John Williams is owner of TerraZoom, a Colorado-based web development shop specializing in web mapping and online image zooms. He also writes the award-winning blog, StarryCritters, an interactive site devoted to looking at images from NASA's Great Observatories and other sources in a different way. A long-time science writer and space enthusiast, he created award-winning Hubble Star Cards. Use coupon code UNIVERSE to Hold the Universe in your hands. Follow John on Twitter @terrazoom.
Imagine this “Death from the Skies” scenario; a tiny supernova lurks unseen near our Sun. Astronomers from the Harvard-Smithsonian Center for Astrophysics (CfA) announced the discovery of just such an object today and while it is not nearby, this new kind of supernova is so faint it has been hiding in the shadows.
Until now, supernovae have come in two main versions. In one scenario, a huge star, 10 to 100 times more massive as our Sun, collapses causing a colossal stellar explosion. Another scenario, known as Type Ia supernovae, occurs when material from a parent star streams onto the surface of a white dwarf. Over time, so much material falls onto the white dwarf that it raises the core temperature igniting carbon and causing a runaway fusion reaction. This event completely disrupts the white dwarf and results in a colossal stellar explosion.
Now astronomers have found a third type that is fainter and less energetic than a Type Ia. Called a Type Iax supernova, it is “essentially a mini supernova,” says lead author of the study Ryan Foley, Clay Fellow at the Harvard-Smithsonian Center for Astrophysics (CfA). “It’s the runt of the supernova litter.”
Being only about one-hundredth as bright as their supernova siblings, Foley calculates that Type Iax supernovae are about as third as common as Type Ia supernovae. The researchers also did not find them in elliptical galaxies, filled with older stars, suggesting that Type Iax supernovae come from young star systems.
So far, Foley and his team identified 25 examples of this new type of supernova. Based on observations, the team found that the new Type Iax supernovae come from binary star systems containing a white dwarf and a companion star that has burned all of its hydrogen, leaving an outer layer that is helium rich.
In a press release, Foley says they are not sure what triggers the Type Iax supernova. One explanation involves the ignition of the outer helium layer from the companion star. The resulting shockwave slams into the white dwarf and disrupts it, causing the explosion. Alternately, the white dwarf might ignite first due to the overlying helium shell it has collected from the companion star.
“Either way, it appears that in many cases the white dwarf survives the explosion unlike in a Type Ia supernova where the white dwarf is completely destroyed,” says Foley. “The star will be battered and bruised but it might live to see another day.”
Supernovae explosions release so much energy as heat and light that they outshine entire galaxies for brief periods of time. The extremely hot conditions naturally create new heavier elements, such as gold, lead, nickel, zinc and copper. The explosion enriches the surrounding area leaving material for new stars to form.
“Type Iax supernovas aren’t rare, they’re just faint,” explains Foley. “For more than a thousand years, humans have been observing supernovas. This whole time, this new class has been hiding in the shadows.”
This research has been accepted for publication in The Astrophysical Journal and is available online.
Like archaeologists sifting through the dust of ancient civilizations, scientists with the ESA Planck mission today showed a map of the oldest light in the Universe. The first cosmology results of the mission suggest our Universe is slightly older and expanding more slowly than previously thought.
Planck’s new estimate for the age of the Universe is 13.82 billion years.
The map also appears to show more matter and dark matter and less dark energy, a hypothetical force that is causing an expansion of the Universe.
“We are measuring the oldest light in the Universe, the cosmic microwave background,” says Paul Hertz, director of astrophysics with NASA. “It is the most sensitive and detailed map ever. It’s like going from standard television to a new high definition screen. The new details have become crystal clear.”
Overall, the cosmic background radiation, the afterglow of the Universe’s birth, is smooth and uniform. The map, however, provides a glimpse of the tiny temperature fluctuations that were imprinted on the sky when the Universe was just 370,000 years old. Scientists believe the map reveals a fossil, an imprint, of the state of the Universe just 10 nano-nano-nano-nano seconds after the Big Bang; just a tiny fraction of the time it took to read that sentence. The splotches in the Planck map represent the seeds from which the stars and galaxies formed.
