Sunday, August 30, 2015

Geosonnet 31

Gyrations of a topsy-turvy world
Could spur migration of the cryosphere
No snowball Earth, just poles and tropics whorled
The data which support this are unclear.
Precambrian magnetic fields suggest
That tropics, poles exchanged with frightful speed.
Magnetic hysteresis is the test
Anorthosite and feldspar crystals need.
A shaky witness cross-examination
The steep magnetic field begins to fray
Faced with a single crystal refutation
The polar history has gone away.
   The Ediacaran poles didn't roam.
   Emerging life was blessed with stable home.

Geology 43 132

Other geosonnets: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Saturday, August 29, 2015

Hard rock men and soft rock girls

Readers with short attention spans who waste too much time on social media may have noticed that Brian Romans has been complaining over on twitter about the hardrock/ softrock divide. This being a blog, I will whinge in more depth below:

For those of you who grew up on a carbonaceous chondrite, there is a historical cultural divide between hardrock- the study of high temperature processes as recorded in crystalline rocks, and softrock- the study of low temperature processes which can be recorded in sediments.

I’m not sure where in the fossil record this division first appeared, but my experience of it goes back to teachers who were trained in the Apollo era. Back in the 60’s and 70’s, the moon race injected lots of cash into the study of (dead, high temperature) moon rocks and associated meteorites. A generation later, from the 90’s on, there has been an increasing push to understand climate, presumably in hope that we can learn something about it before it kills us all. One result of this change in focus is an unnecessary cultural divide, premised on lazy assumptions that in some cases are decades out of date.

For example, one of the strengths of the 20th century hardrock push was the elevation of petrology beyond a simple descriptive science to a thermodynamically constrained, math-based quantitative science. The calculations done with thermocalc or MELTS or any of the other equilibrium simulators are of course trivial compared to what goes into climate models or organic geochemistry or genetics, but some of the older, out-of-touch hardrock evangelists haven’t quite caught on to these developments yet. Similarly, researchers who have used the surge in climatological research funding to tackle new fields of research have sometimes been labeled as too soft to make it in hard rock, while in many cases they feel that their former fields of study have either had the interesting questions answered, or degenerated into untestable speculating.

In reality, the advancement in modern analytical, conceptual, and computational techniques means that the separation between hardrock and softrock is largely a psychological or historical one. As you carbonaceous chondrite dwellers surely appreciate, we have moved on from isotopic anomalies in presolar grains to organic cosmochemistry, the origin of chirality and life, and other burning questions that require understanding the interaction between low and high temperature processes in active planets. Even bread-and-butter questions like continental crust formation are increasingly having to deal with the effects of weathering (and how it changes as the atmosphere evolves), in order to explain increasingly detailed analyses. As a community, we should have realized way back when subduction was discovered that it is futile to separate aqueous and thermal processes on a planet whose thermal engine is driven by downgoing oceanic slabs.

Having met a lot of scientists over the years, the ones who use their skills to address a variety of questions across outdated subdisciplinary boundaries seem to be happier and more productive than those who choose to wave an archaic banner from a lost tribe of geoscience. From the 21st century, the hardrock / softrock divide seems as old fashioned as the Billy Joel song parodied below:

Softrock Girl

Softrock girl,
She’s been living in her softrock world.
I bet she’s never had a mantle guy
I bet her momma never told her why.

I’m gonna try for a softrock girl
She’s been living in her climate world
As long as anyone with magma can
and now she’s looking for a hard rock man

And when she knows what she wants from deep ti-i-ime
And when she wakes up and makes up her mi-i-ind
She’ll see I’m not so tough
Just because
I’m in love
With a softrock girl.

You know I’ve seen her in her soft rock world,
She’s getting tired of her plankton toys
and her presents from her soft rock boys
She’s got a choice.

Softrock girl
You know I can’t abide to study pearls
But maybe someday when my ship comes in
Drilling MOHO through the MORB so thin
and then I’ll win.

And when she’s walking on sand grains so fi-i-ine.
And when she’s drilling, she yearns for a mi-i-ine.
She’ll say I’m not so tough
Just because
I’m in love with a softrock girl
She’s been living in her climate world
As long as anyone with magma can
and now she’s looking for a hard rock man
That’s what I am
Softrock girl
She’s my softrock girl.
You know I’m in love with a
Softrock girl
My softrock girl.
You know I’m in love with a
Softrock girl
My softrock girl.


Thursday, August 06, 2015

A one-way ticket to an unsuspecting Kepler 452b?

