Surmises Concerning Light

Why does space appear dark though it is dominated with the light emitted by the countless billions of stars existing in it? The space between the Earth and the Moon is a good example: we don't see nor detect the Sun’s light, which travels through this area, except this light is reflected on the Moon’s surface. Similarly, the space beyond the Moon, also dominated with the Sun's light, appears dark, and the light traveling through it remains undetected until it is reflected on the surface of a planet, a comet, or any another object may travel through this area of the space. In the same way, during a total solar eclipse the onlooker sees the outermost atmosphere of the Sun, the corona, glowing, but beyond the corona, in every other direction, the space is also dark, although the Sun’s light is undoubtedly traveling through it.

We cannot attribute this paradox to what is known as the destructive interference of waves, where the coincidence between the peaks and troughs of light's waves makes the waves cancel each other, creating darkness– discovered by Thomas Young (1773 – 1829) through his double-slit experiment whereby he proved that light traveled in waves. Were the destructive interference the reason of the darkness of space, patterns of the destructive interference would have appeared as dark strips on the various phases of the Moon. But this doesn't happen. So, an explanation to this paradoxical phenomenon should be sought through the following three hypotheses:

The first hypothesis is that light is invisible to us when it is traveling in space in parallel direction as to the onlooker's position. The second hypothesis is that light cannot be visible while traveling through a virtual vacuum. These two hypotheses may be supported by the notion that if the light traveling through space were visible to us in any case, no part on the surface of our planet would have experienced what we call "night", since the Sun's light dominates all the space around the Earth. Earth's images taken from the surface of the Moon also support this notion.

The third hypothesis is that light is not a "visible form" of the electromagnetic radiation, but light is a "visible effect" happens when the electromagnetic radiation travels through a medium or contacts with a surface. That is to say, though the human eye is able to see various sources of the electromagnetic radiation, all the forms of radiation emitted by these sources are invisible to us; but we can see the effect that takes place– illuminating– when these radiations travel through a medium or become reflected on the surfaces of objects. This resulting effect is what people are accustomed to call it "light".

To prove, or even to refute, the later hypothesis we may ask ourselves two questions: in any lit place, do we see light itself or we see its effect in the medium it travels through – the gases of Earth's atmosphere – and its reflection on the surfaces of the objects found about us? What appears to us as bundles of light starting out from a source of light, be it natural or artificial, is it really the way in which light is emitted by that source, or it is the Earth's atmosphere that is responsible for creating these light-bundles?

Photos taken by astronauts on the surface of the Moon give an answer to the first question. In these photos – taken during the Moon's two-weeks-long daytime – we see the astronauts and their lunar vehicle against a dark background of space whilst the Sun "lights" the ground on which they are standing. Were the Moon have an atmosphere through which the Sun's radiation traveled, the astronauts would have appeared against a bright background. This indicates that during daytime on the Earth we don't see a visible radiation reaches us from the Sun, but we see the effect of this radiation in the atmosphere and its reflection on the surface of objects found about.

As to the second question, I think that Earth's atmosphere is responsible for turning the radiations traveling through it into what appear to us as "light-bundles". All the images taken for the Sun at the different bands of the electromagnetic spectrum show the Sun beamless. The view of the beamless Sun we see at sunset attribute to each factor its act: the Sun emits radiation; the atmosphere "bundles" it. It is not totally a deceiving effect of the atmosphere, however. It is this bundling that guarantees that when we point out our radio telescopes to a certain target located in deep space that we receive its particular radio waves, "squeezed" from among all the other radio waves traveling through the width and breadth of our Universe. (Does this notion of the "squeezed radio wave" suggest that each "light-bundle" contains a complete range of electromagnetic radiation?)

To conclude, what we are accustomed to call it 'light' is not a visible form of the electromagnetic radiation, but it is the electromagnetic radiation itself in its only "picture" that can directly be detected by the human eye, on terms that this radiation travels through a medium or be reflected on the surface of an object. (Is this conclusion supported somehow by the equation of James Clerk Maxwell (1831 – 1879) whereby he proved mathematically that all the electromagnetic waves traveled at the speed of light?)