From Einstein's cosmological constant to dark energy:

In 1917 Einstein applied his theory of general relativity in the universe, and suggested a model of a homogeneous, static, spatially curved universe.

In 1917, Albert Einstein inserted a term called the cosmological constant into his theory of general relativity to force the equations to predict a stationary universe in keeping with physicists' thinking at the time.

Alexander Friedmann was a Russian mathematician and meteorologist who lived a short but eventful life. During the revolution of 1917 whilst besieged by White Russian forces in Petrograd (now St. Petersburg) he heard about Einstein's work on general relativity. He started to derive solutions, publishing his findings in 1922. His key insight was to realise that there was no unique solution to Einstein's equations, rather there was a whole family of solutions possible. This family of solutions thus allowed for different cosmological models of the Universe.

In Friedmann's models the only force that is considered is gravitation. His model universes are homogeneous (the same everywhere on a large enough scale) and isotropic (look the same in every direction). Most importantly they incorporate the concept of expansion and in some cases, contraction. Einstein himself had viewed the Universe as static. Friedmann thus provided the theoretical framework for an expanding Universe within the spacetime and mathematics of general relativity. Unfortunately he contracted typhoid and died in 1925 during the Russian civil war before his work became widely known.

In 1922 Friedmann introduced the idea of an expanding universe that contained moving matter. Correspondence with Einstein suggests that Einstein was unwilling to accept the idea of an evolving Universe and worked instead to modify his equations to ensure a static eternal Universe as believed from Newton's time.

Some years later, in 1926 Hubble published the redshift vs. distance relationship, namely, all the galaxies in the neighbourhood seemed to be receding at a rate proportional to their distance, formalising an observation made earlier by Carl Wilhelm Wirtz. It may be noted that in 1927 Belgian astronomer Georges Lemaître also independently reached the conclusion of an evolving Universe

Until 1931, physicist Albert Einstein believed that the universe was static.  Albert Einstein accepted the modern cosmological view that the universe is expanding long after many of his contemporaries. An urban legend attributes this change of perspective to when American astronomer Edwin Hubble showed Einstein his observations of redshift in the light emitted by far away nebulae -- today known as galaxies. But the reality is more complex. The change in Einstein’s viewpoint, in fact, resulted from a tortuous thought process. Now researchers explain how Einstein changed his mind following many encounters with some of the most influential astrophysicists of his generation.

However, the universe was not static. It was expanding. This observation, and those preceding Hubble's paper, led Belgian priest Georges Lemaître to propose in 1931 that the universe originated from a small and compact state, what he called a "Cosmic Egg" and what is now called the Big Bang.

When it became clear that the universe wasn't actually static, but was expanding instead, Einstein abandoned the constant, calling it the '"biggest blunder" of his life.

In 1932 Albert Einstein teamed up with the Dutch theoretical physicist and astronomer, Willem de Sitter, to propose an eternally expanding universe which became the cosmological model generally accepted until the middle of the 1990s. To Einstein's relief these two models no longer needed the cosmological constant.

The majority of the energy in our Universe went completely undiscovered until the late 1990s, and scientists still don't know what it is. Only 5% of the Universe, in terms of energy, is made out of things we're familiar with and understand: protons, neutrons, electrons, photons, neutrinos, black holes and even gravitational waves. Of the remainder, 27% is dark matter and 68%, the largest amount, is in the form of a new, mysterious substance called dark energy.

Dark energy was first revealed observationally by examining the light from ultra-distant signals like supernovae. With measurements of both distance and redshift, scientists concluded that the Universe couldn't just be made of matter and radiation, but needed a new form of energy that would change the fate of our Universe. Here's why, more than 20 years later, it's still the biggest unsolved problem of them all.

The effective mass of dark energy is <0 and its gravitating mass is more than matter mass that results a strong effect at large scale as such, the cosmological expansion accelerate.

Antigravity exerted by dark energy affects a cosmic structure strongly at large scale. The dark energy background produces antigravity which is stronger than the matter gravity in the present Universe as a whole. This makes the cosmological expansion accelerated.