The colors in the map represent different temperatures; red for warmer, blue for cooler. The temperature differences being only 1/100 millionth of a degree. “The contrast on the map has been turned way up,” says Charles Lawrence, the US project scientist for Planck at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
Planck, launched in 2009 from the Guiana Space Center in French Guiana, is a European Space Agency mission with significant contribution from NASA. The two-ton spacecraft gathers the ancient glow of the Universe’s beginning from a vantage more than 1 million miles from Earth.
This is not the first map produced by Planck. In 2010, Planck produced an all-sky radiation map. Scientists, using supercomputers, have removed not only the bright emissions from foreground sources, like the Milky Way, but also stray light from the satellite itself.
As the light travels, matter scattered throughout the Universe with its associated gravity subtly bends and absorbs the light, “making it wiggle to and fro,” said Martin White, a Planck project scientist with the University of California, Berkeley and the Lawrence Berkeley National Laboratory.
“The Planck map shows the impact of all matter back to the edge of the Universe,” says White. “It’s not just a pretty picture. Our theories on how matter forms and how the Universe formed match spectacularly to this new data.”
“This is a treasury of scientific data,” said Krzysztof Gorski, a member of the Planck team with JPL. “We are very excited with the results. We find an early Universe that is considerably less rigged and more random than other, more complex models. We think they’ll be facing a dead-end.”
An artists animation depicting the “life” of a photon, or a particle light, as it travels across space and time from the beginning of the Universe to the detectors of the Planck telescope. Credit: NASA
Planck scientists believe the new data should help scientists refine many of the theories proposed by cosmologists that the Universe underwent a sudden and rapid inflation.
NASA’s Super-TIGER science balloon landed Friday at a frigid and remote base in Antarctica after setting two duration records while gathering data about cosmic rays. There’s so much data that it will take scientists about two years to analyze, according to NASA.
Launched December 8, 2012 from the Long Duration Balloon site near McMurdo Station in Antarctica, the Super Trans-Iron Galactic Element Recorder balloon spent 55 days, 1 hour and 34 minutes aloft, shattering records previously set in 2009 by another NASA balloon for longest flight by a balloon of its size. The 39-million cubic foot balloon, spent most of its time cruising four times higher than commercial airlines at about 127,000 feet (almost 39 kilometers). The instrument is managed by Washington University in St. Louis, Missouri.
“Scientific balloons give scientists the ability to gather critical science data for a long duration at a very low relative cost,” said Vernon Jones, NASA’s Balloon Program scientist, in the press release. “Super-TIGER is scientific ballooning at its best.”
Super-TIGER measured rare heavy elements, such as iron, as they bombarded Earth from the Milky Way. The instrument detected about 50 million of these high-energy cosmic rays. Scientists hope the data from the mission will help understand where the energetic nuclei are produced and how they achieve such high energies.
NASA had three long-duration balloon missions in the summer skies of Antarctica. SuperTIGER was joined by BLAST and EBEX. All three balloons launched from the site near McMurdo Station in December. BLAST, or Balloon Borne Large Aperture Submillimeter Telescope launched Christmas Day and measured the polarized dust in star-forming regions helping astronomers determine if magnetic fields are a dominant force over turbulence in star-forming regions of the galaxy. BLAST’s mission lasted just over 16 days.
EBEX, the heaviest scientific payload borne aloft by a NASA balloon, measures cosmic microwave background radiation. The mission lasted 25 days and reached altitudes of 118,000 feet (or 36 kilometers).
Antarctica, it turns out, is ideal for these types of long-duration balloon missions with sparse populations and anticyclonic (east to west, counter-clockwise in the southern hemisphere) wind patterns in the stratosphere.
