NExSS Coalition: The Power of Collaboration

The search for life beyond Earth is an endeavour that has always fascinated me, thus I was immensely excited to learn, recently, that “NASA is bringing together experts spanning a variety of scientific fields for an unprecedented initiative dedicated to the search for life on planets outside our solar system” (1). The Nexus for Exoplanet System Science (“NExSS”) is a wide-scale interdisciplinary initiative that will target extrasolar planets that have the greatest potential for supporting life (2) (3). My only concern is one that is shared by the National Research Council:

“The natural tendency toward terracentricity requires that we make a conscious effort to broaden our ideas of where life is possible and what forms it might take. The long history of terran chemistry tempts us to become fixated on carbon because terran life is based on carbon. But basic principles of chemistry warn us against terracentricity. It is easy to conceive of chemical reactions that might support life involving noncarbon compounds, occurring in solvents other than water, or involving oxidation-reduction reactions without dioxygen” (4).

For me, the greatest discovery would be what Dr. Chris McKay calls a “second genesis” or genuine “alien life” (5). I covered this topic in an article a while ago (6). Basically, if we are searching for life only as we know it, we may miss something completely off our proverbial radar, so it is important to maintain an open mind about the broad possibilities regarding life.

If you want to support space science and exploration in general, visit Penny4NASA and The Planetary Society to learn more about how you can become a space advocate.

Twitches of the Cosmic Line: Exoplanets, Habitability and the Outer Limits of Biochemical Potential

The relentless pressures of survival have shaped the panoply of life on Earth throughout the ages. Life has endured oppressive heat, extreme volcanism, deep freezes, vicious asteroid impacts, perhaps even gamma ray bursts, and multiple mass extinction events. Yet, as resilient and adaptive as biology has proven, every organism that has ever been, owes its existence to a delicate game of cosmic chance. The Earth orbits within a slender ‘habitable zone’ – a ‘slice of Eden’ – around the Sun, which, in spite of the aforementioned pressures and catastrophic events, has provided the foundational conditions for life to burst forth and flourish within a relatively narrow cosmic timeframe. As far as we know, Earth is the only place where this has occurred, but evidence is mounting that many extrasolar worlds enjoy similar blessings from their star.

The quest for extrasolar planets (‘exoplanets’) is one of the most rapidly developing fields in Astronomy. Hundreds of exoplanets have been confirmed since the mid 1990s and there are thousands of current candidates, with Astronomers now confidently predicting billions more worlds within the Milky Way Galaxy alone (including many within the classic Circumstellar Habitable Zone). Furthermore, perspectives about what exactly may constitute ‘habitability’ – or even life – in various contexts are broadening, whilst new evidence indicates that DNA building blocks can be created in space. The notion that the Earth alone harbours life amongst this vast spectrum of potential, grows ever more unlikely.

The history of planet hunting is littered with false hope, frustration and suspicion. In his groundbreaking book, The Neptune File, Tom Standage explains that, “by the early 1990s planet hunting was seen as a somewhat disreputable field of astronomy. Funding to search for planets around other stars was extremely difficult to come by; astronomers involved in the field were regarded with suspicion. But still they searched.” Since exoplanets are distant, faint and overwhelmed by the luminosity of their star, they cannot be observed directly – at least not yet – and must instead be deduced by indirect means. Despite numerous painstaking detection attempts and discovery claims, perhaps most famously by Peter van de Kamp in the 1960s, subsequent studies were unable to provide verification. Most recently, in van de Kamp’s case, Choi et al. (2013) used precise doppler measuring to put the matter to rest. “Previous claims of planets around the star by van de Kamp are strongly refuted,” the authors state. In the early 1990s, however, astronomers finally struck ‘exo-gold’.

In 1992, using the Arecibo Observatory in Puerto Rico, Wolszczan & Frail reported planetary bodies orbiting pulsar PSR1257 + 12 with “almost circular orbits with periods of 98.2 and 66.6 days”; and in 1994, Wolszczan once and for all confirmed, “irrefutable evidence that the first planetary system around a star other than the sun has been identified”. Disappointment followed, as this was no environment suitable for life. Supernova remnant pulsars would pump high energy radiation into their surrounding bodies, lashing at anything that constitutes an atmosphere; and/or bathing a barren surface in lethal x-rays. The meticulous search for a system more suitable to habitability as we know it, continued, bolstered by a new confidence in planet detection methodologies and improving technology. Observers did not have to wait long. In 1995, the loosened floodgates of discovery were flung wide open, following radial-velocity confirmation by Mayor & Queloz of a planet orbiting Sun-like star 51 Pegasi. Subsequent observations by other research teams demonstrated an “excellent” agreement with the work of Mayor & Queloz. Whilst this close-orbiting planet’s estimated 1,000+°C surface temperature would most certainly ruin your day at the beach, its discovery marks the first ever confirmation that Sun-like stars do host planets. This led to a heightened emphasis on what may be considered the ‘holy grail’ of exoplanetology – the search for Earth-like planets around Sun-like stars. In fact, the tagline for NASA’s Planet Quest initiative is, “The Search for Another Earth”.

