The Universe Revealed is my attempt to discuss more thoroughly the main questions that we humans should ask about our existence, our universe and our place in it. These are mostly my thoughts on science, religion and philosophy as it applies to the human condition. My first book, The Theory of Nothing, covered many subjects. This book will be more specific to the big questions about life and what it means.

All rights reserved - Copyright © 2015 - The facts are as true as I can make them, but the opinions and conclusions are mine. No disparity or offense is intended to anyone or anything, including any religion or belief system.

What is the universe?

I'm starting out this series with a definition of the term 'universe'.

The literal definition of the universe is that it's everything that exists, has existed, and will exist. As far as we know, the universe is made up of both matter and energy. Fortunately for us, the amount of matter in the universe is just enough to have prevented the universe from collapsing back onto a singularity or expanding so fast that it could not form stars and galaxies.

The universe is thought to consist of 4.6% atoms, 23% dark matter and 72% dark energy. We know about atoms and what they are composed of, but we do not currently understand what dark matter or energy is. Thus, we only understand 4.6% of the universe. The other part is unknown.

Originally, 13.7 billion years ago, the universe consisted of 12% atoms, 15% photons, 10% neutrinos, and 63% dark matter.

Matter in the universe today consists of atoms, ions, and electrons, which form stars, planets, nebulae and other cosmic objects. Matter can exist in the form of solid, liquid, gas and plasma. There are also theoretical forms. Besides that, elemental or quantum particles can exist in space, and that includes things like photons, neutrinos, antimatter and quarks.

First of all, we have no idea how extensive the universe is. The reason for this is the fact that both time and space expanded after the Big Bang. We believe that the universe is 13.7 billion years old because of the cosmic background radiation temperature data, but we don't know how large the universe is because of the fact that the universe expanded faster than light for a short period right after the Big Bang, and it's still expanding at an accelerated rate.

Because of direct observation, mostly with the Hubble telescope, we can currently say that the observable universe is 91 billion light years in diameter. If we take half of that, we have a radius of 45.5 billion light years. That's much larger than 13.7. I'm using the logic here that if a specific packet of energy formed at the Big Bang and then it formed atoms that ended as a galaxy, we would see it 13.7 billion years later if nothing expanded. With expansion, we would see it much later, which is the case. The reason why we don't know the true size of the universe is that the expansion is near the speed of light at the furthest extent of what we can see. The light that comes from things beyond that point can't get back here. The bottom line is that we have no idea how large the universe really is.

Current thinking is that the universe is infinite with a finite time. That's based on observations of the cosmic background radiation left over from the Big Bang and several other observations using the latest spacecraft probes. However, this conclusion is only theoretical because we can't see beyond the edge of the universe that is still observable. The galaxies at this observable edge will eventually vanish because of the expansion.

The observable universe is estimated to contain 100 billion galaxies and 300 sextillion stars; although, there could be many more than this. Stars are contained in galaxies, galaxies are clumped into galaxy clusters and galaxy clusters are clumped into galaxy superclusters. If one could observe the universe from outside it would appear to be like a tangled sponge structure. The universe is both homogeneous and isotopic, meaning that it looks the same from any direction and there is no center. That sounds to me like an infinite universe.

Astronomers study the structure of the universe. They try to understand what stars are made of and why they are collected into structures that are called galaxies, and why galaxies are collected into clusters. They also try to understand the structure of planets, moons, comets, asteroids, and energy phenomena like pulsars, quasars, and gamma ray bursts. These are the things that can be seen because they emit or reflect light across the electromagnetic energy spectrum, which includes visible, ultraviolet and infrared as well as radio frequencies. To do this they use reflector telescopes, radio telescopes and a host of space probes that can detect electromagnetic energy across the full spectrum. Astronomers are also interested in how stars form, exist on the main sequence, and ultimately die. They study the remnants of star deaths, including nebulae, white dwarfs, neutron stars, pulsars, magnetrons and the ultimate astronomical objects, black holes.

Cosmologists are interested in how the universe formed and what its final fate is. They rely on observations made by astronomers, but they also use quantum physics. Some consider cosmology to be a branch of metaphysics, which is a branch of philosophy. Cosmologists deal with the extremely large.

Quantum physicists deal with the ultimate structure of the universe and how it actually works. Most of their work is theoretical using math. They study things like quarks, bosons and leptons. They deal with the extremely small.

Amazingly, science now studies the universe from both ends, both the very small and the very large. We know more than we ever did, but we've only scratched the surface. In my next essays I want to discuss the big questions about the universe that we humans ask.

Thanks for reading.