Breaking Down ‘Dark Energy’!

A source of light waves moving to the right.
frequency is higher on the right, and lower on the left.

Heard of the Doppler shift ?
Sure have, when the cars zooms past us sound undergoes a Doppler shift . Now imagine the car speeds away from us. Hence the successive wave like crests of sound that are emitted from the source car arrive later, further take more time to reach you (fixed observer),because the car constantly speeds away. Time taken for the sound crests to reach you increases, frequency decreases, the wave gets ‘REDSHIFTED’. Why Red ?. Red light has lower frequency than violet within the visible E.M spectrum hence the name. Observe this happens because the sound travels in a medium ‘air’ here. Therefore velocity of the observer and of the source are RELATIVE TO THE MEDIUM in which the waves are transmitted.

This simple phenomenon of ‘REDHIFT’ was also surprisingly universally observed for light during the 1910’s by Vesto Slipher for spiral galaxies and soon after for all galaxies. Implications weren’t clearly understood then. Ten years later Alexander Friedmann derived equations from general relativity showing that the universe might be expanding(or contracting cause of the dynamic nature of the spacetime) in contrast to the Static Universe model. Then keeping in light with the discoveries, Edwin Hubble empirically proved these observations of redshift from galaxies rushing away in all possible directions. Important to keep in mind is that it does not contradict Special Relativity or General relativity as for light waves or gravitational waves, the shift in wavelength necessarily compensates for the shift in frequency keeping the speeds of the waves constant ‘C’. Another essential fact is that there is no medium. When light is in observation the calculation WON’T INCLUDE THE MEDIUM of propagation as a reference point.   

The implications were extremely clear consequently, the known universe is indeed expanding. Every other galaxy is not just moving away but ACCELERATING away from our galaxy . Acceleration implies a force. The value of this repulsive acceleration is 1.2 x 10^-8cm/sec^2 . This force being the REPULSIVE kind. Force corresponds to energy over a period of time. According to the relativity theory, energy is equivalent to mass as a source of gravity. Which then according to general relativity means producing a positive curvature in space-time. So it curves the universe over the scale of ‘R’ equal to 10^27  cm^2  or 10 billion light years. Termed ‘DARK ENEGRY’ because of its undefined origins and little known dimensions of working and no known force carriers.  A very fascinating value, whose significance may well lie beyond our current understanding. This could possibly be assumed to be the famous cosmological constant that was hypothesized through the equations in General Relativity by Einstein. He proposed changes in G.R to accommodate its value, so that the repulsive force from the cosmological constant would balance out with the gravitational attraction to give a STATIC(never changing) model of the universe. That was the held belief for the past millennium, very hard to get out of, even Einstein’s insightful mind. 

Dark Energy's Significance in the Evolution of the Universe
(click to expand view)

Fascinating features worth mentioning involve, its density which appear exactly the same to all observers, with no preferred position, velocity, time, direction of motion extending uniformly throughout the universe. For positive values it causes the universe to expand, for negative causes it to contract and for a zero value causes it to remain static.

Energy as we know it now, is associated with matter. Dark Matter suggests exceedingly more. Its value is constant irrespective of any variance in the measurement circumstances. It has no known force carrying ‘BOSONS’ or massive ‘FERMIONS’. Majorly it comprises of 73% of the energy density of the universe still we’re unaware of its true nature. This should blow anyone away and it does accomplish that every time.
A few other facts that kick start some intuitive questions I’ve noticed are given here.
The cosmological constant now assumed to be dark energy extends over the scale of the entire universe of ‘R’. Perform a few related calculations at this scale, using universal constants to surprisingly get uncommon constants.
‘C’ the speed of light, perform R/C and you get time, which is roughly the present age of the universe.
Inverse this value and you get a frequency, probably the lowest possible achievable oscillation. Once per lifetime of the universe.
Next up perform C^2/R, gives acceleration, the value turns out to be the familiar value of the repulsive acceleration we know of, mentioned earlier
1.2 x 10^-8cm/sec^2. All of this gained simply out of operations using the speed of light. So many revelations from this data are yet waiting to be discovered.

One of the most exciting prospects that arise from experimental and theoretical observations, is the relation between the two very distinct phenomena ‘Dark Matter’ and ‘Dark Energy’. The features they hold in common might reveal completely new physics in the ‘R’ scales. This could trigger a re-formulation of many of the existing ground breaking laws in Physics. Even String Physics to that extent does not predict the existence of either Dark Matter or Dark Energy, while this does not mean String theory is wrong. You can always tweak it in ways that does accommodate ‘Dark Stuff’. This may also convey we’ve just seen the tip of the iceberg.
As we often see every few centuries. Precision of the experiments increase, we find anomalies that do not comply with existing data and suggest theories to overcome those anomalies which also predict further phenomena , if confirmed classify into established theories. Unraveling the usually overlooked and enlightening relationship between Dark Energy and Dark Matter would be done in the following posts.