Time and space
In his letter, Michael Crick makes the mistake of conflating the flow of time with intervals of time (15 November, p 33).
Peter Lynds’s reasonable and widely accepted assertion that the flow of time is an illusion (25 October, p 33) does not imply that time itself is an illusion. It is perfectly meaningful to state that two events may be separated by a certain duration, while denying that time mysteriously flows from one event to the other. Crick compares our perception of time to that of space. Quite right. Space does not flow either, but it’s still “there”.
Back where we belong
Congratulations New 杏吧原创! You have put the Earth back in its rightful place at last (Pull-out map, 22 November). It’s the biggest thing on the map and the sun is hiding insignificantly among the planets.
The Earth looks reassuringly flat too. You have certainly managed to turn the tables on that Copernicus bloke.
Snowball oceans
I wonder if ocean planets wouldn’t have a serious problem with runaway cooling effects (15 November, p 38).
Lately there has been much talk about the Snowball Earth theory, according to which the whole planet has frozen over several times. Only carbon dioxide of volcanic origin, which slowly built up in the atmosphere over millennia, was able to thaw the ice ball. But volcanic CO2 on frozen-over ocean worlds would not be able to reach the atmosphere because it would never get through the ice shield, which would be thousands of kilometres thick.
Letter
The map of the universe is most impressive and thank you for that, but it is of little use as a navigational tool. It gives the position of the stars at the time that their light was emitted, as much as 10 billion years ago. Can anyone say where the stars are now, or more importantly where they will be so that I can head my ship in the right direction?
Valerie Jamieson replies:
鈥� During the billions of years it has taken light from distant stars and galaxies to reach us, the cosmos has been expanding, so distant objects are even farther away than they were when they first beamed out their light.
However, Richard Gott and Mario Juric’s map takes this expansion into account, so you could use it to work out how far you would have to travel. Of course, by the time you arrive some stars will have ended their lives in supernova explosions and may not be there any more.
Tears without pain
I found your short news item on “sense with no feeling” intriguing (22 November, p 19). As a person with an autistic spectrum disorder (Asperger’s syndrome), I find the concept of a somatic effect normally associated with a negative emotion (such as the galvanic skin response mentioned in the article) without the expected accompanying emotion to be entirely consistent with my own personal experiences.
When I witness real or apparent pain or injury being inflicted on someone else, the experience is usually accompanied by a distinctive cutaneous sensation similar to pressure and usually felt in the upper backs of my legs (although it can be somewhat more generalised).
I have also been known to shed tears under stressful conditions without having any overt perception of negative emotion such as sadness, anger or fear.
Midwestern Hebrew
I can certainly understand Adoram Erell’s frustration when trying to speak Hebrew to his cellphone (1 November, p 31).
When text-to-speech was new, a few of us were playing with software that could take a text in English and read it out loud. We quickly got bored and decided to teach it to speak Hebrew. Fiddling with the transliteration I managed to make it speak well enough to be understood, but much to our amusement it had a very heavy American midwestern accent.
Antimatter galaxies
“It is a mystery of cosmic proportions: why is the universe filled with matter and not antimatter?” your story on antihydrogen begins (1 November, p 9). Really? Or is this just an unnecessary assumption that complicates our understanding of the universe?
After all, is there any direct evidence that other star systems are not made of antimatter? Given the scale of interstellar separation, and the virtual impossibility of interaction between the constituent particles of each system, this would seem entirely plausible. And if not on this scale, then perhaps even larger. Matter and antimatter galaxies? Galactic clusters? Galactic super-clusters?
Electric overload
Am I the only one alarmed that your letter writer Gregory Nicholls regards 1800 kilowatt-hours per month as an acceptable level of power consumption for a household (11 October, p 30)?
Let’s put this in perspective. It is an average of 60 kilowatt-hours per day or a 2.5-kilowatt continuous load. Assuming 100 million households in the US with similar levels of power consumption鈥ek! No wonder the planet is in trouble!
My household doesn’t use anywhere near this amount of energy, which is a good thing too because my house is solar-powered and, as Nicholls points out, it would cost a lot to install a photovoltaic system that could cope with this load.
When installed, my power system cost less than half the upfront cost of connecting to the power grid. Since I don’t have to pay bills or cope with the inconvenience of blackouts, I see this as a great investment.
