Auf Wiedersehen

By Thomas

This post is likely going to be my last one in a while. The reason for this is, that I’m now venturing in the final stage of my PhD and I have to focus on writing my thesis. Normally it takes a considerable amount of my time to write a blog post. So the only reason I might show up here in the next months would be if I just want to share an interesting read or if I want to let off some steam by writing down a rant in 30-X minutes.

Continue reading “Auf Wiedersehen”

Stupid hoodies

By Thomas

Sometimes you come across things that leave you speechless for a moment. Then you consider short whether it is worth the trouble to get upset about it. You shake your head and walk off. But then you come across this thing again …

The “thing” I am talking about in this case are hoodies soled by a group called “ANU Graduates Community”, not to be confused with the ANU Alumni community (I hope).

The first hoodie I came across said “I graduated from ANU. To save time, let`s just assume I`m always right” (Figure 1).

Figure 1: If you wear this I will assume something, it will have nothing to do with you being right though.

I shook my head and walked away from the idea of writing a post about it. After all, if people wanted to display their ignorance and the fact that they had not learned some essentials they should have learned at university, so be it. I was a bit worried that (some) ANU graduates might not understand that in an (ideal) academic discourse the formulated argument is what counts, not some authority you build up (e.g. by graduating from a certain institution). I was a bit more worried about the snobbish picture these hoodies would display to the general public. But hey, maybe the whole thing was some insider joke, or it was a good piece of irony that I just had failed to grasp.

Then I came across another hoddie this morning. It says “I graduated from ANU. I solve problems you don`t know you have in ways you can`t understand” (Figure 2).

Figure 2: Are you sure you graduated from ANU?

What the f … I mean … Really?! This hoodie raises the same problems as the first one: What did the person wearing it actually understood during the time at ANU and how is this message received by other people?

But there is another alarm clock that went off when I saw this one. But before I come to this let me make one thing clear:

I can totally understand that people are proud of graduating from ANU (or from any other institution for that matter) and there is no problem with that. But why do you have to use this pride to elevate yourself above others and be condescending towards them (“you don`t know […] you can`t understand”)?

In the best case that makes you an insensitive … person-I-don`t-want-to-have-anything-to-do-with.

In the worst case it is a sign that you get your self-esteem by belonging to a group of people which you elevate above others.

A human trait that accompanied us through all ages and has many facets.

A trait that can only bring forth misery and harm.

You might think I am a bit dramatic here. Yes, it is only a minor case. But in my eyes the well educated people coming out of university are (and have an obligation to be) the forefront of a modern society that ever pushes to get closer to the utopia of a world with equal rights and equal opportunities.

How can we ever get there, if even the graduates of a world leading university slip back into the old ways of group (i.e. “us against them”) thinking?

Rant is over.

Writing for the Reader

By Thomas

This is going to be a short blog post, because I actually want you to read a rather long article*. But I think every minute spend on reading it will be worthwhile your time. That is, if you do scientific writing (or going to do so).

The article explains how readers perceive a text and at which position in a sentence and/or paragraph they (i.e. all of us) expect to find which kind of information. If a text doesn`t concur with these expectations it will be really hard to understand for two reasons: (1) The reader puts emphasises on parts of the text that the writer didn`t inteded to emphasis and (2) the reader will “not get” the main point if it is hidden in a syntactically un-emphasised area of the sentence. To avoid these dilemmas the article gives tips on how to structure your sentences and paragraphs and illustrates these tips with different examples.

So without further ado:

The Science of Scientific Writing

Hope you will find it as helpfull as I did.

*Thanks to my supervisor for calling this one to my attention.


First Words

By Thomas

Six times the Apollo missions landed on the Moon (Yes, they did!).

Six times “first words” were spoken on the lunar surface. Most of them are not well known though.

What were they and how do they compare to each other? I put them into a sort of ascending (subjective!) order from “good” to “great”.

I`m sure your order will be different – let me know in the comments.

And it’s been a long way, but we’re here.
Alan Bartlett Shepard, Jr. , Apollo 14

Apollo 14 – The first golf swing on the Moon (by Alan Shepard)

The space race was won and the “successful failure” of Apollo 13 was probably still prominently in people’s minds. Therefore – when landing safely on the lunar surface again – this simple, down-to-Moon sentence set a good baseline for what was becoming more and more the focus of the Apollo missions now: Exploring and understanding the Moon.

Whoopie! Man, that may have been a small one for Neil, but that’s a long one for me.
Charles Conrad, Jr. , Apollo 12

as12-46-6777 thru as12-46-6780
Apollo 12 – The first landing on the intended landing site on the Moon

Well, what could you have said being the next in line and only 121 days after the “giant leap”? You would have had no chance to “beat” it. So why not use the occasion to prove that the first words on the Moon weren`t scripted by NASA. Conrad had made a 500 US$ bet with journalist Oriana Fallaci that he would make exactly this joke about his height while stepping from the ladder. Thus he showed that the astronauts were free to say what they wanted as their “first words”. He won the bet – but never got the money.

… as I step off at the surface at Taurus-Littrow, we’d like to dedicate the first step of Apollo 17 to all those who made it possible.
Eugene Andrew Cernan, Apollo 17

Apollo 17 – The first geologist on the Moon (Harrison Schmitt)

Flying and landing on the Moon is not easy. It needs a lot of woman- and manpower. The Apollo program employed up to 400000 people that made the whole enterprise possible. And they had to be paid. So every US-taxpayer was involved in making it possible too. And someone had to get the ball rolling to make it possible. I think it is fitting that the first words of the last Apollo mission were dedicated to all these people.

There you are: Mysterious and Unknown Descartes. Highland plains. Apollo 16 is gonna change your image.
John Watts Young, Apollo 16

as16-116-18573 thru as16-116-18581
Apollo 16 – The first landing in the lunar highlands

Prior to the mission the expectation was that the main geological units at the Apollo 16 landings site (the Cayley Plains and Descartes Highlands) were of volcanic origin. The mission showed that this expectation was wrong: The Cayley Plains as well as the Descartes Highland are large ejecta features, formed by rocks which were thrown to the location by gigantic impacts early in the lunar history. The first words on the surface during this mission therefore were quite prophetic. Although, you have to mention that short after landing John Young had already observed that something was strange with the rocks.1 So it was an “informed prophecy”.

As I stand out here in the wonders of the unknown at Hadley, I sort of realize there’s a fundamental truth to our nature. Man must explore. And this is exploration at its greatest.
David Randolph Scott, Apollo 15

Apollo 15 – The first car on the Moon

In my opinion the best first words due to their poetic quality.

“There is a fundamental truth to our nature. Man must explore. And this is exploration at its greatest.”

Could as well be the entry quote for a Star Trek movie or any other utopian works on the human strive “to boldly go where no one has gone before.”

