We live in a wonderfully complex universe, and we are curious about it by nature. How many of us have wondered;
Where did we and the world come from?
What is the world made of?
What are we made of?
Can we change the universe, at least our universe?
It is our privilege to live in a time when enormous progress has been made towards finding some of the answers. String theory and quantum mechanics are the most recent attempt to answer some of these questions.
In the mid-16th century, Copernicus argued that the Earth is not the center of the Universe.
Several decades later, Galileo’s telescope showed him stars beyond measure: a glimpse of the vastness of the cosmos.
At the end of the 16th century, the Italian philosopher Giordano Bruno speculated that the Universe might be infinite, populated by an infinite number of inhabited worlds.
The idea of a Universe containing many solar systems became commonplace in the 18th Century.
By the early 20th Century, the Irish physicist Edmund Fournier d’Albe was even suggesting that there might be an infinite regression of “nested” universes at different scales, ever larger and ever smaller.
And now we are troubled by the question if our Universe is one of many…
The idea of parallel universes once consigned to science fiction, is now becoming respectable among scientists – at least, among physicists. Physicists have proposed several candidate forms of “multiverse”, each made possible by a different aspect of the laws of physics.
The trouble is, virtually by definition we probably cannot ever visit these other universes to confirm that they exist. So the question is, can we devise other ways to test for the existence of entire universes that we cannot see or touch..
So, what is our world made of?
Ordinary matter is made of atoms, which are in turn made of just three basic components: electrons whirling around a nucleus composed of neutrons and protons. The electron is a truly fundamental particle (it is one of a family of particles known as leptons), but neutrons and protons are made of smaller particles, known as quarks. Quarks are, as far as we know, truly elementary.
There are four fundamental forces in the universe: gravity, electromagnetism, and the weak and strong nuclear forces. Each of these is produced by fundamental particles that act as carriers of the force.
The behavior of all of these particles and forces is described with impeccable precision by the Standard Model, with one notable exception: gravity. For technical reasons, the gravitational force, the most familiar in our every day lives, has proven very difficult to describe microscopically. This has been for many years one of the most important problems in theoretical physics– to formulate a quantum theory of gravity.
Quantum physicists discovered that physical atoms are made up of vortices of energy that are constantly spinning and vibrating, each one radiating its own unique energy signature. Therefore, if we really want to observe ourselves and find out what we are, we are really beings of energy and vibration, radiating our own unique energy signature -this is fact and is what quantum physics has shown us time and time again. We are much more than what we perceive ourselves to be, and it’s time we begin to see ourselves in that light. If you observed the composition of an atom with a microscope you would see a small, invisible tornado-like vortex, with a number of infinitely small energy vortices called quarks and photons. These are what make up the structure of the atom. As you focused in closer and closer on the structure of the atom, you would see nothing, you would observe a physical void. The atom has no physical structure, we have no physical structure, physical things really don’t have any physical structure! Atoms are made out of invisible energy, not tangible matter.
“If quantum mechanics hasn’t profoundly shocked you, you haven’t understood it yet. Everything we call real is made of things that cannot be regarded as real.” ( Niels Bohr, Danish physicist who made foundational contributions to understanding atomic structure and quantum theory)
Quantum mechanics treats particles as if they are waves, and describes them with a mathematical expression called a wave function. Perhaps the strangest feature of a wave function is that it allows a quantum particle to exist in several states at once. This is called a superposition.
But superpositions are generally destroyed as soon as we measure the object in any way. An observation “forces” the object to “choose” one particular state.
The conclusion that was drawn was that the very act of observation caused the wave function to collapse and create the existence of matter. Independent of observation particles exist in a state of a wave function, which is a series of potentialities rather than actual, object. The result inferred was that matter didn’t exist independent of observation or measurement.
This switch from a superposition to a single state, caused by measurement, is called “collapse of the wave function”. The trouble is, it is not really described by quantum mechanics, so no one knows how or why it happens.
In his 1957 doctoral thesis, the American physicist Hugh Everett suggested that we might stop fretting about the awkward nature of wave function collapse, and just do away with it.
Everett suggested that objects do not switch from multiple states to a single state when they are measured or observed. Instead, all the possibilities encoded in the wave function are equally real. When we make a measurement we only see one of those realities, but the others also exist.
This is known as the “many worlds interpretation” of quantum mechanics.
Everett was not very specific about where these other states actually exist. But in the 1970s, the physicist Bryce DeWitt argued that each alternative outcome must exist in a parallel reality: another world.
Suppose you conduct an experiment in which you measure the path of an electron. In this world, it goes one way, but in another world, it goes another way.
That requires a parallel apparatus for the electron to pass through. It also requires a parallel you to measure it. In fact, you have to build an entire parallel universe around that one electron, identical in all respects except where the electron went.
In short, to avoid wave function collapse, you must make another universe.
In DeWitt’s view, any interaction between two quantum entities, say a photon of light bouncing off an atom, can produce alternative outcomes and therefore parallel universes.
As DeWitt put it, “every quantum transition taking place on every star, in every galaxy, in every remote corner of the Universe is splitting our local world on earth into myriads of copies.”
Not everyone sees Everett’s many-worlds interpretation this way. Some say it is largely a mathematical convenience, and that we cannot say anything meaningful about the contents of those alternative universes.
But others take seriously the idea that there are countless other “yous”, created every time a quantum measurement is made. The quantum multiverse must be in some sense real, they say because quantum theory demands it and quantum theory works.
You either buy that argument or you do not. But if you accept it, you must also accept something rather unsettling.
The other kinds of parallel universes, such as those created by eternal inflation, are truly “other worlds”. They exist somewhere else in space and time, or in other dimensions. They might contain exact copies of you, but those copies are separate, like a body double living on another continent. In contrast, the other universes of the many-worlds interpretation do not exist in other dimensions or other regions of space. Instead, they are right here, superimposed on our Universe but invisible and inaccessible. The other selves they contain really are “you”.
In fact, there is no meaningful “you” at all. “You” are becoming distinct beings an absurd number of times every second: just think of all the quantum events that happen as a single electrical signal travels along a single neuron in your brain. “You” vanish into the crowd.
In other words, an idea that started out as a mathematical convenience ends up implying that there is no such thing as individuality.