The Physics of Glass Just Got Blurry

One popular scientific idea is that matter turns from liquid to solid at a discrete point, but a study in tomorrow's issue of the journal Physical Review Letters suggests that the shift is continuous.

This realization could frustrate researchers in the field, as it makes transition-physics calculations all the more difficult. While the finding is mainly useful for future physics research, it might help scientists better understand the structure of the universe and could also lead to the development of golf clubs that pack a greater wallop.

Solid or liquid?

By nature, glassy materials are tricky to define. They have the disordered configuration of a liquid, but at cool temperatures they're so viscous and the molecules flow so slowly that they exhibit the brittle characteristics of a solid.

Physicists have spent considerable time attempting to identify what causes glassy matter's dramatic change of state. Some researchers proposed the ideal glass transition theory as the point during the transition when the material is cooling and the molecules have no option but to snap from a disordered liquid configuration to a highly-ordered solid one.

But when Salvatore Torquato of Princeton University and his colleagues performed random computer simulations of the transition, there seemed to be no well-defined point when all materials would make the transition.

"What we're saying is you could have this continuous change from most disordered to most ordered, and there are an infinite number of possible transition phases between these points," Torquato told LiveScience. "It puts another nail in the coffin for [the ideal transition] theory."

Unraveling the universe?

The finding will dismay some physicists. The previous and ideal explanation fit nicely within the already well-defined laws of thermodynamics—the description of the movement of energy in a system—and following these normal laws makes calculations simpler.

Although Torquato believes the new work will be most beneficial at a fundamental level for studying physics, it could help other scientists work out the structure of the early universe, which some believe existed in a somewhat amorphous, disordered state.

Or it might lead to the development of better industrial plastic materials and other useful polymers.

"Glasses can be formed from any substance, and the way their molecules interact places them somewhere at the border between solids and liquids, giving them some properties that manufacturers can exploit," Torquato said. "Golf club heads made of metallic glasses, for example, can make golf balls fly farther."