"I hear the drizzle of the rain... Like a memory it falls..."
"I hear the drizzle of the rain... Like a memory it falls..."
The space agency said Wednesday that the Mars Reconnaissance Orbiter has sent back 100 terabits of information since 2006. That's equal to 100 trillion bits of data — the equivalent of about 3 million songs in MP3 format, or 35 hours of uncompressed high-definition video.
To put it another way, that's more than three times the total amount of data sent back by all the previous missions that have flown past the orbit of Earth's moon.
[. . .]
"What is most impressive about all these data is not the sheer quantity, but the quality of what they tell us about our neighbor planet," the orbiter's project scientist, Rich Zurek of NASA's Jet Propulsion Laboratory, said in a mission update. "The data from the orbiter's six instruments have given us a much deeper understanding of the diversity of environments on Mars today and how they have changed over time."
Among the mission's major achievements is the finding that water has had an effect on or near the surface of Mars for hundreds of millions of years. This activity was at least regional and possibly global in extent, though possibly intermittent.
The spacecraft has also observed signatures of a variety of watery environments, some acidic, some alkaline. Such observations increase the likelihood that future probes could find evidence of past life on Mars, if it ever existed.
This isn't nearly the volume of data I'd personally like, mind--I'd like more data, and preferably from more sources; it's a pity, I think, that the Voyager probes weren't joined in their Planetary Grand Tour of the four gas giants in sequence by others--but it's a good start.
A newly discovered star outside the Milky Way has yielded important clues about the evolution of our galaxy. Located in the dwarf galaxy Sculptor some 280,000 light-years away, the star has a chemical make-up similar to the Milky Way's oldest stars, supporting theories that our galaxy grew by absorbing dwarf galaxies and other galactic building blocks.
Some recent studies had questioned the link between dwarf galaxies and the Milky Way, citing differences between the chemistry of their stars. But the differences may not be so big after all, according to new research published in Nature. "It was a question of finding the right kind of star, and doing that required some new techniques," says Josh Simon , an astronomer at the Observatories of the Carnegie Institution and a member of team that confirmed the star's telltale chemistry. Using earlier techniques, he says, "it was very difficult to recognize exactly which stars were the key ones to study."
Dwarf galaxies are small galaxies with just a few million stars at most. They often orbit larger galaxies such as the Milky Way, which consists of hundreds of billions of stars. In the "bottom-up model" of galaxy formation, proposed in 1978 by Carnegie astronomers Leonard Searle and Robert Zinn (now at Yale University), large galaxies attained their size over billions of years by swallowing up their smaller neighbors. But if dwarf galaxies are the building blocks of larger galaxies, then the same kinds of stars should be found in both types of galaxies, especially in the case of old, "metal-poor" stars. (To astronomers, "metals" are chemical elements heavier than hydrogen and helium.) Because they are products of stellar evolution, metals were rare in the early Universe, and so old stars tend to be metal-poor.
Stars in the Milky Way's halo can be extremely metal-poor, with metal abundances as much as 100,000 times less than the Sun, which is an average metal-rich star. Surveys over the past decade had failed to turn up any such extremely metal-poor stars in dwarf galaxies. "The Milky Way seemed to have stars that were much more primitive than any of the stars in any of the dwarf galaxies," says Simon. "If dwarf galaxies were the original components of the Milky Way, then it's hard to understand why they wouldn't have similar stars."
Simon and his colleagues suspected that the methods used to find metal-poor stars in dwarf galaxies were biased in a way that caused the surveys to miss the most metal-poor stars. Team member Evan Kirby, a Caltech astronomer, developed a method to estimate the metal abundances of large numbers of stars at a time, making it possible to search efficiently for the most metal-poor stars in dwarf galaxies. Among stars he found in the Sculptor dwarf galaxy was one designated S1020549. Spectroscopic measurements of the star's light at Carnegie's Magellan-Clay telescope in Las Campanas, Chile, determined it to have a metal abundance more than 4,000 times lower than that of the Sun―five times lower than any other star found so far in a dwarf galaxy.
