Winners United Kingdom
10-12 years old: Ice plumes at the south pole of Enceladus
Author: Bryony Few
I have decided to pick Enceladus plumes as the most interesting Cassini project. I picked this because of the unique contrast between Earth and Enceladus. The exciting concept of a icy, underground ocean is something we believe should be investigated further. It is unheard of, for a planet so distant to earth to be so similar. Maybe even to the extent of them both having the rarity of life? Like earth the moon is covered with a blanket of ocean, but in the case of Enceladus the water is frozen. The surface is silky smooth in some areas and bright white all over, thus making it highly reflective. So reflective in fact, that it is the most reflective body in the solar system! This also means it is extremely cold, because it reflects the sun light away making it -201 degrees Celsius.
What caused the water to freeze? What was it like before? Did life exist, or indeed does it still beneath the layers of ice? These are questions that we would like answered and we believe studying the plumes may be the key.
Enceladus is one of the 62 moons of Saturn and is only 314 miles in diameter, meaning it would fit within the length of the United Kingdom.
Before the Cassini project little was known about Enceladus and it wasn't until 2005 that the Enceladus plumes were discovered. They are geysers they spray icy particles and water vapour, released from the ocean below its surface. Also, they powerful enough to generate an enormous halo of fine ice dust around Enceladus, which supplies material to one of Saturn's rings- the E ring. The substance shoots out at about 800 miles per hour (400m/s) and forms a plume that extends hundreds of miles into space.
The E ring is mostly made of ice droplets, but Cassini also detected silica nano grains, which can only be generated where liquid water and rock interact at temperatures above 90 degrees celsius. This points to hydrothermal vents deep beneath Enceladus' icy shell. These maybe similar to the hydrothermal vents that be found on earth.
We think the possibility of life outside of earth is much more interesting and a better use of money than the other options.
Titans lakes may be interesting but would provide us with less scientific knowledge than Enceladus could provide. Equally, while investigating Saturn's hexagon may give us more information on the bizarre cloud pattern and the churning storm at its centre, this will not help us answer a more pressing scientific issue- is there life outside of earth?
To conclude, I feel the project Cassini should focus on is investigating Enceladus' plumes. The beauty of the planet and its icy surface can be seen from the photos taken by the Cassini probe, these photos only give us a glimpse of the wonders that may lie below its surface.
13-15 years old: Ice plumes at the south pole of Enceladus
Author: Nilusha Perera
All three possibilities of exploration are fascinating, Titan has the possibility of being the closest known body with properties similar to the Earth, and investigating Saturn’s hexagon could lead to a better understanding of weather on other planets, but I believe that the Enceladus’ Plumes are the most worth investigating.
Enceladus is extremely interesting in itself, the fact that it has an ocean below its surface, suggesting some form of heat source that could possibly be a hydrothermal vent, and this causes the water vapour to break through the surface. These exploding geysers have the appearance of tiger stripes, if we image this area, we can find out why. We would also be able to find out if there if a possibility of life.
A key reason for why I chose this was because of the possibility of life on this planet, because if we are able to find examples of other life forms that do not live on earth, we might be able to deduce how life is created in general, not just how we were created. I think this is very important as this gives us a sense of purpose, and the majority of people would have wondered why we exist. Finding out how we were made could help us to answer these questions. It is thought that for life we need a liquid medium, and as Enceladus has water there is a genuine possibility of some form of life existing on this planet, even though light cannot reach this planets ocean, we know that light is not essential to life. If Cassini is to image this planet, we could potentially widen our knowledge about life forms and even find a new type!
In addition to this, the fact that Enceladus has a hydrothermal vent in itself is important, they could help us learn a lot more about deep sea creatures and how they survive. Studying the vents, which are the cause of the plumes could help us to determine how the earliest forms of life functioned. We could have the chance to learn more about extremophiles, and these could benefit us as they may have chemical properties that make them valuable, this could revolutionise our industry.
Finally, the geysers of Enceladus lead us to ask many questions, such as how a moon so cold, around -200 degrees Celsius, could have active geological features, such as the hydrothermal vents that could have possibly been the cause of this. If this is the case, it could mean that moons like Enceladus could in fact have warm cores, and this would mean that we have a lot to learn about how celestial bodies are formed.
To conclude, I believe that we should image Enceladus and its plumes, find out how they occur, and see if this affects our knowledge of the formation of the universe. If this is not enough, it also provides the exciting possibility of extra-terrestrial life, and could aid us in learning more about life on Earth.
