Slashdot Mirror

"The Register has an article on the possibility that a supernova or a series of them could explain a mass die-off of marine animals around 2.6 million years ago," writes Slashdot reader KindMind. From the report: A gigantic supernova explosion may have triggered mass extinctions for creatures living in Earth's prehistoric oceans some 2.6 million years ago, according to new research published in Astrobiology. Marine animals like the megalodon [...] suddenly disappeared during the late Pliocene. Around the same time, scientists [...] noticed a peak in the iron-60 isotope in ancient seabeds. "As far back as the mid-1990s, people said, "Hey, look for iron-60. It's a telltale because there's no other way for it to get to Earth but from a supernova.' Because iron-60 is radioactive, if it was formed with the Earth it would be long gone by now. So, it had to have been rained down on us" explained Adrian Melott, lead author of the paper and a physics and astronomy professor at the University of Kansas.

The team believes that a supernova located 150 light years away set of a chain of supernovae bursts and covered the Earth in a shroud of deadly cosmic ray radiation. This was amplified, Melott said, because the Solar System is right on the edge of an area of the interstellar medium called the Local Bubble. The Local Bubble extends about 300 light years across and contains the two main clouds of dust and gas: Local Interstellar Cloud and the G-Cloud. As the supernovae ejected cosmic rays, these beams of energetic particles would have repeatedly bounced off the clouds to create a "cosmic-ray bath" that could have lasted 10,000 to 100,000 years. Some of that radiation such as cosmic ray muons would have leaked onto Earth, and over time it could have led to genetic mutations and cancers [that would have caused animals like the megalodon to die off prematurely].

Scientists from Birkbeck, University of London speculate that recent results show that the moon is wetter than scientists have previously thought, increasing the possibility for it to have the necessary conditions for life. "Whether life ever arose on the Moon, or was transported to it from elsewhere, is of course highly speculative and can only be addressed by an aggressive future program of lunar exploration," they write in the article, published in the journal Astrobiology. Gizmodo summarizes: This habitability period, if it really occurred, might have happened either just after the Moon's formation from a massive collision with Earth 4.5 billion years ago, or 3.5 billion years ago, after a period of volcanism which may have resulted in a thin lunar atmosphere. Such an atmosphere would have lasted perhaps tens of millions of years. Maybe water existed on the Moon at this point. Maybe 10 million years was enough time for some rudimentary life to evolve on the Moon. Maybe Earthly life traveled over to the Moon on asteroids. Who knows.

The researchers stress that "habitability requires much more than just the presence of a significant atmosphere and liquid water." One such requirement would be the presence of organic compounds. And there are obviously not the same water-created features on the Moon that we see here on Earth or on Mars, like drainage channels -- though maybe these existed and were eroded by small meteors and solar winds. While the paper doesn't present new data, it's an interesting synthesis of lots of existing research demonstrating that, since the Moon is wetter than was initially thought, maybe it's worth wondering whether it was once habitable.

According to a new paper from Oxford Internet Institute researchers Victoria Nash and Andrew Przybylski, internet filters rarely work to keep adolescents away from online porn. Basically, the filters are expensive and they don't work. "Internet filtering tools are expensive to develop and maintain, and can easily 'underblock' due to the constant development of new ways of sharing content. Additionally, there are concerns about human rights violations -- filtering can lead to 'overblocking', where young people are not able to access legitimate health and relationship information." TechCrunch reports: The researchers "found that Internet filtering tools are ineffective and in most cases [and] were an insignificant factor in whether young people had seen explicit sexual content." The study's most interesting finding was that between 17 and 77 households "would need to use Internet filtering tools in order to prevent a single young person from accessing sexual content" and even then a filter "showed no statistically or practically significant protective effects." The study looked at 9,352 male and 9,357 female subjects from the EU and the UK and found that almost 50 percent of the subjects had some sort of Internet filter at home. Regardless of the filters installed, subjects still saw approximately the same amount of porn.

