Reprocessed view by Bjorn Jonsson of the Great Red Spot taken by Voyager 1 in 1979 reveals an incredible wealth of detail.
If it weren’t for the Sun, Jupiter’s Great Red Spot would be a much blander feature on the gas giant, a new study reveals. This stands apart from what most scientists think about why for why the spot looks so colorful: that there are features in the clouds that give it its distinctive shade.
The new data comes from observations with the Cassini spacecraft, combined with experiments in the lab. They conclude that the Red Spot’s immense height, combined with sunlight breaking apart the atmosphere there into certain chemicals, make the feature that red that is visible even in small telescopes.
“Our models suggest most of the Great Red Spot is actually pretty bland in color, beneath the upper cloud layer of reddish material,” said Kevin Baines, a Cassini team scientist based at NASA’s Jet Propulsion Laboratory in California, in a statement. “Under the reddish ‘sunburn’ the clouds are probably whitish or grayish.”
The lab experiments combined ammonia and acetylene gases (atmospheric components from Jupiter) with ultraviolet light (simulating what the Sun produces), which created a ruddy substance that matched observations made with the Cassini spacecraft back in 2000. They also tried breaking apart ammonium hydrosulfide, a common element in Jupiter’s high clouds, but the color produced was actually a bright green.
The Great Red Spot is a storm that has been raging on Jupiter since at least when telescopes were first used in the 1600s. Over the past few decades, its size has shrunk considerably –it’s now half of what historical measurements showed — but it is still much larger than Earth. Scientists are hoping the forthcoming Juno mission, which will arrive at Jupiter at 2016, will help learn more about what is going on.
Results were presented at the Division for Planetary Science of the American Astronomical Society’s annual meeting this week in Tucson, Arizona. A press release did not disclose publication plans or if the research is peer-reviewed.
Missing the planets this month? With Mars receding slowly to the west behind the Sun at dusk, the early evening sky is nearly devoid of planetary action in the month of November 2014. Stay up until about midnight local, however, and brilliant Jupiter can be seen rising to the east. Well placed for northern hemisphere viewers in the constellation Leo, Jupiter is about to become a common fixture in the late evening sky as it heads towards opposition next year in early February.
The line-up during the November 25th eclipse event (see chart below). Note that Jupiter’s moons are in 1-2-3-4 order! Credit: Stellarium.
An interesting phenomenon also reaches its climax, as we make the first of a series of passes through the ring plane of Jupiter’s moons this week on November 8th, 2014. This means that we’re currently in a season where Jupiter’s major moons not only pass in front of each other, but actually eclipse and occult one another on occasion as they cast their shadows out across space.
These types of events are challenging but tough to see, owing to the relatively tiny size of Jupiter’s moons. Followers of the giant planet are familiar with the ballet performed by the four large Jovian moons of Io, Europa, Ganymede, and Callisto. This was one of the first things that Galileo documented when he turned his crude telescope towards Jupiter in late 1609. The shadows the moons cast back on the Jovian cloud tops are a familiar sight, easily visible in a small telescope. Errors in the predictions for such passages provided 17th century Danish astronomer Ole Rømer with a way to measure the speed of light, and handy predictions of the phenomena for Jupiter’s moons can be found here.
A look at selected upcoming occultation events. Credit: Starry Night.Credit and copyright Christoper Go, used with permission.
Mutual occultations and eclipses of the Jovian moons are much tougher to see. The moons range in size from 3,121 km (Europa) to 5,262 km (Ganymede), which translates to 0.8”-1.7” in apparent diameter as seen from the Earth. This means that the moons only look like tiny +6th magnitude stars even at high magnification, though sophisticated webcam imagers such as Michael Phillips and Christopher Go have managed to actually capture disks and tease out detail on the tiny moons.
A double shadow transit from 2013. Photo by author.
What is most apparent during these mutual events is a slow but steady drop in combined magnitude, akin to that of an eclipsing variable star such as Algol. Running video, Australian astronomer David Herald has managed to document this drop during the 2009 season (see the video above) and produce an effective light curve using LiMovie.
