An innovative NASA would be nice [Pharyngula]

NASA has put out a call for novel ideas in space exploration, which I think is an excellent way to do science. More creativity!
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But this feels like they’re just pandering to me (I know, they’re not): building robotic squid to explore the oceans of Europa? What’s not to love about that idea?

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Source: Bio Science blog

Oliver Sacks has died [Pharyngula]

I have been increasingly conscious, for the last 10 years or so, of deaths among my contemporaries. My generation is on the way out, and each death I have felt as an abruption, a tearing away of part of myself. There will be no one like us when we are gone, but then there is no one like anyone else, ever. When people die, they cannot be replaced. They leave holes that cannot be filled, for it is the fate — the genetic and neural fate — of every human being to be a unique individual, to find his own path, to live his own life, to die his own death.
–Oliver Sacks

The man himself has died.
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Source: Bio Science blog

Why did Skylab die? [Greg Laden's Blog]

Skylab came up in conversation the other day. And then I ran into Amy Shira Teitel’s video. So, naturally, a quick blog post.
Skylab was brought down, ultimately, by interaction with the upper reaches of the atmosphere, which was in turn made more likely by solar activity. But, both the nature and extent of solar activity of this type, and its effects on the atmosphere, were not understood when Skylab was being designed and deployed. Indeed, understanding this set of phenomena was a contribution made by Skylab science. Had Skylab been launched after, rather than before, this was better understood, it may have been put into higher orbit, or it may have been equipped with boosters (like the International Space Station is) to periodically raise the orbit.
Anyway, eventually, the orbiting research lab came down, and you may (or may not) remember all the press, the jokes, the anxiety, the fun…
Anyway, Amy has this piece on what NASA did and didn’t do about Skylab’s demise.
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Source: Env blog

Report: Homeowners Could Save Up To 40% On Electricity by Flexing Their Demand

Buy, make, or eliminate – these are the three main ways that we have gone about meeting our electricity needs for the past century. But, according to a new report by the Rocky Mountain Institute, a rapidly growing fourth option is appearing across the country and offering a way for homeowners to decrease their monthly bills.This fourth possibility centres on “demand flexibility” – which refers to the increasing ability for homeowners to choose when they use electricity throughout the day. Examples include delaying when water is heated after our shower in the morning to shifting when an electric car parked in the garage is charged at night.
In their report, RMI presents four graphs to show how demand flexibility differs from buying, making, or eliminating electricity use. The first graph shows what demand looks like during the day when we simply buy electricity as we need it. The middle chart shows how things look when we generate some of our electricity needs onsite with a bit of rooftop solar PV, decreasing our demand from the power grid at certain times. The chart on the right shows how energy efficiency can provide an overall reduction of total electricity demand.
RMI (2015)
In their fourth graph, RMI shows what could happen if we were to shift our electricity demand to “off-peak” periods. That is, what if you were to do all of the things you wanted to in the day, but change when you did them (either manually, or through automatic oprtions like time-delay settings on your washing machine). While some of your electricity demand can’t be shifted too easily – for example, to eliminate demand for electricity for lighting during a certain period would require you to either turn off your lights or install some sort of energy storage technology – there are many activities that could be shifted in time. The result of this shifting is the green dashed line shown on this graph, which is much more flat (i.e. less “peaky”) than the normal load.
RMI (2015)
This flexibility is a departure from how we have historically met our electricity needs at home. While industrial facilities have long been financially incentivized to shift their demand for electricity away from “peak” demand periods, residential consumers have had little reason to shift their demand profiles. However, with the increasing availability of time-of-use pricing agreements for residential electricity consumers, more and more people are seeing an opportunity to save money by changing when they use electricity.
With time-of-use pricing structures, you pay less for electricity during periods of low demand (for example, in the middle of the night). Conversely, you pay more for a kilowatt-hour of electricity during “peak” house (for example, in the afternoon on a summer day when air conditioners are running full-speed and people are getting home from work and school). According to RMI’s report, if your utility offers time-of-use rates, you could reduce your power bill by 10-40% by moving some of your peak demand to off-peak periods in this way.
In France, shifting demand from residential water heaters are currently used to reduce winter peak electricity demand by an estimated 5 Gigawatts (5%). This peak reduction is achieved by using timers and switches to shift when water is heated during the day (consumers can override this delay if they wish to). Practically speaking, this set-up means that many water heaters in France do not automatically re-heat after morning (or evening) showers. Rather, they delay reheating until lower demand periods. Given that 43% of residential electricity use in France is dedicated to water heating, this shift is no small matter.
International Energy Agency (IEA) Technology Roadmap: Energy Storage – Technology Annex (2014)
Shifting electricity demand away from peak periods has benefits for not only consumers, but also for utilities and the electricity grid:
Consumers can save money while still receiving the same service.
By lowering peak demand, utilities can avoid building “peakers” – the power plants that are only used for short periods of time to meet peak demand and then sit for the rest of the year, making them a quite inefficient asset.
Decreasing peak demand can lower the stress and strain on aging transmission and distribution infrastructure in the electricity grid.
In turn, demand shifting can be financially beneficial even for those consumers who do not have electricity time-of-use pricing options in their service areas. According to RMI, demand flexibility “can unlock $13 billion per year of avoided grid investment” meaning that consumers would presumably pay less for their electricity over time due to a decreased need for infrastructure investments. However, it would be difficult for consumers to accurately measure how this type of savings impacts their monthly electricity bill.
That being said, according to RMI’s report, roughly 65 million customers in the United States already have access to some type of time-of-use pricing agreement for their electricity use. They go on to conclude that:
“In the residential sector alone, widespread implementation of demand flexibility can save 10–15% of potential grid costs, and customers can cut their electric bills 10–40% with rates and technologies that exist today.”
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Comments of the Week #74: from the Universe’s age to the love of science [Starts With A Bang]

“To me there has never been a higher source of earthly honor or distinction than that connected with advances in science.” -Isaac Newton

And the advances continue, not just here at Starts With A Bang but everywhere humans are engaged in the practice of gathering knowledge about the world and Universe itself. This past week, we covered:

And for those of you who want to catch up on nuclear fusion, check my latest over at Forbes:

Later this weekend (probably on Sunday), the first advance copies of Chapter 2: A Relatively Different Story: How Einstein’s Relativity Revolutionized Space, Time, And The Universe will go out to my Patreon supporters, so make sure you don’t miss out for a spectacular preview of my upcoming book, Beyond The Galaxy. Now, dive with me into our Comments of the Week!