There has been a bit in the science press about the newly discovered exoplanet, Kepler 452b. This related to the observation that it is in the “habitable zone” of a sun-like star.  The big news, as always, is that this planet is completely unlike anything in our solar system. If it is solid, it has three times the mass than every rocky body in our solar system combined. If it is not solid, then it is one of the sub-neptune planets common everywhere but around our star.  But there are two points in particular which have been ignored- or at least not appreciated, which I would like to expound on.

Firstly, we can see them, but they can’t see us.  There are two main techniques used for detecting planets around stars: Radial velocity, and transits.  The motion of the planet around the star pulls the star backwards and forwards, in proportion to their relative masses.

With the radial velocity method measures the very small Doppler shift in the light of the star created by this pull. However, in order to see this motion, the orbit of the planet around the star needs to be somewhat edge-on as seen from earth. If we are looking town down on the orbit, then the star doesn’t move towards or away from us; it just goes in a circle (or ellipse). And sideways motion in the sky is much harder to detect that motion towards of away from Earth.

With transit detection, the crossing of the planet across the face of the star (as seen from Earth) causes the light from the start to dim a little bit in a periodic fashion. This requires Earthly observers to be in the same plane as the orbit of the planet- For a Earth-like planet orbiting a sun-like star, the planet will only transit if the Earth is within a half degree of the planet’s orbital plane.  The Kepler mission is a transit mission; all the planets it detects are systems which are edge-on as seen from Earth.

For aliens trying to detect us using the transit method, they need to be viewing us from a star that lies in the ecliptic. Basically, if they want to see the Earth pass in front of the sun, to detect its transit, then from our point of view, the sun needs to cross in front of their star.

However, the Kepler primary mission* field of view is nowhere near the ecliptic. It is, fore the most part, more than 60 degrees from the ecliptic. This makes transit detection of the Earth in front of the sun impossible from any star systems in the original Kepler field of view. And due to the high angle, radial velocity measurements of the Earth’s pull on the sun will be less than half as effective as our radial velocity measurements of their planets.

So the Kepler mission isn’t just a telescope.  It is a spy satellite, peering down on a thousand planets circling hundreds of distance star, all of whom are blissfully unaware of our planet’s existence.  If there are aliens on Kepler 452b- or any other planet Kepler discovers, they aren’t waving at us, because assuming technological parity, they can’t possibly know that we are here.

Of course, we know that they are there.  And it might be that one day,. given a modest technological advancement, someone could sent a colony ship on a hundred thousand year mission to visit them.  However, the visit could easily overstay its welcome.

Kepler 452b is probably not an Earthlike planet. However, if it does have an Earthlike composition, then it is a gigantic hunk of rock and metal three times more massive than every rocky-metal planet in our solar system combined. Due to gravitational self-compression, this planet would have a mass six times that of Earth.  At 36 hellagrams, it is just under half the mass of Uranus. The surface gravity would be a crushing 2.3 times greater than on Earth.  No rocket we currently have could even leave the launch pad under suck crashing gravity.  And even if it did, the velocity required to achieve orbital velocity, 15.5 km/s, is almost twice what is required on Earth.

Although technology is sure to advance if we are to get the ability to launch colony ships, such a huge planet would trap any rocket conceivable with current technology.  Kepler 452b is, in essence, a gigantic Hotel California, from which no-one can ever leave.  As a result, any short-lived visitation attempt would inevitably become a permanent stay.

So don’t be too disappointed if the locals on Kepler 452b don’t wave back.  They are blissfully unaware that we are staring at them.  And if they did know, the fact that we would wear out our welcome upon visiting by a factor of infinity is unlikely to cheer them up.

 * The secondary mission, however, is observing on the ecliptic.


Friday, July 24, 2015

Geosonnet 30

The periodic dinner tables host
A smorgasbord of elemental food.
Without the nutrient that’s needed most,
The spread of life’s substantially subdued.
When goethite settled out of ancient seas
The phosphorus adhered to iron mush.
Experimental doping can appease
Silicic activists and calcite crush.
If photoferrotrophs consume the P
Archean ocean surface life can’t grow.
No photosynthesis, O can’t be free
‘till rivers from the first great mountains flow.
  Yet when a couple billion more years pass
  Not P, but iron grows the biomass.



 Other geosonnets: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

Tuesday, July 21, 2015

The biodiversity of topography



The central Australian desert is an extreme arid environment.  For 20 million years, the continent has been drying, its rivers turning to playas, its ground water salting up, its inland plains and plateaus slowly disappearing under waves of sand.  The plant kingdom has not abandoned the continent, though, and thousands of drought-tolerant plants inhabit the red centre of Australia.  This aridity is a fickle thing, however.  In this wide brown land we call home, a slight increase in water availability, or a bit of shade from the noonday sun can make a big difference to a tropical, moisture loving plant.

