Black Hole Dynamos Spawn Monster Energy Fields

June 3, 2002

ALBUQUERQUE, New Mexico (Reuters) -- Cosmic dynamos in black holes could be the most efficient power plants in the universe, spawning magnetic energy fields so big they push past galaxy borders and into intergalactic space, scientists said Monday.

These monster magnetic fields have been known to astronomers for decades, and the link between them and black holes has also been theorized, but now researchers have created a picture of the energy fields and measured just how huge they are.

Astronomers at the Los Alamos National Laboratory did this by interpreting radio waves emitted by such fields, revealing an image that looks like a pair of red wings with white circles at their tips.

The red wings are the magnetic fields and between them lies the galaxy, with a black hole believed to be at its center. The fields span as much as 10 million light-years, several times the size of the galaxy at their core. A light-year is about 6 trillion miles, the distance that light travels in a year.

Black holes have never been absolutely confirmed, but evidence has steadily mounted and most astronomers accept that they exist.

They are matter-sucking drains in space that inhabit most galaxies, including the Milky Way that contains Earth, and they have gravitational pull so strong that nothing, not even light, can escape.

Into intergalactic space

However, the furious activity that occurs around the rim of the black hole, before matter falls into it, appears to generate the magnetic fields, the Los Alamos scientists said at a meeting of the American Astronomical Society, in Albuquerque.

The energy contained in these huge magnetic fields is comparable to that released into space as light, X-rays and gamma rays, which means that the black hole's power generator is highly efficient, according to astronomer Philipp Kronberg.

There is an upper limit to how much energy each black hole can put out, Kronberg said at a news conference, and there is "an uncomfortably small gap between the size of the fuel reservoir and the actual energy that has to be put out.

"What this tells us is that the energy has to be put out very efficiently," Kronberg said.

He said systems like the one in the image may tend to spread out into intergalactic space. "And if they have, it means that there's a substantial fraction of energy in intergalactic space."

This energy might have been generated by a very dense, super-small but super-massive black hole, Kronberg said.

Black holes can theoretically be billions of times the Sun's mass, but scientists have also postulated that tiny ones also exist.

In another finding reported at the meeting, scientists from the National Optical Astronomy Observatory have detected two black holes in Earth's celestial neighborhood that each have a mass of just a handful of Suns.

One has a suspected mass of just 5.25 solar masses and the other has 4.25 solar masses, the scientists said in a statement.

Black holes are believed to be the end result of a very massive star's life and the progenitor stars of these two black holes are thought to have had masses greater than 25 times the Sun's.

http://www.cnn.com/2002/TECH/space/06/03/black.hole.dynamos.reut/index.html