Why does concept of "before" and "after" depends on lightspeed?

[Nacelunk]

Why does concept of "before" and "after" depends on lightspeed?

Also here is example - an objects is flying in a perfectly dark (without photons) area. What would be the maximum speed for the object and what would happen if it turned its engine on incredibly powerfull mode and tryed to overcome the lightspeed?

[Klaynos]

The existance of photons (or lack of) does change the fact no massive object can not travel at c.

[Nacelunk]

What if try?

[timo]

Why does concept of "before" and "after" depends on lightspeed?

I don´t really know the "concept of before and after" but I can guess what you are talking about:

When two events in spacetime can be connected by a path light could take (mirrors allowed, shielding of light not allowed - the definition is not really about light), then you can tell that the two events have a definite time order. If you cannot, than you cannot say so as you will always find a coordinate system in which the the time order will be reversed.

For understanding how two events can have a different time order, think of time as a direction in spacetime (the time I´m talking about here actually is - curvature aside). Put two objects on your table. When you look at them you can hopefully tell which one is left of the other. But when you look at the objects from a different direction, the order which of which being left might have changed. It´s not so much different with time.

The harder thing within this analogy is to explain why some events will still always have the same time-order. The reason is that the time-direction is not completely arbitrary but I don´t have any good analogy at hand for this right now.

Also here is example - an objects is flying in a perfectly dark (without photons) area. What would be the maximum speed for the object and what would happen if it turned its engine on incredibly powerfull mode and tryed to overcome the lightspeed?

As said, the lightspeed-barrier has nothing to do with light. Light just incidently has the property to travel with the velocity of the barrier ... well, and that´s why the barrier is called lightspeed. Absolute zero temperature would be the same even if Lord Kelvin hadn´t become a scientist.

[Nacelunk]

I read an article where author was talking about this: imagine a big mirror. This mirror reflects everything that happens in someones life. Then, you go and sit into a spaceship which can overcome lightspeed. You fly directly from the mirror (in exact direction which the reflected photons go). Gradually you overtake the photons. First you see the photons which "show" us very recent events (that guy is old) then you see "older" photons that show young guy. Basicly time is going back.

Is this what you mean saying time is relative as well as space?

[JustStuit]

Time is relative but you cannot go faster than light. Light goes the same speed relative to anything.

[Nacelunk]

cannot go faster than light

What if I try? (Without any mirrors)

[JustStuit]

The closer to the speed of light, the more massive you get and the more energy required. This reaches a limit, the speed of light (gasp), which cannot be passed or achieved by an object with mass. Essentially, it would take infinite energy.

[Nacelunk]

The closer to the speed of light, the more massive you get

why?

[JustStuit]

why?

Look up "special relativity"

[Nacelunk]

Look up "special relativity"

When do I learn it in school?

[JustStuit]

You might touch on it in Physics (hon) and in AP (probably). I'm still in high school but I'm sure they teach it in physics in college and when you take higher physics they are sure to teach it.

[Nacelunk]

Physics (hon)

What grade?

[JustStuit]

I'm in 11th in Physics honors. The teacher very briefly metioned this but most of my learning takes place out of class. If you want to learn about it I suggest getting a book or looking it up online. Depending on how far you are in school, it might be a while before you learn it.

[Cap'n Refsmmat]

I'd suggest a book on special relativity. I'd recommend something like The Fabric of the Cosmos, although it is a rather complex book and you may find it hard to understand depending on how much English you know. Take a look at it at a bookstore or something before you get it.

 

There are many other books and articles that cover special relativity, and I'm sure you could find a good one.

[Nacelunk]

I suggest getting a book or looking it up online.

I will

What are you learning in Physics 11 Honors and how does it differ from regular one?

[Nacelunk]

To Cap'n Refsmmat

I guess. I must learn english perfectly before I can read hard scientific books. I think I'd rather find something in Russian

[JustStuit]

We learned kinetic motion in two dimensions, forces, work, power, electromagnetism, and gravity. Honors goes quicker and is more in depth. I think it also goes further into more complicated physics but not by too much.

[Klaynos]

I learnt quite a bit about special relativity when I was 17/18 in college (the UK term for college which I think equatest to high school in the US)

 

I'm sure you will be able to find a good book in russian about it Good luck.

[[Tycho?]]

I didn't do any relativity in high school. Or university so far for that matter. But just looking it up online and some books will provide you will at least a conceptual gasp of it, if not necessarly a mathmatical understanding.