On Jan 5, 10:09*am, "N:dlzc D:aol T:com \(dlzc\)"
wrote:
Dear Sanny:

"Sanny" wrote in message

...

What is the mass & charge of Graviton?

Mass is expected to be very large last I heard.
Charge is zero.
In that case Say there is a Particle smaller than
an electron.

Electrons are point particles. *Nothing smaller. *But you mean
"less massive". *Neutrinos are much less massive.

And it gives out a Graviton, So Graviton must
be lighter than electron mass.

Actually I believe the graviton mass is larger than the mass of
most molecules.


What about in "string theory" how leptons and gravitons are
essentially the same string vibrating a different tune, and are
atatched or not to the "brane?"

In string theory, the basic objects are one-dimensional strings
(closed loops, or open strings-pieces with ends). The different
particles seen in experiments today are just different modes of
vibration of the string (which we see as pointlike particles because
the length of the string is too small to be resolved). Consistent
string theories also include Einstein's theory of gravity, General
Relativity, as an integral part of the formulation. This a major step
in our understanding of how to incorporate the theory of gravity into
the same framework as the other interactions. If the effect of
interactions is small, they can be described as the splitting and
joining of strings.

What happens when the strength of the interactions between individual
strings is very strong? This is not just a question of principle; we
need the answer to understand, for example, the fundamental
description of black holes. Attempts to address this question have led
to the discovery of `dualities' relating the five apparently different
perturbative theories. Other types of extended objects, known as p-
branes, play an important role in these relations, and there are also
signs that the fundamental description of string theory may be in
terms of a field theory (a theory of pointlike objects) after all.

http://maths.dur.ac.uk/~dma0sfr/cptweb/strings.htm

If string theory is a theory of gravity, then how does it compare with
Einstein's theory of gravity? What is the relationship between strings
and spacetime geometry?

Strings and gravitons

The simplest case to imagine is a single string traveling in a flat
spacetime in d dimensions, meaning that it is traveling across space
while time is ticking, so to speak. A string is a one-dimensional
object, meaning that if you want to travel along a string, you can
only go forwards or backwards in the direction of the string, there is
no sideways or up and down on a string. The string can move sideways
or up and down in spacetime, though, and as the string moves around in
spacetime, it sweeps out a surface in spacetime called the string
worldsheet, a two-dimensional surface with one dimension of space and
one dimension of time.

The string worldsheet is the key to all the physics of the string. A
string oscillates as it travels through the d-dimensional spacetime.
Those oscillations can be viewed from the two-dimensional string
worldsheet point of view as oscillations in a two-dimensional quantum
gravity theory. In order to make those quantized oscillations
consistent with quantum mechanics and special relativity, the number
of spacetime dimensions has to be restricted to 26 in the case of a
theory with only forces (bosons), and 10 dimensions if there are both
forces and matter (bosons and fermions) in the particle spectrum of
the theory.

So where does gravity come in?

If the string traveling through spacetime is a closed string, then the
spectrum of oscillations includes a particle with 2 units of spin and
zero mass, with the right type of interactions to be the graviton, the
particle that is the carrier of the gravitational force.

Where there are gravitons, then there must be gravity.

http://superstringtheory.com/blackh/blackh4.html
http://superstringtheory.com/index.html

http://en.wikipedia.org/wiki/String_theory

Dear Immortalist:

"Immortalist" wrote in message
...
On Jan 5, 10:09 am, "N:dlzc D:aol T:com \(dlzc\)"
wrote:
....
And it gives out a Graviton, So Graviton must
be lighter than electron mass.

Actually I believe the graviton mass is larger than
the mass of most molecules.

What about in "string theory" how leptons and gravitons
are essentially the same string vibrating a different tune,
and are atatched or not to the "brane?"

I don't recall that. My "string theory" text was pretty old (mid
'80s).

snip

David A. Smith

On Jan 5, 9:17 pm, "N:dlzc D:aol T:com \(dlzc\)"
wrote:
Dear Immortalist:

"Immortalist" wrote in message

...
On Jan 5, 10:09 am, "N:dlzc D:aol T:com \(dlzc\)"
wrote:
...

And it gives out a Graviton, So Graviton must
be lighter than electron mass.

Actually I believe the graviton mass is larger than
the mass of most molecules.
What about in "string theory" how leptons and gravitons
are essentially the same string vibrating a different tune,
and are atatched or not to the "brane?"

I don't recall that. My "string theory" text was pretty old (mid
'80s).

snip

David A. Smith



Reply to all of the above:

WOW! What a load of crap.

John

"malibu" wrote in message
...
| On Jan 5, 9:17 pm, "N:dlzc D:aol T:com \(dlzc\)"
| wrote:
| Dear Immortalist:
|
| "Immortalist" wrote in message
|
| ...
| On Jan 5, 10:09 am, "N:dlzc D:aol T:com \(dlzc\)"
| wrote:
| ...
|
| And it gives out a Graviton, So Graviton must
| be lighter than electron mass.
|
| Actually I believe the graviton mass is larger than
| the mass of most molecules.
| What about in "string theory" how leptons and gravitons
| are essentially the same string vibrating a different tune,
| and are atatched or not to the "brane?"
|
| I don't recall that. My "string theory" text was pretty old (mid
| '80s).
|
| snip
|
| David A. Smith
|
|
|
| Reply to all of the above:
|
| WOW! What a load of crap.
|
| John

Agreed.

Cosmik de Bris wrote:
If Gravitons have mass doesn't that imply that gravity doesn't appear as
1/r^2 force?

