Recent content by timpeac

I'm sorry, but I didn't. I said I couldn't see how it could possibly be true, to which phinds replied that it indeed wasn't and this was an oversimplification sometimes provided erroneously by pop science. See the Q and A here http://www.cfa.harvard.edu/seuforum/questions/ in particular the...

I suppose it's true that if the "big bang" theory is very easily grasped if you think of a single point inflating and expanding. If it had been presented to the general population as being an unknown volume wherein every point inflated and expanded then I doubt it would have caught the popular...

Thanks for putting my mind at rest phinds. Yes, I know that you can't provide all the details in pop science, but it would be helpful if they could avoid using terminology that is actually potentially incorrect! Yes the golf ball/grapefruit etc comments muddy the water, particularly if they...

Hello, I have a question about the character of the universe today and its early state. As I understand it there is no consensus as to whether the universe today (the whole universe, not the observable) is infinite, finite, or finite but looped in on itself. It seems to me to follow that if...

Thank you both for your replies. I will think on what you have said. Just one quick follow up question at the moment - While still on Earth at t=0 the travellers will see light coming from AC showing that their clocks say t=-4, and they will therefore infer that "now" is t=0 also for AC since...

Hi Grav-universe - ah I think I follow what you are saying. So if, while on Earth sitting in their spaceship ready to set off, they had a telescope trained on a clock on AC which said t=0, then in the time that they accelerate to 0.8c they see the hands of the clock whip round to t=3.2 and then...

Hi All, I think that I understand (as far as you can!) the ideas behind explaining why two twins have different ages if one travels at near light speed away for a time and then returns to his twin on Earth (the return journey changing the inertial reference frame). I have a related...

Ah yes, I see. I think it's a case of you say tomahtoes I say tomaytoes -the way I was thinking of it is that the person left on Earth considers that for every one his seconds one on the ship his lasts 0.8 (or whatever) as long and so his has contracted. Yours is of course the same view but from...

Hi, Just out of idle curiosity - why do we talk of "time dilation" in terms of special relativity when in fact it contracts which is the opposite? Is there a reason or is it just accepted usage?

But doesn't the situation I described in b) in my original post show that both clocks are indeed running slow in relation to each other without acceleration taking place? Twin b's clock is indeed slower than the person at the star's on comparison when he arrives and the person at the star's...

Thank you all for your replies - they make perfect sense. I was forgetting that just because both twins agree that passing the Earth is simultaneous, and twin a and the person at the star agree that the event is simultaneous this does not necessarily imply that twin b and the person at the star...

Hi, I can see that this topic has been much discussed, but I haven't seen a thread on it with the particular spin I want to give it (just the journey out from Earth). I understand the traditional view of the twin paradox (I think!): Two twins a and b are on Earth and each has a clock. The...

Thanks guys for your replies. I also read Rach's reply and was a bit peeved. I know she's trying to help but you shouldn't assume things. Just to give a bit of background - I am not studying physics. I studied it many years ago and from what I remember when I read that comment in the press it...

Quantum entanglement Hi, I was interested to read this quote http://www.signonsandiego.com/news/science/20060622-9999-lz1c22cause.html" . Have they got that wrong then? It makes it sound like there is meaningful information being transmitted instantaneously since if they could see that...