|Grade||Target 1: Enceladus||Target 2: Titan's Lakes||Target 3: Saturn's Hexagon|
|5-6||Reece Steidle||Naren Krishnan||Alexia de Costa|
|7-8||Matthew Zoerb, Benjamin Lambright and Nicholas Nautiyal||Jay Chakraborti||Vishakha Rath|
|9-12||Ken Cummings||Zade Akras and Vikash Modi||Shaunak Dabir|
Mount Nittany Middle School
State College, Pennsylvania
Teacher: Rose Snyder
"Of the three choices, Enceladus' Plumes is the most inspiring. This caught my eye because it reminds me of Yellowstone National Park. The plumes might have similar characteristics to Earth's geysers. I identified three reasons that Enceladus is the best target. First, the plumes are powerful enough to break out of the atmosphere because they travel about 800 mph. Second, there are hotspots under the ocean that cause the plumes. Earth also has underwater thermal vents, which indicates another similarity to Earth. Last, there is a liquid ocean and water is essential for life to exist.
Imagine the geysers at Yellowstone National Park, but thousands of times stronger, such that they can breach the atmosphere. Take this, and move it to ice-covered moon. That helps me imagine Enceladus' plumes. Just the fact that the snowy geysers can puncture the atmosphere is amazing. The plumes are expelled at around 800 miles per hour. The geysers supply Saturn's E Ring with ice particles and gasses. The heat vents cause the water and ice to be pushed upward at such high speeds that the geysers can break out of Enceladus' atmosphere.
The plumes would not exist without heat vents. Bacteria prefer a warm habitat like the vents in Earth's oceans, so if we could send out a probe it might find some living organisms similar to the the life forms near Earth's ocean vents. We know there are heat vents because scientists have found nano-particles called silica nanograins in Saturn's E Ring. Silica nanograins are created when water and rock are in contact at over 90 degrees Celsius. Also, heat causes water to rise, like the vents cause the water to rise and be expelled from the ocean in the form of plumes.
Another water feature of Enceladus is the liquid ocean under its crust. Enceladus' ocean is salt water, similar to Earth's oceans. Everything needs water to live. We know of very few, if any, other planets or moons with liquid water. If there is water, that makes it all the more likely that there could be life. In addition, there is the possibility that with enough work, we could have temporary colonies on the surface. We might be able to desalinate the water, making it potable, much as we have done on Earth.
Any one of these reasons alone would make me want to send out an exploration mission, but together they make Target 1 the best choice. There is a chance that Enceladus harbors life. Even if it is only bacteria, that would be a huge advance in Exobiology. This moon has more similarities to Earth than many other planets, including thermal vents under its crust, salt-water oceans, and plumes. These attributes point to the possibility of life on this ice-moon. The exploration of Enceladus could be the next giant leap for mankind."
The Academy for Science and Design
Nashua, New Hampshire
Teacher: Kevin Harbison
"The concept of life in outer space has intrigued and excited the minds of many. For centuries, we have theorized about life outside of Earth. Discovering life in outer space could open doors for science, leading us to places we have never ventured. It could answer questions about how life operates in low gravity, how organisms may function with different structures and the different applications of genetic information. Our group has finally decided that the Enceladus Plumes are the leading candidate for the next search for extraterrestrial life. Our basis of judgement was the ability to harbor life. This includes whether the location accommodated and contained liquid water, a stable environment, an energy source, and certain chemicals required for life.
To sustain life, an environment must hold liquid water. There is definite evidence that proves that there is water on Enceladus. That evidence comes in the form of silica nanograins. These microparticles only form in liquid water and an environment whose temperatures exceed 90 degrees (19 degrees F). They were found in the E ring, which derives a majority of it's material from the Enceladus Plumes. As well as proving that there is liquid water on Enceladus, we also know that Enceladus is geothermally active from the swaths of new land on it's surface. This creates a theoretically stable environment. Organisms would be living under 19-25 miles of ice and approximately 6 miles underwater in order to get the heat from the near-center of the moon. Not only does Enceladus have the requirements for water, an energy source, and a stable environment, but it's Plumes also contain chemicals required for a sustainable environment such as nitrogen, hydrocarbons, carbon dioxide, and methane.
