“Paradox created by misinterpreting cosmological redshift as Doppleresque waveform decompression.”
The ‘Accepted’ Explanation
When we look at very distant objects in space, the light that we see is always to some degree more “red” than it should be. That is to say, the wavelength of the light is longer than expected for the type of galaxy or quasar being observed.
A similar phenomenon occurs when a car drives by with its horn blaring.
As the car approaches us, the sound waves created by the horn are compressed due to the motion of the car coming toward us; i.e. the wavelengths of the sound waves are shorter and the frequency of the sound increases. But, as the car passes by, the waves decompress and the frequency of the sound drops to a lower pitch. The faster the car is traveling, the greater the effect.
The same principle is used in various Doppler Radar devices (though using microwaves instead of sound waves); to measure the radial velocity of storm systems; to find planets orbiting other stars; or to catch you exceeding the highway speed limit.
In space, when a star within our own galaxy (the Milky Way) is moving away from us, the wavelength of its light also decompresses, causing blue light to appear more green (moving toward the redder end of the spectrum). Yellow light becomes more orange. Red light drops into the infrared range.
Within our galaxy, there are examples of both blueshift (object approaching) and redshift (object receding), depending upon the motion of the observed stars relative to our own position. But, when viewing objects outside our galaxy, light waves are predominantly shifted from blue to red. This would seem to indicate that virtually every other galaxy in the universe is moving away from us. These observations ultimately gave rise to the notion of the expanding universe, an idea which then became responsible for initiating the concept of the Big Bang.
By measuring how “redshifted” the light from a distant galaxy is, a determination can be made about the speed at which the observed galaxy is receding from us. Edwin Hubble proposed that the distance to a faraway object is proportional to the speed at which it is receding from our position. In other words, the further away the observed object, the faster it’s moving away from us.
This created some problems initially, since some galaxies (based on “Hubble’s Law”) appeared to be flying away from us at velocities greater than the speed of light; i.e. faster than the universal “speed limit” will permit [strictly enforced]. That misperception was remedied by invoking a relativistic requirement for very distant objects; i.e. when matter is moving at a very rapid rate, the passage of time (for that object) moves relatively more slowly. Though this resolved the problem of galaxies appearing to travel even more quickly than light, it still leaves us with the unlikely conclusion that a few galaxies (very far away from us) seem to be moving at something close to 90% of the speed of light.
So, “dark energy” was theoretically proposed to be the driving force behind the incredibly-rapid, but logically-deducible, expansion of the universe.
An Alternative (Heretical) View
The simplest solution often being the best, let’s look at cosmological redshift in a completely different way.
In classical mechanics, when an object moves at a given velocity between one point and another, that object has momentum, which is the product of its speed and its mass. Since light has no mass, it is commonly believed that light must have no true momentum. However, if we accept that light does have a special kind of momentum, which we can call effective momentum, then we can see its waveforms in a whole new “light”.
When blue light (having a short wavelength) passes through our atmosphere, it scatters more than red light (with its longer wavelength) does. The blue light can be said to be more materially interactive. Similarly, when discussing light refraction, as through the medium of a prism, blue light bends more than red light. The shorter the wavelength of the light, the greater the refraction. In response to a source of strong gravity, shorter wavelength (bluer) light reacts more like a material particle, its trajectory being altered by the gravity source more than its longer wavelength (redder) cohorts; though, to the observer, the light will become bluer or redder depending upon whether the observer is standing closer to–or further away from–the gravity source.
If bluer light displays more mass-like properties (is more materially interactive), then it can also be considered to have a higher effective momentum even though it has no true mass.
If we take the next step and view cosmological redshift (the reddening of light over the vast intergalactic distances) as the result of light’s declining effective momentum, then we would not be required to accept that some galaxies are zipping away from us at speeds perilously close to that of light.
Though the speed of light remains constant, the energy density at the observed wavefront declines according to the inverse square law. Energy being equatable with mass, this leads to a degradation of light’s effective momentum along with a corresponding transformation of the waveform to a lower frequency / longer wavelength.
Light is supremely efficient. It always finds the shortest route in its journey between two points – which is often not a straight line, owing to the way that gravitational influences curve space and flex time. At the primary origin (source) of light’s emanation, its waveforms are a model of efficiency, being integrally dependent upon the energy output of the process that creates them. High energy reactions emit short (high density) waveforms; e.g. gamma rays or x-rays. Low energy reactions emit longer (lower density) waveforms; e.g. microwaves or radio waves.
As light travels over extreme distances, its energy density declines and its effective momentum falls, which leads to a naturally contingent change in the waveform’s signature. (Think Planckian locus.) And, because light never completely loses its momentum (unless it stops being light), wavelengths will gradually grow (and redden) until they eventually fall below perceptible limits.
Of course, taken to its logical end, this means that there actually was no “Big Bang” and that the universe is not expanding — though it may very well be oscillating.
But maybe we should leave that discussion for another time…