Tag: science

There were Viking cats

12:02 am

News you can use: New research now suggests that cats spread through human society, with the second wave involving sea-faring people such as the Vikings.

The first wave is a story you’re probably familiar with. When the team looked the mitochondrial DNA – genetic information that’s passed on from the mother only – they found that wild cats from the Middle East and the fertile eastern Mediterranean shared a similar mitochondrial lineage.

This suggests that small wild cats spread through early agricultural communities, because they were attracted to the mice that were attracted to the grains. The farmers likely encouraged their presence, because, let’s face it, those rodent-killing machines would have been mighty cute company.

Then, thousands of years after this, the research points to a separate mitochondrial connection between cats descended from those in Egypt to ones in Eurasia and Africa. “A mitochondrial lineage common in Egyptian cat mummies from the end of the 4th century BC to the 4th century AD was also carried by cats in Bulgaria, Turkey and sub-Saharan Africa from around the same time,” Callaway reports.

This second wave of expansion has been attributed to ancient sea-faring people – farmers, sailors, and Vikings – because the cats were likely encouraged to stay on board to keep their rodent problem in check.

It makes perfect sense. Our ruling lords needed more space, and thus they compelled humans to begin the great explorations that eventually allowed them to conquer the western hemisphere, as well as the internet.

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Scientists create coldest spot ever on ISS

5:29 pm

Using a compact lab called the Cold Atom Lab and launched to ISS in a Cygnus freighter in May, scientists have now successfully created coldest spot ever.

The government agency created atoms known as Bose-Einstein condensates (BECs) for the first time in orbit to focus on their unusual quantum behavior. A team of astronauts on the International Space Station (ISS) was able to take the Cold Atom Lab (CAL), which was loaded with lasers and a vacuum chamber, to understand how BECs interact with gravity.

…The scientists produced the BECs with temperatures as “as low as 100 nanoKelvin, or one ten-millionth of one Kelvin above absolute zero,” NASA added, in the statement. Zero Kelvin, also known as absolute zero, is the equivalent of minus 459 degrees Fahrenheit. The average temperature of space is approximately 3 Kelvin or minus 454 degrees Fahrenheit.

In a sense, they didn’t so much create a cold spot as create conditions that allowed the Bose-Einstein condensates to form so that they could study them. The article provides some background about this research, which is focused mostly on trying to figure out how to unify quantum mechanics (which explains the interactions at the atomic level) with general relativity (which explains the actions of matter and energy at large scales). Physicists have been trying unify both for decades, with little success.

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Weird Martian crater?

1:17 pm

Weird crater on Mars

Time for another cool image! The image on the left, cropped to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on May 31, 2018, and shows a very strange layered mesa sitting in what looks like a crater or collapse feature. If you click on the image you can see the entire picture.

The location of this image is out in the middle of the vast northern plains of Mars. This region has few pronounced features, and generally sits at a lower elevation to the rest of Mars. It is suspected by some scientists that an intermittent ocean was once here, and that we are looking at the floor of a now dry sea.

This image was part of the July image release from MRO, and thus included no caption. They simply refer to it as a layered feature. It sits about a half mile (about 800 meters) to the west of a rough and indistinct cliff that drops down into an area of rougher terrain. This suggests that if this was formed by an impact, it cut down into that lower rougher layer, and since the impact there has been some upwelling from below creating the layered mesa.

I would not take my hypothesis very seriously, however. This feature could have nothing to do with an impact. It might also have been a mesa that now sits in a collapsed sinkhole. Or not. I could come up with many theories, all of which are likely wrong. What I do see here is something that geologically is very strange and baffling.

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Perseid meteor shower this weekend

10:24 am

The annual Perseid meteor shower upcoming on August 12 is expected to be especially good this year because there will be no moon in the sky.

The Perseid meteors seem to come from a single point, the `radiant’, situated in the constellation Perseus, giving the shower its name. This is however just an effect of perspective, as the meteors move parallel to each other, much like drivers see when driving in heavy rain.

