Category Archives: Science & Technology

The Special Theory of Relativity, Part 2 – Mass, Energy & Space / Time – Richard Jones

Richard’s presentation on Special Relativity Part 2 began where Part 1 ended, looking at the experience of a person travelling at relativistic speeds. The visual effects are aberration of light from stars around a spacecraft, the Doppler shift and the so-called searchlight effect. The twin paradox of unequal ageing of travellers was briefly mentioned but this is properly in the domain of General Relativity. Continue reading The Special Theory of Relativity, Part 2 – Mass, Energy & Space / Time – Richard Jones


Is there life after industry? – Prof Michael Johnson

Prof Johnson had conducted a fundamental review of natural environmental services at the University of Liverpool in partnership with Merseyside County Council. He had held a lectureship at Liverpool, & had then been offered a chair at Imperial College, London. However, the Rio Tinto Company had endowed a personal chair for him at the University of Liverpool, following which he sometime later moved into the private sector as a consultant to the mining industry.

He had studied the estuaries & coastal waters, & particularly pollution of the Mersey Basin. High levels of toxic metals (Hg & Cu) had been found in the fish in these waters, with peak levels of Hg in ~ 1980 thru 2015. Discharge from local chemical industry was found to be the source of this pollution. There were also toxic organic pollutants (e.g. pesticides & PCBs) found in estuary fish. By comparison, the Dee estuary was much less polluted. Continue reading Is there life after industry? – Prof Michael Johnson


U3A Explores Science at the Ri

A couple of group members attended this interesting event. The presentations were:

  1. Prof. Ian Crawford (Birkbeck College) – “Where are the aliens?”
  2. Michael de Podesta (NPL) – “How do we know anything? And how can we know things better?”
  3. Catie Williams (UCL) – “Wild at heat but captive in gut: Exploring the effects of life in captivity on the gut microbiomes of re-released chimpanzees”

U3A TVN Study Day: “The Science of Food Production in a Changing World Climate”

A couple of group members attended this interesting study day.

The speakers were Dr. Martin Hodson (Oxford Brookes University) and Dr Mary Miller (AgriculturalGenetics, Cambridge).

The talks given were:

  1. What is happening to our climate? (MH)
  2. The effects of temperature & rainfall on agriculture. (MM)
  3. The carbon dioxide fertility effect: friend or foe? (MH)
  4. Can genetic engineering help in food production? (MM)

The Special Theory of Relativity, Part 1 – Time and Distance – Richard Jones

Einstein’s Special Theory of Relativity was presented to the world in 1905. It had its origins in Scottish physicist J Clerk Maxwell’s work on the propagation of light. From experimental laws of electricity and magnetism he used mathematics to derive a formula for the speed of light which made no mention of what that speed might be relative to.

Continue reading The Special Theory of Relativity, Part 1 – Time and Distance – Richard Jones


Biodiversity – Dr Martin Hodson

We were treated to an excellent talk, “Biodiversity”, given by the environmental biologist, Dr Martin Hodson, a lecturer and researcher at both Oxford Brookes and Oxford Universities. After detailing the history of the study of biodiversity, Martin gave details of the current number of identified species (1.2M) and said that it was believed that 86% of species had not yet been identified. The number and distribution of plants and therefore other living species varied depending on the habitat, with regions enjoying warmer wetter climates, such as tropical rain-forests, supporting the greatest variety of species. 17 countries contain 75% of the world’s biodiversity with hotspots in the Sunda Islands, the Philippines and Madagascar, all areas which are undergoing substantial man-made environmental change. Continue reading Biodiversity – Dr Martin Hodson


How radars work – Garth Wilkinson

Garth Wilkinson covered the history of the basic physics of the propagation of electromagnetic waves at the velocity of light as predicted by James Clerk Maxwell & experimentally verified by Heinrich Hertz. The nature of the electromagnetic spectrum was described, and the frequency bands normally used by radars were identified in relationship to atmospheric transmission windows. Continue reading How radars work – Garth Wilkinson