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Astronaut lost in space

and other odd problems for nerdy engineers are contributions by SDU Mechatronics to the famous and highly respected back page of Ingeniøren.

The Danish magazine Ingeniøren is a weekly magazine targeting mainly engineers and scientists, but also students and teachers - in fact anyone interested in science and technology. The back page of Ingeniøren is famous and highly respected for its oblique and humorous approach to any strange topic that can be exposed to investigation, often initiated by its readers. In 2018, Ingeniøren reached out to universities asking them if they were willing to provide odd/alternative/funny/strange problems, nerdy enough to qualify for the back page! Since then, the Mechatronics Section at SDU has been the most frequent supplier of such problems.

- The ideal ‘back page problem’ should be phrased in a few sentences and any reader should immediately be able to grasp what the problem is about, says associate professor Bjarne Schmidt who has provided many of the problems in the past years.

- However, the solution should not be straight forward. At  best, the readers' first thought should be that there is not enough information provided!

It is not the intention that the solution should require very specialised knowledge - an open mind, a creative approach and, from time to time, some mathematics skills should do the work. The readers are given the opportunity to discuss their ideas and solutions in a discussion forum on the magazine’s webpage, and usually a lot of stimulating debate is going on there. The solution is published in the following issue of Ingeniøren.

An example of such a problem deals with an astronaut lost somewhere in our solar system. With a folding ruler (with known mass) as his only measuring tool and a piece of string with known torsional constant, the reader should be able to determine what planet the astronaut is visiting.

- It is not always easy to come up with a good idea for such problems, Bjarne Schmidt says. You cannot force such ideas to pop up. Sometimes the inspiration comes when teaching my classes, sometimes from reading a scientific paper or when shopping groceries in the local supermarket. For instance, I just finished a problem that I was inspired to when cooking tomato soup at home. It will probably be published in Ingeniøren in a couple of months. Hopefully, the problem will initiate a lot of good discussions on the webpage too, Bjarne Schmidt concludes with a grin.


The Danish magazine Ingeniøren appears in print every Friday and its official number of readers is close to 150.000. It can also be read online on
Editing was completed: 29.01.2020