The discovery of life on Enceladus would massively propel science and technology. If extraterrestrial life were present, we would be able to observe how basic lifeforms counteract the issues of prolonged existence in habitats with low gravity. We could also learn other ways in which life functions genetically and how it affects the Laws of Evolution. Evolution states that all creatures on the planet came from the same organism, which is why all organisms use DNA. If creatures that could not have inherited a DNA from Earth also use it, it suggests that either we got our genetic system from the same source or that the DNA/RNA system is the only system that can carry, execute, and replicate genetic information. Finding life away from Earth would yield tremendous scientific results and benefit future space explorations.
Life is a miraculous and fascinating phenomenon. It is crucial for the Cassini mission to look for any chance of extraterrestrial life in our solar system. We must take advantage of the ideal location that the Cassini probe is in, to provide imperative information that would otherwise take years to reach. That information would be put to use for future missions to Mars. We believe the Cassini mission to Enceladus will answer one of nature's greatest secrets and further our understanding of the universe."
Yellow Wood Academy
Mercer Island, Washington
Teacher: Gerald Mbara
"The Cassini Mission to Saturn revealed several important discoveries. The one I believe to hold the most potential is the observation of the plumes of Enceladus. Enceladus is a small moon of Saturn with a constantly shifting ice surface 30-40 kilometers thick, a subterranean global ocean 10 kilometers deep, an internal heat source, and a rocky core with a radius of 202-212 kilometers. Enceladus' icy crust is broken by geysers spewing water vapor, carbon dioxide, silica nanograins, methane, and an array of volatile gases. The plumes are evidence of possible hydrothermal activity, and this could be an indication of microbial life.
In 2010 Russel et al. theorized that life on Earth came from hydrothermal vents in the ocean from a process called serpentinization. Serpentinization is the "chemical binding of water and silicate rock". This forms porous rock and produces heat. At the time serpentinization would have occurred on Earth, the ocean was acidic (~pH 6). Serpentinite vents release alkaline fluids which interacts with ocean water, creating a natural pH gradient, from basic to acidic, and then precipitates as a porous mineral. The pores provide natural compartmentalization, serving as an abiotic semipermeable membrane. Like in cells, this separates an alkaline interior from an acidic exterior. This is the building block for chemiosmosis, the movement of protons across a concentration gradient, through a semipermeable membrane. Cells harness energy from the movement of protons to perform respiration.
Unlike our ocean when life was first formed, the ocean of Enceladus is projected to be extremely basic (~pH 11-12). This means that there is no natural pH gradient for chemiosmosis to build off of. This could still allow for serpentinization because over time the release of alkaline fluids raises the pH of water. If serpentinization has been occurring for what could be millions of years, a high pH is plausible. Moreover, there is evidence of serpentinization in our modern, slightly basic ocean (~pH 8.1), showing that this process can occur in an alkaline environment like Enceladus. Serpentinization on Enceladus could explain the internal heat source, the high pH, and traces of silica, carbon dioxide, and methane in the geysers.
Enceladus has an intense environment that very few known organisms could survive. Single-celled organisms of the
domain Archaea are some of the few known creatures able to live in such extreme conditions, without photosynthesis or oxygen. Archaea lack a nucleus and organelles, and can use carbon dioxide, hydrogen, and methane as energy sources, which serpentinization provides.
Even with our understanding of serpentinization, how life was formed on our planet is still a mystery. We know that it likely occurred in the deep ocean with the formation of organisms similar to Archaea. Enceladus has more potential for life than many other cosmic bodies in our solar system, and because of its environment, it seems that Enceladus' organisms could be similar to those of Earth millions of years ago. A closer look at Enceladus' ocean could be the key to unlocking the origin of life on Earth."
Target: Titan's Lakes
Medea Creek Middle School
Oak Park, California
Teacher: Michael O'Hagan
"The lakes on Titan, Saturn's biggest moon, are an oddity worth researching. Titan is the only alien planetary body in the solar system that has them! Unlike Earth where the lakes are made of water, Titan's lakes are composed of hydrocarbons like methane and ethane. They also may include some other components we have not detected in their depths. Because of Titan's subzero temperatures, these hydrocarbons which are normally gases on Earth are liquid on Titan.
One surprising fact is that Ligeia Mare, one of Titan's largest lakes, is completely composed of methane. NASA should explore the reasons for this unique body of liquid. Scientists expected the composition to be pretty close to 50% methane and 50% ethane, but these predictions were not even close. The ethane may have been transported out in an underground river or evaporated. This will require more research and brainpower into evaluating Titan's lakes and unlocking their secrets.
