Posted on by Nancy Atkinson

Pure Metal Asteroid Has Mysterious Water Deposits

An artist’s concept of the Psyche spacecraft, a proposed mission for NASA’s Discovery program that would explore the huge metal Psyche asteroid from orbit. Credit: NASA/JPL-Caltech.

Water has been showing up in all sorts of unexpected places in our Solar System, such as the Moon, Mercury and Jupiter’s moon Ganymede. Add one more place to the list: Asteroid 16 Psyche. This metal-rich asteroid may have traces of water molecules on its surface that shouldn’t be there, researchers say.

Psyche is thought to be the largest metallic asteroid in the Solar System, at 300 km (186 miles) across and likely consists of almost pure nickel-iron metal. Scientists had thought Psyche was made up of the leftover core of a protoplanet that was mostly destroyed by impacts billions of years ago, but they may now be rethinking that.

“The detection of a 3 micron hydration absorption band on Psyche suggests that this asteroid may not be metallic core, or it could be a metallic core that has been impacted by carbonaceous material over the past 4.5 Gyr,” the team said in their paper.

While previous observations of Psyche had shown no evidence for water on its surface, new observations with the NASA Infrared Telescope Facility found evidence for volatiles such as water or hydroxyl on the asteroid’s surface. Hydroxyl is a free radical consisting of one hydrogen atom bound to one oxygen atom.

“We did not expect a metallic asteroid like Psyche to be covered by water and/or hydroxyl,” said Vishnu Reddy, from the University of Arizona’s Lunar and Planetary Laboratory, a co-author of the new paper about Psyche. “Metal-rich asteroids like Psyche are thought to have formed under dry conditions without the presence of water or hydroxyl, so we were puzzled by our observations at first.”

Asteroids usually fall into two categories: those rich in silicates, and those rich in carbon and volatiles. Metallic asteroids like Psyche are extremely rare, making it a laboratory to study how planets formed.

he asteroid Psyche is one of the larger asteroids. Credit: Lindy T. Elkins-Tanton
he asteroid Psyche is one of the larger asteroids. Credit: Lindy T. Elkins-Tanton

For now, the source of the water on Psyche remains a mystery. But Redddy and his colleagues propose a few different explanations. One is, again, Psyche may not be as metallic as previously thought. Another option is that the water or hydroxyl could be the product of solar wind interacting with silicate minerals on Psyche’s surface, such as what is occurring on the Moon.

The most likely explanation, however is that the water seen on Psyche might have been delivered by carbonaceous asteroids that impacted Psyche in the distant past, as is thought to have occurred on early Earth.

“Our discovery of carbon and water on an asteroid that isn’t supposed to have those compounds supports the notion that these building blocks of life could have been delivered to our Earth early in the history of our solar system,” said Reddy.

If we’re lucky, we won’t have to wait too long to find out more about Psyche. A mission to Psyche is on the short list of mission proposals being considered by NASA, with a potential launch as early as 2020. Reddy and team said an orbiting spacecraft could explore this unique asteroid and determine if whether there is water or hydroxyl on the surface.

Sources: Europlanet, University of Arizona, paper: Detection of Water and/or Hydroxyl on Asteroid (16) Psyche.

Posted on by Bob King

Phenomenal New View of Ceres ‘Lonely Mountain’ Reveals Signs of Volcanic Activity