Apollo 11 – The first bootprints on the Moon

Of course, missing in this little collection of quotes are THE first words. That is because you can`t really compare them to the others. Even if they would have been “This Moon landing is brought to you by Coca Cola” they would stand out, simply because they are THE first words. But of course I have to list them here, though not in competition with the other “first words”.

That’s one small step for [a] man, one giant leap for mankind.
Neil Alden Armstrong, Apollo 11

If mankind ever leaves this planet before annihilating itself, then these words will be carried with our collective consciousness to other planets, other stars or even other galaxies2. In a distant future, when all fairy tale books assigning humans a special place in nature by supernatural means will gather dust in the fantasy sections of libraries, this sentence will still be taught as a shining example for what really sets us apart – our will and ability to cross frontiers no one else3 could cross before.

The perfect line for the first “first words”!


1 “I wish I could tell you what kind of rocks those are Houston. But some of them are very white; and, doggone, if I could see…I’m not close enough to them, but…And I see one white one with some black…Can’t tell whether that’s dirt or not on it. But it could be a white breccia, if you believe such a thing.” Apollo Lunar Surface Journal

2 I`m sticking my neck far, far out here

3 “No one else” in this case means not other species. On this planet. As far as we know.

The next big leap

By Thomas

I´m sure most of you have already seen this movie in the last few weeks, but as we have Christmas, I thought I refer to it for those of you who haven´t seen it yet1:

Why do I think this is a fitting short movie for Christmas?

Well, some 2000 years ago, three guys followed a star to find the birthplace of the saviour of human kind – if you believe this kind of stories.

In the future, if human kind wants to be saved (from extinction) we will have to follow planets – not stars. And that´s what the video is about. Maybe, in another 2000 years, on a far off planet or moon in the outskirts of our solar system (or even another one), people will celebrate the day their ancestors left their home world “to sail forbidden seas”.

Going to other worlds – we´ve done it before:

The adventure to Earth´s silent companion might have eased our “everlasting itch” for now – I hope for not too long though.

But before we prepare for human kinds next big leap:

Frohe Weihnachten to all of you!

1 Thanks to Pierrot for bringing the “Wanderers” movie to my attention.

The Tunguska Enigma

By Thomas

It was an early June morning in 1908, somewhere in Siberia, as without a warning “the sky split in two and fire appeared high and wide over the forest”. That is at least how eyewitness S. Semenov recalls the event. (Wiki)

Continue reading “The Tunguska Enigma”

Communication Breakdown

By Thomas

Over the last week space science got a lot of publicity thanks to Rosetta and its sidekick Philae. ESAs successful attempt to land a spacecraft on a comet was all over the news. Apart from the news coverage, which the mission got thanks to the landing, you could and can follow Rosetta on Twitter or on the Rosetta blog, ESA is providing detailed information about the mission on their website and last but not least the use of videos explaining Rosettas mission and the ingenious short-movie Ambition got a lot of people excited about the mission. A pathetic hysteria raging over a scientists sense of fashion aside, it was an excellent example for science communication well-done. Or was it?

Continue reading “Communication Breakdown”


By Thomas

In science, a big part of your daily work is to critically assess other peoples and – more importantly – your own work. This can sometimes lead you into states of mind, which let you seriously doubt that everything is okay with said mind. I have ventured into such a state last week.

In particular it was a state of paranoia – paranoia about the abilities of past-Thomas to get anything correctly done.

Figure 1: Near Gaussian Normal Distribution of the life-long Trust-Yourself Coefficient (yes, that name is made up and it is not a thing)

You are probably familiar with the concept of past-, present- and future-self’s, especially if you have watched How I met your Mother. But just to avoid confusion, I will quickly explain:

If, let us say, I go out this evening and have a beer too much1, then I do this because it is not a problem for present-Thomas (aka “the guy who enjoys just-one-more cold beer”) but for future-Thomas (aka “the guy that wakes up tomorrow morning with a hangover”) who will curse the by then past-Thomas (aka “the guy who enjoyed the cold beer”).

But back to present-Thomas`s5 (aka “last week’s Thomas”) paranoia about past-Thomas`s (aka “last year’s Thomas”) “insufficiencies”.

Present-Thomas was comparing his own chemical data set with literature data and “just-to-make-sure-cause-something-seemed-a-bit-odd” was having a quick look at an Excel-Sheet which past-Thomas had used to do his data reduction6

Figure 2: Distribution of a PhD-students project-long Trust-Yourself Coefficient (still made up, but now it is a thing)

72 hours later: Present-Thomas had found a huge mistake in the data reduction sheet7, had glanced over past-Thomas`s notes on the problem, had fixed the problem, had found that this totally screwed up the out coming data, found that the problem actually was already addressed in the original data reduction sheet (just in another place) and found that this was actually explained in past-Thomas`s notes, if he would have read them and not just glanced over them. He also found that past-Thomas had indeed done a small mistake. For a few elements of the data set he had not chosen the highest quality ones. Mind you, he had worked out which data was of the highest quality, but for some reason had chosen the slightly lower in quality elements.

To use an analogy: If past-Thomas would have built a car, and present-Thomas would have noticed that it feels “a bit funny” while driving, present-Thomas would have taken the car apart, fit another motor in, got it out again, got the old motor back in, to then realize that past-Thomas had accidently put the spare wheel on and one of the normal wheels in the boot.

Figure 3:
Figure 3: Absolutly dysfunctional distribution of the Trust-Yourself Coefficient (it is a thing, look it up on the internet). If yours looks like this, you will not trust the person that prepared today`s lunch sandwich yesterday evening … especially if it was yourself … which is very likely in this case …

I think it is totally normal that we distrust our past self (Figure 1), and while growing older we more and more realize that our future-self will not understand what our present-self was actually up to. However, doing a PhD (or science in general) distorts this view (Figure 2) – and that can sometimes be a bit worrying, as you do not know how much distortion is good for you (Figure 3).

1 Of course I would never do that2

2 Do not look so reproachful, I am writing this on a saturday3

3 Well, I had the idea for this passage on saturday4

4 I think …

5 Thomas`?

6 The process which transforms the measurement from [insert used method here] into a sensible data set.

7 In hindsight I would term it “Pandoras Excel-Sheet”

Good News are Good News

By Thomas

We all know the saying “Bad News are Good News”, usually used by/for the media, referring to the phenomenon that “Bad News” normally get much more attention than “Good News”. Over the course of the last few weeks the plane disasters in Ukraine, Taiwan and Mali and the subsequent media coverage attest to this.

If our loved ones are on a trip, we might rather think of the saying “No News are Good News”, especially if they travel in region that doesn`t allow them to have 24/7 access to Facebook and Twitter.

When it comes to do a job, the principle is again a bit different. And while “Good News are Good News” is hardly a saying, it pretty much sums up the desired outcome that everyone hopes for when there is work in progress. Science is no different in this respect.

