The top five most-pirated nautical zones from 2001 to 2012.
A great visualization of where the stratosphere is thanks to Mt. Etna.
Edgley Design builds family home around 100-year-old pear tree in south London »
Proportional risk
I've begun to develop a strong fear of the weather. Lightning and wind also terrify me. When someone is afraid of flying, there are statistics which could help them understand how little a risk they are actually taking. With this statistic method in mind, is there anything I could remind myself of when I begin to become frightened, that could help relax me a bit? Thank you :)
The National Safety Council organized a handy chart of “What are the Odds of Dying From” that has some handy statistics. There’s a lot more things that we are significantly more at risk for statistically than lightning. For instance you have a 1 in 672 chance of dying as a pedestrian in your life while a 1 in 174,426 chance of dying from lightning. Yet we don’t carry the same fear when walking as we do for lightning.
Something to consider here, we’re much more often “exposed” to being pedestrians than we are exposed to lightning, so this makes a bit of sense that the numbers are so skewed, but the point of fear still stands.
Lightning is serious business, but as I said earlier we need to approach lightning intelligently.
If you look at the an analysis of lightning deaths in the US about two thirds of incidents occurred to people engaged in outdoor activities. So basically people that are outside enjoying the day when a storm comes along, and they decide to either watch the storm from an unsafe place, or keep going with the activity. Going further into outdoor “leisure” activities, of that two thirds about 35% of those activities were water related (largely fishing, but hey, why not looks at the study yourself!).
Worth mentioning, the study also pointed out that 79% of victims were male - being okay with risky behaviours doesn’t make you cool and tough, it makes you an idiot. As the study put it:
Possible explanationsfor this finding are that males are unaware of all the dangers associated with lightning, are more likely tobe in vulnerable situations, are unwilling to be inconvenienced by the threat of lightning, are in situationsthat make it difficult to get to a safe place in a timely manner, don’t react quickly to the lightning threat, orany combination of these explanations. In short, because of their behavior, males are at a higher risk ofbeing struck and, consequently, are struck and killed by lightning more often than females.
Here’s a breakdown of activities people are doing when they die from a lightning strike:
Notice these are all things that are outside! The study stated that things that contributed to lightning fatalities were people’s unwillingness to postpone activities, not being aware of approaching storms (you’re either weatherwise, or otherwise!), being in a vulnerable location, an inability or unwillingness to get to a safe place.
So how do we be safe during a thunderstorm? Do as the NOAA says “when thunder roars, go indoors”! If you know there are going to be storms that day stay alert and take a glance at a radar map every now and then (lord knows you probably have a smart phone), and have an idea of where you’ll go when a storm is near. If you’re unable to get indoors avoid hilltops, isolated tall objects like poles or trees, spread out if you’re in a group, and try to avoid wet items and areas - these won’t make you safe, but will slightly decrease your risk. The only completely safe action is getting inside a building or vehicle.
Have a look over this page on lightning safety and these tips for more info.
So bottom line, should you have a healthy respect for lightning? Yes. Should you be terrified of lightning? No. Be smart and follow the safety tips, you’ll be alright.
Thanks for reading, and I hope this helped!
Let's elect politicians who could pass a high school science class
I’m re-posting this comic because I live in America.
Here, the places I love most in the world are gripped by drought. I’m thinking of giving away my winter tracking guides because there’s never enough snow. Climate change is knocking on our door, and the fact that it’s already so evident is a bad sign: it means that we’re headed for a lot more warming.
But we can deal with this, people. We’re brilliant. We’re brave. What we need - besides some kinda magical cooling ray - is a batch of elected officials who are ready to be brave alongside us.
If climate change bums you out, don’t lose heart: it means you’re strong. You’ve personally confronted a huge issue. Why let yourself be governed by scared people who can’t face it, who equivocate and attack scientists and hide their heads in the sand?
My brave dear friends: let’s get our climate vote on.
A recent study analyzed DNA from the teeth of Bronze Age people who lived in Europe and Asia. It found evidence of plague infection, from the Yersinia pestis bacterium, dating to 6,000 years ago! What later became the Black Plague was, 6,000 years ago, spread only through contaminated food or human-to-human contact. It was later that a genetic mutation in the bacterium allowed them to survive in the guts of fleas – researchers estimate around the turn of the 1st century BCE.
