Celebrate Earth Science Week at the Harvard Museum of Natural History!  Learn about current research in Earth Science through hands-on activities led by graduate students in Harvard’s Department of Earth and Planetary Sciences. Why does the Earth have layers? How do we know Earth's temperature in the past? How do we find planets outside our solar system? How accurate is satellite measurement of gases in the atmosphere?  What are the impacts of aerosols on the climate? Try your hand at adding to our giant chalk timeline outside the museum.