It is sometimes said that astronomy is the crossroads of physics. In the same spirit, it can forcefully be argued that galaxies are the crossroads of astronomy. Internal pro ces …
Supernova explosions are not only important to the ecology of the universe, seeding it, among other things, with the heavy elements necessary for the existence of life, but they …
Historically, the discovery of tools, or evidence that tools have been used, has been taken as proof of human activity; certainly the invention and spread of new tools has been a …