13-15 years old: The lakes of Titan
Author: Wiktoria Dzienia
Why I chose Titan’s Lakes:
I have chosen Titan’s Lakes as my project because I find it fascinating how there could be life on other planets/moons. For me, it is a very exciting experience, and I hope that you enjoy my essay.
Titan was first ever discovered in 1655, by a Dutch astronomer named Christiaan Huygens. A fascinating fact is that the Cassini-Huygens mission has also been named after him. Titan is Saturn’s largest moon, and scientists have recently discovered that there are lakes on Titan that consist of liquid Methane and Ethane that are in the form of gas here on Earth. However, NASA had suspected that there might be lakes on Saturn’s moon long before this discovery. In the Solar System, Titan is the only moon that has a dense atmosphere (that consists primarily of nitrogen), and the only planet/moon in space where people have found some signs of liquid (other than Earth of course). Titan is about 50% larger than the Moon, but since it is primarily composed of water ice and rocky material, it is only 80% more massive. This moon is the second largest in the Solar System. Its climate includes wind and rain – it creates surface features similar to those on Earth, such as rivers, lakes, seas and deltas. Seasonal weather patterns shape Titan's surface similarly to Earth. Its Methane cycle is analogous to Earth’s Water Cycle, however at a much lower temperature of about -179 °C.
The first lake to be found on Titan was named Ontario Lacus (it is in Titan’s south polar region). On the 22nd July 2006, the Cassini mission took a radar image of the northern latitude (near the pole) which showed a lot of very smooth and quite large patches that were dotted around the surface, suspected to be liquid. The Cassini scientists suspect that rainfall and liquids feed the lakes from underground. Some lakes are thought to dry and fill up again throughout the period of 30 years. This is caused by the seasonal cycle on Saturn and Titan. However, the overall idea of how the depression hosting the lakes came about in the first place is poorly understood as the idea is very fresh. Cassini has also discovered that there might be bubbles of nitrogen in Titan’s Lakes.
Titan’s Lakes are an exciting discovery showing that there are a lot more thing to yet find out and investigate. Who knows, there might even be life on Titan. This subject is very inspiring and fascinating because scientists don't know what they will find, it makes it even more attractive. We don’t know what the future will bring, and all the other moons/planets can offer more unexpected discoveries.
13-15 years old: The hexagon at Saturn's north pole
Author: Blaise Cloran
For years the mysterious, northern hexagon located on Saturn has puzzled scientists. Its questions have been pondered on but never answered, this is why I am basing my essay on target three, because there is so much room for possibility. By building up knowledge on this strange phenomenon we can not only investigate into solar storms but Saturn itself and how it relates to its celestial cousins.
The Cassini images have already helped us construct a better understanding of the anomaly, yet there is still confusion within the topic of colour change. In 2012, when the region was photographed by the Cassini wide-angle camera it appeared to be blue, but when the spacecraft passed over it again in 2016 it seemed to have changed to gold. This strange shift was believed to be related to the season changes and the length of Saturn’s years, the hue alteration could be due to the increased production of photochemical hazes in Saturn’s atmosphere as the pole approaches a season change. These pictures are extremely scientifically valuable because they supply so much information in two single sources of data. The photos can help us form conclusions on season change and how it relates to the year or day length on a planet, with these statistics we can then look into atmospheric properties and how that links to life on a different planet.
Furthermore, the hexagonal cloud pattern, rotates with a period of 10h 39m 24s, the same period as Saturn's radio emissions from its interior. Yet the hexagon does not shift in longitude like other clouds in the visible atmosphere. By researching into this it can again help us form answers on Saturn’s sky and exactly how it relates to our own atmosphere.
Due to other Cassini images, the hexagon is seen to contain a vortex, which could explain the unusual storms occurring and how long they have been going on for. The vortex also links to the idea that the hexagon was formed by the steep latitudinal gradient in the speed of the atmospheric winds. This scientific research will add to the studies of the planet’s collisions, which play a huge role in the ring’s waves and wakes that influence Saturn’s moons and what happens on the planet itself.
I believe that Saturn’s hexagon North Pole is the most scientifically valuable because it provides us with so many responses that create a chain reaction to answering theories about this gas giant. The planet is so diverse and holds so many different and interesting qualities that it can help us discover more about our solar atmosphere, which is the only way we can ever advance in inhabiting on a different world and due to the long Saturn year we don’t have many chances to observe these changes. It’s the only planet with a strange on going storm inside a six-sided jet stream and that is why we have to grasp this opportunity to open doors for space travel.