The radiant will be visible from around 10pm and at this time there will be the highest chance of seeing `Earth grazing meteors’. These are meteors that skim the Earth’s atmosphere and so have long, blazing tails.

Observers can expect to see a few tens of meteors per hour, or one every few minutes, once darkness has fallen on 12 August. The number of meteors will peak in the early hours of 13 August, when up to around seventy each hour should be visible.

It is worth it to find a nice dark place and stay up all night at least once in your life to watch this shower. Get a nice camp chair that allows you to lie back, make sure you are dressed comfortably, and sit back and enjoy.

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True color images of Pluto and Charon

9:24 am

The New Horizons science team has released mosaic global images of Pluto and Charon, calibrated to capture their true colors as closely as possible.

These natural-color images result from refined calibrations of data gathered by New Horizons’ Multispectral Visible Imaging Camera (MVIC).”That processing creates images that would approximate the colors that the human eye would perceive – bringing them closer to ‘true color’ than the images released near the encounter,” said Alex Parker, a New Horizons science team co-investigator from Southwest Research Institute, Boulder, Colorado.

Because MVIC’s color filters don’t closely match the wavelengths sensed by human vision, mission scientists applied special processing to translate the raw MVIC data into an estimate of the colors that the eye would see. The colors are more subdued than those constructed from the raw MVIC color data, because of the narrower wavelength range sensed by the human eye.

Both images were taken as New Horizons zipped toward closest approach to Pluto and its moons on July 14, 2015; Charon was taken from a range of 46,091 miles (74,176 kilometers) and Pluto from 22,025 miles (35,445 kilometers). Each is a single color MVIC scan, with no data from other New Horizons imagers or instruments added. The striking features on each are clearly visible, from Charon’s reddish north-polar region known as Mordor Macula, to the bright expanse of Pluto’s, nitrogen-and-methane-ice rich “heart,” named Sputnik Planitia.

I must add that these images show only one hemisphere, since the New Horizons flyby did not get a good look at the opposite hemisphere. We won’t know what the other half of both planets look like for many decades.

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The shrinking and growth of the poles of Mars

9:19 am

Using infrared data from several Mars orbiters over a period of a full Martian year, equivalent to two Earth years, scientists have created an animation showing the growth and retreat and regrowth of the carbon dioxide icecaps of the red planet’s two poles.

This animation shows a side-by-side comparison of CO2 ice at the north (left) and south (right) Martian poles over the course of a typical year (two Earth years). This simulation isn’t based on photos; instead, the data used to create it came from two infrared instruments capable of studying the poles even when they’re in complete darkness.

As Mars enters fall and winter, reduced sunlight allows CO2 ice to grow, covering each pole. While ice at the north pole is fairly symmetrical, it’s somewhat asymmetrical during its retreat from the south pole for reasons scientists still don’t understand. Scientists are especially interested in studying how global dust events affect the growth and retreat of this polar ice. Mars’ seasons are caused by a tilt in the planet, resulting in winter at one of the planet’s poles while it’s summer at the other.

I have embedded the animation below the fold.
» Read more

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Aristarchus Crater on the Moon

9:08 am

Aristarchus Crater

Cool image time! The image on the right, reduced in resolution to post here, shows Aristarchus Crater, one of the more geological intriguing locations on the Moon. This oblique image was taken by Lunar Reconnaissance Orbiter (LRO), still operating in lunar orbit. If you click on the image you can see the full resolution image.

Aristarchus crater is 40 kilometers (25 miles) in diameter and 2700 meters (1.7 miles) deep, with a central peak that rises 300 meters (almost a thousand feet) above the crater floor. When LRO pointed back towards the Sun, LROC was able to capture this magnificent view highlighting subtle differences in albedo (brightness). Some of the albedo contrast is due to maturity (young material is generally brighter than older material) and some reveal true differences in rock type. The central peak shows the complexity of what lies beneath the now hardened impact melt sea that filled the bottom of the crater.

