# Is being a sunbeam all its cracked up to be?

Thread Starter

Join Date: Jun 2009

Location: Bedford, UK

Age: 67

Posts: 1,273

**Is being a sunbeam all its cracked up to be?**

In the course of a pointless and fruitless discussion at work, to which I am a frequent contributor, the subject of the speed of light came up. Since I know many here have a deep interest in this, no one will be too surprised at the turn of conversation. Based on half remembered theory, I pointed out in answer to some desultry chat that at relativistic speeds the school boy formula for relative velocity doesn't work and you have to use the special relativity result such that two photons heading for each other would determine their relative speed to be c and not 2c.

When the applause died down I then ventured into more troublesome territory in which I imagine life as a photon which has caused me to think and I am not sure I have a proper grasp on this.

At the speed of light, all dimensions are contracted to zero so my little photon eyes can't see the universe, everything is a point. If it's a point then there's nowhere to travel to so speed is meaningless. Given time dilation an observer would see my watch had stopped ticking so I would spend an eternity going nowhere. If the universe is a point, all photons, energy and so on is concentrated at that point so it's effectively the big bang singularity.

Am I doomed to spend eternity at the instance of creation going nowhere, and if that is every photons reality, how can other realities be co-existing?

Will think of this next time a light is shone in my face.

Thought I would share ( it's raining outside.....I think. Perhaps I need to get out more).

When the applause died down I then ventured into more troublesome territory in which I imagine life as a photon which has caused me to think and I am not sure I have a proper grasp on this.

At the speed of light, all dimensions are contracted to zero so my little photon eyes can't see the universe, everything is a point. If it's a point then there's nowhere to travel to so speed is meaningless. Given time dilation an observer would see my watch had stopped ticking so I would spend an eternity going nowhere. If the universe is a point, all photons, energy and so on is concentrated at that point so it's effectively the big bang singularity.

Am I doomed to spend eternity at the instance of creation going nowhere, and if that is every photons reality, how can other realities be co-existing?

Will think of this next time a light is shone in my face.

Thought I would share ( it's raining outside.....I think. Perhaps I need to get out more).

Join Date: Feb 2001

Location: The Winchester

Posts: 5,937

Am I doomed to spend eternity at the instance of creation going nowhere

Join Date: Sep 2002

Location: Great South East, tired and retired

Posts: 3,223

And of course, the poor photon gets horribly confused when he is accepted as being an electromagnetic wave instead of a particle. Instead of LGBTFSQ3 problems he has PEW troubles.

Thread Starter

Join Date: Jun 2009

Location: Bedford, UK

Age: 67

Posts: 1,273

@Tone. Time has stopped for the photon but not me. No idea how you read a clock that's sizzling past like that but the time information from the photon must travel at speed c too, but relative to the photon the equation gives a relative speed of 0/0. I suspect that if you conjure up a theory which is based on a finite limit for relative speed which applies to the whole universe, like what Einstein did, then anything which travels at that speed is a bit special and fundamentally fundamental.

Odd to imagine a thing which just sits static in its own spaceless position for eternity when others are outside and get on with life. Must be worse than an old fashioned wet Sunday in 1950's Britain.

Odd to imagine a thing which just sits static in its own spaceless position for eternity when others are outside and get on with life. Must be worse than an old fashioned wet Sunday in 1950's Britain.

**Cunning Artificer**

Join Date: Jun 2001

Location: The spiritual home of DeHavilland

Age: 73

Posts: 3,124

One ponders on the possibility that there may only be one photon and it is everywhere at once. Space, time and life as we know it is a pure illusion that encapsulates all possibilities.

...or is it?

...or is it?

Thread Starter

Join Date: Jun 2009

Location: Bedford, UK

Age: 67

Posts: 1,273

Well as the universe is just a point, and photons are dimensionaless, which they must be for the zero size universe, suppose you can pack as many in there as you want, being bosons. Can't remember all that mode counting business but a point can't have axes so no modes. Hmm, photon must have finite size which must be the size of the universe so not exactly a point, or maybe a point with some uncertainty.

**Ecce Homo! Loquitur...**

Join Date: Jul 2000

Location: Peripatetic

Posts: 10,990

Blacksheep,

Feynman posited, more as a thought experiment than anything else, that there was only one electron bouncing backwards in time. When he and others then worked out what that would look like using quantum field theory - the result was identical to the positron.

Not it a feasible theory for the photon which is destroyed when it converted to electrical or chemical energy in a solar array or nature - or when 2 photons collide and produce two positron-electron pairs.

Feynman posited, more as a thought experiment than anything else, that there was only one electron bouncing backwards in time. When he and others then worked out what that would look like using quantum field theory - the result was identical to the positron.

Not it a feasible theory for the photon which is destroyed when it converted to electrical or chemical energy in a solar array or nature - or when 2 photons collide and produce two positron-electron pairs.

Join Date: Apr 2008

Location: Oz

Posts: 279

This subject has always intrigued me. I find the theories just a tad confusing as would a vast percentage of humanity. What I wonder about is how much of it is completely wrong. The maths quite often confirms the theories, but this doesn’t mean it is correct. String theory, M theory, multiverse, dark matter, varying amounts of extra dimensions, cats in boxes etc. We can make the math fit but how long did humans think the earth was at the centre of the universe (or flat and chemtrail covered) This would have been scientific fact for how many years and how many people would have been stoned or burnt at the stake for considering otherwise.

Everyone knows the answer is 42.

Everyone knows the answer is 42.