Digital primordial life has a message for us (1)
You report that self-replicating virtual life forms have been found to emerge “from a digital primordial soup”, an example of order arising in seemingly unlikely circumstances. Is it possible we have overlooked something fundamental about the universe? Have we failed to create a theory to explain the existence of order, which seems to emerge wherever there is available energy(13 July, p 8)?
From the structures of subatomic particles to those of galactic superclusters, order is evident in the universe. Ever since the earliest moments in time, when the cosmic microwave background revealed its patterns, up to the present day, orderly structures are the norm.
Given the ubiquity of the evidence for the development of order from chaos, it seems likely to me that there is a corollary to the laws of thermodynamics governing this process.
Digital primordial life has a message for us (2)
That self-replicating virtual life emerged from random data surely increases the probability that we are living in a simulation, the possibility of which was raised by philosopher Nick Bostrom. One of the key notions connected to this, he suggested, would be the existence of posthumans capable of running simulations of evolutionary history. It now turns out this could be far easier to do than previously imagined.
Look to the oceans for LUCA's birthplace
You report evidence of an earlier origin of LUCA (the last universal common ancestor of all life), around 4.2 billion years ago. If LUCA emerged then, this would give just a 300-million-year window between the formation of Earth’s surface and life’s origin (20 July, p 9).
It seems unlikely this could have occurred on the hot, primordial surface. A less disruptive location would be ocean hydrothermal vents, where chemosynthesis 鈥� in which carbohydrate is made in the absence of light 鈥� takes place.
Overcoming the fear of exercise is really hard
Your article on psychological barriers to exercise only addressed one aspect of the issue. I doubt I am alone in associating exercise with fear, even when someone else is doing it. I had to take my courage in both hands to read all your articles on exercise, and by the end I had definite signs of anxiety: racing pulse, grinding teeth, fist clenched as if fighting pain (27 July, p 38).
I have pushed through such feelings and taken up exercise routines in the past, sometimes for months. The fear never reduced, it just became part of the process. People don’t like to admit fear. It is easier to claim a lack of motivation. I suspect a lot of psychological barriers to exercise aren’t about the absence of a positive, but the presence of a negative.
More ways to store renewable energy (1)
Gravitricity’s energy-storage scheme uses a 25-tonne weight dangled in an old mine. Since a great deal of wind energy is generated offshore, we could use excess electricity to pull a large air-filled float down to the sea floor and, in times of need, use its rise to generate electricity (20 July, p 36).
To displace 25 tonnes of water, we would need a 25-cubic-metre float 鈥� a sphere with a radius of less than 2 metres. We might want a much larger one, of course.
More ways to store renewable energy (2)
Roger Harrabin speaks of massive energy-storage projects involving weights in deep mines, but it occurred to me that all new-build houses could include some sort of double wall with an individual “falling weight” device, wound up by the output of solar panels or wind generators during daytime and allowed to gradually fall in the night, generating light and heat.
Did these more ancient Americans arrive by sea?
Evidence of human occupation in South America now dates back as far as 21,000 years. If correct, this would predate the currently accepted arrival of people in the Americas by at least 1000 years. It would also support my suggestion (Letters, 2 May 2020) that the Americas were first occupied by Polynesian people escaping from atolls that were inundated by rapidly rising sea levels, rather than via a land bridge between north-east Asia and North America (27 July, p 18).
How we keep aircraft safer far from land
Aviation safety over oceans isn’t solely dependent on navigational systems like GPS, which, as you report, have been subject to jamming. Aircraft carry a traffic alert and collision avoidance set-up, an independent radar-based system, to reduce collision risk. It works well for aircraft in the usual flight/cruise conditions, assuming the crew pay attention to alerts and advisories (20 July, p 14).
Latest fusion delay is a real let down
At the age of 78, it was very disappointing to read that the ITER fusion reactor project in France is apparently not going to be fired up in my lifetime, if ever (6 July, p 13).
Life choices have kept my ageing brain sharp
The idea that middle-age lifestyle choices can influence how your brain ages is interesting. When I was 42, my husband died, leaving me with four children and debt. I went back to college, retrained for a different career, took my driving test, remortgaged and got on with life. I got a job, joined a union and did a degree with the Open University (I started reading 快猫短视频 then 鈥� a good result!) (20 July, p 32).
A few years ago, when I was almost 70, I left my home of 30 years and moved more than 600 kilometres away to live in a place where I knew nobody. I think you need to give yourself challenges in life to keep alert and fresh. I am sure this has positive outcomes for brain health.
For the record
Typical simulations of the universe assume gas extends by 10 to 20 per cent outside a galaxy’s outer limit (27 July, p 10).