Why is space travel not necessary?

Space Travel is very expensive and it also has a very negative effect on the environment, but it helps mankind understand much more about everything in the universe which satisfies our curiOSity. In the aspect of understanding our universe space travel is very necessary.

But how does it really help us? If a major comet the size of a mountain comes along (which happens every 100,000,000 years) and we, because of space travel, can stop it, well then space travel has been a very necessary thing indeed. If that doesn't happen, I'm not sure if you can class space travel as a necessity. Why should people starve in the world when so much money is spent on space travel? You can't eat rockets...

It's a matter of opinion if space travel is a necessity or not. I for one think our understanding of the universe is important in several aspects, such as understanding how unique we are and how unique life is and I hope we can come to appreciate it more then we do today.

In addition I believe that the moon landings cost about five percent of the tax money during those years (if you know the correct numbers please tell me) Ask yourself if you think that money was well spent and if that was necessary.