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Losing a friend you did not know you had.

Monsters are real, and ghosts are real too. They live inside us, and sometimes, they win. ~ Stephen King

There are words that do not come easily. Yesterday the world has lost a great person. The actor Robin Williams died.

You may have seen his funny movies. You may know him as Peter Pan. (Bangarang, Robin!) or as ever-inspiring teacher of the club of dead poets. Maybe the clown who cares about terminal patients has gotten to you. He was the funny guy. I once saw him do a stand-up-like performance about playing Call of Duty, it was hilarious. He knew how to draw in his audience. Maybe you know his more serious roles from Good Will Hunting. It really doesn’t matter.

You see this person. You see he has everything. He is funny, has a family, friends, wealth, fame, inspiration. And he has depression. Imagine how many people have told him to “get over it”. “You’ve got everything, what more do you want?” “Just try some Yoga, no one can feel bad doing Yoga!” Unfortunately it’s not about what you have. Depression is the state you’re in when you perfectly know what to do but can’t. It’s the state where your body just says “Nope!” and you’re overwhelmed. It’s the state when the demons in your head break through and whisper terrible things.

You may or may not know these demons. Everyone has their own ones. They tell you you’re ugly, lonely, unloved, unwanted and a bother. It’s fine to be ugly, unloved unwanted but what’s for the worst is being a bother. All the people trying to help you, but no one can really do anything to help. No smart hint or Jedi mind trick has yet helped. The only thing that will lead you out the other side is a friend saying “Don’t worry I know what it’s like, I’ll just be waiting here and I’m still your friend. You’re not alone.”

Today Robin Williams, a great inspiration and a friend who would help you through a tight spot with his movies and his humor, listened to his demons and decided not to bother anyone anymore. In his mind it was a service to us, in my mind it will be a great loss.

I don’t know if anyone else liked him, but losing someone this famous to depression will have consequences. Be there for someone who is facing this struggle, this is not a good time. Tell them their demons are lying and that you’ll still be there when they get out of their bed. I know a lot of people will need that now.

The last curtain falls.
May you find Neverland.

Gain traction in the Geoscience community

The internet is a wonderful place. I am one of the lucky people who does not have to wait for weeks to get a hold of a paper I might need for my thesis. As a scientist this international network has become indispensible. Not just for retrieving papers, but also the review process and colaboration. The committee I doing my thesis on subsalt imaging with is situated in Germany and the Americas and has sponsors from all around the world. These kinds of collaborations spur scientific progress.

An Update on RSS

Of course this is not it. In my first post on geo-awesomeness I gathered up resources and ways to get the latest information in the laziest way possible. You know, because I’m that type of guy. I’d rather have my infomation curated in one place than habitually check the SEG, EAGE, SEP, AAPG (I think you get the point) for updates in their catalogue. I also love the blogosphere of geoscientists. Getting input from all these intelligent people has advanced my own understanding quite a bit as well as tied some good connections. So naturally, I included a lot of these blogs in my daily routine of reading as well. As I understand that some people, like me, would love to do it that way, I bundled an OPML with all these resources. You can get it here.

Nowadays since Google Reeader has eventually closed down, my favorite reader (Feedly), has evolved quite a bit. Adding this xml file hast become even easier. On the left bar you can find a link to Add Content which will open a selection of options. There you can just choose Import OPML and read all the latest news.

Accretionary Wedge

But I did not start this post to talk about good ol’ RSS. The Geocommunity has evolved quite a bit in the past. Bloggers and scientist are interconnected. There is a monthly blog-carnival called the Accrectionary Wedge, where any bloggers can just contribute stories to a common topic.


Twitter is the Go-To place to get to know the awesome people behind those blogs as well as more other scientists. They’re a warm and welcoming group, appreciating anyone willing to chime in. Seriously, get on there and Tweet, Retweet and just start talking to people. You have a 140 character limit, which forces you to be on spot with what you’re saying. Any geophysicist knows about signal-to-noise ratios and Twitter has a quite unique system for this. You can “Retweet” anything you like, either with the native retweet button or by qoting the original tweet preceeded by a “RT”. If you change the text of the original tweet be sure to use “MT” instead. Giving credit is just like citing a paper in the world of Twitter. Personally, I also like to credit a person, I learned something awesome from using a “h/t”, which signifies “heard through”. So head over to Twitter and follow me and some other awesome people. You can also reach me through

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Cloud Chambers

At the moment I am working on my Master’s thesis. As this is taking up a lot of my resources, I fail at generating more content for this blog. Geophysics related writing goes into the thesis right now. However, I’ve written a short piece on visualizing radioaktive decay in a diffusion cloud chamber. It’s not geo-content but interesting nonetheless. (The references are all to Wikipedia, just for further reading, so barely sources - if at all.)

