Hiking, Skydiving and Booze: The Future of Exoplanet Tourism

 

Today, NASA released another poster in its wonderful ‘Exoplanet Travel Bureau‘ series. I’ve been a big fan of these prints since their inception; a fun and colorful outreach project that captures the diversity and exotic nature of these newly discovered worlds. However, they could be interpreted as more than just a NASA public relations project. If we consider art as a particular subjective interpretation of reality, subject to the fads, fashions and cultural context of the time, then these posters actually say quite a bit more!

They not only portray our early depictions of these enigmatic worlds, but our interpretations of what these planets may be like also sheds some light on our view of ourselves and the future. All the posters have a clearly evident retro-futuristic theme. A view of the future, but from the past. From the font choices, fashions and colour schemes, these posters are depicting the future of humanity, but through optimistic eyes of 1960s design, when flight and space exploration were developing at extraordinary rates, and holidaying on the Moon or Mars seemed only years away. By drawing on retrofuturism and space-age pop-art consumerism, the artists are trying to capture the anticipation and optimism of mid-20th century space science, and focus that enthusiasm on the hunt for Earth-like worlds, perhaps drawing parallels between the rate of planet discovery and that of aeronautics and space exploration during the 60s.

PSO J318.5-22 – Where the Nightlife Never Ends

The newest poster in the series depicts exoplanet PSO J318.5-22, a ‘rogue’ planet that has been ejected from its star system and is now sailing through interstellar space, but has since been turned into a party location by our intrepid descendants. To be honest, I really like this print. The throw-back to 1960s retro-futurism is undeniable, and this poster oozes cool and class – an elegant couple in minimalist spacesuits step out into the perpetual nightlife of a rogue exoplanet, a world so bizarre and strange that a few years ago the very idea of would have sounded preposterous. But here we are, turning an astronomical absurdity into a planetary-scale nightclub, all the while looking suave and beautiful as only humans can do. The simple duality of colors really capture the cold, cool and classy vibe, using blues, purples and silvery hues that gleam like auras off our descendants’ ‘nightclub-in-space’ regalia. In the background, figures stand suspended what appears to be a walkway along one of the planet’s icy rings, as more spaceships replete with party-goers arrives in sequence.

The three other posters in the series also adhere to a similar visual style. The print for Kepler-186 f depicts a couple exploring the striking red vegetation of this planet, the first Earth-size planet discovered in the potentially ‘habitable zone’ around another star. Its host star, Kepler 186, is a red dwarf, a much smaller star that emits more light in the red and infra-red portion of the electromagnetic spectrum than our Sun, and it is thought that if photosynthetic organisms were to exist on the surface of Kepler 186 f, they would be red in colour to exploit this fact. An interesting aspect of this poster is the white picket fence, a staple of American suburban utopia, that separates the green and red vegetation thereby accentuating the ‘grass is greener’ trope. Here, Earth-bound familiarity is juxtaposed against the alien backdrop of red foliage, and is proof that no matter how weird or exotic these worlds may be, the power of human culture will eventually make even the strangest of environments familiar to us.

When considering the artists’ interpretation of Kepler-16b, it is clear that the binary star system is the draw here. The unusual stellar architecture of this world would indeed make for a stunning double-sunset. Often considered a romantic activity best shared as a couple on Earth, here a single human figure enthralled by the graceful choreography of the binary is accompanied by two shadows instead.  Although likely much too cold for life, Kepler 16b is portrayed in familiar desert tones of ochra and red, perhaps reminiscent of planets in binary systems in popular culture.

Experience the Gravity of a Super Earth

So what if HD 40307 g is eight times as massive as the Earth? We can turn this to our advantage, and thrill-seeking human skydivers are invited to plunge at incredible speeds through its (probably) thick gaseous atmosphere. Why? Because we can. Because we’re humans and evidently the whole galaxy is our playground.

The fact we know relatively little about these planets actually helps in this case, as imagination and artist license can run rampant. Significantly, these prints frame these worlds as utilitarian or ‘useful’, but not in the traditional economic or scientific sense. They’re useful and subservient to a human species so technologically advanced that even our recreation and tourism is now planetary in scale. There’s not much science being depicted, and that’s fine. These are travel posters for the future middle-class, an invitation to come for the exotic sights and stay for the booze, hiking or skydiving. The limited depiction of ‘life’ in these posters is somewhat unimaginative – a few red trees and the tinge of green on a continent, but I think that’s for the best at this stage. Overly stylized images of alien life would detract from the fact that humans are as much the focus in these posters as the alien planets.

The fact that we’re portrayed as out there using entire worlds for our recreation and fun speaks to the optimism of the search for extrasolar planets, and is well mirrored by the retro style employed by the artists. Unfortunately, being able to travel to these worlds is, in reality, completely unfeasible with contemporary technology, which makes the promises of lavish parties in deep space somewhat bittersweet. Nevertheless, I hope that NASA continues to publish posters in this series, and I look forward to seeing their next effort!

 

 

 

Planets of Purpose: Desolation and Meaning in an Empty Universe.


There were two kinds of landscape characteristic of the inner planets of the Sun: the purposeful and the desolate.

