An astronomy professor at the University of Leiden, Ignas Snellen,called brown dwarfs ‘failed stars‘ because they were too heavy to be typical planets (13-75 times as heavy as Jupiter) and too light to sustain the fusion of hydrogen into helium. As a result, they exist in a limbo in astronomers’ textbooks, with the precise mechanism of their formation remaining a mystery.
However, failed or no, brown dwarfs are still massive objects and make for interesting features in the universe. One stellar example is the pithily named J1407b. It was discovered in 2012 by astronomers at the Leiden Observatory and University of Rochester, New York, orbiting a star – J1407 – about 420 light-years from Earth. J1407b is young – about 16 million years old. But it’s most striking feature is an extended ring system.
In 2012, the astronomers studying it surmised that the dwarf likely has 37 rings, altogether 120 million km in diameter (as wide as Mercury’s orbit around the Sun). Compare this to Saturn’s ring system, which is at most 300,000 km wide*. There are conspicuous gaps between these rings as well – notably at a distance of about 60 million km from the inside – indicating that there might be moons inhabiting them, formed by sweeping up the missing material.
The research team estimates that the amount of material orbiting as rings might all together weigh as much as hundred-times Earth’s moon, which is not anomalous considering J1407b is still young and likely not fully formed yet.
The way it was discovered is interesting. An exoplanet shows itself when seen through a telescope when it passes in front of its host star and casts a weak but persistent shadow on the telescope lens. When observing the J1407 system using the Super Wide Angle Search for Planets project in 2007, the astronomers found something was taking 56 days to move all the way across the face of its star. It was either an extremely large object or it had rings.
A second observation supported the rings hypothesis: the amount of starlight blocked wasn’t constant, but rose and dipped as if the amount of material passing in front of it was uneven. In fact, at one point, fully 95% of the starlight was blocked.
“The star is much too far away to observe the rings directly, but we could make a detailed model based on the rapid brightness variations in the star light passing through the ring system,” noted Leiden’s Matthew Kenworthy, who analyzed the data. “If we could replace Saturn’s rings with the rings around J1407b, they would be easily visible at night and be many times larger than the full moon.”
Estimating the mass of the ring-system would’ve required Doppler spectroscopy data as well, which wasn’t available until late 2014.
Curiously, the planet J1407b hasn’t been spotted directly yet. The astronomers are assuming it’s there simply because something like it has to hold this ring system together. In fact, its characterization as a brown dwarf is simply what it has to be at the least. The Doppler data indicates it has to weight some 10-40 times as much as Jupiter, i.e. much bigger than a gas giant, much smaller than a main-sequence star.
A paper discussing the team’s results was accepted for publication in the Astrophysical Journal on December 28, 2014. Even as studies of this giant will continue, the astronomers have called on their amateur counterparts from around the world to help them. “J1407’s eclipses will allow us to study the physical and chemical properties of satellite-spawning circumplanetary disks,” Kenworthy said of incentives.
Fascinating things are happening to the world’s most-watched comet, 67P/Churyumov-Gerasimenko, as it approaches the Sun. A new study from NASA and ESA scientists published in Naturereports that by January 20, 67P shed a crust of dust built up on its surface over the last four years. In fact, by the end of January – about a week from now – the study’s authors expect heat and other radiation from the Sun will strip off the comet’s crust and mantle, exposing the icy nucleus.
As the comet hurtles into increasingly warmer space, the nucleus will start to evaporate into a dull haze around it that progressively forms the iconic tail as the ambient temperature increases. On August 13, 2015, 67P is expected to achieve perihelion, its closest distance from the Sun, at 185.98 million km.
The expelled dust was collected and analyzed by the ESA Rosetta probe that is tracking the comet, specifically by its Cometary Secondary Ion Mass Analyzer. It was found to be porous and rich in sodium, indicating that it may be the origin of particulate grains often found floating in the space between planets in the Solar System. The dust’s composition also challenges older notions that such grains are dominated by silicates.
Losing the dust
The deceptively simple process of shedding dust tells astronomers a lot about the comet’s composition and how it will change over time. The comet needs to be at a particular distance from a star for stellar radiation to whip away the dust from the surface. Therefore, based on the comet’s route from the Oort Cloud and toward the center of the Solar System, astronomers can deduce under what conditions the dust was accumulated to begin with.