I’d love the challenge of reducing your power bill, Mr Nicholls.
Watch that hydrogen
I found the article about the environmental aspects of increased use of hydrogen very enlightening (15 November, p 6). Another aspect is the risk of explosions around cars and filling stations.
In petrochemical plants, hydrogen is often an unavoidable and unwelcome guest. For instance, so-called “flameproof” equipment is not permitted in areas handling hydrogen because the gas can penetrate gaps that are barriers to ethylene, ethane and other heavier organic compounds.
In such plants, gas detectors are scattered about and operators are properly trained. How is it that hydrogen is now considered a benign substance that the untrained general public can safely top up and drive with, and put in their garages?
Joanna Marchant writes:
鈥� Although hydrogen is explosive, quite a high concentration is needed to make it explode in air. If ignited, leaking hydrogen is much more likely to burn than explode, in contrast to a tank of petrol. For a fuller explanation see .
Like-minded mobiles
You reported on “intelligent tags” for helping people to meet others of like mind, the idea being that you wear an interactive tag on your person (15 November, p 26).
It’s a great idea, but all this additional hardware seems unnecessary as most people already carry a more than suitable platform: the mobile phone. All that is lacking is the software.
Letter
Your article raises the possibility that some convicted felons freed from prison on the basis of DNA testing may in fact be guilty.
Hitherto, when a rape victim’s ID of her attacker conflicted with DNA evidence, it has been taken as an example of her unreliability.
Double identity
Claire Ainsworth’s review of the astounding phenomenon of microchimerism is very enlightening (15 November, p 34), but there is another form of microchimerism that will become increasingly important in the context of medicine.
While the reported form of microchimerism explains the presence of “foreign” cells in our bodies, mutations in our own genome create a subpopulation of cells slightly different from those that created us. The most dramatic effect of such mutations, which usually occur in adult life, is cancer. However, mutations may also arise during embryogenesis in progenitor stem cells. These early mutations may lead to a specific tissue developing with a different genotype from the rest of the body.
Pharmaceutical companies are in for a surprise when the highly tailored drugs (or drug doses) designed for a patient’s genotype, as determined by DNA analysis of a blood sample, do not have the predicted effect. The result may even be detrimental. The lesson to be learned here is that genotyping really ought to be carried out on the tissue that will be targeted by the drug.
Micro ignorance
Yes, Stephen James, it might well be that instead of “microwave cooking zaps nutrients”, it could be a case of “overcooking zaps nutrients” (15 November, p 33).
However, what does this say about the priorities for public health (and research) that these sorts of questions remain unanswered? Decades after microwave ovens were let loose on the public, we still know very little about their effects on food, and even less about the effects on consumers of this form of cooking.
Size of Wales
Feedback rightly highlights the common use and abuse of everyday size comparisons in scientific articles (8 November).
However, in the otherwise excellent article on box jellyfish in the same issue (p 34), you describe Chironex fleckeri as being “a brutish creature the size of a birthday cake”. Does that mean its tentacles are the size of candles?
Star turn
Marcus Chown writes that “hardly anyone” knows the name of the Harvard astrophysicist Cecilia Payne nowadays (8 November, p 52). He is no doubt right as far as the general public is concerned, but my recollection from the early 1950s, when I was a working astronomer, is that Cecilia Payne-Gaposchkin, as she was by then, enjoyed a high professional reputation. She was a leading astrophysicist in the intellectual sense, but perhaps not in the hierarchical sense.
Confusing the enemy
The misleading signposts to Framlingham (Feedback, 8 November) can be explained as a hangover from the second world war. During the war, signposts in Norfolk and Suffolk were deliberately scrambled so as to create chaos and confusion 鈥� not to mention paranoia 鈥� in case of a German invasion.
I remember that around 1955, when these signposts were still widely in use, things were often very confusing in Norfolk.
Love's mystery
It will not be a shock to learn that yet another of your readers is unable to share Keats’s belief in the power of science to “clip an angel’s wings, conquer all mysteries by rule and line”, and “unweave a rainbow”. Yet your article on love brought this poem to mind (22 November, p 18).
As one having recently “fallen in love”, I had no desire to discover that this feeling derives not from the smooth charms of the guy pursuing me, but rather from the enthusiastic exertions of my right caudate nucleus and right ventral tegmentum.