As a scientist you want to announce the discovery of the Higgs Boson, rather than explain to the citizens of several european countries that they paid 7.5 billion Euro for a machine that created a black hole that is now swallowing up Switzerland.1

As a scientist you want to announce, that the planet your curious rover is driving on has some interesting features. In the best case something that can be interpreted as possibly indicating that there was an environment on this planet that could in theory have hosted life. You don`t want to tell them that your orbiter crashed on the same planet, because someone thought “pound-seconds” is a sensible unit.2

As a scientist you want to tell your boss that you created a cure for Alzheimer, rather than a virus that will wipe out most of the human population, while at the same time creating highly intelligent apes, that will wipe the floor with the few human survivors. (Figure 1)

Figure 1: What is better than apes on horses? Apes on horses with guns!
Gee, how are they planning to top that in the next movie? Apes on motorbikes?
Source: Hollywoodreporter

Continue reading “Good News are Good News”

Changing the Pace

By Thomas

I don`t know why exactly – maybe it is for no reason at all, maybe because it is “winter” here in Australia, or maybe because I came across the video below a few weeks back – but these days I found myself quite often thinking back to the half-year of my life in 2009 that I spent in the beautiful city of Bergen in Norway.


I was there due to the European exchange program “Erasmus” to study for one semester. So yes, classical exchange semester right there. No worries, I`m not going to bore you to death (I hope) with an account of my activities there.

While these memories are very dear to me, I know that they`ll – at best – will be of medium interest to you.

So I will not tell you about the awesome time I had with the group of people working at the local student club (Klubb Fantoft).

I will not tell you about the time when one of my best friends visited me and we ended up in an Irish bar on St. Patrick’s Day (where else?) and we had much too much Guinness.

I will also not tell you about my trip to Trondheim, a city with a wonderful city centre of old wooden houses in the shadow of an impressive cathedral.

I will not … well you get the point. I will not write about specific things that happened to me while I was there.

What I want to write about is what (for me) turned out to have the biggest impact in the long-term:

It all starts with a “negative” side of this exchange semester.1 At least something I considered negative months before I even got to Bergen. I had enrolled for the exchange while I was still in my undergraduate studies of chemistry. But by the time it came down to finalising the details, I had slightly changed course and was enrolled in a master’s program about mineralogy and material science. This program was set on the border between inorganic chemistry and geology. As the University of Bergen had both, a chemistry and a geology department, I did not expect big problems to find some courses to take.

Well, I was wrong. The advanced chemistry courses would have provided a rich source, if I would still have been enrolled in a chemistry program. The advanced geology courses required a geology background that I lacked. In the end I settled for an undergraduate course in Oceanography2, and graduate courses in Microscopy3 as well as Isotope Geochemistry4.

And there was another problem that I realized relatively late:

The new semester in Norway started with the new year, while the old semester in Germany was still running into February. This meant I couldn`t take most of the exams for the old semester and I would be back too late to catch up with the new semester at home. So that was how the situation looked for me before I even went to Bergen:

I would effectively lose two semesters at home and wouldn`t be able to compensate much of this time with the courses I could do abroad.

And that was the best thing that could have happened to me.

Bergen in winter at day

Why? Because it forced me to change pace. Until this point I thought this to be a bad thing. My CV was a neat sequence from school to military service to undergraduate degree without any unnecessary interruptions or prolongations.5 And stupid as I was, I thought I had to finish my master’s degree in two years while quenching an exchange semester in between, else … yes, what was I thinking would happen?

In retrospect it`s hard to say what really kept up this (mostly self-imposed) pressure: It was something along the lines of being intellectually not worthy of a graduate degree if you can`t finish it in the pre-set time6 and the stupid assumption not to be able to get a job or into a PhD program if you don`t finish all your studies exactly in time.

But the details that I worried about are actual not that important, it is more the general direction: I worried (too much) about the Undiscovered Country!7 And there are only so much things that we can know and influence about it. Accepting that there are a lot of things ahead that we can`t control takes a lot of your shoulders and sharpens the view on the things you can actually do something about.

Okay, I start to sound like a walking fortune cookie. The point I try to make is, even though something might be common (fortune cookie) “wisdom”, it might need an event that forces us out of our comfort zone, to get this “wisdom” really into our heads. And better we learn life’s lessons from small stumbling blocks than when the shit really hits the fan.8

Bergen in winter at night

And of course, these lessons will not completely change who we are!

I still worry about the future. I still feel imposter syndrome from time to time. I worry about getting my PhD done. At the moment I worry a lot about a paper I`m writing on.

It is not about having no fears about the future. It is about finding something to balance them out with. And for me these six months in Bergen are one very good counterbalance at hand – casted as a concentrate into the memory of a single evening:

2nd of January 2009 – Just a few hours after arriving in Bergen: I decide to walk to the city centre. The city is lit with thousands and thousands of window lights, reflected from the all-covering snow – filling the whole valley with a golden shine. The landscape was forged by the irresistable force of the ice ages long ago, while the city – that huddles between the mountains – seems a fragile construct from human hand, merely existing for the blink of an eye. And while I stump through the snow, time slows down. If feels like it`s not me who`s changing the pace, but the world around me.9

Of course this memory is massively pimped and distorted by my subconsciousness. But it is a place in my heart10 I can retreat to. A place that reminds me that the future might be an undiscovered country – but that the only thing we need, to forge ahead through whatever awaits us, is the willingness to change our pace from time to time.


1 Negative side of an exchange semester – yep, first world problem coming your way.

2 Visiting a renowned Marine Science University, it seemed a nice field to have a glimpse at.

3 The only one really fitting with my master program, and even though mainly taught in Norwegian (which I don`t speak), one of the best courses I`ve ever had – might have had something to do with the fact it was mainly a practical course, and you`re looking at beautiful minerals all the time.

4 Which I barely passed. Considering that`s one of the main things I do now in my PhD project … well, irony.

5 All hail to the neoliberal dogma of the perfect human resource!

6 I guess that qualifies as imposter syndrome.

7 For those of you who haven`t seen or don`t remember Star Trek VI: … the Future!

8 Ever since I first heard this saying, I tried to find a way to put it in a post.

9 Seriously, if you ever have the possibility to go to Bergen in winter, do it. It`s the most “magical” place I know of. Well maybe rivaled by Lisbon’s Baixa (city center) in a warm summer night at four in the morning …

10 Well, my brain …

ArtUp your Science

By Thomas

A few weeks back I wrote about the “epicness” and literary quality that is hidden behind the technical terms in which scientific ideas (i.e. hypotheses or theories) are presented.

A picture is worth a thousand words“, so a good way to present your scientific idea to the community are figures. Of course, figures in scientific papers (e.g. data plots, model visualisations, maps) are subject to the same modus of presentation as a scientific text:

Anxious to be accurate, clear and as plain1 as possible.

I often come across figures in papers, which not only tell their part of the story very well, but also look like they were done by a professional designer.

Up to and through my master thesis I always used a combination of Excel and relative simple graphic programs to create my figures. Consequently, they often looked like I let my 5-year-old self do the job.

