Analysis of wastewater from sewage systems has provided an early warning system for the presence of Covid19 in communities – showing up in the water samples before people test positive. It’s also possible to identify the variants and even specific genetic mutations. Davida Smyth of Texas A&M University has been using this technique in New York and found intriguing results -forms of the virus not present in humans. The suggestion is that mutated forms may be infecting other animals, possibly those present in the sewers. An analysis of long Covid, symptoms of fatigue, and ‘brain fog’ which occur long after initial infection, show that around a quarter of those infected develop these symptoms. Lucy Cheke of Cambridge University discusses the implications.

The war in Ukraine has highlighted the importance of the region in supplying raw materials and energy to other countries, gas, cereal crops, and fertilisers in particular. As crop scientist John Hammond from Reading University explains stopping of fertiliser exports from Russia, in particular, could impact food security in many countries.

And with unseasonal fires already burning in the Western US Caroline Juang of Columbia University’s Earth Observatory gives us her analysis of the driving factors in the intensification of fires year on year.

Faced with one cake and eight hungry people, it’s pretty obvious how maths underpins reality. But as mathematics gets further from common sense and into seemingly abstract territory, nature still seems to obey its rules - whether in the orbit of a planet, the number of petals on a flower, or the structure of an atom.

But what exactly is the relationship between mathematics and reality? That’s the impossibly difficult question CrowdScience has been set this week by our listener Sergio in Peru. It’s one that’s been pondered by humans for millennia: the Greek philosopher Pythagoras believed “All is number”.

Is maths a human construct to help us make sense of reality - a tool, a model, a language? Does maths create its own reality? Or is it reality itself?

(Image: USA, New York, steam coming out from sewer. Credit: Westend61 via Getty Images)