22 | New Scientist | 25 April 2020
I
DON’T know about you,
but for me, every week of
2020 has felt extremely long,
especially since the coronavirus
pandemic has gotten under way.
As I am not an essential worker,
I am currently spending most of
my time at home. I try to focus on
my work on both science and the
philosophy of science, but then I
inevitably check the news. Each
update seems to make the week
drag on for longer and longer.
The reel of bad news may feel
like it is never-ending, but one
of the ways that I have tried to
keep things in perspective is by
thinking about the different
timescales on which things
occur in the universe.
As an early universe cosmologist,
I know, for example, that cosmic
inflation happened in a fraction
of a second. Cosmic inflation of
space-time, the fabric of our
universe, is one of the first things
that ever happened. This was a
period in which space-time, like
the number of cases of covid-19
in many areas when it first got off
the ground, grew exponentially.
The more space-time there was,
the more space-time grew.
The rate of space-time
expansion during inflation was
so quick that it grew faster than
the speed of light. This might be
surprising to hear because we are
all so used to the idea that nothing
goes faster than the speed of light.
This is the case for things that
live inside space-time, such as
people, planets and spaceships,
but there is no such limit on
space-time itself.
We currently believe that
inflation lasted from around
10-36 to 10-33 seconds after the big
bang. Not only did space-time
grow faster than the speed of
light, but this period of expansion
was extremely short. A week of
this outbreak is essentially aneternity in comparison.
So perhaps cosmic inflation
isn’t the best way to maintain
perspective on human timescales,
but what about stellar astrophysics
instead? Stars like our sun have
lifetimes of about 10 billion years,
which is very close to the current
age of the universe. This scale is
difficult for humans to fully
comprehend.
Interesting things can
happen towards the end of stars’
lives. They initially shine because
they are “burning” hydrogen –
essentially an atomic reaction
that fuses hydrogen atoms
together to produce helium.
This releases energy, some ofwhich we observe as photons,
particles of light.
In the case of the sun, this
process has roughly another
5 billion years left to go. If you,
like me, have been socially
isolating for around five weeks,
this means that the sun still has
about 50 billion of your lockdown
periods so far left before it
reaches the end of its life.
Eventually, the sun will start
fusing helium into carbon. This
process will begin in our sun
when it has about 100 million
years of life left, which is about a
billion times as long as the period
that we have been in isolation for
so far. These processes certainly
put our wait into perspective.
Yet such prolonged timescales
aren’t the only ones that are
relevant to stellar evolution.
Although helium to carbon
conversion will continue forat least 100 million years, the
transition to this process will
begin with a helium flash that
will take place in just a
few minutes.
We have been stuck in
lockdown for a lot longer than
this, of course, but at the very
least we can say that we won’t be
in social isolation for the time
that it takes for the sun to start
making carbon!
The helium flash isn’t the
only stellar process that can take
just minutes. When the sun finally
dies, it will leave behind a remnant
known as a white dwarf. This is
a very dense object made of
hydrogen, helium and carbon,
and when white dwarfs are the by-
product of stars at least 10 times
more massive than the sun,
they contain a good amount
of oxygen too.
These white dwarfs can
experience instabilities that will
be familiar to people who have
been to the beach: just as an
ocean’s waves are partly the result
of gravity, white dwarfs experience
waves caused by gravity in their
interiors. Such waves then cause
pulsations in the brightness of the
white dwarfs, and these can be
around two weeks long.
So one way to think about
how long you have spent in
physical isolation is to compare
it with this phenomenon: so far,
you have probably been trying to
avoid contact with people outside
your household for only a couple
of white dwarf pulsations.
It may not be your first
instinct to use these references,
of course. But if you are losing
your sense of time or feel as
though this outbreak is messing
up your natural biorhythms,
it may help to try and reframe
the timescales involved in terms
of cosmic phenomena. It is
helping me, anyway. ❚This column appears
monthly. Up next week:
Graham Lawton“ You’ve probably
been trying to avoid
people outside of
your household for
a couple of white
dwarf pulsations”When time drags The coronavirus pandemic is making life feel
very slow, but observing timescales across the universe can bring
us some comfort, writes Chanda Prescod-WeinsteinField notes from space-time
What I’m reading
I am rereading parts of
Helen Longino’s Science
As Social Knowledge:
Values and objectivity
in scientific inquiry.What I’m watching
My friends and I are
holding Zoom parties
to watch a reality show
called The Bachelor
Presents: Listen to
your heart.What I’m working on
I have been spending a lot
of time learning about the
controversy concerning
the unexplained surplus
of gamma radiation at the
centre of the Milky Way.Chanda’s week
Chanda Prescod-Weinstein
is an assistant professor of
physics and astronomy, and
a core faculty member in
women’s studies at the
University of New Hampshire.
Her research in theoretical
physics focuses on cosmology,
neutron stars and particles
beyond the standard modelViews Columnist