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Spotlight: On July 5, the NASA probe Juno got into orbit around Jupiter after what has been hailed as an especially difficult orbital insertion manoeuvre. The probe had to slow down enough for Jupiter’s gravity to ensnare it in an orbit. It had to move in such a trajectory that kept it shielded from the strong radiation surrounding the planet, especially near its poles. And it had to steer clear of the planet’s dozens of moons and other orbiting debris. All of this meant there was an effective 35-minute window within which Juno had to get into a ‘correct’ orbit around Jupiter, and it missed its mark by no more than a second. Fabulous.
All said, some fact-checking was due, and historian Thony Christie did it best. In a post on his blog, he spoke about the nomenclatural provenance of the so-called Galilean moons. These are the four largest moons of Jupiter: Io, Europa, Ganymede and Callisto. They were discovered by Galileo Galilei in early 1610, supposedly a day before another astronomer, Simon Marius, did. However, Galileo didn’t give those names to the moons. That was the work of another genius:
In the Mundus Iovialis Marius makes several naming suggestions. His first suggestion is to just number the moons I to IV, a system that was actually used by astronomers. His second suggestion follows Galileo in that he wishes to name them after his employer/patron the Margrave of Ansbach’s family and call them the Brandenberger Stars. Marius’ third suggestion is more than somewhat bizarre as he suggests naming them in analogy to the solar system planets, so the moon with the smallest orbit would be the Jupiter Mercury, the next the Jupiter Venus, the third the Jupiter Jupiter and the fourth the Jupiter Saturn. As I said bizarre. It is with Marius’ fourth suggestion that we finally arrive at Zeus’ lovers. … In the next paragraph Marius goes on to explain that the idea for using these names for the moons was suggested to him by Johannes Kepler when the two of them met at the Imperial Parliament in Regensburg in October 1613. He then names Kepler as co-godfather of these four stars.
Happy (belated) birthday, Nikola Tesla!
July 10, 1856 – January 7, 1943
Jonah Lehrer & unoriginality
Jonah Lehrer can’t catch a break. He’d been intellectually excommunicated in 2012 after it was found that he had plagiarised, self-plagiarised and fabricated widely in his books and articles for The New Yorker and Wired. All his deals and contracts fell through, leaving the writer, once celebrated for his commentaries on neuroscience, desperately seeking a fresh start. And that start is a pithy book pithily called A Book About Love. Actually, ‘pithy’ might be a gross understatement if Jennifer Senior’s review in the New York Times is to be believed. It’s a schooling in scathing writing if nothing else.
In retrospect — and I am hardly the first person to point this out — the vote to excommunicate Mr. Lehrer was as much about the product he was peddling as the professional transgressions he was committing. It was a referendum on a certain genre of canned, cocktail-party social science, one that traffics in bespoke platitudes for the middlebrow and rehearses the same studies without saying something new. …
There’s a lot of dime-store counsel in this book, often followed by academic citations. It’s like reading an advice column by way of JSTOR.
To the extent that he has one, Mr. Lehrer’s argument is that humans crave connection. He borrows heavily from attachment theory to explain how we approach relationships. We seek secure attachments to our parents, to our spouses, even to God, the ultimate “secure base.” The more securely attached we are, the healthier and more productive we are. He then hurls one well-known study after another at us to build his case, which really never required much building.
At times, his book becomes such a dense plague of studies, I had no idea where Mr. Lehrer was heading. He devotes an entire subsection to the plasticity of our memories, noting how they alter every time we recall them. I fail to see how this relates to love, exactly. He says it’s because “if our memories never changed, then we might adapt to their pleasures.” But I suspect it’s really because Mr. Lehrer can phone this material in, having already riffed on it ad nauseam: In his first book, in a segment on Radiolab, in a number of blog posts and columns. It’s his secure base.
Rudolf Kálmán, RIP
Rudolf Kálmán passed away on July 2. You likely haven’t heard of him. I’d like to mark his death for just one thing, a something that he invented: the linear quadratic estimation algorithm, also known as the Kálmán filter. There many algorithms used with great effect in control theory, which, among other things, seeks to predict how dynamic systems will behave over time given some statistical rules. However, the Kálmán filter in particular was so impossibly elegant when it was developed in the 1960s that many thought it ought not to exist.
Elegance, or beauty in general, is an important aesthetic of science that science’s modern practice has become increasingly cognisant of. Its uncovering lies at the nexus of simplicity, efficiency and versatility. As the physicist Murray Gell-Mann has argued, elegant solutions are likelier to be right than inelegant ones. This is, in a sense, a more granular (and less argumentative) retelling of Occam’s Razor.
