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Removing globally used anxiety drug from recycled and wastewater at low cost

Matter and energy from Science Daily Feed - Tue, 02/20/2018 - 7:24am
Researchers can now remove a common anxiety drug from recycled water and wastewater, using low-cost titanium dioxide nanofibers. In cities running out of water, removing pharmaceuticals from wastewater in a simple, low cost way is becoming a priority.
Categories: Science

When proteins shake hands

Matter and energy from Science Daily Feed - Tue, 02/20/2018 - 7:24am
Protein nanofibers often have outstanding properties such as a high stability, biodegradability, or antibacterial effect. Artificially creating these fibers is not easy, much less assigning them specific functions. That and how fibers with new properties can be successfully created is now being reported by materials scientists in a new study.
Categories: Science

Speech is not violence

Why Evolution is True Feed - Tue, 02/20/2018 - 7:00am

You may have heard that Ryan Spector, a Dartmouth student, got into big trouble for writing an op-ed in his college paper (The Dartmouth) questioning why 15 of the 19 directors of the student program “The Trips” (it runs summer excursions for incoming first-years) were female.  Claiming that this unbalanced sex ratio reflected an exercise in diversity gone wild, Spector got the response that selection was based purely on merit. He didn’t buy it, and concluded:

No matter how many men Trips excludes from directorate, the Class of 2022 will still be roughly 50 percent male. As they do each year, male members of the class will look for Trips role models who share their gender identity, just as any person might. But they will find fewer of them, because Trips is apparently no longer for trippees. It is for ideology, no matter how cruel the implications.

On a campus like Dartmouth (or pretty much any campus that isn’t religious), that’s stepping into a minefield, even if the selection was deliberately biased towards women. The claim that men needs “role models who share their gender identity” would be particularly inflammatory.  And opprobrium Spector got—in spades! As the conservative Dartmouth Review reported, noting that Spector’s piece was “inflammatory” and written “out of bitterness”

One day after the op-ed was posted, Link Up, a women’s student group, sent out a campus-wide email with the heading, “Statement in Solidarity”. The email defended Pierson and Rodriguez-Caspeta [the directors of Trips], and claimed that Spector’s article “attacks marginalized identities.” The email also celebrated the high percentage of female students in the new directorate as “correcting [for] years of underrepresentation and marginalization”.

. . . Throughout the weekend and into the next week, over 30 campus organizations followed their lead and sent out their own letters of “solidarity” with the Trips director and assistant director, further denouncing Spector’s op-ed as an “attack” on women and women of color. [JAC: There’s no mention of people of color in Spector’s article.] The wash of emails came from a wide range of student groups, including the Committee on Sexual Assault, several a capella groups, senior societies, sororities, one fraternity, and a variety of other minority and women’s groups. The emails varied in the severity of their accusations, but the allegations against Spector as a violent perpetrator of racism and sexism were common throughout.

. . . On Monday, a campus email from the Stonefence Review, a Dartmouth literary magazine, took a more personal turn. The letter first criticized Spector and called for The Dartmouth to rescind the op-ed, but then went on to publicly name the fraternity of which Spector is a member, demanding that the fraternity itself apologize for the “act of violence” that Spector committed. In bold font, the letter then calls on the fraternity to use their “place of power” with respect to Spector’s social life to “take a stand,” implying that the fraternity should take some sort of disciplinary action against him.

They conclude, and I agree, that this kind of vicious, personal, and bullying response was uncalled for. I wouldn’t have written what Spector did, but the kind of response he got reflects poorly on the offended.

FIRE (the Foundation for Individual Rights in Education), adds a bit more information and rebuts the oft-heard but erroneous claim that offensive speech is equivalent to physical violence:

As stated by one of Spector’s detractors when calling on Spector’s fraternity to condemn his op-ed: “[W]e call upon Alpha Chi Alpha to acknowledge that their own words do not recognize that their brother has committed an act of violence.”