To be able to create better looking figures in the future I started using Adobe Illustrator a while back. To get a feeling for the program and to learn the basic tools2, I decided to create a map of the Apollo 16 landing site, from which most of my samples are coming from.

Using images taken by the Lunar Reconnaissance Orbiter Camera at different times of the day and a Traverse Map of the Apollo 16 mission I created Figure 1. I marked different craters (red), added the traverse of the astronauts during the mission (orange) and marked the sample locations of the samples I`m working on with different colored dots.

Apollo 16 Area_v1-02
Figure 1: Apollo 16 Landing Site.
Red Areas: Craters; Orange Lines: Apollo 16 Travers Paths; Colored Dots: Sample Locations

Not very impressive, but a start. The nice thing with Illustrator is, that you can save every detail separately and change their appearance later. So I hope, when I learn to handle to program better, I can go back and improve the figure more and more.

But now to the fun part: As I mentioned, the program is new to me. So I started browsing through the menu and play around with the different options. And there are a lot of options – probably more aiming at people doing professional graphic design.

Nevertheless, I started applying different filters, graphic features etc. to the various layers of my figure. The result (Figure 2) can`t probably count anymore as a geological map of any sort, but looks quite “arty”.

Apollo 16 Area_ArtedUp-02-02
Figure 2: ArtedUp Version of Figure 1.

I guess a lot of you have some nice Illustrator files lying around. So if you want to let your creative site out for a walk, dig up some files and Art’em’Up!

If you are pleased with the result, feel free to send them to, and we will display them here.


1 That doesn`t mean scientific figures can`t be detailed. They just eradicate every unnecessary detail.

2 Thanks for the introduction, Paula!

A Brief History of the Moon

By Thomas

Most of my posts here on the blog are related to the Moon, which stems from the fact that my PhD project is on lunar samples. I therefore could devote a big deal of my time in the last two years to read about, what a lot of people, much smarter than me, found out about the Moon.

That means, when I write about some new and/or interesting piece of research about the Moon, I do that on the rag rug of information, that I have mentally stitched together in my head. I try to provide the necessary information, why the topic I`m writing about is “new” or “interesting” (and I hope I succeed at least from time to time).

One of the most vital pieces of information normally needed, is the time or respectively the timeframe of the topic in question. A while ago, I came across the Video “Evolution of the Moon” from NASA that provides a nice summary of key events in lunar history. I think it can provide a nice Guideline through Lunar History, and allow you to place the topics I`m writing about in a broader context.

Source: NASA

The video starts after the formation of the Moon through the Giant Impact of a planet called Theia, about 4.5 Billion years ago. At that time the Moon was likely covered in a Magma Ocean. When this Magma Ocean cooled the Crust of the Moon formed on top.

The oldest feature we can identify on the Crust is the South Pole-Aitken basin, formed by a big impactor slamming into the Young Lunar Crust on the southern farside, that might have even had big effects on the nearside of the Moon. The video states that the impact happened “~4.3 billion years ago”.

You can mentally format the “~” in a bold font and underline it – twice.

The age of this basin could be 4.4 billion years or 4.0 billion years for all we know. It`s actual age could tell us a lot about the next important time frame:

The “Basin Formation/Heavy Bombardment” somewhere between ~4.1-3.8 billion years ago.

This “Late Heavy Bombardment”1 might have been caused by impactors that were the leftovers of the planet formation in the Early Solar System, which randomly hit the Moon over a long timeframe of a few hundred million years.

Or they swept in a wave (or several waves) through the Inner Solar System, caused by migration of the Big Planets in the Outer Solar System. In this case the impactors would hit in a much shorter timeframe (million to tens of million of years), the so-called “Lunar Cataclysm”.

The impacts of the Late Heavy Bombardment formed large basins, that subsequently were flooded by lava, rising up from the still hot Interior of the Moon. The result of this “Mare Volcanism” are the dark areas we still see on the Moons surface today.

Over the next 3.8 billion years the Moon was (and still is) constantly bombarded by meteorites, forming numerous smaller craters. The youngest ones can be identified by the rays that extend from them. These rays are formed from ejected material. The ray systems of older craters were destroyed through the following bombardment.

Of course, the events were not as distinct as in the video. Small Meteorites bombarded the Moon from the Beginning, but they had a minor effect during the time of the big impacts. Volcanism occured as soon as the Crust had formed. The video shows the dominant force acting at the timeframe in question – and it does a very good job at that.

1 “Late” because it happened after the formation of the Lunar Crust.

The Teeny-Tiny Trace of a Giant Impact

By Thomas

The Moon formed in a Giant Impact of a planet called Theia with Earth (Figure 1). You can find a nice simulation of this event at the end of this post or watch the orginal here. In a post a few weeks back I mentioned that there are some problems with the details of this theory and that I would write about that soon.

The Giant Impact
Figure 1: The Giant Impact
Source: National Geographic

As a paper published last week in Science [1] is exactly about that topic, I thought it is time to follow up on this promise. The mentioned paper shows that technology has developed far enough to allow science to tackle the problems lurking within the Giant Impact Theory. Responses in the media (e.g. here, or for german speakers here) about the paper seem to focus on the fact that the paper supports/confirms the Giant Impact Theory.

Yes, the results are in agreement with the theory and therefor support/confirm it!

But to focus on this, implies that the main question we are facing, when it comes to the Moons origin, is:

Was there a giant impact?

Of course one is allowed to ask this question. However, in science this question is only taken seriously if you`ll offer an alternative hypothesis, that works equally well or better in hindsight of the known facts. When it comes to the origin of the Moon, all other origin hypotheses have already been discarded for various reasons and to my knowledge there are no rival hypotheses to the giant impact left.1 The Giant Impact is a fact, and was one before this paper!2

The question is not: Did it happen?

The question is: How did it happen?

The Giant Impact Theory came a long way since it was first proposed in 1975 [2]. It solved a lot of problems regarding chemical similarities and differences between Earth and Moon. But in recent years it got stuck in a bottleneck.

What had happened?

Measurements of the elements oxygen, chromium, titanium, tungsten and silicon had shown that the ratios between the isotopes of those elements were the same in the Earth and the Moon. [3]

Why was that a problem?

Those ratios are fundamentally different in other rocky bodies in our solar system like the asteroids and – more important – Mars. Therefor it is likely that Theia and the Proto-Earth (the Earth before the Giant Impact) differed in these isotopic signatures as well. If that was the case, the standard model of the Giant Impact would predict that those ratios would be different in the Earth and the Moon (Figure 2).

Figure 2: Different Models of the Giant Impact.
Source: Science

Different changes in the model were proposed to achieve the similarity in isotopic ratios, but all of them require very special conditions, such as a fast spinning Proto-Earth or Theia being the same size as Earth (Figure 2) or complex processes following the impact [3-5].

