Science News Review

What Does It Mean for a Singularity to be Naked?

Mar 2 at 8:08pm by Aileen

Almost everyone who is interested enough to follow scientific developments is familiar with the good old “Black Hole” in space. This is what happens when massive stars collapse in on themselves and there’s nothing to stop it. Eventually all the mass gets crushed to infinite (or near infinite) density, creating a “Singularity.” This tiny point in spacetime exerts all the gravity of all the mass that became part of it, so their effects can be observed on other stars and matter near them.*

[* High energy physicists have suggested that singularities can come in much smaller 'mini' and 'micro' size, and are hoping to produce one at CERN if they ever get the Large Hadron Collider going.]

These black holes are said to be hidden behind an event horizon, where matter and energy being sucked in toward the singularity exceeds the speed of light. Beyond that boundary of spacetime, nothing within can ever get out again. Roger Penrose came up with the Cosmic Censorship hypothesis back in the ’70s when he and Stephen Hawking were formalizing the solutions to Einstein’s equations that predicted the existence of black holes. It seemed ‘indecent’ to Penrose that a singularity might ever exist that was not shielded from outside view by an event horizon, and that view predominated research for decades despite whispers here and there that naked singularities could indeed exist.

The axiom of cosmic censorship is that “Nature abhors a naked singularity.” Penrose complains that an indecent singularity would do some very strange things to time, making mincemeat of our notions of cause and effect. Three decades later theorists are not so sure. It was reported back in September of 2007 that…

Some Black Holes May Not Be Black – researchers from Duke University and Cambridge published in the journal Physical Review D their solutions to the equations of general relativity which predict the existence of naked singularities. Worse, they came up with some ways of testing the gravitational lensing and radiation emissions expected from such a phenomenon, that could soon be observed with current and new technology.

In the February issue of Scientific American, theorist Pankaj Joshi writes an informative 5 pages of explanation in the article -

Do Naked Singularities Break the Rules of Physics?

“If naked singularities exist, the implications would be enormous and would touch on nearly every aspect of astrophysics and fundamental physics. The lack of horizons could mean that mysterious processes occurring near the singularities would impinge on the outside world. Naked singularities might account for unexplained high-energy phenomena that astronomers have seen, and they might offer a laboratory to explore the fabric of spacetime on its finest scales.”

Some astrophysicists are probably dreading the implications, but it looks like an increasing number of others are quite excited about it as a way forward in their quest to understand the true nature of space and time and the behaviors of all things existing here. Joshi concludes his article with this enthusiasm…

“Either proving or disproving cosmic censorship would create a mini explosion of its own within physics, because naked singularities touch on so many deep aspects of current theories. What comes out unambiguously from the theoretical work so far is that censorship does not hold in an unqualified form, as it is sometimes taken to be. Singularities are clothed only if the conditions are suitable. The question remains whether these conditions could ever arise in nature. If they can, then physicists will surely come to love what they once feared.”

Links:

Wiki: Naked singularity
Do Naked Singularities Break the Rules of Physics?
Some Black Holes May Not Be Black