Stanislaw Lem – Fiasco (1986) [Ch.1, tr. Michael Kandel]


A loose rock tumbles slowly down a slope in a lonely valley on Mars. The hill of its origin seems unfamiliar and alien – it is more crimson and notably steeper than any rise on Earth due to Mars’ oxidizing environment and lower gravity. A loose conglomerate of ruddy scree, it seems completely devoid of life. The rock, idle in its elevated resting place for perhaps eons, now dislodged by a chance landslide caused by a violent Martian windstorm, rolls to a stop in a new location in the dry valley below. No human eyes have ever seen this boulder, no one has sat atop it to survey the panorama of the valley where it sat, or pounded it with a rock hammer to determine its composition, or crudely scrawled their initials into its surface in an attempt to immortalize a teenage love affair. What purpose, if any, does this boulder serve? Life cannot shelter beneath it or break it down for nutrients because no life exists on this frigid, desiccated planet. It inhabits an exclusively abiotic world, and whilst it will be shaped by powerful winds into exotic and unfamiliar forms, it will eventually be blown to dust by the continual onslaught of sandstorms, dissipating gradually, grain by grain, into the chaotic atmosphere. The universe seems no richer for its passing.

http://io9.com/uncanny-places-on-earth-that-look-like-alien-planets-1444739857

An alien world? Actually, this is the Atacama Desert in Chile, possibly the world’s oldest desert and one of the driest places on the planet. (via i09.com/Benjamin Dumas)

Desolation is a ubiquitous feature of the solar system. From the barren, scorched and pockmarked surface of Mercury, to the icy solitude of the gas giants, and out to the lonely minor planet Pluto in its long, dark trundle around the Sun, these are entire worlds devoid of life and the patient sculpting of natural process we are so familiar with on Earth. Their terrain is of great interest scientifically, but it is obvious that these are worlds very different to our own. They lack a certain something, an inherent dynamism that it seems only biology can imbue. They seem alien, and they are in some sense, but this feeling of other-worldliness issues forth from the unfamiliar landforms and empty horizons, broken here and there by topographies of pure abiological physicality. Nothing about these geographies serves a ‘purpose’. The craters of Mercury, or Mars, or any of the moons of Jupiter or Saturn, stand magnificent in their grandeur, but alone in the emptiness of space: many will never be explored, never investigated, chaotic in their form and distribution, but ultimately meaningless in their existence.  It is my expectation that if we were to find another planet on which life had a foothold, that world would seem somehow more familiar to us, if undoubtedly exotic and bizarre, than a planet entirely devoid of biology.

This lack of purpose, of meaning, is obviously an inherently human concept, and whilst it results in an obvious planetary dichotomy (as illustrated by the quote above), it is this contrast that should provide us with perspective on our own planet and a greater appreciation for even the smallest action borne from the ancient, intimate dance between life and our world, choreographed by natural selection and honed by a run lasting billions of years. For if we consider these alien features to be meaningless and purposeless, it follows that the only ‘purpose’ that exists is that which began on Earth, and which emanates now ever outwards, shaping, and in some cases, biasing, our view of these barren worlds. Meaning is a concept that we as humans can and do impose upon desolate landscapes. We name features on distant planets, we photograph their lonely surfaces and seek explanations for their existence, but only as an aside in our quest for a greater understanding of our place and purpose. Even here on Earth we occupy the least biologically productive environments, sometimes for science, or for economic gain, or just for the challenge, but by our very presence in these once vacant landscapes, we provide a center of purpose. The once empty environment now provides a backdrop to the human drama, an extension of the boundless stage on which we carry out the acts of our lives; a silent witness to hours, days or years of collective human strife and trivialities. But is this really all meaning is? An inherently dichotomous characteristic of place that only exists relative to biology’s insight or attention?

In searching for a word to convey this sense of emptiness, of this abiotic ‘nothingness’, the limitations of terrestrial linguistics shaped by our Earth-bound experiences and history are revealed, and the true magnitude of the desolation – often global, near complete – remains difficult to comprehend and to express cogently. A world without any ‘meaning’, any direction, any sense of teleological drive. An environment surrendered to entropy and shaped by chaos and the haphazard actions of an abiotic ‘nature’. This is a nature unbounded by the necessities of life, in which soils and rocks remain untouched by biology but are instead molded, as clay in the hands of an inanimate potter, by purely physical processes: wind, fluids, irradiation and planetary tectonism. It seems that these are the environments most favored by the universe as they litter our solar system, and almost certainly exist around billions of other stars in our galaxy and beyond. Can it really be that an entire galaxy could exist in this state of meaningless stasis? Barren, empty reaches awaiting the arrival of life to imbue meaning upon the void?

It is possible that humans are the only intelligent observer species ever to have arisen in this galaxy. If that is the case, we have a great responsibility, not only to preserve our planetary sanctum for future generations and to continue to unravel the esotericisms of the universe, but to further safeguard our existence as the fount, the point source, of absolute meaning. The universe, it seems, is indifferent to our struggles, but we can elevate ourselves above the insignificant by our individual introspection and collective scientific extrospection.

We are the Gods of Purpose, and all the universe is our Eden.

Exoplanet Astrology: Your Guide to the New Planets

Everyone trusts those great sages of our times, those for whom the intricate secrets of the universe are revealed by the night sky. As wise celestial engineers, the mechanics of the cosmos are obvious to them, the connections between the astronomical and the interpersonal are one and the same. These are people fluent in the language of the stars and skilled at interpreting their enigmatic relationship with humanity, akin to the unfurling of a stellar map of our collective psyche. Scholars all, who undertake years of dedicated study of ancient tomes going back hundreds of years, they have peered into the windows of our souls and seen the nuclear furnaces of the stars themselves.

I’m talking, of course, about astrologers. These wise, charitable, true scientists of our age, who dispense this precious knowledge for only the price of a premium-rate phone call or a column in a lifestyle magazine, to any and all comers. Can you think of a more noble profession?

It pains me however, as a relative newcomer to the field, to note that our astrological maps may be somewhat incomplete! Whilst the stars and constellations – whose graceful dance through our personal lives can be traced with ease by gifted astrologers – are relatively fixed in their positions (on human timescales), those charlatan astronomers have since discovered many, many more planets than the astrological academy may be aware.

Of course, let us not forget the effect of angry Mars on your unwavering passion to join the military, or that of powerful Pluto on your impending rebirth, kidnapping, or initiation into an underground crime syndicate 1. But what of the 1800 exoplanets discovered in the past decade or so? What of their effects on the minutia of your slow, inconsequential trudge to the grave? Well, thankfully, I’ve spent literal minutes conducting my own research on the astrological importance of some of these bodies, and now feel as qualified as any astrologer out there to suggest that you make important and possibly life-changing decisions based on the information I am about to provide to you 2.

