Life in a rut: if microbes are commonplace, where does that leave intelligent aliens?

A few years ago I wrote about how Mars' seasonal methane fluctuations suggested - although far from confirmed - that microbial life might be present just under the Martin surface. Now another world in our solar system, the Saturnian moon Enceladus, has ignited discussion along similar lines.

The Cassini probe conducted flybys of Enceladus over a decade, revealing that Saturn's sixth largest moon was venting geyser-like jets of material, including water vapour, from its southern polar region. The material being emitted from these vents also included organic compounds and methane, hinting that this distant moon's watery oceans may also contain alien methane-producing microbes. Whereas Titan and Europa were originally deemed the moons most suitable for life, Enceladus's status has now been boosted to second only to Mars, with conditions not dissimilar to those in the oceans of the early Earth.

Of course, unknown geochemical processes cannot be ruled out, but nonetheless the quality of the evidence is such as to invite further exploration of Enceladus. There have been at least seven potential mission designs proposed by various bodies, including NASA and ESA, to gain more information about the moon and its geysers. Several of these include landers, while others would fly through a plume in order to examine the vented material for biosignatures. However, to date none have received official funding confirmation. As it stands the first probe to arrive might be billionaire Yuri Milner's privately-funded Breakthrough Enceladus, rather than one from a major organisation. However, don't hold your breath: the earliest any of these missions is likely to reach Enceladus is at some point in the 2030s.

What happens if future probes find evidence of microbial life on both Mars and Enceladus? Or even, whenever a method is found to reach it, in the ice-covered oceans of Jupiter's moon Europa? The first key fact will be whether they are genetically independent of Earth biota or if the panspermia hypothesis - the delivery of microbes via cometary and meteorite impact - has been proven. If that turns out not to be the case and multiple instances of life arose separately within a single solar system, this has some profoundly mixed implications for the search for extraterrestrial intelligence (SETI). After all, if simple life can arise and be sustained on three or even four very different worlds - including bodies far outside their solar system's 'Goldilocks zone' - then shouldn't this also imply a much higher chance of complex alien life evolving on exoplanets? 

Yet despite various SETI programmes over the past few decades, we have failed to pick up any signs of extraterrestrial intelligence - or at least from other technological civilisations prepared to communicate with radio waves, either in our galactic neighbourhood or with super high-powered transmitters further away. This doesn't mean they don't exist: advanced civilisations might use laser pulses at frequencies our SETI projects currently don't have the ability to detect. But nonetheless, it is a little disheartening that we've so far drawn a blank. If there is microbial life on either Mars or Enceladus - or even more so, on both worlds, never mind Europa - then a continued lack of success for SETI suggests the chances of intelligent life evolving are far lower than the probability of life itself arising.

In effect, this means that life we can only view via a microscope - and therefore somewhat lacking in cognitive ability - may turn out to be common, but intelligence a much rarer commodity. While it might be easy to say that life on both Enceladus and Mars wouldn't stand much of a chance of gaining complexity thanks to the unpleasant environmental conditions that have no doubt existed for much of their history, it's clear that Earth's biota has evolved via a complex series of unique events. In other words, the tortuous pathways of history have influenced the evolution of life on Earth.

Whereas the discovery of so many exoplanets in the past decade might imply an optimistic result for the Drake equation, the following factors, being largely unpredictable, infrequent or unique occurrences, might suggest that the evolution of complex (and especially sapiens-level intelligent) life is highly improbable:

