More takes on the enduring mystery of time (1)
We have elegant concepts of time that enable us to converse systematically about past, present and future events on the scale of our solar system and to some extent well beyond it (18 June, p 38). However, we are required to prove the need for any assertion that these concepts aren’t merely useful tools, but have physical reality.
If the universe consists simply of the unfolding of chains of cause and effect, no paradoxes arise. The arrow of time is implied. There is no “time” to travel in.
All event chains in the universe appear to vary in speed of execution as a function of the strength of gravity they are subjected to and the speed they are moving at relative to the speed of light. Clocks are merely cyclic chains of events. Light propagation within the gravitational field and at the relative speed of a clock would be slowed in the same way as all the processes within and around the clock itself, and the result of the measurement of light speed would always be the same.
What else do you need and why?
More takes on the enduring mystery of time (2)
You write that “[time] stops everything from happening at once”. Surely it is one step more fundamental than that. Without time, there can be no change. Nothing happens. Nothing can happen.
Even if the “present” situation represents a potential cause, without time, there can be no effect. That would pre-suppose change, which requires there to be elapsed time.
In addition, it is argued that the “heat death” of the universe in far-flung time, should it occur, loses the “arrow of time”; the immediate past will be indistinguishable from the future.
However, there is the well-established thought experiment of the “Boltzmann brain”: a sentient entity could just pop into existence by statistical fluke, as indeed could any structure of arbitrary complexity, given enough time. Thus chances are that this heat-death phase will be riddled with these sentient entities, and why not also a plethora of clocks? The arrow of time should thus be preserved.
For greener fashion, pull on some bamboo
Three cheers for Graham Lawton, for the overdue discussion of the waste of the fashion industry, both in the greener climate debate and the plight of many of its workers (4 June, p 38).
To add to the points made, the use of fabric derived from bamboo should also be encouraged. Technically a grass, this plant is prolific, therefore widely available, and its use in fabrics requires less water and chemicals than many other sources of fibre. It is also biodegradable.
Also, a plea for kindness on another fashion front: sheep and the use of wool. There is precious little thought for the creatures from whose skin it is removed.
No need to go nuclear to temper global warming (1)
Graham Reynolds asks us to choose between long-term storage of nuclear waste and “worldwide, incomprehensible damage to the climate” (Letters, 25 June). That would be a good argument for nuclear power if we had only two choices. But we don’t.
We can also choose to sharply reduce energy waste and to rely on power from the sun, wind and tides to heat our homes and move our cars, buses and trains. This is the pragmatic solution because it needs only things we have already designed and built, and whose costs fall each year. It frees us from dependence on an industry that just can’t deliver on time and within budget. Why wouldn’t we choose the renewable option?
No need to go nuclear to temper global warming (2)
Nuclear power isn’t just problematic because of the carbon costs of uranium mining, construction and waste disposal.
It is also troublesome as anything like an earthquake, tsunami or terrorist attack that affects a reactor is also liable to take out the back-up safety generators needed to remove and isolate the fuel in the reactor to avert catastrophe. The Fukushima disaster showed this.
Then there is the fact that nuclear plants require huge amounts of water, so are mostly in coastal locations. With sea levels rising, our descendants are going to have a huge problem. There is no way of making the sites 100 per cent watertight when many may be submerged within the next few centuries.
Climate scientists must become a lot more vocal
You say that most climate researchers fear to tread into the arena of politics (Leader, 11 June). In my opinion, that is their biggest mistake.
Most politicians aren’t scientists, so they don’t speak the language of science and don’t understand the methods. Even those who are able to understand what the scientists are saying are left with the question that no Intergovernmental Panel on Climate Change report had ever answered in clear terms: “What should I do?”
Politics is all about taking decisions, so when you want politicians to act, you not only have to explain the problem in terms they understand, but most of all you have to tell them what you expect them to do.
快猫短视频s, you are the experts, so you know what action needs to be taken. Tell them.
Adoption of insect diet may be politically tricky
The adoption of insects and lab-grown meat in place of the consumption of traditional meat and dairy products is an intriguing possibility (30 April, p 12). For insects, as living things, this raises a question of how will they be “harvested”.
However, I believe the biggest hurdle will be the “yuck” factor. The article suggests that if consumers won’t make these changes voluntarily, then governments will need to force these foods on them.
Any political party promoting a policy of compulsion would soon be consigned to the political wilderness.
A nice coat of ivy is the best insulation for your walls
When it comes to what is best for external wall insulation, common ivy (Hedera helix) is a good bet, keeping homes warmer in the winter and cooler in the summer (Letters, 11 June). As well as being biodegradable, it captures carbon, provides food and homes for insects and birds and requires no fixings.