Professor Dave again, let’s learn about Uranus.
As we move through the solar system, we are getting farther and farther away from the
sun, seemingly doubling the distance with each new planet.
Jupiter was around five astronomical units away from the sun, while Saturn was nearly ten.
Almost twenty astronomical units away from the sun lies the seventh planet, Uranus.
Just as Saturn, or Cronus, was the father of Jupiter, or Zeus, it was decided that the
trend should be continued, and when this planet was discovered in the 18th century, it was
given the name of the father of Cronus, which was Uranus, the primal god personifying the sky.
This planet is much smaller than Jupiter and Saturn, but it is still quite large compared
to the rest of the solar system, with a diameter around four times that of Earth’s.
The smaller size combined with the incredible distance explain why this planet was never
seen until the age of telescopes, as it is almost invisible to the naked eye.
Similar to the other gas giants, Uranus has an atmosphere rich in hydrogen, and also lots
of methane, and it is the methane that gives the planet its deep blue color.
Its interior is different from that of the larger gas giants, with no metallic hydrogen
to be found.
From assessing density, Uranus is thought to be a layer of hydrogen gas surrounding
a layer of water mixed with methane and ammonia, and with a core of iron and rock.
Uranus has a system of rings just like Saturn, with a very similar distribution, though not
quite as complex.
However, because they are much darker, they are not likely to be very icy, like Saturn’s rings.
Instead, they are more likely to be comprised of organic material.
Uranus also has an extensive system of moons, 27 of them to be exact, and five of them are large.
All of the moons are named after literary characters of William Shakespeare and Alexander
Pope, with the five big ones being Miranda, Ariel, Umbriel, Titania, and Oberon.
They form a system just like the moons of the other gas giants, and they are comprised
of ice and rock.
The smallest of these five moons, Miranda, has a bizarre patchwork appearance, broken
into distinct areas that are seemingly unrelated.
This suggests that the moon formed as the result of a collision between two separate
bodies that then merged to form one moon, leaving behind enormous cliffs twice the height
of Mount Everest.
One peculiar feature of Uranus is its extreme tilt, with its equatorial plane nearly perpendicular
to the plane of its orbit.
This means that one hemisphere gets daytime for half the year while the other is in perpetual
darkness, until the other half of the Uranian year, where they swap.
This is probably due to collision with a planetesimal early in the formation of the planet, and
the object that collided was smashed into the material that would become the moons.
And that wraps up a glimpse at the Uranus and the Uranian system, so let’s move forward
and round out the solar system.