• The Earth orbits inside the solar system's Goldilocks zone (bear in mind that some of the planets have moved from the region of space they were created in) and so water was able to exist in liquid form after the atmospheric pressure became high enough.
• The size and composition of the planet is such that radioactivity keeps the core molten and so generates a magnetic field to block most solar and cosmic radiation.
• It is hypothesised that the Earth was hit by another body, nicknamed Theia, that both tilted the planet's axis and caused the formation of the Moon rather than having a catastrophic effect such as tearing our world apart, knocking it on its side (like Uranus) or removing its outer crust (like Mercury).
• The Moon is comparatively large and close to the Earth and as such their combined gravitational fields help to keep Earth in a very stable, only slightly eccentric orbit. This is turn has helped to maintain a relatively life-friendly environment over the aeons. 
• The Earth's axial tilt causes seasons and as such generates a simultaneous variety of climates at different latitudes, providing impetus for natural selection.
• The Great Unconformity and hypothesised near-global glaciation (AKA Snowball Earth) that might have caused it suggests this dramatic period of climate change led to the development of the earliest multi-cellular life around 580 million years ago.
• Mass extinctions caused rapid changes in global biota without destroying all life. Without the Chicxulub impactor for example, it is unlikely mammals would have radiated due to the dominance of reptiles on the land.
• Ice ages over the past few million years have caused rapid climate fluctuations that may have contributed to hominin evolution as East African forests gave way to grasslands.

The evolutionary biologist Stephen Jay Gould often discussed 'contingency', claiming that innumerable historical events had led to the evolution of Homo sapiens and therefore that if history could be re-run, most possible paths would not lead to a self-aware ape. Therefore, despite the 4,800 or so exoplanets discovered so far, some within their system's Goldilocks zone, what is the likelihood such a similar concatenation of improbable events would occur of any of them? 

Most people are understandably not interested in talking to microbes. For a start, they are unlikely to gain a meaningful reply. Yet paradoxically, the more worlds that microbial life is confirmed on, when combined with the distinct failure of our SETI research to date, the easier it is to be pessimistic; while life might be widespread in the universe, organisms large enough to view without a microscope, let alone communicate with across the vast reaches of interstellar space, may be exceedingly rare indeed. The origins of life might be a far easier occurrence than we used to think, but the evolution of technological species far less so. Having said that, we are lucky to live in this time: perhaps research projects in both fields will resolve this fundamental issue within the next half century. Now wouldn't that be amazing?

Mushrooms to Mars: how fungi research could help long-duration space travel

I've often noted that fungi are the forgotten heroes of the ecosystem, beavering away largely out of sight and therefore out of mind. Whether it's the ability to break down plastic waste or their use as meat substitutes and pharmaceuticals, this uncharismatic but vital life form no doubt hold many more surprises in store for future research to discover. It's estimated that less than ten percent of all fungi species have so far been scientifically described; it's small wonder then that a recent study suggests an entirely new use for several types of these under-researched organisms.

Investigation of the Chernobyl nuclear power station in 1991 found that Cladosporium sphaerospermum, a fungus first described in the late nineteenth century, was thriving in the reactor cooling tanks. In other words, despite the high levels of radiation, the species was able to not only repair its cells but maintain a good rate of growth in this extreme environment. This led to research onboard the International Space Station at the end of 2018, when samples of the fungus were exposed to a month of cosmic radiation. The results were promising: a two millimetre thick layer of the fungus absorbed nearly two percent of the radiation compared to a fungus-free control.

This then suggests that long-duration crewed space missions, including to Mars, might be able to take advantage of this material to create a self-repairing radiation shield, both for spacecraft and within the walls of surface habitats. A twenty-one centimetre thick layer was deemed effective against cosmic rays, although this could potentially be reduced to just nine centimetres if the fungal mycelia were mixed with similar amounts of Martian soil. In addition, there is even the possibility of extracting the fungus' radiation-proof melanin pigment for use in items that require much thinner layers, such as spacesuit fabric.

If this sounds too good to be true, there are still plenty of technological hurdles to be overcome. Science fiction has frequently described the incorporation of biological elements into man-made technology, but it's early days as far as practical astronautics is concerned. After all, there is the potential for unique dangers, such as synthetic biology growing unstoppably (akin to scenarios of runaway nanobot replication). However, NASA's Innovative Advanced Concepts program (NIAC) shows that they are taking the idea of fungi-based shielding seriously, the current research considering how to take dormant fungal spores to Mars and then add water to grow what can only be described as myco-architecture elements - even interior fittings and furniture. In addition to the radiation shielding, using organic material also has the advantage of not having to haul everything with you across such vast distances.

