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News of Venice, CA and Marina del Rey CA

Steep Slopes on Mars Reveal Structure of Buried Ice

NASA
A cross-section of underground ice is exposed at the steep slope that appears bright blue in this enhanced-color view from the HiRISE camera on NASA’s Mars Reconnaissance Orbiter. The scene is about 550 yards wide. The scarp drops about 140 yards from the level ground in the upper third of the image. Image Credit: NASA/JPL-Caltech/UA/USGS.

Note: This is based on a press release from NASA/JPL.

Bob Eklund1.5

Bob Eklund Looking-Up Column

 

A cross-section of underground ice is exposed at the steep slope that appears bright blue in this enhanced-color view from the HiRISE camera on NASA’s Mars Reconnaissance Orbiter. The scene is about 550 yards wide. The scarp drops about 140 yards from the level ground in the upper third of the image. Image Credit: NASA/JPL-Caltech/UA/USGSResearchers using NASA’s Mars Reconnaissance Orbiter (MRO) have found eight sites where thick deposits of ice beneath Mars’ surface are exposed in faces of eroding slopes.

These eight scarps, with slopes as steep as 55 degrees, reveal new information about the internal layered structure of previously detected underground ice sheets in Mars’ middle latitudes.

The ice was likely deposited as snow long ago. The deposits are exposed in cross section as relatively pure water ice, capped by a layer one to two yards thick of ice-cemented rock and dust. They hold clues about Mars’ climate history. They also may make frozen water more accessible than previously thought to future robotic or human exploration missions.

“There is shallow ground ice under roughly a third of the Martian surface, which records the recent history of Mars,” said the study’s lead author, Colin Dundas of the U.S. Geological Survey’s Astrogeology Science Center in Flagstaff, Arizona. “What we’ve seen here are cross-sections through the ice that give us a 3-D view with more detail than ever before.”

The discovery reported today gives us surprising windows where we can see right into these thick underground sheets of ice,” said Shane Byrne of the University of Arizona Lunar and Planetary Laboratory, Tucson, a co-author on today’s report.

The new study identifies eight sites where ice is directly accessible, at latitudes with less hostile conditions than at Mars’ polar ice caps. “Astronauts could essentially just go there with a bucket and a shovel and get all the water they need,” Byrne said.

Solar System’s First Interstellar Visitor Dazzles Scientists

Artist’s impression of the interstellar asteroid `Oumuamua
European Southern Observatory/M.Kornmesser

Bob Eklund Looking Up

Bob Eklund
Looking Up

Astronomers recently scrambled to observe an intriguing asteroid that is passing through our solar system on a steep trajectory from interstellar space—the first confirmed object from another star.

Now, new data reveal the interstellar interloper to be a rocky, cigar-shaped object with a somewhat reddish hue. The asteroid, named ‘Oumuamua by its Hawaiian discoverers, is up to one-quarter mile long and highly-elongated—perhaps 10 times as long as it is wide. That aspect ratio is greater than that of any asteroid or comet observed in our solar system to date.

The observations and analyses suggest this unusual object had been wandering through the Milky Way, unattached to any star system, for hundreds of millions of years before its chance encounter with our star system.

Immediately after its discovery, telescopes around the world, including ESO’s Very Large Telescope in Chile, were called into action to measure the object’s orbit, brightness and color. Urgency for viewing from ground-based telescopes was vital to get the best data.

Combining the images from the ESO telescope with those of other large telescopes, a team of astronomers led by Karen Meech of the Institute for Astronomy in Hawaii found that ‘Oumuamua varies in brightness by a factor of 10 as it spins on its axis every 7.3 hours. No known asteroid or comet from our solar system varies so widely in brightness, with such a large ratio between length and width. The most elongated objects we have seen to date are no more than three times longer than they are wide.

Meanwhile, in a galaxy not so far, far away…

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Note: This is a press release from NASA/JPL.

Kepler

The fantasy creations of the “Star Wars” universe are strikingly similar to real planets in our own Milky Way galaxy. A super-Earth in deep freeze? Think ice-planet Hoth. And that distant world with double sunsets can’t help but summon thoughts of sandy Tatooine.

The most recently revealed exoplanet possessing Earth-like properties, Kepler-452b, might make a good stand-in for Coruscant—the high-tech world, seen in several Star Wars films, whose surface is encased in a globe-spanning city. Kepler-452b belongs to a star system 1.5 billion years older than Earth’s. That would give an advanced civilization more than a billion-year jump on us. The denizens of Coruscant not only have an entirely engineered planetary surface, but an engineered climate as well. On Kepler-452b, conditions are growing warmer as its star’s energy output increases—a symptom of advanced age. If this planet (which is 1.6 times the size of Earth) is truly Earth-like, some climate engineering might be needed there as well.

The planet Mustafar, scene of an epic duel between Obi-Wan Kenobi and Anakin Skywalker in “Revenge of the Sith,” has a number of exoplanet counterparts. These molten, lava-covered worlds, such as Kepler-10b and Kepler-78b, are rocky planets in Earth’s size range whose surfaces could well be perpetual infernos.