Image credit: NASA, ESA, and A. Feild (STScI), via http://www.spacetelescope.org/images/heic0805c/.

Image credit: NASA, ESA, and A. Feild (STScI), via http://www.spacetelescope.org/images/heic0805c/.

From Sinisa Lazarek on the puzzling problem of special relativity: “what I find fascinating and bizzare at the same time is if you view it from a POV of a photon being created i.e at CMB time and traveling through spacetime.. is that photon will colide with things that don’t yet exist in his timeline.. i.e. with a gold atom created in star cores which is 2 billion years in the future from a photon’s clock.. in photon’s reference that star hasn’t even been born.. yet in some other reference frame you could observe that photon hiting that gold atom somewhere in space. If photon could think, what would he say? what the hell did I just hit? where did this atom come from??”

Imagine not that you were a photon, since the laws of physics return instantaneous answers at the speed of light (the hazards of being a null vector), but rather that you were the very first observer ever to be created out of matter, say, 2 billion years after the Big Bang. Out in the great distance, there’s a CMB that’s some four times as hot as ours is at present, the largest galaxy clusters contain only hundreds (instead of thousands) of galaxies, the visible Universe is only 14 billion light years in diameter instead of the present 93, and the galaxies that do exist are bluer, smaller and far less evolved than the ones we know today.

Image credit: NASA, ESA, P. van Dokkum (Yale University), S. Patel (Leiden University), and the 3D-HST Team.

Image credit: NASA, ESA, P. van Dokkum (Yale University), S. Patel (Leiden University), and the 3D-HST Team.

Yet if you got into a spaceship, accelerated at 9.8 m/s^2 for about 30 years in your frame of reference, and then just coasted, you’d be able — assuming you didn’t run into something and fry yourself — to travel through billions of years of cosmic evolution. When you looked out your front windshield, the Universe would appear to evolve incredibly rapidly, as the galaxies you’d encounter would change tremendously in short order. The ones behind you, contrariwise would still appear just as ancient as when you left, since the photons would struggle to overtake you.

But the big surprise would come if you screeched to a halt, and slipped back into the CMB’s rest frame.

Image credit: NASA; ESA; G. Illingworth, D. Magee, and P. Oesch, University of California, Santa Cruz; R. Bouwens, Leiden University; and the HUDF09 Team.

Image credit: NASA; ESA; G. Illingworth, D. Magee, and P. Oesch, University of California, Santa Cruz; R. Bouwens, Leiden University; and the HUDF09 Team.

At that moment, the Universe would look like whatever it looks like in its rest frame at its present age, your relativistic journey notwithstanding. You would essentially suffer the craziest episode of time dilation of all, where everyone you knew had been dead for billions of years, where your own star had died and very likely, your parent galaxy had long since merged with another. The Universe would come to be dominated by dark energy, meaning that your original location would now be unreachable, and that you literally — unless you invent a wormhole — you can never go back.

Physics sure is strange, isn’t it? Thanks, Einstein.

Image credit: NASA, ESA, Jean-Paul Kneib (Laboratoire d’Astrophysique de Marseille) et al.

Image credit: NASA, ESA, Jean-Paul Kneib (Laboratoire d’Astrophysique de Marseille) et al.

From PB on whether this could every practically happen: “While technically correct, such an accelerated galaxy is extremely unlikely.”

Typically, galaxies reach peculiar velocities of a few hundred to the low thousands of km/s. In extreme cases, we’ve seen speeds in the tens of thousands of km/s. To reach near-light speed? Yes, it’s exceedingly unlikely. But this is the whole purpose of a thought experiment: to test the scenarios unachievable in the physical Universe itself! While galaxies might not get there, individual star systems can come far closer, and of course a spacefaring civilization… well, call me in 1,000 years and let’s see where we are.

Image credit: Stuart Palley, from his instagram feed at https://instagram.com/stuartpalley/.

Image credit: Stuart Palley, from his instagram feed at https://instagram.com/stuartpalley/.

From PJ on California’s (and other) wildfires: “From a firies point of view, I can say there is no beauty in a fire situation. There is no time to enjoy such things – rather, observe the extent, calculate the risks, endeavor to extinguish; ensure the safety of your men & others, stock, then property.
I entirely agree with the photographer that education is an absolute necessity for those living in the bush. Goodness knows how many campaigns we would run each year in the off-season to try & make property owners aware of their surrounds.”

It’s a very hard task to think of beauty when you’re someone who either works firsthand with or is close to the destruction. I’ve lived up in the Pacific Northwest (Oregon/Washington states) for the past seven years, and this year, all three coastal states (OR, WA, CA) are experiencing drought and rampant wildfires. The air quality where I am the past few weeks has been awful, the sunsets have been reddish for hours, and just last weekend, a 10,000 gallon propane tank just a few miles from my house almost went up in flames. Lit cigarettes or unattended campfires have been the cause of nearly half of the wildfires around here.

Image credit: Stuart Palley, from his instagram feed at https://instagram.com/stuartpalley/.

Image credit: Stuart Palley, from his instagram feed at https://instagram.com/stuartpalley/.

And yet, there is a beauty to it all. It’s kind of amazing that Stuart was able to capture that aspect amid all the chaos. Somewhat unexpectedly, he reached out to me this past week, having seen my article:

Stuart Palley here, photographer out in Los Angeles working on the Terra Flamma project. Thanks for your article detailing my work and for your insight on the wildfire and drought issue. I enjoyed your treatment of the work and words as well.
I like the wildfire song too.
Thank you for your support!
That’s good stuff, and I hope you liked it — and that you never underestimate its destructive power — too.
Image credit: The pre-launch Planck Sky Model: a model of sky emission at submillimetre to centimetre wavelengths — Delabrouille, J. et al.Astron.Astrophys. 553 (2013) A96 arXiv:1207.3675 [astro-ph.CO].