Even more ideas are being suggested for the use of similarly hardy species of fungi on a Mars base, from bioluminescent lighting to water filtration. Of course, this doesn't take into account any existing Martian biology: the seasonal methane fluctuations that have been reported are thought by some to be too large to have a geochemical cause; this suggests that somewhere in the sink holes or canyon walls of Mars there are colonies of methane-producing microbes, cosily shielded from the worst of the ultraviolet. If this proves to be the case, you would hope that any fungi taken to the red planet would be genetically modified to guarantee that it couldn't survive outside of the explorer's habitats and so damage Martian biota. Humanity's track record when it comes to preserving the ecosystems of previously isolated environments is obviously not something we can be proud of!

What fungi can do alone, they also do in symbiosis with algae, i.e. as lichens. Various experiments, including the LIchens and Fungi Experiment (LIFE) on the International Space Station (incidentally, doesn't NASA love its project acronyms?) have tested extremophile lichens such as Xanthoria elegans and Rhizocarpon geographicum in simulated Martian environments for up to eighteen months. The researchers found that the organisms could remain active as long as they were partially protected, as if they were growing in sink holes beneath the Martian surface. Of course, this success also enhances the possibility of similar lifeforms already existing on the red planet, where it would have had eons in which to adapt to the gradually degraded conditions that succeeded Mars' early, clement, phase.

The CRISPR-Cas9 system and its successors may well develop synthetic fungi and lichens that can be used both on and especially off the Earth, but we shouldn't forget that Mother Nature got there first. Spacecraft shielding and myco-architecture based on natural or genetically modified organisms may prove to be an extremely efficient way to safeguard explorers beyond our world: the days of transporting metal, plastic and ceramic objects into space may be numbered; the era of the interplanetary mushroom may be on the horizon. Now there's a phrase you don't hear every day!

Wildfires and woeful thinking: why have Australians ignored global warming?

In a curious example of serendipity, I was thinking about a quote from the end of Carl Sagan's novel Contact ("For small creatures such as we the vastness is bearable only through love") just a few minutes before discovering his daughter Sasha Sagan's book For Small Creatures Such as We. Okay, so I didn't buy the book - due to the usual post-Christmas funds shortage - and cannot provide a review, but this indication of our place in the scale of creation is something that resonates deep within me.

I've often discussed how biased we are due to our physical size, especially when compared to other species we share the planet with. However, I've never really considered that other fundamental dimension, time. Another Carl Sagan quote echoes many a poet's rumination on our comparatively brief lifespan: "We are like butterflies who flutter for a day and think it is forever."

There's more to this than just fairly familiar poetic conceit. Earlier this month I was given a brief taste of what it might be like to live on Mars, thanks to high-altitude dust and ash transported across the Tasman Sea from the Australian bush fires. By three o'clock in the afternoon a New Zealand summer's day was turned into an eerie orange twilight, with birds and nocturnal insects starting their evening routine some five hours early. There was even a faint powdery, acrid taste in the air, adding to the sense of other-worldliness.

Apart from the obvious fact that this an example of how climate change in one nation can affect another, there is a more disturbing element to all this. Why is it that despite the reports and general consensus of the global climate science community Australians have shown a woeful lack of interest, or indeed, negativity, towards climate change?

Could it be that our society is now centred upon such short increments of time (competing businesses trying to out-do each other, which comes down to working at the ever-increasing speed our technology dictates) that we have replaced analysis with unthinking acceptance of the simplest and most aggressive opinions? Research shows that compared to even twenty years' ago, children read far less non-school literature and rely on the almost useless 'celebrity' shouters of social media for much of their information; there's not much chance of learning about informed, considered arguments via these sources!

After all, it's difficult for most of us to remember exact details of the weather a year ago, but understanding climate change relies on acceptance of directional trends over at least decades. How much easier is it to accept the opinions of those who preserve the status quo and claim we can maintain our current lifestyle with impunity? When combined with the Western capitalist notion of continuous growth and self-regulation, we see a not-so-subtle indoctrination that describes action to prevent climate change as disruptive to the fundamental aspects of the society that has arisen since the Industrial Revolution.

