New constraints on macroscopic compact objects as dark matter candidates from gravitational lensing of type Ia supernovae

We use the distribution, and particularly the skewness, of high redshift type Ia supernovae brightnesses relative to the low redshift sample to constrain the density of macroscopic compact objects (MCOs) in the Universe. The supernova data favor dark matter made of microscopic particles (such as the lightest supersymmetric partner) over MCOs with masses between 10(-2)Mo and 10(10)Mo at 89% confidence. Future data will greatly improve this limit. Combined with other constraints, MCOs larger than one-tenth the mass of Earth (approximately 10(-7)Mo) can be eliminated as the sole constituent of dark matter.