The black death’s early co-existence with humans, and its ability to pass person-to-person, also suggests an interesting new avenue for forensic diagnosing. The yersinia pestis bacterium may have been responsible for early epidemics, such as the plague of Athens. Many early plagues are known to have passed person-to-person so scientists previously discounted yersinia pestis from the running. But proving which ancient plagues were really the Black Death in an earlier form is a subject for another study.
As part of our Asteroid Redirect Mission (ARM), we plan to send a robotic spacecraft to an asteroid tens of millions of miles away from Earth, capture a multi-ton boulder and bring it to an orbit near the moon for future crew exploration.
This mission to visit a large near-Earth asteroid is part of our plan to advance the new technologies and spaceflight experience needed for a human mission to the Martian system in the 2030s.
The robotic spacecraft, powered by the most advanced solar electric propulsion system, will travel for about 18 months to the target asteroid.
After the spacecraft arrives and the multi-ton boulder is collected from the surface, the spacecraft will hover near the asteroid to create a gravitational attraction that will slightly change the asteroid’s trajectory.
After the enhanced gravity tractor demonstration is compete, the robotic vehicle will deliver the boulder into a stable orbit near the moon. During the transit, the boulder will be further imaged and studied by the spacecraft.
Astronauts aboard the Orion spacecraft will launch on the Space Launch System rocket to explore the returned boulder.
Orion will dock with the robotic vehicle that still has the boulder in its grasp.
While docked, two crew members on spacewalks will explore the boulder and collect samples to bring back to Earth for further study.
The astronauts and collected samples will return to Earth in the Orion spacecraft.
This mission will demonstrate future Mars-level exploration missions closer to home and will fly a mission with technologies and real life operational constraints that we’ll encounter on the way to the Red Planet. A few of the capabilities it will help us test include:
Solar Electric Propulsion – Using advanced Solar Electric Propulsion (SEP) technologies is an important part of future missions to send larger payloads into deep space and to the Mars system. Unlike chemical propulsion, which uses combustion and a nozzle to generate thrust, SEP uses electricity from solar arrays to create electromagnetic fields to accelerate and expel charged atoms (ions) to create a very low thrust with a very efficient use of propellant.
Trajectory and Navigation – When we move the massive asteroid boulder using low-thrust propulsion and leveraging the gravity fields of Earth and the moon, we’ll validate critical technologies for the future Mars missions.
Advances in Spacesuits – Spacesuits designed to operate in deep space and for the Mars surface will require upgrades to the portable life support system (PLSS). We are working on advanced PLSS that will protect astronauts on Mars or in deep space by improving carbon dioxide removal, humidity control and oxygen regulation. We are also improving mobility by evaluating advances in gloves to improve thermal capacity and dexterity.
Sample Collection and Containment Techniques – This experience will help us prepare to return samples from Mars through the development of new techniques for safe sample collection and containment. These techniques will ensure that humans do not contaminate the samples with microbes from Earth, while protecting our planet from any potential hazards in the samples that are returned.
Rendezvous and Docking Capabilities – Future human missions to Mars will require new capabilities to rendezvous and dock spacecraft in deep space. We will advance the current system we’ve developed with the international partners aboard the International Space Station.
Moving from spaceflight a couple hundred miles off Earth to the proving ground environment (40,000 miles beyond the moon) will allow us to start accumulating experience farther than humans have ever traveled in space.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com
The largest known Egyptian obelisk is called the “unfinished obelisk”, which today can be found exactly where it was once semi-carved from the solid bedrock. This stone block was intended to be a 120ft tall obelisk. It is estimated that a block of granite this size would easily weigh more than a 1000 tons, some geologists have suggested a figure in the region of 1100 tons – 1150 tons.
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Geologists recently found evidence of ancient life in Greenland which they think dates to 3.7 billion years ago. If their findings are confirmed, that would make the fossils the oldest evidence of life yet known. The great age of the fossils makes reconstructing the evolution of life from the chemicals naturally present on the early Earth more difficult. You see, the fossils are too old. It leaves little time for evolution to have occurred, and puts the process of life emerging and evolving close to a time when Earth was being bombarded by destructive asteroids.
Really? You’re really going to say this?
First off: see this?
