Letters archive

Kelly and Zach Weinersmith consider challenges to living on Mars. Fictional futures sometimes improve the Martian climate by moving the planet closer to the sun, but the more I learn, the less plausible these scenarios seem ( 16 November, p 48 ). Back-of-the-envelope calculations suggest that moving Mars into Earth's orbit would require energy equivalent …

I fear Mars would be a dreadful destination for colonising for all the reasons stated, plus the planet-wide dust storms that would kill any hope of photosynthesis for periods and interrupt solar power. And what about surviving the maddening isolation? At least on the ISS one can look out of the window at the beauty …

Reader Gerald Legg asks why the wreck of Ernest Shackleton's ship Endurance, found at the bottom of the Weddell Sea in Antarctica, looks so good ( Letters, 16 November ). There are several reasons. The cold water temperatures (-1.8°C; 28°F), total darkness, low oxygen and lack of sedimentation, together with the ship's strong wooden construction, …

Your article "The Botanic Age" gives welcome space to the subject of pre-Stone Age advances. It would seem important to also mention the Bamboo Age. Bamboo is nature's fast growing construction material and it can be modified to make anything from a knife to a source of ignition, cooking pot or twisted thread. It is …

As a hobby willow-basket maker, I have often observed that no tools are required. A sharp knife is useful, but not necessary. Likewise, textiles and grass-fibre baskets require no tools to create. The notion that early humans or prehumans waited for stone tools to be invented before developing other technologies is absurd. Our ancestors were …

Neither your article on the impact of food production on the planet nor the editorial that accompanied it mentions the health and maintenance of the largest biome bar the ocean: soil. It is unlikely that wheat yields could increase by 18 per cent by 2100 if farmers keep doing what they are doing unless you …

As a myope and optometrist, I find the term "disease" for myopia misleading. Axial length of the eye is a continuum; people whose eyes don't grow long enough have hypermetropia/long-sight. No one says this is a disease, but it also requires spectacle correction ( 16 November, p 40 ).

When it comes to myopia, there is a mystery that has long plagued me. After illness kept me at home for a few days, I returned to school to find I could no longer make out writing on the blackboard. A lifetime of spectacles and contact lenses to correct "short-sightedness" ensued. My mother always insisted …

Myopia isn't all bad news. Reading small print or seeing fine detail is easy even as an adult, when this acuity can otherwise fade. Perhaps an evolutionary advantage arose after fine craftsmanship became an essential survival skill.

For most of my life, my brain rendered the moon as a flat disc or crescent in the diamond-studded canvas of the night sky. However, I discovered that if I think of the moon as spherical while I look at it, it pops out that way. Instead of a flat object, I see it for …

On the issue of whether grief motivates a pet dog to bite the face of a dead owner, I have seen a few human bodies that have been partly eaten by animals. I suspect most target the face because it isn't clothed and there are easy routes to the soft interior, such as eyes, ears, …