Such events occur as we cross through the orbital planes of Jupiter’s moons. The paths of the moons do not stray more than one-half of a degree in inclination from Jupiter’s equatorial plane, which itself is tilted 3.1 degrees relative to the giant planet’s orbit. Finally, Jupiter’s orbit is tilted 1.3 degrees relative to the ecliptic. Plane crossings as seen from the Earth occur once every 5-6 years, with the last series transpiring in 2009, and the next set due to begin around 2020. Incidentally, the slight tilt described above also means that the outermost moon Callisto is the only moon that can ‘miss’ Jupiter’s shadow on in-between years. Callisto begins to so once again in July 2016.
Mutual events for the four Galilean moons come in six different flavors:
A look at the six types of phenomena possible with Jupiter’s four large moons. Created by the author.
This month, Jupiter reaches western quadrature on November 14th, meaning that Jupiter and its moons sit 90 degrees from the Sun and cast their shadows far off to the side as seen from the Earth. This margin slims as the world heads towards opposition on February 6th, 2015, and Jupiter once again joins the evening lineup of planets.
Early November sees Jupiter rising around 1:00 AM local, about six hours prior to sunrise. Jupiter is also currently well placed for northern hemisphere viewers crossing the constellation Leo.
The Institut de Mécanique Céleste et de Calcul des Éphémérides (IMCCEE) based in France maintains an extensive page following the science and the circumstances for the previous 2009 campaign and the ongoing 2015 season.
We also distilled down a table of key events for North America coming up through November and December:
A look at selected events through the end of 2014. 1=Io, 2=Europa, 3=Ganymede, 4=Callisto. O=Occultation, E=Eclipse. Created by the author, adapted from the IMCCEE chart for the 2014-15 season.
Fun fact: we also discovered during our research for this piece that these events can also produce a total solar eclipse very similar to the near perfect circumstances enjoyed on the Earth via our Moon:
Note that this season also produces another triple shadow transit on January 24th, 2015.
Observing and recording these fascinating events is as simple as running video at key times. If you’ve imaged Jupiter and its moons via our handy homemade webcam method, you also possess the means to capture and analyze the eclipses and occultations of Jupiter’s moons.
A view never seen from the Earth… Io (upper left) paired with a crescent Europa during New Horizons’ 2007 flyby. Credit: NASA/JPL.
Good luck, and let us know of your tales of astronomical tribulation and triumph!
Jupiter's Great Red Spot and Ganymede's Shadow. Image Credit: NASA/ESA/A. Simon (Goddard Space Flight Center)
Halloween is just around the corner. And in what appears to be an act of cosmic convergence, Hubble captured a spooky image of Jupiter staring back at us with a cyclops eye!
While this is merely a convenient illusion caused by the passage of Ganymede in front of Jupiter – something it does on a regular basis – the timing and appearance are perfect.
A view of Mimas from the Cassini spacecraft. Credit: NASA/JPL/Space Science Institute
Could there be an ocean hidden somewhere in that Death Star-like picture? This is an image of Mimas, a moon of Saturn, and just yesterday (Oct. 15) newly released data from the Cassini spacecraft suggests there are big liquid reservoirs underneath its surface.
“The amount of the to-and-fro motion indicates that Mimas’ interior is not uniform. These wobbles can be produced if the moon contains a weirdly shaped, rocky core or if a sub-surface ocean exists beneath its icy shell,” said Cornell University in a press release. More flybys with the Cassini spacecraft will be required to learn more about what lies beneath.
You can read more about the study (led by Cornell astronomy research associate Radwan Tajeddine) in Science, where it was published. Below, learn more about other worlds in the Solar System that could host oceans under their surface.