Ahuna Mons towers over the Cerean landscape in this photo taken by the Dawn spacecraft. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI
A lonely 3-mile-high (5-kilometer-high) mountain on Ceres is likely volcanic in origin, and the dwarf planet may have a weak, temporary atmosphere. These are just two of many new insights about Ceres from NASA's Dawn mission published this week in six papers in the journal Science. "Dawn has revealed that Ceres is a diverse world that clearly had geological activity in its recent past," said Chris Russell, principal investigator of the Dawn mission, based at the University of California, Los Angeles. A Temporary Atmosphere A surprising finding emerged in the paper led by Russell: Dawn may have detected a weak, temporary atmosphere. Dawn's gamma ray and neutron (GRaND) detector observed evidence that Ceres had accelerated electrons from the solar wind to very high energies over a period of about six days. In theory, the interaction between the solar wind's energetic particles and atmospheric molecules could explain the GRaND observations. A temporary atmosphere would be consistent with the water vapor the Herschel Space Observatory detected at Ceres in 2012-2013. The electrons that GRaND detected could have been produced by the solar wind hitting the water molecules that Herschel observed, but scientists are also looking into alternative explanations. "We're very excited to follow up on this and the other discoveries about this fascinating world," Russell said. Ahuna Mons as a Cryovolcano Ahuna Mons is a volcanic dome unlike any seen elsewhere in the solar system, according to a new analysis led by Ottaviano Ruesch of NASA's Goddard Space Flight Center, Greenbelt, Maryland, and the Universities Space Research Association. Ruesch and colleagues studied formation models of volcanic domes, 3-D terrain maps and images from Dawn, as well as analogous geological features elsewhere in our solar system. This led to the conclusion that the lonely mountain is likely volcanic in nature. Specifically, it would be a cryovolcano -- a volcano that erupts a liquid made of volatiles such as water, instead of silicates. "This is the only known example of a cryovolcano that potentially formed from a salty mud mix, and that formed in the geologically recent past," Ruesch said. For more details on this study, see: http://www.nasa.gov/feature/goddard/2016/ceres-cryo-volcano Ceres: Between a Rocky and Icy Place While Ahuna Mons may have erupted liquid water in the past, Dawn has detected water in the present, as described in a study led by Jean-Philippe Combe of the Bear Fight Institute, Winthrop, Washington. Combe and colleagues used Dawn's visible and infrared mapping spectrometer (VIR) to detect probable water ice at Oxo Crater, a small, bright, sloped depression at mid-latitudes on Ceres. Exposed water-ice is rare on Ceres, but the low density of Ceres, the impact-generated flows and the very existence of Ahuna Mons suggest that Ceres' crust does contain a significant component of water-ice. This is consistent with a study of Ceres' diverse geological features led by Harald Hiesinger of the Westfälische Wilhelms-Universität, Münster, Germany. The diversity of geological features on Ceres is further explored in a study led by Debra Buczkowski of the Johns Hopkins Applied Physics Laboratory, Laurel, Maryland. Impact craters are clearly the most abundant geological feature on Ceres, and their different shapes help tell the intricate story of Ceres' past. Craters that are roughly polygonal -- that is, shapes bounded by straight lines -- hint that Ceres' crust is heavily fractured. In addition, several Cerean craters have patterns of visible fractures on their floors. Some, like tiny Oxo, have terraces, while others, such as the large Urvara Crater (106 miles, 170 kilometers wide), have central peaks. There are craters with flow-like features, and craters that imprint on other craters, as well as chains of small craters. Bright areas are peppered across Ceres, with the most reflective ones in Occator Crater. Some crater shapes could indicate water-ice in the subsurface. The dwarf planet's various crater forms are consistent with an outer shell for Ceres that is not purely ice or rock, but rather a mixture of both -- a conclusion reflected in other analyses. Scientists also calculated the ratio of various craters' depths to diameters, and found that some amount of crater relaxation must have occurred. Additionally, there are more craters in the northern hemisphere of Ceres than the south, where the large Urvara and Yalode craters are the dominant features. "The uneven distribution of craters indicates that the crust is not uniform, and that Ceres has gone through a complex geological evolution," Hiesinger said. Distribution of Surface Materials What are the rocky materials in Ceres' crust? A study led by Eleonora Ammannito of the University of California, Los Angeles, finds that clay-forming minerals called phyllosilicates are all over Ceres. These phyllosilicates are rich in magnesium and also have some ammonium embedded in their crystalline structure. Their distribution throughout the dwarf planet's crust indicates Ceres' surface material has been altered by a global process involving water. Although Ceres' phyllosilicates are uniform in their composition, there are marked differences in how abundant these materials are on the surface. For example, phyllosilicates are especially prevalent in the region around the smooth, "pancake"-like crater Kerwan (174 miles, 280 kilometers in diameter), and less so at Yalode Crater (162 miles, 260 kilometers in diameter), which has areas of both smooth and rugged terrain around it. Since Kerwan and Yalode are similar in size, this may mean that the composition of the material into which they impacted may be different. Craters Dantu and Haulani both formed recently in geologic time, but also seem to differ in composition. "In comparing craters such as Dantu and Haulani, we find that their different material mixtures could extend beneath the surface for miles, or even tens of miles in the case of the larger Dantu," Ammannito said. Looking Higher Now in its extended mission, the Dawn spacecraft has delivered a wealth of images and other data from its current perch at 240 miles (385 kilometers) above Ceres' surface, which is closer to the dwarf planet than the International Space Station is to Earth. The spacecraft will be increasing its altitude at Ceres on Sept. 2, as scientists consider questions that can be examined from higher up. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI
Whoa – what a sight! Ceres’ lonely mountain, Ahuna Mons, is seen in this simulated perspective view. The elevation has been exaggerated by a factor of two. The view was made using enhanced-color images from NASA’s Dawn mission in August from an altitude of 240 miles (385 km) in August 2016. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI

An isolated 3-mile-high (5 km) mountain Ahuna Mons on Ceres is likely volcanic in origin, and the dwarf planet may have a weak, temporary atmosphere. These are just two of many new insights about Ceres from NASA’s Dawn mission published this week in six papers in the journal Science.

