Category Archives: Planetary geology

Subcutaneous oceans on distant moons; Enceladus and Europa

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Our blue Earth, rising above the lunar horizon, is an abiding image of our watery state that must evoke an emotional response in any sensible person. Cloud-swirled, Van Gogh-like. Such a blue – there’s nothing like it, at least in our own solar system.  A visitor to Mars three billion years ago might have also seen a red planet daubed blue, but all those expanses of water have since vanished, replaced by seas of sand.

Earth’s oceans are unique in our corner of the universe. Except for a thin carapace of ice at the poles, they are in a liquid state, and are in direct contact with the atmosphere to the extent that feed-back processes control weather patterns and climates.  Sufficient gravitational pull plus the damping effect of our atmosphere, prevents H2O from being stripped from our planet by solar radiation (again, unlike Mars). Our oceans exist because of this finely tuned balancing act. Continue reading

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Near Earth Objects; the database designed to save humanity

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The media love natural disasters, even those that don’t exist. Last week (early October, 2017), dramatic footage of a (simulated) super-volcano eruption beneath Auckland city was aired by several international media outlets, with headlines announcing the city’s calamitous destruction. But there is no super-volcano beneath Auckland. The excitement was short-lived.  While Auckland smouldered (as if that wasn’t enough), it was announced that New Zealand’s North Island could experience a subduction zone earthquake that, in its aftermath, would leave 1000s dead. An interesting backdrop to New Zealand’s recent election. Having scared the local population to death, our purveyors of science moved on to the next concern; other “what ifs…”.

Asteroid impacts are no longer de rigueur; perhaps it’s the turn of super-volcanoes’, or because NASA and the European Space Agency (ESA) have stated, with some confidence, that no large impacts are expected within the next 100 years. And whereas the media may find this Continue reading

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The origin of life: Panspermia, meteorites, and a bit of luck

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In the opening scenes of Stanley Kubrick’s 2001 Space Odyssey (1968), Neanderthal-like folk are scrounging for food, squabbling with a neighbouring tribe who are intent on competing for the meagre lickings (a reactionary condition that would not bode well for future humanity). One of them picks up a large bone.   There’s instant recognition, seemingly influenced by a black obelisk that appears mysteriously, that it can be used for something else. His neighbour lies in a crumpled heap. In what has become an enduring Sci-fi image, he triumphantly hurls his weapon into the air, whereupon Kubrick transforms it into an orbiting space station. Continue reading

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The intriguing paradox of global warming piggybacking on global cooling

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Flood, fire, drought … We have, by luck and muddled management, thwarted pestilence, but it seems that changing weather patterns everywhere are leading us on a merry dance.  Our climate is giving us a bumpy ride; anyone living in the Caribbean and southeast US, or Bangladesh, will attest to this, given the havoc that hurricanes and tropical cyclones have wrought over the past few months (northern hemisphere summer, 2017).  The skinny, outer layers of our world (air and oceans) seem to be getting warmer. No doubt there are consequences?

It may seem paradoxical, but global warming is taking place against a backdrop of global cooling. Forcing of global climates is governed by internal (within our own skinny sphere) and external agents; the latter by solar output and earth’s changing orbit. There is now, good Continue reading

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Io; Zeus’s fancy and Jupiter’s moon

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Zeus, the head-honcho of assorted Greek gods, heroes, nymphs, and mortals, was chiefly the God of the Sky, or Heavens. One of his minor portfolios was the upholding of Honour, but, as mythology relates, he didn’t put much energy into that particular task; he was a philanderer, much to the annoyance of his own wife, Hera (I guess his energies were directed elsewhere).  One such misdirection was Io, a mortal woman, who had the misfortune to be turned into a heifer by Zeus, to hide the infidelity from Hera. Io’s memory now survives as planetary body; one of the Galilean moons of Jupiter is named after her (to be named a moon of the Roman God Jupiter, seems like a historical slap in the face to the Greek deity). Continue reading

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Life on Mars; what are we searching for?

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I believe alien life is quite common in the universe, although intelligent life is less so. Some say it has yet to appear on planet Earth. Stephen Hawking

I can only imagine H.G. Wells bitter disappointment if he were to learn that Martians were little more than primitive microbes.  All that hype and scare-mongering for nothing. Because that, it seems, is all we are ever likely to find on Mars. They may be intelligent microbes, but microbes nonetheless.

Present conditions on Mars are not conducive to thriving populations of anything living – at least in any life form we are familiar with. Incident UV and other solar radiation, low atmospheric pressure, an atmosphere almost devoid of oxygen, and the presence in soils of oxidizing molecular compounds such as perchlorates and hydrogen peroxide (think bleached hair), all contribute to rather inclement living conditions. It is possible that some life forms have survived these ravages, in sheltered enclaves or buried beneath the scorched earth, but it is more likely that, if life did exist on Mars, we will find the evidence written into ancient sedimentary rocks, or perhaps as chemical signatures.  It is these attributes that current exploration programs, both landed rover expeditions and orbiting satellites, tend to focus on. Continue reading

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Which satellite is that? What does it measure?

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Space may well be the final frontier (there are one or two on earth that still require some work), but the space around our own planet is decidedly crowded. Folk at NASA’s Goddard Space Center (Maryland) estimate about 2300 satellites now orbit Earth; vehicles in various states of repair, use or disuse, of which a little more than 1400 are operational Continue reading

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