Students are free to rebuke or ignore writing they find distasteful, and even call for social sanctions on the offending author. However, classifying political speech as literal violence has drastic consequences for those seeking to speak out on campus. Besides trivializing actual violence, conflating controversial opinions with physical harm justifies censorship and perhaps actual physical violence against the speaker in the name of supposed “self-defense” by aggrieved parties. It also sends the perverse message that college students are too weak to confront divergent ideas and must instead shield themselves from perceived “violent” viewpoints.

It’s time that we get this clear: speech, even “hate speech” is nothing like physical violence. The latter wounds bodies and is therefore illegal; the former may, at best, cause offense, and is Constitutionally legal. Further Spector may have had a point: perhaps there was selection bias towards females on that committee. If that was the case, then one needs to debate whether such a reverse gender bias is acceptable given years of bias against women. That’s the kind of discussion that, regardless of the outcome, moves society forward. Responding with names, hatred, and doxxing does not answer Spector’s claim, even if it was inflammatory.

Further, the “normalization” (I don’t like that word) of “hate speech” as “violence” is itself a recipe for real, physical violence. If you consider the sentiments of white supremacists—or the tamer words of Spector—as “violence”, you might be tempted to answer them with real violence, causing a brawl that hurts bodies and property. That, in fact, is exactly what happened at UC Berkeley when Milo Yiannopoulos spoke: Antifa and their minions went wild, doing thousands of dollars of damage to Berkeley storefronts. Yiannopoulos wasn’t silenced, except for the moment (he’s been in disgrace for other things he said).

If a criticism of biased sex ratios, and the implication of “reverse discrimination,” constitutes violence, then almost anything can be seen that way, launching not just the outpouring of hatred that Spector received (note that I don’t call that “violence”), and maybe even pitched battles—the kind of battle that Evergreen State students were seeking when they roamed the campus with baseball bats after the Bret Weinstein affair.

As FIRE concludes, “Free speech, properly understood, is not violence. It is a cure for violence.”

h/t; Grania

Categories: Science

Mystery honeycombs in rock may be created by water and salt

New Scientist Feed - Tue, 02/20/2018 - 7:00am
Many rocks are covered with circular hollows that look like honeycomb, and now we may finally understand how these strange formations come into existence
Categories: Science

Everyone should know by now that Twitter is a bad company

Pharyngula Feed - Tue, 02/20/2018 - 6:38am

From an inside look at Twitter’s problems with management, technology, and trolls:

At the same time, her defenders say, Harvey has been forced to clean up a mess that Twitter should have fixed years ago. Twitter’s backend was initially built on Ruby on Rails, a rudimentary web-application framework that made it nearly impossible to find a technical solution to the harassment problem. If Twitter’s co-founders had known what it would become, a third former executive told me, “you never would have built it on a Fisher-Price infrastructure.” Instead of building a product that could scale alongside the platform, former employees say, Twitter papered over its problems by hiring more moderators. “Because this is just an ass-backward tech company, let’s throw non-scalable, low-tech solutions on top of this low-tech, non-scalable problem.”

Calls to rethink that approach were ignored by senior executives, according to people familiar with the situation. “There was no real sense of urgency,” the former executive explained, pointing the finger at Harvey’s superiors, including current C.E.O. Jack Dorsey. “It’s a technology company with crappy technologists, a revolving door of product heads and C.E.O.s, and no real core of technological innovation. You had Del saying, ‘Trolls are going to be a problem. We will need a technological solution for this.’” But Twitter never developed a product sophisticated enough to automatically deal with with bots, spam, or abuse. “You had this unsophisticated human army with no real scalable platform to plug into. You fast forward, and it was like, ‘Hey, shouldn’t we just have basic rules in place where if the suggestion is to suspend an account of a verified person, there should be a process in place to have a flag for additional review, or something?’ You’d think it would take, like, one line of code to fix that problem. And the classic response is, ‘That’s on our product road map two quarters from now.’”

