Closest view of Saturn's moon Methone ever captured by Cassini
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While many of us here on Earth were waiting for the Moon to take a bite out of the Sun this past Sunday, Cassini was doing some moon watching of its own, 828.5 million miles away!
The image above is a color-composite raw image of Methone (pronounced meh-tho-nee), a tiny, egg-shaped moon only 2 miles (3 km) across. Discovered by Cassini in 2004, Methone’s orbit lies between Mimas and Enceladus, at a distance of 120,546 miles (194,000 km) from Saturn — that’s about half the distance between Earth and the Moon.
At an altitude of 1,200 miles (1900 km) this was Cassini’s closest pass ever of Methone, a rare visit that occurred after the spacecraft departed the much larger Tethys.
Along with sister moons Pallene and Anthe, Methone is part of a group called the Alkyonides, named after daughters of the god Alkyoneus in Greek mythology. The three moons may be leftovers from a larger swarm of bodies that entered into orbit around Saturn — or they may be pieces that broke off from either Mimas or Enceladus.
Earlier on Sunday, May 20, Cassini paid a relatively close visit to Tethys (pronounced tee-this), a 662-mile (1065-km) -wide moon made almost entirely of ice. One of the most extensively cratered worlds in the Solar System, Tethys’ surface is dominated by craters of all sizes — from the tiniest to the giant 250-mile (400-km) -wide Odysseus crater — as well as gouged by the enormous Ithaca Chasma, a series of deep valleys running nearly form pole to pole.
Saturn's icy moon Tethys with Ithaca Chasma visible, seen by Cassini on May 20, 2012.Tethys' rugged and heavily-cratered surface near the terminatorCassini looks down into the 62 mile (100 km) wide Ithaca Chasma
Cassini passed within 34,000 miles (54,000 km) of Tethys on May 20, before heading to Methone and then moving on to its new path toward Titan, a trajectory that will eventually take it up out of Saturn’s equatorial plane into a more inclined orbit in order to better image details of the rings and Saturn’s poles.
Read more about this flyby on the Cassini mission site here. and see more raw images straight from the spacecraft on the CICLOPS imaging lab site here.
Image credit: NASA / JPL / Space Science Institute. (Color-composite image edited by J. Major.)
Junocam image of the stars that make up the "Big Dipper" asterism
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All right, it may look just like any other picture you’ve ever seen of the Big Dipper. Maybe even a little less impressive, in fact. But, unlike any other picture, this one was taken from 290 million km away by NASA’s Juno spacecraft en route to Jupiter, part of a test of its Junocam instrument! Now that’s something new concerning a very old lineup of stars!
“I can recall as a kid making an imaginary line from the two stars that make up the right side of the Big Dipper’s bowl and extending it upward to find the North Star,” said Scott Bolton, principal investigator of NASA’s Juno mission. “Now, the Big Dipper is helping me make sure the camera aboard Juno is ready to do its job.”
Diagram of the Juno spacecraft (NASA/JPL)
The image is a section of a larger series of scans acquired by Junocam between 20:23 and 20:56 UTC (3:13 to 3:16 PM EST) on March 14, 2012. Still nowhere near Jupiter, the purpose of the imaging exercise was to make sure that Junocam doesn’t create any electromagnetic interference that could disrupt Juno’s other science instruments.
In addition, it allowed the Junocam team at Malin Space Science Systems in San Diego, CA to test the instrument’s Time-Delay Integration (TDI) mode, which allows image stabilization while the spacecraft is in motion.
Because Juno is rotating at about 1 RPM, TDI is crucial to obtaining focused images. The images that make up the full-size series of scans were taken with an exposure time of 0.5 seconds, and yet the stars (brightened above by the imaging team) are still reasonably sharp… which is exactly what the Junocam team was hoping for.
“An amateur astrophotographer wouldn’t be very impressed by these images, but they show that Junocam is correctly aligned and working just as we expected”, said Mike Caplinger, Junocam systems engineer.
As well as the Big Dipper, Junocam also captured other stars and asterisms, such as Vega, Canopus, Regulus and the “False Cross”. (Portions of the imaging swaths were also washed out by sunlight but this was anticipated by the team.)
These images will be used to further calibrate Junocam for operation in the low-light environment around Jupiter, once Juno arrives in July 2016.
Read more about the Junocam test on the MSSS news page here.
As of May 10, Juno was approximately 251 million miles (404 million kilometers) from Earth. Juno has now traveled 380 million miles (612 million kilometers) since its launch on August 5, 2011 and is currently traveling at a velocity of 38,300 miles (61,600 kilometers) per hour relative to the Sun.
