Science at Atheist Universe
VIDEO THE WEEK: Temporal Distortion: Halverson, who recently won a time-lapse video competition with one of his Milky Way clips, photographed this sequence during the summer and fall of 2011 in South Dakota, Utah and Colorado. "What you see is real, but you can't see it this way with the naked eye. It is the result of 20-30 second exposures, edited together over many hours to produce the time-lapse," Halverson wrote. At 0:53 and again at 2:17, for example, meteors with persistent trails twinkle into view.
More videos in the Comment section of The Daily Cosmos.
Valentine’s Day was this past Tuesday, and naturally we had to discuss love from a scientific point of view:
NEUROSCIENCE: The neuroscience of love. It's Valentine's Day, how is your brain activity today, when you think of the one (or ones) you love? Would an fMRI of your brain show that you love a person more intensely than others are capable of loving? Check out this 15-minute film by Brent Hoff, in collaboration with Stanford University neuroscientists, "The Love Competition". The brain activity of seven test subjects ("contestants") was measured by fMRI while they were thinking about the one they love, thinking about loving that person, as hard as they could, for 5 minutes. By fMRI, they measured activity in regions known to produce the neurochemicals of love: oxytocin/vasopressin, serotonin, dopamine. Based on this activity, it was possible for the scientists doing the neuroimaging to tell who loved the most intensely. The participants reported feeling giddy or even very moved while they were thinking of the love of their lives. Interestingly, the happiest person is the guy who came in last, because he felt he has confirmation that he really didn't love his girlfriend. Check out the 10 year old boy (adorable). But it's interesting that the neuroscientist predicted the winner would be an older person.
ANTHROPOLOGY: The cultural roots of human evolution. Do not miss this fascinating article about human culture and paleoclimate. It describes the work of South African archaeologist Chris Henshilwood, and the Blombos Cave excavations. The cave has yielded remains of ancient feasts, charred animal bones left behind, over thousands of years of humans visiting the cave. Seventy eight thousand (78,000!) years ago, there were anatomically modern humans in that area of South Africa, and they were one of the most advanced Middle Stone Age groups. It is now known as the Still Bay culture. They had distinctive tools and decorated rocks with symbolic designs. But 71,000 years ago, this culture disappeared. It took 7,000 years for another culture (the Howiesons Poort culture, which appeared 65,000 years ago and persisted for about 5,000 years), to replace them.. But what caused the disappearance of the still Bay culture. Henshilwood thinks that climate change was one reason: the planet was cooling further and the seas retracted right around the time of the culture’s demise. Modern genetic analysis confirms that at around that time, our genetic pool contracted, because the population decreased. It later rebounded and expanded further into Africa and ultimately, throughout the globe. Read the Nature article that is linked into the discussion for a riveting account of Henshilwood’s career and discoveries, including his latest discovery of shells, and stones used to process and store ochre, presumably used as decorative pigment or for tanning hides or cleaning wounds. That is evidence of sophisticated human behavior and it was such a long time ago! I cannot even imagine 78,000 years ago. I can understand time rationally, but emotionally, it is not automatic. Ultimately, these archaeologists want to determine the role of ecology and the environment in determining the type of human culture developed. They are currently collecting data to determine the paleoclimate of each area and then they will overlay the climate and cultural data onto an ecological model, and analyze the environmental space in relation to the specific local cultures, throughout time. One of the questions they aim to answer is whether similar cultures occupy similar landscapes or respond to climatic shifts in similar ways.
Two fascinating findings in the ZOOLOGY: New species of minuscule chameleon: an extreme example of island dwarfism. It seems almost impossible that an amniote (group comprising the reptiles, birds and mammals, with eggs adapted to terrestrial living, endowed with protective membranes) can get so small. It is no surprise that these tiny chameleons are found in an island, since evolutionary biology has shown that many animals have evolved into miniaturized forms as a consequence of living in a small environment (insular dwarfism). A recent PLoS One publication describes four new species of tiny leaf chameleons, belonging to the genius Brookesia, in Northern Madagascar. Madagascar is already famous for its high levels of species diversity and species that are exclusive to the island. It seems to be a constant source of discovery of new species, especially reptiles and amphibians. Several species of dwarf frogs and dwarf chameleons endemic to Madagascar have been described already. One of these new species (Brookesia micra) measures 29 mm from snout to tip of the tails! It is one of the smallest reptiles in the world. It is possible that its extreme miniaturization is due to a "double island" effect since B. micra is found exclusively in a small islet off the coast of the island. Even more remarkably, these 4 tiny species are genetically distant, even if they superficially they look pretty similar. They have been separated by millions of years of separate evolution, and they all live within very small ranges of a few square miles.