As the dust builds up on the surface, it forms more and more layers devoid of icy particles borrowed from the comet’s nucleus. And as the whole comet heats up, the layers at the bottom start to vaporize first and unsettle the dust from the upper layers into a haze, called the coma, around it. Moreover, dust from the lower layers also starts getting floated toward the surface as a result of the icy grains started to melt. The overall effect – as the comet approaches the Sun – is for the coma to grow larger even as dust from the lower layers replenishes the coating on the surface.
At one point, however, the strength of the Sun’s radiation becomes strong enough to expel dust faster than it can be replenished – which is what is happening to 67P at the moment (Curiously, data from various instruments shows that the ‘neck’ region of this duck-shaped comet is losing dust the fastest).
The transition from when the replenishing mechanism is active to when dust is only getting expelled is usually smooth. Sometimes, however, it can be violent if there is a hard, intervening layer between the dust and the nucleus. Such a layer could be present on 67P, too, as evinced by the fact that the Rosetta probe’s lander Philae bounced around a bit on the comet’s surface on November 12, 2014, before it could latch itself on.
In all this time, two other instruments on board Rosetta, the Microwave Instrument for Rosetta Orbiter and Rosetta Orbiter Spectrometer for Ion and Neutral Analysis, have also been studying how the rates at which the cometary water vapor and other gases – such as carbon dioxide and carbon monoxide – being released from the nucleus vary. They have together found that while water vapor dominates the contents of the expelled matter, there are occasional spikes in the quantity of the two gases, too.
Myrtha Hässig, a NASA-sponsored scientist from the Southwest Research Institute, San Antonio, said, “This variation could be a temperature effect or a seasonal effect, or it could point to the possibility of comet migrations in the early solar system.”
Such conclusions, from the characteristics of dust erosion on the surface to its possible internal composition, as well as the more speculative ideas of cometary migration concern not just 67P but the broader class of short-period comets, many of which visit the Sun at least once every 200 years. Astronomers think their long journeys makes them well-suited to be messengers carrying non-native molecules to worlds that might not have otherwise acquired them – such as those necessary for life on Earth.
In January 1947, the American War Assets Administration dumped drums of sodium left over after the end of World War II into Lake Lenore in eastern Washington state. A video of the event – it really was an event – is available from the Internet Archive.
Sodium’s reaction with water – or most other substances in general – is so violent because of the number of electrons in its atoms. Specifically, each sodium atom has one electron more than the atom needs to be in a highly stable state. That one electron keeps the atom highly unstable, and is given away at the first available chemical opportunity. So, when sodium (Na) meets water (HO–H), it rapidly forms sodium hydroxide (Na–OH) and releases hydrogen (H). Simultaneously, the sodium atoms release their extra electrons to form the molecules, and from go being highly unstable to highly stable. As a result, they produce such heat that the hydrogen is ignited, which burns with a bright flame, even as some of the water boils off as steam.
Even if all of this makes sense – and is true – could there be more to this reaction than meets the eye?
That’s the question a bunch of chemists, from the Academy of Sciences of the Czech Republic and the Technical University of Braunschweig, Germany, chose to ask. They figured the explosive nature of the reaction wasn’t solely due to sodium’s eagerness to react with water but also had to do with how its surface changed shape when in contact with water. Using high-speed cameras, they studied how drops of an alloy of sodium and potassium, another explosively reactive metal, responded when they were dropped into water. Watch this closely.
Credit: Mason et al.
Toward the end of the video (as Thunderf00t explains in the 17th minute), you can see how almost as soon as it is dropped, the alloy rapidly develops spike-like protrusions on its surface, on the underside. These spikes form within a few thousandths of a second, and increase the surface area of the metal that is available to react with water. The scientists calculated based on their video footage that the spikes start and finish extending out of the surface at an acceleration of 10,000 ms-2. That’s almost the same acceleration at which you could be shot out of a space gun.