None of this means that Twitter is going to vanish soon — after all, COBOL is still around, and software legacies just hang around, decaying slowly, like an assortment of pseudogenes. But still, maybe you should consider jumping ship, since the one way to kill it is to erode its user base. Mastodon is out there, waiting for you with open arms.

Categories: Science

Fake news ‘vaccine’: online game may ‘inoculate’ by simulating propaganda tactics

Computers and Math from Science Daily Feed - Tue, 02/20/2018 - 6:35am
A new online game puts players in the shoes of an aspiring propagandist to give the public a taste of the techniques and motivations behind the spread of disinformation -- potentially 'inoculating' them against the influence of so-called fake news in the process.
Categories: Science

'Ultramassive' black holes discovered in far-off galaxies

Space and time from Science Daily Feed - Tue, 02/20/2018 - 6:32am
Thanks to data collected by NASA’s Chandra X-ray telescope on galaxies up to 3.5 billion light years away from Earth, an international team of astrophysicists was able to detect what is likely to be the most massive black holes ever discovered in the universe. The team’s calculations showed that these “ultramassive” black holes are growing faster than the stars in their respective galaxies.
Categories: Science

Technology firms must develop new ways to jam Russia’s fake news

New Scientist Feed - Tue, 02/20/2018 - 6:03am
The FBI has revealed the lengths Russia's fake news operators will go to – now the likes of Facebook and Twitter must come up with a fix, says Paul Marks
Categories: Science

Are computers better than people at predicting who will commit another crime?

Science News Feed - Tue, 02/20/2018 - 6:00am
If crime-predicting computer programs aren’t any more accurate than human guesswork, do they still have a place in the criminal justice system?
Categories: Science

So long, Sue…. see you upstairs!

Why Evolution is True Feed - Tue, 02/20/2018 - 5:45am

by Greg Mayer

Sue, the iconic Tyrannosaurus rex that has inhabited the Field Museum of Natural History‘s Stanley Field Hall since 2000, is coming down. But, shortly after she comes down, she’ll be going up– upstairs that is.  The Museum announced plans last year to replace Sue in Stanley Field Hall with a model of Patagotitan mayorum, a much larger dinosaur than Tyrannosaurus rex. At the same time, they’ll be adding plants and pterosaurs to the Hall. Bill Simpson (who for some reason appears to be being assisted by Ricky Gervais) explains what’s going to happen to her in this video. (And continue watching the next video, also featuring Bill, that comes up after the first finishes.)

A similar model of Patagotitan has been on display at the American Museum of Natural History in New York for a couple of years now. It doesn’t even fit in the dinosaur hall there, and its head and neck poke out into the hall way to greet visitors arriving by elevator! Sue will be moving upstairs to the Field’s second floor, whose balconies overlook the Hall, where she’ll join the rest of the dinosaurs in the Evolving Planet exhibit. Sue is a theropod, and though in the same order of dinosaurs as Patagotitan, which was a sauropod, Sue and her kin ate creatures like Patagotitan and its kin.

I had gotten to see Sue up close during the study and preparation phases prior to her being placed on exhibit, and wanted to say farewell (for a little while), so I went down to see her before the deconstruction. These are pictures from a visit in late December.

Sue towers over her human prey admirers in Stanley Field Hall.

Getting closer to Sue’s business end.

The better to eat you with.

The somewhat old-fashioned painted reconstruction on the second floor, overlooking Sue down below. Sue’s skull, which is too heavy to be supported on the body of the mounted skeleton in Stanley Field Hall, has always resided in a separate display case on the second floor balcony, just below this painting.

One of the pterosaurs is already in position.

I went down again last month, and took a few more pictures, mostly closer shots of interesting parts of her anatomy.

A closer view of her teeth.

Her reduced, two-fingered, forelimbs. The functional significance of this feature is much speculated on, but unknown.

Her strong, 4-toed (3 forward, 1 back) hind foot. These provided a powerful mode of locomotion.

Au revoir, Sue!

The tale of how Sue got from South Dakota to the Field Museum is a long and tortuous one, and not very edifying; but that’s a story for another post.

