An original theory or New Hypothesis regarding the Expansion of the Universe.

The universe is expanding at the velocity of light.
The universe is not expanding as a result of the Big Bang.
Gravity does not affect Universe Expansion.
There is only the observable universe.
An original theory and new hypothesis of the universe.

The universe is closed, positively curved, and asymptotically flat. [1]

"Space and time have a real existence independent of the matter and energy that exist within them." (Jim Al-Khalili)
This means that mass (and gravity) do not affect the overall Space and Time. This is an after-the-fact explanation.

What are stars made of?
It was astronomer Cecilia Payne who found the answer. In her 1925 doctoral dissertation, she showed that stars are primarily composed of hydrogen and helium. This illustrates how important it is to understand the properties of the hydrogen atom. [2]

Who discovered the radial velocities of galaxies?
In 1912, astronomer Vesto Slipher performed the first measurements of the radial velocity of the Andromeda Galaxy, and to observe the shift of spectral lines of many galaxies discovering their galactic redshifts. [3]

Who discovered the pulsation-period-luminosity distance relationship for galaxies?
It was the work of astronomer Henrietta Leavitt to find the distance using her discovery of the period‑luminosity relationship, where the absolute magnitude of Cepheid variables varied with their brightness/dim period. By knowing the luminosity of a source it is possible to measure the distance to that source by measuring how bright it appears to us: the dimmer it appears, the farther away it is. [4]

Who discovered the distance to galaxies?
Giving the distance to Cepheid stars by comparing its known luminosity to its observed brightness, calibrated by directly observing the parallax distance to the closest Cepheids. It has now been one hundred years since astronomer Edwin Hubble found the distance to the Andromeda nebula in 1924. [5]

Who discovered the velocity-distance relationship with respect to galaxies ?
Using Slipher's work on redshifts Hubble found a consistent velocity‑ distance relationship in other distant objects. In 1929, Hubble published his velocity‑distance diagram. Later, Hubble himself publicly recognized the extremely important role of Slipher, and he later wrote to Slipher of the importance of "Your velocities and my distances". [6]

What is the Cosmological Principle?
On the largest scales, the universe is homogeneous and isotropic. When physicist Arno Penzias and radio‑astronomer Robert Wilson discovered the Cosmic Microwave Background in 1964, this was the first modern confirmation of this principle, which states that the universe is the same everywhere. The Cosmic Microwave Background (CMB) snapshot shows a near‑uniform distribution. If each part of the cosmos has always been expanding uniformly at the velocity of light, then they have very similar conditions across the universe. [7]

Is the universe radiation background totally uniform? ?
Theoretical physicist Werner Heisenberg's proposal of uncertainty, a principle that is basic to quantum theory, comes into play. The uncertainty principle asserts that it is physically impossible to measure the exact position as well as the exact momentum of a particle at the same time. The more precisely one quantity is measured, the less precisely the other is known. This quantum fluctuation manifests as small discrepancies and not an absolutely uniform CMB. [8]

Can far‑flung galaxies affect us gravitationally?
They already have. From the Big Bang onward, for each nucleon, the curvature of space‑time tells matter how to move and has expanded outward at the velocity of light, in the form of gravitational waves known as the cosmic gravitational wave background. All matter is connected, then and now. [9]

Does each volume of space have the same temperature ?
At the scale of the universe, the concept of thermodynamic equilibrium says so. Now, like gravity and light, and again from the Big Bang onward, all of space‑time is connected, as heat‑carrying light expands with the universe. The universe expands at the velocity of light. [10]

Soon after the Big Bang, we have recombination, which marks the beginning of the Cosmic Dark Ages where light absorption was maximal, with mostly HI atoms prevailing. Photons can be absorbed by the electron cloud around each atom rendering HI clouds opaque. At redshift z≈1089, or about 13  million years, re‑ionization began, eliminating a major photon absorption line. This was done by removing the electron cloud around hydrogen atoms and began the widespread emergence of ionized hydrogen. These early stars helped ionize hydrogen atoms H⁺, which allowed for universe‑wide transparency. [11]

Gravitation pulled matter together which led to the early formation of stars and then galaxies. [12]

NASA's Wilkinson Microwave Anisotropy Probe (WMAP) announced in 2003 that the first stars were formed at redshift z≈20, or about 690 million years old. At about one billion years the Cosmic fog had lifted at redshift z=13.5, as the universe gradually transitioned into our visible sky. Now with denser, hotter, more intense star formation, the universe was richer in smaller spiral and irregular galaxies as opposed to the giant elliptical galaxies we see today. [13]

Is there a definitive redshift-distance relationship?
Yes. Now, consider that we have a linearly expanding universe, where an object with a specific redshift implies a perimeter(circumference) distance to that object, using the following arguments.
We consider the perimeter(circumference) P of a circle that represents our universe at age U_Age. We come up with two equations describing the expansion of the universe. [14]

Massive stars (at least with a mass over eight times that of our sun), create neutron stars, and as such massive stars are often created in pairs, which are likely to create neutron stars in pairs enhancing the likelihood of neutron‑star mergers.

