The Right Turn

With a novel ring laser, LMU geoscientists can measure the rotational movements of the earth far more precisely and in more detail than hitherto possible. This week, the plant in Fürstenfeldbruck is officially inaugurated.

Up to now, the scientific community has not seen the town of Fürstenfeldbruck, some 20 kilometers west of Munich, as a hotspot. But now, geoscientists from LMU and the Technische Universität München (TUM) have commissioned a facility that sets scientifically clear standards. Between fields and meadows, they have sunk a hundred cubic meters of precision equipment, which is designed to measure the rotational movements of the soil as precisely as any other machine can do so far.

The design even brings the editors of the highly regarded but otherwise rather sober subject sheet Science into rapture. The novel ring laser, according to a news feature of Wissenschaftsmagazin, is the "world's most refined" device of its kind . ROMY(Rotational Motions in Seismology) is the project, scientific director is Heiner Igel , professor of seismology at LMU. For his work and the ROMY concept, the European Research Council (ERC) had awarded one of the coveted and highly doped grants, and the university still stuck up the budget. Meanwhile, the first experiments have taken place, on Friday of this week the plant is officially inaugurated.

Anything but a perfect ball
ring laser are sensitive rotation sensors, with which the rotation of the earth can be precisely measured. The planet is constantly moving; He walks around the sun and turns around his own axis. But this course is not always the same, it shows minimal deviations. A little like the earth, the axis fluctuates slightly, the drive is not constant. Strong winds in the atmosphere and the ocean currents drag on the globe, earthquakes shake it through. In any case, the earth is anything but a perfect sphere, because everything is not running smoothly.

To be able to accurately determine the minimum differences in the earth's motion - this is not an academic question. For example, each GPS system only works successfully if such deviations are incorporated into the position determination. The current method for this is the so-called long-base interferometry (VLBI), in which a global network of radiotelescopes quasars in the depths of the universe, millions of light years away. However, it is complex and delivers results only by days delayed. The Munich ring laser, the scientists hope, could turn out to be at least as accurate, but much faster. The measurement results should be available in seconds.

However, the LMU seismologist Hedgehog wants to push the new high-end measuring device into a new dimension and to analyze ground movements more precisely. For when a tremor shakes the earth, the ground moves not only up and down and back and forth. There are, for example, tilting and rotational movements, in which a certain point in space does not change its location. These are movements which the seismologists have so far neglected. Neglected, because, according to Igel, there were no possibilities to determine them with conventional devices. But in order to get a complete and realistic picture of the earthmoving, they are of relevance, unlike a long time, Igel believes.