Ceres' mysterious mountain Ahuna Mons is seen in this mosaic of images from NASA's Dawn spacecraft. On its steepest side, this mountain is about 3 miles (5 kilometers) high. Its average overall height is 2.5 miles (4 kilometers). The diameter of the mountain is about 12 miles (20 kilometers). Dawn took these images from its low-altitude mapping orbit, 240 miles (385 kilometers) above the surface, in December 2015. Credits: NASA/JPL/Dawn mission
Ahuna Mons is seen in this mosaic of images from NASA’s Dawn spacecraft. On its steepest side, this mountain is about 3 miles (5 km) high. Its average overall height is 2.5 miles (4 km). The diameter of the mountain is about 12 miles (20 km). Dawn took these images from its low-altitude mapping orbit, 240 miles (385 kilometers) above the surface, in December 2015.
Credits: NASA/JPL/Dawn mission

“Dawn has revealed that Ceres is a diverse world that clearly had geological activity in its recent past,” said Chris Russell, principal investigator of the Dawn mission, based at the University of California, Los Angeles.

The Ahuna Mons dome compared to a dome in Russia. The similarity in appearance is striking though the difference in size is large. Credit: NASA
The Ahuna Mons dome compared to a dome in Russia. The similarity in appearance is striking though the difference in size is large. Credit: NASA

Ahuna Mons is a volcanic dome similar to earthly and lunar volcanic domes but unique in the solar system, according to a new analysis led by Ottaviano Ruesch of NASA’s Goddard Space Flight Center and the Universities Space Research Association. While those on Earth erupt with molten rock, Ceres’ grandest peak likely formed as a salty-mud volcano. Instead of molten rock, salty-mud volcanoes, or “cryovolcanoes,” release frigid, salty water sometimes mixed with mud.


Learn more about Ahuna Mons

“This is the only known example of a cryovolcano that potentially formed from a salty mud mix, and that formed in the geologically recent past,” Ruesch said. Estimates place the mountain formation within the past billion years.

Dawn may also have detected a weak, temporary atmosphere; the probe’s gamma ray and neutron (GRaND) detector observed evidence that Ceres had accelerated electrons from the solar wind to very high energies over a period of about six days. In theory, the interaction between the solar wind’s energetic particles and atmospheric molecules could explain the GRaND observations.

Dwarf planet Ceres is located in the asteroid belt, between the orbits of Mars and Jupiter. Observations by ESA’s Herschel space observatory between 2011 and 2013 find that the dwarf planet has a thin water-vapour atmosphere. It is the first unambiguous detection of water vapour around an object in the asteroid belt. The inset shows the water absorption signal detected by Herschel on 11 October 2012. Copyright ESA/ATG medialab/Küppers et al.
Dwarf planet Ceres is located in the asteroid belt, between the orbits of Mars and Jupiter. Observations by ESA’s Herschel Space Observatory between 2011 and 2013 found that the dwarf planet has a thin water-vapor atmosphere, the first detection ever of water vapor around an asteroid in the asteroid belt. Copyright ESA/ATG medialab/Küppers et al.

A temporary atmosphere would confirm the water vapor the Herschel Space Observatory detected at Ceres in 2012-2013. The electrons that GRaND detected could have been produced by the solar wind hitting the water molecules that Herschel observed, but scientists are also looking into alternative explanations.

While Ahuna Mons may have erupted liquid water in the not-too-distant past, Dawn found probable water ice right now in the mid-latitude Oxo Crater using its visible and infrared mapping spectrometer (VIR).

The small, bright crater Oxo (6 miles, 10 kilometers wide) on Ceres is seen in this perspective view. The elevation has been exaggerated by a factor of two. The view was made using enhanced-color images from NASA's Dawn mission. Dawn's visible and infrared mapping spectrometer (VIR) has found evidence of water ice at this crater. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
The small, bright crater Oxo (6 miles / 10 km wide) on Ceres is seen in this perspective view. The elevation has been exaggerated by a factor of two. The view was made using enhanced-color images from NASA’s Dawn mission. Dawn’s visible and infrared mapping spectrometer (VIR) has found evidence of water ice at this crater. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Exposed water-ice is rare on the dwarf planet, but the low density of Ceres — 2.08 grams/cm3 vs. 5.5 for Earth — the impact-generated ice detection and the the existence of Ahuna Mons suggest that Ceres’ crust does contain a significant amount of water ice.