The number of exoplanets in each sign of the zodiac, courtesy of the the Planetary Habitability Laboratory.

Here are my predictions for the first four signs! More will follow soon of course.

(Or, alternatively, you could send a text message which will be charged at standard rates, plus £3.50, or visit my pop-up and clickbait-infested website below.)

Sagittarius

The constellation Sagittarius is positively awash with exoplanet-hosting stars, so hold on to your tarot cards because the astrological energy emanating from this sign may well disrupt your centre of balance if this month. HD 179949 b is a ‘hot-Jupiter’ – a massive planet orbiting very close to its parent star, which moves into the sign this week. Like this tumultuous world, you’re feeling increasingly resistant to spectroscopic analyses of your atmosphere, and are keeping evidence of titanium and vanadium oxides close to your chest, possibly to secure a promotion at work. This might seem to be a good strategy now, but your low bond albedo and furnace-like temperatures may make you hot under the collar – a prime target for infrared studies.

Capricorn

This month you may notice a feeling of cold eccentricity creeping into the trivialities of your everyday life. This is probably because of the effect of HD 204941 b on the goat sign this month – a frigid Neptunian planet with an off-center orbit who seems destined to cause a cold-spell in your love life. Detected by the sensitive HARPS instrument, like this planet you need to warm up to those close to you, especially if they’re astronomically massive spheres of super-heated plasma undergoing nuclear fusion, and accept that your radial velocity is discernible from light years away. You have to learn to embrace it and move on! Try sublimating a relaxing herbal or chi tea into your chaotic atmosphere as you near aphelion to help you unwind.

Aquarius

Good news! You may find yourself appreciating your relationships with your family members this month. The red-dwarf Gliese 876 is ascendant in this sign and like its extended family of four exoplanets, you’ll notice your loved-ones adopting a stable, coplanar Laplace resonance of 1:2:4, which will bring you neither further away nor any closer together, for the next 4 billion years at least. Be aware of co-workers and friends however, who like Gliese 876 itself will react in a highly unpredictable ways to your new-found stability, and will be prone to X-ray emissions. Steer clear girlfriend!

Pisces

Pisces is inundated with exoplanets, all of whom are jostling and vying for an chance to directly affect the fleeting existence of a billion apes on a tiny planet several light years distant. Can you not feel them? This month, like the gravitational interaction between Saturn-sized exoplanet HD 3651 b and its distant brown dwarf companion, you’ll feel like people on your extremely distant peripheries are disrupting your already highly eccentric orbit as a Pisces over the coming weeks. Just as NASA’s Spitzer Space Telescope directly imaged this system in 2006, so you’ll have the opportunity to compare existing theoretical evolutionary models to these substellar naysayers as we near Christmas. Just ensure you take some time out of your 62 day year for yourself!

Well, that’s all for now exoplanet astrology fans, but not to worry, I’ll be back with my readings of the remaining signs once I’ve had a chance to adjust my flux capacitor and have rechecked my calculations. Until then, remember: the whole universe is watching you. All the time. Wherever you are, and what ever you’re doing.

This was a guest post by the worlds foremost exoplanet astrologer, Dr Jawbone Hyurns. Follow him on Twitter for regular astrological and exoplanetary updates!

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1 In case it wasn’t obvious by now, this post is satire. However, these particular statements are actually based on stuff found online, where it was claimed Pluto is the planet of terrorism, death, obsession and kidnapping. Pluto’s taking its demotion to minor planet pretty hard it seems, and the astrologers still haven’t caught up on its new classification. I did consider including references, but felt an ethical obligation not to provide traffic to these sites. I took a virtual bath afterwards.

2 Thanks, as always, to the Planetary Habitability Laboratory for their exoplanet astrology resources!

That Tingling Feeling

 

There is a word in Japanese, Yūgen (幽玄), derived from the study of Japanese aesthetics with no English equivalent, that perhaps comes closest to describing the profound sense of the enormity of the cosmos: to despair and be humbled by the insignificance of the struggle against the indifference of the universe, whilst also appreciating the sad beauty of human suffering. I often find myself grasping for a word to describe this reaction when discussing astrobiology with people, other scientists or members of the public, who find the entire field incredibly depressing; who, at some level, acknowledge the futility of our search for meaning in the distant reaches of space. Some find the emotional burden too great to bear, triggering a minor existential crisis. “It’s better not to know”, they say, “Not to think about it. Besides, [insert reality TV show name here] is on!”

On one hand, who can blame them? It’s not like we’re expecting answers to many of The Questions that astrobiology and astronomy are trying to solve in our lifetimes. Science is a gradual process after all, and one that will last as long as there are still questions to be answered. The relative insignificance of our personal lives, our careers and relationships, cast against the enormity of the cosmos and separated by orders of magnitudes of space and time, so clearly presented, can prove a bit too much. The Astronomical Perspective can be overwhelming, and astronomy, as Carl put it, is a humbling experience. I’d like to adopt yūgen as a general descriptor of these feelings.1

Yūgen-inducing perspective: Over the Top. Credit: Luc Perrot

Astrobiology is a scientific discipline practised from deep within in the realms of bounded rationality. These bounds stem from a definite, fundamental and detrimental lack of information about the system, as well as a possible cognitive and technological limitation in processing of the limited information available to us. We definitively lack the resources to arrive at an optimally rational conclusion regarding our place in the universe, the existence of suitably habitable environments elsewhere, and the possibility of life on other planets.  And yet, we know we’re close. We suffer a kind of collective Dunning-Kruger effect regarding how little we know, and how little we know about how little we know. We’re approaching that greatest of unknowns, cobbling together a piecemeal scientific narrative as we go, but missing so many parts of the puzzle that it’s not even clear what it is we’re building. Yet, something innate drives us onwards. Some part of us that has always been, as if a distant memory or half-remembered dream, within our genetic luggage and passed on to us from pre-human ancestors.

