Since everything is energy, can fermions and bosons be (theoretically) converted to energy too?
Welcome to PF!
The notion of everything is energy is wrong and is the wrong way to look at things...
Fermions and Bosons are particles that behave in certain ways.
Electrons are the most notable fermions and photons are the most notable bosons.
Given that what is your question?
To extend jedishfu's answer:
Particles have energy - their energy is one of their properties, energy is not an object that could get created.
As a comparison, an apple has a color - and you cannot "convert an apple to color".
Why can't everything be "traced" back to energy when everything was caused by Big Bang?
Isn't Big Bang like a energy-soup eruption?
You have to think of the big bang as particles in very high energy states in a very small space that suddenly expands not that particles are switching from matter to energy and back again. The particles may be switching energy states but they aren't switching to energy.
Look at the square well problem of quantum mechanics:
The particles are behaving like waves and each particle has a specific wavelength and frequency which determines the amount of energy it has in the square well.
Even the spacetime originated through Big-Bang, how does that work?
Figure that one out for sure and I guarantee you a Nobel Prize. Possibly several
The "Big Bang" really has two meanings. First the Big Bang Singularity, which may or may not have created everything and which we do not understand. Second, everything from 10E-43 seconds AFTER the singularity. That's really the "Big Bang Theory" and is quite well understood, with some holes still remaining.
We won't have a complete understanding of this until we have a theory of quantum gravity and even then it may still require something else so I guess you'll have to wait a bit while the physicists catch up.
and Steven Hawking talks about it here:
So Space, Time, Mass, Energy and The Fundamental Forces are separate fundamental entities... These are the most fundamental things, right?
you can;t take out 5 words and call them the fundamental entities, because we don't know what is actually fundamental. Maybe the fundamental forces are a remain of space compactification, maybe they are not.
Well, those and pizza.
But the fundamental forces function differently, even though they were once unified...Also since the exchange particles have been discovered...I don't think that can be the case.
Well, yeah, but by the definitions of today's physics as we understand things, I think he has it right (except for leaving out pizza).
First of all, please define to me what you mean by fundamental then...
Standard Model (for me) is not fundamental because I don't see it as a complete theory - although totally experimentally verified it leaves many windows opened. So how am I supposed to call it fundamental? there is more to be found within...
In addition, if the fundamental forces were once unified, or were once a part of extra dimensions, this would mean that the theory can be more fundamental... The idea is based simply to the fact that in the past, atoms were considered fundamental... then electrons and nucleons... and so on...
Eg if the resulting fundamental forces come from the spacetime compactification, then for me, fundamental would be the spacetime geometry (not the forces)
Yes, my statement does take the Standard Model to show the fundamental particles and I do take the fundamental forces to be fundamental.
Is there any other entity that should be added to the list? Or is the list complete?
Not that I can think of offhand but I would change "space" and "time" to space-time. Thinking of them as separate is classical physics and can cause problems in real world cosmology. It's like thinking of an electron as a particle AND a wave. Actually, it's not either one. It's a quantum object.
By "extra dimensions", you're talking about the curled dimensions, right?
Anyway, the standard model might leave some windows open...but the example you're talking about is definitely not one of them...the exchange particles have been discovered.
Yes that's what I meant by extra dimensions.
What if they have been discovered? The atom has been discovered as well, it's not fundamental. I'm not saying that the particles are composite, but I'm saying there is a deeper meaning to their existence. If the extra dimensions exist, as I noted above, and their compactification gives you the appropriate fields, then the fields are a result of the curled up manifold's geometry... thus they stop being fundamental for me, but they are a result of the spacetime structure.
I am not saying that extra dimension theories are correct...
My problem was with your question about that list of 5 things being the most fundamental things. No they, in fact, are not.
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