A Collision at the Speed of Light

[symesie04]

58 minutes ago, IanL said:

You're confused because I didn't say if you had the infinite set of integers you can always add one more. Exactly the opposite in fact, if you can add one more it wasn't the infinite set. My point was that mathematically you can have two infinite sets, combine them and still have an infinite set. I was just illustrating that mathematical rules and what is possible in reality aren't necessarily the same thing.

Well i was just toying a bit and do get your point but as we are now on the subject i still have some issues with it. So the point being if you have a infinite number of positive integers and a infinite number of negative integers they can both exist and be added to still make a infinite number of integers? But surely that analogy is (in theory at least) a possibility in reality. If you had an infinite amount of matter and then had a infinite amount of anti matter you could have both and still have both infinities albeit they may have to reside in alternate universes, but none the less if multiverse theory ever proves to be correct it would be a possibility in reality.

[saac]

7 hours ago, andrew s said:

 

I think it is more a matter of familiarity or not with particular mathematical concepts that excites and exercises  us.

Reality is what it is and we do our best to tame it with our theories to make the world predictable.

Regards Andrew

Agreed. The trouble I have with infinity Andrew is that it is so beguiling that it takes us to strange places where our imagination runs riot. This can be a good thing of course, challenging our assumptions and understanding. It can give rise to new ideas and understanding of the world. But if we are not careful it can take us down rabbit holes.  Whenever I see infinity in the equation I here a little voice saying "ok so what does this mean in reality".  The equation is telling me something, most likely I have something wrong and normally in my boundary conditions.  

If infinity is real and physically achievable then perhaps the world won't end in a zombie apocalypse after all.  Perhaps CERN will in the near future discover that a non zero rest mass particle can indeed travel at the speed of light (by accident of course) - only at that instance for the universe to disappear from existence as infinity is attained.  

Infinity was best described to me as a process - we can tend toward infinity but never reach it - once reached it is no longer infinity. Mathematicians will however defend infinity to the death, they love it, it intrigues of course it does. Perhaps more so because they have the luxury of not having to cut metal and turn the equation into reality.  I am of course an engineer, as Sheldon Cooper from the Big Bang Theory described, "the younger, slower brother of physics".  I do love that line  - it's my excuse in class.

 

Jim 

 

[Alien 13]

The issue I have with C is why is it so incredibly slow?, you can measure it over small distances (even at home) and I believe high speed cameras have frozen a light beam in action.

Alan

[andrew s]

24 minutes ago, Alien 13 said:

The issue I have with C is why is it so incredibly slow?, you can measure it over small distances (even at home) and I believe high speed cameras have frozen a light beam in action.

Alan

We don't have any real idea why the fundamental constants of nature have the values they do. C seems quite quick to me. 

On the frozen light it is done in a crystal (so not in free space) and is, in a way, like making the refractive index very large. The progress of light is reduced by its interaction with the atoms.

Regards Andrew

[cloudsweeper]

2 minutes ago, andrew s said:

We don't have any real idea why the fundamental constants of nature have the values they do. C seems quite quick to me. 

On the frozen light it is done in a crystal (so not in free space) and is, in a way, like making the refractive index very large. The progress of light is reduced by its interaction with the atoms.

Regards Andrew

And me!  Sheesh - it does 93 million miles from the Sun to the Earth in 500 seconds!

Doug.

[SilverAstro]

The issue I have with C is all those digits, 299 792 458 !  300.10^6 would have made much more sense, just needed a bit filed off the yard measuring stick or whatever that thing is the French use     we have adjusted standards at other times without prob.

I think I have said previously that real (sensible) engineers already do,,, at least they did before calculators became fashionable

coat >>

 

[Alien 13]

10 minutes ago, andrew s said:

We don't have any real idea why the fundamental constants of nature have the values they do. C seems quite quick to me. 

On the frozen light it is done in a crystal (so not in free space) and is, in a way, like making the refractive index very large. The progress of light is reduced by its interaction with the atoms.

Regards Andrew

I think the frozen light was done in a crystal but I am sure I read about laser light traveling through air being slowed enough to see it travel, if my memory is still working some of the tabloid headlines likened it to the discovery of the "light sabre".

Alan

[SilverAstro]

I thought it was in a bose einstein condensate, 1 mph !

[Alien 13]

13 minutes ago, cloudsweeper said:

And me!  Sheesh - it does 93 million miles from the Sun to the Earth in 500 seconds!

Doug.

Working in electronics with fast processing and microwave transmission soon makes you realise how slow electrons (which are still fast relative to C) are even over distances of a mm or so.

Alan

[SilverAstro]

2 minutes ago, Alien 13 said:

and microwave transmission soon makes you realise how

I once had to rig one of those from the battlements of Edinburgh Castle and guess ( through the murk, mist and gloom ) where the other end approx. was at Kirk O'Shots. It is not easy getting line-of-sight up there !

[Paul M]

Infinity is easy.

I once turned up without a booking at a hotel with an infinite number of rooms. "sorry sir, we are full" said the receptionist.

