Posts uit 2013 weergeven

Creating a network and find out the name of a rock!

At the end of a week full of science, I had a touristic trip into the woodlands of Muir. Together with a geologist I met in San Francisco, I traveled to the forest with the large trees seen in the very famous bike chase scene in Star Wars on the second moon of Endor. It was a great trip and I can recommend it to anybody visiting the City of Fog.
The Muir Woods are situated in a valley, where the climate is much different than the surrounding mountain lands. So a geologist and a geophysicist could not resist to climb a mountain to the top (I say mountain, but they were large hills, except when I said that the giftshop woman gave me angry eyes). We decided to follow the Hillside trail, followed by the Ben Johnson trail. These trails gave us a good view of the forest and let us examine some really nice rock outcrops of the mountain. And on one of them I found this rock:

It is a greenish rock, which according to the geologist, could be serpentinite or an olivine containing rock (which I …

Attending a talk of one of my scientific inspirations

It all started with a delay of four hours. Being on our route for over an hour (above Scotland), the intercom of the airplane (a MD11 type of aircraft) sounded: "This is your captain speaking and I have some bad news." There was a technical problem that could not be fixed in San Francisco, so it was decided to fly back to the airport Schiphol, Amsterdam. I was just finishing my first beverage. One of my colleagues told me that he had several experiences like this with MD11 aircrafts. They are old and should be taken out of service. But for now we got a different MD11 that would take us to San Francisco. Four hours later than originally planned, we arrived in the Fog City (it was a clear day). However, at the gate after the pilot had shut down the engines, the ground personnel tried to connect the power cables such that the doors could be open. Only this was not working, so 350 already a bit weary passengers were stuck inside the aircraft. And no power means no air-condition…

Delfi-n3Xt baby sounds...

This morning I got up earlier today to attend the Delfi-n3Xt launch event in our faculty. Delfi-n3Xt is a nano-satellite (the size of a milk carton) which is built by students and staff of our faculty. Launch events are always exciting, because you don't know what will happen. But after two stressful hours we got the confirmation, "Nano-sat number 7 successfully deployed." This was followed by some cheerful cheers. However, was it turned on?
This blog started with some post about listening to satellites using the ground station on top of EWI (faculty of electronic engineering, mathematics and computer sciences). This ground station is mostly set up by a student which I assist in teaching him to track satellites. So this gives me the opportunity to get the telemetry data of the Delfi-n3Xt quite fast. It's good to be a teacher :). The next figure will show the satellite's first sounds in space:

Click on the figure to get a larger view. In the bottom left corner of…

The Earth rotates (except in Copenhagen)

Last week, I was visiting the beautiful capital of Denmark, Copenhagen. I was selected to participate in the International PhD Elite Course "Tectonics" at the University of Copenhagen (READY program), organized by Prof. Hans Thybo and Prof. Irina Artemieva. During this five day course, the participants (PhD students from all over the world and me :) ) were being taught by two experts in the field of tectonics, the wonders of geosciences. From Geology (I write Geology, because it was defined by the lecturer as one of the two only real sciences); Prof. Çelal Şengör from Turkey with a beautiful British-sounding way of lecturing. From Geophysics (capital G, because I disagree with Prof. Şengör ;)); Prof. Seth Stein from the USA, who also brought his wive, Carol Stein. She gave a very interesting view on the Mid-Continental Rift. These last five days were fantastic, because I learned a lot and met numerous interesting people. I recommend any PhD student participating in such a c…

Secrets of the deep ocean (a Vening Meinesz story)

No, this is not a blog about some random Sci-Fi movie, it really is a blog about the secrets of the deep ocean (sorry guys, no shiny sphere that gives you special powers when you touch it). Already as a kid I was fascinated about large structures in the deep depths of our oceans. I will show you some cool geological features and their origin in the deep depths of the South Atlantic Ocean. Fortunately, Vening Meinesz, the geophysicist I am talking about now for some time, sailed over this huge ocean onboard the K18 submarine (yes, yes, I know, again I am spamming you guys about this very interesting and cool scientist). 
After visited several ports along the eastern South American coastlines, the K18 and its occupants started from Mar del Plata the difficult crossing of the South Atlantic Ocean. Vening Meinesz wrote in Volume III of his "Gravity Expeditions at Sea", the following about this crossing:
The crossing of the Atlantic from Mar del Plata to Cape Town was a strenuous…

Measuring the geoid. What is the geoid?