The size of our brains relative to our body size (also known as the encephalization quotient (EQ)) has, in fact, gotten smaller in recent times, peaking ~30,000 years ago after 2 million years of expansive growth. I’ll leave the anthropologists to argue over why and what this means, but making some crude assumptions about intelligence and EQ we can assume, therefore, that our extremely distant ancestors may have gazed up at the canopy of the night sky and felt that same intangible yearning as we do. At least, there seems to be no cognitive reasons that they couldn’t have done so. Maybe it was even more pronounced by the gulf of knowledge that separates their knowledge of the cosmos from our own? The bright band of the Milky Way stretched out overhead, unobscured by pollution, but hidden by ignorance; an unknowable story waiting for a narrator, one that would not arrive in earnest for thousands of years. In the meantime, complex and anthropomorphic mythologies were borne and woven by the tapestry of human imagination and fuelled by our penchant for storytelling.

Perhaps, that sense of insignificance, that yūgen, was even more heart-wrenching in the very distant past when we were young, when our contemporary achievements in understanding of our place in the greater Story would seem unfathomable, akin to magic. Perhaps, yūgen has been a driving force in our history as long as we have existed? I’m not suggesting an evolutionary driver akin to bipedalism, but perhaps a minor constituent of the human story that contributed an unquantifiable edge to our tale. An ember burning near the edge of the campfire of humanity’s intellectual awakening, smouldering away throughout the ages whilst we built our temples and cities, waged our wars and battles, waiting for the spark of enlightenment to burst into an inferno of curiosity and discovery.

That’s why I’m optimistic about our search. Sure, we may not find any concise answers to the ‘big’ questions in our lifetimes, and we’ll probably always have that sense of yūgen when faced with incomprehensible enormity on galactic and light year-scales, but rather than hiding in the dark, we should embrace the feeling of astronomical despair and turn it into a creative force for discovery! If you don’t like being insignificant, find something that makes you significant. Yūgen will be passed on to the next generation of curious scientists and philosophers, and as it has done in the past, it will drive us on to more profound questions and more mysterious unknowns.

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1 If any Japanese speakers are reading this, please let me know if I’m using this word incorrectly – my understanding is that the context is important.

Throwing Paradigms to the Wind of Climate Change

       

This is a guest post by Daniil Bachkirov, a joint master’s student in the School of Environmental Sciences and Philosophy at the University of East Anglia, where he studies at the juncture of the natural sciences and the humanities in order to use interdisciplinary philosophical, historical and political insights to solve the environmental crisis. He can be reached by email, and (from September) can be found at the Brockwood Park School in Hampshire. 

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Calls for a collective behavioural and attitudinal shift with regards to the environmental crisis abound these days, but does the language we use reflect want individuals want? Are there cultural processes at work that we continue to participate in even when we’re basically saying, “We want things to be different?” And can these cultural processes actually undermine our capacity to change our attitudes?

While it may seem piddling to be talking about language when there are real, observable, physical processes and social inequalities at work that threaten life on this planet, I ask, what enables us to come together and act on these issues? Language!

For that reason, I want to inquire into the specific terms we use to call for these “collective behavioural and attitudinal shifts”.

When Thomas Kuhn, philosopher of science, wrote in 1962 about the way in which scientific theories and practice were embedded within structures that validate certain ways of understanding nature whilst discrediting others, and that these were subject to change over time, it is unlikely that he would have anticipated the degree to which the word for these structures; “paradigms”, would find usage beyond its original meaning, as they have today. In particular, the idea of the “paradigm shift”, where a dramatic intellectual rift occurs in the scientific community about the fundamentals of scientific knowledge, after which one idea usually triumphs over another, turned out to be a popular way of referring to other kinds of shifts in ideas. You could say it’s almost a cliché.

I want to question the popularity of the “paradigm shift”. It is problematic on two fronts: Firstly, it seems to be indicative of a kind of ‘problematising’ that implicitly defines the environmental crisis in scientific terms, i.e, it is a crisis that can be reduced to the physically observable and therefore we can only act to prevent crises with sufficient objective certainty. This normalises one discourse at the expense of others. Secondly, it might not be an accurate term to describe how ideas and practices actually shift in societies. Societies after all, are far more complex than the shared scientific understandings that Kuhn called “paradigms”.

Paradigm Rift (Superglitch comics)

So, firstly, what do I mean by discourse? Broadly speaking: a set of practices and beliefs expressed through dialogue in a given culture. It is a central concept in the work of the postmodern French philosopher, Michel Foucault who was interested in examining the conditions necessary for the validation of knowledge about human beings at certain times and places. He developed an “archaeological” method to excavate historical artefacts, i.e. texts, to establish how knowledge becomes an instrument of power.

Central to this process, and the term I want to offer as a non-scientistic, more open-ended conception was the idea of the episteme, or the “epistemological field of power” which creates the necessary conditions for the emergence of knowledge. These epistemes flow into one another with no natural rhythm or progression, but can be metaphorically expressed as changing climate patterns. In this sense, Foucault was not interested in the weather, i.e. isolated ideas and historical figures, but the climate; the complex interrelations that create the weather.

I’m asking the reader to consider the potential social effects of using “paradigm shift” to refer to social and behavioural shifts in our attitude to global climate change. Does this usage not imply that everyone in human societies, like a group of scientists in the 16th century moving from the Ptolemaic to the Copernican model, is at the same level of understanding and appreciation of the problem of global climate change to collectively understand and choose to act upon a shift to a “new paradigm”?

Does it also not imply that global climate change is only a problem for science? And if the dominant ideology in scientism happens to be one of materialism, does using “paradigm shift” not add to a climate of popular understanding that the problems of climate change can be reduced to its materially observable effects?

