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Medicine is placing high expectations on implants and auxiliary materials that are manufactured specifically for each individual patient. This can be done by means of additive manufacturing (3D printing), which allows nearly any complex shape to be produced. Before starting to use such implants widely, the medical sector and certification bodies demand proof of the fact that their high quality is matched and will remain stable over time. Within the scope of a European project, MetAMMI, PTB has provided the basis for the quality control of medical implants and auxiliary materials produced by additive manufacturing.

Walther Meißner, der Pionier der Tieftemperaturforschung, ist der Namenspatron des neuen Gebäudes, das die Physikalisch-Technische Bundesanstalt (PTB) auf ihrem historischen Gelände in Berlin-Charlottenburg bekommt. Es wird seit dem Jahr 2017 vom Bundesamt für Bauwesen und Raumordnung (BBR) errichtet. Jetzt naht die Fertigstellung des hochspezialisierten Wissenschaftsbaues, in dem es unter anderem um die Forschung rund um sogenannte SQUIDs gehen wird – eine Spezialität der PTB, bei der sie seit Jahrzehnten in der Forschung eine internationale Spitzenstellung einnimmt. Auch das „neue Kelvin“ bekommt hier gewissermaßen eine Heimat.

On 20 May 2019, World Metrology Day, the revised International System of Units (SI) entered into force. On 16 November 2018, the revision was adopted unanimously by the representatives of all member states of the Metre Convention at the 26th General Conference on Weights and Measures (CGPM) held in Versailles. Since 20 May 2019, all SI units are based on a set of 7 defining natural constants. Thus, the differentiation between base units and derived units de facto no longer applies. In everyday life and for any standard consumer, nothing has changed. The change is, however, relevant to precision metrology as well as to teachers who will no longer be able to tell their students the relatively simple story of the international prototype of the kilogram but will have to elucidate the far more complex universe of natural constants.

If you come across someone who can tell you by heart and without cheating what a kilogram is after 20 May 2019, beware! It is probably a particular kind of scientist, a metrologist, who is still overly enthusiastic about the fundamental change experienced by the International System of Units, the SI. From 20 May 2019 on (World Metrology Day 2019), things as abstract as natural constants will be the measure of all things when it comes to defining what exactly a kilogram, an ampere, a kelvin and a mole exactly are. After years of research at the major metrology institutes, and in particular at the Physikalisch-Technische Bundesanstalt (PTB), the world community eventually agreed upon this revision of the System of Units – a revision that comes into force as of on World metrology Day.

Schon als Jugendliche sind sie vom Forscherfieber gepackt: die TeilnehmerInnen von Jugend forscht, die ein wissenschaftliches Thema gründlich und nach denselben Vorgaben untersuchen, wie sie weltweit für sorgfältige Forschung gelten. Dies ist auch so bei der anschließenden Veröffentlichung in der Jungen Wissenschaft. Die Zeitschrift für ForscherInnen unter 23 Jahren ist eine Peer-review-Zeitschrift;die Artikel gelten als zitierfähig. In den letzten 30 Jahren war die Junge Wissenschaft ein gedrucktes Magazin. Die Physikalisch-Technische Bundesanstalt (PTB) hat aus ihr ein Online-Journal gemacht, eine nichtkommerzielle Open-access-Zeitschrift. Unter www.junge-wissenschaft.ptb.de sind zurzeit rund 180 Originalveröffentlichungen junger ForscherInnen zu finden – und es werden laufend mehr. Demnächst wird noch eine App speziell für Tablets und Smartphones folgen. Aktuell wird beim Bundeswettbewerb von Jugend forscht am 16. Mai die...

In his Special Theory of Relativity, Einstein formulated the hypothesis according to which the speed of light is always the same, no matter what the conditions are. It may, however, be possible that – according to theoretical models of quantum gravitation – this uniformity of space-time does not apply to particles. Physicists have now tested this hypothesis with a first long-term comparison of two optical ytterbium clocks at the Physikalisch-Technische Bundesanstalt (PTB). With these clocks, whose error amounts to only one second in ten billion years, it should be possible to measure even extremely small deviations of the movement of the electrons in ytterbium. But the scientists did not detect any change when the clocks were oriented differently in space. Due to this result, the current limit for testing the space-time symmetry by means of experiments has been drastically improved by a factor of 100. In addition to this, the extremely...

What can we expect from the revision of the International System of Units (SI), which was approved on 16 November 2018 and will enter into force on 20 May 2019? The answer depends on who you ask – an ordinary citizen, a student, a scientist or a metrologist in industry. The editorial staff of maßstäbe has asked this question – and gathered the answers in a new issue that is just as colorful and diverse as the answers obtained (Issue 14, “Maße für alle”, only in German). You can order this issue individually or as a classroom set free of charge; alternatively, you can subscribe to maßstäbe.

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On the occasion of their 26^th General Conference on Weights and Measures (CGPM) in November 2018 in Versailles, the signatory states of the Metre Convention decided to fundamentally reform the International System of Units (SI). This resolution stipulates that, in the future, all SI units will be based on the numerical values laid down for seven selected natural constants. In passing this resolution, the General Conference has followed a recommendation issued by the International Committee on Weights and Measures (Comité international des poids et mesures, CIPM) – the world's supreme expert committee on metrology. The new definitions of the units will come into force on 20 May 2019, World Metrology Day.

Die Deutsche Telekom hat angekündigt, den Anschluss des Telefonzeitdienstes der PTB, Rufnummer 0531 512038, Ende Februar 2019 auf IP-basierte Telefonie umzustellen. Die PTB empfiehlt, bestehende Systeme über eine zusätzlich geschaltete, IP-basierte Leitung zu testen.