Supercluster which contains Virgo group, in which you find our local group (Milky Way but also Andromeda Galaxy).
Gold formed from collision of 2 neutrino stars (themselves remnants of bigger, older stars?)
Dark matter postulated because stars spinning in a galaxy spiral do not move at expected speeds, also difficult to explain formation of galaxies at all. Must have been created at time of inflation, quantum mechanics suggests a range of particles eg MACHOs and WIMPs (weakly interacting massive particles).