Where expansion of space is relevant and where not:

Better way to say that the Universe is expanding only within intergalactic space, that too beyond the zero gravity spheres around the galaxies relevant, but such intergalactic space may not mean the gravitationally bound cluster or super cluster of galaxies - where there is considerable influence of gravity. 

Our Galaxy, Milky Way, is gravitationally bound with Andromeda galaxy, these galaxies belong to Virgo Cluster. Therefore, the space between these galaxies, since gravitationally bound, may not follow the same nature in expansion as in other intergalactic space - not gravitationally bound.

 

#expnasionofspace #expansion

 

The Universe and the nature of its expansions:

Our Universe began forming in its location of the origin at the Big Bang event 13.8 billion years ago; - space began, expanded through inflation, accordingly time needed to begin its uniformed succession in the primordial existence of said event. The universe grew from an almost infinitely small point to nearly an octillion times in size called Cosmic inflation - a faster than light expansion of the universe that spawned the primordial existence, following this universe continued to expand at a slower rate. The acceleration of this expansion began after the universe was already over 7.7 to 9.8 billion years old, called metric expansion of the space. The current rate of expansion of the universal space is between 66 and 74 km/s/Mpc (kilometers per second per mega-parsec.)

1.   Therefore, there is no centre of the current universe; as it was left at the location of its origin.

2.   Gravity does not have influence within the intergalactic space, at least, in intergalactic scale, specifically ruled by some mysterious influence.

3.   The distant galaxies observed to be surrounded by zero-gravity spheres within specific intergalactic space.

4.   The accelerated expansion of the intergalactic space recede the distant galaxies due to said mysterious influence.

5.   The galaxies at the edge of the visible universe observed to be receding faster than the light speed. Those galaxies are entering into invisible universe, so that light cannot reach us from such distance.

6.   The space, within the gravitationally bound cluster or super cluster of galaxies, does not expand.

7.   Some non-luminous non-interacting material appears to make up most of the mass of galaxies and galaxy clusters. 

 

#TheUniverse #Universe #MetricExpansion #Expansion #Inflation #VisibleUniverse #BigBang

Fundamental interactions - Interaction between Gravity and Electromagnetism: (1-6)

1.    Fundamental interactions are irreducible forces those act between the elementary particles composing all matter. There are four fundamental forces in the universe - the strong force, the weak force, the electromagnetic force, and the gravitational force. They work over different ranges and have different strengths. The strong nuclear force is the strongest and gravity is the weakest of the four fundamental forces of nature, but gravity has a far reaching range.  

2.     The elementary particles are fundamental particle or subatomic particle those are not composed of other particles. The three basic types of known elementary particles are leptons, quarks and gauge bosons. The leptons type subatomic particle are electron, muon, or neutrino, they do not take part in the strong interaction. A quark is a fast-moving point of energy. The quarks make up an atom's nucleus, viz. protons and neutrons, each proton and neutron contains three quarks respectively. There are six types of quarks up, down, charm, strange, top, and bottom.

3.    The gauge bosons are carrier particles for three of the four fundamental forces. A gauge boson is a bosonic elementary particle that acts as the force carrier for elementary fermions. Elementary particles, whose interactions are described by a gauge theory, interact with each other by the exchange of gauge bosons, usually as virtual particles. There are four kinds of gauge bosons. W and Z bosons, which carry the weak force. Gluons, which carry the strong force. Photons, which carry the electromagnetic force.

4.    A photon is an example of a boson as it has a spin of 1 and carries electromagnetism. A photon is an elementary particle representing a quantum of light or other electromagnetic radiation viz. radio waves, known as the quantum of the electromagnetic food. A photon carries the electromagnetic energy proportional to the radiation frequency but has zero rest mass.

5.     Gravity and electromagnetism are two of the four fundamental forces, out of the four fundamental forces. There are many similarities between electromagnetic (EM) radiation and gravitational radiation - both travel at the speed of light; both carry energy away from their sources; both consist of transverse waves with two polarizations. The main difference between gravity and electromagnetism is that gravity is a force between masses whereas electromagnetism is a force between charges.

6.    A photon (electromagnetic radiation) interacts with gravitational radiation and carry away energy from their respective sources.

#FundamentalInteractions #ElementaryParticles #Gravity #Electromagnetism #Photon

Bending of travelling path of a photon or spacecraft.

Summary: A photon exchanges momentum as it bypasses a large gravitational well during transit. The photon experiences a change in momentum and its path is bent as it interacts with the gravitational field. A photon simultaneously gains and loses momentum (p) from a gravitational interaction with a massive object. However, a photon maintains its relative path with speed c and covers the same distance (d) as compared to its constant speed. The curvature of the photon's path is understood in terms of the exchange of momentum experienced by the photon.

Relevant equations: p = E/c, constant = c = 299792458 m/s, distance = (speed x time) = (c m/s * s)

Bending of the travelling path of a body when its speed is unchanged: - photon, spacecraft:

The bending of photon's path is due to it's constant speed @c but it's increased energy and frequency corresponding to the increased gravitational influence on it. 

Since photons speed is constant, an incremental change in it's energy and/or frequency makes the photon change it's path bent. 

It's like gravity assist (sling shot) by a massive planetary body to a bypassing spacecraft in a condition when the speed of the spacecraft remains unchanged but its path bends as its kinetic energy increases.

What happens in the background:

When the photon maintains a constant speed @c, and increases its Energy, it is bound to increase its frequency too. Such increased frequency, at its constant speed, does not allow the photon to maintain a straight path anymore, as the gained frequency deviates the photon path from its apparent straight path to a bent path until the the photon reaches its earlier frequency.

The gain of its energy is temporary - temporarily synchronised. Photon frequency synchronised with gravitational field - transfers energy to the photon.

The Planck's Equation: E=hf ----> E'=hf'  when E'>E (Temporary).
So (E'-E) deviates the path of the photon and bends, since the photon cannot increase it's constant speed, it bends.

Note: The momentum of a photon is directly proportional to its frequency and inversely proportional to its wavelength. Photons momentum is given by p=hλ, where λ is the photon wavelength. Photon energy and momentum are related by p=Ec , where E=hf=hcλ for a photon

#gravityassist #slingshot #increadedenergy #increasedfrequency

The Universe (13.8 billion years) - unobservable (23 trillion ly.) and observable (46.5 billion ly.)

Beyond the visible universe, the invisible or the unobservable universe must be at least 23 trillion light years in diameter, and contain a volume of space that's over 15 million times as large as the volume we can observe. So that no signal can travel faster than light, hence there is a maximum distance beyond which nothing can be detected, as the signals could not have reached us yet. 

The visible universe is observable universe and it's physical limit created by the speed of light itself. This means a sphere with a radius of 13.7 billion light years centered around the Earth, and we can only observe 13.7 billion light years of the universe. Because the electromagnetic radiation from these objects has had time to reach the Solar System and Earth since the beginning of the cosmological expansion. The visible universe contains 4.9% ordinary matter (baryonic), 26.8% Dark matter and 68.3% Dark energy. Only five percent (5%) of the universe is visible and its radius is 46.5 billion light years.