Our planet, like the living organisms that inhabit it, is made up of many
different chemical elements, so neither could have formed if the chemical
elements had not been manufactured in the violent death throes of large stars
(in supernovae) or in the last dying days of other stars. The earliest stars may
have died within a billion years of the creation of the Universe. Since then,
billions upon billions of stars have died and scattered new elements into
interstellar space. The ¿ rst stars were born, like our Sun, from collapsing
clouds of gas within about 200 million years of the big bang. Today, there
may be more stars than there are grains of sand on all the beaches and deserts
of our Earth. And that takes us back to the beginning. Our Universe began as
a tiny, hot, expanding ball of something
popped out of nothingness like an
explosion about 13.7 billion years
ago. The explosion has continued ever
since, and we are part of the debris it
has created.
The story told in this course is our best
shot at explaining origins of all kinds.
Like all origin stories, it is far from
perfect and will change in the future. Important details, including the date
of the big bang, have been clari¿ ed in the last decade or two. Here are some
other possible areas in which the story may change. Cosmologists will keep
pushing back their understanding of the origins of the Universe. The holy
grail will be a theory explaining why the Universe popped out of nothing,
or perhaps what it popped out of. Cosmologists will try to understand “dark
matter” and “dark energy.” Biologists will acquire a better understanding of
the origins of life on Earth (and perhaps elsewhere).
Anthropologists will seek new evidence on the origins of our species. To do
this they will have to invest more time and energy in the archaeology of Africa
in the Paleolithic period and improve their understanding of the evolution of
symbolic language and collective learning. Genetic dating techniques will
allow us to track human migrations with much greater precision. We also
need an improved interdisciplinary understanding of complexity that can
illuminate our understanding both of stars and of modern human societies
and can tease out the many links between different types of complexity.
Trying to imagine the long,
drawn-out death of our
Universe suggests that we
may live in the most exciting
era of the Universe’s history.