Categories: Science

Normalizing the intolerable

Pharyngula Feed - Tue, 02/20/2018 - 5:42am

Here is an article about the Virginia Tech shootings, over a decade ago. It’s remarkable how little has changed, how little has been done.

The cell phones in the pockets of the dead students were still ringing when we were told that it was wrong to ask why. As the police cleared the bodies from the Virginia Tech engineering building, the cell phones rang, in the eccentric varieties of ring tones, as parents kept trying to see if their children were O.K. To imagine the feelings of the police as they carried the bodies and heard the ringing is heartrending; to imagine the feelings of the parents who were calling—dread, desperate hope for a sudden answer and the bliss of reassurance, dawning grief—is unbearable. But the parents, and the rest of us, were told that it was not the right moment to ask how the shooting had happened—specifically, why an obviously disturbed student, with a history of mental illness, was able to buy guns whose essential purpose is to kill people—and why it happens over and over again in America. At a press conference, Virginia’s governor, Tim Kaine, said, “People who want to . . . make it their political hobby horse to ride, I’ve got nothing but loathing for them. . . . At this point, what it’s about is comforting family members . . . and helping this community heal. And so to those who want to try to make this into some little crusade, I say take that elsewhere.”

You remember Tim Kaine, right? Democrat? Failed vice presidential candidate? It’s not just Republicans with their heads in the sand. Guess what? I’ve got nothing but loathing for politicians who see their constituents murdered, and who do nothing but kowtow before the NRA. (Kaine does have an “F” rating from the NRA, which just shows how little resistance you have to exhibit to get dinged by those ghouls).

Here’s another dismaying story from 2016. A woman is in an abusive relationship; the guy is good looking and intelligent, but becomes progressively more possessive and controlling. It just gets worse and worse, but she’s in denial and tries to see the man she loves in this domineering, temperamental monster. The relationship doesn’t end until he shoots her in the face.

It’s a metaphor for America. We’re also in a terrible, abusive relationship, where any outsider looking in would say it’s obvious, you’ve got to break it up, you know this is bad for you, why are you tolerating this impossible, self-destructive affair? Get out! Get out now!

Only it’s worse, because in this metaphor, he shoots us in the face, and we don’t leave. He shoots us in the face again, we don’t leave. He shoots us in the face every few days, and we say, “This is not the time to dissolve our relationship, he just shot me in the face. I need time to heal!” And he shoots us again.

We’ve always got an excuse. It’s way past time that we stopped rationalizing this deadly relationship and ended it.

Categories: Science

How can you screw up an appeal to the alt-right?

Pharyngula Feed - Tue, 02/20/2018 - 5:12am

One of the dismaying things about the world right now is that being an alt-right/Nazi/”centrist” is so darned easy: they’re fanatically dominating YouTube*, they’re raking in the Patreon bucks, it’s almost as if mindlessly shouting “MAGA” and “WHITE GENOCIDE” is the magic cheat code for immense popularity. So when I see someone fail, it’s a bit jarring.

Look at Jon del Arroz, the leading Hispanic voice in science fiction, as he’s fond of claiming. He’s got the MAGA hat. He’s fond of Trumpian hyperbole and raging at liberals and SJWs. He got banned from WorldCon for his troubles, so he’s busy waving his martyr’s flag. And then he announced that he was going to sue WorldCon, and started a fundraiser to scrape up $10,000 for a lawyer.

He’s raised nothing. He’s a total failure. Maybe it’s because he compared his persecution to that of the entire gay community, which isn’t going to gather much sympathy from the usual gang of racist homophobes. Anyway, it’s nice to see a right-winger fall flat on his face.

*Since I’m trying to participate more in YouTube lately, I’m seeing signs that this may not be entirely true. I’ve encountered a few people who’ve been haranguing me with multiple sock puppets — one guy is up to about 20 pseudonyms — and I’m beginning to suspect that the right-wing success story on that medium is more about fanaticism, misrepresentation, and persistence. Maybe if YouTube were to tighten up their rules on handing out new accounts freely there’d be a change, because jeez, a lot of the problems in their comment threads are due to the deniability and meaninglessness of their contributors.

