Faster than light

[MajinVegeta]

What is energy???

 

It is a conserved quantity (like angular momentum) of which there are different types

[KHinfcube22]

Originally posted by MajinVegeta

What is energy??? Does it have mass????

 

I'm going mad! I don't know what it is, and I talk about like I do!!

 

The simplist way to put it is Energy is Energy. The definition my physics teacher uses though is that energy is something that can cause movement. So to ask if energy has mass, you'd have to specify, what type of energy.

[JaKiri]

Originally posted by MajinVegeta

What is energy??? Does it have mass????

 

I'm going mad! I don't know what it is, and I talk about like I do!!

 

Energy doesn't have mass.

 

Mass is a form of energy.

 

You know the basic types of energy you're taught; 'heat, kinetic, gravitational, electrical' and the like?

 

What they are is derivitives of the basic kinds.

 

Kinetic Energy is Kinetic Energy. It's the only way to describe it, and is, in terms of special relativity, the differing energies from being defined in different rest frames (but that's a really overcomplicated way of saying it.)

 

Heat is another form of kinetic energy, it's just that the objects moving are at the particle scale, and the movement is very small and in random directions so you don't notice it with your eyes.

 

Electrical is another form of kinetic, essentially.

 

Gravitational, and the kind you get from magnets, etc are examples of potential energy.

 

Have you seen an equation like this?

 

F = GMm/r^2?

 

That describes the attractive force between two masses due to gravitation (the masses being M and m, G is the gravimetric constant, r is the distance between them).

 

The potential energy of a system (be it with whatever fundamental force [i'll describe them at the end]) is simply the amount of energy required to move an object into a field.

 

It's like pushing two magnets together.

 

The third kind of energy is mass; remember the equation E = mc^2? That's a basic equation defining how much energy represents that much rest mass.

 

All of these forms of energy (except kinetic) can be represented by a 'carrier' particle;

 

the best way to define carrier particles is like this.

 

You're in a boat, and there's someone in another boat close by. You throw something to them, and your boat moves away from theirs due to conservation of momentum. It's like that with carrier particles, except you can be attracted as well as repelled.

 

The carrier particles exist for the four basic forces, which are:

 

The Electromagnetic

The Weak Nuclear Force

The Strong Nuclear Force

Gravity.

[Preston Taist]

Any word on if we've witnessed a graviton yet?

[KHinfcube22]

Originally posted by Preston Taist

Any word on if we've witnessed a graviton yet?

 

Don't know, don't care.

 

What would happen if we flung 159 positivley charged hydrogen atoms at each other?

[JaKiri]

Originally posted by KHinfcube22

Don't know, don't care.

 

What would happen if we flung 159 positivley charged hydrogen atoms at each other?

 

They'd bounce off eachother, for the most part.

 

ps.

 

We're not going to have much word on the graviton until the LHC is completed.

[JaKiri]

Apologies from earlier in the thread go to whoever I was arguing with over singularities.

 

Forgive me for forgetting all my mathematics.

 

Although the Event Horizon is also a singularity, just a removable one.

 

(Maths to follow for those of you who like this kind of thing)

 

The eqn we're looking at is

 

g^11 = (-1)/(1-2:lambda:/r)

 

Obviously, you'll get a singularity at r=2:lambda:, but this can be removed by an appropriate coordinate transformation and is designated as such.

 

In fact, r=2:lambda: gives us the location of the event horizon, but we can leave that aside at the moment.

 

The other interesting case is that g^11 => 0 as r => 0.

 

This seems perfectly trivial, until you consider that space time curvature is by the double differential of that equation (with respect to r), and so you find that

 

curvature ~ :lambda:/r^3, which will, when r=0, give infinite space time curvature as was said earlier in the thread.

 

ps.

 

It was faf I was arguing with, although his question 'What is the mass of a singularity?' is entirely pointless.

 

This reply sponsored by Mathematical Methods for Physics and Engineering by Riley, Hobson and Bence for reminding my ignorant brain of what a singularity is.

[Radical Edward]

Originally posted by Preston Taist

Any word on if we've witnessed a graviton yet?

 

not yet, they are just hypothetical at the moment, as it would fit in with a "quantum model" Merging QM and GR is proving elusive.

[Radical Edward]

Originally posted by KHinfcube22

What would happen if we flung 159 positivley charged hydrogen atoms at each other?