When they performed the same experiment with a drop of liquid aluminium, they couldn’t see any spikes forming on the metal droplet. Apparently, it happened only with the sodium-potassium alloy. Was it because of the explosion that happens? Nope, because sodium-potassium reacts non-explosively with ammonia, but the spikes formed there again. So it definitely happens only with sodium-potassium.
So, to get their answer, the scientists used a computer simulation, which revealed an all too familiar devil in the details.
As soon as the sodium-potassium drop meets with the surface of water, its outermost layer of atoms loses electrons rapidly to the water – so fast that the transfer happens in a few trillionths of a second. The water molecules accept the electrons and subsequently break down into hydroxyl (HO) and hydrogen (H) ions. As a result, at the interface of the drop and the water, there are now four layers: the remaining drop of sodium-potassium atoms, next a layer of sodium-potassium ions (positively charged because they’ve lost electrons), then a layer of hydrogen and hydroxyl ions (positively and negatively charged, respectively), and finally the rest of the water.
As you can see, there is a layer of positively charged sodium and potassium ions, and like charges repel each other. Because the sodium-potassium alloy is in liquid form, the repulsion manifests as highly distended droplets, or spikes. In technical parlance, this phenomenon is called coulomb fission. The resultant increase in surface area prevents the reaction from stalling, which might have happened if the first layer of sodium hydroxide to form was let to act like a blanket protecting the rest of the alloy.
The English physicist John William Strutt (better known as Lord Rayleigh) first predicted this for liquids in 1882. He reasoned that an electrically charged drop could only contain so much charge before its surface tension gave way and let the drop break up into droplets by ejecting jets – called Rayleigh jets – out of their sides. The Czech and German scientists used high-school math to figure that this breakdown happens as soon as the distance between the sodium-potassium ions and the electrons and hydroxyl ions becomes more than 5 angstrom (one angstrom is a ten-billionth of a meter).
So, that’s one high-school chemistry lesson fully unraveled. How about going after the vinegar volcano next?
The scientists’ paper was published in Nature Chemistry on January 26 .
When writing one of my first pieces for The Hindu, I remember being called out for using a lot of jargon. While the accusation itself may have been justified, the word my supervisor chose as an example of the problem was surprising: “refraction”. He wanted me to spell it out in 10 words or so (because we were already running out of print-space). When I couldn’t, he launched into a long tirade.
It’s easy to spell out the what of refraction in 10 words – just refer to a prism. But if you’ve to understand the why, you’ll end up somewhere in the vicinity of quantum mechanics. At the same time, there are some everyday concepts in our lives that are easier understood the way they appear to be than in terms of what they actually are. This is where I’d draw the line of jargon. While everything can be technically simplified to the predictions of a complicated theory like quantum mechanics, jargon is that which isn’t at its simplest in the most pragmatic sense.
Clearly, this line lies in different places for different people because it can be moved by specialized knowledge. Writing in Nature or Science, I can take for granted that my audience will understand concepts like resonance or Feynman diagrams. Writing in The Hindu, on the other hand, all I can take for granted is reflection and, hopefully, refraction. Then again, these are publications who (ought to) know what their target audience is like. So I ask: If you were writing for a billion people, where would you assume the line is?
What irks me is that – in India at least – the statistical mode for different topics lies at incomparably different places. For example, I would be able to get away with ‘repo rate’ and ‘tortfeasor’ but not ‘morbidity’. My first impression was to somehow peg the difference to the well-established lack of scientific temper. But then I realized what the bigger problem was: news publications in the country are in a state of denial about lacking the scientific temper themselves, and consistently refuse to subject financial and legal news to the same scrutiny and the same wariness with which science news is treated.
If editors really wanted to take responsibility for their content, they wouldn’t let repo rate go through the press, or tortfeasor, or short fine leg, or Brent crude, or fiscal deficit*, or the history of the BJP**. However, they have let these bits of information go through without any apprehensions that they might be misunderstood or not understood at all. And by doing so, they have engendered an invisible reading culture that enforces the notion that these words don’t require further explanation, that these words shouldn’t be jargon – rather, wouldn’t be jargon if not for the reader’s ignorance.