Scientists should also explore Target 2 because the placement of these lakes is odd. The majority of the lakes are in the northern and southern polar regions. No one really why the lakes are only in the polar regions, but it could be because of temperature. Perhaps there were lakes closer to the equator of Titan which have evaporated due to a warmer temperature, leaving Titan with some intriguing polar lakes.
Scientists have not fully explored this theory, but it is another reason Target 2 is the best target to conduct further research. Scientists have found another strange thing about these lakes. Almost all of the lakes are found near the north pole. Researchers hypothesize that this may be due to Saturn's oblong orbit around the sun. Because of this, Titan is 12% closer to the sun in the southern summer than its northern summer. This means that summers in the northern hemisphere are long and moderate while in the southern hemisphere they are short and intense. This leads to an accumulation of methane in Titan's northern hemisphere and lots evaporated in the southern hemisphere. This process on Saturn's abnormal moon is very similar to Earth's Milankovitch cycles. These cycles cause long-term climate change and Earth's ice ages. This potential similarity to Earth could uncover an amazing new discovery about either Earth or Titan.
Titan's lakes should be our astronomical scientists' first priority because of their hydrocarbon compositions, their polar region concentration, and the effect of the oblong orbit on their formations. These peculiar lakes spark curiosity in many of our greatest minds. Titan's strange coincidences and abnormalities should promote more research so we can further understand this Earth-like moon of Saturn's."
McCullough Jr High School
The Woodlands, Texas
Teacher: Janene Fowler
"This is Cassini's home stretch. Launched in 1997, it will celebrate its 20th birthday with a bang! With these last couple images NASA has a decision to make. What should it further explore? Saturn's moons? Saturn? With Cassini burning through the atmosphere in September the answer must come quick.
I think that NASA should certainly try to uncover more information on Titan's Lakes or Target 2. Liquids are essential to life. We spend our journeys through space looking for one certain liquid: water. Fly-by probes have discovered information that lead us to believe that under the frozen surface of places like Titan there can be oceans filled to the brim with liquid water like a lake with the icy top. But there is another type of ocean on Titan. Methane filled liquid hydrocarbon lakes. The methane finds itself right at home in Titan's chilling -290 degrees F and follows something similar to the water cycle you learned in second grade. At -260 degrees F the methane evaporates and at -295 degrees F it freezes. This allows it to make a methane cycle and it makes methane clouds, lakes, and rain.
If there is water on Titan that means that there is both oxygen and hydrogen. There is already methane and even if there are traces of nitrogen then something amazing could take place on Saturn's largest moon. In 1953, Stanley Miller was the first person to ever synthesize amino acids. He did this using hydrogen, water, methane, and ammonia. He passed voltage through it and it eventually made the acids. This could simply be replicated in nature by use of lightning since it has been found that Titan does have clouds even visible to the naked eye in the picture shown in Target 2. The amino acids could then go on to form proteins and if they bond with DNA or RNA then there could be life on the second biggest moon in the solar system.
Cassini-Huygens has been exploring Saturn for thirteen years and Huygens itself explored Titan, but we still have not solved all of the mysteries. If we go deeper we could find almost anything from water to aliens, but in the end, nobody knows for sure. So NASA has to find out."
Gates Mills, Ohio
Teacher: Chris Harrow
"Water is generally considered the benchmark for life. However, this norm is misleading. Liquid, not water, is imperative for life; scientists postulate that life needs a medium that can bring molecules close enough to interact while still allowing them to move. Liquid is the only stage of matter that satisfies both these requirements, and while water's polarity, liquid temperature range, and solubility make it especially useful, other liquids can be capable of sustaining life as well. Titan, Saturn's largest moon, is the only known celestial body beyond Earth with liquid lakes on its surface. Titan's lakes are the optimal target for study with the potential to reshape our understanding of life and its necessities altogether.
Thanks to the Huygens probe of the Cassini-Huygens mission, we know that Titan is remarkably Earth-like. It has a dense atmosphere more comparable to that of Earth than any other planet or moon in our solar system. Additionally, Titan experiences seasonal rains, which produce wet patches and lakes that are visible in Cassini's images. Titan also is home to water. However, at 90 Kelvin, the water on Titan's surface is rock-hard. Instead, Titan's precipitation and lakes are composed of liquid methane.
