1

Plant Sciences, Zoology & Evolution / Is the body size of a species related to the size of a group of that species?

« on: 18/11/2008 05:36:04 »

Hi,

this is a question based on a memory of a biology teacher back when I was at school.

I'm pretty sure she said one day that there is a linear relationship between the body mass of individuals in a species and the average size of a group of that species.

As I remember, she put a graph up on the OHP with average body size on one axis and average group size on the other and there were several points plotted each representing a mammalian species, I think.

Although it was a line of best fit and the points were not all very close to the line, there did seem to be a relationship using the points that were plotted.

It was important because humans apparently fall at about 130 individuals per group given our body mass, which seemed like a nice social group to me, and it was this incident that convinced me that this is a true and natural (albeit flexible) fact.

However thinking about it, I'm not sure if it is.  I've had a search on the internet and don't seem to be able to find any research on this fairly simple relationship.

Can any biologist out there help?

2

Physics, Astronomy & Cosmology / Specific Question about Relative Time

« on: 06/11/2008 17:55:08 »

That's exactly what I thought.  Cheers Doc!

3

Physics, Astronomy & Cosmology / Specific Question about Relative Time

« on: 06/11/2008 17:44:04 »

This is a question about general relativity for something I'm writing.  I think I get it but relativity's a bit of a brain bender.

The situation is this.  If one craft leaves the Earth and approaches light speed, then another craft leaves in the same manner, approaching the same speed and then they arrive one after the other at their destination, would they have experienced the same amount of time ie would any age gap between the two pilots remin the same?  I think they would have but confirmation would be nice.

I also need to know, but I think it's simply the twins paradox, if the first pilot turned around and came back (if the second couldn't foolow for whatever reason) would the age gap between them be significantly different (ie the one who never left would be much older or even dead) than when the first pilot left, given he reached near light speeed before turning around?  I think it would but again, best to make sure.

Cheers guys

4

General Science / Jellyfish

« on: 28/01/2006 23:12:20 »

If anyone knows, can you tell me about jellyfish - specifically about their not knowing their fronts from their behinds.

Andy

5

Physics, Astronomy & Cosmology / Wimps

« on: 28/01/2006 22:14:08 »

Okay, I'm sure someone has thought of this already, but wimps would make qualititive differences like those we currently explain with dark matter, I dunno about qualitative.

Are WIMPs easier to accelerate than normal matter?

6

Physics, Astronomy & Cosmology / Re: Is Relativity Wrong?

« on: 28/01/2006 10:10:24 »

So it's kind of like the pythagoras triangle, except it's kind of got two hypotenueses and only one regular side (or three regular sides and two hypoteneuses if you take the three spatial dimensions as three dimensions); that is the area of the square of one side (the distance) minus the area of the square of either of the other two sides (the distance light has travelled, and the interval) leaves the area of the square of the remaining side.

Interesting concept.

7

Physics, Astronomy & Cosmology / Re: What's the definition of a Dimension?

« on: 28/01/2006 09:46:16 »

The faster a charged particle moves through space, the greater the magnetic field associated with it.

Somewhat like, the faster a massive particle moves through space, the greater the gravitational field associated with it.

8

Physics, Astronomy & Cosmology / Re: What's the definition of a Dimension?

« on: 23/01/2006 20:44:16 »

Is there a deeper explanation than that?

First of all forget I said 'particle'.  I don't mean particle, I just mean a displacement from the zero value (where the plane of electromagnetism intersects with space).  If electromagnetism were a plane, and the electromagnetic charge were attracted to zero, that would explain why, as electric charge changes, a magnetic charge is induced.  Why the wave propogates.  It's spinning round the origin.

All the energy is, is the movement, ay?  the change.

On a side note (because you seem to know your stuff), A physics teacher years ago told me that electric current is actually the exchange of electrons and positrons, not just the flow of electrons as it is usually described - he said that was a simplification for the purposes of teaching.  Is that true?

9

Physics, Astronomy & Cosmology / Re: Is Relativity Wrong?