In this culture, business and politics news (henceforth: fin-pol) can be for the least common denominators among all readers while science news… well, science news isn’t for everyone, is it? While the editors have misguidedly but efficiently dejargonized fin-pol news, with the effect that while fin-pol content is considered conventional, science news is still asked to be delivered sandwiched between layers of didactic material.
Another problem – this one more subtle and less prevalent – is that fin-pol reporters can often bank on historical knowledge while science reporters, word for word, remain constrained by the need to break down jargon. In other words, the fin-pol writer can assume the reader knows what he/she is talking about but ‘Feynman diagrams’ have to be repeatedly laid out unless the article is explicitly specified as being one in a series.
*If I can’t use ‘refraction’, you can’t use ‘fiscal deficit’.
**If you refuse to learn from sources other than the media as to who MSR Dev is, I refuse to let myself be persecuted for not learning from sources other than the media as to who SP Mukherjee was.
Astronomers using the HESS telescopes have discovered a new source of high-energy gamma rays. Dubbed a superbubble, it appears to be a massive shell of gas and dust 270 light-years in diameter being blown outward by the radiation from multiple stars and supernovas. HESS also discovered two other gamma-ray sources, each a giant of its kind. One is a powerful supernova remnant and the other a pulsar wind nebula. All three objects are located in the Large Magellanic Cloud, a small satellite galaxy orbiting the Milky Way at a distance of 170,000 ly. As a result, these objects are not only the most luminous gamma-ray sources discovered to date but also the first sources discovered outside the Milky Way.
Gamma-rays are emitted when very energetic charged particles collide with other particles, such as in a cloud of gas. Therefore, gamma radiation in the sky is often used as a proxy for high-energy phenomena. And astronomers have for long known that the Large Magellanic Cloud houses many such clusters of frenzied activity: weight for weight of their stars, the Cloud’s supernova rate is five times that of the Milky Way. It also hosts the Tarantula Nebula, which is the most active star-forming region in the Local Group of galaxies (which includes the Milky Way, Andromeda, the Cloud and more than 50 others).
It is in this environment that the superbubble – designated 30 Dor C – thrives. According to the HESS team’s notice, it “appears to have been created by several supernovae and strong stellar winds”. In the data, it is visible as a strong source of gamma-rays because it is filled by highly energetic particles. The notice adds that this freak of nature
“represents a new class of sources in the very high-energy regime.”
The other two super-luminous sources are familiar to astronomers. Pulsars, especially, are the extremely dense remnants of stars that have run out of hydrogen to fuse and imploded, resulting in a rapidly spinning core composed of neutrons and wound by fierce magnetic fields. They emit a jet of energetic particles from polar points on their surface that form nebulaic clouds. One such cloud is N 157B, emitted by PSR J0537 – 6910. According to the HESS team, N 157B outshines the Crab Nebula in gamma-rays. The Crab Nebula is Milky Way’s most famous and most powerful source of gamma-rays.
The third is a supernova remnant: the rapidly expanding shell of gas that a once-heavy dying star blows away as its core collapses. The shell can be expelled at more than thousand times the speed of sound, resulting in a shockwave that can accelerate nearby particles and heat up upstream gas clouds to millions of kelvin. The resulting glow can last for thousands of years – but the one HESS has seen in the Cloud seems to going strong for 2,500-6,000 years, much longer than astronomers thought possible. It’s called N132D.
“Obviously, the high star formation rate of the LMC causes it to breed very extreme objects,” said Chia Chun Lu, a student at the Max Planck Institute for Astronomy in Heidelberg who analyzed the data for her thesis.
Imaging Cherenkov radiation
Detecting gamma-rays is no easy task because it requires the imaging of Cherenkov radiation. Just as when a jet flies through air at faster than the speed of sound and results in a sonic boom, a charged particle traveling at faster than the speed of light in that medium results in a shockwave of energy called Cherenkov radiation. This typically lasts a few billionths of a second and requires extremely sensitive cameras to capture.
When high-energy particles collide with the upper strata of Earth’s atmosphere, they percolate through while triggering the release of Cherenkov radiation. The five ground-based HESS telescopes – whose name stands for High Energy Stereoscopic System – quickly capture their bluish flashes before they disappear, and reconstruct their sources’ energy based on theirs. So, while gamma-rays can be a proxy for high-energy phenomena in the distant reaches of the cosmos, Cherenkov radiation in the upper atmosphere is a proxy for the gamma radiation itself.