Or maybe Theia didn`t had a similar isotopic signature to the Proto-Earth? For that line of thinking we would have to revise what we assume about the distribution of isotopic signatures in the solar system. That would be a great and enlightening thing to do, but would require samples from a rocky planet other than Mars – preferentially our twin planet Venus. [3]

So what`s the great news?

Actually, the great news are small – very small. That best describes the differences between the isotopic signatures of Earth and Moon rocks which now were uncovered.

But didn`t I said above that there were no such differences?

Indeed, but I should have added “within error”. The error is used to describe the area of uncertainty around a measured result. For example, I know I`m 185 cm tall. But I have never measured that very accurately, so it could easily be that I`m actually 1 cm taller or smaller. The 1 cm is the error on the measurement of my height. If I now meet a person who has measured his or her height (equally lax) to be 185 cm, we would have to conclude that we are equally tall (within error), even though he or she might be 186 cm and I only 184 cm. How can we find out? We have to measure more precise, let’s say with a mm-scaled tape.

In a nutshell, that is what the new study did – measured more precise. They found that when you compare 1 million oxygen atoms on Earth to 1 million oxygen atoms on the Moon, you`ll find that 123 of those atoms are different isotopes4.

This means a great relief, for some reasons:

a.) It means there is a difference in those isotopic signatures and we don`t have to invoke very special conditions5 for the Giant Impact.

b.) It promises that we`ll find similar differences in the other isotope systems apart from oxygen.6

c.) When we know how the Earth and the Moon differ, we can infer more on the nature of Theia, the Proto-Earth and the details of the impact.7

And that is much more, than just to confirm that there was a Giant Impact!


A simulation showing the Giant Impact.
Source: Nature

1 That doesn`t mean someone might come up with a new one in the future.

2 Imagine the media would title every article about new advances in evolutionary biology with “Evolution Confirmed!” – Technically true, but still missing the point.

3 If we`re including the error: 9-15

4 Don`t worry about the isotopes. It basically is like two boxes filled with 1 million red and blue balls, where one box has 12 more of the blue balls. Even finding that out, would be hard. Now imagine that on an atomic scale, where you can`t “see” the atoms and where the difference between the balls is the equivalent of blue and very-slightly-darker blue.

5 Special conditions are often a sign that there`s something wrong with your theory.

6 Oxygen isotopes were the first to indicate the similarity-problem [6], it`s good that they make up by showing a way out.

7 In the presented paper, the authors speculate on the basis of their data, that Theia might have had a enstatite chondrite composition, which is material we find in the asteroid belt. But we have to see what the future (and other isotopic systems) will bring.


1. Herwartz, D., et al., Identification of the giant impactor Theia in lunar rocks. Science, 2014. 344(6188): p. 1146-1150.
2. Hartman, W.K. and R.D. Davis, Satellite-Sized Planetesimals and Lunar Origin. Icarus, 1975. 24: p. 504-515.
3. Canup, R., Lunar conspiracies. Nature, Vol. 504, 2013(7478): p. 27.
4. Elkins-Tanton, L.T., Planetary science: Occam’s origin of the Moon. Nature Geoscience, 2013. 6(12): p. 996-998 (2013).
5. Clery, D., Impact Theory Gets Whacked. Science, 2013. 342(6155): p. 183-185.
6. Wiechert, U., et al., Oxygen isotopes and the moon-forming giant impact. Science, 2001. 294(5541): p. 345-348.

Vikings vs Dinosaurs

By Thomas

As many, I was fascinated with dinosaurs as a kid. My childhood memory is filled with pictures of (featherless!) monsters as in Figure 1. For quite a while I wanted to become a “dinosaur-explorer”, after all, it seemed to be quite an easy job (Figure 2) and fun. What fascinated me the most though, were not the creatures themselves but how they came to an end:

A silent killer, stalking through the endless darkness of space, approaching Earth and then – WHAM!!!

From one second to the other – Death and Destruction.

Figure 1: Unfeathered (and slightly obese?) T-Rex: Cool! But maybe also feeling a bit cold? Feathered or not, those creatures stay fascinating.

That at least, is the main theory that explains the last of the five (known) major extinction events in the history of life on Earth. I didn`t knew it at that time, but this theory was only a bit older then myself and was born in 1980 [1-5]. Despite the childhood fascination, I didn`t became a palaeontologist1 but ventured into chemistry and mineralogy for my studies. A few years later I was working on my master thesis, trying to determine how fast natural occurring glasses cool down. The glasses in question were Impactites – Glasses formed from rocks that are molten during an asteroid or comet impact on Earth.

Figure 2: Find some bones. Draw some sketches. Give it a name.
Science in the good old days.

There I was, by coincidence, working on samples, formed by events like the one that obliterated around 75% of all species some 66 Million years ago. And while the problem I had to solve for my thesis was more of a technical nature2, the old fascination with impacts of extra-terrestrial bodies crept out of some corner of my brain, where it had slept for years. I started reading more about the processes and effects of impacts3, and in doing so, came across the early literature that linked the dinosaur’s extinction to a massive impact event. While it was fascinating to read through the original papers that gave rise to the impact theory, I couldn`t help but notice, that the description given therein, were (compared to my imagination) a bit dull:

In brief, our hypothesis suggests that an asteroid struck the earth, formed an impact crater, and some of the dust-sized material ejected from the crater reached the stratosphere and was spread around the globe. This dust effectively prevented sunlight from reaching the surface for a period of several years, until the dust settled to earth. Loss of sunlight suppressed photosynthesis, and as a result most food chains collapsed and the extinctions resulted.” [1]

When writing a scientific paper, one is bound to some degree of “dullness”, as a paper gets its credibility from carefully chosen and precise wording. Unfortunately this leads many people to see science as a rather technical or even boring affaire. The problem is, that they only see the “end product” of a very long and creative thought process.

Luckily, from time to time, we can get a glimpse on the imaginative power, that stands behind a scientific theory, when distinguished scientists find the time to write popular science books. As it so happens, Walter Alvarez, one of the “fathers” of the “dinosaurs got whacked by impact” theory [1], did exactly this.
In “T. rex and the Crater of Doom” he gives an account about how the whole impact could have happened. Assuming the impactor was a comet, he describes it as follows:

“It was a ball of dirty ice, spewing out gases boiled off by the heat of the Sun, and it announced impending doom with a shimmering head and a brilliant tail splashed across half the sky, illuminating the night, and finally visible even in the daytime as Armageddon approached.”

Such difference in wording, compared to the scientific account further above. A depiction which paints a vivid picture in our minds. I don`t know why exactly, probably because it is a story of a world coming to an end, but I felt reminded of another “End-of-the-World” description: Namely, Ragnarök, the destruction and end of the world in Norse mythology. It is described in the poem “Völuspá” in the Poetic Edda (a collection of poems) from Iceland. There the approaching doom is depicted in form of the fire giant Surt:

“Surt comes from the south, and fire he brings.
Branches and twigs to ravage;
From his sword light blazes to be a sun
To all the gods of carnage.”