There is an old French saying that we get the government we deserve, which in Australia's case, implies a widespread desire to ignore or even deny global warming. Yet the irony is that of all developed nations, Australia has been at the receiving end of some of its worst effects, thanks to an average increase in daily temperature of several degrees over past century. It takes little cognition to understand how this can lead to the drier conditions that have caused the horrific bush fires; even though some have been deliberately started, their scale has been exacerbated by the change of climate. So what until now has prevented Australians from tying the cause to the effects?

It's not as if there isn't plenty of real-world evidence. However, with computer technology able to generate 'deep fakes', which implies a level of sophistication that only experts can detect, is the public becoming mistrustful of the multitude of videos and photographs of melting polar caps and shrinking glaciers? When combined with the decreased trust in authority figures, scientists and their technical graphs and diagrams don't stand much of a chance of acceptance without a fair amount of suspicion. As mentioned, it's difficult to understand the subtleties inherent in much of science when you are running at breakneck speed just to stand still; slogans and comforting platitudes are much more acceptable - unless of course people become caught up in the outcome themselves.

However, this doesn't explain why it is the key phrases such as 'climate change' and 'global warming' generate such negative sentiment, even from those Australian farmers who admit to hotter, drier conditions than those experienced by their parents' and grandparents' generations. Somehow, these sober terms have become tainted as political slogans rather than scientifically-derived representations of reality. That this negativity has been achieved by deniers seems incredible, when you consider that not only does it run counter to the vast majority of report data but that it comes from many with vested interests in maintaining current industrial practices and levels of fossil fuel usage.

Could it simply be a question of semantics, with much-used labels deemed unacceptable at the same time as the causes of directly-experienced effects accepted as valid? If so, it would suggest that our contemporary technological society differs little from the mindset of pre-industrial civilisation, in which leaders were believed to have at very least a divine right to rule, or even a divine bloodline. In which case, is it appalling to suggest that the terrible bush fires have occurred not a minute too soon?

If it is only by becoming victims at the tip of the impending (melted) iceberg that global warming is deemed genuine, then so be it. When scientists are mistrusted and activists labelled as everything from misguided to corrupt and scheming manipulators, this might only leaves a taste of what lies ahead to convince a majority who would otherwise rather keep doing as they always have done and trust politicians to do the thinking for them. I can think of nothing more apt to end on than another Carl Sagan quote: "For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring."

Life on Mars? How accumulated evidence slowly leads to scientific advances

Although the history of science is often presented as a series of eureka moments, with a single scientist's brainstorm paving the way for a paradigm-shifting theory, the truth is usually rather less dramatic. A good example of the latter is the formulation of plate tectonics, with the meteorologist Alfred Wegener's continental drift being rejected by the geological orthodoxy for over thirty years. It was only with the accumulation of data from late 1950's onward that the mobility of Earth's crust slowly gained acceptance, thanks to the multiple strands of new evidence that supported it.

One topic that looks likely to increase in popularity amongst both public and biologists is the search for life on Mars. Last month's announcement of a lake deep beneath the southern polar ice cap is the latest piece of observational data that Mars might still have environments suitable for microbial life. This is just the latest in an increasing body of evidence that conditions may be still be capable of supporting life, long after the planet's biota-friendly heyday. However, the data hasn't always been so positive, having fluctuated in both directions over the past century or so. So what is the correspondence between positive results and the levels of research for life on Mars?

The planet's polar ice caps were first discovered in the late Seventeenth Century, which combined with the Earth-like duration of the Martian day implied the planet might be fairly similar to our own. This was followed a century later by observation of what appeared to be seasonal changes to surface features, leading to the understandable conclusion of Mars as a temperate, hospitable world covered with vegetation. Then another century on, an early use of spectroscopy erroneously described abundant water on Mars; although the mistake was later corrected, the near contemporary reporting of non-existent Martian canals led to soaring public interest and intense speculation. The French astronomer Camille Flammarion helped popularise Mars as a potentially inhabited world, paving the way for H.G. Wells' War of the Worlds and Edgar Rice Burroughs' John Carter series.

