Space can be…weird.. Very weird. So weird in fact that astronomers are still being shocked
by new and peculiar discoveries. One of the most peculiar planets in our solar system,
Neptune contains many mysteries yet to be uncovered. As the most distant planet from
Earth, Neptune lies at the edge of the observable universe.
The first time Neptune was seen by human eyes was through a state-of-the-art telescope back
in eighteen forty six. The swirling surface and rich blue color earned the name Neptune
after the Roman god of the sea. Previously it’s existence had been discovered mathematically
by astronomers after they noticed disturbances in the orbit of planet Uranus.
Neptune has seldom been explored by astronomers. The first and only close up of this mysterious
planet was over thirty years ago when the Voyager 2 spacecraft flew by near enough to
photograph it. No craft has ever been back since. Much of our knowledge about this colossal
giant is in the dark, just like Neptune’s own dark and brutally cold weather.
What lies beneath Neptune’s clouds? Will humanity ever be able to study it up close?
And what will we find when we do?
You’re watching Matter and today we’re looking into what NASA found on Neptune’s
surface.
FIrst identified as a planet in the night sky in 1846, Neptune is one of the two ice
giants in our solar system along with Uranus. It is the eighth planet in the solar system
and sits at a distance of nearly two point eight billion miles away.
This is thirty times further from the sun than the Earth sits and where sunlight takes
just about eight minutes to get to us but it takes over four hours to reach the surface
of Neptune.
Neptune is also massive and measures nearly four times as wide as the Earth. Its atmosphere
is primarily composed of hydrogen, helium, and methane gas clouds that make up a large
portion of Neptune’s size.
The thick gas clouds turn to a slurry of dense icy fluid made up of water, methane ice, and
ammonia on top of a dense core made up of solid ice and rock.
Its orbit is also gigantic, one year in Neptune time is equal to one hundred and sixty five
years here. Neptune has only just completed its first full orbit around the sun since
its discovery in two thousand and eleven.
Voyager two has brought back a large amount of the data that astronomers have about Neptune
and much of their understanding of the planet comes from its fly-by.
Scientists were finally able to look closer at Neptune's composition and there have been
pushes to send another spacecraft back to collect more information.
Voyager 2 Neptune
Neptune is 30 times further from the sun than the Earth.
It is composed of thick gaseous clouds made up of hydrogen, helium, and methane above
a dense icy fluid made up of water, methane ice and ammonia.
Voyager 2 has brought back a large amount of the information that astronomers know about
Neptune. Storms on Neptune
In two thousand eleven as astronomers looked out to Neptune they noticed a massive storm
raging on the surface. This storm was big enough to cover half of the entire United
States.
This storm caused temperatures to plummet to one hundred and twenty eight degrees Celsius
below zero with winds blowing at a staggering speed.
But this is not the only storm that has been seen on Neptune and is not even close to the
largest. Neptune is known for having dark spots on various points on its surface. In
nineteen eighty nine astronomers found what they dubbed the great dark spot.
This was a massive vortex storm on Neptune's surface that measures almost wider than the
entire Earth at more than eleven thousand kilometers wide.
This storm had the fastest wind ever recorded on any planet in our solar system raging at
nearly one thousand five hundred kilometers an hour.
Neptune Hurricanes
Neptune Storm
Neptune’s Dark Spot
Neptune is known for massive storms that rage on its surface.
Some are known as dark spots that are vortex storms with the largest measuring nearly the
width of the Earth.
The storms on Neptune have the fastest winds ever recorded in the solar system at 1500
kilometers per hour.
Rings of Neptune
When most people hear about planetary rings, the first thoughts jump straight to Saturn.
And while Saturn does have beautiful planetary rings, it is not the only planet to have this
amazing feature.
Neptune has a total of five rings that encircle the planet. Astronomers believe that these
rings are relatively young and were most likely created long after the planet and solar system
were formed.
The five rings, starting with the closest to the planet’s surface, are called Galle,
Le Verrier, Lassell, Arago, and Adams.
These five rings vary greatly in their size and their orbit with the closest ring located
about forty two thousand kilometers from Neptune’s center and the furthest ring is located nearly
sixty three thousand kilometers from the center of the planet.
Adams ring comes in at the thinnest of Neptune's rings measuring only fifty kilometers at its
widest and fifteen kilometers at its narrowest. Lassell is the widest of Neptune’s rings
with the majority of it measuring four thousand kilometers wide.
Neptune has five rings that vary in size and distance from the planet’s center.
Astronomers believe that they are relatively young and were formed well after the solar
system was formed. Triton
Its planetary rings are not the only thing orbiting around Neptune. Neptune is also home
to fourteen moons.
