>Why are there 4 fields (strong nuclear, weak nuclear, electromagnetic, gravity).
Why is it that certain pairs of things in the universe can influence each other at a distance, and other pairs of things cannot? (For example, a musical instrument resonating at the fundamental pitch of a wine glass can vibrate and/or potentially shatter the wine glass).
Why are there 4 fields? Well, potentially there are an infinite number of fields -- but each one's "sphere of influence" is "local" to a specific scale. Some span the smallest units of distance; others span much larger scales...
>Why does gravity affect the other three?
Why do non-prime integers have multiple factors that divide into them; Conversely, why can larger integers be made by multiplying two or more integers; Think of this with respect to vibrations; with respect to waves; if something in the universe is affected by or affects something else, generally speaking it's because they vibrate sympathetically at some level or other. Also, it's possible that the other three forces are influenced by gravity because gravity is the fundamental constituent of them, that is, they are all created by gravity in various different configurations, just like larger integers are created by multiplying smaller ones, or larger patterns are created by smaller ones.
In other words, strong nuclear, weak nuclear, and electromagnetic forces -- ARE gravity -- in its various modes/oscillations/vibrations/patterns/configurations/structures, etc.
Phrased another way, Gravity is the Y Combinator of the other forces, the central low-level pattern from which the other higher-level patterns are built...
>What even is a 'field'.
In classical physics, you have the particle/wave duality. Basically, one is the other, depending on frame of reference.
That particle wave duality (I've determined) is actually a particle/wave/field TRINITY.
That is, particles ARE waves (depending on how you look at them), waves are particles (depending on how you look at them), BUT ALSO waves are fields (depending on how you look at them), and fields are waves (depending on how you look at them), and fields are particles (depending on how you look at them) and particles are fields, again, "depending on how you look at them".
Google "Starlings". A single starling at rest is a particle, in motion, it's a wave, and many of them together moving in unision, that's a field.
Also (and this is the advanced lesson), you can have various degrees of recursion in this, for example, a whole field of starlings could be viewed as a single particle, then that could comprise multiple particles if teamed up with other fields of starlings, and then those things could move like wave.
Think nested particles/waves/fields -- inside of other particles/waves/fields.
Also, the smallest unit of space (to implement all of the others), DOESN'T NEED TO PHYSICALLY MOVE; that is, it only needs to state-change, like a pixel, if it were a magnet, it could change from a North Pole to South Pole (or possibly neutral), if charged, the charge could go from positive to negative and back, if a region of force, the force could push one way and then the reverse, etc., etc.
But the smallest units of space... DON'T NEED TO PHYSICALLY MOVE. There's absolutely no motion on a TV or monitor screen; these are ILLUSIONS created by the mind's observation...
>Why does gravity affect the other three?
Asked and answered. See above.
>What is time? What is space? What is quantum entanglement?
You forgot "distance" and "velocity". What are they?
Space can be defined in terms of speed (velocity) and time, i.e., if you travel 60 MPH for one hour, you've travelled one mile.
Time can be defined in terms of distance travelled relative to speed (velocity) -- if you travel at 60 MPH, and you don't know what time it is or when you started, but you know you've travelled 60 physical miles, then you know you've travelled for one hour.
And of course, speed (velocity) can be defined in terms of time and space.
But the problem is, try to separate one from the other two and define it by itself -- you can't do it. You need the other two to define the third one. Which means that they are all interrelated, and possibly aspects of the same basic thing...
>Why is there a universal speed limit?
There is none; this is fake news; "speed" is always relative to local distance, which is relative to scale. In the time it takes your local watch's second hand to move one second, Cesium will have osciallated 9,192,631,770 times in that second. Elephants move faster than Ants, but they're also physically larger. The Earth rotates at 430 meters per second, much faster than an Elephant walks -- but the Earth is much bigger in scale. The Earth revolves around the sun at 30 Kilometers/second but again, that's a larger scale. The Sun's motion in space, relative to the gravity well in our galaxy which it revolves around will be much faster than that, but again, it's relative to scale.
>Why do you need an 'equal and opposite reaction' to gain momentum, why can't you just convert angular energy directly into linear energy in a single direction?
If you were in outer space, pitch-black empty space, and there were no planets, stars, or other celestial objects by which you could compute your rate of speed, how would you know that:
A) You were stopped? B) That you weren't going at some rate of speed? C) That you weren't travelling at INFINITE SPEED?
In other words,
1) HOW WOULD YOU KNOW YOUR RATE OF SPEED, and
2) IF YOU COULD NOT KNOW YOUR RATE OF SPEED, THEN WHAT WOULD THE DIFFERENCE BETWEEN THIS STATE, AND THE STATES OF BEING STOPPED, TRAVELLING AT A SPEED, AND TRAVELLING AT INFINITE SPEED BE?
In other words, it's paradoxical. In this state 0 speed (stopped) = some speed = INFINITE SPEED. How would you know the difference? You couldn't...
Say it with me, "Speed is RELATIVE to a FRAME OF REFERENCE", if you're moving at a rate of 60,000 MPH away from a planet, that planet is equally-and-oppositely moving at a rate of 60,000 MPH away from you (and it didn't invest any energy, not one drop, to gain that speed! <g>)
>Why is there a universe at all, instead of nothing?
Why are there billions of web pages, book pages, and other written documents in English, and yet, there are only 26 characters in its alphabet (or 52 if you count lower-case letters). Heck, 53 if you count 'space' as a character.
That's one heck of a lot of things constructed from so small a set of repeating entities. <g>
Etc, etc.
>But as far as 'what is heat', you should read more, or just google your questions.
I quote to you Socrates: "The true knowledge consists of knowing that you know nothing".
>You might be surprised at how many other people have asked the same questions, and then set out to answer them, but with evidence. It's called "Science".
Yes, but Science and all Scientific Evidence -- must be consistent with itself.
It's called "Logic".