Time: It's all relative

The horror of the war in Syria - and the consequences for those affected - have been in the news a great deal recently. More than half of the Syrian population have been displaced and many have ended up in makeshift shelters. But, on a happier note, the University of Sheffield have found a way to make life a bit more bearable in at least one refugee camp. They’re repurposing the foam from used mattresses to make hydroponic grow beds. Chemist Tony Ryan had previously done research using foam to grow plants on roofs, so he was perfectly positioned to spot the opportunity when it came along, as he explained to Katie Haylor...

托尼- Zaatari难民营是12公里the Syrian border; there are 80,000 refugees in six square kilometres, and most of them were farmers before they had to leave their homes. Once the mattress has been given out, those people either move on, or the mattress gets changed; then the UN are stuck with this mattress that to them is dirty, and there's nothing they can do with it. They didn't know how to dispose of them even. So they showed me a warehouse full of mattresses, and I sent the most excited text message back to Sheffield university to say, "I know what we can do. We can give every refugee family a garden in an old mattress." So our task really was to convince them that they could grow things in foam, because where they were currently living was in the desert and nothing will really grow in the desert. Once we'd done that, they showed each other how to do it and then showed us how to do it even better.

Katie - The process involves filling waste containers with the foam and a nutrient solution. Seedlings are then placed into the foam, which supports the roots of the plants as they grow.

Tony - So for hydroponic horticulture all you need the soil to do is hold the plants up, because actually you provide everything for the plant in the nutrient solution that's delivered. Nitrogen, phosphorus, and potassium, the three main macronutrients, and depending on the plants that are being grown, the micronutrients are selenium, iron, magnesium...

Katie - What kinds of plants have people been growing? Is this for recreation? Is it for food? Is it both?

托尼,你won't be able to grow your main food calories this way. This is about quality of life. We've grown onions, radishes, cucumbers, lettuces, tomatoes, cauliflowers, squash, chillies, mint, coriander, and lots of other herbs; I got a WhatsApp message the other day with people harvesting strawberries from a collection of yogurt pots in a greenhouse; couple of hundred lettuces...

Katie - For experienced farmers who are used to growing in soil, was it quite hard to convince people to give it a go?

Tony - The key to getting Syrian farmers to change to something new is to get another Syrian farmer to explain it to them and be an advocate. We have a guy called Moaed Al Meselmani who's actually a Syrian refugee, he was a cereal researcher back in Syria. He helped enormously because he knows hydroponics can can speak Arabic. He convinced Abu Wisam, a 50-something Syrian engineer; he showed him and got him going, so he was the green-hand man that kept our hydroponic greenhouse working. You're far more likely to believe it if a Syrian farmer's telling you as opposed to some crazy English professor. And when you ask Maya, the young lady who works on the program, what she enjoys best about it, she says it's the smiles on the old ladies' faces because they can grow things again and they can see the color green. It gives people hope.

Katie - What have you learned from their experience of using this set-up?

Tony - So we have a research program in Sheffield on hydroponic horticulture and we've learned lots of little tricks about how to start plants growing, what the right watering regimes would be in an arid place. Lots of little technological tricks as well, and little inventions. So one guy turned up and he'd been growing herbs in a yoghurt pot that was full of foam, and then he put that yoghurt pot inside a bigger pot and used a repurposed pump from a soap dispenser. So every time he took a piece of mint to make his mint tea he recirculated the nutrient solution.

Katie - Do you think that would be the potential to make this system self-sustaining? I'm just wondering, is it always going to be reliant on the nutrient solution being provided? Or could it be sourced locally?

Tony - It wouldn't be difficult in terms of technology to go out of the refugee camp into commercial production. We'd like to take it into a business so that the refugees, as they move out into the community, if they don't get to go home, can actually generate a livelihood from being hydroponic farmers in a very water-deprived country. It would be competitive with growing things in polytunnels because you get better water usage, so you'd need less water in a very water-deprived place; and actually you get more efficient usage of the nutrient fertiliser solutions. The reason we're currently fundraising is to take it to every other UN refugee camp. They always have people with time on their hands. We know that growing things improves people's wellbeing and mental health. They always have dirty mattresses, and they nearly always have farmers. So it's a really positive thing. It turns two potential problems, a waste disposal problem and an idle hands problem, into something that gives people an awful lot of satisfaction.

The UK has seen widespread flooding this month following the arrival of storm Dennis and his sidekicks. The deluge has totally overwhelmed flood defences in many places. These defences are often necessary because poor land stewardship has drastically reduced the ability of the ground to store water. Until they were hunted to extinction, beavers were the UK’s land managers: their building projects helped to control how water moved through the terrain. So might one solution be to bring them back? Well, for the first time in four hundred years, they are swimming wild again, at least in one river in England. And - in the words of one correspondent, their impact has been “dam impressive”. Megan McGregor spoke to Alan Puttock, who’s one of the researchers keeping an eye on them...