Our Sun is a G-type main-sequence star, halfway through its 10 billion year main sequence lifetime. It has nourished our planet long enough for life to evolve to its current state. Our planetary neighbours, on the other hand, do not fare so well. Closer to the beast, Mercury fluctuates between a scorching 427°C and a chilling -179°C; whilst Venus maintains temperatures high enough to melt lead. Farther out, the Sun gives a merciless cold shoulder. Mars has a temperature range of -87°C to -5°C and that’s where any semblance of ‘warmth’ ends (although Earth could theoretically remain habitable at Mars orbit, due to its higher gravity, plate tectonics and magnetic field, which Mars lacks). Earth’s atmosphere and position between the two extremes is, at the present time, perfect for life as we know it, yet the balance is tenuous and finite. Natural or human-induced catastrophes, in the short-to-mid term, could threaten habitability (at least, in the human context); whilst in the long term, the Sun will inevitably roast Earth like a marshmallow, as it expands into its red giant phase. Determining the likely habitable zones of exoplanets is a complex exercise, with a multitude of variables to consider alongside contemporary technological limitations. However, recent research into a particular class of planetary system candidate has vastly increased the likelihood that small rocky worlds, orbiting relatively favorable stars, may be the galactic norm. The planetary systems in question orbit a class of stars known as M dwarfs (or red dwarfs) – faint, cool, long-lived and abundant stars within the Milky Way. Astronomers estimate that hundreds of billions of planets orbit M dwarf star systems within our galaxy alone, with tens of billions of these residing in the habitable zone.

Since M dwarfs are much fainter and cooler than our Sun, their calculated habitable zones are much closer in comparison to Earth’s habitable zone. This leads to important caveats. For instance, these stars have a tendency towards stellar eruptions and significant magnetic fields, which may bathe their close inner habitable zone planets in X-rays and UV radiation. Furthermore, as Vidotto et al. (2013) propose, M dwarf magnetic fields may reduce the size of planetary magnetospheres, leading to atmospheric erosion by stellar winds; whilst Barnes et al. (2012) postulate that tidal heating may produce runaway greenhouse effects for certain planets within the habitable zone, thus significantly reducing habitability. Nevertheless, Delfosse et al. (2012) reiterate that “M dwarfs have been found to often have super-Earth planets with short orbital periods,” which makes them “preferential targets in searches for rocky or ocean planets in the solar neighbourhood”. In fact, Tarter et al. (2007) suggest that evolutionary challenges, such as stellar flaring, may not be as prejudicial as generally assumed, thus, they conclude, “it makes sense to include M dwarf stars in programs that seek to find habitable worlds and evidence of life”. It is this potential that makes these M dwarf star systems intriguing, especially when considered within the context of their sheer multitude throughout the galaxy.

Jon Swift is a postdoctoral researcher at the California Institute of Technology. He works in Professor John Johnson’s ExoLab group, which hunts for, and characterises extrasolar planets. Swift’s current focus is on the formation and evolution of planetary systems. In late 2012, Swift, Johnson and co-authors submitted a paper – Characterizing the Cool KOIs IV: Kepler-32 as a prototype for the formation of compact planetary systems throughout the Galaxy – that garnered significant public attention. Using the Kepler space telescope, the research team took advantage of the rare edge-on orientation of the Kepler-32 system (in relation to the orbiting observatory) to study its five planets in unprecedented detail, as they take turns at blocking their star’s light. The Kepler-32 M dwarf system is incredibly compact. Its planets orbit within an equivalent range to one third that of Mercury’s around our Sun (Swift et al. propose that the planets formed at wider orbits, migrating inwards over time). Although, apart from its coincidental orientation, the system is not unusual, and this is what makes it extraordinary in its implications.

In a seminal estimation, the authors used this representative M dwarf system to infer that a staggering number of planets populate this most common of star systems throughout the galaxy. Shortly after its publication, Swift, as lead author of the Astrophysical Journal paper, explained that “basically there’s one of these planets per star” in the Milky Way. Given that there are a hundred billion stars or more in our galaxy, these numbers are overwhelming, but, as Swift also pointed out, the team’s probability calculations were conservative. If the dataset were expanded, the average would likely be doubled. With countless numbers come countless opportunities. With this in mind, I followed up with Dr. Swift (via email) to discuss the possibility of favourable conditions for life on planets orbiting M Dwarf systems; and how his team’s unique calculations may allow for additional speculation on this issue:

“Indeed M dwarfs do have temperate zones around them in which liquid water could potentially exist. These zones are both closer in and span a narrower range in orbital radius than for stars like the Sun. But they do exist, and it is expected that there are many planets throughout the Galaxy that lie in these temperate regions around M dwarfs. M dwarfs are also known to harbor rocky planets, so it is quite feasible that there are rocky planets with liquid water around M dwarfs. But the prevalence of this specific kind of planetary system is not yet known… The high frequency of planets around M dwarfs makes it easier for life to spring up across the Galaxy, simply because there are more places that it would have had a chance to begin. However, without knowing how difficult it is for life to begin from inanimate matter, we are still a long ways away from being able to deduce an accurate likelihood of life elsewhere in the Galaxy”.

He also cited the work of Tarter et al. (2007), noting that, “while there may be some difficulties in creating or sustaining life on planets around M dwarfs (even in the “habitable zone”), they are viable locations for the development and evolution of life; perhaps even intelligent life”. Swift’s clarifications raise some of the most profound questions of all – how did life begin on Earth? and how may it arise, survive and thrive elsewhere? If there is one thing that the study of M dwarfs and other planetary systems has shown, it is that if life were to arise elsewhere in the Universe, it certainly has a vast and diverse number of orbiting outposts from which to launch its biochemical journey. As previously discussed, much of the focus in planet hunting centres around finding planets as favourable as possible to life as we know it – lots of liquid water; a solid surface; and a favourable orbital zone around a star without a temperament too much like The Incredible Hulk on a rough day. Why?

Part of the answer is terracentricity. We search for what we know, and what we know shapes what we expect. Since the only examples of life we have to go by are those found on Earth, we naturally gravitate towards as much “Earth-likeness” as we can deduce elsewhere. The most obvious manifestation of this human tendency is the search for ‘classic’ habitable zone exoplanets. Logically, this approach is sound. As we know, we cohabitate a planet utterly teeming with stunning biological diversity. The imagination need not overstretch to consider a similar situation elsewhere, given similar conditions. However, there are good scientific reasons to make conceptual leaps beyond the terracentric frame of reference; and when exoplanetology meets astrobiology along these lines, intriguing biochemical/evolutionary vistas present themselves for consideration. “The natural tendency toward terracentricity (a particular set of biological and chemical characteristics that are displayed by all life on Earth) requires that we make a conscious effort to broaden our ideas of where life is possible and what forms it might take,” explains the National Research Council (NRC). “The long history of terran chemistry tempts us to become fixated on carbon because terran life is based on carbon. But basic principles of chemistry warn us against terracentricity”.