Image credit: The pre-launch Planck Sky Model: a model of sky emission at submillimetre to centimetre wavelengths — Delabrouille, J. et al.Astron.Astrophys. 553 (2013) A96 arXiv:1207.3675 [astro-ph.CO].

From Michael Kelsey on how fast we’re moving through space: “Ethan, I must be missing something really obvious. Toward the end of your piece, you wrote, “[T]he Solar System moves relative to the CMB at 368 ± 2 km/s, and that when you throw in the motion of the local group, you get that all of it — the Sun, the Milky Way, Andromeda and all the others — are moving at 627 ± 22 km/s relative to the CMB.”The first half of that is just converting the +/-3.354 mK dipole into a velocity (z = 1.23e-3, so v = zc = 368 km/s). But how do you get the 627 km/s? Is that the motion of the center of mass of the Local Group relative to the CMB? Do you get that by summing the apparent (peculiar) motions of the other members of the LG, along with the Sun’s galactic orbital motion?”

So there are two pieces to this, as you identify: our total motion relative to the CMB, which we get simply from the CMB dipole: 368 km/s. The uncertainty there, by the way? That isn’t a measurement uncertainty! That extra ± 2 km/s comes from our ignorance of how intrinsically large (or small) the actual primordial cosmic dipole is. We know it exists (or ought to exist), but we have no measurable way to disentangle the CMB’s dipole from ours. If it’s the same magnitude as the other multipole moments, it ought to be ± 1-or-2 km/s, and so that’s where our uncertainty comes from.

Image credit: Cosmography of the Local Universe — Courtois, Helene M. et al. Astron.J. 146 (2013) 69 arXiv:1306.0091 [astro-ph.CO].

Image credit: Cosmography of the Local Universe — Courtois, Helene M. et al. Astron.J. 146 (2013) 69 arXiv:1306.0091 [astro-ph.CO].

But the second piece is that we can measure the Earth’s motion around the Sun, and the Sun’s motion around the galaxy (which has an uncertainty of around ± 20 km/s in magnitude, mind you), and the Milky Way’s motion towards Andromeda and the other local group objects, and we’ll get a number that’s close to (but just under) 300 km/s total for our motion through this part of the cosmos. But it’s nearly opposite to the direction of the CMB dipole, and so therefore the entire local group must be moving (using vector addition) at some 627 km/s relative to the CMB, with the uncertainty mostly coming from the Sun’s motion around the galaxy.

Hope this helps!

Image credit: ESA and the Planck Collaboration.

Image credit: ESA and the Planck Collaboration.

From Doug Henderson on the CMB: “I was puzzled by this statement: “Prior to that time, some 380,000 years ago, it was too hot to form them, as photon collisions would immediately blast them apart, ionizing their components.””

I was puzzled by your puzzlement, initially, because my mind just read it and went, “Yeah, CMB! 380,000 years from the Big Bang, and then we come to the present.” Because that’s what I write. That’s what I always write. And so that I accidentally wrote “years ago” instead, I didn’t even catch it at all.

So there’s your proof: I’m not a robot. I’m a human, an error-prone human. I’ve fixed it in the text without much fanfare, but I wanted to acknowledge my mistake. Thanks for the catch.

Image credit: NASA / JPL-Caltech.

Image credit: NASA / JPL-Caltech.

From Denier on the evaporation rate of black holes: “While it should have been obvious, I didn’t realize until reading this article that there is not a single moderate or large black hole that has lost even a single atom’s worth of mass to Hawking Radiation in the history of our universe to this point. Even if a black hole was completely cut off from being able to absorb any matter for the past 13 billion years, it would still absorb more energy from the CMB than it could lose in Hawking Radiation.”

This is a lot of fun, actually, and lucky for you, something I worked through in detail last year in one of my Ask Ethans. Here’s an excerpt of the relevant bits:

In fact — although you actually have to do the quantum field theory calculations in curved spacetime to find this out — Hawking radiation predicts that you’ll get a blackbody spectrum of photons with a temperature given by:

which is a temperature of less than one microKelvin for a black hole the mass of our Sun, less than one picoKelvin for the black hole at the center of our galaxy, and just a few tens of attoKelvins for the largest known black hole. These decay rates that this radiation corresponds to are so small that it means that black holes will continue to grow so long as they continue to absorb even one proton’s worth of material per present-age-of-the-Universe, which is estimated to occur for the next 10^20-some-odd years.

After that, black holes the mass of the Sun will finally start to lose more energy due to Hawking radiation (on average) than they’ll absorb, completely evaporating after ~10^67 years, and with the largest black holes in the Universe disappearing after around ~10^100 years. That may be far longer than the age of the Universe, but it’s still not forever. And the way it will decay is through the mechanism of photon emission via Hawking radiation.

You might look at numbers like 10^10 years (the present age of the Universe) and think it’s not such a big leap to 10^20 years, but you’ve got to remember how orders of magnitude work. It takes ten times the present age of the Universe to get to 10^11 years; ten times that to get to 10^12 years, etc. You absorb one proton per 10^20 years, and you’ll grow faster than you shrink due to Hawking radiation. No one’s decaying anytime soon.

Image credit: XMM-Newton, ESA, NASA.

Image credit: XMM-Newton, ESA, NASA.

From Michael Kelsey (again!) on the black hole conference wrapping up today: “@Ethan and/or @Sabine: Do either of you know if the talks at the HR Conference are going to be posted to the program (http://global.unc.edu/hawking-radiation-conference-program/)?”

Hawking’s talk is available in an embedded video here (it’s short), and it looks like there was a live feed of the other talks, as there’s photographic evidence on the Nordita facebook page of Malcolm Perry’s talk:

Image credit: Nordita live feed, via https://www.facebook.com/nordita.stockholm.

