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Origin of Enceladus’ 101 Geysers Revealed

Jets of liquid water can be seen shooting out of Enceladus' icy surface. They are seen "spewing 200kg of water vapour and ice particles into space each second – enough to fill an Olympic swimming pool every few hours" (Cosmos) Credit: NASA/JPL

Jets of liquid water can be seen “spewing 200kg of water vapour and ice particles into space each second – enough to fill an Olympic swimming pool every few hours” (Cosmos). Image Credit: NASA/JPL

Using data provided by the Cassini-Huygens spacecraft scientists have pinpointed 101 geysers on Enceladus, one of Saturn’s icy moons. Issued in a press release by NASA, July 28th, 2014, the findings are helping scientists understand the geological processes that may allow for liquid water to exist on the moon’s surface.

The first geysers were spotted nearly ten years ago on the moon. Since then scientists have been able to resolve not only where they were being formed, but also how. Early hypothesis’ suggested that pressure built up by the flexing of the small moon’s surface was heating ice into vapor; once an enough tidal friction melted an opening on the surface, a geyser would erupt allowing the pressure to be released.

Using Cassini scientists were able to triangulate the locations of 101 fountains and have found the south pole of the moon to be a breeding ground for the geysers. Tiger stripe fractures run across the terrain of Enceladus in this area. Measurements taken over the last seven years have indicated that the geysers are erupting from hot spots along these striped fractures. This is a great clue for the scientists because it offers a possible origin for the water that spews from these vents.

Scientists have been able to correlate the intensity of the jets to thermal radiation as well as tidal stressors. It was apparent that higher temperatures were associated with the vents, however, it was unknown if increased temperatures were causing the geysers or vice versa. By analyzing high-resolution data gathered by Cassini’s heat-sensing technology in 2010 and 2012, the scientists could say definitively which came first, the chicken or the egg. In this case, it is the geysers that are causing the increased temperatures on the surface of Enceladus. Carolyn Porco, leader of the Cassini image team said in a report published in the Astronomical Journal, “[The results] told us the geysers are not a near-surface phenomenon, but have much deeper roots.”

Image Credit: NASA/JPL-Caltech/Space Science Institute

Image Credit: NASA/JPL-Caltech/Space Science Institute

Scientists now believe that the underground sea that resides on the moon is the most plausible source of these watery fountains. “They also found that narrow pathways through the ice shell can remain open from the sea all the way to the surface, if filled with liquid water.” Enceladus’ sea is believed to be nearly 10 kilometers deep, covered by 30-40 kilometers of ice near its south pole. It is still unclear why much of the moon’s water appears to be concentrated in this region. Porco had long suspected that Enceladus was releasing heat from within. Small silica particles have been spotted in the plumes, this combined with the newest evidence of deep channels connecting the moon’s surface with its underground sea gives scientists more hope of possibly finding life here.

In an article published in the journal Nature, in April, 2014, it states, “At the bottom of the Enceladus ocean, the water presumably comes in contact with the moon’s rocky core. “What matters about the new result is they say they have evidence for the ocean contacting rock,” says Christopher McKay, an astrobiologist at NASA’s Ames Research Center in Moffett Field, California. “That’s very important because pure water is not interesting biologically — the water needs to interact with rock in order to put in the stuff that’s useful for life.”

Hydrothermal vents on Earth act as transmitters of heat and chemicals from within the planet’s interior and they have been found to harbor the most extreme forms of life. Only further research will tell if similar underwater outlets are heating Enceladus, and whether or not biological life may be hiding there.

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Origins of Mars’ Mysterious Gullies Solved

These two images, taken four years apart, show the martian gully evolving over time. (Credit: NASA/JPL/Malin Space Science Systems)

These two images, taken four years apart, show the martian gully evolving over time. (Credit: NASA/JPL/Malin Space Science Systems)

It was nearly 15 years ago when scientists first spotted gullies on Mars. Since then they’ve had the opportunity to make continual observations of these structures using the Mars Reconnaissance orbiter’s high tech equipment. The initial findings led to many questions; primarily, could these gullies be formed by flows of liquid water?

