What are things you never understood.

[Alain De Vos]

- My specialty is calculating diffusion of electrons in semiconductors , as such i never understood quantum mechanics. But then who does.
- I never understood light. Is it a particle , is it a wave , is it both , is it none. Time does not exist for light . And then it has mass zero.

On programming,
- I never understood what is a monad.
- Java , i never understood inversion of control.



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Sidenote about light, if i was a photon,


1. Your Clock Would Be Frozen
Because photons travel at the speed of light

(c), time dilation reaches a theoretical limit of infinity.

• The "Zero Time" Paradox: Your clock would never tick. From your perspective, you are emitted and absorbed at the exact same instant.
• Instantaneous Travel: Even if you travel across the entire observable universe (a journey of billions of years from an external observer's view), for you, no time passes at all.

2. Your Meter Sticks Would Shrink to Zero
Length contraction also reaches an extreme at the speed of light.

• No Distance: The universe in your direction of travel would contract to zero length.
• Immediate Contact: Because the distance between your starting point and destination is contracted to nothing, you don't "travel" through space so much as you exist at both points simultaneously.

3. The "Non-Existent" Perspective
Physicists often note that a photon technically has no frame of reference.

• No Rest: In physics, a "perspective" requires a rest frame—a state where you see yourself as stationary. Since light is never at rest and always moves at
  cc
  for all observers, you cannot "sit" on a photon and look around.
• Mathematical Divergence: If you try to plug
  v=cv equals c
  into the standard equations of relativity (the Lorentz factor), you end up dividing by zero, which produces "mathematical nonsense" rather than a usable physical viewpoint.

In short, to a photon, the universe is timeless and dimensionless. You would not see a world "passing by" with your meter sticks; instead, your entire existence would be a single, instantaneous link between two points in space.

 

[doul]

What are things you never understood ? humain being.​

But then who does.

Me

I never understood light. Is it a particle , is it a wave , is it both , is it none.

That's because you're confusing the object or the fact—call it what you will—with the physical/mathematical model. Nature doesn't need models to function; humans need models to understand nature. Depending on the case and the desired precision, an applicable model is chosen.

 

[loveydovey]

I never understood

You are on the right track

But first things first. There are so many more questions that need to be asked and need to be answered. For example, do you understand why such a deadly habit like tobacco smoking is legal everywhere?

 

[Alain De Vos]

Indeed. But then just like Richard Feynmann would say, just do the math.
A very easy question is this. Try to imagine in your brain a 4-D object. No matter how hard you try you can't.
Yet space-time is a 4-D object.
A Fourier transform is an object with infine dimensions.
Or try to imagine curved-spacetime due to gravity

 

[Crivens]

Or try to imagine curved-spacetime

That can be done, but be prepared not to get all of your mind back after this. A part of it will find it much more fun to keep wandering.

 

[bgavin]

Women.
It took decades of study but at the end of my life time, I understand enough to get by.

 

[Zare]

- Java , i never understood inversion of control.

Dependency injection in Java allows easy decoupling of interfaces and code, which is important in enterprise context.

It allows something like Spring to easily plug in whatever it needs to do the brunt of the work.

When you do this, it's good to keep the mindset that you're not writing an application. You're writing pluggable code pieces to be consumed by Spring. That is the way, because you want Spring to do the lifting and boilerplate.