During my weekly fitness session with one of my friends, we started discussing gravity (yes, also my friends are geeks (in the good way)). We discussed the measurements done by Vening Meinesz in the K18. He used I pendulum device, that directly measures the downward gravity attraction in the location of the device, plus all the motions of the device itself. On land, these motion are negligible, but on sea the device swings a lot due the ocean waves. Therefore, Vening Meinesz used a submarine to reduce the motions of the measurement device (waves are dampened underwater). Furthermore, he used three pendulums instead of one, which he ingeniously used to separate the motions of the device and the gravity attraction. Explaining this all to my friend, he remarked that it sounded very complicated and asked me if this could be done more easy. "Yes, this is possible", I replied, "with a GPS receiver". "How is it possible to measure Earth's gravity field with a GP…

Writing is editing, rewriting and reviewing

Today I am working at home, because some strong and skillful looking men are renovating my roof vault (in Dutch: "dakkapel"). Luckily I had one thing on my agenda, editing, editing and editing. I have to rewrite my first scientific paper, because I want to send it to my co-authors in the beginning of next month. So today it is about making order in all my chaotic brain waves and scribbles, during the loud noise from above.
The title of this blog post is my way of living for the last few weeks (oh and "be concise and focus", but that is another story). I've started a course in English article writing, because as you would have noticed (and some of my good friends commented), my writing is not perfect or even close to perfect. So, every wednesday, I am sitting in a classroom with 12 of my peers, learning about the wonders of the English writing process. One of the most important lessons is: "Writing is editing, rewriting and reviewing".
But what is the…

Regional Isostasy: supporting a volcano

Since my participation in the Vening Meinesz project (Read about it in some of my earlier posts), I am reading a lot about this interesting person and his scientific findings. One of his greatest achievements to science is the theory of "Vening Meinesz isostasy" or "regional isostasy". This is a model that I use in my research and it is quite powerful but greatly overlooked. Therefore I thought it would be a good thing to write about here on my blog.
The word isostasy, I would think, is not something you would use in a normal conversation. However, you are reading the blog of a scientific geek (Aren't all geeks scientific, hmmmm), so now you will.
It all started with a man taking a bath. This man was given the assignment to solve a problem for his king. The assignment was to find out if the new crown of the king was made of pure gold. The king suspected the goldsmith of using silver. Archimedes (the man) was asked to do this without melting it. A difficult que…

Testing the theory of evolution: The story of the Red Dots

"But you are a geophysicist, not I biologist", I hear you thinking. Yes, that is true, but that does not stop me from looking at science in other fields. I think the theory of evolution is a great way to describe all the diversity we see around us. Not only in animals and plants, but also in man-made objects, politics, design, law, ethics and social interaction. Lets say evolution really is correct and is happening around us (I know that on the internet there is a large debate about its correctness, but I think one side just lack in good arguments and evidence), could we test it? To see if it really works.
Let me explain what I think evolution is about, correct me if you think I am wrong (finally some comments :)). Evolution in systems is about finding the optimal solution for the system to be in. Evolution does not know that it is doing this. The optimal solution changes over time, because of internal and external forces. In this sense evolution is very powerful. It allows…

Holiday project: my RaspberryPi shows that plants move!

After a few weeks of silence on this blog, a new post. Not about cucumbers, but moving plants (Do plants move? Yes, they do. Just very very slowly).
I bought a RaspberryPi before the holiday and wanted to test its capabilities and see how easy it was to program on it. So, I needed a project. After a view days of thinking I came up with making a time lapse movie (Ok, I know, not the most creative idea, but it was an idea). People might think that I would make a time lapse of the night sky, but I didn't. I am living in Delft, which is next to the Westland. This is a region with the largest surface area of the Netherlands (maybe even the world, I don't know, but you can see it from space, unlike the Great Wall of China) covered with greenhouses. At night they all turn on the lights. This makes it quite difficult to get a good view on the stars and Milky Way. So, I decided to capture other slow moving objects. Plants!!!
Another holiday project of mine is to grow my own fresh herb…

Two historical voyages crossing paths

In one of my previous post, I explained that I am currently working in a project to explain the measurements done by Vening Meinesz, a Dutch civil engineer responsible for high-accurate gravity measurements onboard the Hr. Ms. K18 submarine. He, together with the crew, sailed from Den Helder, Holland to Java, Indonesia. Stopping at harbors along the African, South American and West Australian coast.
At the end of december 1934, the Hr. Ms. K18 left port of Saint Vincent, one of the northern islands of Cape Verde. Cape Verde was also visited by the famous biologist Darwin during his voyage on the HMS Beagle. During this 5 year long voyage Darwin collected many observations that enabled him to establish the evolution theory. A theory that describes the diversity of living creatures and their way of adapting different environments, quite well, if I may say so. 
However this was many years before Vening Meinesz sailed from Saint Vincent. They sailed southwest to the center of the Atlanti…

