Originally Posted by Joshua G

i read debates about this all the time. Hawking says we must leave this planet within 1000 years or we will be extinct.

but why does anyone think people can live outside earth? cause star trek says so?

fact is, many things are required on earth for us to live. The planet must be in the habitable zone. there must be abundant water. there must be a specific mixture of gases in the air, including oxygen. the earth must be tilted so there are seasons. there must be a magnetic field to protect us from cosmic rays. there must be ozone to protect us from UV rays. there must be a moon to provide a stable earth orbit around the sun. there must be a stable climate over thousands of years, no ice planets, supervolcanos or asteroids. we need to live with an air pressure of 14psi, & we need gravity. Need fertile soil to grow plants, & abundant land for both the plants & animals we eat.

the next closest planets are venus & mars. they are too hot, & too cold. no atmospheres. the next star is 24 trillion miles away. it takes a decade just to launch a robot to photograph Pluto, only 3 billion miles away. any human population traveling outside the solar system will reproduce into something not human in a gravity free environment.

we can barely get 3 people to live 6 months in an enclosed tube only miles outside earth orbit. How is the whole human race going to live without earth? & who would want to live inside a tube, with no gravity, no outdoors, for all their lives?

pipe dream.