In general, astrophysicists believe that formation of very small dwarf galaxies should be suppressed. This is because gas required for continued formation of stars can be heated and expelled by the first generation of exploding supernovae stars. In addition, ultraviolet radiation from galaxies and quasars that began to fill the universe approximately 12 billion years ago heats the intergalactic gas, shutting down the supply of fresh gas to dwarf galaxies. Andrey Kravtsov found that some of the dwarf galaxies that are small today have been more massive in the past and could gravitationally collect the gas they need to form stars and become a galaxy. The result puts the cold dark matter scenario on more solid ground.