Titan's methane lakes present a unique opportunity in our galactic search for life. Methane life is unlike anything humans have ever seen. Chemical engineers and astronomers from Cornell University hypothesize that methane-based, oxygen-free beings on Titan could host completely different cell structures than those understood to date. Most cell structures on Earth are held together by phospholipid bilayers. However, methane-based cell membranes, referred to as "azotosomes," would be held together by the polarity of nitrogen groups. While Titan's low temperature could be a problem in the development of life, the presence of argon 40 isotopes in its atmosphere suggest that Titan has an active core, meaning it could still be warm enough for methanogenic life reactions. Moreover, researchers at the NASA Ames Research Center support this hypothesis, referencing the potential for life to adapt to the low temperature and solubility of organic compounds in liquid methane. Further study of Titan is necessary to confirm these premises. Finding life on Titan would be monumental, and discoveries on Titan could change the way we define and search for life altogether.
In our great search for extraterrestrial life, it's important to consider every possibility. While liquid water, like that of Earth, is certainly a strong indicator of potential life, liquid methane deserves ample study and observation as well. We will never know if life can exist without water unless we study other fluid samples, and the possibility of a completely new life form existing is fascinating. Studying Titan's hydrocarbon lakes can allow us to determine if water truly is the only liquid suitable for life. Even finding nothing on Titan would further our understanding of life, allowing us to specify and narrow our criteria for life's requirements. The extraordinary opportunity to enhance our understanding of life prompts the need for further study of Titan's methane lakes."
Target: Saturn's Hexagon
Queen of Apostles School
Teacher: Mrs. de Siles
"I chose Target 3 because I believe that studying Saturn's Hexagon would be a thrilling endeavor. It is a mystery that needs to be solved. Why Saturn? Because of the amazing atmospheric structure of this gas giant. Specifically, the planet's 20,000 mile wide strange hexagon-shaped storm - the width of two Earths - rotates at almost exactly the same rate as Saturn spins on its axis. At the north pole, the storm extends at least 46 miles below the giant planet's visible cloud top with winds raging close to 200 mph. The largest recorded wind system is 2,200 miles wide, twice the size of the largest hurricane recorded on Earth.
Hurricanes on Earth usually last for about a week, but the hurricane on Saturn has been in existence for probably decades or even centuries. What is even more intriguing is at its center is a polar cyclone.
So why has the storm taken the shape of a hexagon? Is it being shaped by stronger wind forces within and closer to the center of the storm? Is there conclusive evidence of winds beneath the jet stream, similar to our own arctic jet stream, going eastward around the pole at cloud level and being forced into a shape by other winds at lower levels? Could the geometric shape therefore be the result of the winds beneath the jet stream jostling and directing the air current into the observed hexagonal shape?
One also wonders why such a distinctly shaped storm developed in the north pole but not in the opposite south pole. Are the conditions at the south pole not favorable to support the formation of a similar geometric shape there? Well, it appears that the south pole has an interesting atmospheric feature too but not as mysterious as the distinct one in the north pole. The south pole has a polar vortex with a dark "eye". The size of the "eye" is about two thirds the diameter of the Earth.
We do not know how long Saturn's Hexagon storm in the north pole will last but by studying the movement of the hexagon and any patterns of change, it's possible that we can learn more and perhaps have a better understanding about the exact influence of the winds hidden under the stormy clouds in the upper atmosphere. This continued observation will certainly give us a better idea of the forces that shape this intriguing and one-of-a-kind geometric structure in outer space.
2017 will be Cassini's final year of exploration and what better way to end its journey of discovery than with a fiery plunge into Saturn. Target 3 is perfect for further scientific study because of the timing of the event and the impending potential to discover exponentially more about the true nature of the forces at work in this uniquely shaped storm. Clearly something exceptional is going on here and there are many intriguing questions that need to be answered related and relative to Saturn's turbulent north."
Plainview Old Bethpage Middle School
Plainview, New York
Teacher: Joseph Morello
"Have you ever played this game where you gaze up at the clouds and try to imagine which animal each passing cloud depicts? Look, I think that looks like an elephant. But my friend may think that it looks like a dragon! We can conjure up different shapes because the clouds we see on Earth form no regular or fixed shape. However, what if I told you that there are clouds in our solar system that have worked together to maintain a perfect hexagon since we discovered them in 1981? You may be surprised and so were the scientists reviewing data from NASA's Voyager. This was no game anymore and indeed, they had discovered a hexagonal cloud formation surrounding Saturn's North Pole, a phenomenon that intrigues scientists even today.
