Varieties of Time Travel

My kids have been reading lots of books over the break, including an adventure series that involves time travel. Knowing vaguely that dad is a theoretical physicist, they asked me how time travel works. 1. Can one change history by influencing past events? OR 2. Is there only one timeline that cannot be altered, even …

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To Edinburgh and Back

I had a terrific visit to Scotland last week.  The graduate students in the Institute of Evolutionary Biology at the University of Edinburgh invited me to speak there.  Thanks especially to Manon Ragonnet and Sam Lewis for organizing and hosting my visit. It seems a bit extravagant to fly overseas for a one-hour lecture.  But …

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