Categories: Science

Tuesday: Hili dialogue

Why Evolution is True Feed - Tue, 02/20/2018 - 4:45am

Good morning on Tuesday, February 20, predicted to be extraordinarily warm in Chicago, with a high of 58° F (14° C). It will also be pouring rain most of the day, as it is already. But all that will not only melt the snow, but wash the grime and salt off my car.  It’s also National Muffin Day, but I think I might have a donut instead. Finally, I don’t know how to say this, but it’s also the World Day for Social Justice.

Let’s begin with a tw**t that’s gone viral: a guy destroys his AR-15 and explains why:

ONE LESS: Scott Pappalardo owned his AR-15 rifle for more than 30 years. He even has a Second Amendment tattoo on his arm. This weekend, he destroyed his gun “to make sure this weapon will be ever be able to take a life.” https://t.co/M8nu4XyuZr pic.twitter.com/T6YGVxAYDR

— ABC News (@ABC) February 19, 2018

On February 20, 1472, Norway “pawned” Orkney and Shetland to Scotland in lieu of a dowry for Margaret of Denmark, who became Queen of Scotland. But if they were pawned, why do they still belong to the UK instead of Norway? Did Norway not turn in the pan ticket and get the islands back?

On this day in 1792, George Washington signed the Postal Service Act establishing the US Post Office, whose worst service is now in Chicago. On this day in 1816, Rossini’s opera “The Barber of Seville” had its premiere in Rome, and, in 1872, it was on this day that the Metropolitan Museum of Art opened in New York City. Another premiere: on February 20, 1877, Tchaikovsky’s ballet “Swan Lake” opened at the Bolshoi Theater in Moscow. On this day in 1935, Caroline Mikkelsen, a Danish/Norwegian explorer, became the first woman to set foot in Antarctica, though it’s not clear whether she landed on the continent itself or on an island. On this day in 1942, Lieutenant Edward “Butch” O’Hare became World’s War II’s first flying ace. He was shot down in 1943, and his plane was never found. O’Hare Airport in Chicago is, of course, named after him.

On this day in 1943, The Saturday Evening Post published the first  illustration of Norman Rockwell’s Four Freedoms (“Freedom of Speech”), following President Franklin Roosevelt’s 1941 State of the Union address, which had that theme. Six years ago, the Moving Naturalism Forward meeting was in Stockbridge, Massachusetts, home of Norman Rockwell, and I visited his studio and museum with Dan Dennett and Richard Dawkins. Here’s Richard standing in front of the original “Freedom of Speech” painting, which shows an ordinary guy speaking his mind at a New England town meeting.

On this day in 1962, a day I remember well, astronaut John Glenn became the first American to orbit the Earth, completing three orbits in his Friendship 7 capsule. It took about five hours. Finally, on this day 20 years ago, American figure skater Tara Lipinski became the youngest gold medalist at the Winter Olympics in Nagano, Japan. She was just 15 years old. You can see Lipinski today as one of NBC’s skating commentators for the Korean Olympics.

Notables born on November 20 include Ludwig Boltzmann (1844), Louis Kahn (1901), Ansel Adams (1902), Robert Altman (1925), Sidney Poitier (1927; 91 today), Buffy Sainte-Marie (1941), Walter Becker (1950; died last year), Gordon Brown (1951), Patty Hearst (1954), Cindy Crawford (1966), and Trevor Noah (1984).  Those who crossed the Rainbow Bridge on this day include William, Prince of Orange (1618), Frederick Douglass (1895), Robert Peary (1920), Gene Siskel (1999), Sandra Dee (2005), John Raitt (2005; actor, father of Bonnie), Hunter S. Thompson (2005), and Alexander Haig (2010).

Meanwhile in Dobrzyn, Hili is speculating idly. Malgorzata explains: On a walk Hili was observing with fascination workers dismantling a house.  Andrzej was fascinated with her fascination. That’s the origin of the dialogue.