The best part however is the close-up they provided of the crater’s central peaks, posted below.
» Read more

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Tess captures comet, variable stars, asteroids, and Martian light

8:44 am

During its testing period prior to beginning science operations this month, the exoplanet space telescope TESS spotted in one series of images a comet, a host of variable stars, some asteroids, and even the faint hint of some reflected light from Mars.

Over the course of these tests, TESS took images of C/2018 N1, a comet discovered by NASA’s Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) satellite on June 29. The comet, located about 29 million miles (48 million kilometers) from Earth in the southern constellation Piscis Austrinus, is seen to move across the frame from right to left as it orbits the Sun. The comet’s tail, which consists of gases carried away from the comet by an outflow from the Sun called the solar wind, extends to the top of the frame and gradually pivots as the comet glides across the field of view.

In addition to the comet, the images reveal a treasure trove of other astronomical activity. The stars appear to shift between white and black as a result of image processing. The shift also highlights variable stars — which change brightness either as a result of pulsation, rapid rotation, or by eclipsing binary neighbors. Asteroids in our solar system appear as small white dots moving across the field of view. Towards the end of the video, one can see a faint broad arc of light moving across the middle section of the frame from left to right. This is stray light from Mars, which is located outside the frame. The images were taken when Mars was at its brightest near opposition, or its closest distance, to Earth.

The video that was compiled from these images is embedded below the fold.
» Read more

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Sunspot update for July 2018: The Sun flatlines!

10:50 am

Yesterday NOAA posted its monthly update of the solar cycle, covering sunspot activity for July 2018. As I do every month, I am posting it below, annotated to give it some context.

This might be the most significant month of solar activity that has been observed since Galileo. Except for two very short-lived and very weak sunspots that observers hardly noted, the Sun was blank for entire month of July. This has not happened since 2009, during the height of the last solar minimum.

What makes this so significant and unique is that it almost certainly signals the return of the next solar minimum, a return that comes more than a year early. The solar cycle the Sun is now completing has only been ten years long. It is also one of the weakest in more than a hundred years. This combination is unprecedented. In the past such a weak cycle required a long cycle, not a short one.
» Read more

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Rogue giant exoplanet or brown dwarf discovered about 20 light years away

5:16 pm

Using the Jansky VLA radio telescope astronomers have detected evidence of rogue giant exoplanet or brown dwarf about 20 light years away

Astronomers using the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) have made the first radio-telescope detection of a planetary-mass object beyond our Solar System. The object, about a dozen times more massive than Jupiter, is a surprisingly strong magnetic powerhouse and a “rogue,” traveling through space unaccompanied by any parent star.

“This object is right at the boundary between a planet and a brown dwarf, or ‘failed star,’ and is giving us some surprises that can potentially help us understand magnetic processes on both stars and planets,” said Melodie Kao, who led this study while a graduate student at Caltech, and is now a Hubble Postdoctoral Fellow at Arizona State University.

The data is not sufficient yet to determine whether this is an exoplanet or a brown dwarf. It is big, and it is floating independent of any other objects, which makes it interesting in of itself.

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Mars dust storm blocks Mars Reconnaissance Orbiter images

9:29 am

In my normal routine to check out the periodic posting of new high resolution images from Mars Reconnaissance Orbiter (MRO), the August 1 update brought what at first was a disturbing surprise. If you go to the link you will see that a large majority of the images show nothing by a series of vertical lines, as if the high resolution camera on MRO has failed.

Yet, scattered among the images were perfectly sharp images. I started to look at these images to try to figure out the differences, and quickly found that the sharp images were always of features in high latitudes, while the blurred images were closer to the equator.

The August 1 image release covered the June/July time period, when the on-going Martian dust storm was at its height. The images illustrate also where the storm was most opaque, closer to the equator.

The next few updates, which occur every three weeks or so, should show increasing clarity as the storm subsides. And the storm is subsiding, according to the latest Opportunity update. The scientists have still not re-established contact with the rover, and do not expect to for at least a month or more, but they are finding that the atmospheric opacity at Endeavour Crater seems to be dropping.