An anonymous reader quotes a report from Phys.Org: Rakesh Mogul, a Cal Poly Pomona professor of biological chemistry, was the lead author of an article in the journal Astrobiology that offers the first biochemical evidence explaining the reason the contamination persists. To figure out how the spacecraft microbiome survives in the cleanroom facilities, the research team analyzed several Acinetobacter strains that were originally isolated from the Mars Odyssey and Phoenix spacecraft facilities. They found that under very nutrient-restricted conditions, most of the tested strains grew on and biodegraded the cleaning agents used during spacecraft assembly. The work showed that cultures grew on ethyl alcohol as a sole carbon source while displaying reasonable tolerances towards oxidative stress. This is important since oxidative stress is associated with desiccating and high radiation environments similar to Mars. The tested strains were also able to biodegrade isopropyl alcohol and Kleenol 30, two other cleaning agents commonly used, with these products potentially serving as energy sources for the microbiome.

Elon Musk has put his Mars-colonization vision to paper, and you can read it for free. SpaceX's billionaire founder and CEO published the plan, which he unveiled at a conference in Mexico in September 2016, in the journal New Space. From a report: The paper outlines early designs of the gigantic spacecraft, designed to carry 100 passengers, that he hopes to construct. "The thrust level is enormous," the paper states. "We are talking about a lift-off thrust of 13,000 tons, so it will be quite tectonic when it takes off." Creating a fully self-sustained civilisation of around one million people -- the ultimate goal -- would take 40-100 years according to the plans. Before full colonisation takes place, though, Musk needs to entice the first pioneers to pave the way.

An anonymous reader writes: An equation, which calculates the probability of the evolution of other technological civilizations, has found that it's wildly unlikely we're the only time advanced society in the universe. Adam Frank from the University of Rochester and Woodruff Sullivan from the University of Washington base their new equation on the Drake equation, used for calculating the probability of extraterrestrial civilisation, written by astronomer and astrophysicist Frank Drake in 1961. The scientists also take into account Kepler, which suggests that one in five stars have planets in the habitable zone. Frank and Sullivan calculated that human civilisation is only unique if the odds of a civilisation developing on a habitable planet are less than one in 10 billion trillion. "One in 10 billion trillion is incredibly small. To me, this implies that other intelligent, technology producing species very likely have evolved before us," Frank said. Frank said: "Of course, we have no idea how likely it is that an intelligent technological species will evolve on a given habitable planet. But using our method we can tell exactly how low that probability would have to be for us to be the ONLY civilization the Universe has produced. We call that the pessimism line. If the actual probability is greater than the pessimism line, then a technological species and civilization has likely happened before."

An anonymous reader writes: MIT's Mediated Matter Group has published a paper and a video about their new technique for 3D printing with glass. The top part of their printer is a kiln that heats the glass to temperatures of approximately 1900 degrees Fahrenheit, causing it to melt. The molten glass is then passed through an alumina-zircon-silica nozzle, which moves just like an extruder on normal 3D printers. "The frame of the printer is constructed out of 80/20 aluminum stock and square steel tube. They used three independent stepper motors and a lead screw gantry system and drivers which were controlled via an Arduino and a RAMPS 1.4 Arduino shield." The device's makers say, "The tunability enabled by geometrical and optical variation driven by form, transparency and color variation can drive; limit or control light transmission, reflection and refraction, and therefore carries significant implications for all things glass."

An anonymous reader writes: Life as we know it requires small, rocky planets. The gas giants of our solar system aren't habitable (to our knowledge), but a research team has discovered that smaller, Neptune-like planets can be transformed into gas-free, potentially habitable worlds with a little help from red dwarf stars. Such planets are usually formed far out in a planetary system, but tidal forces can cause them to migrate inward. When they reach the habitable zone of their host star, they absorb far larger amounts of x-ray and ultraviolet radiation. This can eventually boil off most of the the gas atmosphere, leaving behind the core: a small, rocky world capable of supporting life.

An anonymous reader writes New research at the University of East Anglia finds that oceans are vital in the search for alien life. So far, computer simulations of habitable climates on other planets have focused on their atmospheres. But oceans play an equally vital role in moderating climates on planets and bringing stability to the climate, according to the study. From the press release: "The research team from UEA's schools of Mathematics and Environmental Sciences created a computer simulated pattern of ocean circulation on a hypothetical ocean-covered Earth-like planet. They looked at how different planetary rotation rates would impact heat transport with the presence of oceans taken into account. Prof David Stevens from UEA's school of Mathematics said: 'The number of planets being discovered outside our solar system is rapidly increasing. This research will help answer whether or not these planets could sustain alien life. We know that many planets are completely uninhabitable because they are either too close or too far from their sun. A planet's habitable zone is based on its distance from the sun and temperatures at which it is possible for the planet to have liquid water. But until now, most habitability models have neglected the impact of oceans on climate.'"