Piranha-proof scales. The voracity and sharp teeth of the piranha are legendary. I had no idea that there was anything the piranha could not eat. But there is a fish, a relic of evolution, the arapaima (Arapaima gigas), an 8-to-10-foot long "living fossil" fish with lungs, that actually breathes air through its mouth. The arapaima, also called pirarucu or paiche, has almost been fished to extinction because of its almost boneless, succulent flesh. It is now protected and can only be fished by native tribes of the Amazon for their own sustenance. Fishermen had observed arapaima swimming in a swarm of piranhas in a feeding frenzy, quickly dispatching bait, and had noticed that the arapaima is simply not attacked. Why? Researchers have now shown that the arapaima's scales cannot be penetrated by piranha's teeth, they actually shatter piranha's teeth, when attached to a machine designed to deliver a piranha bite. It's not just the large size of the arapaima's scales that make it resistant to piranha's teeth. The scales are actually two-layered. Using a scanning electron microscope, the researcher showed that on the inside, they are made of collagen, but on the outside, they are made of collagen fibers strengthened by calcium. The double-layered nature makes the scales super-resistant, because even if the calcium-hard outside is cracked, the pliable collage inside cushions the bite and stops the cracks from propagating. As a result, the gigantic fish, one of the biggest freshwater fish in the world, can enjoy perfect protection against piranha attacks.
Science bits and news from other sites:
Massive black hole is last survivor of its galaxy. There is no end to the interesting observations made by the Hubble telescope. A supermassive black hole, named HLX-1, 20,000 times more massive than the sun, was just spotted 290 million light-years away at the edge of the spiral galaxy ESO 243-49. The location is particularly odd because gigantic black holes like HLX-1 are usually found at the center, not the periphery, of galaxies. The suspicion is that this black hole is the only remnant of a galaxy that has disintegrated. The presence of red light in the black hole could be indicative of the presence of very young stars, roughly 200 million years old, orbiting around the black hole. Since large galaxies engulf smaller galaxies in their proximity, it is likely that HLX-1 originally formed at the center of a dwarf galaxy that came too close to ESO 243-49, and the larger galaxy “ate” most of its stars, leaving behind the exposed central black hole. The young stars around the black hole may be all the remains of the dwarf galaxy. It is possible that the black hole will be sucked into the ESO 243-49 galaxy as well, although it is also possible that its orbit is stable and will continue to circle the galaxy.
The origins of life: warm little ponds or the deep sea? The origins of life still remain mysterious, since we do not know exactly what catalyzed the emergence of life from chemical systems. We know that life started about 4 billion years ago on our planet, and one of the hypotheses is that life must have originated in hydrothermal vents in the deep sea. This hypothesis is based on the premise that amino-acid synthesis could have occurred deep in the Earth's crust and then spewed into into cooler waters through hydrothermal vents. The hypothesis is attractive because of the methane and ammonia are present in hydrothermal vent regions, but were not present in the Earth’s primitive atmosphere. The presence of numerous species of extremophiles (microorganisms that thrive in extreme conditions) around the hydrothermal deep-sea vents further cemented the idea that the hydrothermal vent scenario was a possible cradle of first life. Darwin did not really write about the origins of life, but in a letter to one of his colleagues, he ventured that life could have originated “in some warm little pond, with all sorts of ammonia and phosphoric salts, light, heat, electricity, etc. present.” A new study published in PNAS seems to indicate that Darwin may have been right in his hunch. The paper suggests that inland pools of condensed and cooled geothermal vapor have the ideal characteristics for the origin of life. All living cells are rich in potassium, zinc, manganese, and phosphate ions, and these are not prevalent in marine environments. But geysers, mud pots, etc. bring precisely those ions to the surface. Water containing these ions could have gathered in shallow pools which could have been fostered the development of life. The next step is to model the conditions in the lab and see if this type of conditions can foster the development of biologically relevant macromolecules. The hypothesis is controversial and other scientists think it’s unlikely, because 4 billion years ago, there was very little land and those pools would have been unstable. Other scientists think that geothermal active areas are a plausible staging area for the origin of life, but the hypothesis is based on the chemical composition of modern cells and we do not if this is reflective of the initial conditions were life first arose.