The Kálmán filter really scores in this sense. It is special in that signifies it a kind of complexity that’s different from a majority of what science explainers concern themselves with. For example, quantum mechanics is simpler not in the science of it but in the colloquialisation and metaphorisation of it. On the other hand, the Kálmán filter is simpler in the science of it; colloquially, it’s magic.
Lior Pachter, a computational biologist at Caltech, has a cool anecdote befitting the invention on his blog. If you want a breakdown of what it really does, here’s an excerpt from a longer piece (well worth your time) by Tim Babb of Pixar Animation Studios:
You can use a Kálmán filter in any place where you have uncertain information about some dynamic system, and you can make an educated guess about what the system is going to do next. Even if messy reality comes along and interferes with the clean motion you guessed about, the Kálmán filter will often do a very good job of figuring out what actually happened. And it can take advantage of correlations between crazy phenomena that you maybe wouldn’t have thought to exploit!
Kálmán filters are ideal for systems which are continuously changing. They have the advantage that they are light on memory (they don’t need to keep any history other than the previous state), and they are very fast, making them well suited for real time problems and embedded systems.
The math for implementing the Kálmán filter appears pretty scary and opaque in most places you find on Google. That’s a bad state of affairs, because the Kálmán filter is actually super simple and easy to understand if you look at it in the right way. Thus it makes a great article topic, and I will attempt to illuminate it with lots of clear, pretty pictures and colors. The prerequisites are simple; all you need is a basic understanding of probability and matrices.
If you’ve been following Sandhya Ramesh’s ambitious series for The Wire that charts the geomorphological history of Earth, you’re aware of the unheadwraparoundable immensity of the geological timescale (the next instalment of the series is out today). In the face of this spatiotemporal expanse, the only way to comprehend anything at all is to understand our own transience. Then again, mercifully, there will come along the rare opportunity where the bigness of our natural history is rubbing shoulders with the smallness of our human existence.
One such thing is a curb in the San Francisco Bay Area that straddles the Hayward fault, a 120-km long geologic fault. It merges with the Calaveras fault near San Jose at points 6.4 km underground. As the Hayward fault slowly moved, by about 4 mm/year, the curb that sits atop it became gradually misaligned with the rest of its pavement. Recently, city planners took notice and decided to ‘fix’ it. The result, as the LA Times put it:
By doing what cities are supposed to do – fixing streets – the city’s action stunned scientists, who said a wonderful curbside laboratory for studying earthquakes was destroyed.
According to Andrew Alden, a geologist, the soon-to-be-fixed curb will become iconic like its predecessor in about two decades. And as he went on to write on his blog,
There’s always the Old City Hall, too, which was built directly on the fault and has long been abandoned. The first time I visited there, maybe 25 years ago, I was looking at the street adjacent to it. As I watched, a little tongue of water emerged in the center of the street and started trickling downhill. Assuming that an old iron water main had just cracked, I found a phone booth and alerted the city. Cleaning up after a creeping fault never ends.
After the excitement of the Juno orbital insertion on July 5, Russia launched three astronauts to the International Space Station on July 6. While NASA missions are characterised by a charming effuseness and lots of social media hype and campaigns, Roscosmos launches are quiet and successful in an underrated way. NASA surely has been doing a lot more science, a lot more exciting science, and the difference in the amount of attention we pay to the achievements of each space agency can be attributed to that.
At the same time, as NASA jumps from big mission to big mission, it’s Russia that has been quietly ferrying astronauts to and from the ISS. In the July 5 iteration, three astronauts – one each from the US, Russia and Japan – were launched on board an upgraded Soyuz MS-01 rocket. From Space Policy Online:
The first Soyuz spacecraft was launched in 1967. It has been upgraded many times over the decades. Although the outer shell remains basically the same, the interior and its systems have changed with advances in technology. The most recent version was Soyuz TMA-M. The last of that type, Soyuz TMA-20M, is currently docked to the ISS ready to return its three-man crew to Earth in September: NASA’s Jeff Williams and Roscosmos’s Oleg Skripochka and Alexey Ovchinin.
Soyuz MS incorporates a number of changes: upgraded fully redundant thrusters, improved shielding against micrometeoroid orbital debris (MMOD), improved solar arrays yielding increased electrical power, redundant electrical motors for the docking probe, upgraded Kurs docking system with a phased array antenna that does not need to be retracted, improved satellite navigation system, improved communications through Russia’s Luch satellites, and a new digital video transmitter and encoder to provide engineering video of the spacecraft’s approach to ISS for docking.
PSA: In the last few days, I’ve noticed a lot of articles with headlines along the lines of ‘Has the LHC found a new particle?’ floating around the web. If the LHC has, you will only find out in August (3-10), during the International Conference on Higher Energy Physics. Most articles until then are likely only discussing the December 2015 announcement and the excitement in the particle physics community thereon.