As astronomical technology improved and the planet's true environment became known (low temperatures, thin atmosphere and no canals), Mars' popularity waned. By the time of Mariner 4's 1965 fly-by, the arid, cratered and radiation-smothered surface it revealed only served to reinforce the notion of a lifeless desert; the geologically inactive world was long past its prime and any life still existing there probably wouldn't be visible without a microscope.

Despite this disappointing turnabout, NASA somehow managed to gain the funding to incorporate four biological experiments on the two Viking landers that arrived on Mars in 1976. Three of the experiments gave negative results while the fourth was inconclusive, most researchers hypothesising a geochemical rather than biological explanation for the outcome. After a decade and a half of continuous missions to Mars, this lack of positive results - accompanied by experimental cost overruns - probably contributed to a sixteen-year hiatus (excluding two Soviet attempts at missions to the Martian moons). Clearly, Mars' geology by itself was not enough to excite the interplanetary probe funding czars.

In the meantime, it was some distinctly Earth-bound research that reignited interested in Mars as a plausible source of life. The 1996 report that Martian meteorite ALH84001 contained features resembling fossilised (if extremely small) bacteria gained worldwide attention, even though the eventual conclusion repudiated this. Analysis of three other meteorites originating from Mars showed that complex organic chemistry, lava flows and moving water were common features of the planet's past, although they offered no more than tantalising hints that microbial life may have flourished, possibly billions of years ago.

Back on Mars, NASA's 1997 Pathfinder lander delivered the Sojourner rover. Although it appeared to be little more than a very expensive toy, managing a total distance in its operational lifetime of just one hundred metres, the proof of concept led to much larger and more sophisticated vehicles culminating in today’s Curiosity rover.

The plethora of Mars missions over the past two decades has delivered immense amounts of data, including that the planet used to have near-ideal conditions for microbial life - and still has a few types of environment that may be able to support miniscule extremophiles.

Together with research undertaken in Earth-bound simulators, the numerous Mars projects of the Twenty-first Century have to date swung the pendulum back in favour of a Martian biota. Here are a few prominent examples:

• 2003 - atmospheric methane is discovered (the lack of active geology implying a biological rather than geochemical origin)
• 2005 - atmospheric formaldehyde is detected (it could be a by-product of methane oxidation)
• 2007 - silica-rich rocks, similar to hot springs, are found
• 2010 - giant sinkholes are found (suitable as radiation-proof habitats)
• 2011 - flowing brines and gypsum deposits discovered
• 2012 - lichen survived for a month in the Mars Simulation Laboratory
• 2013 - proof of ancient freshwater lakes and complex organic molecules, along with a long-lost magnetic field
• 2014 - large-scale seasonal variation in methane, greater than usual if of geochemical origin
• 2015 - Earth-based research successfully incubates methane-producing bacteria under Mars-like conditions
• 2018 - a 20 kilometre across brine lake is found under the southern polar ice sheet

Although these facts accumulate into an impressive package in favour of Martian microbes, they should probably be treated as independent points, not as one combined argument. For as well as finding factors supporting microbial life, other research has produced opposing ones. For example, last year NASA found that a solar storm had temporarily doubled surface radiation levels, meaning that even dormant microbes would have to live over seven metres down in order to survive. We should also bear in mind that for some of each orbit, Mars veers outside our solar system's Goldilocks Zone and as such any native life would have its work cut out for it at aphelion.

A fleet of orbiters, landers, rovers and even a robotic helicopter are planned for further exploration in the next decade, so clearly the search for life on Mars is still deemed a worthwhile effort. Indeed, five more missions are scheduled for the next three years alone. Whether any will provide definitive proof is the big question, but conversely, how much of the surface - and sub-surface - would need to be thoroughly searched before concluding that Mars has either never had microscopic life or that it has long since become extinct?

What is apparent from all this is that the quantity of Mars-based missions has fluctuated according to confidence in the hypothesis. In other words, the more that data supports the existence of suitable habitats for microbes, the greater the amount of research to find them. In a world of limited resources, even such profoundly interesting questions as extra-terrestrial life appear to gain funding based on the probability of near-future success. If the next generation of missions fails to find traces of even extinct life, my bet would be a rapid and severe curtailing of probes to the red planet.

