4.22 is roughly the number of light years from Earth to the closest star in the Alpha Centauri system, Proxima Centauri. Just to be clear 4.22 light years works out to roughly 39,900,000,000,000 km, this is a really big number.

Recalling an earlier post, ap­prox­i­mate­ly 262.1 billion vehicle miles were estimated to have occurred in US for May 2013. If we ex­trap­o­late the May travel figure out over 12 months then it would take ~7.9 years at 262.1 billion miles per month to travel the distance between Earth and Proxima Centauri.

It’s hard to describe and comprehend the distances involved when it comes to travel off our planet.