GEOLOGISTS WHAT DO YOU THINK OF THIS?

Most geologists now accept the cold accretion theory. In this theory, the crust or outer mantle were never fully molten. Most life could die if there was warming, but the extremifiles that live kilometers down would be difficult to kill. In 4.5 billion years, we may be just about due for the sun to turn into a red giant. Your scenario is possible but obviously returning to our present state would be pretty unlikely. It would be a slightly different environment possibly favoring different forms.