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Posts uit 2016 weergeven

The day the Earth changed its rotation-rate

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This week I saw a great article in Wired.com about the static test of one of the solid boosters for the SLS rocket. So I tweeted: "The Earth rotated a little bit faster that day! #rocketengine". I should have known that I cannot make these kind of statements without proving them first. One of my friends called my bluff.

So, I replied with "Challenge accepted!". The blog post will report on my investigation and show how much the Earth speed up/slowed down by the QM-2 test of the SLS booster rocket. My investigation consists of three parts: the model, the search for reliable information, and my conclusions.
Model of the Earth with an attached booster By igniting their propellant, rockets can produce thrust that normally propel them upwards towards space. If you fix them on the Earth they could speed up or slow done the rotation of the Earth, depending on  the direction of its thrust. Ok, hold your horses! Of course this will have a small effect, but I still need to s…

The gravimeter of professor Vening Meinesz

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On a cold winter day, 21 November 1934, professor Vening Meinesz turned on his pendulum apparatus. Just a few minutes ago, the submarine K-XVIII dived to a depth of 30 meters [1]. At these depths, the motion of the surface waves was dampened such that it did not influence the delicate measurements done by the professor. This particular observation would mark the 500th measurement, observing the tiniest changes in the Earth's gravity field. This new gravity dataset would reveal many new mysteries of our home planet and would be the life’s work of Vening Meinesz. It is all documented in scientific publications of four volumes called Gravity Expeditions at Sea, followed by a fifth volume with gravity observations done by his students. Along these expeditions, the professor had brought his specially designed pendulum apparatus, or folklorised by the sailors on board the many submarines: Het Gouden Kalf (the Golden Calf).
During the beginning of 1900, Earth's gravity field was only …

Hearing the sound of a satellite

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So, the last few weeks were quite exciting at the DopTrack satellite tracking station. We have updated the software, such that the station is now able to automatically record any satellite we tell it to record. Also, the radio antennas are installed higher in the sky for better visibility. Moreover, TUDelft students have designed software to automatically extract the carrier signal from raw recordings. And last but not least, the development of the website for the Virtual Laboratory DopTrack is started, but I will report on that later on, when we have a working website. All major steps to have our project become a real educational tool for satellite tracking. 
Software update: Automated satellite tracking The DopTrack station is now able to automatically compute, when a satellite is flying over and start recording it accordingly. We just have to set a line of code in the rec.list file and DopTrack is doing the rest. An example recording list is:
Delfi-C3                          32789 …