Signature of dark matter. First in a series of three colour-coded images showing a possible gravitational lensing event by a brown dwarf star in the halo around our galaxy. The arrow points to a star in the Large Magellanic Cloud (LMC) before the lensing event. A brown dwarf is a type of star-like object too small to 'burn', and is thus almost invisible, but still has a gravitational field strong enough to act as a lens. As a type of MACHO (Massive Compact Halo Object) it could help account for the missing 'dark matter' which should make up about 90% of the mass of the Universe. Compare with R670/045 and R670/046.