> What are the implications of this on black hole entropy and temperature? Can black holes evaporate from gravitational radiation alone without Hawkins radiatio

> What are the implications of this on black hole entropy and temperature? Can black holes evaporate from gravitational radiation alone without Hawkins radiation? No, gravitational waves are only generated when you have large masses moving. When two black holes merge, they become a single spinning mass which then becomes uniform very quickly. Once the mass is uniform, it doesn't generate gravitational waves from rotation. I have yet to study cosmology (I did some research in astroseismology), so I can't answer general cosmology questions.