"Hopper" rover/spacecraft concept by Stanford University's Marco Pavone
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With all there’s yet to learn about our solar system from the many smaller worlds that reside within it — asteroids, protoplanets and small moons — one researcher from Stanford University is suggesting we unleash a swarm of rover/spacecraft hybrids that can explore en masse.
Marco Pavone, an assistant professor of aeronautics and astronautics at Stanford University and research affiliate at JPL, has been developing a concept under NASA’s Innovative Advanced Concepts (NIAC) Program that would see small spherical robots deployed to small worlds, such as Mars’ moons Phobos and Deimos, where they would take advantage of low gravity to explore — literally — in leaps and bounds.
Due to the proposed low costs of such a mission, multiple spacecraft could be scattered across a world, increasing the area that could be covered as well as allowing for varied surfaces to be explored. Also, were one spacecraft to fail the entire mission wouldn’t be compromised.
The concept is similar to what NASA has done in the past with the Mars rovers, except multiplied in the number of spacecraft (and reduced in cost.)
The robots would be deployed from a “mother” spacecraft and spring into action upon landing, tumbling, hopping and vaulting their way across low-mass worlds.
In addition to providing our first views from the surfaces of such worlds, Pavone’s hybrid rovers could also help prepare for future, more in-depth exploration.
“The systematic exploration of small bodies would help unravel the origin of the solar system and its early evolution, as well as assess their astrobiological relevance,” Pavone explains. “In addition, we can evaluate the resource potential of small bodies in view of future human missions beyond Earth.”
Read more from NASA’s Office of the Chief Technologist here.
For a quarter century, researchers believed a bow "shock" formed ahead of the heliosphere as it moved through interstellar space – similar to the sonic boom made by a jet breaking the sound barrier. New data from NASA's Interstellar Boundary Explorer (IBEX) shows that the heliosphere moves through space too slowly to form a bow shock. Credit: Southwest Research Institute.
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For years, scientists have thought a bow “shock” formed ahead of our solar system’s heliosphere as it moved through interstellar space – similar to the sonic boom made by a jet breaking the sound barrier. But new data from NASA’s Interstellar Boundary Explorer (IBEX) shows that our system and its heliosphere move through space too slowly to form a bow shock, and therefore does not exist. Instead there is a more gentle ‘wave.’
“While bow shocks certainly exist ahead of many other stars, we’re finding that our Sun’s interaction doesn’t reach the critical threshold to form a shock,” said Dr. David McComas, principal investigator of the IBEX mission, “so a wave is a more accurate depiction of what’s happening ahead of our heliosphere — much like the wave made by the bow of a boat as it glides through the water.”
From IBEX data, McComas and his team were able to make refinements in relative speed of our system, as well as finding more information about the local interstellar magnetic field strength. IBEX data have shown that the heliosphere actually moves through the local interstellar cloud at about 52,000 miles per hour, roughly 7,000 miles per hour slower than previously thought. That is slow enough to create more of a bow “wave” than a shock.
Bow shocks exist around other astrospheres, as seen in these images taken by multiple telescopes. New IBEX data show that our heliosphere moves through interstellar space too slowly to produce a bow shock, creating more of a “wake” as it travels through space. Image courtesy of Southwest Research Institute
Another influence is the magnetic pressure in the interstellar medium. IBEX data, as well as earlier Voyager observations, show that the magnetic field is stronger in the interstellar medium requiring even faster speeds to produce a bow shock. Combined, both factors now point to the conclusion that a bow shock is highly unlikely.
The IBEX team combined its data with analytical calculations and modeling and simulations to determine the conditions necessary for creating a bow shock. Two independent global models — one from a group in Huntsville, Ala., and another from Moscow — correlated with the analytical findings.
Their paper was published today in the journal Science.
How does this new finding change our understanding of our heliosphere?
“It’s too early to say exactly what this new data means for our heliosphere,” McComas said. “Decades of research have explored scenarios that included a bow shock. That research now has to be redone using the latest data. Already, we know there are likely implications for how galactic cosmic rays propagate around and enter the solar system, which is relevant for human space travel.”
Astronomers have found four nearby white dwarf stars surrounded by disks of material that could be the remains of rocky planets much like Earth — and one star in particular appears to be in the act of swallowing up what’s left of an Earthlike planet’s core.
The research, announced today by the Royal Astronomical Society, gives a chilling look at the eventual fate that may await our own planet.