In 2007, the Council’s Committee on the Limits of Organic Life in Planetary Systems, produced a landmark review of the scientific literature, aimed at broadening perspectives about the full potential of life, and focusing future astrobiological research accordingly. The Committee was candid about the sometimes deep limitations of current knowledge (even in relation to most microorganisms in Earth environments), although what is known and what can be reasonably speculated upon, constantly redefines the boundaries of possibility. The study of the potential origins, distribution and biochemistry of life raise the most profound, fundamental, challenging and exciting questions facing humanity today. At present, Earth life is the only form of life and biochemistry we know, but we don’t know how it began. It may have begun in deep sea hydrothermal vents, or perhaps was seeded via panspermia (interplanetary transfer of microorganisms). The latter of these possibilities was considered of high importance by the committee, for if Earth was seeded in this manner, a fundamental biochemical resemblance to other lifeforms could be expected elsewhere in the galaxy; and it could be expected to thrive in a wide variety of extreme environments. However, the committee strongly concluded that “life is possible in forms different from those on Earth” and that these may be highly unusual:

“As discussed in the literature, chemical models of non-Earth-centric life reveal much about what the scientific community considers possible, particularly regarding ways in which systems organize matter and energy to generate life. Thus, truly “weird” life might utilize an element other than carbon for its scaffolding. Less weird, but still alien to human biological experience, would be a life form that does not exploit thermodynamic disequilibria that are largely chemical. Weirder would be a life form that does not exploit water as its liquid milieu. Still weirder would be a life form that exists in the solid or gas phase. In a different direction, yet also outside the scope of life that most communities think possible, would be a life form that lacks a history of Darwinian evolution”.

One thing, above all, which life on Earth at least has taught us, is that once it secures a foothold, it is nigh impossible to eradicate. Assuming the forces of evolution are in play, life’s march forward will be relentless and far-reaching, across a diverse range of environments over time. Even the most original science fiction writers of the past – and perhaps even today – would be hard pressed to have imagined the extreme lifeforms that have been found on Earth to date, let alone those potentially awaiting discovery elsewhere. Consider, for example, the enigmatic Deinococcus radiodurans – cited as the World’s Toughest Bacterium – especially for its ability to withstand a thousand times more radiation than humans. Deinococcus radiodurans defies the ‘Humpy-Dumpty’ analogy; extreme doses of ordinarily lethal radiation shatter its genome, then it puts itself perfectly back together again.

In addition to long-surviving spore-forming bacteria, radiation-resistant microorganisms such as Deinococcus radiodurans are considered so tough, they may even be legitimate candidates for surviving space travel and seeding other worlds, especially if embedded in rocks and ejected. According to Dr. Stephen Kane of San Francisco State University, “there have even been studies performed on Earth-based spores, bacteria and lichens, which show they can survive in both harsh environments on Earth and the extreme conditions of space”. However, the transference of life itself may not have been necessary to lay the foundations for life to spark on Earth. It is plausible, as noted by Chyba et al. (1990), and Chyba & Sagan (1992), respectively, that, “Earth accreted prebiotic organic molecules important for the origins of life from impacts of carbonaceous asteroids and comets during the period of heavy bombardment 4.5 x 10(9) to 3.8 x 10(9) years ago”, or that “organic synthesis [was] driven by impact shocks; and… other energy sources”. In 2007, the National Research Council’s Task Group on Organic Environments in the Solar System acknowledged that, “a remarkably broad range of organic compounds has been identified in carbonaceous chondrites,” stating categorically, “the presence of such compounds in meteorites indicates that impacts by meteorites, comets, and dust must have delivered potentially biologically useful organic compounds to early Earth and the other terrestrial planets”.

In 2012, a research team from Goddard’s Astrobiology Analytical Laboratory reiterated, “Meteorites may have served as a molecular kit providing essential ingredients for the origin of life on Earth and possibly elsewhere”. “For the first time,” explained Dr. Michael Callahan, lead author of the 2011 study that examined Carbonaceous meteorites, “we have three lines of evidence that together give us confidence these DNA building blocks actually were created in space”. Researchers were previously much less certain whether these DNA components were actually created in space, but Callahan et al.’s findings strongly support an extraterrestrial origin. Glavin et. al. (2012) examined nonterrestrial amino acid excesses in the Tagish Lake meteorite and concluded, “significant enantiomeric enrichments for some amino acids could form by abiotic processes prior to the emergence of life”; and whilst Pizzarello & Shock (2010) acknowledge the high degree of uncertainty surrounding the possibility of biogenesis after exogenous delivery, they maintain, “the selective abundance of biomolecule precursors evident in some cosmic environments and the unique L-asymmetry of some meteoritic amino acids are suggestive of their possible contribution to terrestrial molecular evolution”.