Each year, we are simply stunned by the beautiful images of space shot from a growing myriad of eyes that stare toward the heavens. This year was no different. From views out of the portholes of the International Space Station and landscapes of Vesta and Saturn to the faraway vistas from Hubble, Chandra and Spitzer sit back and stare in awe at the vastness of the cosmos with this look back at the most awesome space images of 2012
Image credit: NASA/JPL-Caltech/MSSS
Curiosity hams it up at “Rocknest” in Gale Crater on Mars. The car-sized rover used the Mars Hand Lens Imager (MAHLI) on October 31st and November 1st to capture dozens of high-resolution snapshots. This self-portrait shows the surrounding terrain including Gale Crater’s northern wall and Mount Sharp in the background. Read more about Curiosity’s Incredible Self-Portrait.
Image credit: NASA/SDO
A magnificent filament from a medium sized flare produced one of the best shows of 2012 for the Solar Dynamics Observatory. Some of the particles from this eruption smashed into Earth producing beautiful aurora. SDO also witnessed a celestial event that’s only happened seven times since the invention of the telescope; the transit of Venus across the Sun.
This mosaic from NASA’s Dawn spacecraft stitches together the best views of the asteroid Vesta. Highlights of the image include the towering south pole mountain – twice as high as Earth’s Mount Everest – and a set of three craters known as the “snowman” in the upper left of the image. Read more about Dawn’s parting shots of Vesta.
ESA Envisat MERIS
Released in 2012 but taken in 2011, ESA’s Envisat shows the amazing artwork that is Earth. This phytoplankton bloom swirls in the ocean currents creating a figure-8 pattern in the South Atlantic Ocean near the Falkland Islands. Read more.
A ‘Blue Marble’ image taken from NASA’s Suomi NPP Earth-observing satellite offers a snapshot of Earth’s surface on January 4, 2012. NASA released a night-time version called the ‘Black Marble’ in December 2012. The image at right features the threadlike connections of city lights across the eastern hemisphere. See more of the Black Marble images.
Astronauts aboard the International Space Station used their lofty perch to take some awesome images of Earth in 2012.
Expedition 33 crew look at exhaust trails from the Soyuz rocket that blasted off from the Baikonour Cosmodrome in October heading toward a rendezvous with the ISS. Exhaust plumes curled in different directions due to winds blowing in different directions as the rocket ascended through various atmospheric layers.
Astronauts shot an image of delicate shining threads called polar mesospheric clouds as they zoomed across the Tibetan plateau in June 2012. Also known as noctilucent or night-shining clouds, this image is the first time astronauts caught the phenomenon from orbit.
Sea ice forms along the Pacific coastline of the Kamchatka Peninsula in this image from Expedition 30 in March 2012. Large circular eddys spin off from the southwestward flowing Kamchatka current. While the sea ice looks thin and delicate, the smallest features in this image are several meters across. North is to the left in the image.
The ISS was sailing over Nova Scotia when astronauts caught sunglint reflecting off the Great Lakes of North America. Featured in the image are New York’s Finger Lakes, Lake Ontario, Lake Huron and Lake Erie. Most of Canada is hidden under a blanket of clouds toward the curving horizon in this image.
Image credit: ESO/VISTA/J. Emerson. Acknowledgment: Cambridge Astronomical Survey Unit
The European Southern Observatory’s Visible and Infrared Survey Telescope for Astronomy, or VISTA, captured what may be one of the most stunning images of the planetary nebula called the Helix Nebula, or NGC 7293.
Image credit: ESO/B. Bailleul
Thor’s Helmet Nebula, in Canis Major, was taken to celebrate the ESO’s 50th anniversary in October 2012. A bright massive star blew this colossal cosmic bubble in the surrounding nebula.
Image credit: ESO/T. Preibisch
ESO’s Very Large Telescope captured a vast panorama full of exotic cosmic landscapes, glowing gas and new stars in this image of the Carina Nebula.
NASA’s Hubble Space Telescope shot this most detailed view of the dusty core of Messier 82, or the Cigar Galaxy.
