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.
PHA asteroid 2014 KM4 on approach to Jupiter in late 2021. Credit: the Solar System Dynamics JPL Small-Body Database Browser.
A recent space rock discovery has sent a minor buzz through the community that tracks such objects. And as usual, it has also begun to attract the dubious attention of those less than honorable sites — we won’t dignify them with links — that like to trumpet gloom and doom, and we thought we’d set the record straight, or at very least, head the Woo off at the pass as quickly as possible.
The asteroid in question is 2014 KM4. Discovered earlier this month, this 192 metre space rock safely passed by the Earth-Moon system at 0.17 A.U.s distant on April 21st. No real biggie, as asteroids pass lots closer all the time. For example, we just had a 6-metre asteroid named 2014 KC45 pass about 48,000 miles (about 80,000 kilometres) from the Earth yesterday morning. That’s about twice the distance of the orbit of geosynchronous satellites and 20% the distance to the Moon.
Sure, it’s a dangerous universe out there… you only have to stand in the Barringer Meteor Crater in Arizona outside of Flagstaff or watch the videos of a meteor exploding over Chelyabinsk last year the day after Valentine’s Day to know that. But what makes 2014 KM4 interesting is its orbit and its potential to approach Jupiter in about seven years.
Or not. One dilemma with orbital mechanics is that the precision of a known orbital path relies on the number of observations made and that position gets more and more uncertain as we project an object’s position ahead in space and time. 2014 KM4 is on a 5.08 year orbit inclined 5.2 degrees to the ecliptic plane that brings it juuusst inside the Earth’s orbit — hence the Apollo designation — and out to an aphelion point very near Jupiter at 5.2 A.U.s from the Sun. But that’s only based on 14 observations made over a span of 5 days. The current nominal trajectory sees 2014 KM4 pass about 0.1 A.U. or 15.5 million kilometres from Jupiter on January 16th 2022. That’s inside the orbit of Jupiter’s outermost moons, but comfortably outside of the orbit of the Galilean moons. The current chance of 2014 KM4 actually impacting Jupiter sits at around 1% and the general trend for these kinds of measurements is for the probability to go down as better observations are made. This is just what happened last year when comet 2013 A1 Siding Spring was discovered to pass very close to Mars later this year on October 19th.
We caught up with JPL astronomer Amy Mainzer, Principal Investigator on the NEOWISE project currently hunting for Near Earth Asteroids for her thoughts on the subject.
“The uncertainty in this object’s orbit is huge since it only has a 5 day observational arc,” Mainzer told Universe Today. “A quick check of the JPL NEO orbit page shows that the uncertainty in its semi-major axis is a whopping 0.47 astronomical units! That’s a huge uncertainty.”
“At this point, any possibility of impact with Jupiter is highly uncertain and probably not likely to happen. But it does point out why it’s so important to extend observational arcs out so that we can extend the arc far enough out so that future observers can nab an object when it makes its next appearance.”
Jupiter takes a beating from Comet Shoemaker-Levy 9. Credit: NASA/Hubble Space Telescope team.
IF (that less than 1% “IF”) 2014 KM4 were to hit Jupiter, it would represent the most distant projection ahead in time of such an event. About two decades ago, humanity had a front row seat to the impact of comet Shoemaker-Levy 9 into Jupiter in July 1994. At an estimated 192 metres in size, 2014 KM4 is about the size of the “D” fragment that hit Jupiter on July 17th 1994. 2014 KM4 has an absolute magnitude (for asteroids, this is how bright they’d appear at 1 A.U. distant) of +21.3 and is currently well placed for follow up observations in the constellation Virgo.
And astronomer Nick Howes mentioned to Universe Today that the Faulkes Telescope North may soon be used to make further observations of 2014 KM4. In the meantime, you can enjoy the animation of their observations of another Near-Earth Asteroid, 2014 KP4.
An animation of the motion of PHA asteroid 2014 KP4. Credit: Remanzacco Observatory.
And yes, the 2022 pass of 2014 KM4 near Jupiter will modify the orbit of the asteroid… but not in our direction. Jupiter is a great “goal tender” in this regard, protecting the inner solar system from incoming hazards.
2014 KM4 is well worth keeping an eye on, but will most likely vanish from interest until it returns to our neck of the solar system in 2065. And no, a killer asteroid won’t hit the Earth in 2045, as a CNN iReport (since removed) stated earlier this week… on “March 35th” no less. Pro-tip for all you conspiracy types out there that think “Big NASA” is secretly hiding the next “big one” from the public: when concocting the apocalypse, please refer to a calendar for a fictional date that at least actually exists!
