John0117

As you may realise I dont know how many photons it takes to make something visible so I am trying to keep things simple by using density per sq cm which can then be multiplied up by someone who knows how much light is required to make something visible. Doing some rough calculations taking the suns radius as approx 2.5 light seconds and 1 sq cm equaling 1 sq cm at that point taking photon density as 1.5 billion per squ cm. if area increases at the rate of r2 then at 1 light year the radius has increased by a factor of 12,600,000 if we square that and apply it to our original sq cm it has increased to approx 1.5 bil sq cm or a density of 1 photon per sq cm. So at 10 light years we get a density of 1 photon per 100 sqcm and this is not far in universal terms and I initially thought it would only show up over intergalactic distances. Of course if we look at volume we would start with 1 cubic cm (this would give us a starting point of around 1.8 billion billion (sqrt 1.5 cubed) or somewhat more than 100 million billion mentioned) which would still give us a density of 1.8 bil bil photons divided by 1.5 bil cc at 1 light year and at 10 light years that number divided by 100 per cc. I am only increasing sideways assuming depth remains the same. I am of course willing to accept my maths may be incorrect. At what point or density would something cease to become visible.

Some good information. The quagga actually fits in with a thought I had this morning and that is Light looks like a wave from the side and a photon end on. Imagine the difference between an arrow approaching you sideways and end on. The shaft producing the interference pattern and the head producing the dots (from post 7) The shaft representing the energy carried and the head the momentum. Would that possibly be a reasonably accurate picture?

Yes thanks for the animation it shows what I mean exactly. If the dots represent photons and they are touching when in the middle then as they spread out there are gaps where there are no photons and so no light. Post 6 A billion photons per square centimeter does not sound a lot to me but if that represents part of the surface area of a star like the sun, or a sphere with the radius of the sun then increase that radius to the maximum distance that the sun would be observable at then what area would that square cm represent and what density the photons (there would have to be the same number that we started off with) Remember we can see these objects from wherever we are along the earths orbit so there have to be enough photons available at all points along that orbit to make the source visible. I assume the diameter of the instrument being used to do the observing would also have to be taken into account or not ?

I am trying to picture a photon. E=hv and wave length is relatively easy. A wave being wavey and energy linked to its length. Obviously a wave means an EM type wave with electric and magnetic fields oscillating at right angles. So how would a photon appear, as a square perhaps for want of a better word. In the dual slit experiment a single photon is used how would that differ from a single wave as it still produces an interference pattern as a wave would. Sorry to be a pain but I am just trying to get it right. Better to ask silly questions than get the wrong idea.

Rather than sidetrack my other post I will ask the question here. I have been unable to find any useful description of the word photon other than discrete bundle or wave-packet neither of which are very helpful. The descriptions available seem to describe a particle like structure rather than a wave like structure. So how are photons and waves connected, what relationship does the energy of a photon have with wavelength. If light travels as photons why bother to describe it moving as Electro-magnetic waves.

It is not the number of photons per second I am concerned about it is how they spread out across space. That is imagine photons per second like a line of photons one behind the other, it is how the photon at the front spreads out sideways to that line.the ones behind will naturally follow. Or put another way how does a wave-front of single photons side by side spread out sideways as they are moving forwards. The surface area of something as big as a star is still finite and so presumably only a finite number of photons will sit side by side over that area, these are the end points of the radiating straight lines in post 1. You are I suspect thinking of frequency which in this case is not applicable unless the back ones are moving faster than the front ones in order to fill the gaps.

Recently while posting a theory about how the universe works on another site, I came across a problem when dealing with waves and gravity. The basis of the problem goes back to one of the ancient greeks and his thoughts on infinity. If you take a curved surface, in this case a star, and draw as many straight lines as possible radiating out from its surface then no matter how many lines you draw if you draw a larger circle around the original there will be gaps between the lines, the greater the radius of the second circle the bigger the gaps. Light travels, basically, in straight lines. EM waves oscillate, 2 waves at right angles, simulations are easy to find on the internet. If looked at end on they would, looking at the simulations, appear as a cross. Increasing amplitude apparently increases brightness, the only way for a cross shape to spread out is to increase in amplitude or lengthen the arms. The question then is when looking at distant objects, in terms of millions of light years (the radius of the second circle above), how does light spread out to fill the gaps between the lines without increasing in amplitude. Brightness apparently drops off according to inverse square over distance thus reducing amplitude. In other words if light travels in a straight line then we are infinitly more likely to see a gap than to see a light wave. Also if it spreads out as a circle there would be overlaps and gaps thus making the distant object seem to brighten and disappear over time. There would of course be no problem if the 2 distant objects were flat surfaces opposite each other, although this would cause a similar problem if looked at from any angle. Hope the above makes sense. I do have a possible solution but would like to hear from experts before making any final conclusions or causing any arguments.