I will start writing actual blog posts again soon, I promise. But until then, more nerdy space stuff…
- ExoMars is approaching the Red Planet. The lander enters the atmosphere tomorrow.
The United States only operated continuous airborne alert — the maintenance of multiple nuclear-armed bomber aircraft continuously in flight to avoid the possibility of a sneak attack neutralizing the bomber force — during the ’60s, because the accident rate was too high. However, Operation Looking Glass kept at least one emergency command platform in the air around-the-clock for almost 30 years.
At DEFCON 2 or higher, the Looking Glass pilot and co-pilot were both required to wear an eye patch, retrieved from their Emergency War Order (EWO) kit. In the event of a surprise blinding flash from a nuclear detonation, the eye patch would prevent blindness in the covered eye, thus enabling them to see in at least one eye and continue flying. Later, the eye patch was replaced by goggles that would instantaneously turn opaque when exposed to a nuclear flash, then rapidly clear for normal vision.
- Very relatedly, former Secretary of Defense William Perry is teaching a MOOC about the continuing modern risk of nuclear weapons.
A history of the Project Orion. Abtract:
The race to the Moon dominated manned space flight during the 1960’s. and culminated in Project Apollo. which placed 12 humans on the Moon. Unbeknownst to the public at that time, several U.S. government agencies sponsored a project that could have conceivably placed 150 people on the Moon, and eventually sent crewed expeditions to Mars and the outer planets. These feats could have possibly been accomplished during the same period of time as Apollo. and for approximately the same cost. The project, code-named Orion, featured an extraordinary propulsion method known as Nuclear Pulse Propulsion. The concept is probably as radical today as It was at the dawn of the space age. However, its development appeared to be so promising that it was only by political and non-technical considerations that it was not used to extend humanity’s reach throughout the solar system and quite possibly to the stars. This paper discusses the rationale for nuclear pulse propulsion and presents a general history of the concept, focusing particularly on Project Orion. It describes some of the reexaminations being done in this area and discusses some of the new ideas that could mitigate many of the political and environmental issues associated with the concept.
The idea, of course, was to propel a spacecraft by dropping nuclear bombs out the back and riding a “push plate” that would absorb the blasts and transform them into continuous thrust. Not only was the design surprising immune to thermal damage to the absorbing plate, it actually worked in tests with chemical explosives:
Everything would be different:
Taylor and Francis de Hoffman, the founder of General Atomic, persuaded Freeman Dyson, a theoretical physicist at Princeton’s Institute for Advanced Study to come to San Diego to work on Orion during the 1958-1959 academic year. Taylor and Dyson were convinced that the approach to space flight being pursued by NASA was flawed. Chemical rockets, in their opinion, were very expensive, had very limited payloads, and were essentially useless for flights beyond the Moon. The Orion team aimed for a spaceship that was simple, rugged, roomy, and affordable…
Taylor and Dyson began developing plans for human exploration through much of the solar system. The original Orion design called for 2,000 pulse units, far more than the number necessary to attain Earth escape velocity. Their bold vision was evident in the motto embraced at the time, “Mars by 1965, Saturn by 1970.” One hundred and fifty people could have lived aboard in relative comfort, and the useful payload would have been measured in thousands of tonnes. Orion would have been built with the robusmess of a sea-going vessel, not requiring the excruciating weight-saving measures needed for chemically-propelled spacecraft.
- Picture of a cloud on Mars.
- Michael Brown, who discovered Eris and Sedna, predicts the existence of a planet several times Earth’s mass with a Sedna-like orbit. (Journal article.)
- The 2016 Comedy Wildlife Photography Awards.
- The city of Darwin, Australia (pop. 136k) has been devastated by several cyclones. In 1974, it was almost entirely leveled by Cyclone Tracy, leaving 41k of the 47k inhabitants homeless and necessitating the evacuation of 30k people from the remote northern Australian city.
- The hypothetical formation of black holes through intense focusing of light is Kugelblitz.
- An old idea: flood the Sahara Desert.