Resembling an angel, the bi-polar star-forming region called Sharpless 2-106, or S106, blazes brightly in this image from NASA’s Hubble. Super hot gas, glowing blue in the image, contrasts with the cooler red-colored gas and dust.
NASA, ESA, R. Ellis (Caltech), and the HUDF 2012 Team
Deep in this image – a tiny slice of sky taken with the Hubble – lie some of the most distant galaxies observed to date. The image shows the Hubble Ultra Deep Field 2012 and improves upon the previous Ultra Deep Field image.
Image credit: NASA/JPL-Caltech/Univ. of Wisconsin
NASA’s Spitzer Space Telescope has amassed a vast collection of infrared images. Spitzer can find beauty hidden in behind the densest dust clouds. This nebula is found in the constellation Scutum. I think it looks like a bumblebee.
Image credit: NASA/JPL-Caltech
The giant star Zeta Ophiuchi zips along so quickly that it creates a bow shock in the surrounding nebula. These gossamer ripples glow in infrared and can only be seen with Spitzer’s instruments.
Image credit: NASA/JPL-Caltech/Space Science Institute
NASA’s Cassini spacecraft continues to dazzle with this detailed close-up of the vortex at Saturn’s north pole in this image taken in November 2012.
Image credit: NASA/JPL-Caltech/Space Science Institute
Nearly as dazzling as the images, the skill of Cassini imaging team at finding unique shots is impressive. The bright moon Enceladus sits before the rings with the larger moon Titan glowing dimly in the distance. Cassini took this image in April 2012 from a distance of about 600,000 miles (1 million kilometers) from Enceladus.
Image credit: NASA/JPL-Caltech/Space Science Institute
Taken by Cassini at the beginning of 2012, Saturn’s moon Tethys lies before the wide shadows cast onto Saturn.
Image credit: NASA/JPL-Caltech/Space Science Institute
Sunlight scatters through the edge of Titan’s atmosphere in this image from Cassini. At the bottom of the moon’s limb, a hint of the high clouds that form the south polar vortex on Titan can be seen.
Image credit: NASA/JPL-Caltech/Space Science Institute
A tour of Saturn wouldn’t be complete without a beauty shot of the planet’s sweeping rings and complex cloud systems. Dwarfed by Saturn, Mimas sits near Saturn in this image from Cassini.
Image credit: NASA/Rebecca Roth
2012 is also known for some goodbyes. The three remaining shuttles were retired and sent to museums around the country. Space Shuttle Discovery, mounted atop a NASA 747 Shuttle Carrier flies near the US Capitol on April 17, 2012 enroute to its final home at the National Air & Space Museum’s Steven F. Udvar-Hazy Center.
NGC 3627 glows in the combined light of Hubble, Chandra, Spitzer and the Very Large Telescope in this image. Astronomers conducted a survey of 62 galaxies, including NGC 3627 to study monster black holes at their centers.
It’s not just pretty, it’s science. Like a starry watercolor, astronomers combining light from Earth and space-based observatories found 37 new supermassive black hole candidates lurking in nearby galaxies.
Included in that survey is NGC 3627 pictured above. Astronomers combined X-ray data from NASA’s Chandra X-ray Observatory, infrared data from the Spitzer Space Telescope, and optical data from the Hubble Space Telescope and the Very Large Telescope. The other images give the galaxy context but it’s the ghostly blue images from Chandra that show super bright in the X-ray images; X-ray light powered by material falling into a monster black hole.
Gas and dust slowly spins around the black hole creating a flattened disk, or accretion disk. As material falls inward, it heats up and releases large amounts of energy that shine brightly in the ultraviolet region of the spectrum.
NGC 3627, located about 30 million light-years from Earth, was just one of a survey of 62 nearby galaxies using archived data from Chandra and data from the Spitzer Infrared Nearby Galaxy Survey. Of those, 37 galaxies contained bright X-ray sources, indicating active black holes at their cores. Scientists believe that seven of those sources are new supermassive black hole candidates.
