In 2008, Miguel Ramos read in the newspaper that 110-million-year-old amber bearing pristine Mesozoic insects had been discovered a few hours’ drive from Madrid, where he lived. A physicist who specializes in glass, Ramos had wanted for years to get his hands on ancient amber. He contacted the paleontologists working at the site, who invited him to visit.
“They provided me with the clear samples that are not good for them,” he said. “They have no interesting insects or whatever … but they are perfect for me.”
Ramos spent the next several years intermittently working on measurements of the ancient glass. He hoped that the fossilized tree resin, after aging for so long, might approach a hypothetical form of matter known as ideal glass.
For decades, physicists have dreamed of this perfect amorphous solid. They desire ideal glass not so much for its own sake (though it would have unique, useful properties) but because its existence would solve a deep mystery. It’s the mystery posed by every window and mirror, every piece of plastic and hard candy, and even the cytoplasm that fills every cell. All of these materials are technically glass, for glass is anything that’s solid and rigid but made of disordered molecules like those in a liquid. Glass is a liquid in suspended animation, a liquid whose molecules curiously cannot flow. Ideal glass, if it exists, would tell us why.
Inconveniently, ideal glass would take so long to form that it may not have done so in all of cosmic history. Physicists can only seek indirect evidence that, given unlimited time, it would. Ramos, an experimental physicist at the Autonomous University of Madrid, hoped that after 110 million years of aging, the Spanish amber might have started to show glimmers of perfection. If so, he would know what the molecules in ordinary glass are really doing when they appear to do nothing.
Ramos’s amber measurements are part of a surge of interest in ideal glass. In the past few years, new methods of making glass and simulating it on computers have led to unexpected progress. Major clues have emerged about the nature of ideal glass and its connection to ordinary glass. “These studies provide renewed support for the hypothesis of the existence of an ideal-glass state,” said Ludovic Berthier, a physicist at the University of Montpellier who was centrally involved in the recent computer simulations.
But the emerging picture of ideal glass only makes sense if we set aside one piece of evidence.
“Indeed,” Berthier said, “the amber work stands out as difficult to rationalize.”
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