There is a caricature of the stages that scientific hypotheses go through, which can ironically best be described using religious terminology: they start as heresy; proceed to acceptance; and are then carved into stone as orthodoxy. Of course, unlike with religions, the vast majority of practitioners accept the new working theory once the data has passed a certain probability threshold, even if it totally negates an earlier one. During the first stage - and as the evidence starts to be favourable - more researchers may join the bandwagon, hoping to be the first to achieve success.

In this particular case, the expense and sophistication of the technology prohibits entries from all except a few key players such as NASA and ESA. It might seem obvious that in expensive, high-tech fields, there has to be a correlation between hypothesis-supporting facts and the amount of research. But this suggests a stumbling block for out-of-the-box thinking, as revolutionary hypotheses fail to gain funding without at least some supporting evidence.

Therefore does the cutting-edge, at least in areas that require expensive experimental confirmation, start life as a chicken-and-egg situation? Until data providentially appears, is it often the case that the powers-that-be have little enticement for funding left-field projects? That certainly seems to have been true for meteorologist Alfred Wegener and his continental drift hypothesis, since it took several research streams to codify plate tectonics as the revolutionary solution. 

Back to Martian microbes. Having now read in greater depth about seasonal methane, it appears that the periodicity could be due to temperature-related atmospheric changes. This only leaves the scale of variation as support for a biological rather than geochemical origin. Having said that, the joint ESA/Roscosmos ExoMars Trace Gas Orbiter may find a definitive answer as to its source in the next year or so, although even a negative result is unlikely to close the matter for some time to come. Surely this has got to be one of the great what-ifs of our time? Happy hunting, Mars mission teams!

Navigating creation: A Cosmic Perspective with Neil deGrasse Tyson

I recently attended an interesting event at an Auckland venue usually reserved for pop music concerts. An audience in the thousands came to Neil deGrasse Tyson: A Cosmic Perspective, featuring the presenter of Cosmos: A Spacetime Odyssey and radio/tv show StarTalk. The 'Sexiest Astrophysicist Alive' presented his brand of science communication to an enormous congregation (forgive the use of the word) of science fans aged from as young as five years old. So was the evening a success? My fellow science buffs certainly seemed to have enjoyed it, so I decided it would be worthwhile to analyse the good doctor's method of large-scale sci-comm.

The evening was split into three sections, the first being the shortest, a primer as to our location in both physical and psychological space-time. After explaining the scale of the universe via a painless explanation of exponents, Dr Tyson used the homespun example of how stacking the 'billions' (which of course he declared to be Carl Sagan's favourite word) of Big Macs so far sold could be stacked many times around the Earth's circumference and even then extend onwards to the Moon and back. Although using such a familiar object in such unusual terrain is a powerful way of taking people outside their comfort territory, there was nothing new about this particular insight, since Dr Tyson has been using it since at least 2009; I assume it was a case of sticking to a tried-and-trusted method, especially when the rest of the evening was (presumably) unscripted.

Having already belittled our location in the universe, the remainder of the first segment appraised our species' smug sense of superiority, questioning whether extra-terrestrials would have any interest in us any more than we show to most of the biota here on Earth. This was a clear attempt to ask the audience to question the assumptions that science fiction, particularly of the Hollywood variety, has been popularising since the dawn of the Space Age. After all, would another civilisation consider us worthy of communicating with, considering how much of our broadcasting displays obvious acts of aggression? In this respect, Neil deGrasse Tyson differs markedly from Carl Sagan, who argued that curiosity would likely be a mutual connection with alien civilisations, despite their vastly superior technology. Perhaps this difference of attitude isn't surprising, considering Sagan's optimism has been negated by both general circumstance and the failure of SETI in the intervening decades.

Dr Tyson also had a few gibes at the worrying trend of over-reliance on high technology in place of basic cognitive skills, describing how after once working out some fairly elementary arithmetic he was asked which mobile app he had used to gain the result! This was to become a central theme of the evening, repeated several times in different guises: that rather than just learning scientific facts, non-scientists can benefit from practising critical thinking in non-STEM situations in everyday life.

