English name for the constellation Lupus.

A measure of the sunspot activity on the solar disc, taking into account spot groups as well as individual spots. It was devised by Rudolf Wolf of the Zürich Observatory, and is also known as the Zürich sunspot number. The value, R, is calculated from the formula R=k10g + f where g is the number of sunspot groups, f the total number of spots and k a weighting factor depending on the instruments used and the observer. The value of k is about 1 for telescopes of 100 mm aperture.

A small irregular galaxy belonging to the Local Group. It lies at a distance of 2.8 million light years.

A member of a class of rare, exceptionally hot stars with surface temperatures of 20,000-50,000 K. Their spectra show strong broad-band emission lines: in WC stars, carbon dominates, whereas in WN stars the dominant emission lines are of nitrogen. It is believed that there is a genuine difference in composition between the two subgroups. The emission lines are thought to originate in a rapidly expanding envelope through which the star is losing mass. Some are the central stars of planetary nebulae, but their evolutionary status is not fully understood. The name comes from two nineteenth-century French astronomers, Charles Wolf and Georges Rayet.

wormhole A hypothetical tunnel-like structure in the fabric of spacetime. Theorists have suggested that on the distance scale of the Planck length 10 to the power of -35 metres, spacetime might have a foam-like structure, riddled with wormholes. It might be possible for such a wormhole to pinch off and form a new universe.

A low-relief feature on the lunar surface which may extend for hundreds of kilometres across a mare. Wrinkle ridges appear to be a feature associated with volcanic activity and the flow of lava in the Moon’s distant past.