Megan - Beavers are staging a comeback in a corner of southwestern England. Some accidental escapees into the River Otter provided scientists at the University of Exeter and Devon Wildlife Trust with an opportunity - to figure out if the beaver can still thrive in modern UK landscapes. And five years later the results are looking positive.

Alan - Beavers were able to thrive in our modern British landscapes, the population increased from two families to thirteen families over the course of five years and we found that overall beavers had a positive impact. This was in terms of holding back water and reducing flood risk, a massive increase in wetland habitat and biodiversity and also some other more social benefits, such as ecotourism. For instance, there were local villages that benefited from increased visitor numbers with people who wanted to come and see these wild animals.

Megan - Since beavers went extinct, we humans have created a lot of concrete paved cities and compacted farmland. These landscapes drain water very quickly and can contribute to increased flooding. Luckily beaver dams have a rather handy side effect for humans.

艾伦,在景观建造水坝,beavers increase water storage, but also the roughness of the landscape. So they slow the flow of water. So when you get heavy rain events, rather than water rushing off the land and flooding, for instance, downstream communities, you get this slower release of water from a beaver impacted sight. Beavers aren't the sole solution to flooding. They are part of the solution. We're not saying that you should take away these flood defenses that currently exist. What beavers can do is increase the resilience of flood defenses, so by reducing flooding a little bit you might not see, say, flood walls overtopped during flooding.

Megan - The beavers have such an impact on their environment because, like humans, they're what's known as ecosystem engineers - animals that change the landscape to their liking, rather than adapting to the landscape as they find it. And when two ecosystem engineers clash, a little bit of ingenuity is required for them to get along.

Alan - There were some negatives or management issues, such as localised inundation of farmland. If you have dams that are flooding land to what's deemed an unacceptable level, you can use something called a beaver deceiver. It's essentially a pipe to artificially lower the level of a dam. You essentially fool the beaver. The beaver thinks the dam's still there, but you can use this pipe to control the water level. So you still get much of the benefits of the dam, for instance, holding water back. You've got this habitat created, but you can lower the water level down to what's deemed an acceptable level, say for a neighbouring farmer.

Megan - So the beaver benefits can be big, but they require management to keep clashes with humans to a minimum. Luckily those hoping to bring the beaver back can learn from other successful examples of re-introduction, such as the programme in Bavaria in Germany,

艾伦-海狸re-introduction发生有计谋ple of decades ago. They probably have around thirty, forty thousand beavers there and they've introduced a very pragmatic management strategy where you have a couple of regional beaver advisers who are government funded, but then a whole team of volunteers within the farmer and land-owner community who can keep them updated and do easy tasks such as protection of trees or removing of dams if they're in a undesirable location.

Megan - And what does the future hold for British beavers?

Alan - We have now reported to government and we've provided them with all of our findings and they've extended the trial in River Otter by six months, which is to give them a chance to assess all the evidence and make a decision both upon the River Otter beavers and also beavers nationally.

Megan - If the government rules against the beavers, they'll have to be trapped and sent to a zoo.

Alan - I think we've shown that beavers can bring a whole range of benefits. I really hope that under appropriate management strategies we'll be able to expand beaver populations throughout Great Britain.

Time doesn’t just change over the course of a day. It changes as you go east or west. And as countries like the UK, traditionally a nation of seafarers, took to the waves, while sailors could work out their latitude - how far north or south they were - from the positions of stars or the sun, knowing how far they’d gone around the world - their longitude - was impossible. Because rough seas meant that a traditional pendulum couldn’t keep a clock ticking. This was called the Longitude Problem. Josh Nall from the Department of History and Philosophy of Science at the University of Cambridge joined Chris Smith and Adam Murphy to explain how it was ultimately solved...

Josh - Well, particularly in the British context, Britain is an expanding Imperial nation, it's active in the Atlantic slave trade, it has colonial holdings in places like India and that means long range seafaring; and knowing your position in East and West becomes extremely important when you begin to approach land so that you don't, for example, run aground and lose ships. And this was becoming by the turn of the 18th century a very serious problem for the British, in terms of losing ships going out to India and coming back.

Chris - And it just comes down to the simple fact that a clock would not tick and keep time reasonably when you're rocking all over the place on rough seas.

Josh - Absolutely. I mean at that point, not only could a clock not work, but when people like Isaac Newton were asked about the potential to solve this problem, he stated very clearly that it was effectively impossible to make a clock that would work at sea.

