Thursday, November 20, 2014

The wrong kind of Bang

In science education and popularization, there is a delicate balance that must be struck between overcomplicating and oversimplifying. Insufficient simplification can result in overly obtuse deviation into secondary details, which confuse and distract the readers and derail the flow of the prose.  Excess simplification can be wrong.  And this is where the Medium article by Ethan Siegel of “Starts with a Bang” fame has ended up. 

Dr. Siegel argues that the recent Philae comet lander would have more successful if it had been powered with a 238Pu RTG device instead of solar panels.  However, his simplified argument ignores the reality of 238Pu fuel production, the definition of “we”, and the nature of comets.

238Pu is a byproduct of the nuclear arms race between the USA and the USSR. It is created by neutron activation of 237Np, which in turn is a byproduct of 239Pu production for nuclear weapons. With the nuclear arms deals of the 1980’s the superpowers stopped building nuclear weapons by the tens of thousands, and the cheap source of 237Np disappeared.  The USA stopped 238Pu production in 1988, all subsequent material has come from Russia, which has almost depleted its stockpiles.

This brings us to the definition of “we”.  As the battleground over which the USA and the USSR fought, Europe never developed its own mass nuclear warhead production facilities; the UK and French arms supplies are only a tiny fraction of the size of the 20th century superpowers.  As a result, Europe has never had its own large scale 238Pu production facilities. 

Philae was a European mission, not a USA or Russian one, so the ESA (European Space Agency) did not have access to 238Pu needed for RTG production.  NASA (USA) and the ESA (Europe) are separate space exploration entities, a point that was very unclear from this article’s frequent discussion of NASA and Philae.

Finally, RTG’s are hot, and comets are cold. The Philae lander was a very risky mission- there was a significant chance that it would not succeed at all, and in the end the lander ended up bounding off an unexpectedly hard surface several times before ending up on its side in a crater.

Comets, by definition, evaporate at low temperatures- this one is jetting out gasses despite being way out beyond the asteroid belt. So landing a heat-producing source on it, especially on a lander that ended up tipping over, would end up in a situation where the lander could drastically alter the local environment of the comet through thermal contact.  The whole point of the mission is to sample a comet in as pristine condition as possible, so potentially cooking the comet due to a landing mishap is not really a sensible design choice.

Dr. Siegel is correct that 238Pu is crucial for missions that operate beyond the orbit of Jupiter.  But the fuel used on previous missions was subsidized by the nuclear arms race.  It, and all the wondrous outer solar system exploration it allows, was an unintended byproduct of Mutually Assured Destruction, and the tens of thousands of nuclear weapons that policy produced.  Since the arms race ended, production of this isotope for the sole purpose of planetary exploration has been deemed too expensive to pursue by all the world’s governments.  Until we collectively decide to blow ourselves up again, this barrier to outer solar system exploration will continue.


Wednesday, November 19, 2014

Geosonnet 19

The Permian extinction was severe,
though only callous geos call it "great."
Sulfur and carbon choked the atmosphere
Siberian eruption exhalate.
A lava-coal explosion, it’s surmised
Spread fly ash all around the sickly Earth,
But if this ash is made by wildfire,
The evidence for coal fly ash is dearth.
A sulfate drought could set the world aflame,
The brimstone vapors choking off the rain.
The lava’s murder weapon’s not the same,
But "Lip" can improvise to kill again.
   If carbon, sulfur cycles stop their flow
   The ecosystem has nowhere to go.

Sunday, November 16, 2014

This is how I like to eat slugs

Slugs are full of protein, but it is dangerous to eat them raw.  So I process them by using a pack of domesticated dinosaurs to turn the slimy molluscs into slimy egg yolk.  This has the added bonus of keeping them off of the vegetables. Everybody wins.