Enceladus
Cassini images of Saturn’s moon Enceladus backlit by the sun show the fountain-like sources of the fine spray of material that towers over the south polar region. This image was taken looking more or less broadside at the “tiger stripe” fractures observed in earlier Enceladus images. It shows discrete plumes of a variety of apparent sizes above the limb (edge) of the moon. This image was acquired on Nov. 27, 2005. Image Credit: NASA/JPL/Space Science Institute
After nearly a decade of speculation, this year the Cassini spacecraft returned gravity data suggesting Enceladus (another moon of Saturn) does have a large subsurface ocean near its south pole, if not a global ocean. If confirmed, that could help explain why scientists see water gushing out of fractures in that area. As this recent paper by Cassini scientists shows, Enceladus is a promising location for habitability.
Titan
A halo of light surrounds Saturn’s moon Titan in this backlit picture, showing its atmosphere. Credit: NASA/JPL/Space Science Institute
By the way, anyone noticed that we still haven’t even left Saturn’s system? Titan is usually high on astrobiology wish lists for researchers because its hydrocarbon chemistry could be precursors to how life evolved. What’s not talked about as much, though, is at least two research findings pointing to evidence of a hidden ocean. Evidence comes from Titan’s tidal flexing from interacting with Saturn — which is 10 times more than what would be expected with a solid core — and the way that it moves on its own axis as well as around Saturn.
Europa
Rendering showing the location and size of water vapor plumes coming from Europa’s south pole. Credit: NASA/ESA/L. Roth/SWRI/University of Cologne
That Minecraft-looking object floating beside Europa there is a rendering showing where water vapor erupted from the Jovian moon, spotted by the Hubble Space Telescope in 2013. We were lucky enough to have a close-up view of Europa in the 1990s and early 2000s courtesy of NASA’s Galileo spacecraft. What we know for sure is there’s thick ice on Europa. What’s underneath is not known, but there’s long been speculation that it could be a subsurface ocean that may have more water than our own planet.
Io
Jupiter’s volcanic moon Io , imaged by the Galileo spacecraft in 1997. Credit: NASA/JPL/University of Arizona
Still flying around Jupiter here, we now turn our attention to Io — a place that is often remarked upon because of its blotchy appearance as well as all of the volcanoes on its surface. A newer analysis of Galileo data in 2011 — looking at some of the lesser-understood magnetic field data signatures — led one research team to conclude there could be a magma ocean lurking underneath that violence.
Triton
A glimpse of Triton from the Voyager 2 spacecraft, which flew by the Neptunian moon in August 1989. Credit: NASA/JPL
Little is known about Triton because only one spacecraft whizzed by it — Voyager 2, which took a running pass through the Neptune system in August 1989. An Icarus paper two years ago speculated that the world could host a subsurface ocean, but more data is needed. The energy of Neptune (which captured Triton long ago) could have melted its interior through tidal heating, possibly creating water from the ice in its crust.
Charon
Hubble image of Pluto and some of its moons, Charon, Nix and Hydra. Image Credit: NASA, ESA, H. Weaver (JHU/APL), A. Stern (SwRI), and the HST Pluto Companion Search Team
We don’t have any close-up pictures of this moon of Pluto yet, but just wait a year. The New Horizons spacecraft will zoom past Charon and the rest of the system in July 2015. In the meantime, however, findings based on a model came out this summer in Icarus suggesting Charon — despite being so far from the Sun — might have had a subsurface ocean in the past. Or even now. The key is its once eccentric orbit, which would have produced tidal heating while interacting with Pluto. The science team plans to look for cracks that could be indicative of “the structure of the moon’s interior and how easily it deforms, and how its orbit evolved,” stated Alyssa Rhoden of NASA’s Goddard Space Flight Center in Maryland, who led the research.
Artist's conception of CubeSats near Europa (left) and Jupiter. Credit: NASA/JPL
When you’ve got a $2 billion mission concept to head to Europa, it’s likely a good idea to pack as much science on this mission as possible. That’s the thinking that NASA had as it invited 10 universities to send their ideas for CubeSats — tiny satellites — that would accompany the Europa Clipper mission to the Jupiter system.