Hubble nabs a triple shadow transit in this false color image taken in 2004. Credit: NASA/HST.
The planet Jupiter is always fascinating to watch. Not only do surface features pop in and out of existence on its swirling cloud tops, but its super fast rotation — once every 9.9 hours — assures its face changes rapidly. And the motion of its four large Galilean moons is captivating to observe as well. Next week offers a special treat for well-placed observers: a triple shadow transit of the moons Callisto, Europa and Ganymede on the evening of June 3rd.
The view at 19:00 UT/3:00 PM EDT on June 3rd. Credit: Starry Night Education Software.
Now for the bad news: only a small slice of the planet will witness this rare treat in dusk skies. This is because Jupiter starts the month of June 40 degrees east of the Sun and currently sets around 11 PM local, just 3 hours after local sunset. Never fear, though, it may just be possible to spy a portion of this triple transit from North American longitudes with a little careful planning.
The action begins on June 3rd at 15:20 Universal Time as Callisto’s shadow slides on to the disk of Jupiter, to be followed by Europa and Ganymede’s shadow in quick succession hours later. All three shadows are cast back onto the disk of Jupiter from 18:05 to 19:53 UT, favoring European and African longitudes at sunset. The final shadow, that of Ganymede, moves off the disk of Jupiter at 21:31 UT.
The hemisphere of the Earth facing towards Jupiter from the beginning of the triple shadow transit to the end. the red line marks the day/night terminator. Credit: Stellarium.
The following video simulation begins at around 15:00 UT just prior to the ingress of Callisto’s shadow and runs through 22:00 UT:
Triple shadow transits of Jupiter’s moons are fairly rare: the last such event occurred last year on October 12th, 2013 favoring North America and the next won’t occur until January 24th, 2015. Jean Meeus calculated that only 31 such events involving 3 different Jovian moons either transiting Jupiter and/or casting shadows onto its disk occur as seen from Earth between 1981 and 2040. The June 3rd event is also the longest in the same 60 year period studied.
The 1:2:4 orbital resonance of the Jovian moons Io, Europa and Ganymede. Credit: Wikimedia Commons.
Can four shadow transits occur at once? Unfortunately, the answer is no. The inner three moons are in a 1:2:4 resonance, meaning that one will always be left out of the picture when two are in front. This also means that Callisto must be included for any triple shadow transit to occur. Next week’s event sees Callisto, Europa and Ganymede crossing in front of Jupiter and casting shadows onto its disk while Io is hidden behind Jupiter in its enormous shadow. Callisto is also the only one of the four large Jovian moons that can “miss” the disk of Jupiter on certain years, owing to the slight inclination of its orbit to the ecliptic. Callisto thus doesn’t always cast a shadow onto the disk of Jupiter, and we’re currently in the middle of a cycle of Callisto shadow transits that started in July of 2013 and runs through July 2016. These “Callisto transit seasons” occur twice during Jupiter’s 11.8 year orbit, and triple shadow transits must also occur within these periods.
So, what’s a North American observer to do? Well, it is possible to spot and track Jupiter with a telescope in the broad daylight. Jupiter rises at around 9:20 AM local in early June, and the waxing crescent Moon passes 5.4 degrees south of it on June 1st. The Moon stands 30 degrees from the planet on June 3rd, and it may be juuusst possible to use it as a guide to the daytime event. A “GoTo” telescope with precise pointing will make this task even easier, allowing you to track Jupiter and the triple shadow transit across the daytime sky from North American longitudes. But be sure to physically block the blazing June Sun behind a building or structure to avoid accidentally catching its blinding glare in the eyepiece!
The orientation of Jupiter, the Moon and the Sun at 4PM EDT on June 3rd. Credit: Stellarium.
Do the shadows of the moons look slightly different to you? A triple shadow transit is a great time to compare them to one another, from the inky hard black dot of the inner moons Europa and Io, to the diffuse large shadow of Callisto. With practice, you can actually identify which moon is casting a shadow during any transit just by its size and appearance!
A study of three multi-shadow transits: last year’s (upper left) a double shadow transit from early 2014 (upper right) and 2004 (bottom). Photos by author.
