The cosmos is all that is or ever was or ever will be
that's a quote said by Carl Sagan in 1980.
Today as I look out upon the ocean it's shimmering depths as vast and blue as I
can imagine, I spots swimmers, a boat, a city gentle reminders that this body of
water is not just an inanimate mass of h2o molecules bound carelessly to each
other but it is a medium that life exists on around and within. So too does
the vastness of our cosmos exist not just for the stars and gas to play but
for us, it is our home and provides us with an endless source of mystery and
intrigue. How lucky are we that the universe is not simple to understand and
cannot be entirely known for what a boring reality that would be.
We've learned a few new things about the cosmos in recent years
in 2015 the LIGO experiment made the first detection of gravitational waves
it was from a pair of colliding black holes. It was an event that sent ripples
through the universe and through the astronomical community. We've been
wading ankle-deep in our discovery of the cosmos but the detection of
gravitational waves was our invitation to wade out
a little deeper. Before, all we could see out there were electromagnetic waves but
through immense precision, intelligence and dedication we have gained an
entirely new sense with which to discover. The detection of gravitational
waves also fundamentally changed our understanding of where we come from.
The cosmos is within us, we are star stuff, yes but that's not all. The cores of
stars are nuclear reactors fusing hydrogen into helium. We may be so lucky
as to receive a little bit of the waste heat
from the reaction on a sunny day at the beach. When a star has used up all of its
hydrogen fuel it may flare up and start to fuse atoms to other elements such
as lithium, carbon, nitrogen all the way through the periodic table until it's
core is iron. Stars that reach this point might collapse in a brilliant
supernova explosion casting their stardust out into interstellar space.
What's left behind might be a dense neutron star or a black hole. In 2017 the
LIGO experiment again detected gravitational waves but this time from
two colliding neutron stars. Astronomers all around the world pointed their
telescopes up to the same spot in the sky to watch and what they saw was a
flash, the light from which could be analysed to see that this collision had
created vast amounts of heavier elements like gold, platinum and uranium. So
violent neutron star collisions may be an essential part of our chemical origin.
But most of the atoms in our bodies don't come from stars at all
the majority of atoms in our bodies are hydrogen and the majority of hydrogen
atoms have never been inside a star. Hydrogen atoms are the combination of
protons and electrons that come together as the universe expanded and cooled in
the aftermath of the Big Bang. Small amounts of other atoms such as lithium
and helium were also created then 13.8 billion years ago at the birth of our
cosmos. All of these elements have been brought together by the flow of gravity
and time to form our planet, our oceans and us.
We are curious creatures who will continue to swim out deeper into the
cosmic ocean. As supernovae dust, neutron star collisions and as remnants of the Big Bang,
we are away for the cosmos to know itself.