Impact craters are clearly the most abundant geological feature on Ceres, and their different shapes help tell the complex story of Ceres’ past. Craters that are roughly polygonal — shapes bounded by straight lines — hint that Ceres’ crust is heavily fractured. In addition, several Cerean craters display fractures on their floors. There are craters with flow-like features. Bright areas are peppered across Ceres, with the most reflective ones in Occator Crater. Some crater shapes could indicate water-ice in the subsurface.

In this illustration, a mud slurry rises up through Ceres' crust to build a dome such as Ahuna Mons. Credit: Goddard Media Studios
In this illustration, a mud slurry rises up through Ceres’ crust to build a dome like Ahuna Mons. Click to see the animation. Credit: Goddard Media Studios

All these crater forms imply an outer shell for Ceres that is not purely ice or rock, but rather a mixture of both. Scientists also calculated the ratio of various craters’ depths to diameters, and found that some amount of crater relaxation must have occurred as icy walls gradually slump.

“The uneven distribution of craters indicates that the crust is not uniform, and that Ceres has gone through a complex geological evolution,” Hiesinger said.

The rim of Hamori Crater on Ceres is seen in the upper right portion of this image, which was taken by NASA's Dawn spacecraft. Hamori is located in the southern hemisphere of Ceres and measures 37 miles (60 kilometers) wide. Researchers named Hamori for a Japanese god said to protect the leaves of trees.
The rim of Hamori Crater on Ceres is seen in the upper left portion of this image, which was taken by NASA’s Dawn spacecraft. Clay is found at many locations on the dwarf planet. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Ceres’ crust also appears loaded with clay-forming minerals called phyllosilicates. These phyllosilicates are rich in magnesium and also have some ammonium embedded in their crystalline structure. Their distribution throughout the dwarf planet’s crust indicates Ceres’ surface material has been altered by a global process involving water.

Now in its extended mission, the Dawn spacecraft has been increasing its altitude since Sept. 2 as scientists stand back once again for a broader look at Ceres under different lighting conditions now compared to earlier in the mission.

Posted on by Nancy Atkinson

First Detection of Water Clouds Outside Our Solar System

Artist's conception of how WISE 0855 might appear if viewed close-up in infrared light. Artwork by Joy Pollard, Gemini Observatory/AURA.

Brown dwarfs – those not-quite-a-planet and not-quite-a-star objects – are intriguing oddities that are too low in mass to burn hydrogen, but are more massive than planets. They only emit a faint amount of light, so they are hard to detect, making scientists unsure of how many of them might be out there in our galaxy.

But astronomers have been keeping an eye one particular brown dwarf known called WISE 0855. Just 7.2 light-years from Earth, it is the coldest known object outside of our Solar System and is just barely visible at infrared wavelengths. But with some crafty spectroscopic observing techniques, astronomers have now determined this object has some exciting characteristics: its atmosphere is full of clouds of water vapor. This is the first time water clouds have been detected outside of our Solar System.

“It’s five times fainter than any other object detected with ground-based spectroscopy at this wavelength,” said Andrew Skemer, assistant professor of astronomy and astrophysics at UC Santa Cruz and the first author on a paper on WISE 0855 published in Astrophysical Journal Letters (paper is available on arXiv here). “Now that we have a spectrum, we can really start thinking about what’s going on in this object. Our spectrum shows that WISE 0855 is dominated by water vapor and clouds, with an overall appearance that is strikingly similar to Jupiter.”

This brown dwarf’s full name is WISE J085510.83-071442.5, but we’re among friends, so it’s W0855 for short. It has about five times the mass of Jupiter and is the coldest brown dwarf ever detected, with an average temperature of about 250 degrees Kelvin, or minus 10 degrees F, minus 20 C. That makes it nearly as cold as Jupiter, which is 130 degrees Kelvin.

“WISE 0855 is our first opportunity to study an extrasolar planetary-mass object that is nearly as cold as our own gas giants,” Skemer said.

Skemer and his team used the Gemini-North telescope in Hawaii and the Gemini Near Infrared Spectrograph to observe WISE 0855 over 13 nights for a total of about 14 hours. Skemer was part of a team that studied this object in 2014 found tentative indications of water clouds based on very limited photometric data. Skemer said obtaining a spectrum (which separates the light from an object into its component wavelengths) was the only way to detect this object’s molecular composition.

A video about the 2014 discovery and study of WISE 0855:

WISE 0855 is too faint for conventional spectroscopy at optical or near-infrared wavelengths, but the team took up a challenge and looked at the thermal emissions from the object at wavelengths in a narrow window around 5 microns.