Shadow transits of Jupiter’s moons also played an interesting role in the history of astronomy as well. Danish astronomer Ole Rømer noted that shadow transits were being observed at slightly different times than predicted depending on the distance of Jupiter and the Earth, and made the first rough calculation of the speed of light in 1676 based on this remarkable insight. Celestial navigators were also intrigued for centuries with the idea of using the phenomena of Jupiter’s moons as a natural clock to gauge longitude. It’s a sound idea in theory, though in practice, it proved tough to make accurate observations from the pitching deck of a ship at sea.
Jupiter captured near the daytime Moon. Photo by author.
Miss the June 3rd event? There’s still two fine opportunities to see Jupiter do its impression of the Earth-Moon system and appear to have only one satellite – Callisto – on the evenings of May 30th and June 7th.
From there, Jupiter slides lower into the dusk as June progresses and heads towards solar conjunction on July 24th.
Let us know if you manage to catch sight of this rare event!
-Send those shadow transit pics in to Universe Today at our Flickr forum.
This artist's concept of Jupiter's moon Ganymede, the largest moon in the solar system, illustrates the club sandwich model of its interior oceans. Credit: NASA/JPL
Moons with subsurface oceans are all the rage these days. There’s Europa, Titan, and just recently Enceladus joined the short list of moons that likely harbor large amounts of subsurface water.
Jupiter’s moon Ganymede – the largest moon in the solar system — has long been a member of this club. The idea of this moon having water deep within its surface first “surfaced” back in 1970, and in 2000 after the Galileo mission flew by Ganymede, data confirmed the moon’s ocean, and showing it extends to depths of hundreds of miles, with additional evidence of salty seas.
Now, a new study says that the configuration of this moon’s interior might be more like a club sandwich, according to Steve Vance of NASA’s Jet Propulsion Laboratory, who led the research.
“Ganymede’s ocean might be organized like a Dagwood sandwich,” Vance said in a NASA press release, with ice and oceans stacked up in several layers, as in the graphic above.
The results also support the idea that primitive life may have possibly arisen on this icy moon.
Ganymede is about to hide behind Jupiter. Credit: NASA, ESA, and E. Karkoschka (University of Arizona)
This layered look was actually proposed last year by Vance and his team, and this latest research is based on theoretical computer modeling, where areas previously thought to be layers and lumps of just rocks and ice in Ganymede’s interior are actually layers of ice, water and rock.
Usually, places where water and rock interact are ripe for the development of life, scientists say. For example, its possible life began on Earth in bubbling vents on our sea floor.
The model computed by Vance and his team gets complicated when the different forms of ice are taken into account, which can cause varying amounts of pressure. This can change the whole dynamics of the moon’s interior.
If the lightest ice is on top, then the saltiest liquid is heavy enough to sink to the bottom. As the oceans churn and cold plumes snake around, ice in the uppermost ocean layer form in the seawater. When ice forms, salts precipitate out. The heavier salts would thus fall downward, and the lighter ice, or snow, would float upward. This snow melts again before reaching the top of the ocean, possibly leaving slush in the middle of the moon sandwich.
And if the first layer on top of the rocky core is salty water, that’s even better.
“This is good news for Ganymede,” said Vance. “Its ocean is huge, with enormous pressures, so it was thought that dense ice had to form at the bottom of the ocean. When we added salts to our models, we came up with liquids dense enough to sink to the sea floor.”
You can read more about their modeling here, and the research appears in the journal Planetary and Space Science. We’ll add a link to the paper when it becomes available.
NASA's Curiosity Mars rover has caught the first image of asteroids taken from the surface of Mars. The image includes two asteroids, Ceres and Vesta. This version includes Mars' moon Deimos in a circular, exposure-adjusted inset and square insets at left from other observations the same night. Credit: NASA/JPL-Caltech/MSSS/Texas A&M
NASA’s Curiosity Mars rover has caught the first image of asteroids taken from the surface of Mars on April 20, 2014. The image includes two asteroids, Ceres and Vesta. This version includes Mars’ moon Deimos in a circular, exposure-adjusted inset and square insets at left from other observations the same night. Credit: NASA/JPL-Caltech/MSSS/Texas A&M
More night sky views and surface mosaics below[/caption]
The Curiosity rover has captured the first images of asteroids even taken by a Human probe from the alien surface of the Red Planet during night sky imaging.
And it’s not just one asteroid, but two asteroids caught in the same night time pointing on the Red Planet. Namely, asteroids Ceres and Vesta.
The stupendous image – seen above – was snapped by Curiosity’s high resolution Mastcam camera earlier this week on Sunday, April 20, 2014, Sol 606, whilst she was scanning about during daylight for her next drilling target at “The Kimberley” waypoint she pulled into at the start of this month.
