Note that different people have different research approaches. The two old ladies check that none of them can see herself and the problem is solved! ;-)
The other older lady makes an experiment with motion and rigorously determines that she is ... well ... unsichtbar. :-)
How Global Warming Will Someday End Life On Earth (Synopsis) - “We have known since the 1800s that carbon dioxide traps heat in the atmosphere. The right amount keeps the climate conducive to human life.” -James Hansen...
12 hours ago