Editor's pick: Causes of tipping points in risk perception
Bryn Glover wonders what causes switches in perception such as that over smoking (Letters, 10 November). Tipping points in risk perception are not unlike triggers that set off revolutions. It may be a single event or news report. One Tunisian market trader, Mohamed Bouazizi, set himself alight to protest corruption and his inability to make a living – and triggered the Arab Spring. Sympathy for refugees to Europe rose after publication of a photo of a Turkish police officer holding a drowned child by the Mediterranean. The TV programme alerted us to the damage plastic does to the oceans and wildlife, and with an earlier media campaign built support for such measures as the .
At every possible tipping point, vested interests quickly try to dampen things down.
Will there be a trigger for climate change that overcomes this? I fear it will instead take a prolonged heatwave with high humidity in a large south Asian city, causing heat-stress deaths maybe in the millions.
Gravitational wave researchers respond
The LIGO and Virgo collaborations wish to give our perspective on what we see as inaccurate claims about the robustness and transparency of our research in a recent article by Michael Brooks (3 November, p 28).
We did contact Andrew Jackson's team both before and after the posting of their article on the event labelled “GW150914”, and had extensive email and in-person exchanges with them.
LIGO signal data are in fact available to all. The time series from all LIGO's signals are posted on the ; also software and tutorial links are found there.
In our on GW150914, Figure 1 demonstrated the clear presence of a signal compatible with general relativity in LIGO data. Small correlations in “residuals” are not indicative of a lack of signal. A wealth of peer-reviewed papers cited in that article provide many answers to questions raised in your article. Those interested in how the “glitch” was removed from the data for event GW170817 can read our for the paper on it.
We are preparing a paper for peer review that explains the approaches the LIGO/Virgo collaboration uses.
Science thrives on scepticism and a desire to understand deeply how a result has been obtained. We welcome efforts to further replicate and extend the work we have done in interpreting the gravitational-wave data, and are continually working to make our data and tools even more accessible. The Virgo and LIGO laboratory and collaboration leaders endorse this letter.
We have named gravitational waves correctly
First class post 鈥� 24 November 2018
One imagines that people on those planets once had a vote to be better off on their own
Jennie Kermode of the discovery of two new rogue planets that do not orbit stars (17 November, p 19)
Wealth, education and lifespan in Africa
Debora MacKenzie reports a finding based on data from 174 countries that more education is what makes people live longer, not more money (28 April, p 12). I used this as a springboard for a school maths assignment.
I calculated the correlation of wealth, education and life expectancy, using data only for Africa. I found that education – measured by the literacy rate for over-15s – had a low correlation to life expectancy (r = 0.3782). Furthermore, I found a stronger correlation between wealth – GDP per capita – and life expectancy (r = 0.4036). Both are relatively low correlations, given that a direct correlation is r = 1.
I conclude that economic empowerment is a stronger factor than educational empowerment when determining life expectancy in Africa.
Using my electric car is a small step forward
I accept that electric cars are a cause of carbon emissions, as Tom Watts points out (Letters, 29 September). But I note that the UK's national grid averages suppliers across the country.
While my Nissan Leaf was on charge between 2 am and 4 am this morning, 31 per cent of the electricity used was generated from gas and coal, while 69 per cent came from wind and nuclear. The car provides information on energy use, helping me to drive more economically. Its limited range makes me plan journeys more carefully: can I combine several errands into one journey?
I am not changing the world here. But I am making a small step forward.
Consider a wind farm as a sort of forest…
Sean Confrey raises some interesting questions about wind farms and their possible effects on the weather (Letters, 3 November). While it must be true that any obstruction to the wind will have an effect, such effects must surely be very small, on the same order as the effect a row of very tall trees has on the wind. In the case of trees, the wind will create movement of the branches and leaves, and possibly the roots in the ground. These movements will emit a small amount of heat, which will be released into the atmosphere. Downwind of the trees, the speed of the wind will be reduced, so that any loss of energy from the ground to the air will be reduced. Do these two processes cancel each other out?
In the case of the turbines, because there is little friction in the system, most of the wind's energy will be converted into the movement of the blades and thus into electricity. There will be a reduction in wind speed downwind of the turbines, but I imagine this would be small.
One of the great advantages of using wind, tide or solar power is surely that there is an abundance of energy in these sources, and that we only need to use a fraction of what is available to satisfy all of our energy needs.
Explaining origins as the common people do it
Philip Ball says Stephen Hawking told us that God is all about explaining the origin of the universe and responds that no theologian ever did this (20 October, p 44). As a former Christian who regularly debates such things with theists, it seems to me that Ball is out of touch and struggling with the reality of at least part of the argument. Hawking is referring to common people's views.
for the existence of deities hold that whatever begins to exist has a cause; the universe began to exist, therefore the universe has a cause. Like other first-cause arguments, they are used by apologists around the world, of all theistic faiths. Many now quote the “” set out by William Lane Craig.
The person on the street will often say “How else have we got here?”. Ball isn't correct to refer the argument to theologians or to deny this is a cause of belief.
Stable and unstable locations in space
You say the Earth-moon system has a set of five gravitational balance points, where the gravitational forces from Earth and the moon balance out, and that objects can get trapped in these regions, called Lagrange points (3 November, p 8). You could have made it clearer that objects cannot get trapped in three out of the five, which are unstable.
What kind of radio bursts are these?
As a radio-communication engineer, I am surprised at the choice of the term “fast radio burst” (FRB) for the mysterious bursts of radio-frequency energy detected in space (27 October, p 8). Surely these emissions travel at the same speed as any other electromagnetic energy?
Better terms would be: brief radio burst (BRB) or short radio burst (SRB.) An appropriate adjective starting with “F” would preserve the acronym, but a quick – or, better, a brief – search found nothing suitable.
The extraterrestrial hunt is a never-ending story
Douglas Heaven says our hunt for alien life is far from over (6 October, p 15). The frustration felt at the absence of alien life detection thus far needs tempering by a thought not mentioned. The writer Arthur C. Clarke is reported to have observed that “we are either alone in the universe, or we are not”.
We can have a definitive answer on whether there is life out there only if we detect transmissions from an exoplanet – or if someone travels here and makes a dramatic entrance. There will never be a scenario in which we can declare there is no alien life. All we can conclude is: there is no other life, or we haven't found it.
Excessive hours are a failure of economies
Michael Cook complains, rightly, about games developers working excessive hours (27 October, p 24). He notes that the economist John Maynard Keynes predicted that automation would lead to shorter working weeks and this hasn't come to pass.
The problem is by no means confined to the technology sector. Those in employment are expected to work long hours while others are unemployed. That is a clear failure of current economic systems. Notably, total working hours per year vary considerably between countries, even those with generally similar economies.
Electrical repairs put me in a trance-like state
Michael Marshall thought he was weird experiencing autonomous sensory meridian response (ASMR) while watching towel-folding (3 November, p 35). In a life spent in laboratories, I used to get exactly that tingle when engineers came to fix or service any piece of electrical equipment. I would find myself in a trance-like state that was quite hard to shake off. Even the Bosch engineer working on the washing machine at home could induce it.