Ceres and Vesta appear as streaks since the Mastcam image was taken as a 12 second time exposure.
“This imaging was part of an experiment checking the opacity of the atmosphere at night in Curiosity’s location on Mars, where water-ice clouds and hazes develop during this season,” said camera team member Mark Lemmon of Texas A&M University, College Station, in a statement.
“The two Martian moons were the main targets that night, but we chose a time when one of the moons was near Ceres and Vesta in the sky.”
View our “Kimberley” region photo mosiacs below to see exactly from where the six wheeled robot took the asteroid image shown above, while driving around the base of “Mount Remarkable”.
And those two asteroids are extra special because not only are they the two most massive objects in the Main asteroid belt between Mars and Jupiter, but they are also the destinations of another superlative NASA unmanned mission – Dawn.
Curiosity Mars rover captured this panoramic view of a butte called “Mount Remarkable” and surrounding outcrops at “The Kimberley ” waypoint on April 11, 2014, Sol 597. Colorized navcam photomosaic was stitched by Marco Di Lorenzo and Ken Kremer. Credit: NASA/JPL-Caltech/Marco Di Lorenzo/Ken Kremer – kenkremer.com
The exotic Dawn probe, propelled by a stream of ions, orbited Vesta for a year in 2011 and is now approaching Ceres for an exciting orbital mission in 2015.
Ceres, the largest asteroid, is about 590 miles (950 kilometers) in diameter. Vesta is the third-largest object in the main belt and measures about 350 miles (563 kilometers) wide.
And as if Curiosity’s mouthwatering and heavenly double asteroid gaze wasn’t already spectacular enough, the tinier of Mars’ moons, Deimos, was also caught in that same image.
A trio of star trails is also seen, again due to the 12 second time exposure time.
Furthermore, Mars largest moon Phobos as well as massive planets Jupiter and Saturn were also visible that same Martian evening, albeit in a different pointing.
These celestial objects are all combined in the composite image above.
“The background is detector noise, limiting what we can see to magnitude 6 or 7, much like normal human eyesight. The two asteroids and three stars would be visible to someone of normal eyesight standing on Mars. Specks are effects of cosmic rays striking the camera’s light detector,” says NASA.
An unannotated image is seen below.
NASA’s Curiosity Mars rover has caught the first image of asteroids taken from the surface of Mars. The image includes two asteroids, Ceres and Vesta. In this unannotated version of the 12-second-exposure image, the brightness of Deimos at lower right saturates the image, making the moon appear overly large. Credit: NASA/JPL-Caltech/MSSS/Texas A&M
Curiosity’s makers back on Earth are nowhere to be seen. But check out the Curiosity’s earlier photo below of the Earth and Moon from my prior article – here.
To date, Curiosity’s odometer totals 3.8 miles (6.1 kilometers) since landing inside Gale Crater on Mars in August 2012. She has taken over 143,000 images.
The sedimentary foothills of Mount Sharp, which reaches 3.4 miles (5.5 km) into the Martian sky, is the 1 ton robots ultimate destination inside Gale Crater because it holds caches of water altered minerals. Such minerals could possibly indicate locations that sustained potential Martian life forms, past or present, if they ever existed. Martian landscape with rows of curved rock outcrops at ‘Kimberly’ in the foreground and spectacular Mount Sharp on the horizon. NASA’s Curiosity Mars rover pulled into Kimberly waypoint dominated by layered rock outcrops as likely drilling site. This colorized navcam camera photomosaic was assembled from imagery taken on Sol 576 (Mar. 20, 2014). Credit: NASA/JPL-Caltech/Marco Di Lorenzo/Ken Kremer-kenkremer.com
Curiosity has some 4 kilometers to go to reach the base of Mount Sharp sometime later this year.
Stay tuned here for Ken’s continuing Curiosity, Opportunity, Chang’e-3, SpaceX, Orbital Sciences, LADEE, MAVEN, MOM, Mars and more planetary and human spaceflight news.
You are here! – As an Evening Star in the Martian Sky
This evening-sky view taken by NASA’s Mars rover Curiosity shows the Earth and Earth’s moon as seen on Jan. 31, 2014, or Sol 529 shortly after sunset at the Dingo Gap inside Gale Crater. Credit: NASA/JPL-Caltech/MSSS/TAMUMars rock rows and Mount Sharp. Martian landscape scene with rows of striated rocks in the foreground and Mount Sharp on the horizon. NASA’s Curiosity Mars rover paused mid drive at the Junda outcrop to snap the component images for this navcam camera photomosaic on Sol 548 (Feb. 19, 2014) and then continued traveling southwards towards mountain base. UHF Antenna at right. Credit: NASA/JPL-Caltech/Marco Di Lorenzo/Ken Kremer-kenkremer.com
A full view of Jupiter on February 25, 2014 showing several features including three storms that in combination look like Mickey Mouse. Credit and copyright: Damian Peach.