The growing awareness of the extent of this type of transference of material – when considered alongside increasing evidence of the poly-extremophilic potentialities of certain organisms, and the possibility of alternative biochemistries and geneses – inevitably leads to the continuing reassessment of ‘habitability’. In turn, this evolving broad spectrum understanding helps to refine the parameters and technologies of future missions. If life has been been found to survive in environments previously considered unimaginable, on Earth, it is plausible that such life may have – or may still – exist on worlds outside the classic Circumstellar Habitable Zone. Whilst the possibilities for extrasolar planetary systems in this context may be almost endless, the logical and only practical first place to search for such evidence, is in our own Solar System. For this reason, the 2011 Decadal Survey, Vision and Voyages for Planetary Science in the Decade 2013-2022, lists moons like Europa, Enceladus, and Titan as top research targets:

“What were the primordial sources of organic matter, and where does organic synthesis continue today? The surfaces and interiors of the icy satellites display a rich variety of organic molecules—some believed to be primordial, some likely being generated even today; Titan presents perhaps the richest planetary laboratory for studying organic synthesis ongoing on a global scale. Europa, Enceladus, and Titan are central to another key question in this theme: Beyond Earth, are there modern habitats elsewhere in the solar system with necessary conditions, organic matter, water, energy, and nutrients to sustain life, and do organisms live there now?”

Whilst viable missions to answer these questions are currently of a robotic nature, longer term goals include human missions to Mars, the Moon and beyond. As human missions carry a greater risk of contamination, it has been said that, “nothing would be more tragic in  the… exploration of space than to encounter alien life and fail to recognize it either because of the consequences of contamination or because of the lack of proper tools and scientific preparation”. For this reason, future research will also focus on better understandings of life and habitability as demonstrated by Earth life, and will continue to consider possible biological alternatives beyond the terracentric frame of reference.

Dr. Isaac Asimov once likened the joys of scientific inquiry, as it moves through history, to a man rising at dawn to fish, waiting happily all day for the occasional twitch of his line. Wouldn’t it be more practical for him to order all the fish he wanted from the fish market, via telephone?, Asimov asks. Perhaps, but the true joy is in the process of awaiting those elusive twitches. Within the context of the current discussion, merely knowing how much we don’t know about life’s origins, structures, and potential distribution throughout the Cosmos, makes the anticipation of what we may yet discover – the vast potential of what could be out there – all the more exciting.

In summary, we know there are potentially hundreds of billions of extrasolar planets, just in our Galaxy alone; and that many of these may fit the current precepts of classic habitability. We know there are countless interplanetary objects that have spread the organic building blocks of life in all directions through space; and perhaps even life itself. We know that the type of life to which we have become accustomed ranges from extreme fragility to extreme resilience; and that virtually nowhere on Earth does life not exist. We also know that life has survived at least five mass extinction events throughout our planet’s history. We don’t know exactly how life began on Earth, how common it may be throughout the Galaxy, what form it may take, or how it may spawn from world to world. In the future, we may not always know where or how to search for life elsewhere, or how long we may take to find it – or even if we ever will – but the tantalising prospect of those occasional twitches at the end of the line, will make for an enjoyable day at the lake.

Daniel Zalec | awesomeastronomy.com

The Aftermath of Genesis: Quasars Light the Way

The discovery of ‘quasi-stellar radio sources’ in 1963 (abbreviated as ‘quasars’ in 1964 by Hong-Yee Chiu) sparked a paradigm shift in our conceptual understanding of the universe. One of the most important realisations brought about by quasar research is that black holes are more than theoretical constructs theorised by John Michell in 1783 and later predicted by Einstein’s theory of General Relativity; they are actually real objects of immense practical significance in the evolution of the universe. The scientific questions raised by the study of quasars have pushed the boundaries of observational astronomy technologies, stretched the human imagination about deep cosmological time, and elucidated the conditions of the early universe. Maarten Schmidt’s seminal 1963 paper in Nature, 3C 273: A Star-like Object with Large Red-shift, ultimately led to an “outburst of theoretical work on black holes and observational attempts to detect them,” as noted by Stephen Hawking (The Universe in a Nutshell, p. 113). Since the luminosity of quasars is so incredibly powerful and concentrated within a relatively small region of space, it seemed that black holes were the only possible explanations for such energy. It is now accepted that larger quasars are bi-products of supermassive black holes (SMBH’s) – many millions of star masses worth – which gobble and superheat enormous amounts of matter to indulge their insatiable gravitational hunger.

Quasars can emit as much energy per second as a thousand or more galaxies, making them the most intense X-ray and visible light sources known to science. The superheated matter forms in an accretion disc and is slowly devoured by the black hole. If the conditions are right within the immediate environment, collimated streams of magnetized plasma (‘relativistic jets’) can shoot out over a million light years into space, at velocities close to the speed of light. Hayashida et al. (2012) clarify that these jets originate from the “conversion of the gravitational energy of matter flowing onto the black hole to the kinetic energy of the relativistic outflow or tapping the rotation energy of a spinning black hole.” A Quasar is the ‘Achilles of the Cosmos.’ Its monster black hole quickly swallows surrounding matter into oblivion, ensuring a relatively short but glorious existence. Their photons are their legacy. As Carl Sagan once explained, “when we observe distant quasars 5 billion light years away, we are seeing them as they were 5 billion years ago, before the Earth was formed. (They are, almost certainly, very different today)” (Pale Blue Dot, p. 23). As Sagan had previously speculated, the farthest quasars may be 10 or 12 billion light years away (Cosmos, p. 260). In fact, as we now know, the most distant quasar, ULAS J1120+0641, is almost 13 billion light years from Earth (redshift z = 7.085). These multi-billion year-old quasar photons originate from a time less than a billion years after the Big Bang.

True to their enigmatic background, quasars still inspire intense scientific investigation. They hold the key to better understandings of the early universe. This drives researchers to develop ever more precise observational technologies, designed to advance the debate surrounding quasar-induced galactic development; examine physics under extreme (‘relativistic’) conditions; and to one day directly observe the immediate environment of a black hole (a long held objective of astrophysics). In 2012, the latter of these goals advanced markedly. On July 18, an international team of astronomers announced that research data, gathered by an intercontinental network of submillimetre wavelength radio telescopes, allowed them to observe a quasar five billion light years from earth – with a clarity two million times that of human vision. The observation of quasar 3C 279 was the sharpest direct observation of the centre of a distant galaxy ever made. This observation holds substantial implications for the future of supermassive black hole imaging. Quasar 3C 279 draws its energy from a supermassive black hole one billion times more massive than the Sun, and the accuracy of this latest observation (to within 0.5 light years of 3C 279’s nucleus) is considered “quite remarkable” by scientists from the Max Planck Institute for Radio Astronomy, who led the historic research effort (in association with the Onsala Space Observatory and the European Southern Observatory).