Astronomers from the University of Warwick used Hubble to identify the composition of four white dwarfs’ atmospheres, found during a survey of over 80 such stars located within 100 light-years of the Sun. What they found was a majority of the material was composed of elements found in our own Solar System: oxygen, magnesium, silicon and iron. Together these elements make up 93% of our planet.
In addition, a curiously low ratio of carbon was identified, indicating that rocky planets were at one time in orbit around the stars.
Since white dwarfs are the leftover cores of stellar-mass stars that have burnt through all their fuel, the material in their atmosphere is likely the leftover bits of planets. Once held in safe, stable orbits, when their stars neared the ends of their lives they expanded, possibly engulfing the innermost planets and disrupting the orbits of others, triggering a runaway collision effect that eventually shattered them all, forming an orbiting cloud of debris.
This could very well be what happens to our Solar System in four or five billion years.
“What we are seeing today in these white dwarfs several hundred light years away could well be a snapshot of the very distant future of the Earth,” said Professor Boris Gänsicke of the Department of Physics at the University of Warwick, who led the study. “During the transformation of the Sun into a white dwarf, it will lose a large amount of mass, and all the planets will move further out. This may destabilise the orbits and lead to collisions between planetary bodies as happened in the unstable early days of our solar systems.”
One of the white dwarfs studied, labeled PG0843+516, may even be actively eating the remains of an once-Earthlike world’s core.
The researchers identified an abundance of heavier elements like iron, nickel and sulphur in the atmosphere surrounding PG0843+516. These elements are found in the cores of terrestrial planets, having sunk into their interiors during the early stages of planetary formation. Finding them out in the open attests to the destruction of a rocky world like ours.
Of course, being heavier elements, they will be the first to be accreted by their star.
“It is entirely feasible that in PG0843+516 we see the accretion of such fragments made from the core material of what was once a terrestrial exoplanet,” Prof. Gänsicke said.
It’s an eerie look into a distant future, when Earth and the inner planets could become just some elements in a cloud.
Galileo image of Ganymede, Jupiter's - and the Solar System's - largest moon. (Ted Stryk)
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The European Space Agency has given the go-ahead for an exciting mission to explore the icy moons of Jupiter, as well as the giant planet itself.
JUICE — JUpiter ICy moons Explorer — will consist of a solar-powered spacecraft that will spend 3.5 years within the Jovian system, investigating Ganymede, Europa and the upper atmosphere of Jupiter. Anticipated to launch in June 2022, JUICE would arrive at Jupiter in early 2030.
As its name implies, JUICE’s main targets are Jupiter’s largest icy moons — Ganymede and Europa — which are thought to have liquid oceans concealed beneath their frozen surfaces.
The largest moon in the Solar System, Ganymede is also thought to have a molten iron core generating a magnetic field much like Earth’s. The internal heat from this core may help keep Ganymede’s underground ocean liquid, but the dynamics of how it all works are not quite understood.
JUICE will also study the ice-coated Europa, whose cueball-smooth surface lined with cracks and jumbled mounds of frozen material seem to be sure indicators of a subsurface ocean, although how deep and how extensive is might be are still unknown — not to mention its composition and whether or not it could be hospitable to life.
The rust-colored cracks lining Europa's otherwise smooth surface hint at a subsurface ocean. (Ted Stryk)
“JUICE will give us better insight into how gas giants and their orbiting worlds form, and their potential for hosting life,” said Professor Alvaro Giménez Cañete, ESA’s Director of Science and Robotic Exploration.
The JUICE spacecraft was originally supposed to join a NASA mission dedicated to the investigation of Europa, but NASA deemed their proposed mission too costly and it was cancelled. According to Robert Pappalardo, study scientist for the Europa mission based at JPL, NASA may still supply some instruments for the spacecraft “assuming that the funding situation in the United States can bear it.”
Artist's rendering of JUICE at Jupiter. (ESA/AOES)
JUICE will also capture images of Jupiter’s moon Callisto and search for aurorae in the gas giant’s upper atmosphere, as well as measure the planet’s powerful magnetic field. Once arriving in 2030, it will spend at least three years exploring the Jovian worlds.
Read more in today’s news release from Nature, and stay tuned to ESA’s JUICE mission page here.
OMG Space attempts to portray the scale sizes and distances in the Solar System
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“You may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space.” – Douglas Adams
Standard classroom models and textbook illustrations of the Solar System, regardless of how pretty they are, all share one thing in common: they’re wrong. Ok, maybe not wrong, but definitely inaccurate… especially in regards to scale. And understandably so, as it’s nearly impossible to portray in a convenient manner the sheer amount of space there is between the planets and their relative sizes. Even if a model manages to show one or the other in a straightforward, linear fashion, it usually doesn’t show both.