Melting of the ice, backwards

A few days ago, two workmen were fixing my sewer and plumbing system underneath my house (It was kinda smelly). During the coffee break (which is the theme in my blog, all good things come from a coffee break), I had to explain what I did at the university. So I explained that I was looking at the motion of the Earth's crust due to ice loading during the late-Pleistocene ice age (well not in those words, and I did not mention, that I was doing this with satellite data, because my experience tells me to leave this part out. If you use the word satellites, people just stop listening and laugh). They found it very interesting ;).
I know, it is an abstract subject and difficult to grasp (it took me several months to fully understand the complexity of the problem, I am still working on how to solve it). Last week I needed to look at the ice sheet, that caused the motion of the crust that we observe today. People have made models on the growing and melting of this ice sheet, using all …

Do it yourself physics: Determining the curvature of the Earth, if you have better equipment

Working on this new project, see previous post, made me enthusiastic to do some gravity experimentation myself. I wanted to see if I can measure the curvature of the gravity field of Earth myself. I only needed a gravimeter (fancy word for very precise accelerometer).
Me, being a 'not-paid-much-just-enough' PhD researcher, I can not buy a very precise gravimeter, but I do have a laptop which contains three accelerometers to protect my harddisk in case of a joint meeting of the laptop and the ground. I wanted to see if I could use these for my little experiment (instead of going on an 8 month dedicated submarine voyage with state-of-the-art instruments, hmmmm, what was I thinking).
My laptop is a Macbook Pro (ok, don't start the discussion about which operating system is better. In the end it is all about the person using it) and I found the following code to (pretty easy) access the accelerometer data. The website for reading the accelerometer data gives a nice and clean …

A submarine voyage into the gravity field of Earth

Plate tectonics is a theory that is only 60 years old. Before this time, people were seeing Earth as a solid un-deformable piece of rock. Imaging you being a geophysicist in those days (ok, if you are currently not a geophysicist this is even more difficult, but in comparison try to explain the wonders of the internet to your grandparents.), having trouble to explain most of the things that where observed.
In those times a civil engineer, educated in Delft (my university :) ), went on a submarine voyage, measuring the gravity field of Earth. Wow, they should make a movie about this (I think they even did)! With his own designed pendulum equipment, the Dutch engineer could measure the gravity field with an accuracy up to a few mGal (which is very impressive, just trust me). Who is this brave, 2 meter tall (which I like because I am the same height), submarine-sailing hero? Born on 30 July 1887 in The Hague, he was named Felix Andries Vening Meinesz.
I am currently working in a project…

Destroying one of my childhood's fascinations

This week I received a package from the USA, containing my own Crookes radiometer (only a few bucks at (Yes, I am a geek, but the good well developed kind ;) )). This device is a small mill with black and white vanes in a vacuum pumped light bulb which turns around when you put it in sunlight (any light works!). It looks like this (pictures speak a thousand words, well in my case a few dozen)

My physics teacher used this device to explain that light particles have momentum (he should have known better), and due to the different reaction with the white and black colored vanes, the mill would turn. During my whole life, I was really sure about that this explanation was the effect causing the light-mill in vacuum to turn. Until this week.
My old master supervisor (not that he is old, but I am no longer a master student, he is my colleague now) entered my office room with a cup of coffee (this is of course essential for the story) and saw the Crookes radiometer. After making a…

Trying to figure out spacetime bending

A few years ago I was obsessed about Einstein's theory of gravity. I wanted to know everything about it, so I browsed a lot on the internet, trying to find information about the topic (I could have gone to the library, however I was still in the frame of mind that everything on the internet is correct). So one day I came across the following website: Bending Spacetime in the Basement. Wow, can one do this at home?!?
First take a good look at the website. He's got a point by stating that he is bending spacetime. It unfortunately has nothing to do with warp-drives and wormholes (Which was what I was looking for), but his experiment is quite cool nonetheless. It somehow proves (I will discuss this later on) that the theory of gravitation found by Newton, not only works for planet and stars, but also for smaller everyday objects. Everything attracts each other.
Impressed by the simplicity of the experiment and the fact that it is about gravitation (I think this is one of the most…

Did Scrat just trip?

This weekend we watched the fourth part of the Ice Age movies, called Continental Drift. Scrat the squirrel, always finding a spot to bury his beloved acorn, breaks a mountain and falls into the core of Earth. Arrived at a very small and solid core, he accidentally rotates the core, causing old continents to break up and drift appar, forming the current continents (Australia, Antarctica, Africa, Europe, South America and Asia. North America is formed at the end of the movie, where Scrat pulls the plug of Scratlantis (Yes, again Atlantis, it just must exist), forming North America.). A really funny scene and it gave me inspiration for this post. This weekend I was struggling to think about a blog subject. Thanks to Scrat, I found my acorn: Continental Drift.

In my research I work with topography, gravity and seismic observations. I am trying to combine all these observations in a new way, such that I get better insight of the old continental structure under Scandinavia, Finland and nor…