DISCOVERY OF UNIVERSAL UP, DOWN CHALLENGES CONCEPTS OF SPACE, LIGHT.

Byline: John Noble Wilford The New York Times

Measurements by scientists have suggested for the first time that the universe has an ``up'' and a ``down.''

The observation, if correct, would be one of the most surprising and fundamental new insights about the universe to emerge in recent years. The notion that space is uniform, that it is the same in all directions, with no north and south or up and down, is a major tenet of modern cosmology, backed by Einstein's theory of relativity.

The findings could force scientists to reconsider aspects of Einstein's theory, rethink some ideas about the birth of the universe and the possible existence of other universes. They also raise questions about the speed of light, especially whether it may not be always precisely the same.

In an analysis of radio waves from 160 distant galaxies, physicists at the University of Rochester and the University of Kansas made the startling discovery that the radiations rotate as they move through space, in a subtle corkscrew pattern unlike anything observed before.

A complete turn of the corkscrew appeared to occur every 1 billion miles the radio waves travel. These effects are in addition to what is known as the Faraday effect, a polarization of light caused by intergalactic magnetic fields.

Even more surprisingly, the magnitude of these newly observed rotations appear to depend on the angle at which the radio waves move in relation to a kind of axis of orientation running through space. The more parallel the direction of travel of the wave is with the axis, the greater the rotation. The reason for this remains unknown.

This axis of orientation is not a physical entity, but rather defines a direction of space that somehow determines how light travels through the universe. As observed from Earth, the discoverers said, the axis runs one way toward the constellation Sextans and the other toward the constellation Aquila. Which way is up and which way down, whether toward Sextans or Aquila, would be a matter of arbitrary choice.

The discovery was made by Dr. Borge Nodland of Rochester and Dr. John Ralston of Kansas, using radio-wave observations made by different astronomers around the world. In a report to be published on Monday in Physical Review Letters, the two physicists concluded on a note of excitement tempered with caution.

``Barring hidden systematic bias in the data,'' they wrote, the behavior of electromagnetic radiation propagating over vast distances ``indicates a new cosmological effect.''

In an announcement by the University of Rochester on Thursday, Nodland said: ``The big news is that perhaps not all space is equal, for as far back as we can peer in time. This work defies the notion that there is no up or down in space.''

Ralston said, ``Our observational data suggest that there is a mysterious axis, a kind of cosmological north star that orients the universe.''

Few other physicists and cosmologists have had a chance to read the journal report, but they agreed that the research must be tested thoroughly before the conclusions can be accepted.

``It would be a really profound change in physics, if it is true,'' said Dr. P. James E. Peebles, a Princeton University astrophysicist.

Dr. Stephen Maran, an astronomer at the Goddard Space Flight Center in Greenbelt, Md., said: ``Anytime you find a new effect globally in the sky, the crucial issue is always whether you have correctly taken account of systematic errors in the observations. And any result of this potential magnitude is going to be viewed with considerable skepticism until new experiments can be done to verify it.''

In their report, Nodland and Ralston constructed a mathematical theory that could explain the observations. The data indicate that light actually travels through space at two slightly different speeds. Such a mismatch in speeds would cause the polarization plane to rotate in a certain familiar manner. It is the way physics students see when they pass light through corn syrup and look at the light with polarizing filters.

The physicists say the axis of orientation they have inferred would appear to be along different lines in different parts of the universe, but they would be parallel to the one observed from Earth.

Because the findings run counter to the idea that all space is uniform and that the speed of light in a vacuum is always the same, the implications of the research could be enormous. For example, scientists might have to reconsider the concept that the big bang, the theorized moment of cosmic origin, was completely symmetric.

``Perhaps it was not a perfect big bang, but a big bang with a twist to space and time,'' Ralston said. ``Such a twist would be seen today as a ripple of nonuniformity, perhaps as the axis represents.''