I'm Jo Dunkley
and I'm here to tell you
about three amazing women astronomers
who, in the late 19th
and 20th Centuries,
faced down challenges many
of us would recognise today.
Despite the obstacles,
they each managed
to change the way
we understand the universe.
Astronomer Henrietta Swan Leavitt
joined Harvard College
Observatory in 1895.
She was part of an extraordinary
group of women
known as the Harvard Computers.
Their job was to classify stars
using photographic images.
As women, they weren't allowed
to operate the telescopes themselves
and were paid very little.
Leavitt studied stars that get
brighter and dimmer over time.
She discovered a pattern in 1908
now known as Leavitt's Law.
Which says that...
This means that just by measuring
the rate of pulsing,
which might be days or weeks,
and by seeing how bright
the star appears from Earth,
an astronomer can find out
how far away it is.
This was transformational.
Edwin Hubble used Leavitt's discovery
in the 1920s
to work out that smudges
of light in the sky
were in fact entire galaxies
far beyond our own.
The universe was much bigger
than we thought.
I have such admiration for Leavitt
because she was assigned
very mundane tasks in her job yet
still made this vital breakthrough.
Cecilia Payne-Gaposchkin also worked
at Harvard College Observatory
after Swan Leavitt.
In the early 1920s,
she used the latest learnings
about quantum physics
to come up with the idea
that stars are all made mainly
of hydrogen and helium gas.
Up until then, no one had known
what stars are made of.
They were thought to have similar
ingredients to our planet, Earth.
Payne-Gaposchkin said that stars are
much simpler than anyone thought.
However, the well-known astronomer
Henry Norris Russell
advised her to remove her idea
from her PhD thesis in 1925
as it went against
the current wisdom.
Just a few years later,
Payne-Gaposchkin
would be proved right.
She would later go on to become
the first female head of astronomy
at Harvard University.
I wonder if Payne-Gaposchkin
would have been discouraged
from her bold new idea
if she had been a man.
Luckily it didn't stop her
from achieving great things.
Vera Rubin was
an American astronomer.
She finished her studies in the 1950s
while juggling caring
for her young children,
often having to attend lectures
in the evenings.
Rubin wanted to study
how entire galaxies spin
and she became the first woman
allowed to use the
Palomar Observatory in California.
At the time, there was
no women's bathroom.
But undeterred, Rubin pasted a paper
skirt on the men's bathroom door
to create her own.
Rubin discovered
something surprising.
All of the galaxies she looked at
were spinning too fast,
as if something more massive
but completely invisible
was holding them together.
Rubin showed that
every galaxy is surrounded
by a huge halo
of invisible dark matter.
50 years later,
we still don't know what it is.
Rubin's story inspires me.
Her discovery is so important
to my current research,
and I relate to her as a mother
trying to balance doing science
with looking after young children.
It's not easy
but it's a fun challenge.
These women all made
great discoveries in astronomy,
and despite being little-known
throughout their lives,
their stories continue to inspire
women across the world.
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Thanks for watching.