Saturn's hexagon is nothing like any cloud system seen on Earth and defies our notion of clouds, making it an attractive target for further investigation. Earthly clouds are aimlessly drifting, temporary formations in the sky. On a stormy day, they are dark and loud, but that is as dramatic as it gets. Conversely, Saturn's clouds have been a hexagon for as long as we've known. Each side of the hexagon is 13,800 kilometers, which is more than the diameter of Earth itself. This giant rotating hexagon resembles a hurricane with a churning storm at the center and winds ranging up to 322 kilometers per hour taming their counterparts on Earth. The largest wind system recorded on Saturn is 3540 kilometers wide, also almost double the record on Earth.
A big mystery is how the hexagon formed and what has preserved this shape over the decades. I wonder if what we already know about its size, storms, and the wind system can guide our understanding of its shape. Using this information, scientists at Oxford University tried to recapitulate the conditions on Saturn's North pole and observed what shapes can arise in the laboratory. They rotated a cylindrical tank of liquid at various speeds and noticed that this resulted in the formation of a six-sided shape. Scientists realized that the faster they spun, the less sides the polygon had, and vice versa. Although this experiment lends us insights into the mechanics of hexagon formation, many questions remain. For example, how is the hexagon maintained? Has it always been a hexagon, or did it evolve from another shape? Will it ever change shapes? Why is there no hexagon on Saturn's South pole? Do similar cloud formations exist elsewhere in the universe?
Efforts to understand Saturn's hexagon also inspire the study of hexagons much closer and more relevant to us. Hexagons are plentiful on Earth, but they exist in the microscopic realm compared to Saturn's. Viruses evolve rapidly, but continue to enclose their genomes in a hexagonal coat. Similarly, bees have evolved to build honeycombs with hexagonal cells to maximize space. Snowflakes and aromatic rings in molecules spontaneously form hexagons. This target launches us to uncover evolutionary parallels underlying diverse hexagon formations in the universe."
Seven Lakes High School
Teacher: Clark Saunders
"The strange hexagonal storm on Saturn is a turbulent place which has raised many questions since Cassini reached the planet in July of 2004. Theorized by scientists to be caused by slight perturbations in the jet stream, the storm still has many mysteries waiting to be solved. Labelled 'Target 3', I believe that researching this image and this storm will reveal the most interesting results.
The New Mexico Institute of Mining and Technology ran a computer simulation in late 2015, proposing that the hexagonal storm may be caused by slight disturbances in an eastward moving jet stream. It could also be that the atmospheric winds at higher latitudes are moving faster than the winds at lower latitudes. But still, this report provides answers to only a few questions and raises many more. One such question is how this storm has managed to stay stable. Some, like the article titled 'Dynamics of Saturn's Polar Regions' in the Journal of Geophysical Research, have hypothesised that because of its 'remarkable stability of its rotation rate through polar seasons, the storm may be caused by deeply rooted atmospheric structures', that tie the storm to the atmosphere of the planet. They also say that exploring this phenomenon could reveal the 'internal planetary rotation rate that is currently constrained by measurements of magnetic field'. We could also finally figure out the wind speed of Saturn's atmosphere, undoubtedly being a great help in future missions. Not only this, but greater knowledge of the storm could increase our understanding of turbulent flow in fluid dynamics, which will allow us to create better airplanes on earth that reduce turbulence, fly faster, and are more efficient. It could also help us predict the weather better and even assist in environmental engineering.
The biggest reason why this image stands out is because it shows a dynamic system, that yet can be measured and in which changes can be analyzed. One such change was the apparent color shift of the storm from a bluish haze to a golden brown hue, in October of last year. Scientists have theorized that this could be caused by the changing seasons of Saturn, which makes it receive more sunlight, which makes more haze particles that begin to resemble the rest of Saturn's atmosphere. This could provide a new insight into the atmospheric composition of Saturn, and help us understand how particles react with light. It also begs the questions, what if the storm didn't receive sunlight? Would it change back to its bluish color? And if it doesn't, what really causes the color shifts? An in-depth analysis would surely answer these questions, and only create more exciting discoveries for us to analyze.
Rather than Enceladus' plumes and Titan's lakes, the gargantuan storm on Saturn with a peculiar shape will definitely reveal the most interesting results. Its relative accessibility for the Cassini spacecraft, and the changing nature of the storm puts this image at the top of NASA's priority list."