I was watching Star Trek: The Next Generation the other night and started thinking about plasma. Funny how these things happen. The show mentions it on a regular basis: Plasma conduits, plasma power converters, and the like. You know the drill.

This particular episode dealt with a planet who was ironically trying to force a greenhouse effect after their planet had been thrown into a near ice age of sorts. The plan implemented by the Enterprise's crew backfired, causing massive earthquakes, volcanic eruptions and subsequent volcanic ash, the latter of which was going to choke out the remaining sunlight from getting through. The resolution (spoiler alert for those of you who watch the show but haven't seen this particular episode yet) was to convert the volcanic ash to plasma, suck it back into the Enterprise, then fire it off into outer space. I may be a little fuzzy on some of the details, but there you go.

So I got to thinking about plasma. What is it really? When was it first discovered, and how? Oz kind of hit the nail on the head when he suggested it was first discovered as we entered into the Nuclear Age, but after a little research I guess technically it was discovered by prehistoric man. They knew it was there, they just didn't know what it was.

And what I found interesting, is that it is considered the fourth stage of matter, i.e. Solid, Liquid, Gas, Plasma. Really? When did that happen? When I was growing up, we were only taught about the first three. It stands to reason that plasma would be right in there like a dirty shirt, but seriously, when was it decided that it was a state?

I assumed I'd have to read through a lot of long-winded, dry, technical papers on plasma to find the answers I was looking for, but right off the bat found an article that was right up my alley. (I love Google) The author has summarized it so well, that it would be redundant for me to try to further summarize it, so I'm posting it below for your review in the off-chance that you give a toss about plasma.

Say what you will about us Trekies, but I personally find great value in watching the shows. They're jam-packed with good, wholesome, family values -- you know, the kind you could watch with your kids (or parents as the case may be) and have a valid discussion on afterwards about the life lessons learned, etc. Or, if you're like me, you can totally geek out on vague references to something and go off on a tangent boring your friends out of their freakin' minds.

Original post: http://www.madsci.org/posts/archives...6828.Sh.r.html

Re: how was plasma discovered
Date: Thu Nov 2 05:48:27 2000
Posted By: Javier Castellano, Grad student, National Laboratory for Nuclear Fusion; CIEMAT - Spain
Area of science: Science History
ID: 970430278.Sh Message:

The answer I am to give you is maybe related more with the 'When' rather
than with the 'How', but I hope you'll find it interesting anyway.

It could be surprising to you but, as the other three common states of
matter (solid, liquid and gaseous), the Plasma State was 'discovered' by
the first human beings on Earth. This is true if you consider that 'to
discover' is just to realize there's something new and unseen, even if
you can't explain or understand it. Plasma State appears on Earth in
three basic forms: lightning, fire and Aurora Borealis (Northern Lights).
Them all are plasmas as they are made of partially ionized gases (that's
what a plasma is), and were known by prehistoric humanity.

Greek philosophers (400-500 B.C.) gave the first 'theory' of matter,
establishing that everything was made of a mixture of four elements:
Earth, Water, Air and Fire.
Because of the properties they gave to those elements we could compare
them with modern states of matter:

Earth -> Solid State.
Water -> Liquid State.
Air -> Gaseous State.
Fire -> Plasma State.

As in many other subjects, greek philosphers made a great job on
identifying and clasifying matter states and properties with nothing but
their intuition and intelligence (they used no technology or

But if we have to be strictly scientifical in the modern sense, the
privilege of discovering the Plasma State has to be given to the English
scientist W. Crookes, who, in the late-middle 19th. Century, was studying
the effect and behaviour of gases at low densities when an electric
discharge were forced inside a tube filled with them. He realized that a
new medium appeared such that an electric current could pass through it
(gas inside the tube became ionized and therefore electrically
conducting, i.e. plasma were created). By then he wrote

''...The phenomenon in these exhausted tubes reveal to physical science a
new world, a world where matter may exist in a fourth state ...''.

So he was the first on describing an ionized gas as a new state of
matter. The answer to your question would then be that the Plasma State
was discovered in the 19th Century while studying electric discharges in
low density gases.

But the answer wouldn't be complete without mention of many other
scientist who, some years later, developed Plasma Physics.

First of all I should mention Irving Langmuir. He was the first on giving
a complete and appropiate theory of ionized gases, and was also the first
on using the name 'Plasma' to refer to this new medium or state of
matter. This happened by 1920's, when some other scientists (L. Tonks, R.
Seeliger, B. Klarfeld, M. Steenbeck ...) were also studying inozed gases.
By that time other physicists (Saha, Chandrasekhar, Spitzer, Alfven,
Houtermanns, Atkinson ...) realized the presence and importance of
ionized gases in outer space, as well as the role they play in nuclear
fusion reactions in star nuclei, increasing the relevance of Plasma
Physics on understanding nature (as matter in stars is mainly in the
plasma state, it is said that probably over 99% of matter in the whole
Universe is in the plasma state).

I hope this answer had been what you expected. Almost all the information
I used for writting it has been extracted from the introduction to the
book ''Plasma Physics'' by J.G. Linhart (North-Holland, Amsterdam -
1960). There are mountains of books devoted to the study of Plasma
Physics. Almost all I know are specialized books written for physicists,
so could be very hard to read.

To search for more information on Plasma Physics and related topics you
better surf and visit the links listed here (most of them treat Nuclear
Fusion as well as Plasma Physics, as Nuclear Fusion is the main field of
application of plasmas being studied nowadays):

* http://fusion.gat.com/PlasmaOutreach/
(Various USA Universities and Laboratories have developed a program
called 'Plasma Sciences and Technologies Education Outreach' with the aim
of getting ready a place to learn about Plasma Physics and Nuclear

* http://FusEdWeb.pppl.gov/
(Princeton University Plasma Physics Laboratory)

* http://www-istp.gsfc.nasa.gov/Education/whplasma.html http://astro-2.msfc.nasa.gov/academy...LASMA_PHY.HTML
(NASA's pages on Plasma Physics History and Theory)

Enjoy... and keep on thinking.