RichIsnang

Of course, so what exactly emits the photon?

When a charged particle emits a photon carrying the electromagnetic force, and it repels another charges particle, what exactly emits the photon? I think it's the quarks that make things charged so I assume they make say a proton and a neutron differ but How is the composition of quarks different?

Why don't we have a QFT for gravity? Is it because gravity is attractive and the force carrying particles will have to travel out from the centre of mass against the pull of gravity? Which may slow them.

I was under the impression that this was a discussion forum rather than an advertising site...

As far as I know, it doesnt have an opposite. There are many measures that don't have opposites, as mentioned earlier, temperature. How does this need 2 pages lol

Of course

You can also work in 101 dimensions in maths, but that's irrelevant Looking only at one dimension, you can return to the same point in spatial dimensions but not the time one, When looking at them all combined or space-time, you cannot return to the same point in spacetime, but only because time disallows this

Interesting, if the sun was removed, would we continue to spin round nothing for 8 minutes?

Technically as you walk down the road, you are travelling back in time a small amount, wether we can abuse this fact is I feel unlikely, but still possible, I feel that this is a law that will not be easily messed with, but then you could say the same thing about the laws of electromagnetism and I'm sure they did back when they weren't fully understood I imagine we will not be able to abuse these laws for a good while yet tho as it will take very advanced spaceships to do so

Time most probably is a dimension, but why is it different and what makes it different to the rest? maybe we need to redefine our notion of dimension, if we are calling two different things the same thing

Yes but you can turn around in the line of distance and go the other way, you cannot do that with time.

dr rocket, you say that dimensions are a degree of freedom, in the spatial dimensions, we can theoretically travel anywhere, up down, left, right, forwards, backwards but we can only go forwards in time and we cant do that at will. so how much freedom do we have in the time dimension?

Space has always been expanding as long as the universe has been around, also time has always moved forwards as long as the universe has been around. Einstein linked space and time in his view of space-time, maybe the universe expanding and time moving forwards are linked? Gravity causes objects to accelerate, get faster with time, as space-time gets warped. Thoughts?

If an asteroid or a comet Were on a collision course with earth, of diameter ~300m, and we fired a hydrogen bomb at it, would it be destroyed? And is rock harder to destroy than ice? ( I guess it is)

Thanks timo

Why don't positrons annihilate with electrons in a cloud chamber?

Of course, hence 50 light years

Cool thanks

im rich and im new i love how this is a science forum and people are like 'i know its sad, i like science and maths' no its not! science and maths are great and i want this to be an environment where we can all express than and have a good ol' chat about it

If somebody other civilisation on another planet started to look at the sky in great detail, what would they see coming from earth? Would all our radio waves and other such electromagnetic radiation be visible across several light years? Or would our planet just look like a ball of rock

I see, the only thing I don't get is how 'In relativity, a particle of mass m can reach an arbitrarily high kinetic energy even for velocities <c.'

Ah, i see, thanks timo How do we work out the kinetic energy of a particle in relativity? And how does a particle have higher kinetic energy than its velocity would suggest?

i see your point i understand the difference between acceleration and velocity. the acceleration due to gravity on the earth is 9.81m/s^2 is it not? and the escape velocity is measured in m/s is it not? (for earth 11000m/s) and that was a claim i thought. you say a point source obeys newtonian gravity, i would say that a black hole is the closest thing we are ever going to get to a point source seeing as all its mass in concentrated in a single point? i thought black holes were predicted by newtonian gravity? how do they differ if i am wrong? What is the acceleration at the schwarzschild radius of a black hole?

The units for acceleration are m/s^2 That is the unit I use

What is the acceleration at the schwarzschild radius of a black hole? is it 3x10^8? ©? if it is, what is the acceleration at 1m below the radius? more than the c? of course gravity obeys a 1/r^2 law