Doomsday
Your article “Doomsday book” (7 January, p 38) is one of the very, very few critiques of our work, , which clearly states our goal was to understand the dynamics of growth in a finite world rather than simply to predict collapse or provide a litany of various limits to physical growth.
Humanity’s use of energy and materials is now so far above the globe’s long-term, sustainable capacity that collapse of some sort is inevitable. Thus I do not pay much attention these days to discussions about how one or another technology will “save” us. It is nevertheless very gratifying to see our message succinctly and accurately conveyed.
No future
In reviewing Brian Clegg’s book How to Build a Time Machine Manjit Kumar discusses the theoretical limitations of time travel (10 December 2011, p 52). Clegg ponders the absence of time-travelling guests at an event they were invited to in 2005; this may be a harbinger of our own fate.
We have developed unprecedented means of self-destruction, and maybe our species does not survive long enough to develop time travel technology. A sobering thought.
Scientists unite
In response to Paul Root Wolpe’s call for a unifying symbol to rally all scientists (7 January, p 24), my offering is a stylised question mark, where the hook part looks like a light bulb, and the full stop has been made to look like the screw fitting of the bulb.
I believe this is general enough to encompass all domains, the idea that as scientists we all “question”, but every now and again we have a eureka moment where “the light does indeed come on”.
From Steve Skinner
I could not agree more with Wolpe. He states that a logo for science should be simple and versatile, instantly recognisable, encompass all disciplines and be able to incorporate additions – for example, a double helix, an atom, or the word NASA.
My idea is to take the symbol used for a spiral galaxy. All science could be said to be accommodated by a galaxy, the symbol forms an S shape for science, and it is simple and easily recognisable.
Wollongong, New South Wales, Australia
Undo brain
Having used interactive digital media all my life, I can confirm the reality of game transfer phenomena (GTP), in which in-game behaviour seeps into everyday life (24/31 December 2011, p 76).
My first experience was more than 10 years ago. I spent lots of time and effort creating a detailed picture with Microsoft’s paint tool, continually adding minute detail, examining it and, in fits of artistic temperament, undoing it. For a while afterwards, every spelling mistake I made on paper, or mathematical error in my head, would be followed by my brain commanding “CTRL + Z”, the Windows keyboard shortcut for “undo”. Rather unnerved, I abandoned my new hobby.
Mirror matter
Stuart Clark may be looking for dark matter under the wrong name (7 January, p 30). The idea that the universe contains a complete but invisible copy of ordinary matter dates back to 1957, when discovered that the weak nuclear force, one of four fundamental natural forces, only interacts with left-handed particles.
Since then, Wu and her team and a few others have investigated the possible existence of a reflected copy of ordinary matter where only right-handed particles interact with a right-handed weak force, so-called “mirror matter”.
Mirror matter seems not only to be viable as a dark matter candidate, but a better match for observations at the , and experiments.
Festive fieldwork
We can confirm the work of Brian Wansink and colleagues on buffet consumption (24/31 December 2011, p 50) from observations at a recent family event. As the first plates appeared on the table, a number of large, round shapes appeared in the gloom at the other end of the room.
As more food was added, these round shapes gradually moved closer to the table, so that when the buffet opened, the head of the queue was composed almost entirely of people with a high body mass index (BMI).
We propose the following equation: d = 1/gf where d is the distance from the buffet, f the quantity of food available and g for greed is a constant. We also propose that g is directly related to BMI for each individual.
From Liam Casserly
I now realise that my family has been involved in complex game theory every Christmas.
The process of picking foods based on knowledge of other people’s priorities is known in our house as “the war of the Roses tin”. My youngest brother is the only one to enjoy orange creams, so he can eat any other chocolate on early rounds of the tin safe in the knowledge that there will always be orange creams left.
Newport, Isle of Wight, UK
Weightlessness
You wrote that Microsoft’s “Kinect gaming sensor… helps calculate astronauts’ weight in zero gravity” (24/31 December 2011, p 16). I could do the same thing for only half the cost of Kinect. My device is a card with “zero” on it. Astronauts can read it whenever they want to find out what they weigh. Mass, however, is a bit more difficult.
For the record
• In the editorial “A blockbuster year” (24/31 December 2011, p 3), we should have said William Goldman wrote Hollywood memoir Adventures in the Screen Trade.