We told you this was going to be a good season to observe Jupiter, and astrophotographers in the northern hemisphere have been making the most of this time of opposition where Jupiter has been riding high in the sky. What we didn’t know was that there was going to be a familiar face staring back at us.
A combination of three storms has been noted throughout this Jupiter observing season for its resemblance to Mickey Mouse’s face (at least in outline), and astrophotographer Damian Peach has captured some great images of these storms, along with the iconic Great Red Spot, its little brother Oval BA and other turbulence. Damian has also put together a stunning movie (below) showing about three hours of rotation of the king of the planets.
Damian explained the Mickey Mouse storms are two anticyclones (high pressure regions) that form the ears while a longer elongated cyclone (low pressure) forms the face.
The abundance of storms on Jupiter are a result of the planet’s dense atmosphere of hydrogen and helium and large gravitational field. Storms on this planet are likely the strongest in the Solar System.
Jupiter reached its most northern point for 2014 at a declination of +23.3 degrees on March 11, but it’s still easily visible since it is the brightest starlike object in the evening sky.
Jupiter’s Great Red Spot and the ‘Mickey Mouse’ storms on February 25, 2014. Credit and copyright: Damian Peach.More images of Jupiter on February 25, 2014, with these showing the Oval BA storm, with the Mickey Mouse storms peeking around the left side. Credit and copyright: Damian Peach.
As David Dickinson mentioned in his article on observing Jupiter, we’re also in the midst of a plane crossing, as the orbits of the Jovian moons appear edge-on to our line of sight throughout 2014 and into early 2015.
Damian captured this great transit of Europa earlier in February:
Illustration of the twin Van Allen Probes (formerly Radiation Belt Storm Probes) in orbit (JHUAPL/NASA)
Earth’s inner radiation belt displays a curiously zebra-esque striped pattern, according to the latest findings from NASA’s twin Van Allen Probes. What’s more, the cause of the striping seems to be the rotation of the Earth itself — something that was previously thought to be impossible.
“…it is truly humbling, as a theoretician, to see how quickly new data can change our understanding of physical properties.”
– Aleksandr Ukhorskiy, Johns Hopkins University Applied Physics Laboratory
Our planet is surrounded by two large doughnut-shaped regions of radiation called the Van Allen belts, after astrophysicist James Van Allen who discovered their presence in 1958. (Van Allen died at the age of 91 in 2006.) The inner Van Allen belt, extending from about 800 to 13,000 km (500 to 8,000 miles) above the Earth, contains high-energy electrons and protons and poses a risk to both spacecraft and humans, should either happen to spend any substantial amount of time inside it.
The Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) is a time-of-flight versus energy spectrometer (JHUAPL)
Launched aboard an Atlas V rocket from Cape Canaveral AFS on the morning of Aug. 30, 2012, the Van Allen Probes (originally the Radiation Belt Storm Probes) are on a two-year mission to investigate the belts and find out how they behave and evolve over time.
One of the instruments aboard the twin probes, the Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE), has detected a persistent striped pattern in the particles within the inner belt. While it was once thought that any structures within the belts were the result of solar activity, thanks to RBSPICE it’s now been determined that Earth’s rotation and tilted magnetic axis are the cause.
“It is because of the unprecedented high energy and temporal resolution of our energetic particle experiment, RBSPICE, that we now understand that the inner belt electrons are, in fact, always organized in zebra patterns,” said Aleksandr Ukhorskiy of the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Md., co-investigator on RBSPICE and lead author of the paper. “Furthermore, our modeling clearly identifies Earth’s rotation as the mechanism creating these patterns. It is truly humbling, as a theoretician, to see how quickly new data can change our understanding of physical properties.”
The model of the formation of the striped patterns is likened to the pulling of taffy.
RBSPICE data of stripes within the inner Van Allen belt (Click for animation) Credit: A. Ukhorskiy/JHUAPL
“If the inner belt electron populations are viewed as a viscous fluid,” Ukhorskiy said, “these global oscillations slowly stretch and fold that fluid, much like taffy is stretched and folded in a candy store machine.”