Are the ad hoc expansion forces of cosmic inflation and dark energy related in some way?
Yes, neither exists nor has ever existed.

What were the contributions of physicist Albert Einstein and mathematician Alexander Friedmann ?
It was the General Relativity equations, which has correctly explained the contents of the universe. And yet, General Relativity still needs a separate theory of inflation to explain the evenness of the universe. It cannot solely be used to account for an expanding universe. [15]

Now Special Relativity alone can be used to account for such an expansion. The velocity of light c is profoundly tied to the Fine Structure Constant α and as such is a true constant. My calculations have shown that the value of α can be described by the following formula, which is an exact real number.

How long have neutrinos been around?
Presumably for 14.57 billion years. My Special Relativity calculations have shown that time dilation can be described by the following equation. [16]

If neutrinos travel no less than v/c=0.9999999999995, then this implies
t'/t=sin cos^-1(0.9999999999995) = 0.000000999999999999875 or a million to one, implying the oldest neutrinos have only experienced 14,570 years! Note: this means neutrinos travelling from our sun to earth experience 1/2000 seconds and not 500 seconds.

While early stars have not been observed, some galaxies have been observed from about 736 million years cosmic time z=18.7 and were identified in 2023 by the James Webb Space Telescope (JWST).
Note: In millions of years, cosmic time is determined by the ratio 14570/(z+1). As well, we have had spectroscopic confirmation of these metal‑poor galaxies e.g. z=2.5(4.142 billion years), z=3.9(2.959 billion years), z=8(1.611 billion years), z=10.38(1.274 billion years), z=10.6(1.25 billion years), z=11.3(1.178 billion years), z=11.58(1.152 billion years), z=12.63(1.063 billion years) and z=13.2(1.021 billion years). [17]

The universe will continue to appear very similar for many billions of years into the future. Our Solar System formed about 4.6 billion years ago with the earliest traces of life on Earth emerging about 3.7 billion years ago.

At some time the Stelliferous Era (the age of stars) will end where matter is organized into stars, planets, nebulae, galaxies and galactic clusters. This era is thought to run from about 10⁶ to 10³⁹ years, as stars are no longer being born, and the expansion of the universe will mean that the easiest galaxies to see are our local galaxies. There are various scenarios for the far future and the ultimate fate of our universe. Don't worry, in the future, there will be no Big Rip, no Big Crunch, and no Big Bounce.
The Hubble-Slipher constant can be computed directly assuming that the Universe expands at exactly the velocity of light.
It as thought that the Type Ia category of supernova produced a fairly consistent peak luminosity because of the fixed critical mass at which a white dwarf will explode.
We now have something called the double-detonation supernovae of sub-Chandrasekhar mass white dwarfs that no longer needs such a thing as a fixed critical mass. [18]

The universe is now an age of 14.57 billion years where its perimeter(circumference) is P_m = 4467 megaparsecs.
Note that HD 140283 is estimated to be 14.46±0.8 billion years old.
In four dimensions the volume(surface) is given by 2π²r³ where Perimeter(circumference) = 2πr, giving the volume to be V = P³/4 π.
The universe contains 10⁸⁰ protons, so the Universe completely filled with protons occurs three hours after the big bang, and the Universe completely filled with hydrogen atoms occurs three years after the big bang
The volume of the universe is now seven cubic gigaparsecs, which equates to 2.05454×10⁷⁷ cubic metres. Given a universe energy density of 411 photons/cc, it follows that there are 8.44416×10⁸⁵ CMB photons in the whole universe. ^∗

In the long term (after many trillions of years of cosmic time), the age of stars will end. Beyond this, all objects in the universe will cool and decompose progressively back to their fundamental particles, by a variety of possible processes.

What is the velocity of light? What is the velocity of gravity?
They have the same value, the expansion rate of the Universe.

The universe is finite and ever‑expanding. It is not cyclic. The whole universe is observable.

^∗ All calculation errors are my own.