This is my masters’ degree in anthropology. I’d show you my BA, but it’s at my parents’ house. I’m three and a half years into a PhD in physical anthropology. I’ve been employed to do physical anthropology at one of the world’s best natural history museums. My area of study? Teeth and diets. I’m not here to argue veganism or vegetarianism, I’m here to tell you, point by point, why you’re devastatingly misinformed about our place in the primate family tree, along with my peer-reviewed sources behind the jump. I know we live in a “post-truth” society so maybe being presented with the overwhelming consensus of the scientists who currently work with this material is meaningless to you, and honestly, this probably isn’t going to make a bit of difference for you, but I can’t let this slide. Not in this house built on blood and honor. And teeth.
1. The evidence for being closely related to chimpanzees is vast and well-understood thanks to advances in DNA analysis. We share a huge amount of DNA with them, and not just repeating patterns in non-coding DNA. We have numerous genes that are identical and likely diverged around 7 million years ago, when Sahelanthropus tschadensis was roaming the earth. S. tschadensis was a woodland species with basal ape and basal human-line traits. The most notable was the positioning of the foramen magnum towards the central base of the skull and not emerging from the back suggests bipedality. This, along with other traits such as small canines worn at the tip, which implies a reduced or absent C/P3 honing complex (the diastema), suggests that this is actually a basal trait and the pronounced diastema we see in other species was a trait that came later. But more on that later- back to chimps and what we mean by sharing DNA. Our chromosomes and chimp chromosomes are structured far more like each other than other mammals. Furthermore, the genes located on these chromosomes are very similar. Chromosome 2, for instance, is nearly identical to two chimpanzee chromosomes. (Chromosome 2 in humans, Neanderthals, and Denisovans is different from Chromosome 2 found in apes and is actually the remnant of an ancient mutation where Chromosome 2 and 3 merged- you can see that from its vestigial centromeres and the genes found on it. We can’t get DNA from fossil material, but Neanderthal and Denisovan subfossils have demonstrated that this reduced chromosome count- we have one fewer pair than apes- is a typical trait of the Homo genus). Here’s a side by side comparison of Human and chimpanzee chromosomes.
Gene coding regions are colored- bands at the same place mean that there’s two identical genes at that locus. Our similarities to lemurs, on the other hand, aren’t on homologous chromosomes. We have similar coding around the centromeres but the genes express themselves differently. The structure of non-ape primate genes is also significantly different; when the first chromosomal comparisons were done between humans and lemurs back in the 1990s, it was discovered that lemurs have much more highly-concentrated heterochromatin at their centromeres, whereas the structure of human and chimpanzee centromeres is similar. The major differences in chimp and human DNA are in the noncoding regions; most of our genes have identical structures.
2. All primates evolved from a lemur-like organism, not just humans. Here’s one of them. I’ve seen her in person. Pretty cool, huh?
Her name is Ida and she’s a member of the genus Darwinius. But that’s just like saying all primates evolved from something that was basically a tree shrew- which is also true. See, one of the main points of evolution is that organisms are continually changing throughout time. We didn’t jump from lemur-like organism to human; changes were slow and gradual and the lineage isn’t really a straight tree. The fossil species we have and know lead to different lines branching out. Some things died off, some things flourished. Heck, look at the Miocene- twelve million years ago, there were hundreds of ape species. Now there’s twenty-three. (Sixteen gibbons, two chimp species, two gorilla species, two orangutan species, and one human species. There’s also some subspecies of gorilla and gibbon, but I’m only counting the primary species.) It’s hard to trace things back, but saying that we evolved from lemur-like species is obtuse and obfuscates the real point, which is that Homo and Pan descended from a relatively recent-in-the-grand-scheme-of-things common ancestor.
3. Our dentition is unique to the extant primates, but not australopithecines. Our teeth look very much like other members of the genus Homo, the extinct ones, as well as many of the australopithecines. We also have very similar enamel proportions to gracile australopithecines; apes have much thinner enamel overall.
But what did australopithecines eat?
Everything. We know they were eating fruits and nuts based on microwear analysis and strontium analysis, but we also know they were eating meat- and in pretty decent quantity, too. We’ve found all kinds of butchering sites dating back millions of years and in association with Australopithecus garhi, the earliest tool user, but we can also see this in tapeworm evolution. There’s many, many species of tapeworm in several genera. But three of them, in the genus Taenia, are only found in humans. And these species diverged from… carnivore tapeworms. Their closest relatives infect African carnivores like hyenas and wild dogs.