Combining ultraviolet and infrared observations confirm previous Chandra results that found that there may be many more galaxies powered by monster black holes than believed previously through optical surveys. Scientists say in the paper that low-levels of black hole activity previously may have been hidden by dust or washed out by the bright light of the galaxy.
Image caption: Bright X-ray sources glow a ghostly blue in this image in NGC 3627 from NASA’s Chandra X-ray Observatory. A study confirms previous Chandra results that indicate that more galaxies powered by monster black holes populate the cosmos.
This new image of the Hubble Ultra Deep Field (HUDF) 2012 campaign reveals a previously unseen population of seven faraway galaxies, which are observed as they appeared in a period 350 million to 600 million years after the Big Bang. Credit: NASA, ESA, R. Ellis (Caltech), and the UDF 2012 Team
Astronomers using NASA’s Hubble Space Telescope have spotted some of the most distant, dim and ancient galaxies ever detected in a new survey. The images, taken with Hubble’s Wide Field Camera 3 (WFC 3) looks further back in time than any previous Hubble observation, providing information about the conditions in the early Universe.
“This is like a scientific version of the story of Genesis,” said astronomer Avi Loeb from Harvard University.
The seven distant galaxies represent a previously unseen population of galaxies that formed more than 13 billion years ago, when the Universe was less than 3 percent of its present age. In these deepest images to date from Hubble, astronomers were able to take a sample of the amount of galaxies at the time. The results show a smooth decline in the number of galaxies with increasing look-back time to about 450 million years after the Big Bang.
The data provides the first reliable census of this uncharted period of cosmic history, according to the scientists. As astronomers look even deeper into the Universe, galaxy numbers appear to drop off smoothly leading them to believe that the “cosmic dawn” was gradual, not a dramatic event.
“Observations of the microwave afterglow from the Big Bang tell us that reionization happened more than about 13 billion years ago,” said Brant Robertson of the University of Arizona in Tucson, a member of the survey team. “Our data confirms that reionization was a drawn-out process occurring over several hundred million years with galaxies slowly building up their stars and chemical elements. There wasn’t a single dramatic moment when galaxies formed; it was a gradual process.”
These galaxies were found as part of an ambitious Hubble survey of an intensively studied patch of sky known as the Ultra Deep Field (UDF), which was originally taken in 2003-2004, focusing in on a small area in the sky in the constellation Fornax. In the new 2012 campaign, called UDF 2012, a team of astronomers led by Richard Ellis of the California Institute of Technology used the WFC3 to peer deeper into space in near-infrared light than any previous Hubble observation. The observations were made over a period of six weeks during August and September 2012, and the first scientific results are now appearing in a series of scientific papers. The UDF 2012 team is publicly releasing these unique data, after preparing them for other research groups to use.
“Hubble is achieving just great science,” said John Grunsfeld, former astronaut and NASA’s associate administrator for science, speaking at a briefing about the new survey. “This is an origins story, where we’re going back to the beginning, back to the first stars that appeared in the Universe. This validates that when we get James Webb Space Telescope online it will have a lot to look at and a lot to do.”
The James Webb Space Telescope is slated to launch in 2018.
Astronomers detected seven galaxies in the time period 400-600 million years after the Big Bang. All extremely distant, they ranged in distance with redshifts from 8.6 to nearly 12.
Astronomers study the distant universe in near-infrared light because the expansion of space stretches ultraviolet and visible light from galaxies into infrared wavelengths, a phenomenon called “redshift.” The more distant a galaxy, the higher its redshift.
Notably, one of the galaxies may be a distance record breaker, observed 380 million years after the birth of our universe in the Big Bang, corresponding to a redshift of 11.9. This is the galaxy UDFj-39546284, which was previously detected and was originally suggested as the most distant object ever found nearly two years ago by Hubble. Later observations put it at a redshift of 10.3, but the newly refined observations put it even more distant.
