First of all, you should know that Hubble’s Law Of Cosmic Expansion is the most celebrated Paper in the history of physical science. Yup, even more than the physics of black holes.
In fact, if Hubble’s expanding universe theory has not been discovered then we might have been still living in the dilemma that whether our universe is static or expanding or even our universe is shrinking.
What Is Hubble’s Law Of Cosmic Expansion?
Hubble’s expansion law states that “Objects Observed In Extra-Galactic Space (Deep Space) Are Shifting Away Or Receding Away From Earth.
In other words, According to Hubble’s law of cosmic expansion, all the galaxies are moving away from our own. A phenomenon in today’s world is known as Cosmic Recession.
Not to mention, Hubble’s law solidified the physics of the expanding universe. Meaning, we are living in the ever-expanding universe.
This expanding universe theory is also known as Cosmological Red-Shift; only and only if the galaxy is receding away from planet earth.
In fact, you can also say that the cosmological redshift was the phenomenon observed by Edwin Hubble which was used to explain the expansion of the universe
On the other hand, if the galaxy is approaching the earth, it’s called Cosmological Blue-Shift. Take a note here. Cosmological redshift is used to measure the physics of the expanding universe. Therefore, it is not truly a Doppler effect.
Historical Facts About Hubble’s Law
If you don’t know, it was Albert Einstein’s General Theory Of Relativity’s Papers from which the notion of the ever-expanding universe arrived.
As a matter of fact, almost a decade before Edwin Hubble’s declaration of Hubble’s Expansion Equations; in 1922, a Soviet Russian Mathematician and Physicist Alexander Friedmann had derived Friedmann’s Equations from Einstein’s Field Equation.
Alexander Friedmann showed that the universe might be expanding, directly contradicting the Classical View of the Universe that we are living in a Static Universe or Newtonian Universe.
Moreover, five years after Alexander Friedmann’s Friedmann’s Equations and two years before Edwin Hubble’s Hubble’s Law; a Belgian Astronomer Georges Lemaître proposed The Expanding Universe Theory.
In fact, he also proposed a hypothesis of the Primeval Atom or the Cosmic Egg. A hypothesis, which in today’s world is famously known as the big bang theory of the universe.
Mathematical Representation Of Hubble’s Expansion Equation
The mathematical representation of Hubble’s Law Of Cosmic Expansion is stated as:
V = H × d
V = Galaxy’s recessional velocity
H = Hubble Constant or Hubble Parameter
d = Galaxy’s distance from the one which it’s being compared
Hubble Constant is constant only in space but changes over time; therefore, the currently accepted value is 70 kilometers/second per megaparsec
Hubble’s Law And Einstein’s Blunder
While developing his General Theory Of Relativity; Einstein assumed the universe to be static and dynamically stable. Meaning, the universe is neither expanding nor contracting.
In fact, he was actually using the same assumption Sir Issac Newton did for his newton’s law of universal gravitation. An assumption that we know as a Static Universe (Steady-State Theory).
But, when the experimental observations of General Relativity were compared with the theoretical prediction; both the results (experimental and theoretical) were different.
In other words, Einstein theoretically assumed the universe to be a static one. On the contrary, the experimental observation showed that the universe is rather expanding or it will contract (observations like bending of light by large masses or the precession of the orbit of mercury).
Therefore, in order to counteract the observational results, Albert Einstein had to modify his General Theory Of Relativity by introducing the Cosmological Constant.
A constant that is used to produce a static solution to counter the effect of gravity, simply to produce a perfectly Static and Flat Universe.
However, after the discovery of Hubble’s Law Of Cosmic Expansion, Einstein had to abandon his work on Cosmological Constant.
Albert Einstein himself called his assumption of the Cosmological Constant; the biggest blunder.
Well, what do you think? Was the hypothesis of cosmological really the biggest blunder? Or, maybe we just don’t know how to effectively utilize it….!!! I mean, there was a time when people believed in the Aristotelian universe.
But, in today’s world, it comes in the list of one of the obsolete cosmological models of the universe. What I want to say is there is always a possibility for new laws in the world of physical science. What do you think? Is Hubble’s law of cosmic expansion is really untouchable?