"This star is likely almost as old as the universe itself," said astronomer Anna Frebel of the Harvard-Smithsonian Center for Astrophysics, lead author of the Nature paper reporting the finding.
In addition to the star's total metal abundance, researchers also compared the abundance of iron to that of elements such as magnesium, calcium, and titanium. The ratios resembled those of old Milky Way stars, lending more support to the idea that these stars originally formed in dwarf galaxies.
As Will Baird noted last month at his blog, S1020549 might very well be the first of the ancient and oft-theorized Population III Stars to be discovered by astronomers.
Over the course of those jobs where I directly interacted with members of the public, I was hung up on and had doors slammed in my face. I was called as many nasty names as you can think of. (Motherfucker? Sure. Cunt? More times than I can count. Asshole? That was some people’s way of saying hello.) I cleaned vomit off upholstery and feces off bathroom floors. I fished dirty needles out of toilets. I was spit on. I was asked if I could “help a brother out” with a free meal or a coffee two or three times an hour while I worked in one café. I was threatened with a knife and with a bat. I had money stolen from me. On many, many occasions I had to chase customers down the street when they left without paying. (Their bill would be deducted from my wages if I didn’t catch them.) I was punched in the face more than once. I had my almost-new designer glasses (which cost me two weeks’ pay at the time) ripped off my face and crushed on the ground while one of my eyes was gouged by a particularly unstable and apparently homeless woman. And most of those things weren’t particularly notable parts of my workday when they happened. They came with the customer-service territory.
So, I think I can sympathize with the workplace hassles expressed by Alex C., the TTC bus driver who wrote a letter to the editor we published last week to complain that riders on our transit system are often ungrateful, slovenly brutes. Sympathize yes. Agree no. Because Mr. C seems to draw the conclusion that riders are the problem, and that the craptacular customer experience offered too often by the TTC is somehow the responsibility of riders, and that fixing it should be their responsibility too.
His attitude in this regard — which echoes to some extent the message often repeated by the Amalgamated Transit Union, which represents TTC employees — shows exactly how deeply ingrained the TTC’s customer service problems are into the mindset of the employees. The customer is the problem? No. The customer is the reason you have a job, and the reason the entire transit system exists. And some customers are not good customers, but they come with the territory. The job of the TTC as an organization is to ensure that those bad customers do not spoil everyone else’s experience.
[. . .]
Dealing with problem customers is an important element of any customer-service industry, but the primary objective there is to ensure that your problem customers do not bother your good customers. After I had my glasses smashed and my eye gouged and I managed to get the crazy woman out of the restaurant (with the help of the police), I spent 10 minutes apologizing personally to the other customers and giving them all a free drink. Why? It wasn’t my fault the crazy lady went apeshit on me, right? But it wasn’t the other customers’ fault either, and it was very unpleasant for them too. And I was being paid to be there, while they were actually paying for the privilege. And what’s more, I wanted them all to come back.
The reason you don’t see ads on restaurant walls asking people not to skip out on their bills or spit on their server or crap on the floor is twofold: first, the people who do those things won’t heed the signs. Second, the people who would never do those things find being reminded of such behaviour revolting, and resent the implication they need to be reminded to behave like human beings. And yet, the TTC runs ads reminding people that assaulting a driver is illegal.
To refer specifically to Alex C.’s letter again for a moment: he complains that customers litter the bus, and points out that each bus is cleaned before it goes into service for the day. To which the appropriate response is: buses are only cleaned of litter once a day? No wonder they’re such a mess. (Well, that and the fact that there are no garbage receptacles on the bus.) It may surprise Alex C. to learn that restaurants clean tables after every single customer — and wash the dishes and cutlery after every single customer too. It may surprise him more to learn that the New York transit system washes graffiti off of subway cars every single time they reach the end of the line. See, it’s not that customers in other businesses are cleaner than TTC riders, it’s that the people running other businesses think it’s part of the staff’s job to clean up after them.
Geologists working in the Canadian North have found evidence that the Earth's oceans were covered in ice all the way to the tropics more than 700 million years ago.
