Astrophysicists from the Virginia Polytechnic Institute and State University and the College of New Jersey (both - USA) showed that the observations of binary systems formed by a black hole and pulsars (strongly magnetized and rapidly rotating neutron star), provide an opportunity to assess the parameters of the models, which introduces additional spatial dimension.
The existence of six or seven additional measurements, recall, is postulated in string theory, one of the most well-known theories of quantum gravity. It is considered that additional measurements do not reveal themselves because of their smallness (shrinking) and are characterized by a certain scale L, the natural expression of which would be the Planck length (~ 10-33 cm). To investigate this length scale accelerators, it is necessary to achieve energy is also comparable to the Planck (~ 1019 GeV) and approximately 1016 times greater than the possibility of the Large Hadron Collider.
An alternative to compactification considered model allows for the existence of extra dimensions is large or infinite size. This group includes the popular concept of "brane world" Randall - Sundrum model in which the universe is familiar to us is treated as a dedicated four-dimensional surface or layer called brane, in curved space-time, five-dimensional anti-de Sitter space. The fourth spatial dimension with a characteristic radius of curvature L remains invisible due to the fact that all interactions and particles of the Standard Model focused on the brane, and only gravitons (quanta of gravity) are distributed in the environment and more "volume". This approach allows us to solve a long-standing "hierarchy problem" - to explain the weakness of the gravitational interaction, which becomes apparent when compared with the other three fundamental interactions.
Model Randall - Sundrum is interesting astrophysical consequences, which include increased rate of evaporation of black holes due to Hawking radiation. Scientists have tried to use this to assess the effect of L: in 2009, the University of Arizona employee Timothy Johansen (Timothy Johannsen) found that research has long known X-ray binary XTE J1118 + 480, consisting of a black hole and evolved star, allows you to set the upper limit LL
The authors propose to study more "simple" binary systems whose elements - the black hole and neutron star - can be represented as point masses, exchange agent. Rapid evaporation of the black hole, which is described in the model of "brane world", and the natural loss of energy system (due to gravitational radiation) will produce opposite effects: in the first case, the semi-major axis of the orbit and orbital period should be increased, while the second - to decrease. For example, in a double with an orbital period equal to 7, 75 h, which consists of a black hole mass in the three sunny and about two times more light neutron star, the growth rate of the orbital period, due to weight loss, will be 0, 40 ms / year and gravitational radiation will change in 0, 12 ms / year. The value of L, has a direct impact on the intensity of weight loss is taken to be 10 microns.
The orbital period, scientists have borrowed from a double, which includes the pulsar PSR B1913 + 16 and another neutron star. Recording the emission from the pulsar, discovered in 1974, astronomers were able to calculate the rate of change of the orbital period equal to 0, 076 ± 0 000 03 ms / year.
Thus, the effect of the loss of mass black hole - 0, 40 ms / year - easily achievable differences in measurement error. If the observations of binary consisting of a black hole and neutron star, performed with similar accuracy, the physicists will be available radii L, measured in fractions of a micrometer.