We need to remember that when we call for a “paradigm shift” in our environmental beliefs and practices, we are employing a metaphor from the world of science. Metaphors work on the principle of shared understanding and reveal value-laden, culturally embedded meaning-making processes. They also work on the principle of “feedback loops”, so that those meanings and values embedded in a metaphor are circulated back into society through their regular use, validating those meanings and values.

Might we consider using a term more focused on the broad analysis of intellectual climates rather than a metaphor from a specific discipline? Or better yet, abandon the call for “paradigm shifts” all together?

Dead Stars Reveal Mysteries of Planet Formation

       

This is a guest post by David Wilson, a PhD student in the Astronomy and Astrophysics group at the University of Warwick, where he studies the remains of planetary systems around white dwarfs (see below!). He can be found on Twitter and blogs about various astronomy topics at Stuff About Space.

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Twenty seven years ago astronomers noticed something strange about the white dwarf star GD29-38.

White dwarfs are dead stars, the burnt out carbon cores of stars like our Sun which have exhausted their hydrogen fuel; incredibly dense, incredibly hot balls of matter roughly the size of the Earth. Because of their high temperature, tens of thousands of degrees, all white dwarfs glow blue.

But the light from GD 29-38 wasn’t just blue. When it was split into a spectrum, separated into a rainbow of separate colours, there seemed to be something else there. Something shining with an infrared light, beyond the range of our eyesight.

Initially the discovers were excited, as the red light could have come from an orbiting brown dwarf, a mysterious object several times bigger than a planet but much smaller than a star. But both the white dwarf and the infrared source were pulsating slightly, periodically getting brighter and dimmer. If the red light was from a separate object, then it shouldn’t have pulsed in time with the white dwarf.

An asteroid plummets to its doom around the white dwarf GD 29-38. Studying the debris left from these asteroids can reveal the chemical composition of exoplanets. Image Credit: NASA

The spectrum also revealed metals in the white dwarf’s atmosphere, heavy elements like calcium, magnesium and iron. These were also out of place, as white dwarfs have such a strong gravity that anything heavier than hydrogen or helium should have sunk down into their cores long ago. The metals must be falling onto the white dwarf from the space around it- but how did they get there?

It took until 2003 for the origin of the mysterious infrared glow to be found, during which time many more white dwarfs with similar red spectra and metal polluted atmospheres were found. The explanation was that the infrared light is coming from a disc of dusty debris surrounding the white dwarf.

This debris was formed from the wreckage of an asteroid, leftover from when GD29-38 was a Sun-like star with its own system of planets. The dust in the disc rains down onto the white dwarf, explaining the metals we see in the atmosphere.

The spectrum of GD 29-38. Along the bottom is its wavelength, or colour, going from blue on the left to invisible infrared on the right. The vertical axis shows how bright the white dwarf is at each wavelength. The difference between the blue white dwarf and red dust cloud can be clearly seen. Image Credit: NASA

The spectrum of GD 29-38. Along the bottom is its wavelength, or colour, going from blue on the left to invisible infrared on the right. The vertical axis shows how bright the white dwarf is at each wavelength. The difference between the blue white dwarf and red dust cloud can be clearly seen. Image Credit: NASA

The story of how the debris disc got there is a result of the turbulent formation of the white dwarf. As it runs out of fuel a star swells up to a huge red giant, then blows away roughly half of its mass in an immense stellar wind, leaving the tiny white dwarf core.

With the gravitational force at its heart cut in two, the system of planets around the dying star is thrown into chaos. Planets begin to migrate outwards, trying to reach orbits twice as far away from the central star as before. As they do this, they risk coming into close contact with each other.

Some of the planets survive these encounters and carry on as they are. Others, especially when a big Jupiter sized planet is involved, are thrown out of the system into the depths of interstellar space. And some are scattered into the centre of the system towards the white dwarf.

These unlucky asteroids and dwarf planets fall in towards the white dwarf until they reach a point known as the tidal disruption radius. There the tidal force, the difference in gravitational pull between the parts of the asteroid nearest the white dwarf and the areas further away, becomes so great that the asteroid is ripped apart, forming the dusty debris disc that we see as an infrared glow.

The discovery of this process lead to an important conclusion. As the dust rains down onto the white dwarf it becomes visible to our telescopes. If we can measure what metals there are, and how much of each there is, then we can reveal the chemical composition of the asteroid or planet that formed the disc. We can ask, and answer, the question: “What are planets made of?”

Two decades ago we only knew about the eight planets in our solar system (Pluto was never a planet, it was just mislabelled). Now we know of over a thousand planets, new worlds orbiting hundreds of stars. Through our telescopes we can measure the size of these planets, what their masses are, and even in some cases get a glimpse into their atmospheres.

But we can’t find out what they’re made of, what the geology of these newly discovered planets is like. This means that we don’t know for sure if the way that the rocky planets are built in our solar system, the particular mix of iron, oxygen, magnesium, silicon and other chemicals that make up the Earth and its neighbours, is the way all planets are built.

The metal polluted white dwarfs form a perfect laboratory, presenting us with rocky objects that have broken apart into their chemical components. By observing as many as we can, we can begin to explore the chemical diversity of planets and planetary systems. We can see if the way our planets are built is the normal way to construct a planet, or whether Earth is even more unique than we thought.

To date we’ve discovered around a dozen white dwarfs with enough chemicals to compare their systems in detail with our own. So far, they look fairly similar to the Earth, a hopeful sign. But we need many more to truly explore this area, and over the next few years myself and others will be scouring the sky, using the Hubble Space Telescope above us and an array of telescopes on the ground. We will find more metal polluted white dwarfs, measure the chemicals of the planetary debris around them, and begin to explore in detail what things you need to build a planet.

The future of life detection on Mars: We come in peace, but carry lasers!