Very-high-energy gamma-rays, of the order emitted by the Crab pulsar at the center of its nebula, are often the result of events that have made astronomers redefine what they consider anomalous. A good example is of GRB 080916C, a gamma-ray burst spotted in 2009 at about 12 billion ly from Earth. It was the result of a star collapsing into a black hole, with consequent ‘burp’ of energy lasting for a whopping 23 minutes. Valerie Connaughton, of the University of Alabama, Huntsville, and one of the members of the team studying the burst, said of its energy: “… it would be equivalent to 4.9 times the mass of the sun being converted to gamma rays in a matter of minutes”.
Natural particle accelerators
Such profuse emissions can behave like natural particle accelerators, often reaching energies the Large Hadron Collider can only dream of. They give scientists the opportunity to study particles as well as the vacuum of space in conditions closer to that prevalent at the time of the Big Bang, in effect rendering the telescopes that study them as probes of fundamental physics. In the case of GRB 080916C, for example, low-energy gamma-rays dominated the first five seconds of emissions, following by the high-energy gamma-rays for the next twenty minutes. As astronomy-blogger Paul Gilster interpreted this,
They might also give us a read on theories of quantum gravity that suggest empty space is actually a froth of quantum foam, one that would allow lighter, lower-energy gamma rays to move more quickly than their higher-energy cousins. Future observations to study unusual time lags like these should help us pin down a plausible explanation.
The Fermi orbiting telescope that spotted the burst is also used to look for dark matter. When certain hypothetical particles of dark matter annihilate or decay, they yield high-energy antielectrons that could then annihilate upon colliding with electrons and yield gamma-rays. These are measured by Fermi. Then, astronomers use preexisting data as a filter to extrude anomalous observations and use it inform their theories of dark matter.
In this sense, the HESS telescopes are important observers of the universe. They comprise five telescopes, of which four, each 12 meters in diameter, are situated on the corners of a square of side 120 m. At the center is the fifth telescope of diameter 28 m. The array, fixed up with computers to work as one big telescope, is located in Namibia, and is capable of observing gamma-ray fluxes in the range 30 GeV to 100 TeV. In 2015, in fact, construction for the more-impressive $268-million Cherenkov Telescope Array will start. Upon completion, it will be able to study gamma-ray fluxes of 100 TeV but with a wider angle of observation and much larger collecting area.
Whether or not the CTA can pinpoint the existence of dark matter, it will likely allow astronomers to discover more superbubbles, pulsar wind nebulae, supernova remnants and gamma-ray bursts, each more revealing than the last about the universe’s deepest secrets.
Once I finished Steven Weinberg’s book Dreams of a Final Theory, I figured I’d write a long-winding review about what I think the book is really about, and its merits and demerits. But there is a sentence in the seventh chapter – titled ‘Against Philosophy’ – which I think sums up all that the book essentially attempts to explain.
Nothing in the history of science is ever simple.
And Dreams of a Final Theory wants to make you understand why that is so. To Weinberg’s credit, he has done a good job – not a great one – with complexity as his subject. I say ‘not a great one’ because it has none of the elegance that Brian Greene’s The Elegant Universe did, and it laid out string theory from beginning to end. At the same time, it is still Weinberg, one of the towering figures of particle physics, at work, and he means to say, first, that there is no place for simplicity in his line of work and, second, even in all the terrible complexity, there is beauty.
The book, first published in 1992, is a discourse on the path to a ‘final theory’ – one theory to rule them all, so to speak – and the various theoretical, experimental, mathematical and philosophical challenges it presents. Weinberg is an erudite scientist and you can trust him to lay out almost all facets of all problems that he chooses to introduce in the book – and there are many of them. Also, I wouldn’t call the book technical, but at the same time it demands its fair share of intellectual engagement because the language tends to get (necessarily) intricate. And if you’re wondering: There are no equations.