Tapeworms that are adapted to the specific gut of their host species need a certain environment, as well as a specific cycle of infection so that it can reproduce. A tapeworm that infects hyenas is going to be less successful if it somehow makes the jump to a horse. But if the hyena tapeworm was able to adapt to our gut, that suggests that our stomach was hospitable enough for them chemically to survive- which brings me to the intestines.
4. Our intestines are also unique. Yes, we have longer intestines than carnivores, but we also don’t have cecums like herbivores. We are omnivores and that means we still needed to retain the ability to digest plants.
The key to being omnivores is omni. All. I’m not saying we should only be eating meat, I’m saying our ancestors ate a varied diet that included all kinds of things. If we weren’t omnivores, why would we have lost the cecum’s function? Why is the human appendix only a reservoir for the lymphatic system, as it is in carnivores? The cecum is an extremely important organ in herbivores, as it houses the bacteria needed to break down cellulose and fully utilize fiber from leaves. But we don’t have that. Instead, we compensate with a long gut. Our ancestors absolutely did eat fruits and nuts and berries, but they also ate other stuff. Like scavenged carcasses and bugs and probably anything they could fit in their mouths. Which- actually, primate mouths are interesting. Humans and chimpanzees have enclosed oral cavities, thick tongues, and jaw angles much more like herbivores than carnivores- suggesting a herbivorous ancestor. That’s not something I’m arguing against at all. But again, we have adaptations for eating meat and processing animal protein because we are an extremely opportunistic species.
5. Our canines are true canines. First, semantics: having a diastema does not canine teeth make. We refer to the canine teeth by position- even herbivores, like horses, have them. They’re the teeth that come right after the incisors. All heterodonts have the potential same basic tooth types- incisors, canines, premolars, molars- in various combinations and arrangements. Some species don’t have one type of teeth, others don’t have any- but it’s silly to say that the canine teeth aren’t canine teeth just because they don’t serve the same function as a gorilla’s or a bear’s or some other animal’s. It’s basic derived versus primitive characteristics.
Now that we’ve got semantics out of the way, let’s talk about that diastema. The lost diastema is a derived trait, which means that our ancestors had it and we lost it over time. All other extant non-Homo primates have a canine diastema. All of them. However, when you look at australopithecines, we see that many of them either don’t have it or have it in a reduced capacity. At the earliest known hominin site, Lukeino, we see Orrorin tugenensis with reduced canines compared to ape fossils and modern apes- and… you do know that apes don’t use their canines for eating meat, right? Like, primate canines serve a very different purpose than carnivorans’ canines. It’s suggested that the large canines are for social display moreso than anything dietary- bigger, more threatening teeth are useful if you’re a gorilla or chimpanzee fighting to the top of your group’s social structure.
I’m going to refer you to a blog post written by Dr. John Hawks, a good friend of my advisor and generally a pretty cool guy. He’s got a nice writeup on the evolution of hominin teeth and how the human line’s teeth have changed through time.
Also, of course our teeth are going to be smaller. When we compare archaic Homo sapiens fossils to modern skeletons, their teeth and jaws are much more robust. This is likely related to the introduction of soft foods- and by soft, I mean cooked grain mush- to the diet around the time of domestication, right before the population explosion that happened about 10k years ago. In general, post-domestication human jaws are much smaller and more crowded than any other humans and hominins that came before.
6: Neanderthals did die out, but not in a catastrophic event like we think of with dinosaurs. While there are no living Neanderthals today that we would classify as Homo neanderthalensis, there is plenty of evidence that we interbred and likely outcompeted them as a species due to our overwhelmingly large population size (hypothesized based on number and locations of remains found). While there’s only a small percentage of Neanderthal mitochondrial DNA lines in human populations today, it’s quite likely we lost a lot of that due to genetic drift and population migration- Neanderthals, after all, had a much more limited range than Homo sapiens sapiens. Their eventual extinction is a mosaic of events- outcompetition plus assimilation. The line between Homo sapiens sapiens and Homo neanderthalensis/Homo sapiens neanderthalensis is blurry- there’s some physical anthropologists who actually think we should be including them within our species as a subspecies- but they are extinct in that the specific subset of hominins with distinct karyotypes and potential phenotypes no longer exists.
And if you don’t know, now you know.
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Gaming, Science, History, Feminism, and all other manners of geekery. Also a lot of dance
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