Very Long Baseline Interferometry (VBL) was used to link three telescopes for joint observation: The Atacama Pathfinder Experiment Telescope (Chile), the Submillimetre Array (Hawaii), and the Submillimetre Telescope (Arizona). These three instruments had never been connected in such a way. Observations were made in radio waves with a wavelength of 1.3 millimetres. As noted by the astronomers, this is “the first time observations at a wavelength as short as this have been made using such long baselines.” With VBL, the longer the “baseline” (i.e. the distance between each telescope), the sharper the observation – akin to casting the proverbial “wide net.” The baselines for the observation of quasar 3C 279 on 7 May 2012 were: 9447 km (Chile to Hawaii), 7174 km (Chile to Arizona), 4627 km (Arizona to Hawaii). The resulting angular resolution was of 28 microarcseconds – or, 20/20 vision, times two million. Within the next decade or so, astronomers aim to utilise an extensive array of radio telescopes, up to fifty, to create what is known collectively as the “Event Horizon Telescope” – a long-term international collaborative project between numerous teams of radio astronomers. The results promised by the Event Horizon Telescope have been a long time coming for observational astronomers, with the prospects for significant advances in knowledge now tantalisingly close at hand. “It would be an amazing thing,” says Daniel Marrone, of the University of Arizona’s Steward Observatory, “it’s never been done before, getting an image of a black hole.” MIT’s Haystack Observatory says, “A long standing goal in astrophysics is to directly observe the immediate environment of a putative black hole with angular resolution comparable to the event horizon. Realizing this goal would open a new window on the study of General Relativity in the strong field regime, accretion and outflow processes at the edge of a black hole, the existence of an event horizon, and fundamental black hole physics.”

Quasars offer the chance for researchers to examine physics under some of the most extreme possible conditions, including the prolific acceleration of particles and production of high energy photons; relativistic gas dynamics, turbulence and plasma processes; the observational effects and illusions brought about by such processes; and potentially exotic forms of matter. Things also get interesting beyond the immediate environment of the feeding frenzy. Astronomers are accumulating a significant body of evidence that suggests quasars played a vital role in the formation of galaxies in the early universe. As noted previously, plasma jets of immense power and reach are a consequence of supermassive black holes. But what is the extent of the influence of these jets on the surrounding intergalactic medium (IGM)? As outlined in Ilana Joanne Klamer’s 2006 PhD thesis, this is an important area of astrophysics that merits further investigation:

“The highly relativistic, supersonic jets that power into the surrounding medium and slam into the existing overdensities can trigger star formation along cocoons surrounding the jets or could modify the stellar initial mass function as a result of the effect of enhanced cosmic ray ionisation in the molecular cores. Therefore, it will also be along these same preferential directions that the first heavy elements — including carbon and oxygen — will be produced as the stars end their lives and enrich their surroundings” (p. 142).

“There is little doubt that relativistic plasma jets from radio galaxies and quasars deposit appreciable amounts of energy into their surrounding IGM. However, debate continues to rage over the jets’ specific influence. Determining the true extent of this influence is an interesting and important question in astrophysics: the ability to trigger large scale star formation in the early universe could finally explain the ‘rapid enrichment’ conundrum in high-redshift radio galaxies and quasars whereby chemical enrichment of the IGM around these sources has taken place on timescales much shorter than predicted by traditional star formation scenarios” (p. 152).

In 2009, Elbaz et al. drew attention to “converging evidence that radio jets may trigger galaxy formation” (p. 1359), whilst highlighting the importance of increasing equipment sensitivity for future observations (p. 1373). More recent evidence published in 2012 by Borguet et al. reveals that energetic quasar outflow – as observed in quasar SDSS J1106+1939 – can indeed reach the necessary power to significantly influence the AGN and therefore galactic formation. According to the research team, “This is the first time that a quasar outflow has been measured to have the sort of very high energies that are predicted by theory… “We couldn’t have got the high-quality data to make this discovery without the VLT’s X-shooter spectrograph. We were able to explore the region around the quasar in great detail for the first time.” This is yet another example of quasar research driving developments in radio astronomy technology. In fact, the Very Large Array (VLA) in New Mexico, one of the world’s premier astronomical radio observatories, was built to observe quasars with optical resolution.

Whilst radio astronomy has generated an incredible wealth of high angular resolution data on galactic nuclei, quasars and pulsars over the past few decades, numerous challenges will need to be overcome in order for radio astronomy to remain on the forefront of discovery over the next few decades. Ekers & Bell (2000) cite unprecedented international cooperation and joint mega project funding as fundamental realities for future projects – along with the need to ensure extensibility of past and present technologies, overcoming orbital and terrestrial interference, plus dealing with issues of funding and government policy. To address the inherent limitations of Earth-based observation and orbital interference, more radical, long-term solutions are being developed. For example, the Lunar Radio Array (LRA) project aims to make surface-based radio telescope observations from the dark side of the Moon, focusing on the highly redshifted line of the spectrum. The ultimate mission goal: Nothing short of conquering one of the last frontiers of Cosmology – the Dark Ages – the edge of Genesis, when the first stars were being formed.