If that were the case, the implications would be truly sensational. Thus far, we have only detected frozen waterwater vapor and a few characteristics that indicate Mars was once a wet world. Discovering liquid water could be game changer for many reasons, but above all, it would put Mars as the solid front runner in the search for  life in the solar system. Needless to say,  a lot of people have their fingers crossed.

UNLOCKING THE CLUES

To figure out whether or not it was water sculpting the gullies, scientists turned to MRO once again. On board the spacecraft resides the High Resolution Imaging Science Experiment camera, otherwise known as HiRISE. The camera has played an important role in distinguishing significant features of Mars’ terrain in resoundingly high definition.

Serina Diniega of NASA’s Jet Propulsion Laboratory says, “This [technology] allows us to make repeated observation[s] and to examine surface changes over time”. She goes on to include, “Much of the information we have about gully formation, and other active processes, come from the longevity of MRO and other orbiters”(NASA).

Since arriving on the red planet, HiRISE has focused its attention on 356 sites that contain gullies, which on Earth, are trenches carved by the movement of water down a slope. Astoundingly, thirty-eight of the sites indicate change over time. This was a surprising discovery, given that earlier theories had proposed that the odd streaks on Mars’ surface formed thousands of years ago while it was still a vibrant world. In actuality, they observed the gullies transforming, sometimes dramatically, before their eyes. Some showed evidence of additional debris build up at the base of the trenches, others spawned new branches. It was now clear that gullies are still quite active on Mars.

Side-by-side comparisons of photos taken of the same location helped researchers verify when the gully seemed to be flowing most prominently. As it turned out, the activity “coincided with seasonal carbon dioxide frost and temperatures that would not have allowed for liquid water” stated NASA’s press release (announced on July 10th, 2014).

This set of images was taken by HiRISE in 2010 and 2013. A new channel is shown forming on the martian slope. (Credit: NASA/JPL-Caltech/Univ. of Arizona)

This set of images was taken by HiRISE in 2010 and 2013. A new channel is shown forming on the martian slope. Click to enlarge. (Credit: NASA/JPL-Caltech/Univ. of Arizona)

THE TRUE ORIGINS

So, if it isn’t liquid water, what’s creating martian trenches? The next obvious contender is frozen carbon dioxide, otherwise knows as dry ice (it comprises approximately 95% of Mars’ atmosphere). We know that carbon dioxide (Co2) freezes at -78.5 ºC (-109.3 ºF) at sea level (one atmospheric pressure); therefore, dry ice is not found naturally on Earth, our surface temperature and atmospheric pressure just aren’t conducive to the freezing of Co2. Conversely, on Mars, the temperatures can drop down to -153 °C (-225 ºF) at the poles during winter. In comparison, during the summer, temperatures at the equator can warm up to 20 °C (70 °F).

Scientists now believe the trenches have been carved into Mars’ surface by seasonal dry ice formations. The sublimation, or phase transfer, of carbon dioxide gas into a solid could create enough lubrication to help move along the flow of the frozen material. As the atmosphere freezes more gas, its mass becomes greater, thus gravity might also aid downward flow.

While this research — recently published online in the journal ICARUS — suggests that liquid water isn’t the catalyst, dry ice is still a pretty exciting consolation. Lead author Colin Dundas (from the U.S. Geological Survey’s Astrogeology Science Center) remains optimistic, saying, “I like that Mars can still surprise us…Martian gullies are fascinating features that allow us to investigate a process we just don’t see on Earth”.


 


This article was originally published by FQTQ, July 15, 2014. 

Cleaning the Cosmos with Space Harpoons

Infograph by NASA's Jet Propulsion Laboratory

Infograph by NASA’s Jet Propulsion Laboratory

 

There are over 17,000 individual pieces of human-made space debris, floating without regard, in Earth’s low orbit. These are the discarded remnants of nearly sixty years of space exploration. Space junk consists of anything from spent fuel cells to battery packs. The nearly twenty thousand pieces of trash left in space accounts for items that are large enough to be tracked and cataloged, objects roughly the size of a coffee cup. If scientists account for even smaller debris, bits and pieces 1 cm or larger: flecks of paint, nuts, bolts, screws, etcetera, and the number is expected to exceed 300,000 (NASA).

