Why do we only see stars at night? Why are there more sunny days in the summer? Why does the moon seem to change shape? Why do the clouds move? Learn the answers to these questions and more in this question-and-answer series about the patterns we see in the sky.
ThriftBooks sells millions of used books at the lowest everyday prices. We personally assess every book's quality and offer rare, out-of-print treasures. We deliver the joy of reading in recyclable packaging with free standard shipping on US orders over $15. ThriftBooks.com. Read more. Spend less.