If you could ask the biggest questions you can think of, what would they be?
Why is there something rather than nothing?
What caused the big bang? What is dark matter and energy?
What if the answers to these and other big questions could emerge naturally
from just one theory? What would this theory
look like? What would it be called? It would truly be a theory of everything.
It would show us that perhaps the building blocks of all particles and forces in the universe
are quite simple. It could not only give us the answers to some of the biggest questions,
but also finally reveal the true nature of reality.
But is this all wishful thinking? Is such a theory really even possible?
What makes us think that such a theory really even exists?
Well, we only have to look at the past history of science going back only a few hundred years
to see that we humble humans have been able to find some successes
in unifying seemingly completely unrelated forces and particles to a more basic set of principles.
What are some of these unifications that we have already found?
What are the unifications that are yet to be found? And what would a true
theory of everything look like if we were to discover it?
Stay tuned because the answer to that important question that’s coming up right now…
Before I talk about the theory of everything, let me tell what inspired me to make this video.
I watched a documentary on Magellan TV, today’s sponsor called, “Seeing the beginning
of time” – It looks at technologies scientists are using to find out how galaxies were formed
in the universe. This got me thinking about how the universe came to be in the first place.
You’ll find thousands more incredible documentaries like this on Magellan TV.
It’s a streaming documentary service created by the filmmakers themselves.
They dive deep into subjects like history, culture, science and technology. And you can
watch it anytime on any of your devices, including many in 4K.
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right now. If you click on the link in the description, you will get a free one month
trial. I highly recommend Magellan TV, but be sure to click the link in the description.
If a really curious child was to ask you,
“why is the sky blue?” – The answer you might give him is because blue light scatters more
in the air than other colors, and you see the more scattered color.
What if he kept asking why? “Why does blue light scatter more?”
Well that’s because blue light has more energy
and vibrates particles faster than other visible colors.
“Why does blue have more energy?” Well, it has a shorter wavelength.
“Why does it have a shorter wavelength?” Well, that’s because all light travels at
the same speed, and in order to carry more energy it has to have a higher frequency.
“Why does all light travel at the same speed?” Well, that’s just the way the universe works.
“Why does the universe work that way?”
I don’t know kid, go watch some Arvin Ash videos or something. He’s got you!
A theory of everything would ideally allow us to answer all why questions, so that even
the most curious child or adult would be fully satisfied.
What would a theory of everything look like? At a minimum, it should contain or provide a
theoretical basis for at least two things – a fundamental building block or particle
of some kind from which all other particles can be derived, and a fundamental force,
from which all other forces can be derived.
At one time atoms were thought to be the fundamental building block, then
in 19th century, protons were discovered, then in the 1960s. protons were found to be
made of even more fundamental particles called quarks.
These and all the other particles of the standard model are currently thought to be fundamental,
and cannot be further divided. But we should probably expect that this is not the final answer.
Likewise, we don’t currently have one fundamental force. Traditionally, we talk about 4. The Strong
force which keeps the protons and neutrons glued together in the nucleus, electromagnetism
responsible for all chemistry and electricity. The weak force responsible for some kinds of
radiation, and gravity which keeps us glued to the earth and earth in orbit around the sun.
Can the forces be unified? I think it is possible if we go by historical precedent, because we have
united forces in the past. For example, up until the 17th century, it was thought that the motions
of heavenly bodies were controlled by a different mechanism than the motions of objects on earth.
However, in 1687, Isaac Newton showed that these two phenomena were ruled by one principle – the
principle of universal gravitation. He unified terrestrial gravity with celestial gravity.
The idea that the same force that governs
the motion of objects on earth, is also the same one governing
the motions of planets is obvious to us now, but it was not at all obvious prior to Newton.
Similarly, prior to 1865, magnets were known to exist, and electricity had also been discovered.
But it was not obvious that they were connected. James Clerk Maxwell found the connection and
worked out the equations describing the relation between electricity and magnetism,
or as we came to call it, electromagnetism. These are now called Maxwell’s equations.
He also found that light was caused by the same phenomenon. So light, electricity, and magnetism,
which had appeared to be 3 completely different phenomena or forces, were now united. Later
chemistry was also determined to be an electromagnetic phenomenon.