       

This is a guest post by Samantha Rolfe, a PhD student at the The Open University’s Department of Physical Sciences, where she is researching potential biomarkers on Mars using Raman spectroscopy. You can find her on Twitter, or talking science on Radio Verulam

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The robotic exploration of other planets has been happening for many decades now. We have been to almost all the classical planets, with the New Horizons mission presently on its way to the Pluto‑Charon system (Pluto will always be a planet in my heart). Among the earliest fragile feelers of this type were extended in the 1970s in the shape of the Viking missions to Mars. Mars has been the subject of speculation for over a century in the minds of humans when considering whether we are alone in the Universe. For many years, almost right up to the landing of the Viking missions, it was believed that Mars had vegetation on its surface; Italian astronomer Giovanni Schiaparelli thought he had observed a network of linear ‘channels’ on Mars during observations in 1877, which was later mistranslated as ‘canals’ by Percival Lowell, further fuelling the fire that intelligent Martians existed there. However, images from the Mariner program showed the surface to be littered with craters, a surface similar to that of the Moon.

The first ‘clear’ image from the surface of Mars sent back by Viking 1 shortly after landing (NASA/Roel van der Hoorn).

The Viking landers were sent with life detection instrumentation, the results of which proved inconclusive (though recent reanalysis shows they may have detected organic material but it was masked by geochemical processes that were not understood at the time) and this led to pessimism about finding life elsewhere in the Solar System in planetary science departments around the world. Nonetheless, with improving technology and further study of Mars from orbit and the ground has revealed that Mars definitely had areas of standing and running water on its surface for a significant amount of time; long enough to create fluvial fans, sedimentary stacks and rounded pebbles, which are amongst the evidence for liquid water. These discoveries, along with the developing discipline of astrobiology, have forced us to continue looking for the potential of Mars as a habitable planet.

The concept of habitability has been stretched in recent years with the in depth study of extremophiles, often single celled organisms (though they can be found on all three branches of the phylogenetic tree) living in conditions where humans would instantly perish. Examples of terrestrial life living at extremes of temperature, pressure or salinity, for example, makes for an interesting case that Mars may too host life. Liquid water can only exist at the surface of Mars if its freezing point is depressed to extremes, evidence of which has been found in the form of Recurring Slope Lineae – streaks seen to lengthen and retreat with the seasons on crater walls – if there is liquid water at the surface, perhaps there are reservoirs in the subsurface which life could utilise.

Recurring Slope Lineae in Newton Crater on Mars, evidence for liquid water at the surface (NASA/JPL-Caltech/Univ. of Arizona).

Future missions to planetary bodies will be employing new techniques to search for life. Raman spectroscopy is one of these techniques. A non-destructive laser is fired at a sample and some of the reflected photons are engaged in a non-elastic interaction with the sampled molecules, slightly changing the frequency of the returning light. This is displayed as spectroscopic peaks or bands representative of the individual bonds within the molecule. Therefore, each molecule has its own unique Raman spectrum allowing the identification of organic and inorganic molecules even within a mixed matrix of materials, making it a useful tool for life detection.

The present surface conditions of Mars are not forgiving to the survival organic material or, therefore, its detection. The surface is known to be an oxidising environment, leading to the destruction of organic material that may exist at the surface of Mars. The Martian subsurface may be protecting organic molecules waiting to be detected as tantalising evidence for the possible existence of life on the Red Planet. ESA’s ExoMars mission, due to launch in 2018, will be carrying a Raman spectrometer and ideas for future missions to Jupiter’s moon Europa are also considering strapping a Raman spectrometer to them and throwing it into the extreme radiation environment of the Jovian system.

Before we land on these planetary bodies, we can test what we think we are expecting i.e. can organic molecules be detected in simulated Martian environments? Experiments have shown that organic molecules such as amino acids are able to survive Martian surface conditions, for perhaps millions of years (extrapolated) in small quantities (parts per billion). In the harsh light of the Martian day (where the atmosphere does not block the ultraviolet radiation from the Sun as effectively as the Earth’s does), the Raman signatures of amino acids are degraded. Similar results are seen for microbes, such as Deinococcus radiodurans. Their Raman signatures have been analysed and examined after exposure to the ionising radiation environment expected at the surface and near surface of Mars.

If we are to discover organic molecules or even microbial Raman signatures on Mars then it is apparent that we will need to dig or drill down into the subsurface, beyond the depth where destructive ultraviolet and ionising radiation can penetrate. For ultraviolet, mere millimetres of regolith can block harmful rays, but the depth to which ionising radiation is able to penetrate is thought to be at least 2 m below the surface. Luckily, ExoMars will carry a drill with the ability to bore to a depth of 2 m (see what they did there?). Drilling to this depth has never been attempted before and will be a great feat of engineering if achieved. Samples recovered from the subsurface will need to be handled with great care and be removed from direct interaction with the Martian daylight as experiments have shown that Raman signatures of some organic molecules can begin to degrade within seconds, losing vital information about potential life that may exist or have existed in the subsurface.

A typical Raman spectrum of the amino acid Alanine, used in biological processes, most commonly in the building of proteins.

Raman spectroscopy is only some of what we have to look forward to in terms of future martian life detection missions and with all the new information we have been gathering with Curiosity of the Mars Sample Laboratory mission in Gale Crater (rounded pebbles indicating long term presence of liquid water, Mars is not red all over but grey too – a sedimentary rock, ‘John Klein’, was drilled into, a first in Mars exploration, and was found to be grey under the surface with analysis being consistent with clay minerals), we can only imagine what we might find in the future. Especially given that Curiosity’s mission is only to assess the habitability of Mars, not search for life, we have so much to look forward to.

 

Despite the amazing advances and discoveries made by robotic missions, robots are no substitute for human exploration. It is thought that humans could have conducted the same amount of research that the Mars rovers have within a few days or weeks, compared to the several years that it has taken. However, human space exploration warrants further discussion as there are many difficulties that we need to overcome before travel into interplanetary space will be safe enough, never mind the spiralling costs.