Image Credit: ESA

Image Credit: ESA

It’s becoming apparent that humans are no better at keeping debris out of space, than we are at keeping rubbish out of the oceans. The difference is trash in the oceans contributes to global pollution, disturbances in ecosystems, and the destruction of species unable to adapt our insatiable thirst for development and technology. The junk we have accumulated in space, on the other hand, has the potential to anchor us to this ever-polluted Earth indefinitely; creating an exponentially growing shield of debris that could make future space travel obsolete.

In addition to possibly halting our route to the universe, space garbage posses danger to any number of beneficial satellites that also inhabit low Earth orbit. Without such machines, much of the technologies we have grown accustom to today would cease to function. We use satellites for tracking weather and making predictions, navigation while driving, for communication, and scientific research. The potential for collisions between space debris and any one of these satellites is a viable concern.

Harpooning System. Image Source: ESA

Harpooning System. Image Source: ESA

SPACE HARPOONS — SPEARING THE BEASTS:

This why the European Space Agency has announced they hope to start the cosmic clean up as soon as 2021. The e.DeOrbit mission is part of the ESA’s Clean Space Initiative; it’s main task: to hunt down renegade space debris in key orbiting regions and safely remove it. A variety of suggestions have been made for how to capture the wreckage. Nets and mechanical arms have been popular choices, and may very well aid in tidying up space; however, recent ESA research has shown promising results using harpoon technology.

Preliminary investigations, by Airbus Defense and Space, regarding harpoon technology and other waste removal concepts have already taken place. Paying homage to an ancient hunting technique, scientists hope to shoot out a harpoon attached to a tether, pierce the debris and reel it back in.

A prototype harpoon was projected into representative satellite material to assess its penetration, its strength as the target is pulled close and the generation of additional fragments that might threaten the e.DeOrbit satellite.

Scientists have already assessed a mock-up version of the technology. It was shot into demonstrative space junk to test how well it can puncture the material, whether it was powerful enough to reel it back in, and most importantly, that it doesn’t create more fragments in its wake.

 “As a next step, ESA plans to build and test a prototype ‘breadboard’ version in the hope of adopting the harpoon and its ejection mechanism for the mission.The project will investigate all three stages of harpooning through computer models, analysis and experiments, leading to a full hardware demonstration.”

[Reference: ESA]

It is yet to be seen which means of trash removal will be the most beneficial. It may prove necessary for us to employ a variety of methods dependent on the size of the material in question.

Check out From Quarks to Quasars for more awesome space articles!

NASA Plans to Capture Asteroid In Moon’s Orbit

Photo credit: NASA/AMA

Photo credit: NASA/AMA

As part of the Asteroid Redirect Mission (ARM), NASA and cooperative scientists have been searching for a suitable asteroid to capture and redirect into the moon’s orbit for continual research. The ARM spacecraft is proposed to launch in 2019. Once set in orbit, the hands-on examination of the asteroid will begin in the 2020s. The mission has two main focuses: to develop the expertise needed for deep space travel to Mars and beyond, as well as providing an opportunity to test technologies that will keep Earth safe from any possible future asteroid impacts.

There are two concepts set for NASA’s ARM operation: “The first is to fully capture a very small asteroid in open space, and the second is to collect a boulder-sized sample off of a much larger asteroid. Both concepts would require redirecting an asteroid less than 32 feet (10 meters) in size into the moon’s orbit. The agency will choose between these two concepts in late 2014 and further refine the mission’s design.”

Recently a $4.9 million award has been offered for concept studies that will lead to the ARM’s success. Starting in July, a six-month research period will begin that addresses the issues of the mission. During this time the technologies, mechanics and resources needed for the mission will be perfected.

As of now, only nine asteroids have been identified that meet the criteria for possible mission nominees. Using NASA’s Spitzer Space Telescope, the most recent asteroid candidate has been identified. The telescope’s “warm” mission began in 2009 once its coolant ran out as planned, and since then Spitzer has been used for more long term and targeted observations. In particular this makes asteroid observation easier as infrared detection is the best way to study less luminous objects.

