We already have explored almost every corner of the Earth and migrated there. But time is coming and so it is our foe. We need a new planet to call home and to explore. It is the urge within us. Already scientists such as Stephen hawking are suggesting we must migrate to other planets or the human race may not even survive a 1000 years if we do not migrate.
Now for those saying there is chaos on Earth and that we should tend to it first. I say then what if we fail? What if we dig ourselves deeper into the trouble. We should spend more on space so we can find potential worlds to live on. Also, there are risks such as the huge amounts of methane trapped under the seafloor. At any moment an old ww2 sea mine could go off or even a nuclear bomb test could result in all the methane to escape and be released into the atmosphere (keeping in mind that methane can trap heat 5 times MORE efficiently than carbon dioxide) It wouldn't take long for most of us to die due to the heat trapped. A backup planet doesn't sound so much worse now does it?
Also, don't you get that feeling of excitement and curiosity what's out there in the vast regions of space? From aliens to new planets, black holes, white holes, wormholes to even a tear in the fabric of space? Truly the universe is an exciting place and I for one want to explore it and uncover the mysteries it has created.
Space exploration is a better use of money than the military is. The government spends lots and lots of money on the military (in the billions), on getting better guns, better air forces, better weapons. It's a much better use of their money to explore what we don't know. It's part of our education, learning about things we don't know. We don't know what's out, millions of miles away. Why not reduce the military budget, just a little bit, and explore more? It wouldn't even cost as much to explore as it would spend on the military.
On the downside, lots of children are suffering from diseases. Some people are losing their shelters by too much rain or other natural disasters. These problems can't be solved by just a group of people. We have to solve the problems on our planet first before we explore other planets where no living organisms are living.