Image credit: Nordita live feed, via https://www.facebook.com/nordita.stockholm.

But as far as I know, there aren’t any permanent ways to view the lectures. Too bad, because much like you, Michael, I’d like to see them too! Guess we’ll have to wait until the Hawking/Perry/Strominger paper comes out, which I’m betting isn’t going to live up to the hype.

Image credit: Nicolas George.

Image credit: Nicolas George.

And finally, from MandoZink on the follow-up to the above picture of liquid nitrogen: “A photo from this same event, also credited to Nicolas George, is on Wikipedia’s “Liquid nitrogen” page. Hands possibly acquiring brown spots. Must be seconds later in sequence. Probably solid and sitting on (or stuck to) a shelf a few moment after that.”

Because the internet is amazing, I was able to find that picture and ID those brown spots right away. Have a look for yourself (emphasis mine).

Image credit: Nicholas George.

Image credit: Nicolas George.

I have done this to myself, by the way: given myself a cold burn with liquid nitrogen. I do not recommend it, and I do instead strongly recommend wearing the proper safety/protective equipment when you do any sort of work.

You only get one body, and having worked for an experimental physicist with fewer than ten fingers (who lost what he lost while taking a risk during his day job), I cannot emphasize the importance of basic safety awareness. You get one life; don’t let your impatience cost you the highest quality one you can have.

Thanks for the great week, looking forward to the next one, and if you’re my Patron on Patreon, can’t wait to deliver your rewards to you!