Scientists think that the universe began with the Big Bang about 13.7 billion years ago. Hydrogen formed about 400,000 years later but with no stars, spacetime was dark. About 200 million years later, hydrogen clouds collapsed forming the first stars and galaxies; what astronomers call the “cosmic dawn.” Light from these new stars began breaking down hydrogen into protons and electrons during a time period called cosmic reionization. In the present universe, scientists see galaxies growing in mass and size with the synthesis of elements, leading to the formation of complex molecules including the components to create life. Our Sun and solar system formed just over 4 billion years ago.
“The team pushed Hubble to its limits. This is probably the farthest back Hubble can look, according to the study leader, Richard Ellis. “We are pushing Hubble well beyond what it was designed to do.”
Bright pink nebulae encircle spiral galaxy NGC 922 in this image from the NASA/ESA Hubble Space Telescope. Credit: NASA/ESA. Zoom: John Williams/TerraZoom and Zoomify
Galaxies pack a wallop. A galactic bulls-eye ringed with pink nebulae is the only evidence of a rare galactic collision of NGC 922 that occurred millions of years ago. Clicking the button on the far right of the toolbar will allow awesomecosmicsauce to tantalize your eyes and work all of the pixels on your computer screen. Pressing the “ESC” will return you to the present universe.
Explore this awesome image from the NASA/ESA Hubble Space Telescope. While lovely, something is amiss in this image. NGC 922 used to be a spiral galaxy. As you zoom across the image, the spiral arms look distorted and disrupted. Hints of a galactic interaction are strewn across the galaxy from the large numbers of bright pink nebulae and blue stars to the spray of dim stars toward the top of the image. Ripples set up as the smaller galaxy passed through the gas and dust clouds of NGC 922 created new star formation. Ultraviolet radiation from these bright new stars cause hydrogen gas in the surrounding nebula to glow a characteristic pink. The tugs of gravity hurled thousands of stars outward.
Episode 60 of the Hubblecast explores NGC 922, a galaxy that has been hit square-on by another. Ripples of star-formation are still propagating out across thousands of light-years of space over 300 million years after the collision, making it a prime example of what astronomers call a collisional ring galaxy.
Scientists believe that millions of years ago a small galaxy, known as 2MASXI J0224301-244443, plunged through the heart of NGC 922. Sometimes, if a small galaxy hits a larger galaxy just right, a circle is formed. But more often than not, galaxies are not aligned perfectly. When a galaxy smacks another off center, one side of the ring is brighter than the other. NGC 922 is a prime example of what astronomers call collisional ring galaxies. Although only a few ring galaxies are seen in our cosmic neighborhood, of which the Cartwheel Galaxy is the most spectacular, ring galaxies appear to be commonplace as we peer further into the past.
As you explore the empty places of the image, look for faraway background galaxies. Several dim spiral galaxies dot the image both outside the galaxy and within the star-speckled interior.
NGC 922 is found about 330 million light-years from Earth toward the constellation Fornax. Sky mapper and French astronomer Nicolas Louis de Lacaille introduced Fornax, the Furnace, in 1756. Fornax is relatively devoid of stars allowing astronomers to peer deep into the universe. The constellation was the perfect target for the Hubble Ultra Deep Field image.
NASA/ESA Hubble Space Telescope image of NGC 922. Credit: NASA, ESA
This artist’s impression of Saturn’s moon Titan shows the change in observed atmospheric effects before, during and after equinox in 2009. The Titan globes also provide an impression of the detached haze layer that extends all around the moon (blue). This image was inspired by data from NASA’s Cassini mission. Image Credit: ESA
A certain slant, or shift, of light glinting off of Saturn’s moon Titan turns out to drive unexpected reversals in the moon’s atmosphere according to data from NASA’s Cassini spacecraft.
In a paper released in the November 28, 2012 issue of the journal Nature, scientists say in a press release that data from Cassini show evidence for sinking air where upwelling currents were seen earlier in the mission.