« on: 23/01/2006 02:49:13 »

the distance two events are from each other, minus the distance light has travelled in the time between these events, is invariant.  

Hmm, must sleep, but thanx for clearing up the relativities for me.

10

Physics, Astronomy & Cosmology / Re: Is Relativity Wrong?

« on: 23/01/2006 02:27:59 »

Dya see what the equatino means, yeah?  If you reduce the three spatial dimensions to a resultant distance s, you get I = s^2 - ct^2... hang on, where'd that c come from?  Musta missed that the first time round, What does that mean?

I'll get back to you

11

Physics, Astronomy & Cosmology / Re: Is Relativity Wrong?

« on: 23/01/2006 02:24:21 »

Cheers geez, that's brilliant:)  

You know, when there's something you should know and should have known a long time ago, but have only just found out?  Like a fog lifting, nice one:)

12

Physics, Astronomy & Cosmology / Re: Gravity... are we making a grave mistake?

« on: 23/01/2006 02:13:34 »

Cheers for those links Mickey, but I still think we're all gonna be laughed at by physicists of the future for this dark matter invention.

What evidence have we got that G, the 'universal' gravitational constant, is indeed universal and completely constant (for example, that's not my favourite possible explanation though)?

I'm gonna carry on reading (I got as far as the second one then branched off into MOND)

13

Physics, Astronomy & Cosmology / Re: What's the definition of a Dimension?

« on: 23/01/2006 01:00:27 »

Ah, I'm glad you're here SoulSurfer, because the question came from you making me think about angular momentum.

Stop me if I get too mad...

I'll keep it short:  Could a photon be thought of as a particle, or a pair of particles, spinning round each other and kept apart by angular momentum?  Spinning on the plane of electricity/magnetism.

I'm not sure if that would have further ramifications but it would be a way to explain wave/particle duality wouldn't it?

(Yeah!  Someone should have told Chris Waddle about that z dimension.  I can't even remember what world cup it was in but I haven't forgiven him yet:))

My physics knowledge, now that I come to excersize it after all this time, is pretty damn shakey.  I'm gonna go and look up in exactly what ways light behaves as a wave and a particle - all I can remember is the diffraction grating proving it's a wave.

What's a field again?  Again, I know what one is, more or less, but I need a precise definition.  I mean, could the intensity of any field at a given point be thought of as a displacement on a dimension?  Would there be any point?  I let myself get carried away I'm afraid:(

14

Physics, Astronomy & Cosmology / What's the definition of a Dimension?

« on: 22/01/2006 21:59:55 »

I know what the four macro ones we see are, I just don't know exactly what a dimension is.

Could we treat electrical charge as a dimension, say, or magnetic charge?

15

Physics, Astronomy & Cosmology / Re: Gravity... are we making a grave mistake?

« on: 22/01/2006 21:52:35 »

I'd be interested in reading/hearing your presentation (depending on who you're presenting it to cos it might go way over my head) because angular momentum is something that has recently started confusing me.

Why is linear movement apparently completely relative while angular movement seems to be absolute?  What's the frame of reference?  What are particles/planets/whatever rotating relative to?

Rotation, or a mismeasurement thereof, seems like another likely candidate for the reason behind dark matter/energy to me.

Do dark matter and energy seem just silly to anyone else?  It really seems to me there must be a simple explanation for the gaps between theory and observation.  It seems far more likely there's a problem with the theory rather than there's a load of matter and energy that we can't see for some reason.  


Your summary of the lifetime of our universe made me think; space must have been/must be/must be going to be much bigger than what's in it, if you see what I mean.  The cool end that you talk about is the ultimate heat death, right?  Everything is much more spread out (obviously) than it was in the beginning.  My question is, what's it growing in?  What's it growing relative to?  Because if it was hot in the very beginning when there was just energy, how can it be cool at the end, when it has all returned to energy.  Where's the extra space come from?  You say a black hole is a seperate universe from ours.  The only way a black hole gets bigger is if we drop something into it, ay?  The event horizon only expands because we've added to the mass and the internal density (presumably, insofar as we can say it exists) remains the same.

