Michael Joner is an observational research astronomer. He has spent much of the past 25 years working at the telescope. Mike has been an invited visiting astronomer at observatories around the world, where he has spent many months working hundreds of nights under some of the most beautiful skies that can be found anywhere on Earth. Mike has made use of data secured from remote, robotic, and space-based telescopes, and has even flown an observing mission aboard the Kuiper Airborne Observatory operated by NASA. Mike has been a contributing author on well over a hundred astronomical presentations and refereed journal articles.

In this installment of the "How Do You Know That?" presentations, Professor Joner will discuss the history, background concepts, and various applications of the astronomical distance ladder. Topics to be covered include parallax, variable stars, supernovae, and redshifts. Once you have seen this presentation, you will not only know how astronomical distances are measured but you will recognize the reliability of different methods and what you should believe when you read a news article about a new and fantastic discovery.

TIME: 10:30 AM Sunday Talks 2