Everyone seemed to love the panel discussion on "Is time travel possible?", featuring Veritasium's Derek Muller as host; and Nima Arkani-Hamed, Daniel Harlow, Daniel Jafferis, and myself as panelists. We had a lot of fun with it, but also there's some pretty profound physics involved, in what one might have thought was a pretty flippant choice of topic. So without further ado, here it is:
(Back up to 7:55 if you want to hear all the introductions to the event at the beginning.)
After our panel there were two others on "What are the limits of Science" and "Is there life in the Universe", recorded in the same video. There were a lot of interesting people on these panels, although I don't think the conversations cohered quite as well as ours did, perhaps because they involved people from different disciplines.
In the second panel, Andrei Linde is a fun speaker, but I think he overplayed how much we currently know for sure about the early universe after inflation happened. There are a lot of mysteries between the time inflation ended (about seconds after the Big Bang by his reckoning) and the time of the Higgs Phase Transition (about seconds, which corresponds to the highest energy scale we can measure at the LHC). Between these times there are a lot of mysteries, like what process produced more matter than antimatter, as needed for any matter to exist today. I also wish he'd mentioned Cosmic Variance, a pretty obvious Limit on Science in his field.
Gary Ruvkin, the guy who thinks life on earth came from outer space was also kind of interesting. Apparently after about a billion years of nothing, life shows up on Earth and it's already pretty complicated. So maybe it came from elsewhere? The downside of this hypothesis, he said wittily, is that it "only buys you another 10 billion years" to evolve life (going back to the Big Bang). Since this is a physics and theology blog, I'll mention that even though I generally think that Darwinian evolution suffices to explain the evolution of complex life from simpler life, it does seem bewildering how something as complicated as the first cell might have arisen naturally, without a miracle. But just because I can't imagine it doesn't necessarily mean it couldn't have happened by some natural process. As a theist I am philosophically open to both supernatural and natural explanations, both of which are ultimately due to the Creator of all things.
That third panel should really have been: "Is there other life in the Universe", otherwise I think the question is pretty easy. This panel includes Jocelyn Bell Burnell who received a special Breakthrough prize this year for her revolutionary discovery of pulsars. Scandalously, the Nobel was given to her advisor but not to her; either because of sexism, or because of a bias against graduate students, or some combination thereof.
This seems like a good time to mention that, if I understand the history correctly, it was Daniel Jafferis' grad student Ping Gao who had the original idea to try to make a traversable wormhole in AdS/CFT. (Although as the 3rd person to join the collaboration, I can't speak to the exact division of labor between Ping and Dan.) Now the New Horizons prize was awarded for our lifetime of work so far, and not just for this one article, so I'm not saying that Ping should have been eligible for this particular prize. But I do think it's important for people to acknowledge junior collaborators, and not just assume the senior people did all the best work. So thanks Ping!