Pressures

Something weird happens when you keep squeezing

Under extreme pressures, matter defies the rules of physics as we know it.

By Adam Cole

Physicists have a pretty good handle on how stuff behaves on the surface of the Earth. But a lot of matter in the universe exists outside this narrow band of relatively low temperatures and pressures. Inside planets and stars, the crushing force of gravity begins to overwhelm the electromagnetic and nuclear forces that keep atoms apart and maintain the shapes of molecules.

What happens next? Scientists (including a consortium of researchers at the National Science Foundation’s Center for Matter at Atomic Pressures​​) are just starting to figure that out. They use a variety of tools (including some humongous lasers) to simulate planetary cores and see what happens. A few standout findings so far:

• Water can become a hot black ice that conducts electricity
• Hydrogen gas can be compressed down into a shiny metal
• Sodium (a soft, silvery metal at atmospheric pressure) can turn transparent

What happens under extreme pressures deep within planets also influences their ability to foster life. Check out our videos about the search for Earth-like worlds beyond our solar system:

• What we found when we went looking for another Earth
• How to find a planet you can’t see
• Here’s a closer look at another giant laser at the National Ignition Facility

This material is based upon work of and presented by the Center for Matter at Atomic Pressures (CMAP), supported by the National Science Foundation under Grant No. PHY-2020249. Any opinions, findings, conclusions, or recommendations expressed in this material are those of the author(s) and do not necessarily reflect those of the National Science Foundation.