Life on Titan
A new paper gets us into [the possibility of life on Saturn’s moon Titan] by suggesting that prebiotic chemistry — and possibly even biochemistry — could take place on Titan. The work of Martin Rahm and Jonathan Lunine, working with colleagues David Usher and David Shalloway (all at Cornell University), the study sees Titan as a ‘natural laboratory’ for exploring non-terrestrial prebiotic chemistry given the presence of liquid hydrocarbons and the lack of liquid surface water.
Titan is a fascinating moon. It’s larger than Mercury – and the only other object, apart from Earth, that we know has a dense atmosphere and liquid lakes on its surface. However, these lakes aren’t of water; liquid water is believed to exist scores of kilometres below its frozen crust. No, the lakes are of liquid methane and ethane. Its atmosphere is mostly nitrogen and methane, and so Titan in its entirety presents an altogether different kind of laboratory in which to explore the possibility of life’s emergence.
Research on this front has given rise to many hypotheses. Paul Gilster sums up the latest on his acclaimed superblog (from which the excerpt above was taken as well):
One of the polymers that may emerge from hydrogen cyanide’s reactions with other molecules is polyimine (pronounced poly–ee–meen), which is flexible even under the low temperatures found on Titan. The paper analyzes the properties of polyimine (pI) and finds that even in these conditions, it can absorb solar energy and become a factor in possible life. …
The polymorphism of polyimine compounds could be the key to prebiotic chemistry in the cryogenic conditions of Titan. The authors’ work on pI shows that complex, ordered structures can emerge. Moreover, polyimine is found to be able to absorb a wide range of photons through a relatively transparent ‘window’ in Titan’s atmosphere, thus having a source of energy at its disposal to catalyze prebiotic chemistry even without the presence of water.
Previous studies have hypothesised the existence of amene- and hydrogen-digesting microbes in Titan’s hydrocarbon lakes; asphalt guzzlers that need a tiny bit of water to get by; even live cells that have membranes of acrylonitrile azotosome (which could be present in Titan’s atmosphere) instead of the phospholipid bilayers that encase them on Earth. To further explore these possibilities, as well as explore Titan’s chemistry in general, NASA plans to drop a submarine into the moon’s largest hydrocarbon lake, Kraken Mare, around 2040. An excerpt from a piece I wrote in 2015:
[The author’s of the submarine’s design] continue: “The proposed ~1-tonne vehicle, with a radioisotope Stirling generator power source, would be delivered to splashdown circa 2040, to make a ~90-day, ~2,000 km voyage of exploration around the perimeter, and across the central depths of Kraken.” While its design is by no means final (it’s described as a “first cut”), that NASA is considering exploring Titan in great detail belies its interest in the moon as well as continued commitment to studying the Saturnian system in general. Note that the agency cancelled the development of the proposed Titan Mare Explorer – a nautical surface probe – soon after 2013 to channel the funds into developing Stirling radioisotope generators, which we now find could be used to power the submarine. …
Around 2040, they expect to be able to deliver it to Titan on board a ‘spaceplane carrier’, essentially a repurposed US Air Force DARPA X-37. According to them, Titan’s thick atmosphere could allow the carrier to descend to the surface at hypersonic speeds, following which attempt a soft-landing on the Kraken Mare. Finally, “the backshell covering the submarine would be jettisoned and the lifting body would sink, leaving the submarine floating to begin operations. (Alternatively, the submersible could be extracted in low level flight by parachute).”
Once inside, it will explore tidal currents in Kraken Mare, use a camera mounted on the mast to explore the shoreline landscape, make meteorological observations, analyze sediments from the seabed, and study trace organic compounds to learn how they evolved.
If only for the opportunities that Titan alone presents, we need to keep our hypotheses coming. Even Earth, with which we claim the most familiarity, surprises us with its hardy extremophiles (cases in point: Deinococcus radiodurans and Neosartorya fischeri). And if only to humble as well as amaze ourselves: I reproduce the following paragraph from a 2004 paper that neatly summarises the hope.
The universe of chemical possibilities is huge. For example, the number of different proteins 100 amino acids long, built from combinations of the natural 20 amino acids, is larger than the number of atoms in the cosmos. Life on Earth certainly did not have time to sample all possible sequences to find the best. What exists in modern [Earth-bound] life must therefore reflect some contingencies, chance events in history that led to one choice over another, whether or not the choice was optimal.
That’s it for this week. And do drop me a note about why you like or dislike (or both) Infinite in All Directions at [email protected] Cheers!