Alex Filippenko is a popular lecturer who knows how to engage a lay audience. Our Pauling Memorial Lecture series folks are more sophisticated than average, as Alex readily pointed out, so we might not have needed as many cosmetology vs. cosmology jokes, but those were the slides, a part of the script. Ironically, I was wondering if his hair was dyed (so dark), but Tara said professors weren't that vain. Or maybe they cultivate the gray look.
Cosmology is still in its infancy, it's probably safe to say, as is humanity, which isn't to say humans are guaranteed a long trajectory. During Q&A, Alex expressed his opinion that humans, broadly defined, are a rarity in the universe, even if microbial life maybe isn't. Their intelligence may not confer sufficient advantages to keep them in the game. Here we are, only about 160 million years into the homo sapien experience, and we're already giddy and teetering, devoting zillions to weapons of mass suicide (WMSs).
"Dark energy" is mostly a placeholder these days, as is "dark mass" (these two are not the same). Plain old Newtonian gravity isn't providing a satisfying explanation for the galactic clusters cohering, which is where dark matter comes in. Dark energy, in contrast, is repulsive (or repugnant -- more jokes), and is responsible (in a theoretical sense) for pushing the clusters apart.
The bulk of the lecture was about detecting supernovae of a particular chemistry (A-1 type) and using these as "standard candles" to register distance. The work is tedious, but software helps. Monitor a few thousand galaxies a night, superimposing successive frames, and find the deltas, the bright spots. Two teams were doing this work, which was productive, both for the competition (a sport) and for corroboration once the results started coming in. These results were surprising: the receding of galaxies appears to be speeding up, starting around 5 billion years ago. Before that, the expansion was slowing, or so measurements seem to show.
Dr. Filippenko has his visuals. He threw a bright red fake apple into the air numerous times, to illustrate points about gravity, expansion, contraction, Einstein's cosmological constant. The rubber band with the balls strewn along it simulated an expanding universe. He also had a small blue balloon to inflate. Much of the banter was "by the book", is what you will find in introductory textbooks on cosmology.
The very meaning of "the universe" seems to have broken down, now that we have talk of multiple universes, with some philosophers proposing communications between them. Partially overlapping universe scenarios might suggest eternal regenerativity to some minds. Each universe would be another way the game could be played, a set of realized possibilities. Such talk is purely speculative of course. Alex asserted his credentials as an experimentalist, not a theoretician.
Tara joined me for this outing, an expanding universe in her own right, an active thinker eager to learn from her world. I so wish for a better civilization for her and her peers.
My own universe seems to have settled into a combination of sorrow and love. I'm deeply fond of these people, awed by the suffering. Thinking of Paul Tillich and his "courage to be".
Good seeing Juliet and Jerome in the auditorium. Jerome went to middle school with Alex. Juliet was my contemporary at the International School in the Philippines.
