Every single thing we encounter on Earth exists because, at
one point, its atoms were processed through stars. This week Sarah Pearson took
us through a tour of the origin of the elements, from hydrogen and helium,
through every element in our bodies and the world around us. The real stars of
tonight's lecture were supernovae,
the beautiful
explosions
that both produce and distribute elements throughout the universe.
Shortly after the Big Bang, the universe consisted almost
entirely of hydrogen and helium. At this point, we had a long way to go before
enough elements were produced to give rise to the rich chemistry that governs
life here on Earth. As Sarah explained, within the first stars, and in every
star since then, nuclear fusion smashed together hydrogen and helium to form
increasingly heavier, and more complicated elements. However, these elements
would still be trapped within the cores of stars if it not were for a weird
quirk of physics. As Sarah showed, once iron is produced within stars, they
enters its death throws; quickly collapsing then suddenly exploding with
tremendous energy....
Sarah showed images observations of supernova remnants, the
hot gas left over after a supernova explosion. This gas expands and mixes with
its surroundings, carrying elements produced inside the star with it. Over
time, after many explosions, these elements mix throughout a galaxy, eventually
ending up inside new stars where the cycle continues.
After the talk, we discussed recent updates to the upcoming James Webb Space Telescope (JWST). Lauren
Corlies gave an overview of the instrumentation of the JWST, the replacement to
the Hubble Space Telescope. Andrew Emerick talked about the science goals of this
upcoming mission, from observing exoplanets in the Milky Way to the first stars
and galaxies formed near the beginning of the Universe.
-- Andrew Emerick (graduate student)
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