Europa Clipper is only on the drawing board right now and not fully funded, and should not be confused with the lower-cost $1 billion Europa mission that NASA proposed earlier this year (also not fully funded). But however NASA gets there, the agency is hoping to learn if the moon could be a good spot for life.
Each university is being awarded up to $25,000 to develop their ideas further, and they will have until next summer to work on them. Investigations include searching the surface for future landing sites, or examining Europan properties such as gravity, its atmosphere, magnetic fields or radiation.
Two reddish spots (Thera and Thrace) stick out on this image of Europa taken by the Galileo orbit in the 1990s. NASA says they display “enigmatic terrain.” Credit: NASA/JPL/University of Arizona
“Using CubeSats for planetary exploration is just now becoming possible, so we want to explore how a future mission to Europa might take advantage of them,” said Barry Goldstein, pre-project manager for the Europa Clipper mission concept, in a press release.
If Europa Clipper flies, it would do at least 45 flybys at altitudes between 16 miles and 1,700 miles (25 kilometers and 2,700 kilometers.) Part of its expense comes from the long distance, and also from all the radiation shielding the spacecraft would need as it orbits immense Jupiter.
Science instruments are still being figured out, but some ideas include radar (to look under Europa’s crust), an infrared spectrometer (to see what is on the ice), a camera to image the surface and a spectrometer to look at the moon’s thin atmosphere.
While there are no Europa missions officially booked now, NASA does have an active spacecraft called Juno that will arrive at Jupiter in July 2016.
Looking to the future of space exploration, NASA and TopCoder have launched the "High Performance Fast Computing Challenge" to improve the performance of their Pleiades supercomputer. Credit: NASA/MSFC
TORONTO, CANADA – Could NASA’s new rocket bring a probe to sample the geysers of Saturn’s moon Enceladus, or ferry human explorers to the surface of Mars? Representatives of contractor Boeing think so.
They’ve put together some ideas for sending their Space Launch System to these far-flung destinations, which they presented at the International Astronautical Congress today (Oct. 1).
Bear in mind that the SLS hasn’t yet flown — it’s slated for 2018 if funding lasts and the schedule holds — and the destinations below are just in the conceptual stage. The gallery below summarizes some of the destinations SLS could visit. For more information, check out this brochure by Boeing.
Enceladus
Artist’s conception of the Cassini spacecraft flying amid geysers on Enceladus, a moon of Saturn. Credit: Karl Kofoed / NASA
The icy moon of Saturn is known as a hotspot for geysers; earlier this year, scientists found 101 gushers using data from the prolific Cassini probe. Using the SLS could bring a satellite there in four years, as opposed to about seven with rockets on the market today, according to Boeing. It also could carry a heavier spacecraft.
Europa
Artist’s conception of Europa’s surface, backdropped by planet Jupiter. Credit: NASA/JPL-Caltech
Europa is known to have a subterranean ocean, and it also is capable of spewing water plumes — as researchers using the Hubble Space Telescope discovered earlier this year. The SLS could get to Europa a lot faster than a launch with an Atlas, according to Boeing — it would only take two years to fly there directly as opposed to more than six years with the Atlas, which would need to fly by Venus first to pick up some speed.
Trojan asteroids
Artist’s diagram of Jupiter and some Trojan asteroids nearby the gas giant. Credit: NASA/JPL-Caltech
Trailing before and after Jupiter are more than a million asteroids that are called Trojans. This means any probe in the area would have no lack of targets to study, providing it had enough fuel on board. A mission profile from Boeing suggests the SLS could bring a spacecraft out there that could swing by a target at least half a dozen times.
Mars
Artist’s impression of astronauts exploring Mars. Credit: NASA/Pat Rawlings, SAIC
One of the largest challenges of getting to Mars is figuring out how to send all the life-support equipment and food that humans require — on top of the humans themselves! Since SLS is a heavy-lift rocket, Boeing is trying to position its rocket as the ideal one to get humans to Mars. But it remains to be seen what concept works best to get people out there.