East Anglia’s Giant Purple Blob

     

This is a guest post by Luke Surl, a PhD student in the Centre for Ocean and Atmospheric Sciences (COAS) at the University of East Anglia, where he is researching the atmospheric chemistry of volcanic plumes. You can find him on Twitter, or visit lukesurl.com for his excellent science-inspired comics. 

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Last week a giant purple blob descended upon East Anglia, with commotion and a flurry of newspapermen in its wake. The vulnerable were told to shelter in their homes, powerless to tackle its all-pervasive reach. Wisdom was sought from the sages of this ill-understood art, but all that could be done was hope the blight would soon pass.

Smog over Norwich (iWitness24)

A little dramatic license is appropriate for a guest blog, no? To decode, the purple blob is the region of “Very High” air quality risk shown on the official maps that have been appearing this week. These maps have been accompanied by warnings for asthmatics and others sensitive to such conditions. The “sages” are the atmospheric scientists who, normally eclipsed in the media spotlight by their climatic colleges, have been ubiquitous on in the media.

If you haven’t been keeping track, in short a combination of factors conspired this week to cause parts of Britain to experience an usually high level of particulate matter. Britons were breathing dust blown in from the Sahara, plus some with old-fashioned home-grown pollution. The weather slowed the dispersion of this event causing it to linger and intensify.

While “smog” seemed to be the media’s favoured term for the phenomenon, (evoking memories of the London smog of 1952) the discussion amongst the atmospheric scientists at UEA (where I do research) was of the aerosol counts. “Aerosol” is a catch-all term for solid and liquid particles suspended in air, and there are, critically two sorts. We deem primary aerosol particles directly emitted to the atmosphere whilst secondary aerosol are particles which form in-air from gaseous beginnings

The Saharan dust we have been inhaling is primary. Secondary aerosol is most readily created when the air has been polluted with sulphur and NOx. On an ordinary day, road traffic is the biggest such aerosol offender. In London, one of the principle raison d’etres of the congestion charge is to prevent such an air quality hit in a concentrated metropolis of cars and people.

Such technical distinctions are, however, largely ignored by ones lungs. Particles smaller than 10 micrometers in diameter travel into the lungs. The smallest of these can end up penetrating and settling deep into the respiratory system. This is not good news for anyone, especially asthmatics and others with similar conditions.

In some of the more morbid papers that atmospheric scientists are likely to come across, this air quality impact can be quantified. A 2009 study found Americans living in the most polluted areas can attribute air quality to their lives being about 2.5 years shorter than their cousins in cleaner areas. In China, where the economic boom has been quite literally dulled by thick smogs in its cities, the numbers are quite terrifying.  These numbers are difficult to process. They are cold, dispassionate and cryptic, buried in journal papers few will read. But every data point hides an individual tragedy of a life extinguished early

Thankfully Norwich and London are nowhere near Chinese levels, though there are still thousands of such deaths a year. Britain, and the EU in general, quite rightly holds itself to very high standards with regards to its air.

As in everything, the recent incident has had a political dimension. Public debate has asked whether this incident is to be blamed on natural or human causes.

This misses the point. While the primary aerosol from the Sahara and the directions of the winds are beyond the remit of any public policy. But this natural phenomenon is compounded by human action. Regardless of how we apportion the blame, the particulates owing its existence to our cars and factories isn’t made harmless or insignificant by their natural counterparts, rather they can make a bad problem worse, especially for the most vulnerable. And even when the winds change and the purple blobs and media disperse, this pollution can still chip away days, months or years from human lives.

There’s nothing more essential to human life than the air we breathe, which is partly one of the reasons I have chosen atmospheric science as my field of research. It’s also fundamentally something we cannot help but share with our neighbours and community. Our air’s pollution and perturbation, from nature and from man, is something that will impact us all.

The Null Hypothesis: When Do We Declare a Barren World?

This is a guest post by Euan Monaghan, a post-doctoral researcher in the Department of Physical Sciences at The Open University, where he studies the habitability of the subsurface of Mars. You can find him on Twitter

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Astrobiology is the search for life elsewhere in the universe. When this search is focussed on a specific world, there’s a chance—quite a good chance it would seem—that this search will turn out to be fruitless; that there will be no life to be found except the terrestrial life we bring along with us in the process. But can we ever say for sure?

This piece is focussed on Mars, but the idea applies to all worlds targeted for astrobiological exploration. The particular habitats on Europa, Titan or Kepler-62e might be different to those found on Mars, but the question is the same everywhere: does this world host life?

Scientific progress has made the martians of our imagination progressively smaller and more insignificant. No longer the grand canal builders of old—no longer even considered to be multi-cellular—the optimistic amongst us imagine microbes in briny pockets kilometres beneath a hostile surface; their presence deep underground given away by a subtle disequilibrium in the gases of Mars’ tenuous atmosphere. If the martians are there, they’re in hiding.

As we gain a greater understanding of the geologic and climatic history of Mars, a subterranean biosphere doesn’t seem so unreasonable. While Mars was likely warm and wet long before the Earth was, it is also smaller and so cooled faster. It couldn’t hold onto a thick, warming atmosphere for long and so its surface water was gradually lost, both out into space and down into the planet’s interior, to be fixed within the structure of minerals, frozen as permafrost or trapped in groundwater aquifers beneath layers of ice. And as Mars cooled and the water descended, so did the planet’s habitable zone, until it was hidden from view.

Recurring slope lineae in Coprates Chasma may be due to active seeps of water; a clue to a possible subsurface biosphere? (Credit: NASA/JPL/University of Arizona, HiRise)

The habitability of any extra-terrestrial environment is estimated through the study of life adapted to extreme conditions on the Earth. This ‘envelope of life’, with its upper and lower boundaries of temperature, pressure, salt tolerance and so on, is expanding all the time. The relatively recent discovery of our own deep subsurface biosphere, as well as its remarkable diversity and extent, has broadened our concept of what we consider to be a habitable environment. It is with this ever-more subtle knowledge of our own world that we turn back to the planets in our search for life.

