Your letters.

This document is a collection of letters from readers of New Scientist magazine. The letters cover a range of topics, including ageism in banking and insurance, the ethical concerns of pig farming, offsetting carbon emissions from flying, the use of colored LED street lighting, the role of climate change in the collapse of civilizations, the theoretical models of cosmology, and the plausibility of alien megastructures. The letters provide diverse perspectives on these subjects and offer suggestions for alternative approaches. [Extracted from the article]