In fact, I would be able to describe the experience of reading Dreams of a Final Theory using a paragraph from the book, and such internal symmetry is unmistakable throughout the book:
But why should the final theory describe anything like our world? The explanation might be found in what [Robert] Nozick has called the principle of fecundity. It states that the different logically acceptable universes all in some sense exist, each wit its own set of fundamental laws. The principle of fecundity is not itself explained by anything, but at least it has a certain pleasing self-consistency; as Nozick says, the principle of fecundity states ‘that all possibilities are realized, while it itself is one of those possibilities’.
“Sikkim’s own energy needs of 409 megawatts (MW) were met by 2012, and Chamling already sells 175 MW of extra power to India’s power-starved northern grid. If all 26 hydel projects come on stream, Sikkim should generate 4,190 MW of electricity. But there are a few problems.” (7 min read, indiaspend.com)
“India’s airline industry is a mess. Taxes are sky-high, infrastructure is poor and profit margins are razor thin. A string of carriers have gone out of business, and many others are struggling to stay afloat. Yet the big winners might be price-conscious consumers — and any carrier strong enough to survive the price wars that have made India the cheapest place to fly on Earth.” (3 min read, cnn.com)
“I persuaded Professor Nurul Hasan, then Education Minister, to have the following clause included in Article 51A in the 42nd Amendment of the Constitution in 1976: “It shall be the duty of every citizen of Indian “to develop the scientific temper, humanism and the spirit of enquiry and reform.” But India has not produced any Nobel Prize winner in science in the last 85 years – largely because of the lack of a scientific environment in the country, of which scientific temper would be an important component.” (5 min read, thehindu.com)
+ The author, Puspha Bhargava, is the founder-director of the Centre for Cellular and Molecular Biology at Hyderabad, and chairman of the Southern Regional Centre of Council for Social Development.
“The reason India’s healthcare indicators remain abysmal is not just a question of money (after all, ours is one of the fastest growing economies). The problem is a persistent rash of doublespeak that denies the people a coherent healthcare system. While successive governments have committed to various goals, no government programme has yet focused on the three most important problems facing India’s health at once: a mismanaged regulatory climate, corruption, and the caste system.” (5 min read, scroll.in)
“At the World Parks Congress in Sydney in October, the International Union for Conservation of Nature said their information on the biodiversity that the Western Ghats contained was “deficient” and cautioned that the region was under tremendous pressure from population within and without, from untrammelled resource extraction, residential and recreational development and large-scale hydroelectric projects. “We must know all that exists there before it goes extinct,” says Vasudevan. “Not that we’re not we’re doing much to prevent that.”” (4 min read, qz.com)
Chart of the week
“The 2014 general elections were estimated to be India’s most expensive—and the Narendra Modi-led Bharatiya Janata Party (BJP) broke the bank on the way to its biggest ever election victory. In all, the BJP spent Rs 714.28 crore ($115 million) on the 2014 general election campaign. But its worth remembering that this is only what the parties declare before the Election Commission—and that India’s election campaigns are awash with black money, booze and other persuasive items.” More on Quartz.
In his book Dreams of a Final Theory, Nobel-Prize-winning physicist Steven Weinberg discusses the various aspects of the journey toward a unifying theory in fundamental physics. One crucial aspect is the aesthetic of such a theory, and Weinberg’s principal contention is that a unifying theory must be beautiful because if it weren’t beautiful, it wouldn’t be final in every sense. However, thinking so presupposes all scientific pursuits are motivated by a quest for beauty – this may not be the case. More importantly, beauty in being a human construction can be fickle and arbitrary, and interfere with the pursuit of science.
We are trained to expect nature to be a certain way and we call that beauty. As a result, we strive for solutions that are beautiful, i.e. commensurate with the way we see nature to be. But if the physicist confesses to you that the problems he chooses to solve are so beautiful, then that implies he thinks the problem is beautiful in its own right and independently of its solution’s beauty. Does this mean problem-solving in fundamental physics is dominated by a selection bias: whereby scientists choose to solve some problems over others because of the way they appeal to their aesthetic sense? Weinberg thinks so, and presents an example of scientists going after an ‘ugly’ problem – the thermal demagnetization of iron and critical exponent associated with it (0.37) – in the hope that it will have a beautiful solution. He writes,
Why should leaders of condensed matter theory give the problem of the critical exponents so much greater priority? I think the problem of critical exponents attracted so much attention because physicists judged that it would be likely to have a beautiful solution.
