The mixture of ytterbium, gallium and germanium neither expands nor contracts on heating, and also conducts electricity, according to a study published on Thursday in Nature, the British science weekly.

The study, led by Mercouri Kanatzidis of Michigan State University, theorises that as the material warms, electrons move from the ytterbium atoms to gallium atoms.

In doing so, the ytterbium atoms shrink, making up for an increase in the size of gallium atoms.

Thermal expansion and contraction are a headache for spaceships because they can inflict tiny holes in a metal that can enlarge with the buffeting of re-entry and potentially widen to become mortal cracks.

SPACE.WIRE