Chris - Why are we solely married to a clock as the solution? Indeed, is that the only way to solve this problem?

Josh - Well, many possible solutions were offered, but a clock seemed the best. For the simple reason that very intuitively we understand that as we move East or West, there's a time difference. So if you have a one hour time difference between two places on earth, we know that that's a 15 degree change in longitude. So if you know your local time, which you can find from the altitude of the sun, and you know the time at a reference location, which the British have always taken to be Greenwich observatory, then the difference in time gives you a very easy and quick read of your difference in longitude. So of all of the possible schemes proposed, it was always seen that timekeeping at sea would be the best solution.

Chris - And what, did someone throw down the gauntlet then? And say, "This is a major problem. It's costing us ships. It's costing us lives. It's costing us money. We need to solve it?"

Josh - Absolutely. So following quite a serious Naval disaster in 1707, where the fleet of the wonderfully named Sir Cloudesley Shovell ran aground on the Scilly Isles, and over 1600 British sailors were drowned. Parliament was pushed to act, and in 1714 they passed an Act of Parliament offering very significant financial rewards for anyone who could propose a workable solution to finding longitude at sea.

Chris - The one person who is often hailed as the hero of the day is John Harrison who was a watchmaker. He made timepieces didn't he? Was he the only player? Presumably, if there was a big financial incentive, didn't lots of people enter the race?

Josh - A very large number, to the point that there were a great many satires at the time of the number of absurd proposals that were being put forward! But certainly Harrison has become known, probably better than any other, because he is the person who first begins to develop clocks that can be effectively used at sea. But he's certainly not the only that the board of longitude is supporting and funding through the 18th century. At the same time that Harrison is working, there is an equivalently well funded project to try and develop an astronomical solution, which is effectively to use the moon as a clock because you can actually at any point on the earth if you measure the angle between the moon and certain given stars with the right kinds of astronomical data to hand, you can calculate time at Greenwich. And so that solution which involved using an instrument called a sextant and using astronomical tables that the Royal observatory had issued was also very well funded and was in a certain sense set up as something of a rival solution to Harrison. But in actual fact, the reality is by the end of the century, both techniques, taking working clocks but also taking sextants and astronomical tables, they tended to be used in conjunction.

Adam - Why would you want to use the system of measuring the moon and complex angles and sextants as opposed to just having a really good clock onboard?

Josh - There are two really good reasons. The first is that clocks are always going to be dangerously unreliable. So if your clock breaks at sea, you have no way of recovering the time that it was carrying, because it was carrying Greenwich time. And so you've then lost your one navigational technique. The second reason is cost. Chronometers were exceedingly expensive valuable pieces. Whereas taking astronomical tables, taking a sextant was a much more affordable, and therefore a much more general and repeatable technique.

Chris - So John Harrison invents a clock that solves the problem - A, how did he do that? And B, what did he win for doing it?

杰克,这真是一个终身旅程mak的时钟ing and clock improving that takes him to this eventual clock, which is generally now referred to as H4. And that's because it's the fourth major clock that he develops. And he starts working on these clocks in the early 1730s, and it's not until the mid 1760s that these are trialled at sea and demonstrated to be keeping time reliably at sea. And at that stage he has gone through many, many iterations and improvements, improving things like temperature compensation. You would think that motion at sea would be a really big problem, but if you think about it, pocket watches already existed. One of the really big problems alongside motion was temperature change, which really wreaks havoc with a clockwork mechanism because all of your metal parts expand and contract, and that just means your rate of timekeeping varies unreliably.

Chris - And what did, did he, when did he get the full price? Did it just go to him or any of these other solutions sort of co-awarded?

Josh - The answer is yes and no. Harrison got a lot of money from the board of longitude. They kept giving him money over the years to keep funding his work and his development, but at the end of his life, they didn't then decide to give him the full 20,000 pound award. Very controversially. Harrison was extremely upset. They were concerned principally about reproducibility. Their worry was that he had developed a clock, a single clock that worked, but they were extremely worried that they wouldn't then be able to produce more. So they offered him 10,000 pounds of the 20,000 prize if he would reveal the workings of his clock, which he did very reluctantly. And then they said they would give the other 10,000 if then the clock could be proved to be generally useful and usable. And this is the point that Harrison gets very upset and ultimately appeals to George III because he thinks he should just get the 20,000 pounds straight off.

Chris - And did they manage to reproduce it easily and give him the other 10,000 or did he go away an unhappy man?

Josh - They did. Ultimately parliament awarded him nearly all of the rest of the 10,000. They offered him 8,750 pounds. So no one in the end was happy because he got almost 20,000 uh, but not quite

Do you remember, as a child, journeys seeming to take forever on the way there, but then much less time on the way back. Do the years seem to be flying past increasingly quickly? Why? Luke Jones is from the University of Manchester and he joined Chris Smith and Adam Murphy...