The planet OGLE-2005-BLG-390, nicknamed “Hoth,” is a cold super-Earth, with a mass five times that of Earth and a surface temperature estimated at minus 364 degrees Fahrenheit. That most likely means no Hoth-style tauntauns to ride, or even formidably fanged abominable snowmen (aka wampas). Astronomers used an extraordinary planet-finding technique known as microlensing to find this world in 2005—one of the early demonstrations of this technique’s ability to reveal exoplanets. In microlensing, backlight from a distant star is used to reveal planets around a star closer to us

Luke Skywalker’s home planet, Tatooine, is said to possess a harsh, desert environment, swept by sandstorms as it roasts under the glare of twin suns. Real exoplanets in the thrall of two or more suns likely have even harsher environments. Kepler-16b was the Kepler telescope’s first discovery of a planet in a “circumbinary” orbit—circling both stars, as opposed to just one, in a double-star system. This planet, however, is likely cold, about the size of Saturn, and gaseous, though partly composed of rock. It lies outside its two stars’ “habitable zone,” where liquid water could exist, and its stars are cooler than our sun—all of which probably adds up to a lifeless Tatooine.

Endor, the forested realm of the Ewoks introduced in “Return of the Jedi.” is a moon orbiting a gas giant. Detection of exomoons—moons circling distant planets—is still in its infancy for scientists here on Earth. A possible exomoon was observed in 2014 via microlensing. It will remain forever unconfirmed, however, since each microlensing event can be seen only once. If the exomoon is real, it orbits a rogue planet, unattached to a star and wandering freely through space. The planet might have hung on to its moon after somehow being ejected during the early history of a forgotten planetary system.

The hunt for exomoons could actually have powerful implications in the search for life beyond Earth. If exomoons are shown to be potentially habitable, this would open another avenue for biology; habitable moons might even outnumber habitable planets. Could they have bustling ecosystems, with life forms even more exotic than Endor’s living teddy bears, swinging between trees Tarzan-style? Stay tuned.

Ceres’ Bright Spots Similar to Epsom Salt

Looking Up500_000001

Note: This is a press release from NASA/JPL.

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This representation of Ceres’ Occator Crater in false colors shows differences in the surface composition. Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Dwarf planet Ceres reveals some of its well-kept secrets in a study published in the journal Nature, thanks to new data from NASA’s Dawn spacecraft. They include highly anticipated insights about mysterious bright features found all over the dwarf planet’s surface and especially in the crater Occator.

Ceres has more than 130 bright areas, and most of them are associated with impact craters. Study authors, led by Andreas Nathues at Max Planck Institute for Solar System Research, Göttingen, Germany, write that the bright material is consistent with a type of magnesium sulfate called hexahydrite. A different type of magnesium sulfate is familiar on Earth as Epsom salt.

Nathues and colleagues, using images from Dawn’s framing camera, suggest that these salt-rich areas were left behind when water-ice sublimated in the past. Impacts from asteroids would have unearthed the mixture of ice and salt.

“The global nature of Ceres’ bright spots suggests that this world has a subsurface layer that contains briny water-ice,” Nathues said.

The surface of Ceres, whose average diameter is 584 miles, is generally dark—similar in brightness to fresh asphalt. The bright patches that pepper the surface represent a large range of brightness, with the brightest areas reflecting about 50 percent of sunlight shining on the area. But there has not been unambiguous detection of water ice on Ceres; higher-resolution data are needed to settle this question.

The inner portion of the crater called Occator contains the brightest material on Ceres. Occator itself is 60 miles in diameter, and its central pit, covered by this bright material, measures about 6 miles wide and 0.3 mile deep. Dark streaks, possibly fractures, traverse the pit. Remnants of a central peak, which was up to 0.3 mile high, can also be seen.

With its sharp rim and walls, and abundant terraces and landslide deposits, Occator appears to be among the youngest features on Ceres. Dawn mission scientists estimate its age to be about 78 million years old.

Study authors write that some views of Occator appear to show a diffuse haze near the surface that fills the floor of the crater. This may be associated with the observations of water vapor at Ceres that were reported by the Herschel space observatory in 2014. The haze seems to be present in views taken at noon local time and absent at dawn and dusk. This suggests that the phenomenon resembles the activity at the surface of a comet, with water vapor lifting tiny particles of dust and residual ice. Future data and analysis may test this hypothesis and reveal clues about the process causing this activity.

Daytime surface temperatures on Ceres span from minus 136 degrees to minus 28 degrees Fahrenheit. The maximum temperatures were measured in the equatorial region. The temperatures at and near the equator are generally too high to support ice at the surface for a long time, but data from Dawn’s next orbit will reveal more details.

As of this week, Dawn has reached its final orbital altitude at Ceres, about 240 miles from the surface of the dwarf planet. In mid-December, Dawn will begin taking observations from this orbit—including images at a resolution of 120 feet per pixel; infrared, gamma ray and neutron spectra; and high-resolution gravity data.