What Is A Universe?
In the previous blogs, we discussed how the marvels of the cosmos exist hidden in the depths of your mug and also how the scientific method is used to study and understand those marvels through empiricism and rationalism. In this blog, we will answer the question…what is a universe?
Understanding this question is essential to the purpose of our journey. Before we can begin to understand the laws of physics we must first understand what a universe is.
“If you wish to make an apple pie from scratch, you must first invent the universe.”
And in the spirit of Dr. Sagan, you too will learn that:
To brew a cup of coffee, you must first brew a universe.
WELCOME TO THE UNIVERSE
Everything exists in a universe. The word universe is derived from the Latin word Universum (“all matter and all space”) and the Greek word τὸ πᾶν (“the all”). The universe is also synonymous with the Latin word kósmos (“the world”/ “the cosmos”). The universe encompasses everything, and as Carl Sagan so elegantly put it:
“The Cosmos is all that is or was or ever will be. Our feeblest contemplations of the Cosmos stir us…” See: ref 1
SIX COSMIC INGREDIENTS TO THE UNIVERSE
So if a universe contains everything, then… what is everything? What makes up a universe? For any universe, no matter the size or type, you must have the following…
Space
Space is a boundless three-dimensional array in which entities (objects like coffee mugs and humans) and events (a coffee mug smashing into another coffee mug) have a relative position (length, height, and depth). Assigning a magnitude and directions of an object is called its coordinates and are labeled as (x, y, z) on a Cartesian plane (ref 2).
Three-dimensional Cartesian Plane
Time
Time is the continued existence that includes the past, present, and future. The difference between them is the result of cause and effect (see: .causality). If you drop a coffee cup, gravity causes it to fall in a downward trajectory at a constant rate, and a possible effect is that it shatters when it hits the ground. Time depicts slices of three-dimensional space in which change occurs.
Time, space, and causality
Space and time are connected, and scientists refer to this interwovenness as spacetime.
Light
Light is an electromagnetic wave traveling at 3 x 10^(8) meters/second. It is the faster than anything in the universe, and the true universal speed limit. Light also has various wavelengths/frequencies that make up the electromagnetic spectrum: radio waves, microwaves, visible light (that light you see), ultraviolet, x-rays, and gamma rays.
Electromagnetic spectrum
Matter
A universe contains matter–physical substances that contain mass. All mass is made up of atoms and particles. Coffee can come in several different phases:
1. Solid
2. Liquid
3. Gas
Although these phases appear different, they all have one thing in common: atoms (ref 3 ). The phases of matter differ only by how these atoms are arranged. In a solid, atoms are arranged in ordered lattices through strong chemical bonds and small bond distances (ref 4). Liquids and gasses, on the other hand, can take on the form of their environment because they have a greater distance between bonds and lower density of atoms. Instead of creating an ordered lattice, liquids usually have a highly disordered arrangement of atoms; in a gas, atoms move freely.
Matter Is Organized
Atoms are the fundamental building blocks of all complex objects in the universe. They are organized as follows:
Atoms are the building blocks of molecules…
…molecules are building blocks of DNA…
…DNA are the building blocks of cells…
…cells are building blocks to prokaryotes and eukaryotes…
…eukaryotes are the building blocks of organic life, like you and me.
Atoms are also the building blocks to inorganic life like metals, cosmic clouds of dust and gas, where through gravity, these can condense to create stars, planets, asteroids, meteoroids, moons, and etc.
Dark Matter
Although matter seems to be ubiquitous in our daily lives, it is actually a very small portion to what a universe contains. In fact, the ratio in our universe is (ref 5):
4% Matter
Atoms, particles, stars, galaxies, dust, you, me, and coffee…
Of that 4%, Hydrogen makes up 73%, Helium composed 25%, and 2% other elements (ref 6)
22% Dark Matter
74% Dark Energy
We will discuss dark matter and dark energy in the next blog. For now, we shall leave them in the dark.
Forces
So what is a force?
A force is any push or a pull that changes the initial state of an object by changing an object’s momentum as a function of time (ref 7). Forces extend through spacetime, but their strengths depend on the proximity to their source (whether it be mass or charge).
What is a field?
A field is both a mathematical and physical quantity used to express a force’s extension in spacetime. Fields have a magnitude at each point in space and time (ref 8); and a field with a stronger magnitude corresponds to a point in space that has a greater force. A field, like the gravitational or electric field, is spatially infinite, meaning it propagates throughout all space.
The Four Fundamental Forces of Nature
In Star Wars, a single force permeates all space, such that a Jedi can tap into it and use it to control objects and minds of their enemies. In our universe, we have four fundamental forces that permeate all spacetime and scientist use these to develop new technology, understanding of the cosmos, and enhance the minds of their students.
