The Solar System #9: Neptune

Neptune is an odd duck.

For one thing, it’s the furthest planet away from the sun but it’s actually warmer than its nearest neighbour, Uranus. Some scientists think it’s due to a difference in density, but others think it collided with a giant “super earth” at some point in the distant past and it’s still sitting there in the centre of the planet, radiating heat.

Not creepy at all.   

Neptune is a darker blue colour than Uranus (*giggle*) and has a blue spot - kind of like the red spot on Jupiter. Actually Neptune has some of the fastest winds in the solar system blowing at up to 900 kilometres per hour!

Early astronomers found it because of the weird orbit of Uranus (*giggle*). They correctly thought that it looked like something BIG was acting on it to make it less-than-circular. About 50 years after Uranus was discovered (*giggle*), astronomers found Neptune.

Neptune only has 14 moons (“only” - you see what this research project has done to me?). But one of them, Triton, is probably the weirdest moon out there. It’s so cold that it has nitrogen ICE geysers. NITROGEN ICE. That’s cold. Triton’s also got this weird terrain around the middle that astronomers genuinely call “cantaloupe terrain”. Take a look at the picture below and you’ll see why - it’s not unlike a rock mellon right?

Triton’s existence also lends significant weight to the “something massive crashed into this thing billions of years ago” theory. It completely ignores all laws of physics and relativity, orbiting Neptune backwards. This suggests it belonged to the super earth that got swallowed and was captured by Neptune’s gravity.  

But really… we don’t know. These two “ice” giants are largely a mystery.

Tomorrow: Trans Neptunian Objects!

Science Space is a not-for-profit organisation at the University of Wollongong. The work presented here was written by me as a part of a larger project spear-headed by my colleague Amanda Kruger.