 

as MrL says, they would mostly bounce off one another. however if you are interested in the stability of atoms like that, look up the semi empirical mass formula.

[Giles]

what an excellent thread. if only people got lots of silly ideas about the hardy-weinberg law i'd be set to look clever too.

[JaKiri]

Originally posted by Giles

what an excellent thread. if only people got lots of silly ideas about the hardy-weinberg law i'd be set to look clever too.

 

I heard that it made sheep go pink!

[Giles]

Assuming random mating and no selective dis/advantage to being pink, and that pinkness is controlled by a single locus, it makes the same number of sheep go pink as were pink in the last generation, after f(1).

 

Huzzah!

 

EDIT: damn, it's got to be a dimorphic locus too. forgot that part.

 

Population genetics: don't do it!

[JaKiri]

Controlled by a single locust?

 

You're talking crazy speak!

 

To Pseudoscience to you!

 

ONLY I UNDERSTAND SCIENCE

[KHinfcube22]

Originally posted by MrL_JaKiri

Controlled by a single locust?

 

You're talking crazy speak!

 

To Pseudoscience to you!

 

ONLY I UNDERSTAND SCIENCE

 

And only I understand the meaning . To sreve ME! It even says so in the bible. "Though shall serve KHinfcube22." Its in chapter Appollo

[BPHgravity]

Hasnt the universe expanded faster than the speed of light? The universe is obviously larger than how long it would have taken light to get across it.

 

Am I making any sense?

 

:confused:

[blike]

Originally posted by BPHgravity

Hasnt the universe expanded faster than the speed of light? The universe is obviously larger than how long it would have taken light to get across it.

 

Am I making any sense?

 

:confused:

 

Yea, see here http://www.biols.susx.ac.uk/home/John_Gribbin/cosmo.htm

 

I'm not sure how many other theories there are to account for this problem, though.

[cHIs-]

Sorry i havent read all the other posts, i really should, but i was just thinking about traveling faster than light... if this were possible, and hopefully maybe one day it will be...

If you were traveling faster than light and you reached your destinatin, would light travel up behind you? what some posts are saying is that you would be traveling in time, future or past, but how is that.. this is confusing me and im thinking about it right now, so if you traveld faster than light and say came to a planet like earth where light is here, what wold it be like arriving before like, and they already have light, its confusing im confused,

 

Ill try explain better what i think um...

We have light right now, and if a ship was traveling to us faster than light and it hit us, there would already be light here, what about the light behind it that it was traveling faster than? how would it be in the future or past? I really need to read more about it, ive suddenly taken an interest in Astronomy and space travel, i dont know where to start, and i havent had much luck in school considering i left young, and im only 16 and i was never very good at maths... is it possible for me to learn? i want to...:/

[cHIs-]

If we were traveling faster than time/light, and we arrived at are destination before light, how long would it take for the light to come and hit us, i made a little flash animated cartoon of what i thought, i aint gonna show you becuase i know im wrong, i just was wondering what would be happening in the time where light isnt there. I really want to understand this more!

[JaKiri]

Light always travels at c relative to you (ignoring the effects of the medium), no matter what speed you're going at.

 

The current load of ideas of how to acheive translight speeds usually involve warping space/time so you only go faster than c to observers, but not relative to the space you're occupying.

 

If you see what I mean.

[cHIs-]

im trying to make sense of it... but whats C?

[JaKiri]

c (It's LOWER CASE GUYS) is the speed of light in a vacuum, and is defined as 299792458ms^-1

[KHinfcube22]

What would happen if one traveled at C in a car, then flipped on the headlights?

[Radical Edward]

Originally posted by KHinfcube22

What would happen if one traveled at C in a car, then flipped on the headlights?

 

you can't travel at c, because you have mass. stick it in the lorentz transforms and see

[JaKiri]

Originally posted by KHinfcube22

What would happen if one traveled at C in a car, then flipped on the headlights?

 

Even if you could travel at c (LOWER CASE), which you can't, the light would still move away from you at c.

[KHinfcube22]

Originally posted by MrL_JaKiri

Even if you could travel at c (LOWER CASE), which you can't, the light would still move away from you at c.

 

Just so I know, for I don't want to go all over the place, why can't we travel at c? And please don't say "

Because one needs inf. energy to travel ay c." If one needed inf energy, then how does LIGHT do it? Can't we jusst find out how fast light moves, how much light ways, and make up some equation to find out fast it would need for us to go?