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More close-up images of Ceres

9:19 am

Dome and fractures in Occator Crater

Strange image time! The Dawn science team today released a set of new images taken by the spacecraft in its new very close orbit of Ceres. The image on the right is a cropped section of one of those images, and shows some fractures and a dome in Occator Crater. The image was taken from 28 miles altitude, and if you click on it you can see the entire photograph.

What immediately stands out in this image is the strange bright flow on top of the dome. At first glance it looks like someone put a seashell there. In reality I think it is showing us a landslide of bright material flowing downward, towards the top of the image. The flow was significant enough that it piled up as it went down, which is why it created a cliff edge and shadow line at its base.

Everything we see here is influenced by Ceres’s tiny gravity. It is not unusual to see fractures in the floor of a crater, the nature of these fractures and domes is different, and will require a lot of work by scientists to interpret, because of the different environment.

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No water as yet detected on Ryugu

9:05 am

The Hayabusa-2 science team today said that their first preliminary survey of Ryugu has yet to detect evidence of water.

The Japan Aerospace Exploration Agency (JAXA) said Aug. 2 that data collected from the space probe showed no water on the boulders scattered on the surface of Ryugu.

Ryugu is a C-type asteroid, which is rich in carbon. Many C-type asteroids are known to contain moisture in their surface boulders, and experts hoped that Ryugu would be one of them.

Hayabusa-2’s visit has just begun. I still expect surprises.

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Landslide on Mars

12:45 pm

Landslide on Mars

Cool image time! The image on the right, cropped and reduced in resolution to post here, was taken by Mars Reconnaissance Orbiter on May 30, 2018. It shows the remains of a landslide where it appears a huge chunk of the cliff face broke off and then flowed downward, pushing ahead of it more material to produce a tongue of debris more than four miles long. (If you click on the image you can see the full photograph.)

The picture invokes a spectacular single event. When the cliff broke off, it hit the ground below it like a rock would in wet beach mud. Like wet sand, the ground was pushed away in a muddy gloppy mess.

Is this terrain wet however? The location of this landslide provides some intriguing geological context. Below are two context images, showing this landslide’s location on Mars.
» Read more

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Planetary scientists protest use of term “Planet Nine” for unknown planet

9:13 am

A group of planetary scientists have protested the recent use by some of the term “Planet Nine” for the unknown large planet some believe remains undiscovered in an orbit beyond Pluto.

“We the undersigned wish to remind our colleagues that the IAU planet definition adopted in 2006 has been controversial and is far from universally accepted. Given this, and given the incredible accomplishment of the discovery of Pluto, the harbinger of the solar system’s third zone — the Kuiper Belt — by planetary astronomer Clyde W. Tombaugh in 1930, we the undersigned believe the use of the term ‘Planet 9’ for objects beyond Pluto is insensitive to Professor Tombaugh’s legacy.

“We further believe the use of this term should be discontinued in favor of culturally and taxonomically neutral terms for such planets, such as Planet X, Planet Next or Giant Planet Five.”

The planetary scientist community, the people who really should be the ones to determine the proper definition of a planet, has never accepted the IAU planet definition. This protest letter is just more evidence of this fact.

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Close-up of bright spot in Occator Crater

3:35 pm

Vinalia Faculae in Occator Crater

Cool image time! The Dawn science team today released some new images taken by the spacecraft in its final tight orbit around the dwarf planet Ceres. The image on the right is a cropped section of the full image. It shows some interesting details of part of one of the two bright spots in Occator Crater, dubbed Vinalia Facula, and was taken from a distance of 36 miles.

Other images show small bright spots in another small crater, fractures and interesting patterns in the floor of Occator crater, a dome in Occator Crater suggestive of underground processes pushing up, and other close-ups of its crater walls.

While all of these features are reminiscent of geology on Earth, none are really the same. Ceres’ light gravity and harsh environment, plus its history in the asteroid belt, requires alien processes that only hint at similarities to what we see on Earth.

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A vegetable grater on Mars

1:44 pm

A vegetable grater on Mars

Cool image time! I honestly can’t think of any better term but “vegetable grater” to describe the strange surface in the image on the right, cropped from the full sized image that was released with the July 11, 2018 monthly release of new images from the high resolution camera on Mars Reconnaissance Orbiter (MRO).