16-18 years old: Ice plumes at the south pole of Enceladus
Author: Daniel Marcus Corazzi
Does life exist beyond Earth? This is one of the most fundamental questions we can ask. I believe that pointing Cassini’s cameras back at one of Saturn’s moons, Enceladus, would provide us with one of the best opportunities to date to answer this question. Life requires water, heat, organic material and long-term stability. By studying Enceladus further we will be able to discover if it has all these crucial components, and thus determine whether it could harbour life.
In 2005, interest grew in Enceladus when Cassini detected interference in Saturn’s gravitational field. One explanation for this was that Enceladus could be larger than it appeared, which suggested the possibility of an atmosphere surrounding the moon, as well as something residing beneath its icy surface.
At the time scientists were also looking for an explanation for Saturn’s E-Ring, which is composed of small, icy particles, because it appeared that the material in this ring was replaced frequently. On Cassini’s third fly-by, which was much closer than pervious visits, 4 “tiger stripes” along the South Pole were photographed. In addition, jets ejecting icy particles and vapour from beneath the surface were observed. On a later fly-by, the material was analysed, and was found to contain about 1% salt, slightly less than the oceans on Earth. The only way to achieve these high concentrations is to have a large body of water, one of the necessities for life, under the icy surface. A large ocean of this type would also mean the conditions under the surface are stable, which is another requirement for life to exist.
The jets also contained silica particles, which can be produced through interactions of rock with water in warm conditions. It was then suggested that there may be hydrothermal vents on the ocean floor, meaning heat is also present on Enceladus. Since life exists on hydrothermal vents on Earth, it is possible that the same thing could be replicated on Enceladus. Organic hydrocarbons have also been detected in the jets.
If Cassini were to return to Enceladus, it would be able to further analyse the material ejected from the geysers to try and detect other organic molecules. It would also be able to attempt to detect Hydrogen, a key element that can be harnessed by small organisms. If Hydrogen is present on this moon, it is possible that organisms could use it as a source of energy; they would produce methane as a result of this process. Hydrogen has not been detected so far, however turning Cassini’s attention back to Enceladus would mean we would be able to search for it, along with other signs that life could exist on this moon.
Although the other targets are highly interesting, I think Enceladus is the best choice because it provides the best chance of discovering life beyond Earth. In my view this is one of the most important pursuits in science today, and therefore Enceladus would be the best target for Cassini.
16-18 years old: The hexagon at Saturn's north pole
Author: Andrew Ng
I believe that of the three targets, an attempt to study the hexagon at Saturn’s North Pole is the most appropriate, as the least is known about the enigmatic hexagon.
On earth, weather conditions typically last for weeks at most, and even this is by no means a common occurrence. However, it is fascinating that the storm on Saturn measuring 13,800km across, larger than the size of the Earth, can exist for decades or even centuries. This immediately gives rise to the questions asked by many scientists: ‘How has it remained stable? What fuels it for so long?’ Moreover, another, arguably even more intriguing aspect of the hurricane, is its shape. A distinct hexagon can be made out in most photos of Saturn’s North Pole, and no one has been able to definitively answer the question of how it stably maintains this shape over such long periods of time.
Various theories have been proposed to explain this phenomenon, which cannot be found anywhere else in the solar system. One theory holds that the hexagon is a result of drastically different wind speeds that cause an area of turbulent flow, with a number of vortices being formed. These then interact until they reach an equilibrium where they are evenly spaced apart. This only occurs on Saturn’s North Pole because the viscosity and speed difference have to be within a certain range; on Saturn’s South Pole, for example, Hubble observed vortices and a hurricane with a colossal eye but no hexagon. Another theory asserts that it is due to a series of spiralling vortices which have not been observed, but by imposing certain conditions on the jetstream, including being slow and shallow, scientists were nevertheless able to accurately simulate the behaviour of the hurricane.
According to Kevin Baines, atmospheric expert and member of Cassini's visual and infrared mapping spectrometer team at NASA's Jet Propulsion Laboratory, ""Once we understand its dynamical nature, this long-lived, deep-seated polar hexagon may give us a clue to the true rotation rate of the deep atmosphere and perhaps the interior,"" Gaining insight into the pure fluid mechanics of the gases, without being subject to terrestrial influences, apart from being an alluring topic of research in itself will also help us understand our own planet, for example the hexagon’s jet stream keeping photochemical smog out of the interior has been likened to the way the ozone hole over Antarctica can’t be replaced because ozone is prevented from entering by the strong winds.
With the start of Saturn's northern spring in August 2009, sunlight has begun to bathe the planet's northern hemisphere, illuminating the previously dark north pole. This should make an attempt to study it more fruitful and useful to the scientific community compared to previous years. It is therefore that I believe now is the time for Cassini to turn its eyes on the hexagon.