10 Reasons Why Humans May Not Have Come From Earth

11. Bad Backs

If we evolved on this planet, why does just standing up on it hurt us?

Silver argues that the gravity on our home planet must've been stronger, and so we're progressively growing taller and taller with each generation, causing us to have bad backs. 

It is thought, in the wider scientific community, that on planets with stronger gravity, human-like life forms would evolve to be much shorter and stockier to deal with the extra gravity bringing them down. 

When that gravity isn't there, we apparently start to grow like forced rhubarb, ending up so tall and willowy that our own skeletons can't support us very well.

There could also be a counter argument that the gravitational pull on our home planet is, in fact, weaker, and the fact that our bodies will slowly bow to the pressure of Earth's gravity over our lifetimes is proof that we evolved to deal with weaker gravity. 

As we grow older, we hunch over and even shrink, gravity slowly wears us down, starting with a crick in the neck and ending with a hunchback.

Silver also wonders about the possibility that the food on this planet is more nutritious than on our home planet, causing a growth spurt. 

If we spent all our time back home chewing on tough, woody vegetation (yum), then were sudden plunged into a world of strawberries and fillet steak, it's possible that all of those abundant nutrients made us shoot up like a 14-year-old boy who lives on McDonalds and Red Bull.