What do you see when you look at the moon? Probably not a slice of cheese; it may just seem like a big, dry rock to you. But is it? In 2008, researchers at Brown University determined that samples of lunar volcanic glass contain water. Scientists from other institutions, in both the U.S. and Japan, have studied unrelated igneous moon rock samples and found significant amounts of water. Why are these discoveries important? They provide additional data concerning the moon's formation and planets' acquisition of water [source: Taylor].
When considering the vast universe, this may seem like a small breakthrough, but that's how much of our knowledge of space has developed: incrementally. Scientists collect information over a period of time from observations, experiments, space probes and other sources, trying to piece it all together to advance understanding.
Very little of what we've learned about space has been obtained in a "Eureka!" moment, when, suddenly, an unknown is comprehended. Researchers have uncovered a tremendous amount of information about the universe, especially impressive since no human has personally visited most of it. There's still much to learn, however, from bits of data that can help us understand the answers to key mysteries. Here are 10 of those crucial cosmic questions, ranging from close to home to far, far afield.