Despite humans being able view to the moon, stars and galaxies, we cannot live very well beyond the outer limits of our globe. Those two astronauts that got stuck on the international space station had to be carted off in wheelchairs up after their planned 8-day trip turned into a grueling nine months. A person can live three weeks without food, three days without water and only three minutes without air.  Despite its vastness, space provides only as much of those as we take with us. We may have Star Trek dreams for the future, but we have to survive our current reality first.

There are no spare Earths.