`ODDBALL' ICE LASTS WHEN HOT.

Byline: Peter Weiss Knight-Ridder Newspapers

Scientists probing a puzzle in astronomy couldn't believe what happened when the ice in their test apparatus was warmed to a comfortable 50 degrees or so.

Nothing.

It seemed their ice didn't melt when it was supposed to.

``I was astounded . . I thought we'd screwed something up,'' said William Durham, a Lawrence Livermore Laboratory geophysicist on a three-person team with a pair of U.S. Geological Survey scientists.

But they hadn't screwed up, it appears. Eventually, they concluded that methane gas in the apparatus had interfered with the ice's ability to melt.

``I couldn't find another explanation for their observation,'' said Jeffrey Kargel, an Arizona-based USGS planetary scientist who specializes in ices and reviewed their scientific report in the current issue of Science magazine.

What it means for science remains unclear.

``In a sense, it's a new form of water, though probably not a new crystalline form. It's the old ordinary form way out of its usual domain of existence,'' Kargel said.

Practically speaking, don't count on nonmelting ice showing up on store shelves to replace ``blue ice'' for your cooler, the discoverers said.

For one thing, it just remains solid, not cold, when warmed. Ice above the freezing point wouldn't cool any better than water at the same temperature, the researchers said.

For another, the oddball ice doesn't exist outside the pressure cylinder used in the team's experiment.

In fact, there doesn't seem to be a practical payoff at all to high-temperature ice so far.

``There may be situations in which this could be exploited, but I can't imagine what those applications could be,'' Durham said.

Still, the phenomenon is intriguing to scientists.

``Potentially, (the new finding) has much broader significance about the way substances melt,'' Kargel said.

But he noted that ``superheating,'' as the condition is known, has been seen in ice before, in 1967. But then the ice had bubbles in it and didn't survive as high a temperature.

To Durham and USGS geophysicists Laura Stern and Stephen Kirby, the peculiar ice was primarily a curious sideshow to the main aim of their research - perfecting a way of producing something called methane clathrate.

Clathrate is an icelike material itself in which water molecules form ``cages'' that have gas molecules trapped in them, in this case methane or natural gas.

It has been made before in labs, but in a powdery form that didn't enable researchers to measure important properties of the substance, such as how strong it is when squeezed.

The team's efforts, which have been funded by the National Aeronautics and Space Administration, were a success, yielding chunks of clathrate-like sticks of chalk that could be tested in compression machines.