Although I agree, in our solar system nothing compares to earth. It is all the more reason to protect, defend and restore the Blue Marble. A planet so extraordinary even the most inhospitable regions are teeming with life. The universe is probably also full of life (a nearly statistical certainty). The planets of other life forms or other uninhabited planets, may not be anywhere near as perfect as earth is for humans. The only good reason to colonize any other planet in our solar system, would be to save the human species from extinction due to an eventual meteor strike or solar flare. More likely the catalyst will be resource extraction. However the need to explore and gain knowledge of the unknown is ingrained in our DNA. Many incredible, life changing discoveries await the human exploration of the cosmos.