Note, that I do not want to draw any connections in regards to the content of both descriptions (e.g. that Ragnarök is inspired by an impact event). It`s the similarity in verbalism:
Both accounts are depictions of looming doom that trigger the label “epic” when I read them. Of course, that might not be the case for you, “epic” is a pretty subjective label. So let me compare the two accounts a bit more.

Alvarez describes the world after the big impact as follows:

“Where only the day before there had been fertile landscapes, full of animals and plants of all kinds, now there was a vast, smoldering netherworld, mercifully hidden from view by black clouds of roiling smoke.”

While the Vikings thought, after gods, giants and men had their last fight:

“The sun grows black, earth sinks in the sea,
The bright stars fade from the sky;
Fires and fumes are raging; to heaven itself
The flickering heat leaps high.”

In both cases, the world (or at least life) seems to have come to an end. But as we know, life on Earth didn`t ended with the impact, and so Alvarez finishes with:

“Our nostalgia for the lost world of the Cretaceous is tempered when we realize that it was a world that held no place for us — for large mammals. Our horror at the destruction caused by the impact that ended the Cretaceous is eased by the understanding that only because of this catastrophe did evolution embark on a course which, 65 million years later, has led to us. We are the beneficiaries of Armageddon.”

And of course in Norse mythology the world makes a comeback after the “End of the World”, with a similar optimistic tone to it:

“Yet I see earth rise from the waves again,
Green now for evermore:
The waterfalls flow, and the eagle flies
Hunting fish along the shore.”

So we see, what goes on in a scientists imagination, when thinking about a theory, is likely much more powerful than what he brings to paper later. And it even might be as good a story as we find in other literature. And those kind of stories are the ones which our brain soaks up like a sponge.

Figure 3: Definetly an epic story! The scrap metal from the Alien-machinery even would account for the Iridium anomaly. Still not a very feasable theory.
From: Imgur

But for a scientific text these stories have to be told with neutral and technical terms. Remember though, when we read those texts, nothing stops us from reversing this process and adding some “epicness” to the story, to give our brain something to hold on to.

We just need to let our imagination a bit loose. Not tooooo much (Figure 3) though!


1 A more fancy way of saying “dinosaur-explorer” that I learned while growing older.
2 Basically: Can this particular method be adapted to impactites, and if yes, how fast did these glasses cool down? It didn`t worked out for all samples, but we finally could apply the method to an impactite from the El`gygytgyn crater in Russia [6].
3 The book that really got me hooked was Traces of Catastrophe. Even though a few years old by now, it gives a very good introduction into the field of impact cratering.


1. Alvarez, L.W., et al., Extraterrestrial Cause for the Cretaceous-Tertiary Extinction – Experimental Results and Theoretical Interpretation. Science, 1980. 208(4448): p. 1095-1108.
2. Smit, J. and J. Hertogen, An Extraterrestrial Event at the Cretaceous-Tertiary Boundary. Nature, 1980. 285(5762): p. 198-200.
3. Hsu, K.J., Terrestrial Catastrophe Caused by Cometary Impact at the End of Cretaceous. Nature, 1980. 285(5762): p. 201-203.
4. Ganapathy, R., A Major Meteorite Impact on the Earth 65 Million Years Ago – Evidence from the Cretaceous-Tertiary Boundary Clay. Science, 1980. 209(4459): p. 921-923.
5. Kyte, F.T., Z. Zhou, and J.T. Wasson, Siderophile-Enriched Sediments from the Cretaceous-Tertiary Boundary. Nature, 1980. 288(5792): p. 651-656.
6. Rantzsch, U., et al., The cooling rate of El`gygytgyn impact glass. Meteoritics & Planetary Science, 2013. 48(7): p. 1351-1358.

Money for Nothing

By Thomas

The recently released budget plans of the Australian government have been heavily debated over the last few weeks. I will not bother you with my (general) opinion about the budget (or the current government) as

a.)  People, more skilled in writing, can do that much better.

b.)  This blog should be mainly about Research and PhD student life and not political issues.

c.)   I don`t feel like driving my blood pressure too high today.

What I want to talk about is something that is affected by the budget and makes a crucial impact on (PhD) student lives as well: The price of education.

Before I discuss this, I just find it fair to give you some information about me, that can help you to understand where my viewpoint is coming from and where my opinion might be biased the one way or the other:

I`m from Germany and received my whole education (before starting a PhD) there. That means, in a country where education (yes, even studying) is generally free (of cost!) for everyone. Of course, there are problems with the german education system as well, but the basic idea that education should be free to everyone is something that I feel very strong about.1
At the moment I`m in a PhD program at ANU, and this is only thanks to Australian scholarships that cover my university fees and living costs. And I`m deeply grateful for this opportunity.

Now, you might think that the latter point might have told me the lesson, that (in theory) in a system, where students have to pay a fee for studying, everyone can study (through credits, scholarships, savings) regardless of their financial starting situation. And that therefore these systems are as good as non-fee university systems.

I agree that this statement would be true, in a perfect world, where every student has either enough savings, can get a scholarship or has no problem to get and to pay off their student loan.

I yet haven’t been convinced we live in such a world.

Even if, it would still make a difference for someone who thinks about studying, if they have to take the financial risk of a student loan (or burning a big hole in their savings) into account, or whether they don`t have to bother about that.

Anyway, I actually don`t want to discuss the pros and cons of fee and non-fee education systems here. I can see why a fee-system is very attractive for Australia with all those cash cows around, ready to milk. These cash cows being countries (e.g. China, Chile) who (more or less) happily pay the fees to send their students to esteemed Universities in Australia.

For me this shows the mind-set behind the fee-system: Education as a business.

If, at least, this system would provide solid funding for the education of domestic students. They`ll probably going to need more support when the university fees start to skyrocket

And that is what baffles me the most – exemplified in comments like this from the ANU`s Vice-Chancellors Blog:

“At present, the student contribution to their education is fixed by the Commonwealth and varies by discipline. From 2016 universities will be able to set the amount of the student contribution. There will be no cap on this amount provided it does not exceed the amount which the University charges international students in that same discipline.”

That`s a thing that won’t go in my head: The goal of a university fee is that the students pay for their education, right? Or did I misunderstand the concept? Now, shouldn`t that mean, that your own students should only pay what their education costs? That one charges more to foreign students, okay, that`s the “Edcuation is a business” approach. But your own students – they are an investment in the countries future.

But now it can happen that domestic students have to pay the same as foreign students. In my opinion that will mean one thing:

They`ll pay more for their education than it costs!

Where will that surplus of money end up?

Presumably in the other area, universities are there for: Research2.

Don`t get me wrong: More money for Research? Superb!.

But I think it should come from the institutions (e.g. the state or companies) that are interested in the results.

I can follow the internal logic of a system where you require students to pay for their education (even though I personally don`t think it`s the best solution).

What I can`t, is to see the rationale behind what (I think) is looming at the horizon:

A system where students have to subsidize research, because the government doesn`t want too fund it properly!


