Hi guys and welcome to BrainSnacks! My
name is Clara and in this channel I
would like to share my fascination about
science and technology. The first episode
is about the discovery of Neptune. There
are just a few places on earth from
where a planet was discovered. Recently I
found out that I used to live close to
the discovery location of Neptune.
Neptune was discovered in 1846 by the
German astronomer Johann Galle
after the French mathematician Urbain
Le Verrier calculated where to find it.
Let's see what is left of the observatory
today. Now standing close to the exact
location, where Johann Galle looked at the
night sky through his telescope. Right
behind me that's the Jewish Museum and
this building already existed at the
time of the Berlin observatory.
Unfortunately of the observatory itself
there's nothing left today except for an
information panel with the ground plan
and explaining that on the wall of the
observatory there used to be a reference
benchmark for the sea level. This is how
the star observatory looked at the time
when Neptune was discovered. Here we have
the astronomer Johann Galle and the
mathematician Urbain Le Verrier. But I think
that everyone should know that from here
a planet was discovered.
We should put a flag here, but wait
didn't I bring one?
But before we find out how this actually
happened here are some facts about the
planet. Neptune is the farthest known
planet from the Sun in our solar system.
It is the fourth largest planet by
diameter after Uranus, Saturn and Jupiter.
Neptune is 17 times as massive as Earth
and 58 Earth volumes could fit in it.
Its average distance from the Sun is
4.5 million kilometres. One Neptune day
is 16.1 hours and one Neptune year, so
the time that Neptune needs for a whole
orbit around the Sun, is one hundred
sixty four point eight years on earth.
This is NASA's spacecraft Voyager 2, the
only spacecraft that visited Neptune and
to close pictures of it and its
satellites. Neptune has 14 known moons.
Triton, its biggest, moon has some very
interesting characteristics. Its orbit
goes in the opposite direction of the
orbit of its planet. This is called a
retrograde orbit. Moreover the orbit is
inclined relative to Neptune's equator
which suggests that Triton did not form in
the orbit around Neptune, but was
gravitationally captured by it. But how
did the mathematician in the astronomer
discover the planet? Well, long before
they did, already other astronomers like
Galileo Galilei had seen Neptune through
a telescope, but they didn't identify it
as a planet. The actual discovery started
with another planet: Uranus. In 1846 it
was known that Uranus, the closest planet
Neptune, had irregularities in its orbit
around the Sun. The theory to explain
this of Urbain Le Verroer was that there had to
be another planet farther out in the
solar system that influenced Uranus
gravitationally. With the data of Uranus'
orbit, he calculated where to find this
unknown planet. Then he informed Johann
Galle Berlin, who discovered Neptune
within one degree of its theoretically
calculated position.
This makes Neptune a planet that first
has been theoretically predicted and
then had been actually discovered. Isn't
that cool?
Thank you very much for watching and if
you liked it, please click on the Neptunian
subscribe button. This was Clara from
BrainSnacks and I hope to see you again
next time! Bye Bye!
