david rubenstein and most recently president of the university of maryland baltimore college friedman lebowski. our final evening program of the season will take place later this spring and will feature florence williams as she explores the science of off and the important role that nature plays in our everyday life. at this point i would like to thank david grinspoon not only for participating the series but for making the series possible. thanks to his generous gifts we are able to hold tonight's conversation and continue our public and engages in programming. before we get started i would like to take a moment to encourage you to complete and turn in your surveys. we learned a lot from your input and we use the information to develop our programming so thank you in advance. also please remember to turn off cell phones. now i would like to introduce our guests dr. david grinspoon today that is an honest-to-goodness astrobiologists, an award-winning science communicator and a prize-winning author. his latest book. >> we are are leaving this event for live coverage of the u.s. senate for a bri