Using a huge telescope orbiting the sun, scientists just found 1,200 new planets. 68 of them are about Earth's size. 54 of them are Earth's size AND temperature – meaning they are potentially habitable.
The last time humanity discovered habitual masses across an unknown abyss it was North America. In the 500 or so years since, we've experienced an unprecedented flowering of commerce, science, and culture. Back then, the average life span was 30 to 40 years.
Sure, some bad things happened as a result of this adventuring and colonization. Peoples disappeared. Disease spread. Buffallo died.
But on the whole, it looks like the Spaniards, Dutch, and Portugese were pretty smart to pack entreprenuers onto ships and send them into the unknown.
Let's do it again! It'll be dangerous, slow-going, technically difficult, and not immediately fruitful, but that was the case last time too.
(If humanity wants to keep going, by the way, we're going to have to find a new home eventually anyway. The sun won't last forever.)