This one does.
OMG Space is a web page made by Margot Trudell as graphic design thesis project at Toronto’s OCAD University. Displayed on the Visual.ly portfolio site, Margot’s expansive infographic shows the Sun, planets and some minor bodies to scale, both in terms of relative size and distance. By clicking on a planet’s name at the bottom of the page you’ll be whisked away toward it, giving a sense of how very far it really is between the many worlds that make up our own little Solar System.
And if that’s not enough, Margot has included a descriptive chart for each world that gives basic information on distance from the Sun, orbital period and moon count as well as details on visiting exploration missions — past, present and planned. These can be accessed by clicking on the respective worlds once you arrive.
Each planet has an infographic associated with it, showing physical characteristics and exploration timelines. (M. Trudell)
“I created the infographics first and as I worked on them decided they needed more context, and the idea of creating a to scale version of our solar system came to mind,” Margot told Universe Today. “The project was initially intended to be all print, but knowing the real scale of our solar system I eventually came up with the idea of using the infiniteness of the web to my advantage.”
If you watch the scroll bar on the right side of the page (and I do suggest resizing the page to fill your screen as much as possible) you’ll also get a sense of how much space you’re traversing as you zip between worlds. And that’s just taking into consideration the average distances between each planet at opposition. In reality, they’re never lined up in a row like that!
If you’re so inclined you can also scroll up and down manually… if only to see how long it takes you to not get anywhere.
“My favourite thing to do on OMG Space’s website is go to Earth and then click on the link to the Moon,” Margot said. “The small distance you move yet the big gap you see… it gives you a whole new perspective on how far people traveled to get to the moon and back, and it shows how far the moon really is from Earth (I feel that it’s always portrayed as being almost right beside us) and makes you consider how powerful those rockets must have been to get us that far.
“It gives you a bit of that ‘OMG’ feeling that the project is named for.”
Yes, OMG indeed.
Infographics by Margot Trudell. See more of Margot’s work here.
Color-composite image of Phoebe as seen by Cassini in 2009.
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Saturn’s curious moon Phoebe features a heavily-cratered shape and orbits the ringed planet backwards at a considerable distance of over 8 million miles (12.8 million km). According to recent news from the Cassini mission Phoebe may actually be a Kuiper Belt object, having more in common with planets than it does with any of Saturn’s other satellites.
132 miles (212 km) in diameter, Phoebe is the largest of Saturn’s irregular moons — a cloud of small, rocky worlds held in distant orbits at highly inclined paths. Its backwards (retrograde) motion around Saturn and dense composition are dead giveaways that it didn’t form in situ within the Saturnian system, but rather was captured at some point when it strayed too close to the gas giant.
In fact it’s now thought that Phoebe may be a remnant from the formation of the Solar System — a planetesimal — with its own unique history predating its adoption into Saturn’s extended family of moons.
“Unlike primitive bodies such as comets, Phoebe appears to have actively evolved for a time before it stalled out,” said Julie Castillo-Rogez, a planetary scientist at NASA’s Jet Propulsion Laboratory. “Objects like Phoebe are thought to have condensed very quickly. Hence, they represent building blocks of planets. They give scientists clues about what conditions were like around the time of the birth of planets and their moons.”
Although Phoebe is heavily eroded and irregularly-shaped today at one time it may have been much rounder. But an early composition of radioactive elements would have generated heat, and as it warmed it “deflated” through compression, growing denser and denser.
Map of Phoebe's surface. (NASA/JPL-Caltech/SSI/Cornel)
Now, Phoebe exhibits a similar density to Pluto — another denizen of the Kuiper Belt.
At some point Phoebe may even have had water, kept liquid by its radioactive heat. That is, until the heat faded and it froze, creating the icy surface detected by Cassini’s instruments.
Still, Cassini’s study of Saturn’s moons has provided scientists with clues to what was happening much earlier on in the Solar System. What caused Phoebe to drift inwards to be caught up in orbit around Saturn? How did it survive such a supposed shuffling of planets and other worlds did not? As Cassini continues its investigation answers — and undoubtedly even more questions — will be uncovered.
Video Caption: This mesmerizing video unveils incredibly amazing sequences around Jupiter and Saturn from NASA’s Cassini and Voyager missions set to stirring music by “The Cinematic Orchestra -That Home (Instrumental)”. Credit: Sander van den Berg
Don’t hesitate 1 moment ! Look and listen to this mind blowing video of the Jupiter and Saturnian systems.
