From the time we learn to talk, whenever we discover something new, the first thing we want to do is tell someone about it! It shouldn't be any different just because we're adults. The drive to learn and share should only increase as we get older.
We learn by doing. We've all got something to contribute. I write about whatever I find engaging at the moment.
One of my favorite quotes, by Astronaut Mike Massimino, about why we explore and discover:
"In the shuttle era, NASA got caught up making nuts-and-bolts justifications about why we go to space when the real answer is just because. We go because we go. We do it because we do it. Because human beings have always done it. It's the reason we first left the caves and poked our heads around the next corner to try to see what the world was about. "