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For a long time, human beings have lived with the idea of cycles, as attested by many ancient traditions. This perception led our way of observing and interpreting the most diverse types of phenomena. In the Earth sciences, cyclicity has crucial epistemological value. It offers simple solutions for cause and consequence analysis in time and space. The intention here is to review how such ideas emerged in the geosciences, supporting current stratigraphic principles and practices.

The Commission on Tephrochronology (COT), formed in 1961, comprises geoscientists who characterize, map, and date tephra (volcanic ash) layers and use them as stratigraphic linking and dating tools in geological, palaeoenvironmental, and archaeological research. We review COT's origins and growth and show how its leadership and activities – hosting meetings, supporting ECRs, developing new analytical and dating methods, and publishing volumes – have strongly influenced tephrochronology globally.

EISCAT, the European Incoherent SCATter system, was an advanced research radar system established in northern Scandinavia in the mid-1970s for studies of the aurora and the earth's plasma environment. This paper describes the operation, development, problems and successes of the system during its first 2 decades, as recalled by its former deputy director.

In this article, I trace the history of the models of ice ages during the period between the nineteenth and twentieth century. Some previous versions of ice age models were briefly discussed. I present a bird’s-eye view of the scientific collaboration in developing a model and of the reasons behind the success of the Milankovitch model as well.

The paper compares the historical context, organization, personnel, conduct, and scientific innovation of the voyages of HMS Challenger (1872–6) and SMS Gazelle (1874–6). Though the expeditions were in many regards similar, the Challenger expedition became famous and is regarded as marking the start of global marine science, while the Gazelle voyage remains almost unknown. Why? A surprising factor may be what we now know as "health and safety" issues.

We present the history of how and why a high-power radio wave transmitter facility with large antenna arrays was built in northern Norway in the 1970s with the aim of injecting radio waves into the auroral ionosphere. The facility has conducted fundamental research on plasmas, by heating electrons and exciting plasma waves in the ionosphere; the effects of these experiments have been measured using a host of other instruments, such as incoherent scatter radars, radio receivers, and cameras.

The road to success for Danish seismologist Inge Lehmann (1888–1993) – known for her 1936 discovery of the Earth's inner core – was difficult and full of challenges. While she herself refused to accept any notion of gender difference ascribed, society at large was less open-minded. Using newly discovered, unpublished historical documents, this article examines to what degree her gender played a decisive role in her graduate and postgraduate experiences.

Lerwick Observatory in Shetland has recently celebrated its centenary. Measurements of atmospheric electricity were made at the site between 1925 and 1984. The instruments and equipment used for this are discussed and the value of the measurements obtained assessed. A major aspect of the atmospheric electricity work was explaining the dramatic changes which followed the nuclear weapons test period. Although less well known, there are strong parallels with the discovery of the ozone hole.

Kakioka Magnetic Observatory (KMO) has been monitoring the geomagnetic field and electric field at Kakioka, Japan, since 1913. It has promoted a variety of observations and research activities. In 1972, KMO developed the Kakioka Automatic Standard Magnetometer (KASMMER) system, which enabled them to provide geomagnetic field data of the highest quality. Today, KMO operates a network of observatories in Japan and maintains the observations with the longest history in East Asia.

The term mascon either refers to the fact of a significant gravity anomaly within a celestial body or to a modelling of these gravitational anomalies by localising base functions. The localising base functions that are labelled as mascons include point masses or surface elements based on the simple layer representation. In the case of surface elements, the surface density is constant per mascon, and each localising base function is a two-dimensional step function on the sphere.