What Humanity Can Gain From Other Moons | Cosmic Vistas | Spark

for generations our world has challenged explorers to seek what lies beyond the horizon now the invention of space flight is leading us outward to explore a host of alien worlds with vast new territories today we see the sun moon and planets with penetrating clarity through the eyes of the intrepid machines blazing a trail for us across the solar system their cameras have become our windows onto a bold new adventure their discoveries have become our cosmic [Music] vistas [Music] [Music] there are more than 100 moons in our solar system the vast majority of them orbit the two largest planets jupiter and saturn collectively they run the gamut from small to large cold too hot and quiet too active could it be that somewhere in that range of possibilities we will find a hidden haven for alien life [Music] most of the moons that orbit jupiter and saturn are quite small but a few are so large and complex they could easily be considered planets for more than 300 years there was almost nothing astronomers could say about these intriguing places thanks to space flight that's no longer the case in 1979 voyager 1 and voyager 2 sailed past jupiter's four largest moons with their cameras rolling the pictures they radioed back reveal that each moon has its own distinct character and a range of features unlike anything seen before the biggest surprise of all was io the innermost of the four moons its rocky surface is a mottled and sulfurous mess unlike our moon there are no craters on io it's as though they are being erased by some mysterious agent the explanation came when voyager 1 spied something unusual protruding 300 kilometers from one side of io it was a fountain of ash spewing from a large volcano since that discovery it's now become clear io is the most geologically active world in the solar system io's surface is one vast lava flow with more than a dozen active volcanoes towering over the sulfur-rich landscape the gravitational pull of jupiter and some of its other large moons creates a tug of war inside io which generates vast amounts of heat [Music] while this makes for a dynamic surface it is not particularly hospitable to life jupiter's outermost large moon callisto couldn't be more different callisto's battered face is saturated with ancient impact craters suggesting not much has happened here since callisto formed but looks can be deceiving the most recent data suggest there could be a zone of salty water somewhere deep below callisto's surface of ice and rock whether life could survive in such a hidden environment remains an open question meanwhile on ganymede we find more obvious signs of a geologically active past ganymede is the largest moon in our solar system and one of the strangest looking part of its surface is as old as callisto's dark and heavily cratered but the dark areas are fractured by a more recent terrain made up of parallel grooves and ridges exactly how these grooves and ridges formed is still a big mystery it is clear ganymede has a warmer interior than callisto in the past that warmth may have risen up through ganymede's interior and forced sections of its surface to drift apart just like the continents on earth because of its heat ganymede's interior has likely separated into layers starting with an iron-rich core at the center a surrounding mantle of rock and a thick layer of ice on top of that as with callisto there is evidence on ganymede for an ocean of salt water somewhere below the surface this is exciting news because the right combination of heat and water may provide the conditions necessary for life on ganymede such life forms would be cut off from the sun and the surface environment but like the creatures that live around deep sea vents in earth's oceans it might survive on chemical energy this tantalizing possibility won't be tested anytime soon if ganymede has an ocean it's at least 200 kilometers below its frozen surface a better opportunity for exploring the ocean of another world may exist on europa at first glance europa seems like the least interesting of jupiter's moons because its surface is so flat and smooth its lack of dramatic relief like mountains or large craters might be an indication that water isn't far below europa is crisscrossed with a network of cracks that suggest its icy crust has opened up from time to time letting a watery slush spill out onto the surface [Music] in one area scientists have found what appear to be icebergs that cracked and floated apart like rafts before the surface re-froze some of the cracks on europa have a darker and more reddish hue than the rest of the surface ice this could mean that the underlying ocean is rich in sulfur compounds and perhaps organic molecules indications are that in some places this ocean may be less than 10 kilometers from the surface possibly within reach of a future attempt to drill down and explore the marine environment of another world today europa's ocean is high on the list of locations where scientists are eager to search for alien life the surfaces of jupiter's moons may conceal many mysteries but on saturn's giant moon titan even the surface is hidden from view titan is the only moon in our solar system with a substantial atmosphere and it shows when voyager 1 arrived at saturn in 1980 it found titan shrouded by a thick orange haze this haze is like a photochemical smog produced when sunlight reacts with methane in titan's atmosphere it would be a full generation before scientists had their next chance at titan when the cassini mission arrived at saturn in 2004 it used a high-powered camera equipped with an infrared filter to penetrate the veil of titan's thick haze what cassini found was even stranger than expected a surface divided into mysterious light and dark regions resembling ancient coastlines cassini also bounced radar signals off of titan confirming that the moon's surface is solid with unusual landforms like ice volcanoes and wind-blown dunes after several more passes of titan cassini's radar made an even more exciting discovery a series of dark patches that were perfectly flat resembling the surfaces of small lakes scientists were eager for more direct evidence of potential fluid flow on titan they found it in dramatic fashion when cassini dropped a probe into titan's cloudy atmosphere after the probe deployed its parachute and slowly descended it radioed pictures back to cassini [Music] as soon as the probe emerged from the clouds it began to see exciting details that looked suspiciously like they had been carved by a flowing liquid then to everyone's surprise the probe survived its impact and sent back one final spectacular image [Music] it showed chunks of ice clearly rounded by fluid flow like rocks in a stream bed on earth on titan it's so cold that water is like rock but methane which is a gas here on earth can rain down from titan's atmosphere and flow as a liquid over the surface methane is a building block for the kinds of complex molecules that led to the emergence of life on earth and that means if titan has an internal heat source like some of jupiter's moons it could also be