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Source: Phy Science blog

Physics Week in Review: August 29, 2015

Start your weekend with some data-driven eye candy. Artists Turn Tectonic Activity Into Surprisingly Soothing Data Visualizations with Bloom. “The horizontal position of each of the blooms is based on time, while its vertical position is based on the magnitude of the rate of change of motion detected at the seismograph. Large tectonic tremors create big blooms, small jitters are tiny buds.” Stephen Hawking made headlines yet again when he gave a talk this week at a Nordita (Nordic Institute for Theoretical Physics) conference (held at KTH Royal Institute of Technology in Switzerland to better accommodate his accessibility needs) exploring his black hole information paradox, announcing that he had solved the mystery. Eureka! Specifically, he has figured out a possible mechanism for how information might eventually escape (sort of) a black hole. (The Backreaction blog was there live-tweeting the discussion.) He’s building on prior work positing that the information isn’t destroyed, but rather gets encoded in some kind of structure at the event horizon, and is then carried out with the Hawking radiation as the black hole evaporates. To wit: “The information is stored in a super translation of the horizon that the ingoing particles [from the source star] cause,” Hawking explained. “The information about ingoing particles is returned, but in a chaotic and useless form. For all practical purposes the info is lost.” Alternatively, it may emerge into another universe.
Ah, but not so fast: he’s still working out the devilish details with collaborator Andrew Strominger of Harvard. And while Hawking says that paper will be ready by the end of September, Strominger told the Los Angeles Times they’re nowhere near done working on it, adding, “Stephen is very optimistic that it’s all going to work perfectly. But physics is a hard mistress. You have to get all the calculations to work perfectly and everything has to line up.” It’s also worth remembering that Hawking is not the only physicist to have claimed to have solved the information paradox in recent years. A cautious observer would conclude, as Scientific American did, that Hawking’s not quite solved it yet, because  the mystery of black holes and information loss is too thorny for a quick resolution.
I’ve covered this topic extensively for Quanta: see here (firewalls) and here (fuzzballs), as well as this piece by K.C. Cole. Related: Medium’s Ethan Siegel offers a handy backgrounder on Ten Things You Should Know About Black Holes. And what makes them different — or not so different— from everything else in the Universe.  Also: Physicist Robert McNees Storified his series of 20 tweets on black hole entropy, for your reading pleasure.
The Shadow of a Black Hole. “Event Horizon Telescope astronomers have already achieved resolutions nearly good enough to see the event horizon of the black hole at the center of the Milky Way. With the upgrades and addition of more telescopes in the near future, the EHT should be able to see if the event horizon size corresponds to what general relativity predicts.”
New Experiment Closes Quantum Loopholes, Confirms Spookiness.
How quantum biology might explain life’s biggest questions.  “How does a robin know to fly south? The answer might be weirder than you think: Quantum physics may be involved. Jim Al-Khalili rounds up the extremely new, extremely strange world of quantum biology, where something Einstein once called ‘spooky action at a distance’ helps birds navigate, and quantum effects might explain the origin of life itself.”
A New Energy Plant In Hawaii Generates Power From Ocean Temperature Extremes.”There’s a big [temperature] difference between the warm, shallow seawater lapping up against a beach and the icy depths of the ocean.” And that means energy can be harnessed for useful work. Yay, physics!
How Quantum Pachinko Makes Solid Matter Possible. Dividing the universe into fermions and bosons might seem arcane and arbitrary, but without that weird quantum rule, our macroscopic world could not exist.
A little light interaction leaves quantum physicists beaming. They “have taken a step toward making the essential building block of quantum computers out of pure light: h a specific part of computer circuitry known as a logic gate.”
How do you go about embracing complexity? It’s complicated (duh!), but two physicists offer a set of principles for where to start.
L is for LIDAR, a laser tool whose uses include scanning objects for cinematic special effects. “We’ve scanned horses. We’ve scanned dogs. The beauty of working in film is that one day we can be scanning a Roman villa, and that evening be scanning the set of some futuristic robot movie.”  For more about LIDAR, see my own 2012 post.
High-Tech Tools Used to Understand Medieval Manuscripts. “Fragile pieces of parchment can be difficult to study because of their age, rarity and susceptibility to contamination. Researchers at the Norwegian University of Science and Technology’s Gunnerus Library are developing new high-tech tools to unlock the secrets hidden in old parchment.”
How That Spinning Spacecraft From The Martian Would Work for Artificial Gravity.
The Science And Fiction Behind Blade Runner, still widely regarded as one of the best science fiction films ever made.
The story of how a guitar got to the Space Station: A Larrivee Parlour floats weightless there. Astronaut Chris Hadfield visits Larrivée Guitar factory and talks about playing guitar in space.
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Spiders Tune Their Webs Like Guitars. “How does a spider tell a potential meal from a potential mate? The answer lies in the vibrations of its finely-tuned web.” Resonances for the win!
Looking for strings inside inflation. Theorists from the Institute for Advanced Study have proposed a way forward in the quest to test string theory.
Would a Falling Drone Crush Your Skull? The fine folks at Motherboard Did the Math.
Who’ll Freeze First? A Puzzle About Size and Staying Warm. 
How long does it take an electron to tunnel? The attoclock provides a unique window into quantum tunneling dynamics.
Scientists explore the origins of energy in chemical reactions using experimental quantum chemistry.
The Courage to Venture Beyond: Of Polymaths and Multidisciplinarians.
Engineers unexpectedly discover new type of glass. “What we have done is to demonstrate that one can create glasses where there is some well-defined organization. And now that we understand the origin of such effects, we can try to control that organization by manipulating the way we prepare these glasses.”
Surfing Antimatter: Accelerating positrons with plasma is a step toward smaller, cheaper particle colliders.
Massachusetts parents cite shaky science in lawsuit over Wi-Fi network. Claim their child is harmed due to “Electromagnetic Hypersensitivity Syndrome.” This is totally not a thing: studies show that “people who claim to have the disorder simply can’t tell whether equipment that emits this radiation is switched on or not.”
Capture sunlight with your quantum dot window. A luminescent solar concentrator is an emerging sunlight harvesting technology that has the potential to disrupt the way we think about energy.
Hydrophobic sand turns to goo in water and magically turns back to sand when dry.
Quantum Political Scientists Hypothesize Country Headed In Both Right And Wrong Directions Simultaneously. “Rather than inhabiting a single reality where the nation’s future looks bright or an opposite one where Americans are struggling like never before, our research suggests that these two conditions actually exist concurrently in a state of superposition.” When, oh when, will the wave function collapse and rid us of this blasted superposition?
