"Geologic time/millions of years ago ( mybp ) /days per year late Precambrian/900mybp/487 days earliest Cambrian Period/600mybp/424 days early Ordovician Period/500mybp/412 days middle Devonian Period/370mybp/398 days Permo-Triassic boundary/245mybp/386 days `` Jurassic Park `` /180mybp/381 days end Cretaceous ( Chixulub ) /65mybp/371 days"
"But that does n't help much with calculating the length of a day from actual astronomical observations . Perhaps if we told Freeofthought that the current rate of slowing of the earth is 0.005 sec/year/year . I have no doubt that Freeofthought will misunderstand that number - it is a rate . Just assume that rate has been unchanging even though it has n't been . A lot of the creationists misunderstanding comes from remarks like the following ."
"Geologic time/millions of years ago ( mybp ) /days"
"But that does n't help calculating the length of a day from actual astronomical observations ."