“I think everyone on the research team really believed that we were dreaming to think we could obtain a spectrum of this brown dwarf because its thermal glow is so feeble,” said Skemer. WISE 0855, is so cool and faint that many astronomers thought it would be years before a spectrum could be obtained. “I thought we’d have to wait until the James Webb Space Telescope was operating to do this,” Skemer said.

This spectroscopic view provided a glimpse into the environment of WISE 0855’s atmosphere. With the data in hand, the researchers then developed atmospheric models of the equilibrium chemistry for a brown dwarf at 250 degrees Kelvin and calculated the resulting spectra under different assumptions, including cloudy and cloud-free models. The models predicted a spectrum dominated by features resulting from water vapor, and the cloudy model yielded the best fit to the features in the spectrum of WISE 0855.

While the spectra of this object are strikingly similar to Jupiter, WISE 0855 appears to have a less turbulent atmosphere.

“The spectrum allows us to investigate dynamical and chemical properties that have long been studied in Jupiter’s atmosphere, but this time on an extrasolar world,” Skemer said.

The scientists say WISE 0855 looks more similar to Jupiter than any exoplanet yet discovered, which is especially intriguing since the Juno mission has just begun its exploration at the giant world. Jupiter, along with the other gas planets in our Solar System, all have clouds and storms, although Jupiter’s clouds are mainly made of ammonia with lower level clouds perhaps containing water. One of Juno’s goals is to determine the global water abundance at Jupiter.

Sources: UC Santa Cruz, Gemini

Posted on by Jason Major

Enceladus’ Jets Selectively Power-Up Farther From Saturn

Icy water vapor geysers erupting from fissures on Enceladus. Credit: NASA/JPL

A crowning achievement of the Cassini mission to Saturn is the discovery of water vapor jets spraying out from Enceladus‘ southern pole. First witnessed by the spacecraft in 2005, these icy geysers propelled the little 515-kilometer-wide moon into the scientific spotlight and literally rewrote the mission’s objectives. After 22 flybys of Enceladus during its nearly twelve years in orbit around Saturn, Cassini has gathered enough data to determine that there is a global subsurface ocean of salty liquid water beneath Enceladus’ frozen crust—an ocean that gets sprayed into space from long “tiger stripe” fissures running across the moon’s southern pole.  Now, new research has shown that at least some of the vapor jets get a boost in activity when Enceladus is farther from Saturn.

The gravitational pull of Saturn changes the amount of particles spraying from Enceladus at different points in its orbit. When it's farther from Saturn (left) the plume contains more icy particles and thus appears brighter. Credit: NASA/JPL-Caltech/University of Arizona/Cornell/SSI.
The gravitational pull of Saturn changes the amount of particles spraying from Enceladus at different points in its orbit. When it’s farther from Saturn (left) the plume contains more icy particles and thus appears brighter. Credit: NASA/JPL-Caltech/University of Arizona/Cornell/SSI.

By measuring the changes in brightness of a distant background star as Enceladus’ plumes passed in front of it in March 2016, Cassini observed a significant increase in the amount of icy particles being ejected by one particular jet source.

"Baghdad Sulcus," one of Enceladus' plume sources, imaged by Cassini during a close pass in Nov. 2011. (NASA/JPL/SSI)
“Baghdad Sulcus,” one of Enceladus’ plume sources, imaged by Cassini during a close pass in Nov. 2011. (NASA/JPL/SSI)

Named “Baghdad 1,” the jet went from contributing 2% of the total vapor content of the entire plume area to 8% when Enceladus was at the farthest point in its slightly-eccentric orbit around Saturn. This small yet significant discovery indicates that, although Enceladus’ plumes are reacting to morphological changes to the moon’s crust due to tidal flexing, it’s select small-scale jets that are exhibiting the most variation in output (rather than a simple, general increase in outgassing across the full plumes.)

“How do the tiger stripe fissures respond to the push and pull of tidal forces as Enceladus goes around its orbit to explain this difference? We now have new clues!” said Candice Hansen, senior scientist at the Planetary Science Institute and lead planner of the study. “It may be that the individual jet sources along the tiger stripes have a particular shape or width that responds most strongly to the tidal forcing each orbit to boost more ice grains at this orbital longitude.”

The confirmation that Enceladus shows an increase in overall plume output at farther points from Saturn was first made in 2013.

Whether this new finding means that the internal structure of the fissures is different than what scientists have suspected or some other process is at work either within Enceladus or in its orbit around Saturn still remains to be determined.

