Even so, certain places in the universe are far more crushing. The pressure at the center of Jupiter is more than a billion pounds per square inch. And then there are neutron stars, the collapsed remnants of burned-out suns, where gravity pulls atoms so closely together that the pressures are thought to reach a billion trillion times that of Jupiter’s core.

In appearance, the anvils used at Carnegie and other laboratories around the world are rather unremarkable. Designs vary, but the housing is often a pancake-shaped metal cylinder about two inches wide and less than an inch high. To exert pressure, the scientists sometimes turn the screws on the top of the cylinder, pulling the top and bottom plates closer together.

Inside, the bending of the cylinder plates presses together tips of two small diamonds, each a quarter to half a carat, typically no bigger than a quarter of an inch. On one diamond tip, a notch shaped like the caldera of a volcano has been carved to trap the material that is to be squeezed. The other tip presses down, like a stiletto heel crushing a bug. (For gases like oxygen or hydrogen, the apparatus is assembled in a box containing the gas, and some of it is trapped between the diamonds.)

The screws apply only a few pounds of force. But those translate into tremendous pressure, because the diamond tips are so small. “Pressure is just force divided by area,” Dr. Hemley said.

It is as if 100 elephants were pushing down on the point of a pencil, if one could find a pencil capable of holding all those elephants. If the diamonds have even a slight defect, they shatter — sometimes with a soft click, sometimes with a bang like a shotgun.

One of the Carnegie scientists, Timothy A. Strobel, has been using these techniques to create a new form of silicon that could more easily turn sunlight into electricity. The usual form of silicon cannot directly absorb the photons of sunlight. “The atoms in the lattice need to shake a little bit to sort of kick the electron in the right position,” Dr. Strobel said.

By squeezing a mixture of silicon and sodium, he has created a new tubelike structure. After chemically extracting the sodium, the tubes of silicon possess the desired electronic property of absorbing photons without the shaking. Dr. Strobel said the researchers were now exploring how to create the material without the high pressures so it could be used commercially in more efficient photovoltaic cells.