Abstracted/indexed

In this text we examine the historical and cultural context of the Great Comet of 1577 from the perspective of Chaim Vital, who recorded his observation of the comet on the evening of 10 November 1577. This observation includes a description of a possible aurora, by noting the presence of a chasm in the sky. This kind of description is common in Western medieval accounts. In his Book of Visions, Vital only noted the event without interpretation, likely due to comets being considered ill omens.

According to climate simulations, the Earth's atmosphere is warming up as a result of human emissions of greenhouse gases. But, a causality relationship between these emissions and temperatures has not been directly demonstrated. Over a period of 423 000 years, analyses of polar ice cores in fact show that CO₂ was not a cause, but an effect, of the the temperature changes recorded during cycles of glaciation–deglaciation. Hence, Milakovitch cycles are the only drivers of climate change.

This paper examines how ionospheric physics emerged as a research speciality in Britain, Germany, and the United States in the first 4 decades of the 20th century. It argues that the formation of this discipline can be viewed as the confluence of four deep-rooted traditions in which scientists and engineers transformed, from within, research areas connected to radio wave propagation and geomagnetism.