If you click on the image you can see the whole image, which merely shows more of the same terrain over a wider area. When I cropped it, I literally picked a random 450×450 pixel-sized area, since other than slight variations the entire terrain in the full image is as equally rough. The resolution captures objects as big as five feet across.

Looking at the full image there does seem to be flow patterns moving across the middle of the image, but if so these flow patterns had no effect on the surface roughness, other than indicating a very slight difference in the size of the knobs and pits. Overall, very strange.

The location of this place on Mars is in the cratered southern highlands, to the southwest of Hellas Basin, as indicated by the black cross in the image below.
» Read more

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Two roundworms return to life after being frozen for almost 42,000 years

10:25 am

Russian scientists have successfully brought two roundworms back to life after being frozen for almost 42,000 years.

Russian scientists said the two prehistoric worms, out of a group of about 300, are moving and eating after they came back to life in a lab at the Institute of Physico-Chemical and Biological Problems of Soil Science in Moscow, the Siberian Times reported. “After being defrosted, the nematodes showed signs of life,” a report from the Russian scientists said, according to the Siberian Times.

One of the worms was found near the Alazeya River in 2015 and is believed to be about 41,700 years old, according to the study published in the Doklady Biological Sciences. They were found about 11.5 feet underground.

The other worm was found in 2002 in a fossil rodent burrow near the Kolyma River. These samples were taken from about 100 feet underground.

If confirmed, this result is not only astonishing, it has significant implications, as it suggests that the science fiction idea of freezing people for long interstellar flights might actually be possible, eventually.

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House committee approves new space weather bill

9:25 am

The House Science Committee yesterday approved new space weather bill that would shift responsibility for coordinating the government’s space weather observation capabilities to the National Space Council, while also creating a pilot commercial program for launch weather satellites.

It appears there was some heavy political maneuvering involved with this bill, as there was a late switch of language that changed its focus.

The new text has a strong focus on the private sector. In the policy section, for example, it explicitly states that “space weather observation and forecasting are not exclusive functions of the Federal Government” and the government “should, as practicable, obtain space weather data and services through contracts with the commercial sector, when the data and services are available, cost-effective, and add value.” The bill requires the Secretary of Commerce to establish a pilot program for obtaining space weather data from the private sector that appears analogous to NOAA’s commercial weather data pilot program.

The Senate will still have to review and approve this new bill.

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NASA wants to delay WFIRST to pay for Webb overruns

9:07 am

In testimony to Congress yesterday NASA administrator Jim Bridenstine said that the agency wants to delay the Wide Field Infrared Space Telescope to pay for the new cost overruns of the James Webb Space Telescope.

Bridenstine said during the hearing that no decisions had been made on how to cover those additional JWST costs. “By the 2020 timeframe is when we’re going to need to have additional funds. So between now and then we’re going to have to make determinations,” he said. “Right now that process is underway.”

He said those decisions would consider the guidance from decadal surveys and a desire to maintain a balanced portfolio of programs. He specifically assured one member, Rep. Mo Brooks (R-Ala.), that the extra funding would not come out of human spaceflight programs, particularly the Space Launch System. “This is relevant to the Science Mission Directorate exclusively, and that’s where, at this point, we’ve had discussions about what are the options going forward,” Bridenstine said.

Committee members used the two-and-a-half-hour hearing to express their frustrations with this latest delay, noting that the original concept for the mission [Webb] called for it to cost $500 million and launch in 2007, versus a current lifecycle cost of $9.6 billion and launch in 2021. “This is 19 times the original cost and a delay of 14 years,” said Rep. Lamar Smith (R-Texas), chairman of the committee. “It doesn’t get much worse than that.” [emphasis mine]

Only yesterday I speculated that the cuts to WFIRST were related to Webb. It turns out I was right.