16

Physics, Astronomy & Cosmology / Re: EM and gravity

« on: 19/01/2006 01:28:45 »

OK, that sounds a bit weird because everyone knows the most fundamental particle of matter is a photon.  But maybe there're layers, or something?  Light is affected a bit, sub atomic particles a bit less. Atoms a bit less than that (per unit energy, that is).  The 'knot' in energy that makes it into matter (allows it to have mass at rest) decreses the gravitational effect.

17

Physics, Astronomy & Cosmology / Re: Gravity... are we making a grave mistake?

« on: 19/01/2006 01:14:38 »

Okay, do you concede that, though relativity talks about space-time as one thing, it also states that anything travelling at the speed of light does not experience time, it exists in an instant (from its own point of view)?

So why couldn't the inverse be true (something experiencing time but not, from its own point of view, space)?

I'm not a highly trained physicist but I got an easy A at A level and had a ****in genius teacher who took us way beyond what was necessary for the exams.  That was long ago and informal though.

I mean, gravity does not affect light's actual velocity.  It just increases the frequency of the wave. In that respect it speeds it up.  If you do the same thing to a massive body (ie increase the frequency of the wave associated with its kinetic energy), it increases its velocity.

I'm finding it hard to say what I'm trying to say.  But I'm sure if we spoke face to face you'd have a fun, if turbulent time (depends how tired I am - I'm very tired at the moment so a bit all over the place).  

It's like, 'stationary' matter can be thought of as travelling along the time axis of a space time graph.  Light travels perpendicular to it, along the space axis.  As matter accelerates, its direction (on the graph) rotates towards the direction of light.  It tends towards being energy, all that anchors it is its rest mass.  What would happen if matter turned the other way, from rest?  It becomes energy/movement rather than acquiring more.  Hmm.  So what way is light travelling on the space axis again?  Either, because time is not an issue.  It doesn't know the difference between its start and its end.

These ideas that I throw out - they may be a bit far fetched and/or undisprovable and/or they don't add anything to accepted theories.  To be honest I don't know (my maths is weak, I only got a B at A level and that was with hard work), but something I say might make a more adept physicist think along lines they wouldn't have, where they can make something useful out of it. You never know.  They do have their foundation in physics, though more advanced physics might say they're stupid.

I have to say, a lot of accepted ideas in physics are complete tripe.  Like the idea that there was 'nothing' before the big bang.  'Nothing', by definition, doesn't exist, never has, and never will.  Just as an example.


If you didn't bother reading the rest read this:


Knowledge is a barrier to understanding.  The more knowledge you have, the harder it is to understand.  A lot of graduates come out of uni chock full of knowledge but without enough understanding (I'm not including you in this).  Me and Mark, I think, understand all we know and our understanding has shot out the end of our knowledge, with momentum but no knowledge resisting it, just sparse factlets or whatever.  So we have fun stringing together what we do know.

But sorry if we're inturrupting your discussion.  I'll chill on the mad theories when I get a decent night's sleep:)

18

New Theories / Re: Unifying theory of matter solves many puzzles

« on: 19/01/2006 00:07:33 »

Soul surfer, when was the last time you made a post that didn't say "That's completely unscientific!"

19

Physics, Astronomy & Cosmology / Re: Our twin universe?

« on: 18/01/2006 23:54:48 »

Well, it seems that matter/energy does not just spring into being.  The only way it kind of does is if there is no net change in the amount of energy, ie a matter/anti-matter quantum fluctuation.  So it's at least a possibility that our universe has an opposite twin right?  Though how it affects us is hard to see.

20

Physics, Astronomy & Cosmology / Re: Our twin universe?

« on: 17/01/2006 23:33:54 »

The universe was created in a quantum fluctuation.  It hasn't grown since, it's just complexifying.  Our half was what we would call the positive particle in this quantum fluctuation, the other half was the 'negative' (though they probably put it the other way round).

That's what I think anyway.

And every quantum fluctuation in our universe is another universe being born then dieing as the pair re-anhialate(sp?) again.

Are you really mad, Mark?  Are you sure?