12481

Physics, Astronomy & Cosmology / Re: Very basic cosmology question

« on: 17/04/2005 00:47:46 »

Rosy, that's a pretty good analogy. At each point in space the expansion is uniform (I think) so the further away any 2 objects are the more space there is between them to expand. I've seen it explained as dots on a balloon. Assume the dots are equally spaced when the ballon is flaccid. As the balloon is inflated the surface between each dot expands uniformly. Therefore neighbouring dots will move apart slower than dots that are on opposite sides. *wonders if, as the universe is at least 4-dimensional, time expands too*

12482

Physics, Astronomy & Cosmology / Re: gravity

« on: 15/04/2005 22:22:25 »

Thanks GSMolin, that's explained it a bit better for me. Strangely enough I managed to understand most of it.Just 1 point, though. Wouldn't a rotating binary system just be 2 dipoles rather than a quadrupole? Or are they the same thing?

12483

Physics, Astronomy & Cosmology / Re: Very basic cosmology question

« on: 15/04/2005 22:16:10 »

DrPhil, you seem to be a very knowledgable person whether or not you consider yourself over the hill.
I was being a bit facetious when I mentioned about them going phut. But can I bring another dimension (no pun intended) to this? If there is enough matter in the universe to cause it to be 1 giant black hole, wouldn't gravity gradually slow the photons down and eventually pull them back?

12484

Physics, Astronomy & Cosmology / Re: Pulling String a Universe Wide ?

« on: 15/04/2005 06:09:51 »

I like your style. Are you as good at cheating in pub quizzes? If so, may I invite you to join my team? heh

12485

Physics, Astronomy & Cosmology / Re: Very basic cosmology question

« on: 15/04/2005 06:07:59 »

AS a matter of fact I have been cornered by a mathematician at a party! Fortunately I was too blathered to take much notice of what he was wittering about
DrPhil I accept Riemanian (excuse my spelling) geometry & can understand that given a certain geometry the universe curves back on itself (saddles & spheres, I believe, have something to do with it). However, I also remember something about a theoretical puzzle about an hotel with an infinite number of rooms and then another room is added. Does that ring a bell with you? I can't remember the exact details.
You'll have to pardon my ignorance on this subject, I am but a lowly doctor of psychology so hence not au fait with anything more complicated than 2+2.

12486

Physics, Astronomy & Cosmology / Re: Very basic cosmology question

« on: 13/04/2005 17:19:59 »

DrPhil, philosophically that argument does not hold water. Infinite implies it's as big as possible & as such it cannot expand. If it expands it cannot have been infinite to start with. It's like the equation infinty+1=infinity.

12487

Geology, Palaeontology & Archaeology / Re: Supervolcanos

« on: 13/04/2005 13:43:12 »

I know it's not a volcano (or, at least I don't think it is) but part of 1 of the Canary Islands is due to fall into the Atlantic at some point. That's predicted to cause a tidal wave that could devastate the Eastern seaboard of the USA

12488

Geology, Palaeontology & Archaeology / Re: Horizontal vs. Vertical

« on: 13/04/2005 13:37:37 »

Do arthropods get lockjaw?

12489

General Science / Re: Why are the aliens in Star Trek humanoids ?

« on: 13/04/2005 13:34:43 »

All the aliens in Star Trek being humanoid was explained in 1 episode. A super race of beings seeded the galaxy with a common DNA

12490

Physics, Astronomy & Cosmology / Re: Pulling String a Universe Wide ?

« on: 13/04/2005 13:29:17 »

realmswalker - that's cheating! heh

12491

Physics, Astronomy & Cosmology / Re: gravity

« on: 13/04/2005 13:28:27 »

realmswalker - I appreciate that the Earth is in motion, as are the solar system & our galaxy: but that doesn't detract from what I said. I'm also aware that physics postulates the possibility of Gravitons. In fact, are gravitons not essential if gravity is to be combined with the electroweak force in the theory of everything?

12492

Physics, Astronomy & Cosmology / Re: Very basic cosmology question

« on: 13/04/2005 13:20:25 »

DrPhil - I'm aware of the fact that the universe isn't expanding into anything as there's nothing for it to expand into. But when it's said that at a given time after the big bang the universe was whatever size, there must have been an edge or it would always have been of infinite size. That clearly cannot be the case.

12493

Physics, Astronomy & Cosmology / Re: Very basic cosmology question

« on: 12/04/2005 12:12:58 »

I've read those links & i'm just as confused as ever. So, answer me this... if photons travel at the speed of light there must come (or have been) a time when some reach the edge of the universe. What happens then? Do they just go phut? Or do they cause the universe to start expanding at the speed of light with the photons forming the edge?

12494

Physics, Astronomy & Cosmology / Very basic cosmology question

« on: 11/04/2005 13:41:18 »

There's something I've been confused about for years but as yet I've had no satisfactory answer to. Cosmologists say we can now see objects 12 billion lightyears away. Now, if that light has taken 12 billion years to reach us, the objects concerned must have been almost that far away (minus the expansion of the universe)when the light started its journey. But surely, 12 billion years ago the universe wasn't anywhere near large enough for any object to have been that far from any other object: so how come we see them now? Wouldn't the light have gone way beyond us by now? Can anyone help me understand this?

12495

Physics, Astronomy & Cosmology / Re: Pulling String a Universe Wide ?

« on: 11/04/2005 15:05:08 »

Tries to imagine an interstellar tug-of-war. Could you pop off for a pint before you felt the other team pulling the rope?

12496

Physics, Astronomy & Cosmology / Re: gravity

« on: 11/04/2005 15:02:07 »

It must be near-instantaneaous otherwise when you dropped something it would hover in the air for a while before falling to the ground

12497

General Science / Re: Fractal-sorta

« on: 11/04/2005 14:56:25 »

oops! I meant to put "do while length>1"

12498

General Science / Re: Fractal-sorta

« on: 11/04/2005 14:55:31 »

It's quite straightforward if you're happy to use just up, down, left & right for the direction of the line and use them sequentially. It'd be something like:-

startfunc:
    length=startlength
    direction={up, right, down, left}
    horiz=true
    do while l>1
           locate(x,y)
           drawline(length, direction)
           horiz=horiz NOR horiz
           length=length/2
           if horiz
                x=x+length
           else
                y=y+length
           endif
           direction(next)
     enddo
           
Using random angles for the direction changes would make it more fun!

12499

Physics, Astronomy & Cosmology / Re: Hypothetical research questions.

« on: 11/04/2005 13:28:01 »

I haven't got a clue of the maths etc involved but I like the idea. It would make 1 hell of a weapon too!

Good luck with it.