An anonymous reader writes "Scientists at NASA and JPL have found evidence of past water movement throughout a Martian meteorite, reviving debate over life on Mars. 'In this new study, Gibson and his colleagues focused on structures deep within a 30-pound (13.7-kilogram) Martian meteorite known as Yamato 000593 (Y000593). The team reports that newly discovered different structures and compositional features within the larger Yamato meteorite suggest biological processes might have been at work on Mars hundreds of millions of years ago. ... Analyses found that the rock was formed about 1.3 billion years ago from a lava flow on Mars. Around 12 million years ago, an impact occurred on Mars which ejected the meteorite from the surface of Mars. The meteorite traveled through space until it fell in Antarctica about 50,000 years ago.'"

cold fjord writes "The Independent reports, 'Being pulled into the world of a gripping novel can trigger actual, measurable changes in the brain that linger for at least five days after reading ... The new research, carried out at Emory University ... found that reading a good book may cause heightened connectivity in the brain and neurological changes that persist in a similar way to muscle memory. The changes were registered in the left temporal cortex, an area of the brain associated with receptivity for language, as well as the primary sensory motor region of the brain. Neurons of this region have been associated with tricking the mind into thinking it is doing something it is not, a phenomenon known as grounded cognition — for example, just thinking about running, can activate the neurons associated with the physical act of running. "The neural changes that we found associated with physical sensation and movement systems suggest that reading a novel can transport you into the body of the protagonist," said neuroscientist Professor Gregory Berns, lead author of the study. "We already knew that good stories can put you in someone else's shoes in a figurative sense. Now we're seeing that something may also be happening biologically."'"

astroengine writes "Europa has only been seen from afar, but its aura of intrigue has inspired scientists to study ideas as to how to explore the icy Jovian moon. In a new study published in the journal Astrobiology [paper], a NASA-appointed science definition team lays out the rich tapestry of discovery facing any mission to study Europa, but what questions do we need answering? 'If one day humans send a robotic lander to the surface of Europa, we need to know what to look for and what tools it should carry,' said Robert Pappalardo, of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the study's lead author. 'There is still a lot of preparation that is needed before we could land on Europa, but studies like these will help us focus on the technologies required to get us there, and on the data needed to help us scout out possible landing locations. Europa is the most likely place in our solar system beyond Earth to have life today, and a landed mission would be the best way to search for signs of life.'"

pigrabbitbear writes "A new study (abstract) from Michigan State University shows that media multitasking exhibits a strong correlation with social anxiety and depression. Importantly, the direction of causality remains to be seen: Does multi-tasking make us more anxious and depressed? Or, as the study's leader, Mark W. Becker, an assistant professor of psychology, put it in an email, 'are depressed and anxious [people] turning toward media multitasking as a form of distraction?' The results of this study aren't conclusive in that regard, he says. But they're an important step. 'While that question will not be easy to answer, it is worth pursing because the practical implications of the findings depend on the causal direction,' he said."

duh P3rf3ss3r writes "The BBC is carrying a report from a team of researchers at Newcastle University who claim to have developed a the first 'artificial' human sperm from stem cells. The research, reported in the journal Stem Cells and Development, involved selecting meristematic germ cells from a human embryonic stem cell culture and inducing meiosis, thus producing a haploid gamete. The authors claim that the resulting sperm are fully formed, mature, human sperm cells but the announcement has been greeted with mixed reaction from colleagues who claim the procedure is ethically questionable and that the gametes produced are of inferior levels of maturation."

stemceller brings us a story about an experiment that was published online in the journal Cloning & Stem Cells. The paper demonstrated that embryonic stem cells can be used to develop therapeutic cells which will not provoke an immune response from a significant portion of the population. This comes alongside news that UC Irvine researchers have found a method of sorting stem cells that should be "quicker, easier and more cost-effective than current methods." The Cloning & Stem Cells publication states: "It is likely that treatment of large numbers of patients by cell therapy will only be possible if methods are found using any one cell line to treat very large numbers of patients. This very exciting paper represents a significant step forward towards the use of such cells in cell therapy."