sounds really interesting as Einsteins equations pop right out of it from the maths apparently. Ironically string theory looks a busted flush IMO (suck it Sheldon). 

 

I also read an article last week that suggests Dark Energy is actually a magnetic force originating from Dark Matter particles. Their simulations show the universe expanding in exactly the same way without Dark Energy. 

 

https://scitechdaily.com/new-model-raises-doubt-about-the-composition-of-70-of-our-universe-dark-energy-may-simply-not-exist/amp/

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1 hour ago, The Bear said:

There have always been gaps in the Standard Model and we knew it wasn't the whole story. The LHC was specifically designed to find these heavier, more energetic fundamental particles. Hopefully this muon is the next step. 

 

I'd been reading about Loop Quantum Gravity recently, as a quantum understanding of gravity is what we really need to develop a unified theory. That  sounds really interesting as Einsteins equations pop right out of it from the maths apparently. Ironically string theory looks a busted flush IMO (suck it Sheldon). 

 

I also read an article last week that suggests Dark Energy is actually a magnetic force originating from Dark Matter particles. Their simulations show the universe expanding in exactly the same way without Dark Energy. 

 

https://scitechdaily.com/new-model-raises-doubt-about-the-composition-of-70-of-our-universe-dark-energy-may-simply-not-exist/amp/

I didn't even know this was going on! Evidently need to do more reading.

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2 hours ago, The Bear said:

There have always been gaps in the Standard Model and we knew it wasn't the whole story. The LHC was specifically designed to find these heavier, more energetic fundamental particles. Hopefully this muon is the next step. 

 

I'd been reading about Loop Quantum Gravity recently, as a quantum understanding of gravity is what we really need to develop a unified theory. That  sounds really interesting as Einsteins equations pop right out of it from the maths apparently. Ironically string theory looks a busted flush IMO (suck it Sheldon). 

 

I also read an article last week that suggests Dark Energy is actually a magnetic force originating from Dark Matter particles. Their simulations show the universe expanding in exactly the same way without Dark Energy. 

 

https://scitechdaily.com/new-model-raises-doubt-about-the-composition-of-70-of-our-universe-dark-energy-may-simply-not-exist/amp/

I've no idea what Loop Quantum Gravity is, but gravity as a force seems paradoxical, because an accelerometer will read zero when falling towards Earth, implying that it's not accelerating. Therefore it's not experiencing any applied force.    

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5 minutes ago, String fellow said:

I've no idea what Loop Quantum Gravity is, but gravity as a force seems paradoxical, because an accelerometer will read zero when falling towards Earth, implying that it's not accelerating. Therefore it's not experiencing any applied force.    

I'm no expert on this, but as I understand it gravity isn't really a force in itself, more the effect on bodies of the curves in space/time (caused by the mass of other bodies).

Could have got that totally wrong, but it makes a kind of sense to me. 

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I'm no expert either, just interested in the physics. With any rotating two-body system in space, there are 5 so-called Lagrange points, where the forces of gravity and the centripetal forces of the bodies all cancel out. These good places to park satellites, as they are points where the competing forces are in either stable or unstable equilibrium. However, I've yet to find any illustration which shows how space-time is curved at these points. 

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49 minutes ago, String fellow said:

I've no idea what Loop Quantum Gravity is, but gravity as a force seems paradoxical, because an accelerometer will read zero when falling towards Earth, implying that it's not accelerating. Therefore it's not experiencing any applied force.    

That's only because it measures acceleration purely in its own rest frame and so the force of gravity is offset, but not no longer there.

 

39 minutes ago, Stoopid said:

I'm no expert on this, but as I understand it gravity isn't really a force in itself, more the effect on bodies of the curves in space/time (caused by the mass of other bodies).

Could have got that totally wrong, but it makes a kind of sense to me. 

Gravity is a force by definition, however it is definitely different to the others we know of and we still haven't exactly pinned down how exactly it operates (particularly how it seems to act over vast distances instantaneously).

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13 minutes ago, leicsmac said:

That's only because it measures acceleration purely in its own rest frame and so the force of gravity is offset, but not no longer there.

 

Gravity is a force by definition, however it is definitely different to the others we know of and we still haven't exactly pinned down how exactly it operates (particularly how it seems to act over vast distances instantaneously).

There seems to be a bit of a mystery about it then? Kind of blows my mind a bit that so much is still basically unknown - dark matter/energy even gravity itself as you point out. 

In another way it's quite comforting. 

I mean, we've come a long way, no doubt. But the deepest questions about the universe and our place in it remain stubbornly out of reach. 

I quite like that, in an odd way. 

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2 minutes ago, Stoopid said:

There seems to be a bit of a mystery about it then? Kind of blows my mind a bit that so much is still basically unknown - dark matter/energy even gravity itself as you point out. 

In another way it's quite comforting. 

I mean, we've come a long way, no doubt. But the deepest questions about the universe and our place in it remain stubbornly out of reach. 

I quite like that, in an odd way. 

I think it was Professor Hawking that said finding out simply everything would be impossible because doing so would also dictate whether we would be successful or not!  Paradoxical.