卢克-这取决于什么类型的时机we're talking about. Although we talk about people who are having a sense of time, there's different types of timing judgment that we make. So you have a sense of duration, how long things lasted for. You have a sense of where you are in time, you know, when am I or what time is it now? And you have what we call passage of time judgment. So how quickly time seems to pass for you. And there seems to be different mechanisms that control these different types of timing judgment

Chris - And how good are we on average at working out how fast time is passing?

Luke - How quickly time is passing, we're very variable at it. In fact, it's a very weird question, if you think about it. We know that time passes at the same rate, unless you're close to a black hole or travelling at the speed of light. But if I say to you that time passed more quickly when I was playing on my Nintendo this afternoon, or that it crawled when I was waiting for a taxi to get here, then you understand what I mean. There seems to be this disconnect between our knowledge that time passes at the same rate and the way we feel time passing.

Chris - I remember reading in the book Catch 22, that the main character says he likes spending time during his days off with a certain other character 'cause that person's really boring and makes time go really slowly. So it seems to make the leave last longer. But why is that? Why do things that are very engaging seem to make the time whiz by, whereas things which are tedious seem to take forever?

Luke - So although we think of those two extremes, so the unpleasant situation, and the pleasant situation being kind of polar opposites of each other, they seem to operate in quite different ways. So in the pleasant situation, you're probably not paying attention to time. You're engaged in the event, you're not looking at the clock. And it's only when you receive a phone call, or something alerts you to what time it is, that you kind of retrospectively think, Oh my gosh, so much time's past. When you're in an unpleasant situation, you're aware of it at the time. You're aware of every single second ticking, ticking along and crawling along. So the, the, the pleasant situation of time flying seems to be a kind of retrospective or we look back and infer that it must have passed quicker.

Chris - I read one proposal by a group of experimenters, who were throwing themselves off bungee platforms while watching a watch, and saying their theory was that because they were taking more sort of, mental snapshots provoked by fear, their memory was much richer for the experience, that when the brain worked out, well roughly how long something had took, because it had so many mental images of what had happened in that period of time it assumed it must have taken longer than it did, which is what was creating the sense of time slowing down under that circumstance.

Luke - Yeah. So that's really interesting, so there seems to be, we haven't worked this out yet, but there seems to be an interesting link between the rate at which we process information, and our perception of how quickly or slowly time passes. So in those extreme situations, and a classic example is a car crash. So when people talk about that they say "it seems as if time slowed down, seems as if the van coming towards me was in slow motion." And you can imagine that in that situation you might have a kind of big injection of adrenaline, you know kind of fight or flight response, and this speeds up the rate at which you process information. If we're using that as a kind of feel of how quickly time seems to pass, then you can imagine that there'd be a link between those two things.

Chris - And do you think that that is what is happening with age then? That because we're processing information a bit less because there's less novelty in everything for us, it gives the perception that time is passing quickly because the brain's on autopilot more?

Luke - Possibly. The age thing is a really weird thing, the more you think about it. People have noted this idea that the time passes more quickly as you get older for hundreds of years, and there's an old idea of a year being a smaller and smaller ratio of your age as you get older, or maybe you process less information, but hardly anyone's actually collected any data on this and those that have, have found that it doesn't quite scale up in this way. So in order to feel that time is passing twice as quickly, you might need to be four times as old. And there's some evidence that it actually peaks in middle-age rather than carries on going as you get older. But the real mystery is what do people really mean? Is the question meaningful? If I ask you how quickly time passed now compared to when you were half your age, you'll give me an answer, but do you really carry around in your head a model or a memory of how quickly time passed when you were younger?

Adam - I find myself every autumn starting to say things like, "Oh, Christmas is coming earlier every year." What's going on there?

Luke - Now, isn't that strange? Do you think that you would update your notion of how quickly Christmas comes around? Well, why? Why are you caught out every single year? It's quite an odd one that. Again, it's whether that question has meaning. We've certainly feel it and people talk about this anticipation of Christmas, but it's odd that people don't update their notion of how quickly it takes for a year to pass.

Chris - And Luke, are there any things that can go wrong that will affect our sense of timing? 'Cause we've talked about healthy people all the way through so far. Are there any situations where people's time clock goes wrong and their perception of time is off?

Luke - There's very little evidence. It seems as if there's something so intrinsic about your sense of time, or at least your orientation in time that if you lose that you've kind of, you've already lost a lot of other cognitive strategies. So actually looking at those cases, there's hardly any of them to draw any conclusions from.