The largest and most interesting of these moons is named Triton after a lesser god of
the sea in Greek mythology.
One of the first things astronomers noticed about Triton was its orbit. It orbits Neptune
in the direction opposite of the planet’s rotation. This caught the eye of astronomers
because it is the only moon in the entire solar system that exhibits this type of orbit.
Titon is thought to have been floating through the solar system independently until it got
too close to Neptune and got caught up in the gravitational field.
Astronomers want to study Triton closer up, they have already found incredible features
on Triton’s surface including geysers spewing icy material up to eight kilometers above
the surface.
Triton is the largest of Neptune’s moons and has caught the most interest from scientists.
It orbits the planet opposite to the direction of rotation.
Neptune is hot?
Voyager two picked up information that confirmed that Neptune is hotter than its closer partner,
Uranus.
This piqued the interest of astronomers because Neptune is an ice giant receiving very little
heat from the sun and even though it is further from the sun than Uranus it is still hotter.
Astronomers theorized that something must be heating the planet up near its core and
that an internal heat source is responsible for warming the entire planet.
But what could this internal heat source be? The answer may come as quite a surprise, but
first Neptune has some other interesting features such as its magnetic field that may play a
role in this as well. Neptune is hotter than its cousin ice giant
Uranus even though it is further from the sun.
There must be something generating heat internally in the planet.
Neptune's magnetic field, heat and pressure
Neptune has a strange magnetic field in that it is much weaker than the one produced by
the Earth. It comes in at only around one third the strength of Earth’s magnetic field.
In addition to being fairly weak, the magnetic field of Neptune is not in alignment with
its rotational axis. In fact, the magnetic poles of Neptune are tilted about forty seven
degrees off of its rotational axis.
Astronomers aren’t sure what the ramifications this has for the conditions on Neptune and
there is still debate as to what caused this tilting. It could have been a major impact
that threw off the magnetic field, or it could be due to something else happening within
the planet itself.
In contrast to this weak magnetic field, Neptune’s core remains extremely dense and hot. Neptune’s
core itself can reach temperatures over seven thousand degrees Celsius. Quite a bit hotter
compared to the Earth’s core which reaches temperatures just over five thousand degrees
Celsius.
The pressure is also incredibly high near the solid core of Neptune due to the massive
gaseous atmosphere and icey liquid layer beneath it.
Due to the intense pressures and super hot temperatures, some scientists believe that
these have led to something that sounds straight out of science fiction. Down in the depths
of Neptune, there may be diamond rain.
Neptune’s magnetic field is weak, only ⅓ the strength of Earth's.
It is also tilted off the rotational axis by 47 degrees.
The core of Neptune is extremely hot and dense.
The core is super hot measuring over 7000 degrees C while Earth’s core only reaches
just over 5000 degrees C.
Is it raining diamonds on Neptune?
Astronomers know that there is incredibly high pressure and heat beneath the upper atmosphere
of Neptune. And due to this immense pressure, the hydrogen gas that exists in Neptune gets
compressed to the point that it forms a metallic liquid version of hydrogen.
As the hydrogen atoms are being compressed, the methane that makes up Neptune's atmosphere
begins to break down and the bonds holding its hydrogen atoms to its carbon atom dissolve.
This leaves behind a free carbon atom and once it is free, stray carbon atoms begin
to bind to one another. As the carbon atoms bond together to form larger molecules, the
incredible pressure causes the chunks of bound carbon atoms to form into diamonds.
Once these diamonds are formed they fall to the planet creating massive sheets of diamonds
that could add to the gravitational energies of the core.
If this theory is true, it could be the reason Neptune is warmer than the closer ice giant
Uranus. The formation of diamonds in the methane clouds and subsequent fall of those diamonds
would create a large amount of heat through friction and increased gravitational energies.
The combination of pressure and heat can lead to methane breaking down and the bonds holding
its hydrogen atoms to the carbon atoms dissolve.
Once the carbon is free it can bond with other carbons and form diamonds under the intense
pressure and heat.
If it is raining diamonds in Neptune, it could be the reason why Neptune is as hot as it
is.
Layers of diamond would not only create frictional force but it would also add to the gravitational
energy surrounding the core. Outro
Unfortunately astronomers will not be able to know for sure what is happening on Neptune
and why the planet is producing so much additional heat itself until they are able to send another
well-equipped craft to get a closer look at this massive giant lurking near the far out
in our solar system.
Do you find Neptune as fascinating as we do? What other planets do you think have weird
things going on?
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