 

Tbh I'd like us to learn more about the universe, though. The more we learn, the more we may be able to use that knowledge to continue surviving. That's why I have little time for folks who dismiss "theoretical" research because it has no "practical" (read £££) applications. Knowing as much as we can could make a critical difference in the future, even if it doesn't do so immediately.

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1 minute ago, leicsmac said:

I think it was Professor Hawking that said finding out simply everything would be impossible because doing so would also dictate whether we would be successful or not!  Paradoxical.

 

Tbh I'd like us to learn more about the universe, though. The more we learn, the more we may be able to use that knowledge to continue surviving. That's why I have little time for folks who dismiss "theoretical" research because it has no "practical" (read £££) applications. Knowing as much as we can could make a critical difference in the future, even if it doesn't do so immediately.

I agree with you. Not only is it fascinating in itself, but quite often it turns out to have practical applications anyway - often in ways that are quite unexpected or in future developments in other fields. 

 

 

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If you jump from a tall building, you feel weightless, as if in outer space where gravity is very low. The only force you feel is when hitting the ground, which must therefore be providing an upward force. Furthermore, as you are falling, everything round you is accelerating upwards, again providing evidence that the force of gravity, or whatever it is, is acting upwards, not downwards. Basically, things fall down when the force holding them up is removed.   

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13 minutes ago, String fellow said:

If you jump from a tall building, you feel weightless, as if in outer space where gravity is very low. The only force you feel is when hitting the ground, which must therefore be providing an upward force. Furthermore, as you are falling, everything round you is accelerating upwards, again providing evidence that the force of gravity, or whatever it is, is acting upwards, not downwards. Basically, things fall down when the force holding them up is removed.   

Only from your own inertial frame of reference. An outside observer would simply see you falling at standard gravitational acceleration and wouldn't see the buildings accelerating at all.

 

That's why considering the frame of reference is so important - from an observational perspective, gravity is always an attractive rather than a repulsive force; that's what makes it unique.

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Einstein showed very nicely how everything is relative, and you can't describe anything without a specific reference frame. Only light ignores that by being identical for every observer. 

 

As for a curved spacetime model for legrange points, I'd assume it'd look something like a tiny flat bit surrounded by space curving down and away on all sides. 

 

Though I had read a while back on Quora (and as such can't remember the details) that curved space is just a clumsy metaphor for what it actually going on. 

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29 minutes ago, The Bear said:

Einstein showed very nicely how everything is relative, and you can't describe anything without a specific reference frame. Only light ignores that by being identical for every observer. 

 

As for a curved spacetime model for legrange points, I'd assume it'd look something like a tiny flat bit surrounded by space curving down and away on all sides

 

Though I had read a while back on Quora (and as such can't remember the details) that curved space is just a clumsy metaphor for what it actually going on. 

That's more or less how I'd envisaged them. However, the centripetal force is also a factor to complicate things. (I've had a fascination with these points in space for a long while. There are also 5 of them in the Earth-Moon system.)

As regards gravity, it's a moot point whether a man standing up is pushing down on the ground giving the Earth weight, or whether the Earth is pushing up on the man giving him weight. As for it only being an attractive force, that seems to be a given if mass itself can only be positive. 

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22 minutes ago, String fellow said:

That's more or less how I'd envisaged them. However, the centripetal force is also a factor to complicate things. (I've had a fascination with these points in space for a long while. There are also 5 of them in the Earth-Moon system.)

As regards gravity, it's a moot point whether a man standing up is pushing down on the ground giving the Earth weight, or whether the Earth is pushing up on the man giving him weight. As for it only being an attractive force, that seems to be a given if mass itself can only be positive. 

Apologies if I appeared overly confrontational there btw - not my intent.

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4 minutes ago, leicsmac said:

Apologies if I appeared overly confrontational there btw - not my intent.

No worries. I'm always happy to engage in philosophical discussions on a wide range of subjects, and always appreciate your flagging up of science news.

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1 minute ago, Dahnsouff said:

That’s scary, thrilling, concerning, heartening, mind-blowing and needed, all in fairly equal measures.  

Interesting!

 

Would you care to elaborate on the scary and concerning parts? I'm curious.

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9 minutes ago, leicsmac said:

Interesting!

 

Would you care to elaborate on the scary and concerning parts? I'm curious.

I would have thought that what is basically creating a star is fairly scary, especially considering what happens to a star when it runs out of fuel. 

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14 minutes ago, leicsmac said:

Interesting!

 

Would you care to elaborate on the scary and concerning parts? I'm curious.

Just because I thought containment was a prime requirement and it had proven elusive until this point, and nine years seems quick to ensure its suitability. 

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6 minutes ago, yorkie1999 said:

I would have thought that what is basically creating a star is fairly scary, especially considering what happens to a star when it runs out of fuel. 

 

1 minute ago, Dahnsouff said:

Just because I thought containment was a prime requirement and it had proven elusive until this point, and nine years seems quick to ensure its suitability. 

Safety and containment concerns are in fact far less than for fission reactors.

 

All fusion reactions require a steady stream of fuel, and when they no longer have that, they simply stop - they don't go "prompt critical" in the way a fission reactor might if things get unstable. When a star runs out of hydrogen fuel, it simply changes to carbon fusion instead (as well as hydrogen fusion through a different process), it doesn't run out of fuel per se - a bit different to a fusion reactor.

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