The Moon
Artist’s impression of astronauts on the moon. This image was used to illustrate a landing concept of NASA’s now defunct Constellation program. Credit: John Frassanito and Associates / NASA
Boeing has an idea to bring a lander down to the Moon that could then lift off multiple times in search of other destinations. Such a concept would require a hefty amount of fuel and equipment. If it works, Boeing says the SLS could assist with plans for lunar mining and other exploration ideas.
Jupiter at Dawn from Savannah Skies Observatory - Sept 20, 2014. Credit and copyright: Joseph Brimacombe.
Prolific astrophotographer Joseph Brimacombe from Australia shot this beauty from his Savannah Skies Observatory near Cairns. He notes on Flickr that “Jupiter has been enhanced for effect,” but what a lovely effect! Plus what a great view of the landscape in Queensland.
Taken with a Canon 5D Mk II and 28-300 mm lens, six frames; three exposures each.
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Reprocessed Galileo image of Europa's frozen surface by Ted Stryk (NASA/JPL/Ted Stryk)
Mysteries abound on icy Europa, that cold moon of Jupiter. Even years after the Galileo spacecraft finished its mission in the Jovian system, scientists are still trying to figure out the nature of the cracks on Europa’s surface. In an exciting find, one new paper suggests that at least part of the terrain could be due to plate tectonics.
If proven, this would be the first time that plate tectonics have been strongly suggested as a process working beyond Earth. On our home planet, scientists believe that this process, which happens as plates of Earth’s crust move, is responsible for creating mountains and volcanoes and earthquakes.
So why do they think this process is happening on Europa? The short answer is, weird terrain. For example, Scientists have seen evidence of what is called extension, which happens when the surface expands and then stuff from the layers below fills in the gap. But there were pieces of that understanding missing until now, the team says.
“We have been puzzled for years as to how all this new terrain could be formed, but we couldn’t figure out how it was accommodated,” stated Louise Prockter, a planetary scientist at Johns Hopkins University Applied Physics Laboratory who co-authored the study. “We finally think we’ve found the answer.”
An illustration of how subducting tectonic plates might work on Jupiter’s moon, Europa. This would bring the moon’s estimated 10-20 mile (20-30 kilometer) ice shell into the warmer insides of the moon. Credit: Noah Kroese, I.NK
Despite being pretty confident about the extension, scientists were unable to account for how all the new material arrived.
What the team did was try to model how Europa’s surface looked before how all the cracks appeared, and discovered that 7,700 square miles (20,000 square kilometers) couldn’t be accounted for in the high northern latitudes.
Looking more closely, they found ice volcanoes that they believe was on a surface plate, and missing mountains in what is thought to be a subduction zone. This suggests that stuff from the surface gets pushed underneath — not crushed into each other.
Rendering showing the location and size of water vapor plumes coming from Europa’s south pole. Credit: NASA/ESA/L. Roth/SWRI/University of Cologne
“Europa may be more Earth-like than we imagined, if it has a global plate tectonic system,” stated Simon Kattenhorn of the University of Idaho, Moscow, who led the study.
“Not only does this discovery make it one of the most geologically interesting bodies in the solar system, it also implies two-way communication between the exterior and interior — a way to move material from the surface into the ocean — a process which has significant implications for Europa’s potential as a habitable world.”
A panoramic view of the Venus Jupiter Conjunction on August 17, 2014, taken from the Cairns Esplanade in Queensland Australia. Credit and copyright: Joseph Brimacombe.
The closest planetary conjunction of the year graced the skies this morning, and astrophotographers were out in force to marvel at the beauty. The duo were just 11.9’ apart, less than half the diameter of a Full Moon. Also joining the view was M44, the Beehive Cluster. We start with this gorgeous shot from Queensland, Australia by one of our longtime favorite astrophotographers, Joseph Brimacombe.
