Manx flag is Greek to me
QUESTION What is the origin of the three legs on the Isle of Man crest?
This ancient symbol is derived from early representations of the sun, such as the tri-spiral design on ireland’s Neolithic tomb at Newgrange, Co. Meath.
One of the earliest examples of the three legs is on the shield of Achilles on a Greek vase.
Various 13th-century heraldic manuscripts, including rolls of arms, contain descriptions of the Three Legs of Man. Walford’s Roll, compiled in 1275, has two descriptions of the design.
There may be a royal connection why the three legs took over from the Viking ship as the symbol of the island.
At the turn of the 12th century, Magnus iii was the last king of Norway to style himself King of Man. his symbol was a mailed leg, bent at the knee. After failing to take the island by force, scotland’s Alexander iii bought the island from Magnus’s successor.
Alexander’s wife Margaret was the daughter of henry iii and sister to Edmund Crouchback, who was styled King of sicily, though he never ruled there. The sicilian flag has three naked legs with a face superimposed where the legs join.
The three-legged symbol may have been adopted as a means to reinforce the regime change on the isle of Man.
There is an ongoing debate about which way the legs should run. The heraldic definition doesn’t specify so the arguments continue, as described in my book Three Legs Good: The story Behind The Manx Triskelion (Loaghtan Books).
Sara Goodwins, Manx bard, Maughold, Isle of Man.
QUESTION Is it true that if two pieces of the same metal come into contact in space, they become stuck together?
This is a process called cold welding. it can occur between different metals, but it is most likely to happen if they are structurally similar. A metal is a lattice of positively charged ions embedded in a sea of negative electrons.
On Earth, the surfaces of these metals react with oxygen to create a protective oxide layer. in space, this may be worn away, such as in a hinge where two pieces of metal slide over each other. The electrons can flow from one piece of metal into another, forming a cold weld.
Physicist Richard Feynman explained the phenomenon thus: ‘The reason for this unexpected behaviour is that when the atoms in contact are all of the same kind, there is no way for the atoms to “know” that they are in different pieces of copper.
‘When there are other atoms, in the oxides and greases and more complicated thin surface layers of contaminants in between, the atoms “know” when they are not on the same part.’
Fortunately, it has not proved to be a serious problem in space. Only perfectly clean surfaces will weld together in this way; in practice, most metal surfaces are contaminated with oxide, dirt or grease.
A costly example occurred in 1991 when the high-gain antenna of the Galileo spacecraft, designed to study Jupiter and its moons, failed to unfurl because its ribs had cold welded. Nasa ended up using the low-gain antenna, which had 0.01 per cent efficiency of the original.
Cold welding is useful in nanotechnology where it is extremely difficult to pinpoint heat onto wires. Engineers can cold weld single crystal gold nano wires in a vacuum, forming perfect bonds.
Keith Bulley, Lewes, E. Sussex.