20 November 2021 | New Scientist | 37“
cosmic evolution broadly right back
until that point, the big bang
“singularity” is singularly problematic.
It represents the point at which
general relativity’s equations become
plagued with ungovernable infinites,
and break down. In this sense, “the big
bang is understood as not a fact, but
a problem”, says cosmologist Daniele
Oriti at Ludwig Maximilians
University in Munich, Germany.
“It’s a pathology of our theories.”
With no clear explanation of what
the big bang was, we are pretty
hamstrung in explaining why it was.
There is no shortage of ideas: that
our observable universe is just one
of many budding off one another
in an eternally inflating multiverse
(see “Why is the universe just
right?”, page 41), for example, or that
a pre-existing universe contracted
to a small, but not infinitesimal, size,
before bouncing outwards again.
Oriti is developing an idea in which
the big bang singularity represents a
“phase change” where space and time,
and the rules of geometry that govern
our universe, emerged from some
non-geometric netherworld.
But in explaining how our
something sprung from something
else, these resolutions just raise the
question of why those other things
existed. Perhaps that is telling us
something about what it means
to seek the origins of everything in
the first place. The truly sublime
aspect of asking this question isn’t
so much in finding the answer, but
in the otherworldly journey it takes
our minds on. Joshua Howgego01
Features
As late as the 1940s, physicists
including Hermann Bondi, Thomas
Gold and Fred Hoyle were explaining
these observations in terms of an
eternal, steady state universe that
expanded through the continuous
creation of matter. Today, we can cross
this possibility off the list. “That’s not
a stable state for a universe that is
structured in the way we see ours is,”
says cosmologist Katie Mack at
North Carolina State University.
That is partly because it is hard to
square with the way gravity works, only
pulling inwards, not pushing outwards.
But it is mainly down to the discovery
of the cosmic microwave background
radiation in the 1960s. This all-pervasive
radiation was exactly what you would
expect to see if everything began as a
tiny, dense glob of matter and energy
that has since expanded and cooled to
become the universe we see.
Suddenly, the “why something
rather than nothing?” ball was firmly
in science’s court. What exactly
happened at the instant of the big
bang, now pinpointed to some
13.8 billion years ago?
These days, cosmologists don’t
automatically think of it as a point
when everything came into being from
nothing, says Mack. Indeed, while we
are confident we have got the story ofWhy is there something
rather than nothing?
N
O QUESTION is more sublime
than why there is a Universe:
why there is anything
rather than nothing,” philosopher
Derek Parfit once wrote.
Sublime it might be, but the
question has traditionally exercised
philosophers and theologians.
Creation myths, a feature of many
cultures, satisfied a deep-seated need
for meaning and narrative drive in
our existence (see “Why do we exist?”,
overleaf). Scientific thought, insofar
as it paid attention to such matters,
assumed the cosmos had always been
there in an eternal, unchanging state.
Then came the greatest scientific
revelation of the past century,
arguably of all time: what came
to be known as the big bang.
Its seeds were sown by Albert
Einstein with general relativity,
his theory of gravity, back in 1915,
and by Edwin Hubble and others
in the 1920s. Their astronomical
measurements showed that far-off
galaxies were receding from us, as
if the universe were expanding.