Neptune is the 8th and the most distant planet in the solar system and is a mysterious dark world, because of it’s colossal distance from the Sun it is only ever been visited by the Voyager-2 spacecraft back in 1989 which captured the first close up images of the Neptunian system. Neptune’s atmosphere is mostly made up of hydrogen and helium but it’s beautiful blue color comes from methane and other components in the upper atmosphere which absorb the red light and reflect it as a magnificent vivid blue.
Neptune has mostly been studied from ground based telescopes which means the planet still holds many unanswered questions about it’s icy interior but because of the incredible Voyager-2 spacecraft and the data collected from the Earth scientists have been able to study many aspects of Neptune’s structure and composition giving them a greater understanding of what is inside of the mighty ice giant, so let’s jump into a science fiction spacesuit and dive directly into this strange world to see what lurks deep below Neptune’s mysterious clouds. Because this mission is impossible for any human being.
Let’s assume that we have been equipped with special science fiction spacesuits that will take us all the way to the planet’s core and protect us from devastating environment that Neptune has to offer such as frigid and scorching temperatures, deadly radiation, lack of oxygen and it’s colossal pressures. As we fall towards Neptune, we would have an incredible view of the planet’s immense storms raging below us, we would be descending at a similar speed to if we were falling towards the Earth as Neptune’s gravity is only 14% stronger than our own planet Earth. Because we are so far away from the Sun, very little light reaches this distant planet of the solar system, resembling a dim twilight back on Earth.
We would first fall through a high white cirrus clouds made of methane ice crystals at about 0.5 atmospheric pressure which is half the atmospheric pressure at sea level on Earth. At this altitude it is incredibly cold, dropping to below -200 degrees Celsius or -350 degrees Fahrenheit, around 30 miles down, we would enter into the ammonia and hydrogen sulphide cloud decks at about 5 atmospheres, here the clouds move faster than the speed of sound on Earth as Neptune experiences the fastest wind in the solar system which reach speeds of up to 1500 miles per hour, but because of our science fiction spacesuit let’s assume we are kept steady and continue on our descent.
Because of Neptune’s thick clouds and distance from the Sun, no light can penetrate this deep and we would find ourselves in a pitch black, cold, lonely environment with violent winds whipping past us. After falling for a long time we would be 100 miles into the Neptune, when huge flashes of lightning illuminate our dark surroundings, revealing towering white water ice clouds that are causing rumbling thunderstorms to occur.
As we pass through this cloud stage the pressure would increase to well above 50 atmospheres and the temperature would be around 26 degrees Celsius, using our hi-tech science fiction helmet we can now see what is around us but we would quickly realize that the cloud layers were the easy part of the adventure, as we emerge from the bottom of the water ice clouds the pressure would become intense and the temperature would drastically increase to above 1000 degrees Celsius.
After a very long time of sinking we would be around 4000 miles into the Neptune and within the planet’s mysterious mantle layer, here our suits would have to withstand pressures greater than 10,000 atmospheres and the increasing temperatures higher than 4000 degrees Celsius, this strange super-heated layer is composed of water, methane and ammonia ices that behaves as a hot dense fluid under immense pressure, because of these extreme pressures, carbon atoms might also crystallize and form diamonds.
As we descend ever closer towards Neptune’s core, these diamonds would rain down around us like glittering hailstones as they slowly sink slowly sink through the liquid mantle. After a long time of sinking through this thick region with pressures and temperatures continuing to drastically increase our adventure would come to an end, thousands of miles into the planet we would be standing on Neptune’s core, a surface which is roughly the same mass as Earth and made of rock, iron and exotic ices possibly with a layer of nestled diamonds. In this region we would be stranded, unable to travel further and unable to escape, we would be doomed to spend rest of our lives in a scorching environment with our science fiction suit having to withstand the temperatures of above 5000 degrees Celsius and pressures of above 7 million atmospheres.