harboring its own ecosystem deep below the surface one thing is clear titan and jupiter's moons are no longer sideshows to the planets they orbit together they have become the main motivators in our exploration of the outer solar system [Music] [Applause] [Music] [Music] here on planet earth it's easy to take water for granted water covers 70 of earth's surface and its presence is essential for life as we know it [Music] farther away in the dim reaches of the outer solar system water plays a different role around saturn water is everywhere with temperatures near minus 180 degrees celsius it's far too cold for water to exist in a liquid state here water remains frozen solid so solid that it doesn't just cover worlds it makes worlds when we get to saturn we discover ice is the main ingredient in building moons in fact saturn is surrounded by an entire family of icy moons that the cassini mission has now revealed in spectacular detail by exploring these frozen worlds scientists hope to reveal an ancient story not just about saturn but about the entire outer solar system this is certainly the case with phoebe the first of saturn's moons that cassini encountered up close just 200 kilometers across phoebe is too small and it's gravity too weak to pull itself into a sphere when cassini sailed past phoebe it found a surface rich in carbon with deep craters exposing layers of bright white ice lying just below overall phoebe is darker and contains more rock than saturn's other icy moons this suggests it did not form near saturn but in the kuiper belt beyond neptune the objects inhabiting this zone are ancient the original building blocks of the outer solar system it now appears phoebe is an escapee from that region and only later captured by saturn and turned into a moon this moon is giving us a sneak preview of what we'll find at much further distances from the sun four times closer to saturn and four times larger than phoebe e apetus is a very different kind of moon it is 80 percent ice but its most distinctive feature is its strange two-tone shading while one side of the yapidos is extremely dark the other is whitish gray this color difference also corresponds to a significant temperature difference on average the dark side is 15 degrees warmer than the light side [Music] scientists now suspect that dark material possibly blasted from the surface of phoebe may have fallen down onto iapetus long ago the side that received the dust absorbed more of the sun's energy and the ice there began to sublimate leaving behind grains of dust and rock that would darken the surface even further meanwhile the vaporized ice resettled onto the other side of the apetus and around its poles creating the look it has today even stranger is a long ridge cassini discovered running along the equator of iapetus giving it the appearance of a walnut in places the ridge is 13 kilometers high the forces that created this bizarre feature are not well understood but it likely happened when eapidis was spinning more rapidly than it is now and had more internal heat shaping its surface moving even closer towards saturn we find hyperion i misshapen object with a strange honeycombed surface hyperion is so irregular in shape and appearance it is probably just a fragment from a larger moon that was destroyed in a collision it may not even be solid but a loosely packed pile of rubble measurements by cassini reveal hyperion is more than forty percent empty space signs of ancient collisions are visible everywhere on saturn's moons including ria diony and tethys at first glance this trio of round moons could be mistaken for identical triplets each one is more than one thousand kilometers across and carpeted with impact craters from billions of years ago [Music] but they are also variations on a theme each of the three has its own distinct features suggesting a more complex and diverse history for example this giant canyon called ithaca chasma wraps around tethys like a waistband it may have formed long ago when the icy interior of tethys froze and expanded forcing its crust to stretch apart at the seams looking at diony from afar scientists long wondered about a series of wispy white lines running across its surface [Applause] now cassini has revealed the lines are the bright faces of steep cliffs formed when diony was repeatedly fractured by internal forces [Music] but the biggest surprise came from ria cassini found indirect evidence this moon is surrounded by a dark dusty ring making rhea the only moon anywhere in the solar system with a ring of its own while most of saturn's icy moons were likely once geologically active worlds which later cooled and grew dormant at least one seems to have forgotten to fall asleep and the implications are enormous enceladus is only 500 kilometers across under ordinary circumstances an object of this size should be too small to retain heat for billions of years but enceladus is nowhere near ordinary here cassini spotted vast geysers of water vapor shooting outward from a region near its south pole the vapor carries fine grains of dust which escape into space and form a diffuse ring along enceladus orbital path around saturn looking down at the surface for clues cassini has revealed a strange and puzzling sight enceladus is scored with long deep gouges nicknamed tiger stripes from which the geysers are thought to emanate the stripes are surrounded by fresh eyes which suggests that somewhere below the surface temperatures are high enough to melt ice and hold liquid water under pressure before venting it into space like a tea kettle no one yet knows exactly how enceladus does this one important clue from cassini is that enceladus has more rock and metal than many other of saturn's moons and so perhaps it is being warmed by a combination of radioactive heating from within and strong tides produced by saturn and its other moons even more exciting is the presence of organic molecules near the tiger stripes when this is combined with the likelihood of liquid water it appears enceladus may have all the ingredients necessary for life for a tiny moon at the leading edge of the icy solar system this is an astonishing revelation to call the icy moons of saturn strange is an understatement these odd little worlds are utterly unlike earth but understanding how they formed and evolved is an important goal for scientists why because if there are so many icy moons in our solar system there must be countless others out there among the stars [Music] whenever one of those moons is warmed up enough to melt the ice into water there exists at least the potential for life and perhaps our best chance to answer the age-old question are we alone [Music] um

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Keywords: Astrobiology, Astronomical Discoveries, Astronomical Events, Blue Ant International, Cosmic Discoveries, Exploration, Extraterrestrial Life, Galaxies, Hidden Haven, Immersive Experience, Lunar Science, Nature, Space Investigations, Space Projections, Spaceflight, Spark, Stargazing, Stellar, Tech Videos, Telescope, Terrain

Id: pJNNzamNN8c

Length: 25min 27sec (1527 seconds)

Published: Fri Feb 12 2021