Science a GoGo's Home Page Forums General Discussion General Science Discussion Forum Edge of the Universe

And it was really Cambridge Ontario Canada ... not Cambridge England.

Rob: Actually, when I spoke to the lecturer, I didn't use the rubber band example, What I really I said to him was; "But then you could divide the strings into smaller strings." Secondly, I must point out that he didn't actually 'agree' with me, he just said "I suppose so."

Obviously he's not a string physicist then.

Perhaps a rubber- band physicist. ;-)

can you find a number that can't be sub divided?
and zero is not a number, it's an abscence of numbers. point proved (hopefully).

Probably absolutely nothing-a void

a void is what zero is.

how can anything that exists have an abscence of mass?

It can't. It just can't.

Except, of course, for photons.

Case closed.

You need to distinguish between mass and rest mass. Anything can exist without rest mass. Perhaps everything fundamental actually does. The problem here is that you are assuming that you know what mass is ... an that is something I doubt so lets examine what it is.

Mass is the resistance of an object to accelleration: Nothing more. Put your hand into the air and wave it about. Now do the same thing in a bucket of water. Feel the resistance to accelleration? Did your arm experience a corresponding increase in mass? I hope not.

ok then, just pretend that all the times I said mass, I was actually saying matter. Therefore, nothing that has no matter can exist.

Depending on how one defines "matter" you may or may not be correct.

Are photons matter?
Are phonons matter?

One of them definitely is not. The other arguably not.

Grrr, all these technicalities are annoying. Ok, look, MY own personal definition for matter which is the one I am going to be using from now on is this; Matter: something with weight.
Now you could say a photon has no weight, but look at it this way. A feather would appear weightless on a scale designed to weigh elephants.
YET AGAIN, I go back to my original point; nothing can be said to exist unless it has WEIGHT.

Your personal defintion of anything is irrelevant.

If you wish to communicate with this planet's other inhabitants you need to use a common language. And guess what ... in physics ... it isn't whatever you decide it is.

I did not say a photon has no weight though that is true as weight does not exist. The question is mass and the question specifically is with respect to rest mass.

Weight is not a concept with any meaning thus you don't have a point to return to. You really should either stop posting on a science site or learn the value of staying awake in school.

I don't go to school.
Let's go back to numbers YET AGAIN. Divide infinity by two infinity times but you'll never get to zero. That's the point I've been trying to make since I GOT HERE.

Rob wrote:
"I don't go to school."

Obviously!

Rob wrote:
"YET AGAIN, I go back to my original point; nothing can be said to exist unless it has WEIGHT."

then Rob wrote:
"YET AGAIN. Divide infinity by two infinity times but you'll never get to zero. That's the point I've been trying to make since I GOT HERE."

Compare the two paragraphs above? Go back to school and this time concentrate on getting an education. Alternatively learn to ask "Do you want fries with that?"

hehehe

Rob, let me ask you something. Consider the polynomial fraction (x-1)/[(x-2)(x-3)]. What is the value of this fraction as x becomes infinitely large (in the dedicated lingo as x tends/goes to infinity)?

Pasti, hold on one second

DA Morgan,
?Obviously!?
Yawn, how predictable.

"Compare the two paragraphs above? Go back to school and this time concentrate on getting an education."
Compare the two paragraphs above? I don't see your point.

Forget infinity; divide the number 1 by 2 forever and you still wont reach zero, EVER! Do you need an education to realise that?

Wow Rob ... you've proven you have a junior high school level education if one assumes a C average.

No doubt Pasti, working on his degree is physics, is marveling at your grasp of the elementary. But you didn't respond to the question he asked: Why?

"Forget infinity; divide the number 1 by 2 forever and you still wont reach zero, EVER! Do you need an education to realise that?"

Slight miscommunication.

It doesn't have to reach. It "tends to" zero, in the jargon. That's why in math, we use the limit:

lim (x-c)/[(x-a)(x-b)]
n->inf

What is it "in the limit," regardless of whether that limit is ever reached. As n "increases without bound," the value of the function approaches zero. (This should be intuitive, but you can also use L'Hopital.)

OTOH, there is a semantic gap in that mathematics doesn't necessarily have to correspond to our physical reality - and vice versa.

I disagree with your assertion that nothing exists unless it has weight. I think that's far too specific a definition. A slightly better one might be that nothing exists unless it is capable of producing "some (putatively) observable effect on something else."

Yours is a dangerous assertion in that there's no justification for it. We might as well declare that nothing can be said to exist unless it's made of peanut butter.

The argument about not having an instrument fine enough to measure (either weight or mass) of a photon is also flawed (not just on lack of evidence, but of even being scientifically legitimate) unless you can propose an experiment that might prove you're wrong, if you are wrong.