In all the hubbub surrounding space exploration, it's easy to forget that we live on a pretty darn interesting planet in its own right. While it might not orbit a binary star or be made of diamond, the Earth is still more remarkable than any planet discovered by the Kepler mission. It sits in the habitable zone of a stable star. Its rotation is stabilized by an unusually-large moon. It has life!
If the Earth and Moon didn't exactly orbit the Sun as they do, there'd be no eclipses . Without those, our understanding of the Sun would be far worse than it is today. If the Earth didn't have deep surface oceans and numerous volcanoes, we wouldn't be able to understand how life could survive without sunlight. Without Antarctica, we wouldn't understand patterns of life in an extreme cold which borders on that of space. In the absence of rivers and deltas and lakes and basins, how could we hope to identify these features on the surface of Mars or Enceladus or Venus?
Simply put, if the Earth wasn't as remarkably diverse as it is, our science would be more limited and our understanding of the Universe even less compete. So, take the time today to think about the incredible planet we live on, the amazing things it has enabled us to do, and the delicate relationship we have with it. Happy Earth Day!