Scientists find a practical test for string theory. (Phys.org) —Scientists at Towson University in Towson, Maryland, have identified a practical, yet overlooked, test of string theory based on the motions of planets, moons and asteroids, reminiscent of Galileo's famed test of gravity by dropping balls from the Tower of Pisa.
String theory is infamous as an eloquent theoretical framework to understand all forces in the universe —- a so-called "theory of everything" —- that can't be tested with current instrumentation because the energy level and size scale to see the effects of string theory are too extreme. Yet inspired by Galileo Galilei and Isaac Newton, Towson University scientists say that precise measurements of the positions of solar-system bodies could reveal very slight discrepancies in what is predicted by the theory of general relativity and the equivalence principle, or establish new upper limits for measuring the effects of string theory.
The same test could be used for string theory, Overduin said. Imagining 10 Dimensions - the Movie. Black Holes May Have 'Hair' Black holes may not be bald after all.
In a challenge to traditional models of the universe's gravitational monsters, new research suggests black holes could be quite "hairy," with more tangled features than previously believed. The gravitational attraction of black holes is so strong that even light cannot escape their pull, making these super-dense objects invisible to outside observers and almost indistinguishable from one another. "The accepted picture is that black holes are very simple objects that can be fully characterized by only 3 quantities: their mass, their angular momentum (how fast they spin) and their electric charge," Thomas Sotiriou, a physicist at the International School for Advanced Studies of Trieste, told SPACE.com in an email.
The electric charge, however, is usually negligibly small, and researchers typically throw it out when describing a black hole. "These are theories different than Einstein's theory, general relativity," Sotiriou wrote in an email. Do black holes have hair? A new hypothesis on the nature of these celestial bodies. Black holes may be less simple and "clean" than how the most authoritative theoretical model describes them.
This is what a group of researchers based at the International School of Advanced Studies, Trieste, and IST, Lisbon, claims in a new article appeared in Physical Review Letters. According to the scientists' calculations, these celestial bodies may actually have "hair". A black hole. A simple and clear concept, at least according to the hypothesis by Roy Kerr, who in 1963 proposed a "clean" black hole model, which is the current theoretical paradigm.
From theory to reality things may be quite different. According to the traditional model, black holes are defined by only two quantities: mass and angular momentum (a black hole rotation velocity). According to Sotiriou, things may not have occurred this way. Explore further: Capturing black hole spin could further understanding of galaxy growth. String Theory (Dimentions) Brian Greene: Making sense of string theory. Quantum Diaries. What’s the deal with string theory?
Why do people claim string theory is nonsense? Can we predict anything with it? As a theorist with too many experimental friends, these questions are thrown at me all the time. So today answering these will be my challenge. Dislaimer: In the following I might have wiped too many ‘details’ under the doormat in order to keep everything readable. Basically string theory says that the tiniest bits of matter are in fact little strings, in contrast to for example the Standard Model, where every particle is considered to be a point.
Anyway, we are now with a 10-dimensional theory. The answer is that we think that these extra dimensions are ‘compactified’. Now, for our string theory, we need to compactify six dimensions. Now the funny thing is, that for every different way you compactify the extra dimensions, the laws of Physics, as in the coupling constants, interactions and even the particle content in our four known dimensions will be different.