The recognition of the latest contending asteroid, named 2011 MD, for possible capture as part of the Asteroid Redirect Mission, was published June 19th, 2014 in the Astrophysical Journal Letters. Lead author of the study, Michael Mommert of Northern Arizona University says, “From its perch up in space, Spitzer can use its heat-sensitive infrared vision to spy asteroids and get better estimates of their sizes.” To be deemed valid, the asteroid must be both the right size and mass, but also the rotation rate must be considered to make its capture feasible.

2011 MD is one of the lucky asteroids that has met all necessary criteria for redirection. It has a diameter of about three to six meters (10-20 feet) with a density similar to water, this suggests that the asteroid is mostly empty space, as solid rock is usually at least three times denser than water. 2011 MD may either be a singular solid rock with a halo of particles surrounding it or a collection of smaller space rocks held in tandem by gravity. Only further observation will conclude indefinitely what its composition is.

The idea of capturing an asteroid and setting it in orbit around the moon is truly exciting! It will be the first time that humans have achieved such a massive cosmic endeavor. Building a stellar environment that fits our research needs almost seems more science fiction that reality; however, if we wish to take humans into deep space it is a necessary leap to make. Not only is the Asteroid Redirect Mission awesome in its concept, it will prove to be incredibly valuable in a scientific standpoint as well. John Grunsfeld, associate administrator for NASA’s Science Mission Directorate, says, “Observing these elusive remnants that may date from the formation of our solar system as they come close to Earth, is expanding our understanding of our world and the space it resides in.”

Sources:

NASA, Spitzer Spies an Odd, Tiny Asteroid

NASA, NASA Announces Latest Progress, Upcoming Milestones in Hunt for Asteroids

This article was originally written for and published by From Quarks to Quasars.

Giving Birth to the Serpent’s Stars

Serpens Nebula in infrared. Some of the youngest stars in the Milky Way are seen in yellow and red, in this recent image taken by NASA’s Spitzer Space Telescope. Image credit: NASA/JPL-Caltech/2MASS

Serpens Nebula in infrared. Some of the youngest stars in the Milky Way are seen in yellow and red, in this recent image taken by NASA’s Spitzer Space Telescope. Image credit: NASA/JPL-Caltech/2MASS

Revealed in this recent image taken by NASA’s Spitzer Space Telescope and the Two Micron All Sky Survey (2MASS) is the star-forming region called the Serpens Cloud Core. The cluster shown contains stars that are among the youngest found in our galaxy! Using infrared technology the telescopes captured details from within the stellar breeding ground that were previously unavailable.

By assigning visible colors to the infrared light within the structure, astronomers are able to peer through the fog of gas and dust to observe emerging stars taking shape. “They appear as red, orange and yellow points clustered near the center of the image. Other red features include jets of material ejected from these young stars” (NASA). The nebula’s central cloud, which is chock-full of star birthing ingredients, is colored blue.

Located 750 light-years away in the Serpens (Serpent’s) constellation, this region of space is lacking the existence of super luminous stars. “The core contains a dense, very young, low mass stellar cluster with more than 300 objects in all evolutionary phases, from collapsing gaseous condensations to pre-main sequence stars” (The Serpens Molecular Cloud). Stars, located in the foreground and background of the Serpent, provide most of the pinpricks of light seen in the picture. The formation itself consists of low to moderately sized stars, which appear dimmer in the night sky.

It took an over 16 hours of observation and a compilation of 82 individual photographs to construct the image above. Although the use of light filters makes it possible to examine portions of space that would normally be invisible to us, there is still a region within the Serpens Cloud Core, located to the left, which is too thick for even the infrared filter to penetrate.

By continuing to study such stellar nurseries in detail, scientists can begin to unravel the mystery of how stars with varying masses form within nebulae. It also allows us to understand in, further detail, how chemical composition contributes to the fusion process of star’s lifetime. The evolutionary actions that occur with nebulae contain a wealth of information that can then be applied to future examinations of the cosmos.

 

Written for From Quarks to Quasars, June 12, 2014. For more science news articles check them out!