Ready to feel inadequate? Immanual Kant made deep insights about the structure of the Milky Way:
Actual proof of the Milky Way consisting of many stars came in 1610 when Galileo Galilei used a telescope to study the Milky Way and discovered that it is composed of a huge number of faint stars. In a treatise in 1755, Immanuel Kant, drawing on earlier work by Thomas Wright, speculated (correctly) that the Milky Way might be a rotating body of a huge number of stars, held together by gravitational forces akin to the Solar System but on much larger scales. The resulting disk of stars would be seen as a band on the sky from our perspective inside the disk. Kant also conjectured that some of the nebulae visible in the night sky might be separate “galaxies” themselves, similar to our own. Kant referred to both the Milky Way and the “extragalactic nebulae” as “island universes”, a term still current up to the 1930s.
The fact that many nebulae are galaxies distinct from our own was not settled conclusively until 1924.
Texture claims to be a simpler replacement for LaTeX, with more power than Markdown and less insanity than Word. At HN, capnrefsmmat emphasizes that this could help simplify the process of producing publication-quality documents, where JATS XML is the standard, and help cut out big publishers like Elsevier.
The scientific publishing workflow is insane, and this tool seems like it could help.
In the biomedical sciences (or any field that ends up on PubMed), articles have to be converted to JATS XML (http://jats.nlm.nih.gov/), a standard XML dialect for journal articles. It builds in citation metadata, cross-referencing, figure references, etc., and is supposed to be a stable archival format for long-term storage of articles. Individual publishers (PLOS, BMC, etc.) build their entire publication workflows around JATS, so articles can be typeset into PDF or rendered to HTML, or delivered to e-reader apps or whatever. Since it’s semantic XML, you can do bibliography mining, automatic reference following, extraction of figures, or whatever you might want to make reading or text-mining easier.
But articles are often written in Word, so there’s a tremendous amount of work going into manually or semi-manually converting every manuscript to semantic XML from the Word soup it arrives as. Same goes for LaTeX: a few journals just publish LaTeXed PDFs directly, but big publishers like Elsevier and Springer have semi-automated processes for converting LaTeX to in-house formats so they can provide HTML versions of pages.
So, short version: an editor supporting JATS XML can support all the features you need in a scientific document, and can dramatically simplify the publication workflow and hopefully save a bunch of money. And hopefully open-access journals pass that savings on to users.
For users, it could mean better e-reading apps (so you don’t have to zoom in on tiny fonts in a PDF on your iPad), better support for cross-referencing and figures than Word has, automated formatting (journals style the XML, so you don’t have to do margin and layout crap), and a simpler submission process.
- GiveWell is hiring a senior fellow to assess causal relationships in developing world health.
- In 1995, the Galileo Probe entered the Jovian atmosphere at an incredible 47.8 km/s. For comparison, low-Earth orbital speed is 7.8 km/s.
- The Alexander horned sphere.
A 1kW LED on a drone:
- It’s a shame that private, under-cover investigation of meat processors is necessary.
- Han unification looks…complicated.
- Tobias Osborne on QFT for quantum info theorists.
- XKCD on the subtle mistakes that can be made if you don’t think about lunar geometry. (More.)
Why the Hames Webb Space Telescope is infrared:
With adaptive optics, we are able to get images nearly as good as Hubble from the ground. So in the visible wavelengths, the next generation of telescopes are not moderately-sized space telescopes like Hubble, but enormous land-based optical telescopes, like the Thirty Metre Telescope or the European Extremely Large Telescope, which are under construction. These are the ones that will give you incredible high-resolution desktop pictures like this.
Putting things in space isn’t the best option for visible-light telescopes anymore, but it’s vitally important for wavelengths that are difficult to detect from Earth. Infrared radiation is difficult because its emitted by any material that’s even just a little bit warm, and so you get a huge amount of nonsense signal coming from all over the place, even if you set it up on the south pole or whatever. So there is a big advantage in putting an infrared telescope in space, where you can use cryogenics or a series of sun shields to keep it much cooler, and get a much clearer image. However, because infrared radiation has a longer wavelength than optical light, you get lower resolution with the same sized telescope. So while this will give us the highest resolution infrared images we’ve ever had, giving us a huge ability to map things like cold dust and gas and low-mass stars, it doesn’t really have a resolution that’s any better than Hubble’s optical resolution.
Some good /r/AskScience:
During hot weather, some lines of train track get “slow orders” prohibiting high-speed travel to keep the track from getting too hot and buckling due to thermal expansion. Similarly, track repairs made in cold weather are sometimes temporary and then replaced during temperate times to ensure the track isn’t placed under too much pressure in the summer.
The Milky Way has about 3 supernovae per century, but we haven’t seen one since 1604 because most are too obscured by dust near the center of the galaxy.