As Ekers & Bell noted, the entire radio spectrum is needed for redshifted lines; and according to the LRA team, “The far side of the Moon is likely the only site in the inner solar system for exploiting this potential fully as significant obstacles exist to ground-based telescopes, including heavy use of the relevant portion of the spectrum by both civil and military transmitters and distortions introduced by the Earth’s ionosphere.” The LRA would also answer fundamental questions about the formation and influence of the first black holes, and obviously, quasars. The potential offered by the observational purity of space has been described as “limitless.” For this reason, the future of observational astronomy will edge inevitability closer to the stars. However, it will always be remembered that those perplexing objects of impossible brilliance, the quasars, lit the way.

Daniel Zalec | awesomeastronomy.com

Heavens for Pennies: Voyager’s Enduring Legacy

As NASA’s Voyager spacecraft explore the outer boundaries of the Solar System, transmitting vital data across billions of kilometres to the antennas of the Deep Space Network, their pioneering legacy throws into sharp relief a disturbing reality. The forces of political and economic expediency, along with lurking indifference are threatening the grand human adventure of the Solar System and beyond. In the wake of a second year of proposed brutal budget cuts for NASA’s Planetary Science Division, Voyager 1’s impending date with the stars will be more than just a shift in cosmic ray and magnetic field patterns. This landmark event will serve as a symbol for the spirit of human curiosity, adventure and discovery, as Voyager becomes the first human emissary to the Milky Way.

Dr. Carl Sagan once wrote of the Voyager twins, “They came in at cost, on time, and vastly exceeded their design specifications––as well as the fondest dreams of their makers. Seeking not to control, threaten, wound or destroy, these elegant machines represent the exploratory part of our nature set free to roam the Solar System and beyond” (Pale Blue Dot, 1994, p. 82). For the past few years, both Voyager craft have been making their way through the tempestuous region of space known as the heliosheath. The heliosheath is the relatively narrow band of slowed and heated solar wind between the termination shock and interstellar space, the boundary of which marks the limit of our Sun’s charged particles. Voyager 1 entered the heliosheath in December 2004, followed by Voyager 2 in August 2007. From early 2009 to early 2012, Voyager 1 reported a steady increase in galactic cosmic rays, followed by a clear spike on May 7, 2012, suggesting an historic milestone was close at hand.

In June, Dr. Edward Stone, project scientist for the Voyager program since 1972, stated with excitement, “The latest data indicate that we are clearly in a new region where things are changing more quickly… We are approaching the Solar System’s frontier.” In December, it was confirmed that Voyager 1 had discovered a new region called the magnetic highway, where the Sun’s magnetic field lines connect to interstellar magnetic field lines. Voyager 1 is now truly living on the edge. “Although Voyager 1 still is inside the sun’s environment,” Dr. Stone explains, “we now can taste what it’s like on the outside because the particles are zipping in and out on this magnetic highway.”

Voyager 1, launched on September 5, 1977 from Kennedy Space Centre, is no stranger to attention. In 1990, for instance, the probe’s narrow-angle camera captured one of the most iconic images in space exploration history, now called The Pale Blue Dot. Requested by Dr. Sagan, who demonstrated a keen sense for its poetic implications, The Pale Blue Dot shows the Earth as 0.12 of a pixel amidst the vastness of space – a universal lesson in perspective. Voyager 1 also discovered that one of Jupiter’s many moons, the Galilean satellite Io, is home to eight oxygen and sulfur-spewing volcanoes; and that Saturn’s enigmatic moon, Titan, has a nitrogen-rich atmosphere. Voyager 2, which was launched on August 20, 1977, also made invaluable contributions to knowledge, including magnetic pole analyses of Uranus and the discovery of supersonic winds on Neptune.

All this exquisite knowledge and much more, cost each American citizen less than a penny a year from launch to reaching Neptune (Pale Blue Dot, 1994, p. 82). Even within the heliosheath – the Voyagers are redefining scientific understandings – staying true to their reputation for discovery. Data from both Voyager craft have allowed researchers to create computer models which demonstrate that the previously imagined smooth, streamlined look of the heliosheath is in fact a bubbly region of ‘magnetic foam,’ created by magnetic field compression at the termination shock. Cosmic rays must make their way through this bubbly region before entering our Solar System. Supplementing data from other craft, such as the Interstellar Boundary Explorer (IBEX) and Cassini, Voyager’s Interstellar Mission remains on the cutting edge of space exploration – many years after its Primary Mission ended. Remarkably, Voyager’s computer system is graced with a mere 8,000 bytes of memory.

Whilst inevitably, as noted by Dr. Sagan, both craft are “destined to wander forever in the great ocean between the stars,” the exact moment at which the Voyager 1 probe will officially enter interstellar space remains uncertain. Key indicators are being monitored closely. The increase in galactic cosmic rays is only one of three data indicators that will ultimately confirm an interstellar breakthrough. When Voyager 1 pierces the true edge of the solar frontier, scientists expect intensity readings of energised particles (as experienced within the heliosphere) to drop off.

In addition, they predict the currently East-West oriented magnetic field lines to swing closer to North-South. Although the craft’s present environment is one of considerable magnetic intensity, the direction of the magnetic field lines have not changed. “The magnetic field data turned out to be the key to pinpointing when we crossed the termination shock,” says Leonard Burlaga, a Voyager magnetometer team member, “and we expect these data will tell us when we first reach interstellar space.” Perhaps it is perfect timing that two spacecraft destined to eternally drift apart across the cosmos and whose operational longevity has always been uncertain, remind us of the raw guts and glory of boldly pushing frontiers and satisfying the ingrained human yearning for exploration.

The assault on NASA’s Planetary Science budget seems to be developing into an annual event. The 2013 Budget proposal would have slashed funding for the Planetary Science Division by 20%, including a 39% cut for the Mars Exploration Program. This prompted Dr. Neil deGrasse Tyson, on March 7, 2012 to warn Congress that, “NASA’s Mars science exploration budget is being decimated.” “It has come to this,” Nature reported two months later, “planetary scientists across the United States hawked baked goods to the public… in an effort to drum up awareness of their field’s dwindling financial support.” The elite scientific minds of the world have been reduced to the peddling of cupcakes and washing cars. Equally strong protestations came from other scientists and space advocacy networks, including The Planetary Society, a group co-founded in 1980 by Dr. Sagan.