“Cassini’s up-close observations are likely the only ones we’ll have in our lifetime of a transition like this in action,” said Nick Teanby, the study’s lead author who is based at the University of Bristol, England, and is a Cassini team associate. “It’s extremely exciting to see such rapid changes on a body that usually changes so slowly and has a ‘year’ that is the equivalent of nearly 30 Earth years.”
Of the eight planets and dozens of moons in our solar system, just Earth, Venus, Mars and Titan have both a solid surface and a substantial atmosphere.
Cassini offers scientists a unique perspective during this change of seasons. The pole experiencing winter is typically pointed away from Earth because of its orbit around Saturn. Cassini provides scientists a platform to watch the atmosphere change over time and study the moon from angles impossible from Earth. It arrived at the ringed planet in 2004. Models of Titan’s atmosphere have predicted changes for two decades but Cassini is just now seeing new circulation patterns arise.
“Understanding Titan’s atmosphere gives us clues for understanding our own complex atmosphere,” said Scott Edgington, Cassini deputy project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “Some of the complexity in both places arises from the interplay of atmospheric circulation and chemistry.”
While scientists recently have watched the formation of haze and a vortex over Titan’s south pole, other Cassini instruments, such as the composite infrared spectrometer (CIRS), have gathered data tied more to the circulation and chemistry of Titan’s orangish atmosphere especially at higher altitudes. The CIRS instrument also reveals subtle changes in vertical winds and global circulation. The instrument shows that atmospheric circulation extends about 100 km, or 60 miles, higher than expected. This is important in explaining the orangish tint to Titan’s atmosphere. A haze layer, first detected by Voyager 1, may be a region rich in small haze particles that combine to form larger aggregates that descend deep into the atmosphere giving the moon its characteristic color.
Scientists have narrowed down the atmospheric reversal to about six months near the August 2009 equinox when the Sun was shining directly on Titan’s equator.
“Next, we would expect to see the vortex over the south pole build up,” said Mike Flasar, the CIRS principal investigator at NASA’s Goddard Space Flight Center in Greenbelt, Md. “As that happens, one question is whether the south winter pole will be the identical twin of the north winter pole, or will it have a distinct personality? The most important thing is to be able to keep watching as these changes happen.”
Second image caption: This true color image captured by NASA’S Cassini spacecraft before a distant flyby of Saturn’s moon Titan on June 27, 2012, shows a south polar vortex, or a swirling mass of gas around the pole in the atmosphere. Image Credit: NASA/JPL-Caltech/Space Science Institute
An anaglyph of the moving topography of Nili Patera on Mars. Credit: NASA/JPL/University of Arizona
Get your 3-D glasses (the red-and-green kind) ready, we’re going on a trip to Mars.
Let your gaze drift across this anaglyph of the dunes of Nili Patera taken from NASA’s HiRISE camera aboard Mars Reconnaissance Orbiter. HiRISE images many targets twice, within seconds of each other, so scientists can see a location from different angles. The images are used to make more accurate maps. Only problem is, dunes move, making the job of a Mars mapper a little difficult.
Besides making a beautiful, but sometimes eye-bending, picture, the images are also used to make digital elevation models or DEMs. These DEMs can be precise within centimeters. If the pair of images are taken in an area that doesn’t change much, scientists can get a good elevation model. Scientists also get lucky when images are taken in quick succession as in the case of Nili Patera, a huge caldera near the Martian equator within the dark Syrtis Major Planum.
The dunes in this field of sand are active. By comparing the height of the moving dunes using the DEM, scientists find that these dunes are similar to Antarctic dunes which are driven by strong, sustained winds. One of the most surprising finds, according to the HiRISE website, is the notion that the dunes remain stable. Their entire volumes are made up of mobile sand. Similar to Earth, winds on Mars are capable of moving large amounts of sand meaning not only does wind drive dune migration but also landscaping such as sand blasting.
A close-up color version of one of the dunes in Nili Patera. Credit: NASA/JPL/University of Arizona