1 And apparently I`m not the only one who feels that way.

2 Of course not directly. But there are a lot of things in a university that are needed for education and research as well (e.g. infrastructure, staff). If you assign a bigger amount of money for these basic costs to the education sector you effectivly subsidize the research sector of the university. I could be wrong with that, so if someone knows more about where this surplus of money is going to go, please share that information in the comments.

“Climate change can be explained using simple water cycle models that combine wind turbines and the great pacific garbage patch” says inuit dentist while visiting the driest place on Earth.

By Thomas

Confused by the headline of this post? Don’t be! Just read on, it will become clear in a second.

About a month ago, I took over the administration of this blog from Claire, who did an excellent job on this over the last year or so. My main task is to put the posts on the blog and make sure that we reach the goal of at least one post per week (by persuading1 people to write a post).

To get familiar with the blog and find out about the different administrative tools at hand I used the classical “Try-and-Error-by-Clicking-on-every-possible-Button” approach. This led me to the “Stats” site that records for the blog. There you can see, for example the views by country (Fig. 1), that we currently have 500-700 views per week or that November 2012 was the month with the most visits (8,834) in the history of the blog.

Fig. 1: Views by country for the oncirculation blog from 25.02.2012 to 07.05.2014. Australia clearly leads (surprise!) with 46,601 views ahead of the US (30,652) and the UK (7,674).

However, the most interesting part of the “Stats” site is the one that shows you the search terms that people used to end up on the blog. And now you can probably already guess how that headline of this post came to life: By combining popular search terms that lead people to our blog.

It is not too surprising that search terms like “climate change” (Nr. 1; 2,331 views), “simple water cycle models” (Nr. 3; 696 views), “wind turbines” (Nr. 4; 547 views), “great pacific garbage patch” (Nr. 6; 403 views) and “driest place on earth” (Nr. 12; 184 views) refer people to this site, considering what the bloggers write about here.

On the other hand, terms like “inuit” (Nr. 2; 1,307 views) and “dentist” (Nr. 7; 376 views) are a bit puzzling at first. Having a look at the archive of the blog, which contains posts like “An Inuit view on Arctic climate change” and “Why giving a presentation is like going to the dentist” solves the mystery though.

Probably most of the people, that used these search terms, didn`t originally intend to end up on this blog (or a science blog for that matter). Especially in the latter case. I picture 376 persons out there, who typed (with agony in their mouth) “dentist” into their preferred search engine, clicked on a link and thought “WTF!!!”. But maybe some of them read the article while they were waiting for the appointment with their dentist?

So if you plan to write a blog post2, get creative when it comes to the use of words, especially in the heading.

And to close this post, a little list of weird and funny search terms that lead people here:

“why is it so windy” (52 views)

“rock licker” (18 views)

“the end of the world 2012” (15 views)

“why is it so windy today” (15 views)

“slave driver” (11 views)

“dart miss” (10 views)

“cheese” (9 views)

“largest kangaroo ever” (9 views)

“why all the weird weather” (9 views)

“diatoms from space” (8 views) … sounds like an awesome Trash-Movie-Title

“epic fail” (6 views)

“two bunnies gif” (6 views)

And one search term that should lead much more often to this site:

“great earth science blogs” (views 7) 😉


1 Read: … begging …

2 If you are a student at RSES, then YES, you definitly plan on doing that!

The Moon’s New Clothes Mantle

By Thomas

The 12 people who walked on the Moon are the only humans who ever set foot on another world1. Though this world is on average more than 380.000 km away from ours, the rocks brought back by the astronauts revealed an interesting fact: While the astronauts literally travelled very far away from home, they figuratively slammed their flag in yet another piece of the Earth.

Moon rocks are in many respects similar to Earth rocks. The only explanation we have so far which sufficiently explains this similarities is the Giant Impact Theory2: A mars-sized planet (named Theia) collides with the Proto-Earth, and the Moon subsequently forms from the material that is ejected into Earth`s orbit by the collision. In this scenario the Moon is formed from mainly Proto-Earth material. Welcome home guys3.

Figure 1: The Earth`s interior. From Wikipedia.

We know a lot about Earth`s surface. After all, we can easily walk around and pick up rocks nearly everywhere4. And even better, we also know quite some stuff about its interior through the information we get through earthquakes and rocks brought up from the deep through volcanism. We know the Earth has an iron rich core (divided into a solid inner and liquid outer core), a stiff inner mantle and a rigid outer mantle surrounded by a thin crust (Figure 1). We have a similar yet much less detailed picture of the lunar interior (Figure 2). And we think that all other rocky planets (Mercury, Venus, Mars, Pluto), dwarf planets (Pluto, Ceres …), and for that matter exoplanets of similar composition and size have similar structures. The main principle causing these structures is that heavy elements (such as iron and nickel) sink to the centre of a planet to form the core while lighter elements are preferentially found in the outer part of the planet.

Figure 2: The Moon`s interior. Yes, there were even some moonquakes measured by the equipment set up by the Apollo missions. From Wieczorek et al. (2006).

But we have to be carefully to not overstress when we apply our knowledge of the Earth to similar bodies. A dominant mineral in the Earth`s upper mantle is olivine. So it`s fair to assume for a start that it is also abundant in the Moon`s upper mantle5 (Figure 3). This olivine would be excavated by big impact events on the Moon if they penetrate deep enough. A study (Melosh et al., 2014) presented at this year’s Lunar and Planetary Science Conference showed by modelling that the South Pole-Aitken (SPA) impact event most certainly excavated mantle material. Therefor there should be a substantial amount of olivine in the area around the impact basin where the ejected material from the upper mantle came to rest. Luckily6 olivine is one of the minerals that can be detected by NASA`s Moon Mineralogy Mapper (M3 or M-cubed). So the scientist used the data set provided by M3 to have a look on a region that should be dominated by SPA ejecta. What they found was nearly no trace of olivine but a dominant signature of another mineral also found in the Earth`s mantle – orthopyroxene. This indicates that the lunar upper mantle might be dominated by orthopyroxene in contrast to the Earth`s olivine dominated upper mantle.7

Figure 3: A possible model for minerals in the Moon`s interior. From Wieczorek et al. (2006).

If this hypothesis turns out to be correct, how could this be explained, taking into account that Earth and Moon started with a similar chemical composition after the Giant Impact?

The experts on that matter will probably find a detailed explanation in due time. I`m not an expert on this, so please consider the next paragraph wild speculation:

Two main factors that control which minerals are formed from a given chemical composition are temperature and pressure. And they might have been much different in the lunar upper mantle at the time it crystallized compared to Earth. This is due to the mass difference between the Earth and the Moon8. This means the pressures that can be reached within the Moon are lower than on Earth. Also the lower mass affected the thermal history of the Moon so that it cooled down much faster than the Earth. Therefor this two key factors for the formation of minerals were probably different at the time of crystallization of the lunar upper mantle compared to Earth`s upper mantle.

