With the first week of school at Bakersfield College now in the bag, the William M Thomas Planetarium is about to start its fall season of shows. The season starts Sept. 18 with “Black Holes: The Other Side of Infinity,” a favorite of audiences from 5 to 90+. Stellar mass black holes are thought to form when massive stars die and their core violently implodes on itself. A shock wave results from the sudden implosion of the core and that shock wave blasts the outer layers outward. The doors open at 7 p.m. and are locked when the show begins at 7:30 p.m.
My family recently went up to Sequoia National Park to attend some of the Dark Sky Festival activities that I wrote about in my previous column. The festival continues to grow. Last year about 500 people looked through the telescopes put out by the Kern Astronomical Society behind Wuksachi Lodge. This year about 750 visited the telescopes!
Jena Meinecke, Ph.D., a plasma physicists and junior research fellow at the University of Oxford in England, gave a great keynote talk at the festival about her work with the most powerful lasers in the world to simulate how very strong magnetic fields are created during extreme events like supernova explosions that happen when very massive stars die. She described the serendipitous discoveries she made when she got to “play around” blowing up other objects with the huge lasers. Now these are objects smaller than your pinky nail, not big objects of science fiction films, but she did find that the magnetic field interactions on the micro-scale are the same as what we observe with supernova remnants.
During the question-answer time at the end of her talk, Meinecke said she got a great start in physics at a California community college. It was there that she discovered her love of science. She started out as an art major in college because she didn't have a good experience with her high school physics class. However, a good community college physics teacher showed her that science can answer fundamental questions about the universe. She said no one should feel bad about going to a community college. (I smiled smugly at that.) When deciding on a career, her tip to college students is to ask themselves, “Would I do this job even if I wasn’t paid?”
If you missed going to the Dark Sky Festival, you still have a chance with the next best thing, the public star party at Panorama Park on Saturday. The Kern Astronomical Society will have their telescopes out to look at the moon, Jupiter, Saturn, and some star clusters. The moon will be a waxing gibbous, just a couple days past first quarter, and it will be between Saturn (on the left) and Jupiter (on the right) but closer to Saturn.
The first stars in the universe are thought to be extremely massive ones, more than twice as massive as the most massive ones existing today because the earliest stars would have been made of pristine material, just hydrogen and helium, without any of the heavier elements made in successive generations of stars. The heavier elements block more of the light generated from the star’s core and prevent the stars from becoming too massive.
The supermassive earliest stars would have gone supernova but the energies would have been so extreme that huge numbers of electrons and their antimatter partners, called positrons, would have been produced. Recall Einstein’s famous equation, E = mc^2? That means that matter can be created from energy if the energy is high enough. All those electrons-positrons would cause a runaway fusion that detonates a star before the core can form a black hole. The star truly blows itself up, leaving nothing behind.
This type of supernova, called a “pair-instability” supernova was just a theoretical idea until perhaps just recently. I say “perhaps” because it looks like a recently-discovered supernova might be our first observation of such a supernova. The supernova with the catchy name of “SN 2016iet” occurred in a galaxy almost a billion light years away. Spectra of the environment around the exploded star show the gas is pristine: it hadn’t changed much since the Big Bang. Observations of how the supernova’s light changed over time indicate the star was quite massive (perhaps up to 120 times the mass of the sun) but other features in the light are unlike any other supernova we’ve seen. The search is on for other examples!