The result of their selection bias is the emergence of a dividing line between what needs to be studied and what doesn’t, between what knowledge is codified in the form of principles and what knowledge remains as individual facts. There is an obvious conflict with objective rationality here, which guides the fundamental investigations of nature and excludes unreasonable judgments like those backed by one’s sense of beauty. It seems, according to Weinberg, we are all motivated only to discover a beautiful universe – one that appeals to our preexisting convictions of what the universe ought to be – as if we are defining the beauty we feel we are bound to abide by. What else are we doing when we reject ‘ugly’ solutions but rejecting a form of the truth that doesn’t appeal to our sense of beauty2? By Weinberg’s own admission, what constitutes beauty1 has been changing with the discovery of more truths: just as beauty was a universality among the dynamics of forces in the early 20th century, beauty in the 21st century seems to be the presence of symmetry principles.
Therefore, by making such decisions, we are actively precluding the ‘existence’ of certain kinds of beauty because we are also forestalling the discovery of certain truths. Weinberg defends this by saying that if aesthetic judgments are working increasingly well, it could be because they are applicable – but the contention he does not address at all is that it is an arbitrary mechanism with which to arrive at the truth. We are simply consigning ourselves to understand beauty in different eras as new deviations from previous definitions of beauty, and removing opportunities to understand other3 (i.e. seemingly unrelated) kinds altogether. For example, the physicist who decides that the ‘ugly’ critical exponent of 0.37 must belong to a more beautiful, overarching theory is immediately pigeonholing other seemingly random exponents to the same fate. What if such exponents are indeed ones of a kind – perhaps even part of a much larger renormalization framework that researchers are desperately seeking to make sense of the many ‘fine-tuned’ constants in high-energy physics, rather than buoys of apparently hidden symmetries themselves that lead nowhere?
There are three additions to this discussion (referenced in the paragraph above):
1. Has beauty always been the pursuit of science? Elegance is definitely a part of the pursuit – if not more – because the elegance of natural phenomena is sure to reflect in the natural sciences, to paraphrase Werner Heisenberg. At the same time, Weinberg goes to some length to mark a distinction between beauty and elegance: “An elegant proof or calculation is one that achieves a powerful result with a minimum of irrelevant complication. It is not important for the beauty of a theory that its equations should have elegant solutions.” That said, the answer to this question is unlikely to be short or general for it questions the motivations of scientists over many centuries. At the same time, some of the greatest scientists – typically Nobel Prize winners – have said the quest for beauty has constituted a significant part of their work simply as an abrogation of randomness. Here is Subrahmanyan Chandrasekhar writing about the work of Lord Rayleigh in his book, Truth and Beauty: Aesthetics and Motivations in Science:
… after a scientist has reached maturity, what are the reasons for his continued pursuit of science? To what extent are they personal? To what extent are aesthetic criteria, like the perception of order and pattern, form and substance, relevant? Are such aesthetic and personal criteria exclusive? Has a sense of obligation a role? I do not mean obligation with the common meaning of obligation to one’s students, one’s colleagues, and one’s community. I mean, rather, obligation to science itself. And what, indeed, is the content of obligation in the pursuit of science for science?
2. We started with the assumption that beauty is what we have learnt nature to be. Therefore, by saying a problem or a solution doesn’t appeal to our sense of beauty, it only means it doesn’t appeal to what we already know. This attitude is best characterized by the tendency of well-entrenched paradigms to not give way to new ones, to not surrender in the face of new knowledge that they can’t account for. An example I am particularly fond of in this regard is the story of Dan Shechtman‘s discovery of quasicrystals, which went against the grain of Linus Pauling’s theory of crystals at the time.
