Dimethylmercury ((CH3)2Hg) is an organomercury compound. This colorless liquid is one of the strongest known neurotoxins. It is described as having a slightly sweet smell, although inhaling enough vapor to detect its odor would be hazardous.
The formation of a star begins with gravitational instability within a molecular cloud, caused by regions of higher density-often triggered by shock-waves from nearby supernovae (massive stellar explosions), the collision of different molecular clouds, or the collision of galaxies (as in a starburst galaxy).
Gravitational collapse is the mechanism that reduces the lateral variations in GPE that have developed during the thickening of the crust. (Rey et al, 2001). Gravitaional collapse is driven by the gravitational force (as described in the previous section). This force acts internally to the system.