# Anti geometry

1. Mar 15, 2006

### wolram

I think it is true to say that every thing in the universe must ballance in some way, apart from matter over comming anti matter, by some un explained process, so if the universe can be explained by some metric, is there an anti metric ?

2. Mar 20, 2006

### louis arthur

me too

I'm not sure, but I'm new. I was wondering about the speed of light, and how traveling faster would mean catching up to and over taking old light. If I travel faster than light sending me back in time, which gives me negative time, then doesn't that mess up Speed = Distance/Time? I would have a positive speed, a positive distance and a negative time. Or maybe I have a negative distance, which is opposite to my senses which tell me that any distance traveled is positive. Is this anti-distance? And wouldn't a negative distance be indicative of a negative goemetry? I sure would like to have someone to talk with about this, and pass these thoughts on to someone who can do something with them.

louis arthur

3. Mar 22, 2006

### hossi

anti

since the metric describes gravity, I would think what you are looking for is anti-gravity rather than anti-distances (which I admittedly can't make any sense of).

4. Mar 22, 2006

### louis arthur

i read that gravity and acceleration are interchangeable, so that must mean that anitgravity and antiacceleration are interchangeable. if i could antiaccelerate, what kind of motion would i travel in?

5. Mar 22, 2006

### hossi

6. Mar 23, 2006

### wolram

Hossi, would this mean that anti matter collects in null gravitating areas (Lagrange points) of
space ?

If there is anti-gravitating matter, why don't we see it?

First, recall that both types of matter repel. Thus, if there is anti-gravitating matter, it would not stay here. It would move away as far as possible. Then the question reduces to why we do not produce anti-gravitating matter in accelerators or in ultra-high energetic cosmic rays.

Last edited: Mar 23, 2006
7. Mar 23, 2006

### MathematicalPhysicist

the question is what do you equate as anti gravity?
for example we can look at a macroscopic body which two force are acting upon him from different direction (both horizontal) one is gravity and the other let's say coulomb force of electricity given by similar equations. then you can say that that electricity is the anti force to gravity.

any way, this is semantics.

another good inquiry is:
we have 4 known forces: the weak force, strong force, electromagentism, gravity and also the corresponding forces of weak-electromagenitsm,strong-electro.
but as far as i know they don't have a geometrical manifestation as does gravity have in gr. parhaps if there's antigravity force or opposite force to gravity we should look at gravity acting upon anti matter (although besides some properties it's almost identical to matter), but as far as i know there isn't any macroscopic anti matter so it's quite hard to check it.

8. Mar 23, 2006

Staff Emeritus
The expansion of spacetime, aka the cosomological constant, might be thought of as anti-gravity. There are solutions of Einstein's field equations which employ spacetime expansion to generate a constant acceleration (modifications of Alcubierre's "spacewarp"). These violate a basic desideratum called the weak energy condition and are generally considered unphysical.

9. Mar 23, 2006

### MathematicalPhysicist

selfadjoint, gravity is supposed to be a force acting upon masses or bodies (they are the same) so as is see it, anti gravity or repulsive force to gravity should act on masses as well.
is gravity a force which is a property of space or of the (masses) bodies which occupy the space?

if it's a property of mass, then as i reackon if the expansion of the universe is because of matter then doesn't it imply that gravity acts both way, also repulsive and attractive, it's quite contradictory is it not?

10. Mar 23, 2006

### hossi

There are several proposals to actually measure the grav. force on anti-matter, anti-matter meaning anti wrt the gauge charge.

See e.g.

http://xxx.lanl.gov/abs/gr-qc/0602041
Testing existence of antigravity
Authors: Dragan Slavkov Hajdukovic

However, I don't think that e.g. a positron will behave differently concerning the graviational interaction than an electron does. I think, this would probably also spoil up some loop-corrections or so (sorry, don't have a proper reference.) In contrast to this what I proposed is a second sector of the standard model, which is identical to the one we already have, except for its graviational interaction. Its kind of confusing with the terminology, but then one indeed has anti-graviating-anti-matter and anti-matter.

Thanks so much! :rofl: It's so unphysical it could solve some singularity problems.

Best,

S.

11. Mar 23, 2006

### wolram

I am sure i have read about a particle that switches from being matter to
antimatter, at a frequency of fempto seconds, one part was a strange quark
i think, cuss my memory, but if the oscillations of this particle had a very
slight variable offset one way or the other, could it not explain accelerated
expantion ?

12. Mar 23, 2006

### hossi

No. Why would it? Its not as complicated as you think. Take electromagnetism (spin 1 field) and replace 'unlike charges attract, like charges repel' with 'like charges attract, unlike charges repel'. The rest are details

B.

13. Mar 23, 2006

### wolram

Dohh, i am sure my brain is made of week old porridge.

14. Mar 23, 2006

### hossi

Thats how I feel every morning :rofl: