Neptune by Chris Verbeek
Introduction: Neptune is the outermost planet in our solar system. The diameter of Neptune is 49,528
kilometers which means it’s about 4 times the size of earth. Its distance from Earth is 4.3 billion kilometers and
the distance it is from the sun is 4.54 billion km. Its rotational period is 17.24 hours and to rotate around the sun
it takes 165 years. Neptune's mass is 102.4x10^24 kilograms which is roughly 17 times larger than earths and its
density is 1,638 kg/m3. Neptune’s orbital eccentricity is 0.0097. Neptune’s atmosphere consists of clouds that
relate closely to our sirrus clouds. Neptune has something called “The Great Dark” spot which can be compared
to the Jupiter's famous “Great Red Spot. This spot on Neptune is roughly the size of the earth. The magnetic field
of Neptune is very similar to that of Uranus’.
History: Neptune was first observed by Galle and d'Arrest on September 23rd 1846 very near to the locations
independently predicted by Adams and Le Verrier from calculations based on the observed positions of Jupiter,
Saturn and Uranus. This march Neptune entered the Aquarius constellation
Theories of Formation: There was a theory that said that Neptune was created in the outer regions of our solar
system. This was disproven when it was found out that the matter density in the outer regions was too low to
possibly make up this huge body. The alternative formation concept is that Neptune formed close to the sun
where the matter density would’ve been higher and once formed it moved to its current orbit.
Moons and Rings: Neptune has a total of 13 moons. Just 17 days after the discovery of Neptune, William
Lassell discovered Triton which is Neptune's biggest moon with a diameter of 2,706.8 km and the 7th biggest
moon in our solar system. It is the only large moon in our solar system with a retrograde orbit (orbit in the
opposite direction to its planet's rotation.) This moon is covered with ice and is one of few moons in the solar
system known to be geologically active. 5 inner moons were also discovered when voyager 2 flew past Neptune
in 1989. Neptune's rings consist of ice particles coated with silicates or carbon-based material. The planet has 3
major rings known as Adams Ring, Le Verrier Ring, and the Galle Ring. First signs of these rings were
discovered in 1968 by a team led by Edward Guinan.
Structure, Chemical Composition and Surface Conditions: Scientists believe that Neptune is made up chiefly
of hydrogen, helium, water, and silicates. Thick clouds cover Neptune's surface. Its interior begins with a region
of heavily compressed gases. Deep in the interior, these gases blend into a liquid layer that surrounds the planet's
central core of rock and ice. Neptune is covered with layers of clouds which can blow up to 2,100 km/hour which
make them the fastest in the solar system. The clouds further away from the planet contain methane and the inner
darker clouds are believed to be composed of mainly hydrogen sulfide. The atmosphere is composed of 85%
Hydrogen, 13% Helium and 2% Methane. The average temperature of Neptune is around -200 degrees Celsius
while the core of Neptune sits around 7000 degrees Celsius
Exploration of Neptune: Since Neptune is so far away from us, Voyager 2 is the only spacecraft to have
explored it. Since this was the last major planet the spacecraft could visit, it was decided to make a close flyby of
the moon Triton. The spacecraft verified the existence of a magnetic field surrounding the planet and discovered
that the field was offset from the centre and tilted Voyager 2 also discovered 6 new moons and it discovered that
there were 3 rings instead of just one.
• Neptune is the fourth largest planet
• In 1989 Voyager 2 became the only spacecraft to have visited Neptune.
• Of all the planets in the Solar System, Neptune has the strongest wind flow.
• Neptune's moon, Triton, is slowly getting closer to it. It is believed that finally, the moon will get so
close that it will get torn apart by Neptune's gravity and, possibly, form rings more spectacular than
• Neptune's moon, Triton has the coldest temperatures measured in the Solar System, about -230°c.
• On July 12, 2011, Neptune will have completed the first full orbit since its discovery in 1846.
• Pluto's orbit is so eccentric that it sometimes crosses the orbit of Neptune making Neptune the most
distant planet from the Sun for a few years