We now know that Electricity, magnetism, light and chemistry
are really manifestations of a single force. But this was not obvious in the past.
Universal gravitation and electromagnetism were the two great unifications of history.
More recently, in just the 20th century, quantum mechanics came along
and unified atomic theory and Newtonian mechanics.
Mass and energy were unified by special relativity in 1905 by Albert Einstein. 10 years later,
Space, time, and gravity were unified by general relativity also by Albert Einstein.
In the 1940s, Special relativity, quantum mechanics and electromagnetism were unified
with the theory of quantum electrodynamics mainly by Dirac,
Feynman, Schwinger and shin ichiro Tomonaga.
Then in the 1960s, QED was unified with the weak force, with the advent
of the electroweak theory by Glashow, Salam, and Weinberg.
And less than 50 years ago in the 70s, Just like QED describes the mechanism
of electromagnetism, QCD or quantum chromodynamics was developed. It describes the mechanism of the
strong nuclear force. This is the force that hold the quarks inside protons and neutrons,
and glues them together in the nucleus of atoms.
One of the biggest questions in science is, how is the Electroweak force related to the
strong nuclear force. In other words, how are QED, the weak force, and QCD united? The
potential unification of these has been given the name, the grand unified theory, or GUT.
On the other side, if we can combine quantum mechanics
and general relativity, we would have a theory of quantum gravity.
You might ask, why does gravity have to be united with quantum mechanics? After all, didn’t Einstein
show us that gravity is due to a smooth curvature of space time. Yes, but Einstein’s equations
are incomplete because that idea of spatial curvature doesn’t work at the quantum scale.
The simplest example of this is inside a black hole where a singularity is thought to exist.
This is a point concentrated with so much mass and energy, that it forms a hole in space time
according to the Einstein’s equations. In other words, General relativity doesn’t work here.
At this scale, gravity, instead of being incredibly weak in our large dimensions,
becomes just as important as the other forces. But to describe this, you have to have a completely
new theory describing how gravity works with other forces. We need a quantum theory of gravity.
Now, if we can combine the grand unified theory
with quantum gravity, we would have a strong candidate for a theory of everything.
But we would need to curb our enthusiasm, because even after such a momentous breakthrough,
our work may still not be done. After we unite all these forces, we would still need to explain how
the big bang came to be and what happened prior to the big bang. This could involve an even more
fundamental theory that involves multiverses, or multiple dimensions or something else.
Also, let’s not forget that all the matter we know is only about 4% of the entire universe.
The remaining is dark matter and dark energy. So any theory of everything has to be able to explain
these. It is quite likely that the standard model as we know it today is incomplete,
if for nothing else than the fact that it does not explain either dark matter or dark energy.
And finally, there is the conundrum of matter-antimatter asymmetry. We don’t
understand why the universe is made of matter. Einstein’s theory of special relativity says
that energy can turn into matter. But when energy turns into matter, it should make an
equal amount of antimatter. And that’s what we think must have happened after the big bang.
But how and why did the antimatter disappear? The universe somehow got rid of most of it
and left only matter. We don’t know how that happened. So we have a ways to go.
So are there any good candidates for a theory of everything? The most popular is String theory,
which posits that all particles are fundamentally different vibrations of
a single entity – string-like objects. The vibrations of these objects in 6-7
hidden dimension is what we perceive as the various fundamental particles
and force carriers of nature. I made a video about that if you want to check it out here.
But there is a lesser known theory that I find very intriguing,
and that I think you should know about, it is called Quantum Holonomy theory, or QHT.
It posits that nature is fundamentally the mathematics of moving things in empty space.
Some of its implications are that all forces are quantized, but gravity is not. So quantum
gravity does not exist. It also shows that there is no infinite hole inside black holes. And the
Big Bang could not have come from nothing. It was probably more like a big bounce.
This theory and how it fits with our current understanding of the universe,
will be the subject of my next video, so stay tuned, you won’t want to miss it.
I’d like to thank my generous supporters on Patreon and Youtube. If you like my videos,
consider joining them. And if you have a question post it in the comments below,
and I will try to answer it. I will see you in the next video my friend!