h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I want to pick up on two points in this article:
a) The general protection afforded by the Earth's atmosphere.
b) Space Junk.

Watching 'Living with Dinosaurs' on BBC recently, combined with listening to BBC Radio 4's 'This Sceptred Isle'
on Tape.. it seems to me that there have been a large number of 'helpful contributory factors' (HCFs) that give our world the form that it takes today. Many of these HCFs in Recent History seem to have taken a human form.. but in more distant history we cannot continue this naturally occurring arrogence. Instead we have to accept that non-human HCFs have had a profound influence in our development..

One example is the earth's atmosphere which protects us from externally produced space litter and then there is of course the result of our own early failures .. Space Junk.

Another example is one I only recently heard about.. 'man's best friend'. Recent research has shown that it is possible that if men and dogs had not set up a working relationship many thousands of years ago.. it is possible that we would not have been able to evolve away from the large organs of 'smell' that we used to rely upon for our survival. Our brains were freed up to grow faster and the resulting avalanche of technological progress is now here for all to see... and all because we chose to co-operate and work together with another species...

Of course there are many other exmaples of HCFs that have helped us along the way... perhaps you have some other examples that you would like to share with us here .... thanks for listening !