“Since we can only see what’s going on above the surface, at the end of the day, it’s up to the modelers to take this data and figure out what’s going on underground,” said Hansen.

Sources: Planetary Science Institute and NASA/JPL

Enceladus' water ice plumes were first observed by Cassini in 2005. (NASA/JPL/SSI)
Enceladus’ now-famous water ice plumes were first observed by Cassini in 2005. (NASA/JPL/SSI)
Posted on by Bob King

Spotlight On Pluto’s Frozen Polar Canyons

This enhanced color view Long canyons run vertically across the polar area—part of the informally named Lowell Regio, named for Percival Lowell, who founded Lowell Observatory and initiated the search that led to Pluto’s discovery. The widest of the canyons is about 45 miles (75 kilometers) wide and runs close to the north pole. Roughly parallel subsidiary canyons to the east and west are approximately 6 miles (10 kilometers) wide.
This enhanced color view Long canyons run vertically across the polar area—part of the informally named Lowell Regio, named for Percival Lowell, who founded Lowell Observatory and initiated the search that led to Pluto’s discovery. The widest of the canyons is about 45 miles (75 kilometers) wide and runs close to the north pole. Roughly parallel subsidiary canyons to the east and west are approximately 6 miles (10 kilometers) wide.
This enhanced color view shows long canyons running vertically across Pluto’s north polar region — part of the informally named Lowell Regio, named for Percival Lowell, who founded Lowell Observatory and initiated the search that led to Pluto’s discovery. The widest of the canyons is about 45 miles (75 km) wide and runs close to the north pole. Roughly parallel secondary canyons to the east and west are approximately 6 miles (10 km) wide. Click for a hi-res view. Credit: NASA/JHUAPL/SRI

Pluto’s frozen nitrogen custard “heart” has certainly received its share of attention. Dozens of wide and close-up photos homing on this fascinating region rimmed by mountains and badlands have been relayed back to Earth by NASA’s New Horizons probe after last July’s flyby. For being only 1,473 miles (2,370 km) in diameter, Pluto displays an incredible diversity of landscapes.

Annotated version of Pluto's north polar region.
Annotated version showing sinuous valleys, canyons and depressions and irregular-shaped pits. Credit: NASA/JHUAPL/SRI with additional annotations by the author

This week, the New Horizons team shifted its focus northward, re-releasing an enhanced color image of the north polar area that was originally part of a high-resolution full-disk photograph of Pluto. Inside of the widest canyon, you can trace the sinuous outline of a narrower valley similar in outward appearance to the Moon’s Alpine Valley, cut by a narrow, curvy rill that once served as a conduit for lava.

A composite of enhanced color images of Pluto (lower right) and Charon (upper left), taken by NASA's New Horizons spacecraft as it passed through the Pluto system on July 14, 2015. This image highlights the striking differences between Pluto and Charon. The color and brightness of both Pluto and Charon have been processed identically to allow direct comparison of their surface properties, and to highlight the similarity between Charon's polar red terrain and Pluto's equatorial red terrain. Pluto and Charon are shown with approximately correct relative sizes, but their true separation is not to scale.
A composite of enhanced color images of Pluto (lower right) and Charon, taken by NASA’s New Horizons spacecraft on July 14, 2015. This image highlights the striking differences between Pluto and Charon. The color and brightness of both Pluto and Charon have been processed identically to allow direct comparison of their surface properties, and to highlight the similarity between Charon’s polar red terrain and Pluto’s equatorial red terrain. Pluto and Charon are shown with approximately correct relative sizes, but their separation is not to scale. Credit: NASA/JHUAPL/SRI

We see multiple canyons in Pluto’s polar region, their walls broken and degraded compared to canyons seen elsewhere on the planet. Signs that they may be older and made of weaker materials and likely formed in ancient times when Pluto was more tectonically active. Perhaps they’re related to that long-ago dance between Pluto and its largest moon Charon as the two transitioned into their current tidally-locked embrace.

Cropped version showing three, odd-shaped pits that may reflect sinking of Pluto's crust. Credit:
Cropped version with arrows pointing to three, odd-shaped pits that may reflect sinking of Pluto’s crust. Credit: NASA/JHUAPL/SRI

In the lower right corner of the image, check out those funky-shaped pits that resemble the melting outlines of boot prints in the snow. They reach 45 miles (70 km) across and 2.5 miles (4 km) deep and may indicate locations where subsurface ice has melted or sublimated (vaporized) from below, causing the ground to collapse.