Yes, at least in the analogy to QFT. As I keep pointing out, we don't
yet have a complete quantum theory of gravitation, and don't really know
the properties of gravitons.


I thought the range was inversely proportional to mass.

No. Massless gauge bosons are intermediaries of a "force" that decreases
as 1/r^2. Massive gauge bosons are intermediaries of a "force" that
decreases exponentially with distance (approximately). So, for instance,
electrodynamics and gravitation have essentially infinite range, but the
weak and strong nuclear forces are negligible at atomic distances (much
less macroscopic distances).


Tom Roberts

"Tom Roberts" wrote in message
...
Cosmik de Bris wrote:
If Gravitons have mass doesn't that imply that gravity doesn't
appear as 1/r^2 force?

Yes, at least in the analogy to QFT. As I keep pointing out, we
don't yet have a complete quantum theory of gravitation, and
don't really know the properties of gravitons.

Quoting from "Superstings and the Search for The Theory of
Everything", Peat (1988)
Chapter 9 Twistor Gravity, near the back of the chapter.
"It is possible to calculate how much mass is associated with the
appearance of a single quantum of space-time, which is (very
roughly) around 10-7 g."

The "appearance of a single quantum of space-time" it take to
mean the collapse of a single graviton, and the "g" is grams.

And as I say, it is an old book...

David A. Smith

On Jan 5, 9:21*am, Sanny wrote:
Is a Black hole as big as Sun. Or it is as small as a Moon. Or just
the size of a FootBall.

Depends on the mass. And depends by what you mean by its size. The
only size we can attribute from the outsids is the event horizon. But
you don't run into anything as you pass the event horizon.

There are a few good books addressed to layfolk that would be helpful
in answering some of these basic questions. Do you need a reference,
or do you plan to do all your learning about physics from newsgroups?


Does a Black hole has a mass. And does it also have gravity. And Is it
as hot as Sun or very cool.

I heard Gravity is because a few elementary particle muon/photon
(Gravitons) are exchanged between mass. In that case how these
gravitons are able to go outside the Black hole? As I heard Black
holes even Light can not escape from it.

What are Gravitons and do they travel at speed of Light. What is the
mass & charge of Graviton? If a Mass gives out Graviton then I think
slowly it should loose Mass. Does every particle having mass gives out
Gravitons???

Bye
Sanny

Play Chess at:http://www.GetClub.com/Chess.html

"thinker" wrote in message
. ..

"Sanny" wrote in message
...
Is a Black hole as big as Sun. Or it is as small as a Moon. Or just
the size of a FootBall.

Does a Black hole has a mass. And does it also have gravity. And Is it
as hot as Sun or very cool.

I heard Gravity is because a few elementary particle muon/photon
(Gravitons) are exchanged between mass. In that case how these
gravitons are able to go outside the Black hole? As I heard Black
holes even Light can not escape from it.

What are Gravitons and do they travel at speed of Light. What is the
mass & charge of Graviton? If a Mass gives out Graviton then I think
slowly it should loose Mass. Does every particle having mass gives out
Gravitons???

Bye
Sanny

Play Chess at: http://www.GetClub.com/Chess.html

Black holes can come in different sizes depending on the conditions that
resulted in their formation (particularly its mass when it was a big
star). There is work right now to create mini-black holes in large hadron
colliders.

http://www.csmonitor.com/2003/0523/p25s02-stss.html



If you enjoy Science Fiction novels, check out 'Earth" by David Brin

Scott

thinker wrote in sci.physics.relativity:
"Sanny" wrote in message
...
Is a Black hole as big as Sun. Or it is as small as a Moon. Or just
[...]

Black holes can come in different sizes depending on the conditions that
resulted in their formation (particularly its mass when it was a big star).
There is work right now to create mini-black holes in large hadron
colliders.

http://www.csmonitor.com/2003/0523/p25s02-stss.html

Actually that article proves that the Christian Science Monitor can't
do science. LHC did *NOT* create black holes, despite the fantasizing
in the press or the mindless gushing on Google. What they did was
create a condition where only black hole equations correctly described
the supersymmetry relations. See the American Physical Society reference:

http://meetings.aps.org/Meeting/SES07/Event/73434

Now, in fairness to the "chicken Little press", there is an argument
that what looks like a black hole might actually be a black hole. Thus
several physicists think that LHC might actually be able to create
black holes some day. However, those black holes would be so unusual
and outside the constraints of Relativity, that it begs a simple
question to the press: if it quacks like a dog, why should it be a
pig? - Bottom line: no black holes now or probably ever.

--
// The TimeLord says:
// Pogo 2.0 = We have met the aliens, and they are us!

"Tom Roberts" schrieb im Newsbeitrag
...
Cosmik de Bris wrote:
If Gravitons have mass doesn't that imply that gravity doesn't appear as
1/r^2 force?

Yes, at least in the analogy to QFT. As I keep pointing out, we don't yet
have a complete quantum theory of gravitation, and don't really know the
properties of gravitons.


I' very sceptical about gravitons.
The reason is, that somehow GR is working to good. But GR is not a model of
the world, its a theory of geometry of spacetime. It does not include
particles or the other interactions.

So, if GR is 'true', then the question is not, how gravity is exchanged,
but: what does geometry mean?
Space has more properties than geometry. Its expanding, containing fields
and objects. How this is done is not known, but its known, that gravity is
nicely modelled by its geometry.

Since spacetime-geometry is only one aspect of something unknown happening
in the realm of QM, gravity should not be regarded as fundamental, maybe not
even as a force.

Thomas Heger