But wait… there’s more! Much more! See below:
The Jupiter and Venus conjunction on August 18, 2014 along with the Beehive Cluster. Credit and copyright: Tom Wildoner.Telescopic view of Venus and Jupiter in the morning sky over Lahore, Pakistan. Shot with a Nikon D5100. Credit and copyright: Roshaan Bukhari.Beautiful conjunction of Jupiter and Venus over the Appennines on August 18, 2014. The foreground in the image shows the Peligna Valley in central Italy and the city of Sulmona. Credit and copyright: Giuseppe PetriccaJupiter-Venus-M44 conjunction on August 18, 2014. Image taken with Canon EOS 50D, through Skywatcher ED80. Credit and copyright: Zoran Novak.Close approach of Venus and Jupiter with M44 in the same field on August 18, 2014 over Payson, Arizona. Shot with a Canon XTi DSLR, 5 seconds exposure, ISO 400, 4″ f/4.5 Newtonian. Credit and copyright: Chris Schur.Conjunction between the planets Venus(top) and Jupiter (bottom) as seen from London just before dawn on 18th August 2014. Credit and copyright: Roger Hutchinson.Tight grouping of Venus and Jupiter, captured at twilight on an 18 day old moon, one can see the two planets less than 1 degree apart in the sky. This image was captured at Damdama Lake, Haryana, India. Credit and copyright: Rishabh Jain. When Venus and Jupiter were almost touching in the sky! August 18, 2014 over Königswinter-Heisterbacherrott in Germany. Credit and copyright: Daniel Fischer.Venus and Jupiter 1/2 degree apart low in the pink twilight at lower left, with the waning crescent Moon near Aldebaran at upper right, taken from Alberta Canada on August 18, 2014 at dawn, looking due east. This is a single 1 second exposure at f/4 with the 16-35mm lens and Canon 6D at ISO 800. Credit and copyright: Alan Dyer/Amazing Sky Photography.Venus-Saturn conjunction on August 18, 2014, as see from Topaz Lake on the California – Nevada border. Credit and copyright: Jeff Sullivan/Jeff Sullivan Photography.A sample of four images in various locations/moments at Pescara, Italy. Credit and copyright: Marco Di Lorenzo.
Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.
This animated gif shows Voyager 1's approach to Jupiter during a period of over 60 Jupiter days in 1979. Credit: NASA.
Back in the 1970’s when NASA launched the two Voyager spacecraft to Jupiter, Saturn, Uranus, and Neptune, I remember being mesmerized by a movie created from Voyager 1 images of the movement of the clouds in Jupiter’s atmosphere. Voyager 1 began taking pictures of Jupiter as it approached the planet in January 1979 and completed its Jupiter encounter in early April. During that time it took almost 19,000 pictures and many other scientific measurements to create the short movie, which you can see below, showing the intricate movement of the bright band of clouds for the first time.
Now, 35 years later a group of seven Swedish amateur astronomers achieved their goal of replicating the Voyager 1 footage, not with another flyby but with images taken with their own ground-based telescopes.
“We started this joint project back in December of 2013 to redo the NASA Voyager 1 flyby of Jupiter,” amatuer astronomer Göran Strand told Universe Today. “During 90 days we captured 560 still images of Jupiter and turned them into 90 complete maps that covered the whole of Jupiter’s surface.”
Their newly released film, above details the work they did and the hurdles they overcame (including incredibly bad weather in Sweden this winter) to make their dream a reality. They called their project “Voyager 3.”
Animated gif of the ‘Voyager 3’ team re-enactment of the Voyager 1 flyby. Credit: Voyager 3 team, via Kristoffer Åberg.It is really an astonishing project and those of you who do image processing will appreciate the info in the video about the tools they used and how they did their processing to create this video.
The seven Swedish astronomers who participated in the Voyager 3 project are (from left to right in the photo below) Daniel Sundström, Torbjörn Holmqvist, Peter Rosén (the project initiator), Göran Strand, Johan Warell and his daughter Noomi, Martin Högberg and Roger Utas.
The Swedish team of amateur astronomers who compiled the ‘Voyager 3’ project. Image courtesy Peter Rosén.