I have highlighted above one detail revealed at the hearing. I have always thought Webb’s initial budget was $1 billion with a launch date of 2011. It appears it was less, by half, and it was supposed to launch four years sooner. Makes this boondoggle even more of an embarrassment for NASA and the astrophysics community. And for the astrophysics community it is also a disaster, because Webb’s overruns for the past two decades essentially wiped out what had been a very vibrant space astronomy program at NASA.

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Ryugu as seen by Hayabusa-2 from less than 4 miles

8:41 am

Ryugu from less than 4 miles distance

The image on the right as a cropped section of an image taken by Hayabusa-2 from only 3.7 miles distance from the asteroid Ryugu. If you click on the link you can see the full image. I picked this section to crop out because it shows the asteroid’s limb, an interesting boulder field, and part of a the asteroid’s largest crater, on the lower right. As noted by the Hayabusa-2 science team in describing details in the full image:

The resolution in Figure 1 is about 3.4 times higher than the images taken from the Home Position [20 kilometers distance] so far. 1 pixel in Figure 1 corresponds to about 60cm. The largest crater on the surface of Ryugu is situated near the center of the image and you can see that it has a shape like a “mortar”. You can also see that the surface of Ryugu is covered with a large number of boulders. This picture will provide important information as we choose the landing site.

The smallest objects visible are thus about two feet across.

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NOAA still struggling to get GOES 17 working

1:12 pm

NOAA is still struggling to pinpoint and correct the problem in GOES 17, launched in March, that prevents it from taking certain infrared weather images.

In a teleconference with reporters, NOAA officials said they had been able to improve the availability of infrared and near-infrared channels on the Advanced Baseline Imager (ABI) instrument on the GOES-17 satellite since the agency first reported the problem two months ago. The spacecraft, originally known as GOES-S, launched in March. “ABI is already demonstrating improved performance from what was initially observed,” said Pam Sullivan, director of the GOES-R system program. Currently, 13 of the instrument’s 16 channels are available 24 hours a day, with the other three able to operate at least 20 hours a day.

That will change, though, on a seasonal basis, depending on the amount of sunlight that shines into the instrument. By September, the hottest part of the orbit, only 10 of 16 channels will be available 24 hours a day, she said, with the other six available “most of the day.”

The satellite is second satellite launched out of a four satellite constellation that NOAA is building for $11 billion. They have now also admitted that the same problem exists on the first satellite, but does not seem to be effecting performance in the same way.

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NASA delays launch of Parker Solar probe, again

9:41 am

For the second time NASA has delayed the launch of the Parker Solar probe due to issues related to the Delta IV Heavy rocket.

The United Launch Alliance Delta IV Heavy was originally scheduled to launch the Parker Solar Probe on Aug. 4, before what NASA described as “a minor tubing leak” was discovered at the processing facility in Titusville. The launch slipped to Aug. 6 and now NASA and its mission partners are targeting Aug. 11 for a 45-minute launch window at 3:48 a.m. from Cape Canaveral Air Force Station.

The latest delay comes after “a small strip of foam was found inside the (spacecraft) fairing,” during final inspections after the spacecraft was encapsulated in the Delta IV Heavy nose cone, according to NASA.

The launch window closes on August 19, so there better not be many more problems.

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Liquid water found beneath Martian south pole

9:32 am

Data from Europe’s Mars Express orbiter has detected a pond of liquid water buried beneath the Martian south pole.

The radar investigation shows that south polar region of Mars is made of many layers of ice and dust down to a depth of about 1.5 km in the 200 km-wide area analysed in this study. A particularly bright radar reflection underneath the layered deposits is identified within a 20 km-wide zone.

Analysing the properties of the reflected radar signals and considering the composition of the layered deposits and expected temperature profile below the surface, the scientists interpret the bright feature as an interface between the ice and a stable body of liquid water, which could be laden with salty, saturated sediments. For MARSIS to be able to detect such a patch of water, it would need to be at least several tens of centimetres thick.

The data here is somewhat uncertain, but is also not to be dismissed. It is very likely this is liquid water.

I must add that this is not really a big surprise. Many scientists expected this. Also, this water is not very accessible, and is also located at the pole, the Mars’s harshest environment. Just because it is liquid is not a reason to aim to mine it. There is plenty of evidence of ice in much more accessible and reasonable locations.