Notice the variation in color across the landscape from yellow-orange to pale blue. High elevations show up in a distinctive yellow, not seen elsewhere on Pluto, with lower elevations and latitudes a bluish gray. New Horizons’ infrared measurements show abundant methane ice across the Lowell Region, with relatively little nitrogen ice. The yellow terrains may be older methane deposits that have been more processed by solar UV light than the bluer terrain. The color variations are especially striking in the area of the collapse pits.

The new map shows exposed water ice to be considerably more widespread across Pluto's surface than was previously known - an important discovery.
The new map shows exposed water ice at Pluto to be considerably more widespread across its surface than was previously known. Its greatest concentration lies in the red-hued regions (in visual light) to the west of Tombaugh Regio, the large, heart-shaped feature. Credit: NASA/JHUAPL/SRI

Pluto’s icy riches include not only methane and nitrogen but also water, which forms the planet’s bedrock. NASA poetically refers to the water ice as “the canvas on which (Pluto’s) more volatile ices paint their seasonally changing patterns”. Recent images made in infrared light shows little or no water ice in the informally named places called Sputnik Planum (the left or western region of Pluto’s “heart”) and Lowell Regio. This indicates that at least in these regions, Pluto’s bedrock remains well hidden beneath a thick blanket of other ices such as methane, nitrogen and carbon monoxide.

To delve more deeply into Pluto, visit the NASA’s photojournal archive, where you’ll find 130 photos (and counting!) of the dwarf planet and its satellites.

Posted on by Fraser Cain

Did We Need the Moon for Life?

Did We Need the Moon for Life?

Astronomers hate the Moon because it ruins perfectly good observing nights. But is it possible that we all need the Moon for our very existence?

For all we know, Earth is the only place in the Universe where life appeared. This makes the mystery of our existence even more puzzling. What were all the factors required to bring about the first lifeforms on our planet, and encourage the evolution of more complex, intelligent lifeforms.

We needed a calm and reasonable Sun, solid ground, nice temperatures, the appropriate chemicals, and liquid water. Possibly drinks served in pineapples with little umbrellas. But what about the Moon? Is the Moon a necessity for life in any way?

To the best of our knowledge, our Moon was formed when a Mars-sized object smashed into the Earth about 4.5 billion years ago. This enormous collision spun out a cloud of debris that coalesced into the Moon we know and love today.

Back then, the Moon was much closer to the Earth than it is today, a mere 20-30,000 kilometers. A fraction of its current distance. If you could have stood on the surface of the Earth, the Moon would have looked 10 to 20 times bigger than we see it today.

But nobody did, because the Earth was a molten ball of red hot magma, tasty lava through and through. Life emerged 3.8 billion years ago, pretty much the day after Earth had cooled down to the point that it was possible for life to form.

Scientists think that it first formed in the oceans, where there were adequate temperatures and abundant water as a solvent for life’s chemicals to mix.

The effect of gravity is a cube of its distance. When the Moon was closer, the power of its gravity to pull the Earth’s water around was more ferocious. But what impact has this gravity had on our world and its life? Do we need the Moon to make the magic happen?

Turns out, we might owe our very existence to it because its pull of gravity might have set our plate tectonics in motion. Without plate tectonics, our planet might be more like Venus, toasty and dead.

Map of the Earth showing fault lines (blue) and zones of volcanic activity (red). Credit: zmescience.com
Map of the Earth showing fault lines (blue) and zones of volcanic activity (red). Credit: zmescience.com

It raises the level of the world’s oceans towards the equator. Without this gravity, the oceans would redistribute, raising levels at the poles. It has also slowed Earth’s rotation on its axis. Shortly after its formation, the Earth turned once every 6 hours. Without that Moon to slow us down, we’d have much more severe weather.

It stabilizes the Earth’s rotation on its axis. It’s possible that the Earth might have rolled over on its axis on a regular basis, causing a complete redistribution of the Earth’s water. Astronomers think this happened on Mars, because it never had a large Moon to stabilize it.

But the biggest impact that the Moon has on life is through tides. That regular movement of water that exposes the land at the edge of the ocean, and then covers it again just a few hours later. This could have encouraged life to adapt and move from the oceans to land.

One of the most subtle effects from the Moon is what it has done to life itself. Nocturnal animals behave differently depending on where the Moon is in the sky during its 29.5-day cycle. When the Moon is full and bright, prey fish stay hidden in the reef, when they’d be most visible.

Prey fish in the reef. Credit: Laslo Ilyes
Prey fish in the reef. Credit: Laslo Ilyes

Amazingly, lions are less likely to hunt during the full Moon, and researchers have found that lion attacks on humans happen 10 days after the full Moon, and many bats will be less active during the full Moon.