Far from concentrating solely on astrophysical matters, Dr Tyson also followed up on topics he had raised in Cosmos: A Spacetime Odyssey regarding environmental issues here on Earth. He used Apollo 8's famous 'Earthrise' photograph (taken on Christmas Eve 1968) as an example of how NASA's lunar landing programme inspired a cosmic perspective, adding that organisation such as the National Oceanic and Atmospheric Administration and the Environmental Protection Agency were founded during the programme. His thesis was clear: what began with political and strategic causes had fundamental benefits across sectors unrelated to space exploration; or as he put it "We're thinking we're exploring the moon and we discovered the Earth for the first time."

The second and main part of the event was Tyson's discussion with New Zealand-based nanotechnologist and science educator Michelle Dickinson, A.K.A. Nanogirl. I can only assume that there aren't any New Zealand astronomers or astrophysicists as media-savvy as Dr Dickinson, or possibly it's a case of celebrity first and detailed knowledge second, with a scientifically-minded interviewer deemed to have an appropriate enough mindset even if not an expert in the same specialisation.

The discussion/interview was enlightening, especially for someone like myself who knows Neil deGrasse Tyson as a presenter but very little about him as a person. Dr Tyson reminisced how in 1989 he accidentally become a media expert solely on the basis of being an astrophysicist and without reference to him as an Afro-American, counter to the prevailing culture that only featured Afro-Americans to gain their point of view.

Dr Tyson revealed himself to be both a dreamer and a realist, the two facets achieving a focal point with his passion for a crewed mission to Mars. He has often spoken of this desire to increase NASA's (comparatively small) budget so as reinvigorate the United States via taking humans out from the humdrum comfort zone of low earth orbit. However, his understanding of how dangerous such a mission would be led him to state he would only go to Mars once the pioneering phase was over!

His zeal for his home country was obvious - particularly the missed opportunities and the grass roots rejection of scientific expertise prevalent in the United States - and it would be easy to see his passionate pleas for the world to embrace Apollo-scale STEM projects as naïve and out-of-touch. Yet there is something to be said for such epic schemes; if the USA is to rise out of its present lassitude, then the numerous if unpredictable long-term benefits of, for example, a Mars mission is a potential call-to-arms.

The final part of the evening was devoted to audience questions. As I was aware of most of the STEM and sci-comm components previously discussed this was for me perhaps the most illuminating section of the event. The first question was about quantum mechanics, and so not unnaturally Dr Tyson stated that he wasn't qualified to answer it. Wouldn't it be great if the scientific approach to expertise could be carried across to other areas where people claim expert knowledge that they don't have?

I discussed the negative effects that the cult of celebrity could have on the public attitude towards science back in 2009 so it was extremely interesting to hear questions from several millennials who had grown up with Star Talk and claimed Neil deGrasse Tyson as their idol. Despite having watched the programmes and presumably having read some popular science books, they fell into some common traps, from over-reliance on celebrities as arbiters of truth to assuming that most scientific theories rather than just the cutting edge would be overturned by new discoveries within their own lifetimes.

Dr Tyson went to some lengths to correct this latter notion, describing how Newton's law of universal gravitation for example has become a subset of Einstein's General Theory of Relativity. Again, this reiterated that science isn't just a body of facts but a series of approaches to understanding nature. The Q&A session also showed that authority figures can have a rather obvious dampening effect on people's initiative to attempt critical analysis for themselves. This suggests a no-win situation: either the public obediently believe everything experts tell them (which leads to such horrors as the MMR vaccine scandal) or they fail to believe anything from STEM professionals, leaving the way open for pseudoscience and other nonsense. Dr Tyson confirmed he wants to teach the public to think critically, reducing gullibility and thus exploitation by snake oil merchants. To this end he follows in the tradition of James 'The Amazing' Randi and Carl Sagan, which is no bad thing in itself.

In addition, by interviewing media celebrities on StarTalk Dr Tyson stated how he can reach a far wider audience than just dedicated science fans. For this alone Neil deGrasse Tyson is a worthy successor to the much-missed Sagan. Let's hope some of those happy fans will be inspired to not just dream, but actively promote the cosmic perspective our species sorely needs if we are to climb out of our current doldrums.