21 Reasons Why I Hate Math by slam poet Shappy Seasholtz. “19: Math made Russell Crowe go crazy in that one movie.”
Why the Poohsticks formula is wrong: The equation is just a collection of sciency-looking symbols.
What NASA Calls Microgravity is Really Freefall. “Astronauts and everything else that isn’t tied down on the ISS appear to float about not because they are in “microgravity” or even small gravity (as NASA prefers to define micro). Nor are they floating about because they are “weightless.” They aren’t actually floating at all. They are falling.”
Motherboard reports from a conference of space elevator enthusiasts. So naturally the takeaway is: Space Elevators Are Totally Possible (If Someone Will Just Pay for It). “This would of course all go a lot faster if we had, you know, money.” Um, no — the technical challenges are truly daunting and will require more than big wads of cash. See my own take on space elevators from April.
Labyrhythms, a sound art piece by David Harris (artist in residence at TRIUMF in Vancouver, and new editor of the Facts So Romantic Blog at Nautilus), is based on scientists reading abstracts of their papers.  Also: Journey to the Heart of TRIUMF: A Narrative in Silences, “explores the little noticed “silences” of the spaces in which scientists work. It is a collection of room tone and ambiance mixed together to represent a journey into the heart of the lab where the main cyclotron lives.”
The cool science behind how the Lexus hoverboard: works
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It Takes 26 Fundamental Constants To Give Us Our Universe, But They Still Don’t Give Everything.
The Geology Of Star Trek: From Extraterrestrial Minerals To Alien Life-Forms. “You must be one with the rock.” – Spock to Kirk in Star Trek V
New Sugar Substitute: Nanoparticles Of Sand Coated In Sugar. Related: When Size Matters: Big questions about risk assessment of nanomaterials.
Time Travel To-Do List: “1. Locate/build time machine.”
No, Da Vinci Wasn’t The First Inventor to Dream About Human Flight. List includes my personal fave, Eilmer of Malmesbury, circa 1125 AD.
Clever! Teach kids chemistry with this DIY Periodic Table Battleship.
3M Creates Scientific Rube Goldberg Machine with Own Products. “There are some awesome bits of science at work here, like the fluid mechanics of a ball floating on an air jet.”
It’s Easier To Tell Time Than do Math on This Slide Rule Watch.
2015 Nobel Prizes October Madness: Pick your faves in physics, chemistry, and physiology/medicine.
Take an Epic Quest across a Hyperbolic Surface. David Madore’s online mazes let you explore complicated hyperbolic surfaces from the comfort of your favorite web browser.
Of Pi and Tau: “[Michael] Hartl makes a compelling case for the idea that 2π, the ratio of a circle’s circumference to its radius, is a far more fundamentally significant and useful construct. He calls his new ‘circle constant’ tau.”
Scientific Revolutions in Optics Made Vermeer a Revolutionary Painter.
LISA Pathfinder to Refine Hunt for Gravitational Waves.
Revealed: how a wobbly axis helped our planet escape ‘snowball Earth.’
Fire tornadoes, despite their name, are more closely related to dust devils or waterspouts than to true tornadoes. Here’s more about fire tornadoes from the Bad Astronomer.
How Fast Are We Moving Through Space? According to relativity, there’s no universal frame of reference. But the Big Bang gave us one anyway. Related: Here’s How Ludicrously Fast A Space Probe Is.
Misusing Galileo to criticise the Galileo gambit.
“Supersonic” (2014), Oil and linen, 72 x 54 inchesn. Credit: Michael Kagen
Michael Kagen’s Space-Based Paintings (above) Explore the Fatalistic Power of Manmade Machinery. “Kagen exhibited this series of space-based paintings last year at Joshua Liner Gallery in an exhibition titled Thunder in the Distance. He was also recently commissioned by The Smithsonian to create three large paintings inspired by their air and space archives.”
US astronauts drink recycled urine aboard space station but Russians refuse.   “It tastes like bottled water,” Layne Carter, water subsystem manager for the ISS at NASA’s Marshall Space Flight Center told Bloomberg. “As long as you can psychologically get past the point that it’s recycled urine and condensate that comes out of the air.” Related: Japan Delivered Whiskey to Space Station on Monday — for Science. And maybe for the Russians refusing to drink recycled pee. Kanpai! Except maybe not. Even Without Gravity They Can’t Raise A Glass.
Meet the Woman Who Discovered the Composition of the Stars. When she first finished her revolutionary thesis, Cecilia Payne was told that the results were “clearly impossible.”
Five classic American books that inspired Susan Helms in her career as an astronaut.
Carbon Monoxide ‘Fire Fountains’ Erupted on the Moon.
How SETI Will Understand Messages Broadcast by an Alien Intelligence.
No, a giant asteroid won’t hit the Earth in September. It’s BS: Bad Science. Related (kinda): We now understand the Universe’s doom better than ever.
The Huge, Pricey Detectors That Capture Tiny Neutrinos: IceCube, NoVA and more.
Vapor cones typically appear around aircraft flying in the transonic regime –- near, but still below, the speed of sound.
Secretive fusion company claims reactor breakthrough. Caveat: It’s a Startup With No Website. Related: How Close Are We To Nuclear Fusion? “Naysayers love to claim that nuclear fusion is always decades away — and always will be — but the reality is we’ve moved ever closer to the breakeven point and solved a large number of technical challenges over the past twenty years.”
Recently found in American backyards (specifically, Missouri’s St. Louis County): radioactive nuclear waste (thorium 230) from the Manhattan Project.
Q: What Would Happen If You Dropped A Nuclear Bomb Into A Volcano? A: Nothing, actually. “The bomb would melt without starting a nuclear reaction.”
The geometry of Islamic art.
The Science Behind Antarctica’s Blood Falls: Iron-rich brine from a subglacial lake accounts for Blood Falls’ creepy crimson hue.
In science we trust… up to a point. “Science is emphatically not a belief system.”
How to Tell Science Stories with Maps. “Maps are some of the most information-dense ways of communicating data,” says Len De Groot, director of data visualization at the Los Angeles Times. … “You can do a lot in a map because people already understand the fundamentals—unlike, say, a scatterplot.”
Q&A: How the Franco dictatorship destroyed Spanish science. 
Lab coats and leggings: when science and dance connect it’s quite a show. “Initiated in 2013 by Liz Lea and Cris Kennedy at CSIRO in Canberra, the DANscienCE Festival provides a platform for delving into how dance can be help scientists understand more about brain function and how our bodies respond to movement. It also examines how dance can serve as a powerful teaching tool for helping those outside academia understand sophisticated academic ideas.”
“Waiter, there’s a tiny boat in my martini…” A “Cocktail Boat” Can Propel Itself Around Your Drink Using the Marangoni Effect.
The Physics Girl Explains How to Make a Cloud in Your Mouth. “you’ll need to make tiny water droplets in your mouth. Then up the pressure.” Related: How To Make a Hurricane on a Bubble. Per IFL Science: “A team from the University of Bordeaux managed to mimic the physics of a hurricane on a bubble, and subsequently recreated the behavior of hurricanes and cyclones in our atmosphere.”
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How Does a Gymnast–Or Even a Fitness Walker–Keep From Falling?

