Kind: captions
Language: en
in the
1970s it was meticulous observations
gathered by an
astronomer that forced scientists to
confront the idea of dark matter the
astronomer's name was Vera
reuin despite having Advanced degrees
for over a decade reuin had never been
able to collect her own
data astronomy had few women and many
observatories weren't
welcoming some officially did not allow
women but the national Observatory at
kit Peak had just recently
opened and accepted her
application she would return to Kit Peak
several times over her
career as she began to focus more on
Galaxies so this instrument behind me is
the 84 in telescope at kit Peak F Ruben
started using it in 1968 when she
started making measurements of the
Andromeda galaxy and looking at how
different regions in Andromeda were
moving Reuben wanted to check a common
assumption among astronomers about
galaxies the presumption was Stars near
the center of a galaxy would be orbiting
very rapidly and stars at the outside
would be going very
slowly that idea came from the way the
planets in our solar system orbit our
massive Sun
because the attractive force of the
Sun's gravity falls off with distance
the farther away from the sun a planet
orbits the slower its orbital
speed astronomers assumed the stars in a
galaxy would behave the same way but no
one had done the work to know for
sure partly it was a technical issue
which Ruben solved by teaming up with
instrument maker Kent Ford he had
developed a device that enhanced a
telescope's light
sensitivity making it possible to
finally see the faint stars on the far
edges of
galaxies and what they saw was
surprising they found that the regions
of Andromeda that were quite far out
were still rotating quite fast faster
than you would have expected by the
amount of light that was there it was a
strange
observation what was keeping those fast
moving outer stars from flying
off during the 1970s Ruben and Ford
along with other astronomers gathered
more and more data from more and more
galaxies almost none showed the speed of
orbiting Stars dropping as had been
expected still it would take years for
the astronomy Community to accept the
astonishing explanation that Reuben and
others
proposed that there was a vast amount of
hidden matter surrounding each Galaxy
gravitationally holding it
together aside from that effect it was
undetectable if you didn't have some
invisible mass in the Galaxy the Stars
would not be bound in this in this
orbits they would fly
out we now know that in every Galaxy we
study the stars at very large distances
are orbiting with very high velocities
and that tells us that there is a lot of
matter at very large distances from the
center so we see a lot of matter where
we don't see very much light and that
has led to the concept of dark matter
it's been a striking
transformation in the past 50 years
thanks to Vera Rubin and others dark
matter has become an essential
scientific building block at the
foundation of our understanding of the
universe