 

Hili: What are they doing there? A: They are demolishing an old house. Hili: They will probably build something else.  In Polish: Hili: Co oni tam robią?
Ja: Burzą stary dom.
Hili: Pewnie będą coś budować.

Grania sent me this tw**t, and I thought it was fake news, but it’s not. You can find the full story here (or click on headline below the tweet).

I hereby illustrate the story of the escaped cow. pic.twitter.com/FOxXMXUrwr

— Alex Paterson (@Alexrjpaterson) February 18, 2018

From Matthew, who added this:

I think what’s going on here is in fact quite interesting – the pigeon has momentum, but also wants to keep control of the space it’s kicked its rival off. The only solution is to dissipate the momentum in a dramatic backward roll, then it can settle. Working all that out in its little brain, so quickly, is pretty damn smart.

Aerially superior pigeon dismisses its rival, performing a victory backward somersault; the soar loser flaps away in defeat. pic.twitter.com/4YV21tSlKW

— Dick King-Smith HQ (@DickKingSmith) February 18, 2018

Matthew sent this, too, calling it “recursive dog”. He thinks it’s real, but is it really Photoshopped? I’m thinking it’s real.

Just met this little chap on Sherwood Park he has a selfie on his ear pic.twitter.com/lgJ2HktQ9b

— The City Of Preston (@CityofPreston1) February 18, 2018

From Grania—A cat with its own pet:

When your cat has a pet of its own pic.twitter.com/l5Xgzgs94q

— HUMOROUS ANIMALS (@CUTEFUNNYANIMAL) February 15, 2018

And a lovely murmutation of starlings. Remember, nobody really knows why they do this:

Have a break, watch 40,000 starlings dancing around before they go to bed on the reeds at #Minsmere
For maybe 40 minutes on Saturday evening, this was the greatest show I’ve ever seen. Utterly, utterly breath-taking. @RSPBMinsmere @Natures_Voice @BBCSpringwatch #suffolk pic.twitter.com/gFaFKDqd7D

— Tom Griffiths (@TomGriffola) February 19, 2018

This black dog, named Paddy the Magnificent Hound, is owned by reader Tim Anderson. It is a black dog.

Categories: Science

I knew what that was as soon as I saw it

Pharyngula Feed - Tue, 02/20/2018 - 4:37am

Do you?

You’ll have to go elsewhere to find out if you don’t.

Categories: Science

The flowers that give us chocolate are ridiculously hard to pollinate

Science News Feed - Tue, 02/20/2018 - 4:00am
Cacao trees are really fussy about pollination.
Categories: Science

We all need to take our heads out of the sand

New Scientist Feed - Tue, 02/20/2018 - 1:00am
The fact we are running out of something so seemingly limitless as sand is a potent symbol of humanity's destructiveness. We must all strive to do better
Categories: Science

A Cornucopia of Crislip

Science-based Medicine Feed - Tue, 02/20/2018 - 12:00am
Mark Crislip has written three books. They are full of wisdom, science-based thinking, and hilarious humor. Highly recommended.
Categories: Science

Opportunity Just Saw its 5,000th Sunrise on Mars

Universe Today Feed - Mon, 02/19/2018 - 6:19pm

It’s been a time of milestones for Mars rovers lately! Last month (on January 26th, 2018), NASA announced that the Curiosity rover had spent a total of 2,000 days on Mars, which works out to 5 years, 5 months and 21 days. This was especially impressive considering that the rover was only intended to function on the Martian surface for 687 days (a little under two years).

But when it comes to longevity, nothing has the Opportunity rover beat! Unlike Curiosity, which relied on a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) for power, the solar-powered Opportunity recently witnessed its five-thousandth sunrise on Mars. This means that the rover has remained in continuous operation for 5000 sols, which works out to 5137.46 Earth days.