This combined public pressure (surely aided by the high profile landing of the Mars Science Laboratory Curiosity Rover in August 2012) resulted in Congress restoring $200 million to the final budget of March 2013. Now, the ‘annual assault’ starts all over again with the 2014 Budget, where The White House is launching another raid on the Planetary Science piggy bank, again calling for more than $200 million worth of cuts. According to the Planetary Society’s latest petition, titled Write Congress to Save Our Science, Again, “The White House has doubled down on its efforts to cut Planetary Science at NASA. It’s proposing a cut of over $200 million, despite the fact that Congress rejected a similar cut last year. This will prevent any mission to Europa. It delays for years efforts to send smaller spacecraft throughout the Solar System, and will have long-lasting repercussions on the scientific and engineering community.”

Meanwhile, far away from the political storm, Earth’s most venerable and far-reaching spacecraft, the Voyager twins, continue relaying valuable scientific data after more than three decades of dutiful operation. Each time precious information is shot back to Earth across billions of kilometres of blackness, we are reminded that there is so much more to discover; so much more for which to strive. As Voyager 1 soars towards the edge of interstellar space at 68,000 kilometres per hour, its transmissions still manage to inspire a handful of dreamers, who itch for the moment of interstellar breakthrough. Our knowledge of the Solar System and our place within it has been vastly expanded thanks to two small spacecraft that have traded us the Heavens for pennies.

Savor Voyager’s legacy and everything for which it stands, because the next time you stop at a set of traffic lights, a Planetary Scientist may be squeegeeing your windshield.

Daniel Zalec | awesomeastronomy.com

Sharp Eye on a Distant Hunger Game: Telescope Network’s Quasar Milestone

It can be difficult to comprehend the sheer savagery witnessed in the most extreme regions of the universe. Striking evidence of such violence comes in the form of quasars, the most intense X-ray and visible light sources known to science. Larger quasars are bi-products of supermassive black holes – many millions of star masses worth – gobbling and superheating enormous amounts of matter to indulge their insatiable gravitational hunger. On July 18, an international team of astronomers announced that research data, gathered by an intercontinental network of submillimetre wavelength radio telescopes, has allowed them to observe a quasar five billion light years from earth – with a clarity two million times that of human vision. This is the sharpest direct observation of the centre of a distant galaxy ever made, and the implications for the future of supermassive black hole imaging are significant.

The astronomical object at the centre of all the attention, is bright quasar 3C 279, which draws its energy from a supermassive black hole one billion times more massive than the Sun. The accuracy of this latest observation (to within 0.5 light years of 3C 279′s nucleus) is considered “quite remarkable” by scientists from the Max Planck Institute for Radio Astronomy, who led the historic research effort, in association with the Onsala Space Observatory and the European Southern Observatory. The technique of Very Long Baseline Interferometry was used to link three telescopes for joint observation: The Atacama Pathfinder Experiment Telescope (Chile), the Submillimetre Array (Hawaii), and the Submillimetre Telescope (Arizona). These three instruments had never been connected in such a way. Observations were made in radio waves with a wavelength of 1.3 millimetres: “The first time observations at a wavelength as short as this have been made using such long baselines,” according to the team.

In simple terms, with this technique, the longer the “baseline” (i.e. the distance between each telescope), the sharper the observation. For the observation of quasar 3C 279, the baselines for 7 May 2012, were as follows: 9447 km (Chile to Hawaii), 7174 km (Chile to Arizona), 4627 km (Arizona to Hawaii). The result was an angular resolution, of 28 microarcseconds – or, 20/20 vision, times two million. In the future, astronomers aim to utilise an extensive array of radio telescopes, up to fifty, to create what is known collectively as the “Event Horizon Telescope.” According to MIT’s Haystack Observatory, “A long standing goal in astrophysics is to directly observe the immediate environment of a putative black hole with angular resolution comparable to the event horizon. Realizing this goal would open a new window on the study of General Relativity in the strong field regime, accretion and outflow processes at the edge of a black hole, the existence of an event horizon, and fundamental black hole physics.”

As Stephen Hawking notes in his book, The Universe in a Nutshell (Bantam Press 2001), “the discovery of quasars in 1963 brought forth an outburst of theoretical work on black holes and observational attempts to detect them” (p. 113). “It would be an amazing thing,” says Daniel Marrone, of the University of Arizona’s Steward Observatory, “it’s never been done before, getting an image of a black hole.” Clearly, the results promised by the Event Horizon Telescope have been a long time coming for observational astronomers, with the prospects for significant advances in knowledge now tantalisingly close at hand. Quasar 3C 279 may not be the most distant, nor the largest expression of a cosmic monster out there (that title, for now, belongs to quasar ULAS J1120+0641), but its precious five billion year old photons have not made their long journey to earth’s observatories in vain. With each advancement in radio astronomy, with each successful international research collaboration, we sharpen our observational acuity in pursuit of the most elusive and merciless forces in the universe – black holes, and their dazzling creations, the quasars.

Daniel Zalec | nerditorial.com

On Curious Shoulders: Mars Rover Carries the Weight of the Future

JPL’s Mars Science Laboratory (MSL) mission has entered “approach phase,” according to Mission Manager Arthur Amador. Come arrival day, mission controllers will be biting their fingernails and wiping beads of nervous sweat from their brows, during what engineers describe as, “Seven Minutes of Terror.” In light of deep cuts to NASA’s Mars exploration budget, MSL’s success or failure may determine the course of planetary science for decades to come. The star of the show – Curiosity – a 900 kilogram rover, equipped with the most advanced scientific instruments ever sent to study the Martian surface – will burst into the planet’s thin atmosphere on August 5. As JPL engineer, Tom Rivellini explains, “we’ve got literally seven minutes to get from the top of the atmosphere to the surface of Mars, going from 13,000 miles an hour to zero, in perfect sequence, perfect choreography, perfect timing… If any one thing doesn’t work just right, it’s game over.”