Gravitational Force
Mass attracts mass. The greater the mass, the larger the attraction. The gravitational field is an attractive field that describes the magnitude of the force that brings all masses together. It responsible for all cosmic, planetary, and galactic evolution. It literally keeps you on the ground and the ground on the earth and the earth orbiting the sun and the sun orbiting the Milky Way and so forth. So what is gravity? According to general relativity, gravity is in fact just the curvature of space and time (ref 9). All objects with mass curve spacetime and the curvature of spacetime tell objects how to move. This was Einstein’s genius insight into the universe (ref 10). In fact, that coffee mug sitting before is bending spacetime right now, it’s just that its curvature is too small to feel!
Gravitational Force
Electromagnetic Force
The electromagnetic force is responsible for the movement and behavior of charges. Any charged particle has an electric field propagating throughout all space. There are two types of charges: positive and negative. Like charges repel and opposite charges attract. A moving electric field in time creates a magnetic field and a changing magnetic field in space creates an electric field. For more information in EM force, see: ref 11
So how strong is the electromagnetic force to the gravitational force?
If you compared the two forces, you’d find that the electromagnetic force is 10^(37) times stronger than the gravitational force (ref 12). In fact, this is the reason why, when you jump off a table and hit the ground, you don’t go falling all the way to the center of the earth (your electrons and the electrons of the ground’s repulsive force overcomes the gravitational force)!
Strong Force
The strong force is responsible for keeping the atomic nucleus together. It is literally the glue that keeps that quark inside the protons and neutrons from decaying (which is why they call it a gluon) (ref 13). And although it works on a very small length scales, it is by the far the strongest force; in fact, it is 137 x stronger than the electromagnetic force.
Strong nuclear force interaction.
Courtesy of By Manishearth — Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=12868220
Weak Force
The weak force or interaction is responsible for radioactive decay (ref 14). When unstable atoms decay, they release “radiation”, which can sometimes be harmful. A few forms of radioactive decay include alpha decay (excited helium nucleus), beta decay (fast electrons), gamma radiation and x-rays.
For more information on fundamental forces, see: Forces of nature
How forces, fields, and subatomic particles coexist
All forces are described by fields. All atoms are formed of subatomic particles. For example, the nucleus is composed of protons and neutrons, which are made of smaller particles called quarks. Here’s where it gets interesting. All force fields exchange certain subatomic particles called “force carriers or Gauge Bosons” (ref 15). An exchange of these particles creates a force. All the particles in the universe are summarized in the standard model of particle physics (ref 16). Each of these particles is organized by their charge, mass, and spin. The ones responsible for the four forces of nature are:
1. The exchange of gluons is responsible for the strong force
2. The exchange of photons is responsible for the electromagnetic force
3. The exchange of Z and W bosons are responsible for the weak force
4. The exchange of gravitons is responsible for the gravitational force.
ENERGY
Energy is the true currency of the universe. It can never be created nor destroyed, only transformed from one type to another. A few types of energy include:
Kinetic — Energy created from a moving object. The equation Kinetic Energy is KE = 1/2mv², where v is the velocity of an object.
Potential — Energy possessed by a body due to its position relative to a field,
Heat — created by the vibration and motion of molecules
… and more (see: ref 17).
One important unification of particles, fields, forces, and matter is that of mass and energy. In the special theory of relativity, Einstein came upon his most infamous equation (ref 18), E = mc² were:
E = energy
m = mass
C = the speed of light
This equation is the rest energy/mass of an object, which tells us one thing: mass and energy are equivalent in nature.
A RECIPE FOR A UNIVERSE
- MIX YOUR MATTER
Mix together all the matter, dark matter, energy, and fundamental forces into spacetime. - SET YOUR PORTION SIZE
Next, we need to define the portion size. In physics, we call the portion size the “physical constants of the universe”, which are constants that are invariant i.e. they do not change (ref 19). These constants set the particle masses, force strengths, and speed of light. - COMPRESS TO A SINGULARITY
The next step is to compress into a point of zero volume and infinite density. We call this a spacetime singularity. A singularity is an infinite curvature of space, where gravity is so strong that not even light itself can escape from. (You may know this as a “black hole.”) - ADD SOME HEAT
Add heat. Creating a universe requires a tremendous amount of heat. We are talking about 10^(27) — 10^(33) Kelvin (ref 20). Remember, a typical oven reaches around 450 Farenheight which is ~505 K. So to heat a universe, you will need a billion billion billion million of those standard home ovens. - WAIT FOR A QUANTUM FLUCTUATION
At this temperature, all the fundamental forces are unified. From this point on, it’s all quantum gravity. And as those forces coalescence and the fields of quantum theory begin to rumble… a ballet occurs between particles and anti-particles. Here, energy fluctuates wildly and unpredictably like a cosmic bull.
Waiting….just a little longer…and then….
…to be continued…
