Birkeland was among the first to speculate that the Northern Lights were charged particles ejected from the Sun, captured by the Earth's magnetic field, and directed towards the polar atmosphere. To prove this theory, Birkeland performed his famous 'Terella' experiment, where he artificially created the aurora in the laboratory. His theories were initially laughed at, and it is only now in the space age that measurements from satellites are proving Birkeland correct.

Significantly, his approach to science was broad, comprising observation and laboratory experimentation in addition to mathematical modelling. He was not content with a merely theoretical approach, despite having trained as a mathematician himself.

He is probably Norway's greatest ever scientist, and many of his works are still used as reference materials. The electric currents that flow from space are named after him — Birkeland currents. He is recognised for bringing plasma and electromagnetism into cosmology, but while many of his ideas are widely accepted, his cosmological theories are less well known. He died aged 49 just when a working committee was in the process of nominating him for the Nobel Prize in Physics.

Langmuir (1881-1957) was the first to use the term 'Plasma' in 1927, borrowing it from Blood Plasma to describe the almost life-like and self-organising behaviours of a plasma when in the presence of electrical currents and magnetic fields.

He discovered Plasma Sheathes, now called Double Layers, having observed the electrons and ions of a plasma separating during experimentation. DLs are one of the most important features of plasma behaviour. He also defined and explained the term 'valence' as part of his description of the atom. Few textbooks, however, recognise the influence that Langmuir had on the development of our understanding of the nature of the atom.

He became the first 'non-academic' chemist to receive the Nobel Prize, an accomplishment he realised in 1932. Langmuir probes, which can be used in space, are named after him.

Alfvén (1908-1995) is generally regarded as the Father of modern Plasma Physics. He continued the work of Birkeland, feeling very much in spirit with him, and eventually won a Nobel Laureate for his ground-breaking contributions. He was not always highly regarded by the scientific establishment because of his controversial ideas, however, and suffered no little condescension and ridicule in his lifetime.

In fact, it now seems bizarre that he wasn't awarded the Nobel Prize until 1970, especially considering his many fundamental accomplishments. For some time he was forced to publish in journals that did not enjoy international readership. His ideas finally became known to the general scientific community through his ground-breaking book, Cosmical Electrodynamics, published by Oxford University Press in 1950.

Alfvén took a practical and intuitive approach to science, insisting that theories of cosmological phenomena must agree with laboratory experiments. (The definition of 'laboratory' being broadened to include experiments in space.) Having started out as an engineer, his methods were in direct opposition to the approach generally favoured by Big Bangers, that of starting-out from idealised mathematical principles.

In 1937 Alfvén proposed that our galaxy contained a large-scale magnetic field and that charged particles moved in spiral orbits within it, owing to forces exerted by the field. Plasma carried the electrical currents which create the magnetic field.

While many of Alfvén's theories are now well known, like those of Birkeland, the cosmological implications of his work also remain to be fully recognised. Ironically, some have put this down to the very simplicity of many of these ideas.

"The universe is an unending transformation in flux whose previous states we are not privileged to know." David Bohm

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