Here’s video of BlueOrigins testing their crew-escape system on the New Shepherd. (The escape system fires 44 seconds after launch.)
- List of largest cities throughout history. H/t Scott Alexander. Also from him: this overly optimistic and breathless, but still interesting, look at the state of Ethereum development.
- What does the Milky Way look like face-on? No one knows for sure, but here’s a good introduction to what’s known. More here and here.
initial operational capability declared for autonomous F-16s.
ACC assured that QF-16 is the introduction of fourth-generation fighter capabilities in the aerial target mission maintaining all capabilities of the baseline F-16 including supersonic flight and 9 G maneuverability….
Deputy Defense Secretary Robert Work has described it as a battle node network in line with the third offset strategy “where you take an F-16, make it totally unmanned — F-16 is a fourth-generation fighter – and pair it with an F-35 – a fifth-generation, what I would call battle network node — and those two operating together,” he said at a Washington Post event.
This concept can help navigate around anti-access/area denial environments, which aim to extend the range of adversarial forces and capabilities, by serving as a missile truck for fifth-generation fighters that are limited in their payload capability and accompanying them at high rates of speed currently unique vis-à-vis other unmanned platforms.
- Good discussion of all the stuff you get with the SpaceX lift capacity. Notably: a lunar space elevator.
- Uber offers unlimited UberPool in Manhattan (below 125th st) for a month for $200. Lunacy.
Metaculus is revamping their scoring rules:
You are still best off entering your best estimate of the outcome probability given all available information. Scoring is still based on a combination of being right, and also being more right than others, though you’ll see that in detail the numbers have changed a bit. What’s new is that your awarded points are a time-average of your point on-the-line at any given time, starting at question open and ending at question close. This means that you will maximize your points if: (1) You predict as early as possible, since your points on-the-line is zero until your first prediction, and (2) You update your prediction whenever you have reason to think your best estimate of the probability has changed. As before, you dial in your prediction using the slider, and you’ll see that points on-the-line change as you slide it. Once you make a prediction you will also see a “score history” tab that will show you how your points vary with time, in reflection of changes in your prediction, the community’s prediction, and the number of predictors.
Elon Musk announced the SpaceX Mars architecture:
Here’s the animation.
- First baby born with mitochondrial DNA donation. This is done by using a donor egg and replacing its nucleus with one from the mother’s egg. Makes me wonder how well they think they know all lines of inheritance. Is it possible that there are other inheritable traits encoded in the donor egg besides mitochondria? Maybe something that’s not even DNA/RNA? (Obviously a beginner question, but one that’s hard to find confident answers to without access to an expert.)
- Passing kidney stones using a roller coaster. If this works, there will be a billion dollar industry of human-being shaking machines covered by medicare.
William Bains and Dirk Schulze-Makuch argue that all the plausible chokepoints in Robin Hanson’s great filter actually show multiple historical repetitions, suggesting that none of them are particularly difficult, The only exceptions are the development of life itself and, for lack of decisive data, the technological rise of humanity.
[PDF.] This supports the hypothesis that I always felt was simplest and most likely: that abiogenesis is simply extremely, extremely rare/difficult, and this alone can explain the Fermi paradox. However, here’s Carl Shulman:
“Thus we postulate that the evolution of a genome in which the default expression status was “off” was the key, and unique, transition that allowed eukaryotes to evolve the complex systems that they show today, not the evolution of any of those control systems per se. Whether the evolution of a “default off” logic was a uniquely unlikely, Random Walk event or a probable, Many Paths, event is unclear at this point .”
My previous understanding had been that the origin of life, the emergence of eukaryotes, and possibly primate/human intelligence (insofar as it has ‘special sauce’ that octopi, elephants, crows, and similar lack) were the most plausible unique/filter events. This paper doesn’t much change that.
- Also in the Robin-Hanson universe, he addresses critics of his extensive application of social science to the em era. It’s fun to beat up on readers who want more narrative and less science, or who think their own intuition trumps years of data, but the last two critical quotes are not in these groups (and I’m not satisfied by Robin’s answers).
- Simons Foundation covers a recent initiative for an idea I’ve been championing (privately) for a long time: college instructors should give assign students to author and improve Wikipedia articles. There are so many things about this that make sense.
- There’s a commercial superconductor cable link between transformer stations in Germany.