Welcome to the Virtual Reference Desk Learning Center. The Virtual Reference Desk (VRD) can help you find information and answers to your questions about school subjects, fascinating facts, research topics, and more! The Virtual Reference Desk can help you connect with experts by using the AskA tabs in the Learning Center. Use the tabs for FAQs (Frequently Asked Questions), archived questions (previously asked questions), and top sites to find resources selected by librarians and subject area specialists.

The purpose of NASA's Earth Observatory is to provide a freely-accessible publication on the Internet where the public can obtain new satellite imagery and scientific information about our home planet. The focus is on Earth's climate and environmental change. In particular, we hope our site is useful to public media and educators. Any and all materials published on the Earth Observatory are freely available for re-publication or re-use, except where copyright is indicated. We ask that NASA's Earth Observatory be given credit for its original materials.