Scientists Predict How to Detect a Fourth Dimension of Space

[Kayra]

Scientists at Duke and Rutgers universities have developed a mathematical framework they say will enable astronomers to test a new five-dimensional theory of gravity that competes with Einstein's General Theory of Relativity.

 

Charles R. Keeton of Rutgers and Arlie O. Petters of Duke base their work on a recent theory called the type II Randall-Sundrum braneworld gravity model. The theory holds that the visible universe is a membrane (hence "braneworld") embedded within a larger universe, much like a strand of filmy seaweed floating in the ocean.

 

The "braneworld universe" has five dimensions -- four spatial dimensions plus time -- compared with the four dimensions -- three spatial, plus time -- laid out in the General Theory of Relativity.

 

The framework Keeton and Petters developed predicts certain cosmological effects that, if observed, should help scientists validate the braneworld theory. The observations, they said, should be possible with satellites scheduled to launch in the next few years.

 

If the braneworld theory proves to be true, "this would upset the applecart," Petters said. "It would confirm that there is a fourth dimension to space, which would create a philosophical shift in our understanding of the natural world."

 

The scientists' findings appeared May 24, 2006, in the online edition of the journal Physical Review D. Keeton is an astronomy and physics professor at Rutgers, and Petters is a mathematics and physics professor at Duke. Their research is funded by the National Science Foundation.

 

The Randall-Sundrum braneworld model -- named for its originators, physicists Lisa Randall of Harvard University and Raman Sundrum of Johns Hopkins University -- provides a mathematical description of how gravity shapes the universe that differs from the description offered by the General Theory of Relativity.

 

Keeton and Petters focused on one particular gravitational consequence of the braneworld theory that distinguishes it from Einstein's theory.

 

The braneworld theory predicts that relatively small "black holes" created in the early universe have survived to the present. The black holes, with mass similar to a tiny asteroid, would be part of the "dark matter" in the universe. As the name suggests, dark matter does not emit or reflect light, but does exert a gravitational force.

 

The General Theory of Relativity, on the other hand, predicts that such primordial black holes no longer exist, as they would have evaporated by now.

 

"When we estimated how far braneworld black holes might be from Earth, we were surprised to find that the nearest ones would lie well inside Pluto's orbit," Keeton said.

 

Petters added, "If braneworld black holes form even 1 percent of the dark matter in our part of the galaxy -- a cautious assumption -- there should be several thousand braneworld black holes in our solar system."

 

But do braneworld black holes really exist -- and therefore stand as evidence for the 5-D braneworld theory?

 

The scientists showed that it should be possible to answer this question by observing the effects that braneworld black holes would exert on electromagnetic radiation traveling to Earth from other galaxies. Any such radiation passing near a black hole will be acted upon by the object's tremendous gravitational forces -- an effect called "gravitational lensing."

 

"A good place to look for gravitational lensing by braneworld black holes is in bursts of gamma rays coming to Earth," Keeton said. These gamma-ray bursts are thought to be produced by enormous explosions throughout the universe. Such bursts from outer space were discovered inadvertently by the U.S. Air Force in the 1960s.

 

Keeton and Petters calculated that braneworld black holes would impede the gamma rays in the same way a rock in a pond obstructs passing ripples. The rock produces an "interference pattern" in its wake in which some ripple peaks are higher, some troughs are deeper, and some peaks and troughs cancel each other out. The interference pattern bears the signature of the characteristics of both the rock and the water.

 

Similarly, a braneworld black hole would produce an interference pattern in a passing burst of gamma rays as they travel to Earth, said Keeton and Petters. The scientists predicted the resulting bright and dark "fringes" in the interference pattern, which they said provides a means of inferring characteristics of braneworld black holes and, in turn, of space and time.

 

"We discovered that the signature of a fourth dimension of space appears in the interference patterns," Petters said. "This extra spatial dimension creates a contraction between the fringes compared to what you'd get in General Relativity."

 

Petters and Keeton said it should be possible to measure the predicted gamma-ray fringe patterns using the Gamma-ray Large Area Space Telescope, which is scheduled to be launched on a spacecraft in August 2007. The telescope is a joint effort between NASA, the U.S. Department of Energy, and institutions in France, Germany, Japan, Italy and Sweden.

 

The scientists said their prediction would apply to all braneworld black holes, whether in our solar system or beyond.

 

"If the braneworld theory is correct," they said, "there should be many, many more braneworld black holes throughout the universe, each carrying the signature of a fourth dimension of space."

