Published on March 6th, 2012 | by Yellow Magpie5
Planet Neptune: The Mysterious Azure-Blue
An Azure-Blue world, planet Neptune is the fourth largest planet in the Solar System. It is also the farthest away from our Sun. Yet, this freezing world contains many oddities that remain for now puzzlingly unexplained.
Planet Neptune orbits our Sun from a distance of 30.1 astronomical units. Highlighting just how vast these distances are, it takes Neptune just under 165 Earth-years to complete one orbit. At over 49,500 kilometres (30,900 miles) in width, it takes just over 16 hours for the planet to complete one day.
Planet Neptune is an an icy giant with unbelievably cold temperatures. The average temperature on the surface of Neptune is minus 201 degrees Celsius (minus 330 degrees Fahrenheit).
Planet Neptune’s Interior
Planet Neptune’s internal structure is very similar to Uranus. It is differentiated into four layers. The outermost is the upper atmosphere which consists of clouds, the next layer in is the atmosphere which is composed of helium, hydrogen and methane, all in gaseous form.
The second innermost layer is the mantle which consists of water, ammonia and methane ices. The innermost layer is the core which is thought to be comprised of silicates and nickel-iron.
At its outermost layers the atmosphere of planet Neptune is comprised of 19 per cent helium and up to 80 per cent hydrogen with traces of methane also being present.
Planet Neptune’s atmosphere has many clouds at differing altitudes and Voyager 2 has captured some remarkable images.
One of the most startling aspects of planet Neptune’s atmosphere is the heat of its thermosphere. Measuring 426 degrees Celsius (800 degrees Fahrenheit), it is a far cry from the Earth’s which can reach 2,500 degrees Celsius (4,500 degrees Fahrenheit) but is highly unusual for a planet so far from the Sun.
Scientists maintain that either gravitational waves emanating from the planet’s interior or an atmospheric interaction in the magnetic field must be responsible for the abnormal heating.
Fragile Ring System
In 1968, a team of scientists discovered that planet Neptune had a planetary ring system. It was not until Voyager 2’s fly-by in 1989 that a proper image of the rings was taken.
Recent evidence by observatories on Earth has shown that these rings are much more unstable than those found in other planets. It is now believed that some come and go over short periods of time, as little as a century in some cases.
The climate of planet Neptune is very different from its sister planet, Uranus. Huge storm systems hurl winds at near supersonic speeds. Winds at the equatorial regions speed around the planet at 400 metres per second. While they only travel at 250 metres per second in the polar regions.
One of planet Neptune’s most famous features is The Great Dark Spot. Sometimes measuring roughly the size of the Earth, The Great Dark Spot is a name given to enormous anticyclonic storms.These storms are relatively short-lived in comparison to the long term feature that is Jupiter’s Great Red Spot.
The Great Dark Spot holds the record for the fastest winds found in the Solar System which were recorded at 2,400 kilometres (1,500 miles) per hour.
Unknown Heat Source
Planet Neptune is internally heated by an as of yet unknown mechanism. Despite being the farthest planet away from the Sun in the Solar System, it produces the fastest winds and radiates out more than two and a half times the energy that it receives.
Several ideas have been put forward to explain this heating phenomenon with gravity waves and radioactive decay from deep within the planet’s core heating planet Neptune being proposed.
It is thought that planet Neptune formed out of a gas disc that was left over after the formation of the Sun.
Originally much closer to the Sun, Neptune and the other giant planets are thought to have migrated to where they currently reside.
Planet Neptune has 13 known moons including one major moon, Triton. Yellow Magpie will soon be taking a closer look at Triton.
Voyager And Beyond
The last time a spacecraft visited planet Neptune was through Voyager 2 in 1989. So far there are no definite plans for a spacecraft to visit the planet in the immediate future.
Highly Recommended Reading
Check out Yellow Magpie’s Uranus: The Coldest Ice Giant for more insight into the largest planet in the Solar System.
You may also wish to take a gander at The Solar System And Beyond: A Guide To The Cosmos.
Cosmos is a highly recommended book. It contains large, full-page pictures of the asteroids and writing on the subject by the highly competent author, Giles Sparrow.
For people living in Ireland or the United Kingdom, you can access: Cosmos from here.
For those who live in Canada, you can obtain: Cosmos here.
For Germany: Cosmos.
For France: Cosmos.