A stunning example of this is the cycad.  As this global distribution map shows, cycads are mostly found in tropical to sub-tropical forests, and in Australia, they hug the wetter coastal areas.  But there is one species not shown on this map.

In the central Australian Macdonnell ranges, Macrozamia macdonnelli is found in ravines, at the base of south facing cliffs, and in rare desert oases, where ground water and sun protection allow it to cling to life as the continent dried out.  1500 km from the ocean and about as far from its nearest living relative, these cycads are found through the MacDonnell and Hartz ranges of the Northern Territory, where steep ravines channel water and shade the plants which grow within. Like an outlawed bushranger on the run from the law, this plant and its pollinator sidekick have been hiding out from the sun in the secret mountain waterholes for millions of years.  


Monday, June 15, 2015

The Tim Hunt sleight of hand


The internet has been all atwitter about the blatantly sexist remarks made by Nobel laureate Tim Hunt earlier this week, at a women in scientist event in Korea.  These remarks have been roundly ridiculed, as is appropriate for such stupidity from such an influential scientist.  A few days later, after a half-assed apology, Professor Hunt resigned. 

This is unfortunate.  His resignation allows his university, not to mention the rest of academia, to “shoot the messenger” and use him as a scapegoat to ignore the structural problems that allow academia to shelter and perpetuate sexist behaviour in the first place. It is like treating cholera with doxycycline while ignoring the sewage.
Ideally, his remarks, which were basically an admission of sexual harassment and/or bullying, should have triggered the standard investigative processes at his universities.  If, in fact, he has been hiring in a gender-biased manner, or taking sexual advantage of starry-eyed underlings, or making his employees cry, then he should be dealt with using the appropriate channels.  By resigning in haste, it means that we have no way of gauging the efficacy of the university grievance policies, and it gives his victims no means of redress or compensation.
I have mentioned many times the depreofessionalization ofscience, and the attendant social problems that result.  However, the flip side of scientific research getting outsourced from the corporate world to academia is that it requires academia to get more professional.  This is especially true in those areas where commercial research is being done.  However, there has been a resistance from academia to adopt professional attitudes and work practices along with this work.  And this is one of the problems that allows sexist and racist hiring practices and work environments to persist in the ivory tower while private and public sector workplaces are trying to reduce them.
In all types of workplaces, people do fall in love.  Sometimes it works out, sometimes it doesn’t, and People hopefully learn to work out how to balance their personal and professional lives before their 72nd birthday.  But whether one believes the appropriate waiting time between leaving supervision and calling should be measured on the second hand or by the orbit of Mars, the admission of a senior researcher of committing damaging and unprofessional behaviour should not prompt knee-jerk resignation.  This just deflects attention from the institutional structures that either address or cover up these sorts of problems.  The issue is not Professor Hunt’s twinfamy; it is the inability of academic institutions to protect their junior personnel.

.



Wednesday, June 03, 2015

Geosonnet 29

The scent from Madagascar’s fine perfume
Enhances ice cream, fragrances the bath
Beyond this orchid spice a shadow looms:
A mass extinction’s lethal aftermath.
When sulfur, carbon oxidize in air
A surplus of ionic hydrogen
In rain burns plants, and leaches soil bare
Wrecked ecosystems cannot rise again.
Vanillin burns as microbes decompose
At high pH, vanillic acid’s made.
With only aldehyde, one could propose
An acid landscape, compounds undecayed.
   Pollution in the first Triassic rain
   Prevented life from sprouting up again.

Geology 43 159

 Other geosonnets: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

Saturday, May 09, 2015

Prime Minister's Business Advisory Chair loses his marbles.

On Friday, Maurice Newman, the chair of the Prime Minister’s Business Advisory Council, wrote a frothing opinion article in The Australian newspaper (paywalled). It reads more like a Evangelical Christian teenager’s blog than an op-ed by an adult with a job, but basically follows the delusional UN world order climate hoax script found on American survivalist websites and other reputable sources of scientific knowledge. Of course, it is not a crime to be a delusional conspiracy nut. And if tin foil hat sales are what we need to preserve our aluminum industry, I’m all for it. But having one of the PM’s chief economic advisors carry on this way is like having the head of the Canberra Deep Space network decrying the moon landings as a hoax. It is like the health minister saying that vaccines cause autism, or that fucking virgins cures AIDS. The only way it makes any since at all is if The Australian has transformed into a joke newspaper like The Chaser. Except that it isn't actually funny. If the Prime Minister expects his Business Advisory Council to be taken seriously, he should replace the chair with someone who actually has a grip on reality. Because it is difficult to have confidence in a person who publicly espouses lunacy.