The next logical step in that search, for Mars at least, is a detailed study of its atmosphere. In early 2016 the European Space Agency will launch a mission to do just that: the ExoMars Trace Gas Orbiter (TGO) will perform a more comprehensive inventory of the martian atmosphere and the respective abundances of its gases than ever before. It is hoped that the results of this study will provide an insight into active processes occurring deep underground. But then again there is the very real possibility that the TGO will arrive in orbit and find no signs of life, however tentative. The null hypothesis—Mars is a barren world—would still stand. Should we then give up on our search, or do we commit time and resources to a strategy of ever more sophisticated astrobiological exploration, all the while striving to prevent accidental contamination by terrestrial life?

The inevitable moments when we decide to re-focus our search for life beyond the Earth should not be considered moments of pessimism. The universe has too much potential.

Lost in Space: Finding a Sense of Place in the Cosmos

This is a guest post by Sean McMahona PhD student in the School of Geosciences at the University of Aberdeen. Sean’s research applies geological perspectives and techniques to astrobiological problems ranging from the origin and distribution of life in the universe to the origin of methane in the Martian atmosphere. Visit his excellent blog, Fourth Planetfor more on his research, his impressive space art and photography, and writings.

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“Though a planetary perspective is a magnificent and enriching thing, places, not planets, are the core of human experience. It is from places that we build our world.”

—    Mapping Mars, Oliver Morton (2002)

“He stood thereby, though ‘in the centre of Immensities, in the conflux of Eternities,’ yet manlike towards God and man; the vague shoreless Universe had become for him a firm city, and dwelling which he knew.”

—    The French Revolution: A History, Thomas Carlyle (1837)

Last year, in a car park in Aberdeen, I saw Jupiter through a telescope for the first time. What I saw was not the familiar red-spotted giant from the Nasa photographs, that great bronze bauble marbled with cream like artisan coffee—no. What I saw, through a gap in the Scottish clouds, was a pale round smudge with three white specks for moons. It was not dramatic but it was a strange and lovely moment. It reminded me that Jupiter, the other planets, and even the distant stars and galaxies, are no less real, no less here—albeit further away—than Scotland, clouds, car parks, and me. They are on the same map, sharing our geography, our humdrum commonplace reality.

In our eagerness to be inspired by astronomical imagery, we are often tempted to forget this fundamental sameness. Documentaries about the cosmos besiege us with spectacular graphics, rousing orchestral music and rapturous, lyrical narration. In the tradition of Carl Sagan, we are urged to adopt a “cosmic perspective”, in which the Earth dwindles to an insignificant1 “mote of dust suspended in a sunbeam”. Meanwhile, digital space art is reliving the Romanticism of 19th Century painting: balance, proportion and subtlety are abandoned in favour of vertiginous perspectives, extremes of colour and contrast, and sublime, mystical lighting: silhouetted planets disintegrate into vast purple nebulae bristling with crepuscular rays. Thus, it seems that an ecstatic, almost mythical vision of outer space, emphasizing above all its spiritual and aesthetic grandeur, has taken root in popular culture.

McMahon juvenilia. This is what I thought space looked like when I was 17. I have since changed my mind.

McMahon juvenilia. This is what I thought space looked like when I was 17. I have since changed my mind.

Maybe that vision has some role to play in attracting public interest to the space sciences. But paradoxically, it can make the “wonders of the universe” seem less accessible than ever; profound, ethereal, miraculous, even unreal. It bolsters the popularity of astrology by reinforcing the illusion that planets and stars are unfathomable, heavenly beings: much more plausible aids to divination than ordinary material things. Most worryingly, it can give the impression that space exploration is an esoteric spiritual quest, unrelated to ordinary human problems and unfit for serious attention from media, government or young, career-minded scientists.

Perhaps the “numinous” view of space reflects a deeper failure to grasp the implications of the Copernican Revolution. Somehow, I suggest, we still make some kind of basic ontological distinction between the heavens and the Earth2. Consequently, we are unable to feel truly embedded in our extraterrestrial environment, which remains a transcendent, detached and coldly beautiful space rather than a homely, material, lived-in place. The Apollo programme helped to bridge that gap for a generation, transforming the moon from an icon of celestial indifference into a humanly intelligible landscape—rather like a golf course, in fact, replete with bunkers, buggies, flags and footprints3. Revealingly, many people today find it easier to believe that the whole thing was a hoax.

A Summer 2012 photograph by NASA's Curiosity rover inside Gale Crater on Mars.

A Summer 2012 photograph by NASA’s Curiosity rover inside Gale Crater on Mars.

The sharp, vivid photographs taken by NASA’s Curiosity Rover can have a similar effect, reminding us that the martian surface is a real place, not so different in appearance from the rocky deserts of Libya or the High Arctic. Despite our unsophisticated cultural relationship with outer space—a mixture of mythology, indifference and reverence—a crewed mission to Mars in the next thirty years now seems very likely. I hope that mission will allow the next generation to feel more at home in the universe, more fully at ease with the fact that even Milton Keynes4 is part of the Milky Way. What we stand to gain is not an exalted “cosmic perspective” but simply a richer, more expansive sense of place, of where it is that we live our lives.

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1     This strain of rhetoric characteristically fails to observe that human beings adjudicate the significance of the universe, not the other way around.

2      Douglas Adams exploited this confusion to humorous effect, juxtaposing ordinary things with cosmic phenomena: the “restaurant at the end of the universe,” the “whelk in a supernova” and so on; “you may think it’s a long way down the road to the chemist but that’s just peanuts compared to [the size of] space”.

3      Some readers will know that the American astronaut Alan Shephard did in fact play golf on the moon; two golf balls remain there.

4       Milton Keynes is an architecturally unprepossessing English town and home to the Open University, where much British space research has been conducted.