Tuesday, February 21, 2017

As hard as ... hydrogen?

At sufficiently high pressure, hydrogen liquefies starting at about 33 Kelvin.(*) That's cold. At about 14 Kelvin and yet more pressure, hydrogen will become a solid. And, it has been theorized since 1935, under enough pressure solid hydrogen can take metallic form.

(*) For mysterious reasons, absolute temperatures are shown in units of Kelvin, and not (as every other temperature scale would suggest) degrees Kelvin.

Not quite this easy
How much pressure? In round numbers, call it five million standard atmospheres. The amazing thing is, Harvard scientists reported last month that they had formed metallic hydrogen in the lab. "U.S. scientists create metallic hydrogen, a possible superconductor, ending quest." That's seriously cool. And high pressure.

Should you care? That's unclear. In the "no" column, and as Scientific American reports, skepticism abounds. "Doubts Cloud Claims of Metallic Hydrogen." But if the result is confirmed, then what?

For one, we may be able to study material believed only to be found naturally (in this solar system, anyway) at the heart of Jupiter. For another, we might have a room-temperature superconductor.

Me? I'd be leery of using -- hell, of being anywhere near -- something containing metallic hydrogen. Why? Think for a moment about the energy stored in metallic hydrogen in the course of applying all that pressure. What happens if/when something causes all that potential energy to become ... kinetic?

So: metallic hydrogen (again, I caveat: if it really exists and can be artificially produced) should beat the heck out of, say, kerosene or old-fashioned liquid hydrogen. As in "Lab-Made 'Metallic Hydrogen' Could Revolutionize Rocket Fuel."

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