By Simon Redfern, University of Cambridge

How is it that Earth developed an atmosphere that made the development of life possible? A study published in the journal Nature Geoscience links the origins of Earth’s nitrogen-rich atmosphere to the same tectonic forces that drive mountain-building and volcanism on our planet. It goes some way to explaining why, compared to our nearest neighbors, Venus and Mars, Earth’s air is richer in nitrogen.

By Ingrid Sharp, University of Leeds

The idea of a war hero is still strong in the UK and in the other Allied countries.

War memorials are a central feature of the regular commemoration services, Churchill is regularly rolled out in biographical and fictional form, and there are soon to be a total of 888,246 ceramic poppies for 888,246 war heroes adorning the Tower of London.

By Clifford Murphy, University of Maryland, Baltimore County

By Don Brushett

It’s hard to get a bad coffee these days.

Plenty of baristas have fine-tuned the process of making espresso, but really there are only a handful of variables they can control:

By Catherine Womack, Bridgewater State University

Taking care of sick people has always involved personal risk.

From plague to tuberculosis to smallpox to SARS, health-care workers have put themselves in danger in the course of fulfilling their duties to care for others. Many have lost their lives doing just that.

By Pep Canadell, CSIRO

Through burning fossil fuels, humans are rapidly driving up levels of carbon dioxide in the atmosphere, which in turn is raising global temperatures.