
DATE: Wednesday, April 30, 1997             TAG: 9704300465

SECTION: FRONT                   PAGE: A4   EDITION: FINAL 

TYPE: FOCUS 

SOURCE: BY KATHY SAWYER, THE WASHINGTON POST 

DATELINE: WILLIAMSBURG                      LENGTH:  142 lines

A FOUNTAIN OF ANTIMATTER

An orbiting observatory has detected a mysterious cloud of antimatter particles that appears to be boiling up from the center of our galaxy to form a massive fountain spewing more than 17,400 trillion miles into space.

Scientists who announced the discovery at a scientific meeting here Monday said they were amazed, perplexed and delighted by the enormous eruption apparently shooting 3,000 light-years out from the heart of Earth's home galaxy, the Milky Way.

``It is like finding a new room in the house we have lived in since childhood,'' said Charles Dermer of the Naval Research Laboratory in Washington, a researcher from one of five collaborating institutions that discovered the fountain. ``And the room is not empty. It has some engine or boiler making hot gas filled with annihilating antimatter.''

The discovery not only changes scientists' perspective on our home galaxy, but also should provide new insights to the workings of basic processes in other galaxies throughout the universe, the researchers said.

To most people, antimatter is exotic-sounding stuff frequently associated with science fiction. But the concept of antimatter flows naturally from leading theories of physics developed by Albert Einstein and others early in this century. In the form of subatomic particles, antimatter has been created in laboratories and detected in nature.

Ordinary matter is constructed of the basic atomic building blocks of protons, neutrons and electrons. Antimatter particles are exact duplicates of these except that they have opposite properties. An electron, for example, carries a negative charge while its antimatter counterpart carries an equal, opposite charge - a positive charge - and is therefore called a positron.

In theory, antimatter atoms could combine to form antimatter objects, including antimatter worlds and even antimatter people. Some theorists have speculated that ordinary matter seen in the visible universe might be balanced in some way by an unseen population of antimatter stars and galaxies.

No one has yet found a whole parallel universe, or even a single object, made of antimatter. Scientists do see antimatter particles but only when they encounter their regular matter counterparts, a union that results in a reaction called ``annihilation'' in which they are converted into radiation. When an electron and a positron meet, for example, they annihilate each other, producing pure energy in the form of two gamma-ray photons (particles of light).

This annihilation radiation, which emits 250,000 times the energy of ordinary visible light, is what researchers observed, using NASA's Compton Gamma Ray Observer - the most advanced gamma ray hunter ever deployed.

The researchers were astounded to find evidence of a cloud of antimatter particles towering above the plane of the galaxy, a neighborhood believed to be so empty of material that some particularly violent or unusual mechanism - a smoking ``positron gun'' - will be required to explain it, they said.

``The origin of this new and unexpected source of antimatter is a mystery,'' said William R. Purcell, of Northwestern University.

The two most likely sources are antimatter factories at the verge of black holes, such as one called the Great Annihilator, or ``the funeral pyre of a thousand star deaths'' occurring in waves of titanic explosions, or both in combination.

Calling the fountain ``a wondrous discovery,'' Dermer said the question is how does it get up so high? ``In my opinion, furious activity is boiling hot clouds of gas from our galaxy's center into its halo. . . . It's a cauldron of violence. It's the inner city of our galaxy.''

Another intriguing aspect is the assymetry of the fountain, which is spewing toward the ``north'' but not the ``south'' of the galactic center, said James D. Kurfess, head of the Naval Research Laboratory's Gamma and Cosmic Ray Astrophysics Branch. Kurfess and others speculated that a low-pressure area had developed in a process that resembled lifting the lid off a pot of boiling water. This allowed the fountain, or chimney, effect to develop in just one direction.

Earth's solar system inhabits the outskirts of the Milky Way about 25,000 light years from its violent core, which is located in the direction of the constellation Sagitarius and shrouded from the view of optical telescopes by intervening gas and dust. Only by observing in other wavelengths of light - such as infrared, X-ray and gamma ray - can observers penetrate the fog.

What they seem to reveal, at least by some interpretations, Dermer said, is something like this: ``Exploding supernovae stars and short-lived overweight stars expelling howling winds of radioactive debris and thermonuclear detonations on white dwarf novae (a type of stellar eruption) all make the space between the stars a hot, dirty gamma ray-active environment.''

Many astronomers agree that a monstrous black hole with the mass of a million suns lurks at the dynamic center of our galaxy, but it is strangely quiet, as though between ``feedings.'' There are several other black hole candidates in the galaxy, such as the Great Annihilator, which, though it weighs only 10 to 100 times the mass of the sun, produces X-rays and jets visible in radio wavelengths and possibly made of antimatter.

If the fountain is not manufactured by either a black hole or the fallout from the explosive death throes of many massive young stars as they are pulled collectively toward a black hole, Kurfess said, then it might even be the cooling remnant of a fireball triggered near the galaxy's core in the collision of two incredibly dense neutron stars perhaps a million years ago, which would have released in an instant the amount of energy the sun will produce in all its 10-billion-year lifetime.

If so, the finding could shed light on the separate mystery of the gamma ray bursts found by the Compton observatory to be firing at Earth from all directions of the sky at a rate of about one a day. Some scientists believe those bursts are caused by the collisions of neutron stars.

Antimatter has been a continuing source of puzzlement for theoretical physicists and astronomers. According to theories about how the universe was created, almost equal amounts of antimatter and matter were created in the initial Big Bang. Ordinary particles apparently slightly outnumbered their antimatter counterparts and survived the early period just after the Big Bang to evolve into the universe we see today.

If the primordial stew had been slightly different, scientists note, the universe might be empty of stars, planets and people.

Scientists created the first antimatter particle in a particle accelerator in 1933, but they did not find antimatter existing naturally in the universe until the 1970s, when Rice University scientists showed the gamma ray glow of annihilation radiation coming from the central bulge and along the disk of our galaxy. ILLUSTRATION: GRAPHIC

[For a copy of the graphic, see microfilm for this date.]

SOURCE: Naval Research Laboratory

Washington Post

The Milky Way

SCIENCE BRIEFING

What is the Milky Way? The galaxy we live in. It looks something

like a fried egg with pinwheel spirals. Earth lies in one of these

spirals.

What are antimatter particles? Duplicates of the atomic building

blocks of ordinary matter - protons, neutrons and electrons - but

with opposite properties. An electron, for example, carries a

negative charge while its antimatter counterpart carries an equal,