October 2009 - Solid, liquid, gas. These primary states of matter are taught early in a child's education. And if the teacher asked in what state of matter aluminum is normally found, the answer would be solid. After all, it's a metal known for its strength and lightweight versatility.
But the answer to that question isn't so cut and dry anymore. Scientists in Hamburg, Germany, have recently created a new state of matter using aluminum foil and a gargantuan amount of X-ray power. This isn't plasma, the fourth state of matter, which is a superheated and partially ionized gas found in stars. This new state of matter is called transparent aluminum.
Seeing it through
If you've watched "Star Trek," you may have heard of transparent aluminum before, as the concept has been tossed around by science fiction writers. However, fiction became reality when scientists inundated a thin piece of aluminum foil with an X-ray laser capable of generating 10 million gigawatts of power per square centimeter. The high-powered synchrotron radiation generator, called the Flash laser, focused on a spot with a diameter far thinner than that of a human hair, turning it transparent for 40 femtoseconds. (A femtosecond is one-quadrillionith of a second.)
As the New Scientist explains, solid aluminum has a bevy of free electrons roaming between ions. Usually in such solid metals, if an electron is kicked out of an ion, a free-roaming electron will replace it instantaneously. However, the Flash laser is able to knock an electron out of every atom in its path before replacements arrive, causing a different electron configuration, and, thus, making the material transparent to X-rays.
Although the material used in the experiment exploded virtually instantaneously, in that sliver of a second, a new state of extremely hot, solid matter was created, one the scientists theorize could be at the core of giant planets like Jupiter.
"Transparent aluminum is just the start," said professor Justin Wark of Oxford University's Department of Physics, Oxford, England, in a news release. "The physical properties of the matter we are creating are relevant to the conditions inside large planets, and we also hope that by studying it, we can gain a greater understanding of what is going on during the creation of 'miniature stars' created by high-power laser implosions, which may one day allow the power of nuclear fusion to be harnessed here on Earth."
Fusion power, of course, is the goal of such experiments, as the theoretical power source would be cheap and plentiful. MM