A series of 76 pyrotechnic explosions, timed to the millisecond, must all work perfectly in order for Curiosity to experience a safe landing in Gale Crater. “If organics ever existed on Mars,” says JPL scientist, Matthew Golombek, “they could be preserved in the clay [of Gale Crater]. All the types of aqueous minerals we’ve detected on Mars to date can be found in this one location.” Examination of Martian meteorites suggests that the Red Planet contains the necessary building blocks for life, and has been undertaking organic chemistry for billions of years. Dr. Andrew Steele, Carnegie Institute Geophysical Laboratory scientist and member of MSL’s Sample Analysis at Mars team, led a recent study that confirmed the existence of “reduced carbon” on Mars.

Other meteorite analyses indicate that certain DNA building blocks can be created in space, lending weight to the theory that organic molecules on the early Earth may have been delivered by extraterrestrial objects. The potential implications for Mars and worlds beyond, are also significant. As noted in a 2011 paper, published in the Proceedings of the National Academy of Sciences, “Meteorites may have served as a molecular kit providing essential ingredients for the origin of life on Earth and possibly elsewhere.” In the words of Goddard Space Flight Center’s Dr. Michael Callahan, lead author of the study, “for the first time, we have three lines of evidence that together give us confidence these DNA building blocks actually were created in space.”

Such results add to the excitement surrounding Curiosity’s potential for groundbreaking discoveries. Its impressive mobile analytical capabilities may answer intriguing questions about the possibilities of life on Mars. Dr. Steele lightheartedly told BBC News in May that he would appreciate some rocks brought back from Mars to answer key questions on life, current or past. He may, however, have to wait a very long time for his Martian rocks to arrive. Even though the 2011 NRC Decadal Survey for Planetary Science specifies Martian sample return as a top science priority, budget cuts have left such missions in limbo.

Earlier in 2012, one would be hard pressed to find any semblance of jocularity from planetary scientists or astrobiologists, despite some attempts at levity. Indeed, the mood may not be much better now. In February, President Obama presented a Fiscal Year 2013 budget that slashed NASA’s planetary science budget by 20%, including a 39% reduction for the Mars Exploration Program. Scientists and commentators expressed shock and anger at the announcement. “Right now NASA’s Mars science exploration budget is being decimated,” said Dr. Neil deGrasse Tyson, Director of New York’s Hayden Planetarium, during a Senate testimony in March.

From the ashes of dismay and driven by necessity, came a directive from the NASA Administrator: To Reformulate the current Mars Exploration Program, and discontinue planned 2016/2018 joint missions with the European Space Agency (ESA). This reformulation spawned the Mars Program Planning Group (MPPG). Whilst MPPG’s directive is to develop options for a reformulated Mars Exploration Program, NASA makes clear that, “there should be no ambiguity that resources in support of MSL and its support elements take precedence over the activities of the MPPG… the operation of the orbiting missions-Mars Reconnaissance Orbiter and Odyssey-is considered a high priority as well.”

MPPG managed to harness widespread feelings of desperation, following the FY 2013 budget cut announcements. This was most clearly evidenced by the submission of approximately 400 concepts or abstracts – almost twice the expected number – for the Concepts and Approaches for Mars Exploration Workshop in Houston. Held from June 12 – 14, this workshop featured an international flavour of scientists, engineers and graduate students who discussed many bold ideas, from sample return missions to human exploration. A report of the meeting, Concepts and Approaches for Mars Exploration, provides a detailed summary of the broad range of concepts put forward.

How excited, though, should we be? For decades, there has never been a shortage of Mars mission concepts and certainly no lack of mission success stories. In fact, as noted by Mars Society Founder, Dr. Robert Zubrin, Mars exploration has been “brilliantly successful.” Lack of ideas has never threatened exploration programs; but lack of public will and short-sighted policymakers, have. Washington is the next stop for the concepts developed by the MPPG. Washington comes with no guarantees of support for bold mission proposals – manned or robotic – however high their stated scientific value. Perhaps the words of Planetary Society Co-Founder, Dr. Louis Friedman, best encapsulate this political reality: “Some days I’m very optimistic, I think we can do it [land humans on Mars] in ten, maybe fifteen years. Other days, I see all the political things that go into the space program, I look back on the thirty years we’ve been bogged down, and I get more negative about it and I say it’s going to be another three decades, four decades.”

One thing is certain: In the absence of adequate public will, a bruised and battered exploration program runs the risk of being sacrificed for political and economic expediency. Meanwhile, all eyes are on Curiosity – Will it land safely? What will it find? Could the car-sized rover spark a major shift in favour of planetary science, ultimately increasing the Mars Exploration Program budget? With enough public engagement, stemming from significant mission success and media interest, NASA’s Planetary Science Director, Dr. Jim Green, seems to think so. “I believe [Curiosity] will open up that new era of discovery that will compel this nation to invest more in planetary science,” Green told the 43rd Lunar and Planetary Science Conference on March 19.

To increase awareness, NASA is sponsoring initiatives such as the Mars Rover Curiosity Landing Educator Conference – aimed at engaging students and teachers in the excitement of the historic landing. Soon, JPL’s Mission Control Room will be oozing with tension, perhaps akin to that experienced by ESA’s Huygens Probe landing team on 14 January, 2005. NASA will be hoping for equally sweet celebrations on August 5, 2012.

Follow the MSL mission at: http://mars.jpl.nasa.gov/msl/

Daniel Zalec | nerditorial.com