Ask any roomful of high school students to name the four states of matter, and chances are they'll laugh at the question. Everybody knows there are only three states of matter: solid, liquid, gas -- right?

Wrong. They will be very surprised to learn that 99 percent of the visible universe is composed of none of the above, but exists instead in a "plasma state," often referred to as the fourth state of matter.

Very few of us know what plasmas are, likely confusing them with the straw-colored liquid administered to wounded troops on MASH re-runs. The plasma state is a gaseous collection of electrically charged particles with nearly equal numbers of negative particles and positive ions. Plasmas have their own unique qualities just as solids, liquids and gases do. Though they can exist at low temperatures, they typically come into existence when gases are heated to very high temperatures.

Plasmas in their myriad forms and applications are all around us, serving us and making our lives better in many ways. They light up our offices and homes, make our computers and electronic equipment work. They drive lasers and particle accelerators, help clean up the environment, pasteurize foods, and make tools corrosion-resistant. Someday, they may drive spaceships and heat our homes. To paraphrase Churchill, never has so much of what is around us been understood and appreciated by so few.

It is in these applications that the social and economic importance of plasmas lie -- and where the concerns of today's plasma scientists lie. Technological applications typically grow out of knowledge -- out of pure science performed to gain understanding. The stronger the scientific understanding, the more benefit we are likely to extract from our knowledge. In the case of plasmas, though, the many technologies that employ plasmas are built on an aging foundation of basic knowledge. Core activity in plasma science, a 1995 report from the National Academy of Sciences' National Research Council (NRC) warned, is "dangerously small." The steady stream of technological advance, which is based for the most part on research done in the 1960s and 1970s, is at risk of drying up unless its scientific headwaters are replenished.

Alarming though it is, the NRC report was not news to the scientific community. A study done in 1986 called the Brinkman report reached many of the same conclusions, stating that direct support for basic plasma-physics research had "practically vanished" in the United States.

The problem is that plasma science is not the stuff of headlines; it is little understood or appreciated by the public, media, educational community and policy-makers. As a result, support for basic research, and the pace of technological innovations stemming from plasma science are all impeded.

Plasma's problems are exacerbated by the fact that its applications reach across a wide spectrum of technologies and businesses. No single application dominates; no single scientific discipline claims it; there are no "departments of plasma science," and plasma science is rarely a tenure-track profession. No single agency dominates government support as is common with other fields of science. Plasma science has been called a science without a home.

The result is apparent. "There is no effective structure in place to develop the basic science that underlies the many applications of plasmas," the NRC report states, "and if the present trend continues, plasma science education and basic plasma science research are likely to decrease both in quality and quantity."

Because plasma science has more applications than advocates, several companies, individuals, and associations joined together to create the Coalition for Plasma Science. The goal is deliberately transparent: to attract more interest to the science among academics, school-age talent, the media, and policy-makers. More coordination of plasma science activities among government agencies ranging from NASA to the Department of Defense will also help significantly.

Learn more about the Coalition for Plasma Science, its activities and events, and how your organization can become a member.

In the beginning there was plasma.

The other stuff came later.

When students are told of the states of matter, they are usually told only of three: solid, liquid, and gas. Those are the states we experience most directly and most often in everyday life. The students are most aware of those states, and they can relate to the idea of adding heat to break bonds between molecules to move from one state to the next.

Rarely is the fourth state in the sequence mentioned -- the state resulting from adding energy to a gas to break the internal bonds of its individual atoms, ionizing those atoms and freeing electrons. When this happens to a significant number of atoms, the resulting collection of electrically charged particles forms an ionized gas -- or a "plasma" -- with unique properties.

As for the importance of material states in our larger world and in our lives, the usual ordering belies the truth of the matter. Not only should plasma be added to the list, but the order should be reversed to put plasma in first place. The Big Bang beginning of our universe was dominated by high-temperature plasma, and plasma continues today to comprise more than 99 percent of our visible universe. It's where we all came from, and it continues to play a major role in our universe and -- albeit not so apparent to the casual observer -- in our more immediate surroundings.

While solids represent familiar material in our immediate earthly surroundings and generally represent the coolest state (in the sense of temperature, not teenage sociology), starting the list with that material misses an important point. In general, material in various states in our universe was not formed by heat added to a more strongly bonded state; rather, it was formed by heat removed from a hotter, more weakly bonded state. That is, stuff is usually formed by cooling. As matter cools, it reaches temperatures at which the atoms and molecules bind together, condensing to form the next state of matter in the cooling sequence. The high temperatures that existed early in the universe clearly correspond to the presence of plasma, not the lower-temperature gases, liquids, and solids that would develop later.

The predominance of plasma in the early universe continues today. While the material in our immediate surroundings is mostly of the cooler varieties, plasma remains the most prevalent form of matter overall. It is the stuff of our sun and of other stars and of the vast interstellar space. Thus plasma not only precedes the other states in time and is their progenitor, it also dominates by occupying most of our universe.

Plasma is also in our more immediate surroundings. It is the stuff of lightning, of computer chip manufacturing, and of lamps that are the light of our lives. In the future it will likely be the stuff of propulsion for interplanetary travel, of flat panel televisions, and of electric power generated from fusion.

Thus plasma deserves respect both as an ancestor and as a major player in our world. There is no question but that the usual sequence of states of matter should be reversed, with plasma not merely added to that list, but put first to lead that list.

Copyright (c) 1998 G. L. Rogoff

Dr. Gerald Rogoff is Chairman of the Coalition for Plasma Science, where he represents the IEEE Nuclear and Plasma Sciences Society. A plasma physicist with extensive research experience in industry, he is presently part of Plasma Associates, a consulting organization for issues related to plasma science and its applications.