"That's ok! I said, "just ask everyone to move to 1 room number higher than the one they are in, I'll have room 1"

[saac]

Ah Kirk O' Shots my home ground. You're  right about the lack of line of sight, used to drive along the M8 watching the Black Hill transmitters appear above the cloud line!  Come to think of it the cloud line there was often infinite (give or take a few feet)

Jim

[SilverAstro]

5 minutes ago, Paul M said:

I once turned up without a booking at a hotel

and you were astonished to find that my mate Mr Hilbert was the receptionist

3 minutes ago, saac said:

 was often infinite (give or take a few feet)

I can vouch for that

[Thalestris24]

On 2/23/2017 at 17:50, Corkeyno2 said:

Yes, relativity does mean that no massive object can travel at the speed of light. But we're talking hypothetical stuff

Actually, in principle, a particle can travel at the speed of light. What it can't do is accelerate from less than the speed of light up to the speed of light. That's because accelerating it increases it's mass. As it's mass increases it needs more energy to accelerate it up to the point that it needs infinite energy to accelerate infinite mass. However, perhaps if you could neutralise the Higgs field, then maybe otherwise impossible things could become possible and we could nip to the stars in our lunch break!

Louise

[saac]

49 minutes ago, Alien 13 said:

I think the frozen light was done in a crystal but I am sure I read about laser light travelling through air being slowed enough to see it travel, if my memory is still working some of the tabloid headlines likened it to the discovery of the "light sabre".

Alan

I think it was done in a crystal, as Andrew said they are really making the refractive index do the work. I believe the laser pulse was effectively slowed to a walking pace! But again what does it really mean. In a most recent example that I read scientist were able to alternate a crystal from being transparent to opaque with a laser.  They were manipulating the material by changing the way the photons from the laser interacted with the atoms of the crystal. Here is an equally intriguing concept - the femto camera which allows visualisation of short pulses of laser light.  Another example of where I have to say ok so what exactly am I looking at here!

Femto Camera

Jim

[Stub Mandrel]

1 hour ago, Paul M said:

Infinity is easy.

I once turned up without a booking at a hotel with an infinite number of rooms. "sorry sir, we are full" said the receptionist.

"That's ok! I said, "just ask everyone to move to 1 room number higher than the one they are in, I'll have room 1"

"Come back at the end of time when they've finished shuffling up..."

[Thalestris24]

There's a good video about the size of the universe and infinity on youtube. I've watched it loads of times and it's narrated by Dick Rodstein - I just love that guy's voice! There was also an entertaining BBC horizon about infinity. 

Louise

[Tangoringo]

Permission to stick a pencil up my nose and go 'wibble wibble'

That is not meant to trivialise this conversation but to make me realise how limited my imagination is in this respect. Even with 5 espresso's my philosophical thoughts on various physics topics start resembling those of a person who's had far too many pints of Somerset Cider.

[SilverAstro]

12 minutes ago, Tangoringo said:

Permission to stick a pencil up my nose and go 'wibble wibble'

Permission to stick   a pencil    Dark Matter up   my nose    the universe  and go 'wibble wibble'

[SilverAstro]

15 minutes ago, Tangoringo said:

Permission to stick a pencil up my nose and go 'wibble wibble'

Permission to stick   a pencil    Dark Matter up   my nose    the universe  and go 'wibble wibble' 

 

[barkis]

Certainly no shortage of replies on  this Topic. The OP posed 
an intriguing question. Is it true to say the Large Hadron Collider holds the record for high speed collisions,
even though the participants were very small particles?  
That experiment has gone very quiet suddenly.

[andrew s]

38 minutes ago, barkis said:

Is it true to say the Large Hadron Collider holds the record for high speed collisions

Yes, I believe, for man made collisions but not for cosmic ray hits in our atmosphere or for some astrophysical collisions.

Regards Andrew

[saac]

The hunt for the Higgs Boson captured the world's attention but there is an awful lot going on at CERN outside of the LHC.  

CERN Current Projects

As an aside if you find yourself visiting Geneva that take some time to visit CERN, the public exhibition is well worth the effort. Really convenient too, only a short tram ride from the city centre.

Jim

[saac]

On 24/02/2017 at 23:33, Thalestris24 said:

There's a good video about the size of the universe and infinity on youtube. I've watched it loads of times and it's narrated by Dick Rodstein - I just love that guy's voice! There was also an entertaining BBC horizon about infinity. 

Louise

Louise I remember watching that Horizon video some time ago, really enjoyable and just shows how challenging the concept is. The little companion video with  Prof Gowers, for me at least, sums up the dangers of a literal interpretation of infinity. With some very basic algebraic operations Gowers demonstrates how infinity can lead to a nonsensical conclusion that 1 + 1 = 1. 

∞= 1/0    ( a commonly accepted definition) 

0 x ∞ = 1

(0+0) ∞ = 1

0 x ∞  + 0 x ∞ = 1 (line 2) but  0 x ∞ = 1  

therefore  1 + 1 = 1

The outcome is clearly "real world" nonsense; however,  as Gowers explains, one cannot treat infinity as a normal number and expect all the usual laws of arithmetic to hold.  Infinity, aye there be monsters, but also beauty as Blake found:

"To see a World in a grain of sand

And Heaven in a wild flower,

Hold infinity in the palm of your hand,

And eternity in an hour"        

William Blake fragments from "Auguries of Innocence , To See A World" 

 

Jim - still beneath an infinite cloud cover  

[SilverAstro]

8 minutes ago, saac said:

 - still beneath an infinite cloud cover  

Only in 2 dimensions ? Straight up it is quite thin, probably