The cosmic antigravity can be stronger than gravity globally and also locally in the scale between 3.26 lightyear and 3.262×10⁷ lightyear. The local weakfield dynamical effects of dark energy adequately described in term of Newtonian mechanics, and its effective gravitating density is negative, producing antigravity.

Gravity dominates at distances, while antigravity is stronger than gravity, therefore, a gravitationally bound system with its mass can exist only inside the zero gravity sphere of its radius [circumference of a sphere where, (antigravity - gravity = 0)], while dark energy is effective in the outer region of the domination of gravitating mass and practically have no effect within the strong domination of gravitating mass.

===================Alexander Friedmann ====================

The father of the Big Bang....

Alexander Friedmann corrected Einstein and found solutions to the field equations describing expanding, contracting and oscillating universes. He was a pure mathematician with interests in application of mathematics in the physical sciences and he originated the theory of the expanding universe.

The idea of a static universe goes back to Newton's absolute space and time, but even Newton was worried about the stability of the cosmos: The entire universe would collapse according to the universal attractions of all pieces of matter. When Einstein applied his improved theory of gravity to the whole universe, he could not find a distribution of the mass which would give a stable universe. Later he introduced a cosmological term, representing a repulsive force, which would save the universe from collapse. He proved that the universe must necessarily be stable and unchanging in time. When Friedmann wrote to Einstein that he had made an error in his proof which opened a new class of expanding, collapsing and pulsating world models and there was no need of changing Einstein's original gravity equations, Einstein did not respond. Many years later when Gamow discussed cosmology with Einstein he remarked that, the cosmological term was the biggest blunder he ever made in his life".

Source: Aug 09, 1997, Michael Cramer Andersen, Lecturer in Physics and Astronomy

Friedmann is seen as a profound, independent-minded, and daring thinker who destroys scientific prejudices, myths and dogmas; his intellect sees what others do not see, and will not see what others believe to be obvious but for which there are no grounds in reality. He rejects the centuries-old tradition which chose, prior to any experience, to consider the Universe eternal and eternally immutable. He accomplishes a genuine revolution in science. As Copernicus made the Earth go round the Sun, so Friedmann made the Universe expand.

In 1922 Alexander Friedmann published his famous paper on cosmology where he discovered non-stationary solution of Einstein's equations, describing closed expanding space with beginning and end of the Universe in time-closed Friedmann model.
In 1924 he published a paper on expanding Universe with negative curvature, infinite in space but having beginning in time. At that time he also published a popular book "The world as space and time" where discussed a new vision of the expanding Universe with possible beginning and end in time.

#CosmologicalConstant #DarkEnergy #AntiGravity #AlbertEinstein #AlexanderFriedmann

 

Dimensional reach, in view of space and time:

None can affect anything in higher dimensions from a lower one. However, a higher dimensional entity can affect lower dimensional entities. 

• A point has no dimension but has a conceptual location, imperceptible to us.  
• Length added to a point is one dimensional (line), and perceptible to us.
  
• Height added to a Length is two dimensional (plane), and perceptible to us.  
• Depth added to a plane is three dimensional (space), also perceptible to us.  
• Another dimension added to space is four dimensional, imperceptible to us. 

It is clear from the above statements that a lower dimensional entity won't have complete reach in its immediate higher dimension. However, a higher dimensional entity contains all of its lower dimension/s and can affect or influence anything in lower dimension/s. 

As for example, we (being three dimensional) can sense (view and hear) a video from a two dimensional screen but anything from us is not sensible to the entities within the two dimensional screen. 

Since, space is three dimensional and time is conceptual fourth dimensional, as such space can't affect or interact with time. And they are incompatible to make an alliance. 

#spacetime #space #time #dimensions #dimensional

The Big Bang nucleosynthesis: The first 20 minutes, timeline & chronology of the Universe.

