On the 5th of July 2016, Juno successfully
arrived at Jupiter and inserted itself into a polar orbit. This means Juno has spent the last year gathering
data around the biggest planet in our solar system. So, what has it actually seen? Was it worth all the fuss of getting this
orbiter to Jupiter in the first place? Well take a look at a few of these breath-taking
pictures, and then you tell me. Of course though, Juno isn’t just an expensive
camera, and has been performing several different scientific experiments too, and the results
have completely changed the way we understand the solar system and Jupiter. So what has Juno been doing? It’s in a highly perpendicular orbit which
brushes over the planet at its closest approach, only 4,200km above Jupiter’s atmosphere;
the furthest point takes Juno out over 8.1 million km. Each orbit takes 53 days to complete, and
it will complete 12 orbits by the end of its mission in July 2018. At the time of making this video, Juno has
completed Perijove 6, or its 6th closest approach, so we’re about halfway through this mission. As Juno is in good health, it could be that
its mission is extended beyond 2018. One of the reasons Juno approaches so close
to the planet is to avoid Jupiter’s powerful radiation belt. There is a gap where the planet ends and the
radiation belt starts, and Juno exploits that. There was some concern that Juno would still
get a huge dose of radiation from the parts of the radiation belt it does hit, but the
radiation was actually ten times lower than expected in these parts, great for the health
of the probe. Remember, the previous Jupiter probe, Galileo,
was quickly rendered unusable by Jupiter’s radiation as its orbit went right through
the middle of the radiation belt, so mission planners were keen to avoid it as much as
possible. Another advantage of the tiny distance from
Juno to Jupiter at its closest approach is that we have been able to see Jupiter in unprecedented
detail! The first images of Jupiter’s poles in particular
took people’s breath away. Some even say that scientists would not have
even recognised the planet from these images; just no-one expected what they saw. What you are looking at here are many cyclones
around the South Pole. What is remarkable is that the planet looks
so different from what we are used to seeing on Jupiter, namely large bands. However, the contrast of the image has been
increased to see details; the natural eye would see something more like this. This image is also a mosaic of several images
in order to show daytime on all sides of the planet. The North Pole isn’t quite so clear, as
it’s in its winter and some parts of the pole are is constant night. Juno also has the capability to peer deep
into Jupiter’s atmosphere using a microwave radiometer, which was designed specifically
for this spacecraft. Using it, scientists were able to see the
amount of ammonia in the atmosphere. What they didn’t expect to see was this
band of ammonia around the equator, ammonia being orange in this image. This pillar drops down from the cloud tops
over 350km, the limit of what the MWR can see. Scientists are very puzzled by this, as they
expected to see an even distribution of ammonia throughout the planet. They thought the gases in the atmosphere would
just mix up, or at least stick to the band pattern of the planet, but these results are
far from that. This shows how variable the planet is under
the top layer of clouds. Previously, scientists had predicted that
Jupiter had a solid core, but using the gravity science instrument, it seems a lot hazier
or fuzzier than they would have anticipated. This could imply the core is not solid, has
dissolved, or doesn’t exist at all. It may be a while yet until we understand
the truth about this point, when all the microwave, radio wave and magnetic field data has been
combined to give a more complete picture. Speaking of the magnetic field, the results
from this also came as a surprise to scientists. In some places the magnetic field was stronger
than they expected, and some places were weaker. These patches also imply the magnetic field
is being generated above the core of the planet, as it is quite irregular, perhaps originating in the metallic hydrogen layer. The magnetic field, as we know, creates aurorae
and Juno has an infrared aurora mapper, giving us a view of Jupiter’s aurorae like we’ve
never seen before. The central band in this animation is the
main aurora, and this moving point to the left is caused by the closest of Jupiter’s
Galilean moons, Io. The tail of the point is the remnants of Io’s
orbital motion. The whites and greens from this image are
ions striking Jupiter’s ionosphere from space, and the reds could be ions coming from
the planet itself. If this is the case, it has never been observed
before now. Most of the data collecting takes place for
only a few hours per orbit as Juno whizzes by the planet. All the instruments collect as much as possible
during this time, including the camera. This remarkable video is a time-lapse of Juno
approaching the northern hemisphere and leaving again as it looks towards the southern hemisphere. And this image is collection of all the frames
that were used in the video. Approaching the planet, you can see the storms
around the North Pole, and gradually the view shifts to the mid latitudes. Zooming in on some of these shots, we can
see the classic swirls and patterns we expect on Jupiter, but having a really close look,
we can see these white specs. These specs are actually water or ammonia
ice clouds, as can be seen by the shadows they create. They are higher in the atmosphere than the
rest of the cloud layer, and although they look small, they are actually over 50km wide. Jupiter is just really big. Once you notice them once, you start to see
them everywhere. Due to the freezing cold temperatures at this
altitude where the clouds are, and because they are made of water ice, it could very well be snowing on Jupiter! Remarkably, we are still learning so much
about our giant neighbour. You might have thought that because it is
the closest and biggest gas giant, we would have a pretty good understanding of its mechanics. It seems with the arrival of Juno, however,
we still have a lot to learn, and there’s probably questions we don’t even know yet,
let alone answers. Thanks for watching! Your support means a great deal to me. I’m sorry for the hiatus, I’ve been doing
a lot of work for uni but I now have the summer off and I’m looking forward to getting some
videos out to you guys! If you don’t want to miss them, be sure
to subscribe, and if you want to see more like this then give it a thumbs up so I know! Thanks and see you next time.