Wednesday, November 12, 2014

Geosonnet 18

The Vikings lived in Greenland 'till in cooled.
Ten thousand years before, as glac'ers thawed,
Melt water in the North Atlantic pooled,
The Younger Dryas cold snap shocked and awed.
In Norway, glaciers reappeared on high,
Above the fjords where stoic Norse rule lapsed.
Then Carolina icebergs floated by,
As Greenland outlet glaciers collapsed.
Why would cold make this icecap melt, not grow?
Emotionless wind froze the Baffin Bay.
Warm currents thawed the ice tongues from below;
Without a shelf, the glac'er sped away.
  Today such currents threaten the Antarctic
  An outburst would be deluge, not cathartic.

Geology 42 759

Wednesday, November 05, 2014

Geosonnet 17

The ozone and peroxide in the air,
enriched in isotope O seventeen,
Pass on the spike reaction products bear;
This stratospheric label’s not marine.
If limestone sulphate bears this airy mark
deceitful proxy! geosaboteur!
Thus reconstructed oceans fade to dark,
Eliminating tales that never were.
A lithologic memory withdrawn,
Built on assumptions hereby disallowed
The dreams of times hypothesized are gone
Mere fanciful illusions, disavowed.
  A lab revealed the havoc smog did wreak
  Perhaps they need a microbeam technique.

Wednesday, October 29, 2014

Geosonnet 16

The strontium which weathers from the land
Is held by teeth and shells beneath the waves
Their creatures live, then die, interred in sand
with isotopes in stratigraphic graves.
The greatest dying Earth has ever seen
Initiated the Triassic time
Before the ants evolved, rock weathering
Was temperature dependent, leaching lime.
Warm mud in post-apocalyptic waste
Bereft of vegetation, washed away.
And Gaia, both hungover and disgraced,
Left complex biomes for another day.
  She sobered up in five or six epochs
  But those hard times forever changed the rocks.


Wednesday, October 22, 2014

Geosonnet 15

The ants which scuttle by between our toes
Dissolve the min’rals of the Earth we tread
The calcic feldspar, slipped under their nose
Ten trillion insects weather, pit, and shred.
The Himalayan mountains cool the Earth
Though mangroves and the grasses do their part,
But ants may do what was the work of turf
By min’ralizing CO2, they start
Evaporating seas in Neogene
Drying the Earth to suit their sandy hives
Anthropocene becomes the Formicene
The terraformic swarm constructs, connives.
  No human teamwork makes emissions slow
  Yet toiling ants sequester far below.


Saturday, October 18, 2014

Gender representation in Geology

A week and a half ago, I pointed out the gender imbalance apparent in the September issue of Geology.  My particular gripe was that it would be hard to achieve gender balance in my ongoing geopoetry series if issues (like the September one) had three or fewer papers by women authors.  With encouragements from commenters and the geotwitter rock stars, I had a slightly deeper look into what is going on with gender in geology, by recording the given name-assumed gender and author order for a year’s worth of Geology articles.  

In total, this included 239 papers with a total of 1164 authors.  The number of authors per paper ranged from 1 to 19. Of these authors, 64% were male, 19% were female, and 16% were initials. Initial authors excluded from the analysis; Most (57%) of them were on papers with six or more authors, so I assume that initialization was generally a space-saving exercise.

Looking only at uninitiated papers, the M/F ratio is 76.9% to 23.1%.  This is not too different to the professional gender balance quoted here (76% M) and is slightly better than the decade-old numbers on assistant professor hires (23% F), but is substantially worse than the (similar era) graduating PhD student ratio (38% F). So the implication is that the Geology gender ratio mostly reflects post-grad school anti-female filtering.

As for author order, the observed vs expected ratios (given the gender ratio) are shown in the figure below.  Due to the small size of the data set and the large number of individual categories, none of these deviations are statistically significant; the probability of sole author papers being seven M to zero F is about 14%- not high, but not enough to convict either.  The M/F of first authors, second authors, etc. was generally within a few percentage points of the mean ratio, and always within counting stats.


And a quick Monte Carlo* suggests that the probability of getting three or fewer female first authors in any particular issue is about 28% (see below), based on 10,000 random author list generations for 20-paper issues.

This is only a simulation, of course. It will take the Geological Society of America just shy of 800 years to put out their 10,000th issue.  Let’s hope that gender equity in academia has been achieved by then.

* Yes, I know there is an analytical solution, but simulations are more fun and quicker.