The Big Bang nucleosynthesis:

One may get a fair idea on how the Universe came into being from nothing from the Big Bang nucleosynthesis of the Universe. The nuclear reactions in a process called Big Bang nucleosynthesis. Nucleosynthesis is the formation of new atomic nuclei, the centres of atoms that are made up of protons and neutrons. The first nuclei were formed a few minutes after the Big Bang, a quark-gluon plasma, a soup of particles known as quarks and gluons, condensed into protons and neutrons, further process formed new atomic nuclei from pre-existing nucleons i.e. protons and neutrons, and nuclei.

Similarity:

Evidence of nucleosynthesis in other stars has been discovered in S-Type stars by Merrill (1952). Nucleosynthesis in main sequence stars involves fusion of 4 Hydrogen nuclei into Helium (He4 or α-particle) through a chain of reactions called the Proton-Proton chain (as first discovered by Hans Bethe in 1939). Stellar nucleosynthesis is the nuclear process by which new nuclei are produced. It occurs in stars during stellar evolution. It is responsible for the galactic abundances of elements from carbon to iron. The synthesis of the naturally occurring elements and their isotopes present in the Solar System solids may be divided into three broad segments: primordial nucleosynthesis (H, He), energetic particle (cosmic ray) interactions (Li, Be, B), and stellar nucleosynthesis (C and heavier elements).

The timeline of the early universe:

The timeline of the early universe outlines the formation and subsequent evolution of the Universe from the Big Bang (13.799 ± 0.021 billion years ago) to the present day. An epoch is a moment in time from which nature or situations change to such a degree that it marks the beginning of a new era or age.

The chronology of the universe:

The chronology of the universe describes the history and future of the universe according to Big Bang cosmology. The earliest stages of the universe's existence are estimated as taking place 13.8 billion years ago, with an uncertainty of around 21 million years at the 68% confidence level.

 

The first 20 minutes:

• Planck epoch - the Planck epoch or Planck era is the earliest stage of the Big Bang, before the time passed was equal to the Planck time, tP, or approximately 10^−43 seconds. It is generally assumed that quantum effects of gravity dominate physical interactions at this time scale.

• Grand unification epoch - The Grand Unification Epoch took place from 10^-43 seconds to 10^-36 seconds after our universe was born. During this period, three of the four fundamental interactions—electromagnetism, the strong interaction, and the weak interaction—were unified as the electronuclear force. Gravity had separated from the electronuclear force at the end of the Planck era. The strong force separated from the other fundamental forces.

• Electroweak epoch - The quark epoch ended when the universe was about 10^−6 seconds old. The electroweak interaction is a fundamental force representing unification of the electromagnetic and weak nuclear interactions. The work of three physicists, Glashow, Weinberg, and Salam, showed that the electromagnetic and weak nuclear forces can be understood as a single interaction.

• Quark epoch - The quark epoch ended when the universe was about 10^−6 seconds old, when the average energy of particle interactions had fallen below the binding energy of hadrons. During the quark epoch the universe was filled with dense, hot quark–gluon plasma, containing quarks, leptons and their antiparticles.

• Hadron epoch - The Hadron epoch started 20 microseconds after the Big Bang and lasted from 10^-6 seconds until one second. The universe was now around 1 trillion degrees which allowed quarks to combine and form hadrons. Hadrons are subatomic particles made up of quarks, anti-quarks, and gluons. There are two categories of known hadrons: baryons and mesons. Most of the hadrons and anti-hadrons were eliminated in annihilation reactions, leaving a small residue of hadrons. Upon elimination of anti-hadrons, the Universe was dominated by photons, neutrinos and electron-positron pairs.

• Lepton epoch - The Lepton epoch commencing about 10^−5 s after the Big Bang, in which the various kinds of lepton were the main contributors to the density of the Universe.

• Photon epoch - The photon epoch was the period in the evolution of the early universe in which photons dominated the energy of the universe.