Extremophiles and astrobiology. And since we have mentioned extremophiles, I would like to point to a brand new blog that seems very promising. The blog is called Extremo Files. The pun in the title refers to extremophiles, which are microbes that live in extreme conditions such as hot springs, acidic rivers, or sub-zero temperatures. Astrobiology, according to NASA, is “the study of the origin, evolution, distribution, and future of life in the universe.” Astrobiology sounds like it would be about extraterrestrial life, but it is actually grounded on our planet. The basis of astrobiology is the study of the most extreme places on Earth, assuming these could reproduce biologically relevant conditions elsewhere in the universe. For example, the Atacama Desert could be a surrogate for Mars and Antarctic lakes could be Europa. If microbes can survive in extreme deserts or sub-zero temperatures, maybe they can exist in other planets. Thus, the Earth-based extremophiles are “astrobiological ambassadors”, because if there is life in other planets, it is likely to resemble this extremely interesting (no pun intended) group of microbes, the extremophiles. If you’re wondering where you read about extremophiles before, the whole arsenic DNA controversy involves an extremophile isolated from Mono Lake in California.
The Physics of Ponytails. You may be tempted to think that this group of physicists at Cambridge, England, really had too much time on their hands. But thanks to their model, if you have short hair and have always wanted to grow your hair long and imagine what it would look like in a ponytail, now you can use their equation to predict the looks of your ponytail. Will it be a thing, long mane, or will it fan out (like mine)? The physicists assumed that hair behaves like a stream of fluid, with the density decreasing with the distance to the scrunchie or rubber band. The Ponytail Shape Equation (the result is called Rapunzel number, so don’t say scientists have no sense of humor), reported this week in Physical Review Letters, explains different hair geometries (which is fun) and also the dynamic behavior of bundles of fibers. (which is more useful). A short ponytail of springy hair, characterized by a low Rapunzel number, fans outward (when I wear my hair in a ponytail, this is what I get). A long ponytail with a high Rapunzel number hangs down, because the pull of gravity overcomes the springiness. The equation could be useful in other realms such as fiberglass and wool. The physicists remarked that a head of hair with ~100,000 strands is indeed a complex system. They took into account elasticity, density and curliness. But in any case, how did they even get started on this research? The answer: cosmetics. Unilever, a hair product company, funded the study. They hope to use the equation to develop better hair products.
The Mystery of the Exploding Manure Pits. You probably do not want to see the words “explosion” and “manure” in the same sentence. But I’m still going to tell you a story about really big, exploding pools of pig manure. Why? Because it is important for our environment and for the welfare of the animals. I certainly had no idea this sort of things happened, I guess the press does not highlight it, but it turns out that in recent years there have been serious explosions that have destroyed several pig farms in the American Midwest, causing the death of thousands of pigs and losses in the millions of dollars. But why is this happening now. As you know, methane is produced by bacteria living in pits of manure, and methane is very flammable. It is also odorless. The methane gas in your kitchen smells bad because hydrogen sulfide is added so that one can smell leaks and prevent a catastrophe. There has always been methane in manure pits, so why are these explosions happening now. Recently, foam has been seen on the surface of manure pits, sometimes even as deep as 4 feet! Methane is trapped in the little foam bubbles. And because it is concentrated, all is takes is a spark, and boom! But why are these deep manure pools foaming at the top? The answer is: the pigs’ diet. Hogs are now fed a diet heavy in distiller’s dried grains with solubles (DDGS), a side product of ethanol production: 3.2 million tons of DDGS are produced annually. So we feed it to the cows, and to the pigs. DDGS has a different protein and fat profile than soybean or corn feed, as well as significant levels of antibiotics. These factors influence the makeup of the microbial community in the pigs’ guts. The culprit bacteria still has to be identified, but University of Minnesota scientists suspect that filamentous bacteria are causing the foaming. But the actual culprit is our production policy, that is yielding tons of by-products that the animals were never meant to eat, and that end up causing, well, one shouldn’t mince words, tons and tons of explosive shit. It’s time to take a good look at what we eat and what it takes to produce what we consume. And be thankful that I'm posting a cute little piggy in boots and not a picture of foaming feces.