These key factors will also be different in other planetary bodies and therefore we might see similar effects there too. Melosh et al. (2014) themselves refer to the asteroid “4 Vesta” on which similar studies revealed substantial amounts of orthopyroxene in material believed to be from the upper mantle as well (McSween et al., 2013).

Libourel and Corrigan (2014) generally point out that there is a scarcity of olivine dominated material in asteroid observations: Scarce if you assume that asteroids differentiate into an iron-nickel core and an olivine-dominated mantle. This of course is the same (Earth-centered) assumption that brought us into trouble with the lunar mantle as well.

Looks like the Moon`s New Mantle might start a new fad.9

1) While the 6 command module pilots were probably the humans who were farthest away from any other human being – ever.

2) There are some problems with this theory. Therefor its details are under revision at the moment. I hope I`ll be able to write something up on that soon. So stay tuned.

3) Man, that`s a bit like traveling over a dangerous ocean to stick your flag into a New World just to discover some (distant) cousins of yours are already there. Uhm, there seems to be a pattern here …

4) Well, on the continents that is. And if the region is not too dangerous. And if you have enough founding to go there.

5) Especially as there is the possibility that a lot of olivine from the lower mantle might have been ended up in the upper mantle through a massive mantle overturn. But that`s another story.

6) Meaning: Due to careful mission design …

7) I`m almost certain that I read a recent paper before going to LPSC that similarly suggested that something funny was going on with the lunar mantle (and maybe even mentioning that there was less olivine than expected). I thought it was in Spudis et al. (2014) but going back to that paper I can`t find any mentioning of that matter. So maybe I just mixed that up as I was reading the Melosh et al. (2014) abstract and the Spudis et al. (2014) paper around the same time, or there was another paper. So if anyone out there remembers reading something on that matter, please let me know.

8) The Moon has only about 1/80 of the Earth`s mass.

9) I apologize for the massive use of footnotes in this post. And yes, I`m a bit sad that I didn`t made it to 10 😉


Libourel, G. and Corrigan, C. M., 2014. Asteroids: New Challenges, New Targets. Elements 10, 11-17.

McSween, H. Y., Ammannito, E., Reddy, V., Prettyman, T. H., Beck, A. W., De Sanctis, M. C., Nathues, A., Le Corre, L., O’Brien, D. P., Yamashita, N., McCoy, T. J., Mittlefehldt, D. W., Toplis, M. J., Schenk, P., Palomba, E., Turrini, D., Tosi, F., Zambon, F., Longobardo, A., Capaccioni, F., Raymond, C. A., and Russell, C. T., 2013. Composition of the Rheasilvia basin, a window into Vesta’s interior. J Geophys Res-Planet 118, 335-346.

Melosh, H. J., Kendall, J., Bowling, T., Horgan, B., Lucey, P. G., and Taylor, G. J., 2014. The Moon`s upper mantle: Mostly Opx, Not Olivine? 45th Lunar and Planetary Science Conference.

Spudis, P. D., Martin, D. J. P., and Kramer, G., 2014. Geology and composition of the Orientale basin impact melt sheet. Journal of Geophysical Research: Planets 119, 1-11.

Wieczorek, M. A., Jolliff, B. L., Khan, A., Pritchard, M. E., Weiss, B. P., Williams, J. G., Hood, L. L., Righter, K., Neal, C. R., Shearer, C. K., McCallum, I. S., Tompkins, S., Hawke, B. R., Peterson, C., Gillis, J. J., and Bussey, B., 2006. The constitution and structure of the lunar interior. Rev Mineral Geochem 60, 221-364.

Deus Dominus Machina

By Thomas

Let’s do something totally unproductive today: Let`s play god.

Well, it`s going to be “playing god” if you go with the saying “Evolution is god’s way of issuing upgrades”.

For everyone else it’s going to be “Let`s play simple-laws-that-lead-to-complex-life”*.

A while back I read Richard Dawkins “The Selfish Gene” (1976) which argues that genes are the basic unit that natural selection is working on. I found the book was entertaining and it was easy to follow the arguments (even for laymen on the subject, like me). It replaced “The Science of Discworld” (Pratchett, Stewart, Cohen; 1999) as my Nr.1 popular science book. Naturally I went on reading more of Dawkins books and currently I am reading “The Blind Watchmaker”.

Fractal-Dragon-IFS-01Fig. 1: Fractal – Repetion of simple structures create a complex structure. From fractalsciencekit.

In one chapter Dawkins describes a small computer program to illustrate how evolution works. The basic principle that is used is the one of drawing a tree by using a simple algorithm. If you ever had the slightest contact with programming you`ll probably heard of that. If not you can see the basic principal here. This kind of algorithm is often used to show that complex things can arise from applying simple rules (see Fig. 1). In this case the simple rules are:

Draw a line.
After a while, split it into 2 (or 3, or 4, or 5 …) branches.
Then repeat that game with every branch.

The program in the “The Blind Watchmaker” takes the whole thing a step further:

It treads the variables in the program (e.g. “How many branches?”, “What is the angle between the branches?”, “After what distance does branching occur?”, “How often does branching occur?”) like genes that can randomly vary in their value. It also adds some more “genes” to allow for some more shapes to arise then tree-like ones. In the book the resulting figures are called Biomorphs. The program starts with a Biomorph and by randomly changing one of its variables/genes it creates “children” of this Biomorph.

And then comes the “playing god” part:
The program offers 8 children (with different variations in their “genes”) to the user and the user decides which one will be the “parent” of the next generation. Apparently it was possible to create quite complex structures using this simple program (Fig. 2). As I wanted to try the program myself I checked Google and found that there are several websites having some version of this program. Unfortunately most of them seem to be written centuries ago (meaning: in the 1990s) in a JAVA code that nowadays is mostly blocked or crashes browsers**.

Anyway, I found two versions that seem to work quite well:

1.) A pretty basic version, as far as I can tell similar to the original one described in the book.

2.) A version that seems a bit more complex and has COLOURS.

Fig. 2: Biomorphs from “The Blind Watchmaker”.

The middle square in both programs contains the “parent” which is surrounded by its “children”. To progress select one and it will become the new “parent”. You can just randomly select children to see what various forms some simple rules can create or you can put some selection pressure on the Biomorphs: Aim for a particular property (e.g. elongated, round, complex or a colour in the second program). The effect that is illustrated is breeding (evolution by selection by humans) but if you change the perspective a bit it serves as well to illustrate evolution by natural selection: Those biomorphs just “live” in an environment where it`s crucial for survival to be as colourful and as shaped as you want them to be.

Happy Evolving.

And don`t try to think too much about the possibility that we all just might be result of a slightly more complex Biomorph program – run by a procrastinating, 666-dimensional PhD-student.


*    Even though more likely to be true, this is just not such a catchy phrase as the whole Let`s-play-god-thing.

**   You could say those programs are not fit to survive in the modern day internet – it is JAVAlution.

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