The Cloud Chamber1

The chamber itself contains vapor, we use Isopropyl alcohol for this. The entire chamber is filled with this air-vapor mix, like a bathroom is filled with water vapor after a nice hot shower. On the bottom of this cloud chamber we have plate that is cooled down to -30°C (-22°F). The surface is very smooth to reduce the possibility of condensation.

Since we have heating at the top and cooling at the bottom we get a vertical temperature gradient. About 0,5cm (0,2in) above the cool plate the vapor isn’t quite ready to condensate and gets supersaturated. This basically means the partial pressure of the vapor is higher than its vapor pressure2. So that layer above the plate contains more alcohol than it should. However, it won’t condensate because we’re missing an important part: condensation core (or nuclei)3. So basically something that will trigger the condensation.


Alpha decay
Alpha decay
And this is where radioactivity comes in handy. We have different kinds of radioactive decay, two of those can be seen in a cloud chamber. Namely it’s alpha5 and beta decay6. Those emit charged particles. Alpha decays emit a Helium nucleus, those have pretty high energy but short range. Beta decay either emit an electron or a positron. They’re usually less energetic but have much higher range. The radioactive gas, we blow into the cloud chamber is Radon. Radon is one of the gases that contribute to natural background radiation7.
Beta decay
Beta decay
However it’s not really easy to store, so we use a trick. Radioactive isotopes will decay in certain patterns from one isotope to another, this is called a decay chain8. Since we want to utilize a certain decay (we’ll come back to this later), we can now see which solid isotope is suitable for our purpose. In our case it’s Thorium:

228Thorium -> 224Radium -> 220Radon -> 216Polonium -> 212Lead

We can see that at some point Thorium decays indirectly to Radon, our desired gas. We blow this into our cloud chamber and enjoy the radioactive magic. 220Radon does an alpha decay and emits a Helium nucleus, so it’s 216Polonium now. This special kind of Polonium is very unstable and has a half life of 0,15 seconds. When we stand 50 meters (165ft) apart, this is the time it would take for you to hear me yell something9. In our perception that is almost immediately. Polonium also emits a Helium nucleus, so this is the reason we see two big lines happen almost at once. Of course, if you’re very observant, you will see some of the lines clearly happening after one another. This goes a little deeper into radioactive decays. As radioactive decay happens randomly, the 0,15s half life just gives a mean time10, when half of the polonium will decay, the other half will probably take longer. (This is where statistics come into play and I’ll just leave it at that.)


Impact Ionization
Impact Ionization
This isn’t quite it, but up to this point we’re done with the radioactive decay. We understand that there are two alpha decays that happen almost immediately. Both emit a Helium nucleus, but why would this nucleus cause a glowing line in the supersaturated vapor? The supersaturated vapor is in a so-called metastable state. It would condensate if it had a condensation nucleus. This is where the high energy Helium nucleus comes in. On impact with other particles this high energy particle will ionize other particles around. In this process alcohol particles become charged and can therefore serve as a condensation nucleus. This ionization charges particles by kicking electrons out of the alcohol molecule. These electrons will then ionize other alcohol particles, like an avalanche. Hence, causing the trace of condensed vapor. The Helium nucleus itself would only have a maximum range12 of 3-4 cm (1.6 – 1.8 in) in free air but the trace is at least twice as long.

Bragg Curve for Alphas
Bragg Curve for Alphas Source

The traces itself are visible because the little droplets in the fog cause Mie scattering13 of the light. This is the so-called Tyndall effect14 that causes light to be radiated outwards of fog and clouds.

Tyndall effect in different media
Tyndall effect in different media
(Tea, colloidal silver, water)
CC-by-sa 3.0/de Pies und Braach

After every “glowing trace” we can see a black trace, which is due to the temporary absence of the supersaturated vapor after condensation.

Here’s an image of our chamber at DeSy on Wikipedia