The researchers' findings give strength to the "snowball Earth" idea, that the planet was virtually covered in ice around the same time the first animals evolved.
The American and Canadian geologists analyzed rocks from the Yukon and Northwest Territories and found glacial deposits 716.5 million years old, based on precision uranium dating techniques.
The purplish glacial deposits were found on top of old reef material composed of carbonate, shifted north by the movement of tectonic plates.
The magnetic and chemical composition of the rocks indicate that they were located at sea level in the tropics — about 10 degrees latitude — when the deposits took place.
The study published this week in Science is the first evidence, the geologists say, that this glacier, called the Sturtian glaciation, reached the tropical latitudes.
Francis Macdonald of Harvard University, the study's lead author, said that the research provides "direct evidence that this particular glaciation was a 'snowball Earth' event."
"Our data also suggests that the Sturtian glaciation lasted a minimum of five million years," said Macdonald, in a statement.
Other evidence, from fossils and mineral isotopes, suggests the Sturtian glaciation could have lasted as long as 20 million years, from 720 million to 700 million years ago.
Geologists don't know what caused the Earth to freeze over or what ended the glacier event.
Fossils also show that early complex life forms, called eukaryotes, emerged before the Earth froze over and somehow survived the glaciation.
"The fossil record suggests that all of the major eukaryotic groups, with the possible exception of animals, existed before the Sturtian glaciation," Macdonald said.
A panel of 41 scientists from across the world reviewed 20 years' worth of research to try to confirm the cause of the so-called Cretaceous-Tertiary (KT) extinction, which created a "hellish environment" around 65 million years ago and wiped out more than half of all species on the planet.
Scientific opinion was split over whether the extinction was caused by an asteroid or by volcanic activity in the Deccan Traps in what is now India, where there were a series of super volcanic eruptions that lasted around 1.5 million years.
The new study, conducted by scientists from Europe, the United States, Mexico, Canada and Japan and published in the journal Science, found that a 15-kilometre (9 miles) wide asteroid slamming into Earth at Chicxulub in what is now Mexico was the culprit.
"We now have great confidence that an asteroid was the cause of the KT extinction. This triggered large-scale fires, earthquakes measuring more than 10 on the Richter scale, and continental landslides, which created tsunamis," said Joanna Morgan of Imperial College London, a co-author of the review.
The asteroid is thought to have hit Earth with a force a billion times more powerful than the atomic bomb at Hiroshima.
Morgan said the "final nail in the coffin for the dinosaurs" came when blasted material flew into the atmosphere, shrouding the planet in darkness, causing a global winter and "killing off many species that couldn't adapt to this hellish environment."
Scientists working on the study analyzed the work of paleontologists, geochemists, climate modelers, geophysicists and sedimentologists who have been collecting evidence about the KT extinction over the last 20 years.
Geological records show the event that triggered the dinosaurs' demise rapidly destroyed marine and land ecosystems, they said, and the asteroid hit "is the only plausible explanation for this."
Peter Schulte of the University of Erlangen in Germany, a lead author on the study, said fossil records clearly show a mass extinction about 65.5 million years ago -- a time now known as the K-Pg boundary.
Despite evidence of active volcanism in India, marine and land ecosystems only showed minor changes in the 500,000 years before the K-Pg boundary, suggesting the extinction did not come earlier and was not prompted by eruptions.
This website shows, with the help of Google Earth, just what the devastation would have looked like (earthquakes out to here, tsunamis to there ...)
In August we reported on a study that noted methane bubbling up from the seafloor near islands north of Norway, giving scientists a scare. This week in Science, another team reports seeing the same thing during thousands of observations of the East Siberian Arctic Shelf on Russia’s north coast, which is even more worrisome because it’s a huge methane deposit.