This five-thousandth sunrise began on Friday, Feb. 16th, 2018 – roughly 14 Earth years (and 7.48 Martian years) after the rover first landed. From its position on the western rim of the Endeavour Crater, the sunrise appeared over the basin’s eastern rim, about 22 km (14 mi) away. This location, one-third of the way down “Perseverance Valley”, is more than 45 km (28 mi) from Opportunity’s original landing site.

Mosaic view looking down from inside the upper end of “Perseverance Valley” on the inner slope of Endeavour Crater’s western rim. Credit: NASA/JPL/Cornell/Marco Di Lorenzo/Ken Kremer/kenkremer.com

This is especially impressive when you consider that the original science mission was only meant to last 90 sols (92.47 Earth days) and NASA did not expect the rover to survive its first Martian winter. And yet, the rover has not only survived all this time, it continues to send back scientific discoveries from the Red Planet. As John Callas, the Opportunity Project Manager at NASA’s Jet Propulsion Laboratory, explained in a NASA press release:

“Five thousand sols after the start of our 90-sol mission, this amazing rover is still showing us surprises on Mars… We’ve reached lots of milestones, and this is one more, but more important than the numbers are the exploration and the scientific discoveries.”

For instance, the rover has provided us with 225,000 images since its arrival, and revealed that ancient Mars was once home to extensive groundwater and surface water. Beginning in 2008, it began working its way across the  Endeavour Crater in order to get a glimpse deeper into Mars’ past. By 2011, it had reached the crater’s edge and confirmed that mineral-rich water once flowed through the area.

At present, researchers are using Opportunity to investigate the processes that shaped Perseverance Valley, an area that descends down the slope of the western rim of Endeavour Crater. Here too, Opportunity has learned some fascinating things about the Red Planet. For instance, the rover has conducted observations of possible “rock stripes” in the valley, which could be indicative of its valley’s origin.

Textured rows on the ground in this portion of “Perseverance Valley” are under investigation by NASA’s Mars Exploration Rover Opportunity. Credits: NASA/JPL-Caltech

These stripes are of interest to scientists because of the way they resemble rock stripes that appear on mountain slopes here on Earth, which are the result of repeated cycles of freezing and thawing on wet soil. On Mauna Kea, for example, soil freezes every night, but is often dry due to the extreme elevation. This causes soils that have high concentrations of silt, sand and gravel to expand, pushing the larger particles up.

These particles then form stripes as they fall downhill, or are moved by wind or rainwater, and cause the ground to expand less in this space. This process repeats itself over and over, creating a pattern that leads to distinct stripes. As Opportunity observed, there are slopes within the Perseverance Valley where soil and gravel particles appear to have formed into rows that run parallel to the slope, alternating between rows that have more and less gravel.

In the case of the Perseverance Valley’s stripes, scientists are not sure how they formed, but think they could be the result of water, wind, downhill transport, other processes, or a combination thereof. Another theory posits that features like these could be the result of changes in Mars tilt (obliquity) which happen over the course of hundreds of thousands of years.

During these periods, Mars’ axial tilt increases to the point where water frozen at the poles will vaporize and become deposited as snow or frost nearer to the equator. As Ray Arvidson, the Opportunity Deputy Principal Investigator at Washington University, explahttps://www.nasa.gov/feature/jpl/long-lived-mars-rover-opportunity-keeps-finding-surprisesined:

“One possible explanation of these stripes is that they are relics from a time of greater obliquity when snow packs on the rim seasonally melted enough to moisten the soil, and then freeze-thaw cycles organized the small rocks into stripes. Gravitational downhill movement may be diffusing them so they don’t look as crisp as when they were fresh.”

Stone stripes on the side of a volcanic cone on Mauna Kea, Hawaii, which are made of small rock fragments that are aligned downhill. These are formed when freeze-thaw cycles lift them out of the finer-grained regolith and move them to the sides, forming stone stripes. Credits: Washington University in St. Louis/NASA

Having the chance to investigate these features is therefore quite the treat for the Opportunity science team. “Perseverance Valley is a special place, like having a new mission again after all these years.” said Arvidson. “We already knew it was unlike any place any Mars rover has seen before, even if we don’t yet know how it formed, and now we’re seeing surfaces that look like stone stripes. It’s mysterious. It’s exciting. I think the set of observations we’ll get will enable us to understand it.”

