Black Ring

(Clearwisdom.net) Black holes are [thought to be] highly constrained objects with tremendous mass and gigantic gravity that will trap any object, including light that is passing by. In the 1970s, theorists [believed that they had] proved that four-dimensional black holes can only adopt a spherical shape. Until recently, most assumed that this result holds in higher dimensions as well. In the 11 March print issue of Physical Review Letter, an authoritative journal in physics, two European physicists, Emparan and Reall published their most recent research work on black holes [1, 2]. They proposed that five dimensions of space-time can harbor a rotating, donut-shaped "black ring"--the first example of a non-spherical black hole. They found that if the black ring spun fast enough, the centrifugal force would balance its gravitational self-attraction, which would hence make the ring stable. Black holes have been considered keys for checking and improving theories with higher dimensions, and the theoretical discovery of the black ring strengthens the case that these objects obey different rules when lifted from their 4D confines.

Physicists are so interested in higher dimensions because of the proposal of string theory, which attempts to unite all of nature's forces. This proposal dictates that particles are one-dimensional strings vibrating in a 10- or 11-dimensional space-time. Except for those who have supernormal ability, we are still not able to directly perceive dimensions other than the four (three of space and one of time) where we live. Many researchers consider this black ring solution in five dimensions as a remarkable discovery that opens up the possibility of a lot of new properties of black holes in higher dimensions [2].

More and more theoretical and experimental discoveries have led people to realize the possibility and necessity of the existence of higher dimensions. Thus an interesting question would be: If higher dimensions do exist, are there any living beings in the dimensions other than the 4D space-time where we live?

References:
[1]. "A Rotating Black Ring Solution in Five Dimension", Roberto Emparan and Harvey S. Reall, Phys. Rev. Lett. 88, 101101 (March 11, 2002).
[2]. "Ring Around the Singularity", JR Minkel, Physical Review Focus, March 5, 2002.

CXC/A. Hobart

(Reprinted from http://www.pureinsight.org/sci/sci/eng/newscontent.asp?ID=14503)