The shelf, which covers about 800,00 square miles, was exposed during the last ice age. When the region was above sea level, tundra vegetation pulled carbon dioxide from the air as plants grew. That organic material, much of which didn’t decompose in the frigid Arctic, accumulated in the soil and is the source of modern methane [Science News]. Now underwater, it’s covered by a layer of permafrost. But that permafrost seems to be becoming unstable, thanks to the fact that the water on top of it is warmer than the air it was exposed to back when it was on dry land.
The study said about 8 million tonnes of methane a year, equivalent to the annual total previously estimated from all of the world’s oceans, were seeping from vast stores long trapped under permafrost [Reuters]. Study leader Natalia Shakhova says methane levels in the Arctic haven’t been this high in 400,000 years. While we’re not about to teeter off a cliff—that 8 million tons is a small portion of the global emissions of 440 million tons—we should be concerned, the scientists say. Methane is a far more powerful greenhouse gas than carbon dioxide, absorbing at least 25 times more heat, NOAA says.
It is possible that climate change could be contributing to the release, with warmer seas causing more methane to come out, creating a feedback loop. But methane has long been leaking, and there’s no record of the previous levels with which to verify how much methane emissions are increasing, or whether people are playing a part. While Shakhova says the warmer runoff into the Arctic ocean is probably contributing, the team can’t say that for sure.
What they can say for sure is that the methane levels there are extremely high. Most undersea methane oxidizes into CO2 as it enters the atmosphere, but Shakhova says the East Siberian Ice Shelf methane is too close to the surface for that to happen. As a result, she said, atmospheric levels of methane over the Arctic are 1.85 parts per million, almost three times as high as the global average of 0.6 or 0.7 parts per million. Concentrations over the shelf are 2 parts per million or higher [The New York Times]
In the poll, 59 percent say they now support allowing "homosexuals" to serve in the U.S. military, including 34 percent who say they strongly favor that. Ten percent say they somewhat oppose it and 19 percent say they strongly oppose it.
But the numbers differ when the question is changed to whether Americans support "gay men and lesbians" serving in the military. When the question is asked that way, 70 percent of Americans say they support gay men and lesbians serving in the military, including 19 percent who say they somewhat favor it. Seven percent somewhat oppose it, and 12 percent strongly oppose it.
When it comes to whether Americans support allowing gays to serve openly, there is also a difference based on the term used. When referred to as "homosexuals," 44 percent favor allowing them to serve openly. When referred to as "gay men and lesbians," the percentage rises to 58 percent.
Marginal Revolution picked this up independently, and some of the commenters there went on to make their own conclusions. Wagster, for instance, pointed out the subjectivity of language.
It's important to understand why the response changes. The respondent doesn't like gay men and lesbians more than homosexuals, but he/she is speaking to a stranger over the phone about a volatile subject. If the interviewer uses words gay people use to self-identify, then the respondent -- in order to not offend -- will respond favorably. If the interviewer uses the words that gay rights opponents use, again the respondent will attempt to not offend, and bend with the direction the interviewer is signaling.
I used to be a phone interviewer in college. Actually doing the interviews yourself makes you take them with a rather larger grain of salt when you read about them.
Albatross went on to argue that the term "homosexual" isn't closely associated in most people's minds with actual people, therein the problem.
Somehow, this makes me think of the common mental bias in which you think something is more likely because I give you a more vivid description. Homosexuals sounds kind of generic, and you don't automatically have a mental picture. Gay men and lesbians gives you more of a picture--it makes the question less about a category of faceless people, and more about people you can visualize. I suspect that this effect has to do with making the question more personal, or more about a story the person responding to can visualize, and less about abstract questions of rights or laws.
Is there a term for this kind of bias w.r.t. empathy? You can give me infant mortality and malnutrition statistics for Bangladesh, or you can show me a picture of a starving Bangladeshi child, and I'm pretty sure #2 is more likely to get me to donate money.
(Me, I think of "gay" or "queer" as applying to people and to movements, and "homosexual" as being more than faintly medical and often subjected to pejorative uses by homophobes.)
Picking the right rhetoric for a campaign, any campaign, obviously matters, and the terms "gay" and "lesbian" are the words that people seem most ready to handle. Does anyone think that this is sophistry?