“This finding tells us something new and important about how the universe operates,” said Barry Mauk, a project scientist at APL and co-author of the paper. “The new results reveal a new large-scale physical mechanism that can be important for planetary radiation belts throughout the solar system. An instrument similar to RBSPICE is now on its way to Jupiter on NASA’s Juno mission, and we will be looking for the existence of zebra stripe-like patterns in Jupiter’s radiation belts.”
Jupiter’s Van Allen belts are similar to Earth’s except much larger; Jupiter’s magnetic field is ten times stronger than Earth’s and the radiation in its belts is a million times more powerful (source). Juno will arrive at Jupiter in July 2016 and spend about a year in orbit, investigating its atmosphere, interior, and magnetosphere.
Thanks to the Van Allen Probes. Juno now has one more feature to look for in Jupiter’s radiation belts.
“It is amazing how Earth’s space environment, including the radiation belts, continue to surprise us even after we have studied them for over 50 years. Our understanding of the complex structures of the belts, and the processes behind the belts’ behaviors, continues to grow, all of which contribute to the eventual goal of providing accurate space weather modeling.”
– Louis Lanzerotti, physics professor at the New Jersey Institute of Technology and principal investigator for RBSPICE
The Van Allen Probes are the second mission in NASA’s Living With a Star program, managed by NASA’s Goddard Space Flight Center in Greenbelt, MD. The program explores aspects of the connected sun-Earth system that directly affect life and society.
Artist's impression of 624 Hektor, the largest known Trojan asteroid. The dual asteroid is 155 miles (250 kilometers) at its widest. It also has a 7.5-mile (12-mile) moon. Credit: H. Marchis/F. Marchis
Two icy asteroids could have crashed into each other early in the solar system’s history to form the strange-looking 624 Hektor, new research reveals. The 155-mile (250-kilometer) asteroid is the largest known Trojan asteroid, or space rock that follows along with Jupiter in the gas giant’s orbital path.
Hektor also has a moon, which was first discovered in 2006 by another team led by the same lead author, the SETI Institute’s Franck Marchis. It’s taken the astronomers about eight years to get a handle on the complex orbit of the system, a topic that the new research examines in detail. That was partly because the path was so “bizarre”, the team stated, and also because time on the W.M. Keck Observatory telescopes (used to perform the observations) is limited. There are few other observatories that could do the same work, the team added.
The moon, which is about 7.5 miles or 12 kilometers in diameter, orbits its parent asteroid every three days. The moon’s path is about 373 miles (600 km) distant and inclined almost at 45 degrees to the asteroid’s equator.
The Trojan asteroid 624 Hektor is visible in these two adaptive optics observations in July 2006 and October 2008, both performed with the W.M. Keck Observatory’s II telescope. Hektor is in the middle of each picture, and its moon in the circles. Credit: WMKO/Marchis
“The orbit of the moon is elliptical and tilted relative to the spin of Hektor, which is very different from other asteroids with satellites seen in the main-belt,” stated Matija Cuk, a paper co-author who is a scientist at the Carl Sagan Center of the SETI Institute. “However, we did computer simulations, which include Hektor being a spinning football shape asteroid and orbiting the Sun, and we found that the moon’s orbit is stable over billions of years.”
While the artist’s conception above shows Hektor as a peanut, the exact shape is still not known for sure. The models and the adaptive optics suggest that it is likely a dual-lobe asteroid. What is better known, however, is that the asteroid is “extremely elongated” and spins in less than seven hours.
The origin of the moon is unclear, but the researchers suggested it could be because of ejecta associated with the collision that formed the asteroid. They said more simulations are needed on that point. What’s more, Hektor has another mystery associated with its composition.
An artist’s rendering of a Kuiper Belt object. Image: NASA
“We also show that Hektor could be made of a mixture of rock and ices, similar to the composition of Kuiper belt objects, Triton and Pluto. How Hektor became a Trojan asteroid, located at only 5 times the Earth–Sun distance, is probably related to the large scale reshuffling that occurred when the giant planets were still migrating,” stated Julie Castillo-Rogez, a researcher at NASA’s Jet Propulsion Laboratory who participated in the research.
You can read more about the research in Astrophysical Journal Letters. By the way, the moon does not have a name yet, and the researchers said they are looking for any ideas as long as it fulfills a couple of ideas: “the satellite should receive a name closely related to the name of the primary and reflecting the relative sizes between these objects.” Feel free to share your suggestions in the comments.