Kathleeen Cullen jokes that when she was studying electrical engineering at Brown University during the 1980s, she heard a rumor that neurons use electricity. That prompted her to take a course on the brain that convinced her to major in neuroscience as well as electrical engineering. Cullen arrived at the University of Chicago—and later at McGill for a postdoc—at a time that researchers were starting to explore how neurons in the brain react to inputs from the senses when making voluntary movements. Many earlier observations were conducted by looking at the activity of the cells in stationary animals.In the ensuing years, Cullen’s work as a professor at McGill has specialized in studying the vestibular system that allows us to maintain our balance. Cullen has retained a fasciation with the vestibular system because of its elegant simplicity. Vestibular neurons both receive sensory input and send commands to peripheral nerves to initiate movement. In recent weeks, Cullen and colleagues published a paper online  in Nature Neuroscience that demonstrates how the calculations individual neurons make in a part of the brain called the cerebellum—a region directly connected to the vestibular system—can perform the simple task of making sure our bodies are positioned where we want them to be in relation to our surroundings. Here’s an interview with Cullen, edited for clarity.
Scientific American: The paper begins with an interesting observation about how the brain allows us to acquire new skills in response to changes in the external environment. That seems still to be a major question in neuroscience that people are trying to come to grips with in various way.
I think so. A lot of people who are working in neuroscience are trying to understand the neural mechanisms of learning. You probably don’t think about it that often but even if you’re working on a tennis serve and you think you’ve got the movement down perfectly, your muscles are still changing. They’re fatiguing. You have to be updating your motor commands constantly in order to deal with the fact that your motor system is dynamic and changing over time. Put another way, because the  biomechanical properties of the motor system constantly change over time we need to keep its systems calibrated.
You seem to be getting down to some of the fine details of how the motor system works at a very elemental level. So it would be good to talk about how researchers approached things previously before going on to describe what you found.
Using a combination of behavioral and theoretical approaches, people have speculated that when you move, your brain keeps track in real time of how you’re actually moving vs. how you intended to move in order to appropriately update and adjust your movements. We know that the intrinsic delays of feedback from sensory signals are too slow. Instead, our brains need to calculate in real time any errors in order to accomplish motor learning.
Studies in which researchers experimentally perturbed voluntary movements had suggested that our brains ensure accurate motion by computing sensory prediction errors. The sensory prediction error is the difference between the sensory inflow your brain is expecting if you generate a movement vs. the actual sensory inflow it pulls in. The proposal had been that the brain can compare these two quantities very quickly to compute a sensory prediction error signal immediately during voluntary movement.
What would be an example of a sensory prediction error?
Imagine a gymnast doing a back flip on a balance beam. The gymnast has done this many times and has a great appreciation, an internal model of exactly the type of sensory inflow he or she should be getting from the vestibular system, which lets one know about their three-dimensional motion through space, as well as input from the proprioceptor receptors, which provide feedback from different muscles to also give a sense of body motion.
The body’s internal model compares its expectations based on having done something before to what it’s actually pulling in from its sensory receptors. When there’s a small error, that error may be because you lost your balance a little bit or it could be because you’re in a slightly different motor state than you had been when initiating some motion. So you need to recalibrate. We had a paper in the journal Current Biology that preceded this one in Nature Neuroscience, which showed that the cerebellum computes this sensory prediction error to help you maintain balance by computing this error signal.
What we’ve shown in this second paper in Nature Neuroscience is that when you have a persistent error – specifically a persistent unexpected sensory error, your brain actually learns and we can watch it learn trial by trial by trial. That’s what you should expect to happen so that’s why we called the paper ‘Learning to Expect the Unexpected’. Strikingly, as the brain learns to update its internal model of what to expect, we can actually watch this updating in real time by recording from single cerebellar output neurons.
What is important about recording from single neurons?
Researchers like me, systems neuroscientists who often also trained as engineers or physicists, like to compute these quantities that, in a mathematical sense, explain how the brain actually does something. This is all good and fine for describing a theoretical way in which the brain may be doing something. But the most important question remains—is the brain really performing the computation in this way and if so how would this look? So what we’ve actually found a neural correlate for these little black boxes that we draw to illustrate our theories. To see that this is actually the way that these neurons are performing computations is very exciting. Basically, in our work we have been able to very cleanly bridge the gap between the computational methods that have been applied to solving the problem using engineering approaches and actual reality. We discovered that the brain does indeed perform this sort of elegant math. The fact that we can see this manifested at the level of single neurons lets us know that the brain is actually using a particular algorithm.
Does the brain do it the way you expected it do it?
There has been some evidence that the cerebellar cortex (the surface of the cerebellum) is involved in developing this internal model of the expected sensory consequences. The cerebellar cortex is a network of cells that has a very beautiful and almost crystalline structure. Cerebellar damage does not cause paralysis, but instead produces disorders in fine movement, equilibrium, posture, and motor learning.  Researchers now have good evidence that the cerebellum is involved in encoding signals consistent with what is called a forward model. This is an idea that’s been developing considerable support over the last decade. What people hadn’t demonstrated before this study was the actual computation of this error signal. This demonstration is important for most current models of motor learning. That’s what we’ve demonstrated at the level of neurons that get direct cerebellar input. We took advantage of a particular pathway where the Purkinje cells in the cerebellar cortex project directly to a specific region of the deep cerebellar nuclei. The deep cerebellar nuclei are effectively located at the base of the ‘cauliflower shaped’ cerebellar cortex – and this is where we recorded from a small group of cells, within a subdivision of the cerebellar nuclei called the rostral fastigial nucleus.
The fastigial nucleus is a sphere that’s maybe a millimeter in radius and contains neurons that are very interesting because they connect the cerebellar cortex to the spinal cord and are vital for postural and head movement control. One of the really interesting things we found is that we can see the response of these neurons beautifully tracking the comparison between predictive and actual sensory feedback systems during voluntary motion.
How did you do the experiment?
We carried out a trial-by-trial analysis of cerebellar neurons during the execution and adaptation of voluntary head movements and found that neuronal sensitivities dynamically tracked the comparison of predictive and feedback signals. (The extent that a neuron is activated by a particular input is known as its sensitivity.) When the relationship between the motor command and resultant movement was altered, neurons robustly responded to sensory input as if the movement was externally generated. Neuronal sensitivities then declined with the same time course as the concurrent behavioral learning. These findings provide direct evidence for an elegant computation requiring the comparison of predicted and actual sensory feedback to signal unexpected sensation.
 Were any of these findings a surprise?
People have been studying behaviors like reaching which are quite complex. Because we were looking at a relatively simple sensory motor pathway that controls head motion, we were able to see this computation very cleanly. You can say maybe it was expected based on computational models, but there are many models that people have built of the brain in neuroscience that cannot be directly compared to actual neuronal responses and circuits. It’s often not possible to directly correlate any sort of actual neuronal properties with the models. That the link we found is so explicit is to me quite exciting.
How does your work relate to that of others in the field?
There are currently researchers at a number of institutions, including Johns Hopkins in Baltimore and Ludwig Maximilian University in Munich, who are using computational modeling to understand deficits in patients with damage to the cerebellum. If you look at these patients, their disabilities are consistent with an inability to calculate sensory prediction errors. By Occam’s Razor, it would appear that this computation should exist but again these sorts of computation could exist and not be evident using current techniques. So it’s exciting that we can see this playing out in real time using conventional single-unit electrophysiology. I don’t think people would have guessed that we would see it so clearly.
What next experiments does this work suggest?
It’s one thing to show the computation has occurred. It’s like a smoking gun in a way but we’d now like to understand how the brain actually accomplishes this computation. Our research demonstrates that the cerebellum actually computes unexpected motion within milliseconds so that we can send an appropriate signal to the spinal cord to rapidly adjust our balance and learn new motor skills. By understanding how this computation is accomplished, we can develop better approaches for treating patients and can potentially also translate this knowledge to advance new technologies, such as improving how robots move and perform.
What about potential clinical implications?
If we understand the computations that the cerebellum is doing, then we have an opportunity to understand what happens in patients with loss of cerebellar function – for example, following stroke or in brain disorders such as multiple sclerosis. In addition, this knowledge can lead to the design of better, more effective, protocols for rehabilitation or even for sports training of athletes.
It’s particularly important to continue developing and improving rehabilitation programs because at the moment, it can be a bit of the Wild West. Health professionals do what they think is best for the patient, but we do not yet fully understand how to optimize training and exercises. But by being a little more systematic so that we take advantage of the brain’s own computational algorithms, we might get much better outcomes in the future.
(In the interview, Cullen emphasized that her two postdoctoral fellows, Jessica X. Brooks and Jerome Carriot, were essential collaborators in conducting the study on sensory prediction errors.)