Matter era:

The period in the evolution of the universe, beginning roughly 105 years after the big bang, when the universe had cooled to the point at which electrons and protons were able to form neutral hydrogen atoms, and continuing to the present time, during which matter, in the form of atoms, is dominant over radiation.

• Cosmic Dark Age - The cosmic dark ages were a time when the universe was enveloped by a fog of neutral hydrogen that trapped the light of the first stars and galaxies. The fog didn't lift until 1 billion years after the Big Bang, when the neutral hydrogen had been re-ionized and once again split apart.

• Galaxy epoch - From 370,000 years until about 1 billion years. After recombination and decoupling, the universe was transparent but the clouds of hydrogen only collapsed very slowly to form stars and galaxies, so there were no new sources of light,  large galaxies were formed through a rapid gravitational collapse that would have resulted in huge bursts of star formation at early epochs, leaving behind galaxies that had rapidly exhausted their fuel to age quiescently until the present; these galaxies appear now as large collections of old, red stars, such as elliptical galaxies and the central bulges of spiral galaxies.

• Acceleration - Dark-energy dominated era begins, following the matter-dominated era during which cosmic expansion was slowing down.  Messier 67 open star cluster forms. Three exoplanets confirmed orbiting stars in the cluster including a twin of our Sun. Lalande 21185, red dwarf in Ursa Major, forms. Proxima Centauri forms completing the Alpha Centauri trinary system.

Epochs of the formation of the solar system:

9.2318 billion years, Sun forms - Planetary nebula begins accretion of planets. 9.257 billion years, Solar System of Eight planets, four terrestrial Mercury, Venus, Earth, Mars evolve around the sun.

 

#TheBigBang #Nucleosynthesis #TimelineOfTheUniverse #ChronologyOfTheUniverse #PlanckEpoch #GrandUnificationEpoch #ElectroweakEpoch #QuarkEpoch #HadronEpoch #LeptonEpoch #PhotonEpoch #MatteEra #CosmicDarkAge #GalaxyEpoch #UniversalAcceleration #EpochsOfTheSolarSystem

 

Universal Singularity, is it nothing to us?

Nothing is absence of something. And something as we know can only exist within our three dimensional real world.

So anything that exists extra-dimensional  - location originating outside the known physical reality of the Universe - cannot be a part of our three dimensional real world so that we can never establish such existence though the known laws of physics applicable to our real world.

Moreover, such extra-dimensional existence; without events - space and time (we know) would cease to exist - and such universal singularity would be a meaningless proposition to us, where all known fundamental interactions - weak and strong interactions, electromagnetism - were united into one – gravity.

Therefore, such imperceptible something is beyond our real senses, rather nothing to us. No known laws of physics can establish them as real something, except in mathematical concept. 

Read more here

#universalsingularity

If an object has momentum without mass is only possible if this is a wave:

Einstein's general equation derived from the relativistic definitions of the energy and momentum of a particle:

• E²=p²c²+m²c⁴.

Where E is the total energy of the particle, p is the momentum of the particle, c is the speed of light, and m is the mass of the particle.

When a particle is at rest i.e. p=0 then this equation reduces down to:

• E=mc²; (p=0)

But When a particle with no mass i.e. m=0, the equation reduces to:

• E=pc; (m=0)

Since photons have no mass and therefore get all of their energy from their momentum, so they must follow: E=pc; If an object has momentum without mass is only possible if this is a wave. A wave transports momentum via its waving motion and not by physically transporting an object with mass.

Moreover, if a particle has no mass and is at rest then its total energy is zero:

• E=0; (m=0) & (p = 0)

Conclusion a particle with no mass and is at rest is nothing at all since it has no energy.

Therefore, if an object with no mass is to physically exist, it can never be at rest but must always travel at the universal speed limit c; such is the case with light. Light consisting of photons and photons don't have rest mass but momentum and energy. Momentum is the directional property of an object in motion that describes its ability to influence another object upon impact.

In addition to that, if the object travels less than the universal speed limit c, say, at some speed v then we can always choose a reference frame travelling along with the object so that the object will be at rest in this reference frame.