<Table> Plasma <Tr> <Td_colspan="2"> </Td> </Tr> <Tr> <Td_colspan="2"> </Td> </Tr> <Tr> <Td_colspan="2"> Top: Lightning and neon lights are commonplace generators of plasma . Bottom left: A plasma globe, illustrating some of the more complex plasma phenomena, including filamentation . Bottom right: A plasma trail from the Space Shuttle Atlantis during re-entry into Earth's atmosphere, as seen from the International Space Station . </Td> </Tr> </Table> <Tr> <Td_colspan="2"> Top: Lightning and neon lights are commonplace generators of plasma . Bottom left: A plasma globe, illustrating some of the more complex plasma phenomena, including filamentation . Bottom right: A plasma trail from the Space Shuttle Atlantis during re-entry into Earth's atmosphere, as seen from the International Space Station . </Td> </Tr> <P> Plasma (from Ancient Greek πλάσμα ​, meaning' moldable substance') is one of the four fundamental states of matter, and was first described by chemist Irving Langmuir in the 1920s . Unlike the other three states, solid, liquid, and gas, plasma does not exist freely on the Earth's surface under normal conditions . Plasma can only be artificially generated by heating or subjecting a neutral gas to a strong electromagnetic field to the point an ionised gaseous substance becomes increasingly electrically conductive, and long - range electromagnetic fields dominate the behavior of the matter . </P> <P> Plasma and ionised gases have unique properties and display behaviors unlike those of the other states, and the transition between them is mostly a matter of nomenclature and subject to interpretation . Based on the surrounding environmental temperature and density, partially ionised or fully ionised forms of plasma may be produced . Neon signs or lightning storms are examples of partially ionised plasma, while the interior of the Sun is an example of fully ionised plasma, along with the solar corona and stars . </P>

When did plasma become a state of matter