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Ask Ethan #103: Have We Solved The Black Hole Information Paradox? (Synopsis) [Starts With A Bang]

“Thus it seems Einstein was doubly wrong when he said, God does not play dice. Not only does God definitely play dice, but He sometimes confuses us by throwing them where they can’t be seen.” –Stephen Hawking

You’ve no doubt heard that Stephen Hawking is claiming that the black hole information paradox has now been resolved, with the information encoded on the event horizon and then onto the outgoing radiation via a new mechanism that he’ll detail in a paper due out next month, along with collaborators Malcom Perry and Andrew Strominger.

Image credit: TU Wien.

Image credit: TU Wien.

Only, that’s not really what’s happening here. While he does have a new idea and there is a paper coming out, its contents do not solve the information paradox, but merely provide a hypothesis as to how it may be solved in the future.

Image credit:  Dr. Rubens C. Reis, via http://dept.astro.lsa.umich.edu/~rdosreis/rreis/Home.html.

Image credit: 
Dr. Rubens C. Reis, via http://dept.astro.lsa.umich.edu/~rdosreis/rreis/Home.html.

Come get all the available details here on this edition of Ask Ethan.

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Source: Phy Science blog

Change Your Open Sets, Change Your Life

When I started writing about my favorite topological spaces, I knew I’d have to confront open sets someday. In topology, it’s not enough to define a space by saying what points are in it. Every topological space comes with baggage: open sets. There are only a few rules: the total space and the empty set both have to be open sets, the intersection of any finite number of open sets has to be open, and the union, or combination, of any collection of open sets has to be an open set as well. In some sense, all open sets are generalizations of an open interval like (0,1) on the number line. (If math notation is a distant memory, the parentheses here mean we include all the numbers greater than 0 and less than 1 but not 0 and 1 themselves. If we wanted to include the endpoints, we would write [0,1] and call it a closed interval.) In order for us to satisfy all the requirements above, we also declare that the empty set is an open set, as are unbounded intervals like the set of all numbers greater than 3, which we would write (3,∞), and that collections of open intervals are open.
But we could make different decisions about what sets are open and end up with a different topological space. One alternative to the standard topology is called the lower limit topology. In this topology, open sets are half-open intervals: [0,1), for example. The only difference is that we now include the left endpoint. When we analyze the rule that unions of open sets must be open, we discover that when we define sets like [0,1) to be open, we get sets like (0,1) as well. Thus the lower limit topology is definitely different from the standard topology: everything that is open in the standard topology is open in the lower limit topology, but the lower limit topology also has other open sets the standard topology doesn’t.
Why should we care about open sets? Far be it from me to tell you how to feel, but mathematicians care about open sets because they allow us to determine the properties of functions on very abstract spaces.
Discontinuity. Image: Alan Joyce, via Flickr.
The most important property of functions between spaces is continuity. Continuity is intuitively obvious for spaces like the number line (with the usual topology): a function is continuous if you can draw its graph without picking up your pencil. There are no big jumps anywhere.
The intuitive definition of continuity requires us to be able to measure the distance between points, but sometimes mathematicians want to be able to define continuity for functions between spaces that don’t necessarily have a built-in distance function. The topological definition of continuity only requires open sets. A function is continuous if the preimage of every open set is open. The preimage of a set is just the collection of points that are mapped to that set under the function. For example, if the function is f(x)=x2, the preimage of 1 is the union of the points 1 and -1.
To see the importance of open sets to continuity, let’s go back to the number line. The standard topology with open intervals as the open sets is just the beginning. With that topology, continuous functions are exactly what we expect: no big jumps. The easiest alternative topology is the indiscrete topology. In that one, we decide that the only open sets are the entire line and the empty set. After all, we’re busy people, and we’ve got other important things to do. Now let’s think about a function from the number line to itself with the indiscrete topology. No matter what the function is, we only care about the preimage of the entire line because that’s the only nontrivial open set. If the function is defined on the entire line, then the preimage of the line is the entire line, an open set. Therefore any function is continuous if the target space has the indiscrete topology.
The discrete topology, on the other hand, goes small. In this one, every individual point is an open set. The rules of open sets then declare that every combination of points is an open set. Although this is in some way the opposite of the indiscrete topology, it also has the effect of drastically simplifying the process of figuring out whether a function is continuous. If you have a function from the number line with the discrete topology, it doesn’t matter what the function or even target space is. The function will be continuous because there are no non-open sets in the discrete topology.
When students first encounter beginning topology, they are sometimes disoriented by the power they wield. Mathematical spaces don’t always come equipped with their open sets, so we get to define them by fiat. Of course, some open sets are more useful than others, but in the end, we are masters of our topological destinies.
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Piers Corbyn, his brother and communist weather forecaster [Stoat]

I’m back. Did you miss me? Don’t all say “no” at once.
A piece from the Torygraph about the unfolding disaster that is Jeremy Corbyn’s run for head of the Labour party; they can barely contain their glee, of course, but I did like the idea of someone forcasting communist weather; Boris, perhaps.

The still is, presumably deliberately, unfortunate; its from that video, isn’t it? The text includes

Piers, the eccentric weather forecaster brother of Corbyn… While the Labour leadership candidate may be considered to have a colourful record, his older brother can outdo him by a mile. He claims to be able to predict the weather accurately by up to a year in advance. He also claims that earthquakes can be caused by the sun’s activity and he is a staunch climate change denier.

I’m sure PC is delighted with that. Meanwhile, for those wondering, I’ve been off in the Stubai again, this time in company. Here’s the start of a particularly fine day, looking back to the Mullerhutte and Beckerhaus from the Wilder Pfaff.

Refs
* US Gun Violence: So Bad, All That’s Left Is a Joke – QS* CIP – still talking to the nutters* Speaking of nutters, Sou has the remarkable story of Singer self-identifying as one; weird or what. He’s very old now, indeed he has been for a decade, and shouldn’t be let out alone* ATTP notes the sad end of the Met Office’s Wx contract with the Beeb
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