What this discovery suggests is that it is possible to have liquid water on Mars. The great geological mystery of the planet is while that much of its geology appears formed by flowing water, scientists have not been able to devise good climate histories that make that flowing water possible. This discovery helps those scientists in devising those histories.

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The dust on Mars comes from one specific Martian region

9:39 am

Scientists have concluded that a large bulk of the dust that covers much of the Martian surface actually comes from one specific region called Medusae Fossae, located to the southwest of the planet’s giant volcanoes.

The dust that coats much of the surface of Mars originates largely from a single thousand-kilometer-long geological formation near the Red Planet’s equator, scientists have found.

A study published in the journal Nature Communications found a chemical match between dust in the Martian atmosphere and the surface feature, called the Medusae Fossae Formation. “Mars wouldn’t be nearly this dusty if it wasn’t for this one enormous deposit that is gradually eroding over time and polluting the planet, essentially,” said co-author Kevin Lewis, an assistant professor of Earth and planetary science at the Johns Hopkins University.

It is thought that Medusae Fossae is volcanic in origin.

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Radiation maps of Europa

10:08 am

By culling together data from Voyager 1 and the Galileo orbiter, scientists have created a radiation map of the surface of Europa.

Using data from Galileo’s flybys of Europa two decades ago and electron measurements from NASA’s Voyager 1 spacecraft, Nordheim and his team looked closely at the electrons blasting the moon’s surface. They found that the radiation doses vary by location. The harshest radiation is concentrated in zones around the equator, and the radiation lessens closer to the poles.

Mapped out, the harsh radiation zones appear as oval-shaped regions, connected at the narrow ends, that cover more than half of the moon.

…In his new paper, Nordheim didn’t stop with a two-dimensional map. He went deeper, gauging how far below the surface the radiation penetrates, and building 3D models of the most intense radiation on Europa. The results tell us how deep scientists need to dig or drill, during a potential future Europa lander mission, to find any biosignatures that might be preserved.

The answer varies, from 4 to 8 inches (10 to 20 centimeters) in the highest-radiation zones – down to less than 0.4 inches (1 centimeter) deep in regions of Europa at middle- and high-latitudes, toward the moon’s poles.

This model, which by the way probably has large margins of error, will be used as a guide by the Europa Clipper scientists now planning that orbiter’s mission.

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A dark dust avalanche on Mars

10:01 am

No dust avalanche

After dust avalanche

Cool image time! The two images to the right, both cropped to post here, were taken six years apart by Mars Reconnaissance Orbiter (MRO) of the western lava slopes of the giant volcano Olympus Mons. They show the appearance of a dark dust avalanche during the interim. As noted by members of the MRO science team.

Dust avalanches create slope streaks that expose darker materials usually hidden below a lighter-toned layer. Cascading fine-grained material easily diverts around boulders or alters direction when encountering a change in slope. The dark steak … is approximately 1 kilometer in length that we didn’t see in a previous image. Past avalanche sites are still visible and fading slowly as dust settles out of the atmosphere and is deposited on the dark streaks over time.

We also see boulders and their shadows that are a meter or greater in size. Movement of any of these boulders down the slope could trigger future avalanches.

The appearance of these Martian dark streaks on slopes is actually not uncommon. As more pictures are taken of Mars scientists are beginning to accumulate a large number all across the Martian surface.

What I find fascinating is the wet look of these dark streaks. Below is a close-up of the new avalanche, near its head.
» Read more

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Europe initiates website to name ExoMars 2020 rover

9:26 am

The European Space Agency has created a website where people can offer their suggestions to name the ExoMars 2020 rover.

Astronaut Tim Peake is leading the hunt for a great moniker. He wants everyone to go to a special website set up for the purpose and enter a suggestion. But don’t think “Spacey McSpaceFace” is a goer because this is not an online poll. All ideas will be put before an expert panel and it is they who will make the final choice.

If all goes right, 2020 should see two new rovers arrive on the Martian surface.

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