Given the state of the Martian surface, it is a safe bet that wind is largely responsible for the rock stripes observed in Perseverance Valley. In this respect, they would be caused by sand blown uphill from the crater floor that sorts larger particles into rows parallel to the slope. As Robert Sullivan, an Opportunity science-team member of Cornell University, explained:

“Debris from relatively fresh impact craters is scattered over the surface of the area, complicating assessment of effects of wind. I don’t know what these stripes are, and I don’t think anyone else knows for sure what they are, so we’re entertaining multiple hypotheses and gathering more data to figure it out.”

Despite being in service for a little over 14 years, and suffering its share of setbacks, Opportunity is once again in a position to reveal things about Mars’ past and how it evolved to become what it is today. Never let it be said that an old rover can’t reveal new secrets! If there’s one thing Opportunity has proven during its long history of service on Mars, it is that the underdog can make some of the greatest contributions.

Further Reading: NASA, NASA (2)

The post Opportunity Just Saw its 5,000th Sunrise on Mars appeared first on Universe Today.

Categories: Science

Subscribe to Our New Weekly Email Newsletter Written By Fraser

Universe Today Feed - Mon, 02/19/2018 - 4:28pm

It’s been almost 19 years since I founded Universe Today, back in March, 1999.

Back when I started, it was a primarily an email-based newsletter with an archive version on the web where people could read it if they wanted to.

The technology was pretty rudimentary at the time, so I had to do everything by hand, sending out a BCC email to thousands of people every day, eventually finding other email mailing list providers. At some point, I shifted from commentary and summaries to full on reporting on space news. And at that time, automated tools arrived that would take all the stories you wrote in a day, bundled them up and sent them out via email to a list of subscribers.

That was great and convenient for me, but it didn’t make for the best experience. It lost its soul.

A couple of months ago, I decided to return to my roots and continue maintaining a weekly email newsletter that summarizes some of the top stories that happened this week. And not just stories from here on Universe Today, but stories from across the Universe of space journalists and websites, including Space.com, Ars Technica, Ethan Siegel, Brian Koberlein, TheVerge and many more. I see more amazing things out there than we could ever report on. I figured I might as well share it.

Each edition of the weekly newsletter comes out on Friday, and is hand-written personally by me, and includes a few dozen summaries and links to stories on Universe Today and beyond, as well as cool pictures, videos, and astrophotography.

Here’s an example of what it looks like.

It’s SPAM free, I won’t sell the email addresses to anyone. There aren’t any ads in them, although I’ll occasionally promote books, trips and other projects I’m working on, but tastefully, I promise.

And you can unsubscribe any time you like.

If that sounds good to you, go here and sign up.

The post Subscribe to Our New Weekly Email Newsletter Written By Fraser appeared first on Universe Today.

Categories: Science

The Dora Milaje had an actual historical inspiration

Pharyngula Feed - Mon, 02/19/2018 - 1:41pm

Women Soldiers of Dahomey (pdf)

It’s not exactly a pretty story, saturated as it is with slavery, colonialism and war, but it turns out that the Kingdom of Dahomey maintained an elite force of warrior women, the N’Nonmiton, in the 19th century. The comic book linked above tells their story, and these were definitely not put on for show — they were an active fighting force.

The Dahomey Warriors were known to be especially skillful, competitive, and brave. Their drills and military parades were always performed to dancing, music, and songs and their weapons were sometimes used as choreographic props. As expressed in their songs, their goal was to outshine men in every respect, and European travelers observed that they were better organized, swifter and much braver than male soldiers. As such, the King would send them to war as opposed to their male counterparts and European soldiers would also hesitate to kill them as they were often young women.

More details at the Smithsonian.

Categories: Science

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