Before introducing the third point (which is optional): While it is clear that Weinberg is enamored by the prospect of beauty legitimizing the study of fundamental physics, all of science cannot afford to be guided by as fickle a metric because beauty is what we expect nature to be – according to him – and that signifies a persistence with ‘old knowledge’ while discovering ‘new knowledge’. That deprives the scientific method of its objectivity. Also, the classification of knowledge impedes what scientists choose to study and how they choose to study it as well, and judging the legitimacy of knowledge based on its beauty lends itself to a mode of classification that is not entirely rational. Finally, that scientists also wouldn’t reject new knowledge if it was ugly but that beautiful knowledge would find acceptance faster and scrutiny slower is not… proper.
3. Orson Scott Card’s Speaker for the Dead provides an interesting way to understand this ‘otherness’. It describes a so-called hierarchy of foreignness to understand how alien a person or object is relative to another, in four stages (quoted from the book): Utlänning, “the stranger that we recognize as being a human of our world, but of another city or country”; framling, “the stranger that we recognize as human, but of another world”; raman, “the stranger that we recognize as human, but of another species”; and varelse, “the true alien … which includes all the animals, for with them no conversation is possible. They live, but we cannot guess what purposes or causes make them act. They might be intelligent, they might be self-aware, but we cannot know it.” Similarly, the ‘other’ kinds of beauty we stand to lose, according to Weinberg, are varelse, while we stick to the more fathomable (utlänning, framling and raman) kinds.
Even after the loss of a critical stabilization system on-board, the NASA Kepler space telescope has made an important discovery. Scientists from the University of California have used the telescope to find a nearby star-system comprising a cool red M-dwarf and three planets slightly larger than Earth orbiting it. The find’s significance stems from various reasons, not the least of which is that this system is only 150 light-years away, close enough for astronomers to make direct observations of the star and the planets’ atmospheres*.
The three planets’ radii are 2.1-, 1.7- and 1.5-times that of Earth. The outermost planet, with the radius 1.5 RE, is in fact on the inner edge of the system’s habitability zone and receives 1.4-times the light that Earth does from our Sun. Moreover, follow-up observations made from the Automated Planet Finder telescope, California, and the Keck Telescope, Hawaii, indicate that the planets’ surfaces are cool and not scorched as exoplanets’ surfaces have often been found to be. The ‘lukewarm’ temperature is a sign that the planets are fully-formed.
For these reasons and others, finding this star-system has been like striking gold for astronomers. Its proximity permits them to closely monitor its evolution than if it had been farther away. The red M-dwarf at its center – designated EPIC 201367065 – is not too bright or its electromagnetic flux would have ‘bleached’ out observations; its moderate emission also means the planets’ surfaces aren’t scorched. The almost Earth-sized planet just about in the habitable zone means they can study if its surface conditions are conducive to life (A recent analysis concluded that one in five Sun-like stars in the Milky Way hosts an Earth-sized planet in the habitable zone, which means there are 40 billion such planets in our galaxy alone). Making matters easier overall is the proximity of the system itself, which also means investigations can be more detailed for the same resources.
One such detail that has not been explored with any great precision among farther exoplanets is composition. With sizes in the 1.5-2.1 RE range, the study’s authors think “they may span the gap between rock-dominated ‘Earths’/’super-Earths’ and low-density ‘sub-Neptunes’ with considerable volatile content”. Compositional analyses are important to understand what kind of planets can form under what conditions and how their orbits could have migrated within the system before attaining equilibrium. Additionally, they could also help astronomers understand why there are no planets heavier than Earth but lighter than Neptune in our Solar System.
Anyway, the next course of action will be to use the Hubble space telescope to compose a spectroscopic map of the outermost planet’s atmosphere. Many exoplanets that possess atmospheres also possess hydrogen-rich atmospheres, with no hints of the oxygen and nitrogen that have been able to support life on Earth. If the outermost planet’s atmosphere is also dominated by hydrogen, then the gas’s presence will show up in Hubble’s measurements. As the study’s lead author Ian Crossfield, from the Lunar & Planetary Laboratory at the University of Arizona, noted, the presence of large quantities of hydrogen doesn’t preclude life but only life as we’ve known it on Earth.
The study’s paper was uploaded to the arXiv pre-print server on January 15 and has been submitted to the Astrophysical Journal.
*Although the ten closest star-systems that have exoplanets are within 20 ly of the Sun.
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