 

Source: Duke University

[HydrogenBond]

There is an alternate explanation for what they are trying to observe. I live in Florida and it is not uncommon for little dark gray clouds to float by in front of large white clouds. The reason these little dark clouds are not reflecting white light, but look dark gray is because they are absorbing the visable light via the water molecules of the cloud. These are gray hole clouds.

 

Another explanation for no light emitted phenomena is entropy. When something expands it is endothermic. This means that it sucks in energy instead of releasing it. It will also show gravity. If one wanted to run an experiment, take a spherical canister of compressed gas. Turn off the lights and get an IR signiture. Open the valve and the canister will get very cold. One will notice the IR signiture increasing wavelength as it gets colder. This will also create an IR red shift with the canister stationary.

[arkain101]

Im not sure why you mentioned the gas in a container example.

 

Pressure in the container drops. The atoms in the can begin slowing down, or, lose energy when gas is removed because the "pressure" drops. Heat = Pressure, pressure is from the momentum of faster moving atoms.

 

Tempeture is motion of atoms. As the atoms are released, the motion inside slows down quickly, the canister atoms are suddenly is warmer or in a much higher energy state than the gas atoms inside. The energy in the tanks metal atoms is transfered to the gas. This takes away heat/energy from the metal, thus lessens the tempeture, lessenes the IR signiture frequency of the metal container.

 

Were you using this to explain that cold, black material cant be 'seen' but still has mass?

[Kayra]

Brother, I completely missed that reference HB.

Could you expand on that?

[TheBigDog]

I think there are some very bright people working on this model - but they are in the end only going to eliminate another theory from the list of possible truths. Having a few small black holes in the solar system would have been noticed by their effect on the very well plotted planetary orbits.

 

Bill

[C1ay]

The braneworld theory predicts that relatively small "black holes" created in the early universe have survived to the present. The black holes, with mass similar to a tiny asteroid, would be part of the "dark matter" in the universe. As the name suggests, dark matter does not emit or reflect light, but does exert a gravitational force.

 

For me this puts the whole theory in doubt. The term "black hole" is a term used for a collection of mass that is so great that it's gravity is strong enough to prevent even light from escaping. This requires much more mass than that of a tiny asteroid. It is theorized that even small black holes require 20 or more times the mass of our own sun.

[Panjandrum]

Black holes shrink over time, I believe. So there should be no minimum size for such a thing. These holes are also primordial, and so do not have to obey the rules of formation that apply to new black holes.

 

And, TBD, if they have the mass of a small asteroid, they will hardly cause an observable influence on the orbits of the planets.

[C1ay]

Black holes shrink over time, I believe. So there should be no minimum size for such a thing. These holes are also primordial, and so do not have to obey the rules of formation that apply to new black holes.

 

And, TBD, if they have the mass of a small asteroid, they will hardly cause an observable influence on the orbits of the planets.

If that's the case it would seem that once their mass dropped below a certain quantity their gravity would no longer be strong enough to stop light and they would become visible, no longer a black hole. A black hole is only a black hole because of it's great quantity of mass.

[Panjandrum]

No, a black hole is black because of the density of its mass, not the absolute ammount present. This would suggest to me that a black hole with the mass of an asteroid would be vanishingly small, but does not suggest that there is a minimum mass for a black hole.

[C1ay]

No, a black hole is black because of the density of its mass, not the absolute ammount present. This would suggest to me that a black hole with the mass of an asteroid would be vanishingly small, but does not suggest that there is a minimum mass for a black hole.

Oh but there is. It must have enough gravity to prevent the escape of light and there is certainly a minimum mass required for that.

[IDMclean]

A blackhole has a minimum size that it can possibly be. However it can have almost any Mass that you decide to give it. The chance of a blackhole forming from anything less than a supergiant collapsing is slim to none, but there is a chance.

 

Read up on the Schwarzschild Radius. Any mass can become a black hole, it just has to drop down to a high enough density within the Schwarzschild Radius. Hence microscopic Blackholes.

[C1ay]

Yes, there is a theoretical radius for any mass that is supposedly a black hole. There is also a minimum mass that could become dense enough under the effects of it's own gravity to become a black hole. Even a mass the size of our own sun does not have enough gravity to compress itself to such a point. Mathematical models say it is possible for external forces to have created such entities, like the braneworld theory, but there has been no observable evidence to date for which to use as a model to even propose such a hypothesis. For that reason I question the whole theory.

[Kayra]

Were the conditions in the beginning of the universe capable of forming black holes of almost any size?

[C1ay]

Was there a beginning of the universe? If there was, how do we observe the conditions at that time?