About leaving Earth

My view on the subject of leaving earth is that if we can't leave the star system with the current planet we live in (like attaching a giant rocket to its side) we can't do it with a spaceship made out of a part of that planet. (reducing the size and ratio of energy/people)

If you grow plants on the ship, where does the alternative sunlight for those plants come from?(and they need much more than that) And if that is produced with lights, where does the energy for those artificial light sources come from? The energy sources on the ship has to last for the entire trip, because there is no way of charging it e.g. sunlight, because leaving the star system kinda rules that one out. 

There are other problems as well, like how to generate heat without running out of energy or how to get rid of excess heat if that builds up. And of course the ever present time, how long does it take to travel to someplace else, like the man[Bill Nye] said: No place to go 

So the only way seem to be those wormholes, or some other "unconventional" mean. 

I don't know why there is this urge to leave this planet, it's very sustainable compared to the others around there. What is it that we can't have here? What is it we are trying to escape or reach, ourselves? But I guess the grass is always greener..