Phys.Org has an article about a report on the extinctions of the Neanderthals. Neanderthals' failure to make parkas may have sealed their demise

The study suggests that the Neanderthals died out because they couldn't protect themselves from the cold weather of the ice age. Modern humans however could make cold weather clothing from animal skins.

The first problem I have with that is that they lived through the much worse ice age at about 100,000 years ago. This was long before they became extinct.

Bill Gill

C is not the speed of light in a vacuum.
C is the universal speed limit.