The 20K limit IS a fact and YOU should be ashamed of YOURSELF for calling one of your betters a liar. You normally scale lifting events (to see who amongst the champions of the various weight divisions has actually done the best lift regardless of weight) by dividing through by 2/3 power of weight, which inverts the difference due to the square/cube thing. That also says you could simply solve for the point at which one of our very strongest athletes needs the same effort just to stand up as he needs to do one of those 1000-lb squats or deadlifts at his normal weight, i.e. the athlete plus the bar divided by just the athlete's weight to the 2/3 power on one side of the equation and x divided by 2/3 power of x (the guy just standing up) on the other, something like 1350/350^.67 = x/x^.67 and solve for x; x turns out to be around 20,000 lbs.
That would be the extreme mathematical limit for the world today, the actual limit for real creatures is the 14,000 - 15,000 lb size of the largest elephants.
A sauropod dinosaur would be crushed by his own weight in our present world, present gravity, that's why they no longer exist. Same thing for flying creatures, weight is proportional to volume and the ability to fly is limited by surface area of wings amongst other things, another squared figure while volume is a cubed figure. The largest creatures which can take off or land in our present world are bustards, berkuts and albatrosses at around 25 - 30 lbs, while there were 200 - 1000 lb flying creatures in past ages.
varmintman:
"The 20K limit IS a fact and YOU should be ashamed of YOURSELF for calling one of your betters a liar.""...divided by just the athlete's weight to the 2/3 power on one side of the equation and x divided by 2/3 power of x (the guy just standing up) on the other, something like 1350/350^.67 = x/x^.67 and solve for x; x turns out to be around 20,000 lbs."
No honest person is lesser than you, pal, none.
You "explanations" are rubbish to the core, and I'm certain you know that.
That makes you lesser than every decent person.
You have done no studies -- zero, zip, nada -- on the strengths of bones, muscles & joints in very large four-legged land-creatures, you have merely extrapolated based on what you think you know about human anatomy.
Those scientists who actually studied the question (i.e., here and here) report suffering no such fantasies as your allegations about changing gravity.
Yes, it's true, there are not a large number of land-creature fossils estimated over 20,000 lbs.
But there are some, and they include examples from the age of dinosaurs (65+ mya), Oligocene (circa 25 mya) and even into the Holocene (10,000 years ago).
Nothing in these examples suggest changing gravity.
