Scots father of the stealth fighter

Published on Friday 17 June 2005 10:09

SHHHH! Keep it to yourself, but the scientist whose discoveries led to the development of the US's stealth fighter was actually a Scot: James Clerk Maxwell.

ResourcesMaxwell in his later years. Picture: complimentaryGreat Scots: James Clerk Maxwell But the physicist - whose pioneering work on radio waves is still considered at the cutting edge of military technology more than a century after his death - is still little known outside of the scientific world.

Maxwell's story begins in Edinburgh, where a plaque in the city's New Town marks the house in which he was born. The main physics building of Maxwell's alma mater, Edinburgh University also bears the name of the scientist variously described as "brilliant" and "head and shoulders above anyone of his time".

The path of discovery takes us from Aberdeen, where Maxwell chaired the city's historic Marischal College; to Cambridge, where Maxwell's discoveries were lauded by his fellow academics at Trinity College; and finally to the military and communications establishments in the United States and the top-secret business of defence technology.

Maxwell's discoveries laid the foundations for predicting the behaviour of electromagnetic waves, or radio waves, on a flat surface area, key tenets of which were used by the US to develop its F117A stealth fighter, which has a radar signature, or "footprint", the size of a marble.

At the time of development, a former vice-president of American defence contractor Lockheed-Martin praised research based on Maxwell's findings as "the Rosetta Stone breakthrough for stealth technology''.

And as Dr John Chapman, the head of physics at Glasgow University, notes, Maxwell's equations foretold the development of surfaces which "absorb rather than reflect" radio waves.

Maxwell's theories - later built on by Soviet scientists during the Cold War, though the Communists were not actively seeking stealth technology - are also employed in the B2 bomber, used in multiple missions in the most recent Gulf War. Despite its 172-ft wingspan, the B2 bomber has a radar footprint the size of a golf ball.

Stealth technology, described as more of a "concept" than an overarching set of principles, allows an aeroplane to "hide" from enemy radar by using angled surface areas to deflect and disrupt radio waves. Normal cockpits, for example, bounce radar straight back to the source, so they must be coated with special materials. Tail surfaces are designed at a sharp angle, as opposed to vertical, enabling them to "bounce" radar in different directions.

But Maxwell's achievements were not limited to stealth - he also pioneered colour photography with the development of the spectral-colour triangle, and developed his own ground-breaking kinetic theory of gases.

The colour spectrum triangle, known as the CIE, after the Commision Internationale de L'Eclairage (illumination), was built on a series of lectures Maxwell performed at the Royal Institute in London in 1861, in which he showed that by superimposing three primary colour filters over a black-and-white photograph, a "colour" photograph would be revealed.

These discoveries will forever be associated with Aberdeen University where Maxwell took the chair of physics at Marischal College in 1856. Aberdeen's current head of physics, Dr John Reid, says: "His work had massive implications for physics, and artists, too."

It was also in Aberdeen that Maxwell began his famous research into Saturn's rings, his ultimately successful entry into Cambridge's prestigious Adam Prize.

In this "tour de force on theoretical physics" Maxwell postulated that the planet's rings must be composed of small bodies, as opposed to, say, liquid. While at Glenlair, in Kirkudbrightshire, Maxwell in 1857 detailed his discoveries in a letter to a friend:

"I have effected several breaches in the solid ring, and now am splash into the fluid one, amid a clash of symbols truly astounding. When I reappear it will be in the dusky ring, which is something like the siege of Sebastopol conducted from a forest of guns 100 miles one way, and 30,000 miles the other, and the shot never to stop, but go spinning away round a circle, radius 170,000 miles."

Maxwell's discovery was verified over a century later by the space probes Voyager and Cassini-Huygens; his contention that there could be small waves in the rings was also found to be accurate.

Maxwell's work, though little recognised, lives on through his partnership with fellow Scots physicists Peter Tait and David Gill and through further research by luminaries such as Andr-Marie Ampere, Heinrich Herz and Albert Einstein.