Discovery and Enterprise rest nose-to-nose at ceremony transferring ownership of Discovery from NASA to the Smithsonian National Air & Space Museum on April 19, 2012. The official deed transfer ceremony took place at the Steven F. Udvar-Hazy Center in Chantilly, Virginia. Credit: Ken Kremer
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Space Shuttle Discovery, the longest serving and most flown spaceship in human history, entered her eternal home today, Thursday, April 19, at the Smithsonian’s National Air & Space Museum Annex in Virginia.
Discovery thereby assumed her new status as a museum relic and monument to the promise and glorious dreams of space exploration, inspiring future generations of explorers to reach far beyond their grasp and accomplish the unthinkable. That’s what space and science are all about.
The space shuttle program and all three of NASA’s winged spaceships were forcibly retired by politicians at the conclusion of the final shuttle mission, STS-135, in July 2011 which left America with no means to launch our own astronauts into space and to the International Space Station.
Shuttle astronauts march with Discovery being towed from Dulles to the Smithsonian’s Udvar Hazy Center on April 19, 2012. Credit: Ken Kremer
Discovery officially became the property of the Smithsonian Museum when NASA Administrator Charles Bolden signed the title of ownership over from NASA to the world renowned museum at a public ceremony held today at the Smithsonian’s Steven F. Udvar-Hazy Center in Chantilly, Virginia.
“Today, while we look back at Discovery’s amazing legacy, I also want to look forward to what she and the shuttle fleet helped to make possible,” said NASA Administrator Charles Bolden. “As NASA transfers the shuttle orbiters to museums across the country, we are embarked on an exciting new space exploration journey. Relying on American ingenuity and know-how, NASA is partnering with private industry to provide crew and cargo transportation to the International Space Station, while developing the most powerful rocket ever built to take the nation farther than ever before into the solar system.”
National Air and Space Museum Director, General John “Jack” Dailey said, “Discovery has distinguished itself as the champion of America’s shuttle fleet. In its new home, it will shine as an American icon, educating and inspiring people of all ages for generations to come. The Museum is committed to teaching and inspiring youngsters, so that they will climb the ladder of academic success and choose professions that will help America be competitive and successful in the world of tomorrow.”
Bolden and Dailey signed the transfer documents in front of the huge crowd who came to celebrate Discovery’s arrival.
Shuttle astronauts march with Discovery being towed from Dulles to the Smithsonian’s Udvar Hazy Center on April 19, 2012. Credit: Ken Kremer
The official handover ceremony was witnessed by a prestigious gathering of some three dozen astronauts including more than a dozen men and women who served as Commanders of Space Shuttle Discovery and Senator and Astronaut John Glenn, the first American to orbit the Earth 50 years ago in 1962.
Glenn flew to space for the 2nd time aboard Discovery as a payload specialist in 1998 at the age of 77. He is the oldest person to fly in space.
Shuttle astronauts march with Discovery being towed to the Smithsonian’s Udvar-Hazy Center and official Welcome ceremony on April 19, 2012. Credit: Ken Kremer
And the general public showed their enthusiastic support for NASA and space exploration by attending in the thousands and staying all day for the dozens of activity stations, presentations and displays organized by NASA and the Smithsonian and its donors.
Glenn made clear his disagreement with the end of NASA’s shuttle program.
Discovery arrives at her final resting place in the Smithsonian on April 19, 2012. Credit: Ken Kremer
To make way for Discovery, Space Shuttle Enterprise was first towed out a huge rear door of the museum early this morning. Discovery and Enterprise then met nose to nose as the dramatic backdrop for the official welcoming ceremony.
Late this afternoon, Discovery was towed to her final resting place into the museum to the exact spot formerly held by Enterprise, which had been on display at the Virginia facility since 2003.
Altogether, Discovery flew 39 missions and spent a full year (365 days) in space, orbited Earth 5,830 times and traveled 148,221,675 miles during a space flight career spanning 27 years.
Discovery flew its maiden voyage on Aug. 30, 1984 and blasted off on her final voyage on Feb. 24, 2011. The STS-133 mission was the final flight for the illustrious orbiter which landed at the Kennedy Space Center on March 9, 2012.
Discovery deployed the iconic Hubble Space Telescope to orbit, one of the premier science instruments built by humankind. Discovery delivered many other science payloads to orbit and also to explore the solar system, including the Ulysses solar probe.
The winged spaceship was NASA’s fleet leading orbiter and played a significant role in building the International Space Station and visiting the Russian Mir Space Station.
