Black holes may define the perfect fluid, suggests a study of black holes that only exist in a theoretical 10-dimensional space. The finding may have spawned a new universal law in physics, which puts constraints on the way fluids behave in the real world.

Dam Thanh Son from the University of Washington, US, and his colleagues used string theory to model a 10-dimensional black hole as a liquid. String theory tries to explain fundamental properties of the universe by predicting that seven more spatial dimensions exist on top of the known three. While the concept is currently unproven as a cosmological model, the tools of string theory can sometimes provide answers to real quantum problems.

That means that while the "black holes" modelled by Son are not astrophysical black holes, but mathematical objects that exist in string theory, their findings may have relevance to the real world.

The fluid has two properties that relate to the black hole's surface area: viscosity, which describes how thick the liquid is, and entropy density, which is a measure of the internal disorder. Son's team found that the ratio of these two properties is a constant which can be expressed as a mixture of fundamental constants from the quantum world. Super-cooled atoms

They suggest this constant acts as a universal lower limit for the ratio of the viscosity to entropy in real fluids. This backs an argument based on Heisenberg's famed uncertainty principle suggesting that such a limit should exist.

"That is what we hypothesise. We couldn't prove that it's the case, but we couldn't find anything that is less viscous," says Son. For example, the value of this ratio for water is 400 times greater than for black hole fluid. Even liquid helium is nine times more viscous.

Fluids that could approach the limit include super-cooled clouds of atoms, or the plasmas created in particle colliders, suggests Son.

Physicists have already drawn comparisons between the fireball produced at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory in Upton, New York, US, and string-theory black holes. "I've started taking it seriously," says Peter Steinberg from Brookhaven National Laboratory, who works with one of the teams collecting data at the RHIC.

Although RHIC have not yet measured the viscosity of their fireball, this would allow an experimental test of Son's prediction. "The final word will come from the experimentalists," Son says.

As far as the new universal law they are talking about, seems to me all the scientists here are really saying is that black holes have less viscosity (ability to move freely through a liquid) than any other object in the universe, if thought about as a liquid. For example,
Water is 60 x's more viscous than a black hole.

They are saying black holes represent the lowest viscosity fluid in the universe and therefore is a constant and tells you the lowest possible limit of viscosity.

"everyday is humbling experience when you truly realize how little we know and how insignificant we really are..."

That is how I feel when I watch an eclipse or a comet or a falling star.

Mark Twain

"Courage is resistance to fear, mastery of fear--not absence of fear."

Samuel Clemens, more commonly known as Mark Twain was born in Florida, Missouri on Nov. 30, 1835. He held many different jobs during his lifetime. Among them, a reporter, a publisher, and a riverboat pilot. In 1862 Sam began writing for many magazines and newspapers under the pen name of Mark Twain, a name taken from a riverboat term. Twain was a great writer, his three best books were Roughing It, The adventures of Tom Sawyer, and The Adventures of Huckleberry Finn. His books sold many copies. One of his books, A Tramp Abroad sold 25,000 copies. The year he was born, Halley's Comet passed over. Twain vowed that he would not die until he saw the famous comet. Then, just before he died Halley's Comet passed over. He died the next day; April 21st, 1910, at 6:30 p.m. Mark Twain stopped breathing. (He often said "I came into this world with the comet and I will go out with the comet, and true to his word, the day after Halley's Comet passed over again in 1910, he died)

Mark Twain was great even during his lifetime. He had many jobs that gave him a good education and varied experiences with many kinds of people. Something else that helped him achieve greatness in the world was that he was determined. He set goals to write his books and set many goals to write magazine articles, newspaper articles and other types of articles. A third thing that helped him achieve greatness was that he had perseverance. That quality helped him write books because he kept on trying to think of varied ways to write his stories and articles. Finally, Mark Twain learned from his experiences. He learned early on that his readers liked different writing styles. He didn't disappoint them when he wrote his humor, satire, and adventure. If his books got bad ratings, he would know not to try something different. Some of his characteristics were integrity, sense-of-humor, and initiative. Mark Twain's personality was funny, out-going, and cooperative. His humorous and insightful remarks were often quoted around the world, both then and now. Mark Twain will be remembered and quoted for a long time.

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Pudding!

Mark Twain

"Courage is resistance to fear, mastery of fear--not absence of fear."