With so many species on Earth affected by the Moon, it’s reasonable to think that there would have been a different evolutionary direction for life on Earth over the eons, and humans might never have evolved.

It looks like the Moon is important after all. Important to the geology of Earth, and important to the evolution of life itself.

As extrasolar planet hunters search for new worlds, and determine their viability for life, they might want to focus on the worlds with moons first.

What impact has the Moon had on your life? Post your anecdotes in the comments!

Posted on by Fraser Cain

Weekly Space Hangout – Oct 2, 2015: Water on Mars, Blood Moon Eclipses, and More Pluto!

Host: Fraser Cain (@fcain)

Guests:

Morgan Rehnberg (cosmicchatter.org / @MorganRehnberg )
Pamela Gay (cosmoquest.org / @cosmoquestx / @starstryder)
Kimberly Cartier (@AstroKimCartier )
Brian Koberlein (@briankoberlein / briankoberlein.com)
Alessondra Springmann (@sondy)
Continue reading “Weekly Space Hangout – Oct 2, 2015: Water on Mars, Blood Moon Eclipses, and More Pluto!”

Posted on by Fraser Cain

Do Astronauts Drink their Pee?

Do Astronauts Drink their Pee?

In order to fly in space, astronauts need to make a few sacrifices, like drink their own urine. Yuck? Don’t worry, it’s totally safe.

Astronauts are a resourceful bunch. They’re the best of the best of the best of the best. They’re ready to do whatever it takes to get the job done. WHATEVER IT TAKES, INCLUDING DRINKING PEE. They live on the International Space Station for the better part of a year, where air, food and water are precious resources. Sometimes you take a hit for the team back.

Every drop of water on the International Space Station was carried there from Earth, by rocket, possibly in someone’s bladder. The cost of launching a single kilo into orbit can be over $10 grand. Do a little back of the tp math and the value of a single kilogram of water in space is worth almost as much as a kilogram of yellow gold here on Earth.

That’s actual money gold, and not pee joke gold. The punchline is astronauts need to conserve water. For the longest time, there wasn’t any way to take conservation to the “next level”. All the “waste water” including pee produced on the station was just held, possibly uncomfortably and resulting in dancing, and it needed to be disposed of.

In 2009, NASA got serious about conserving water and launched the Water Recovery System to the International Space Station. What is it with you guys and names? I would have shot for “Precycling Internal Solution System” just for the acronym. In fact, that’s what we’re using now.

Ever since, astronauts have been drinking their own urine like Captain Redbeard Rum on Blackadder. Generally after it’s been purified by the recovery system, or if you prefer “peecycled”. Outside of that I’m sure accidents happen, and whatever they get up to in their own time is their business.

Speaking of which, Here’s a video of beloved Canadian astronaut Chris Hadfield demonstrating the P.I.S.S system. It takes all water vapor, sweat, and grey water produced and excreted by astronauts and turns it back into drinkable water.

On Earth, you can clear dirty water by boiling it. Collect your steam on a cold surface, pure, pee free and ready for drinking again. Pro tip, this process actually requires gravity, which isn’t readily available when you’re in free fall.

The Recovery System looks like a big spinning keg, which creates artificial gravity. It’s heated and steam is produced. Dirt and contaminants such as the most purified pee molecules are pushed to the edges of the drum while the steam is carried away.

NASA's Water Recovery System. Credit: NASA
NASA’s Water Recovery System. Credit: NASA

The artificial gravity isn’t perfect, and only 93% of the water can be recovered this way. This means that dirty waste water builds up inside the space station and needs to be flushed with the rest of the trash. Astronauts can’t peecycle everything on the space station, trash does build up. They’ve got a solution for this too.

The most recent cargo delivery spacecraft is always left attached to the space station. Instead of doing laundry, which would use up their precious water and is super boring. Seriously, if you went to the trouble of sending me to space and asked to me wash my clothes I’d get a little snippy.

Astronauts do what the rest of us only dream about. They just wear their clothes until they’re totally worn out. Then throw their laundry into the excess module. Once it’s completely filled with pee, laundry, food remnants, and other, uh… stuff, the spacecraft detaches from the station and re-enters the Earth’s atmosphere where it’s incinerated. No fuss, no muss. Also, clearly for this episode, we’re only going as far as pee jokes as poop jokes are off the table.

Yes, astronauts are drinking their pee. They close their eyes and remind themselves it’s just pure water. Completely safe and delicious to drink. No pee molecules left here. As astronaut Koichi Wakata said, “Here on board the ISS, we turn yesterday’s coffee into tomorrow’s coffee”.

Would you be willing to drink the water produced by the Water Recovery System? Tell us in the comments below.