Feedback is our weekly column of bizarre stories, implausible advertising claims, confusing instructions and more

Physics of defecation

快猫短视频 editor Alexandra Thompson passes along a press release from the University of Amsterdam entitled 鈥�Hoe de poep-emoji zijn vorm kreeg鈥�. A hasty bit of translation reveals that this means 鈥淗ow the poop emoji got its shape鈥�.

For those whose knowledge of emoji doesn鈥檛 extend beyond the smiley face, a spot of explanation may be in order. Buried in the emoji alphabet is the poop emoji, which, though it can take many guises IRL, is shaped like a sort of conical tower made up of coiled ropes of faeces. The Emojipedia website helpfully compares it to 鈥渟oft-serve ice cream鈥�, which, in these heatwave-addled times, is a frankly monstrous image to put into people鈥檚 minds.

Readers who saw the 2017 cinematic triumph The Emoji Movie may recall that the poop emoji was a significant supporting character, its voice provided by none other than Shakespearean starship captain Patrick Stewart. We therefore encourage you to imagine that the rest of this item is being read by Stewart in his most stentorian tones.

The press release directed us to a of the physics of lugworm poop, published in Nature Communications in April. The authors explain that many animals produce coiled poop, as illustrated by the emoji, including earthworms and some mammals. This shape emerges from 鈥渢he coiling of fluid 鈥榬opes鈥� falling onto a rigid surface鈥�, which is controlled by a combination of gravity, inertia and viscosity.

Lugworms are an interesting exception, because they defecate upwards, against gravity. They live in U-shaped burrows in intertidal sand flats. At low tide, each lugworm positions its anus just below the burrow entrance and poops upwards, leaving a deposit on the surface of the sand flat.

Yet despite defecating in the opposite direction to most animals, the lugworms still manage to produce a coiled poop. Somehow, this manages to hold its shape despite the risk of 鈥渂uckling instabilities鈥�. Resistance, at least to buckling instabilities, is apparently not futile.

Furthermore, the radius of the coil is 鈥渄etermined solely by material properties and rope geometry鈥�, unlike in animals that defecate downwards, where the height of the fall is a key factor.

The researchers go on to describe this in great mathematical detail, and to show that the same model can accurately describe the coiling of other substances, such as rice noodles and spaghetti. There is something oddly beautiful about all this: it turns out the universe isn鈥檛 so badly designed.

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A qeux for Bayeux

Queueing, and how to optimise it for maximum fairness and efficiency, is an intriguing little area of applied maths. If one train is late arriving at a station, should it be prioritised 鈥� perhaps causing a delay to another train 鈥� or made to wait? What would be fairest to the people on the trains, and the most efficient way to run the railway system?

Feedback has no idea, but we do know that history buff and chief subeditor Kelsey Hayes had a trying experience of online queueing courtesy of the British Museum. Kelsey is a paying member of the museum, so she got an email in early June notifying her that it would be showing the Bayeux tapestry from September: the first time it has been in the UK for 900 years. Members would get access to an early ticket sale, two weeks before tickets were made available to the general public.

The email advised Kelsey 鈥渢o register to book鈥� a slot. Or, as she put it, 鈥渋t鈥檚 a sign-up to do a sign-up鈥�. She booted it up, only to discover an online queue that was 鈥渙ver 1400 people deep and takes 20 minutes to get through鈥�.

Once she had gone through the process, Kelsey learned it was an exercise in what she called 鈥済etting members to have their log-in details in order, so that there isn鈥檛 a register/reset password apocalypse in a couple of weeks鈥�. Never before has Kelsey, or anyone Feedback knows, been asked to sit in a virtual queue for 20 minutes in order to reset a password.

Two weeks later, member booking finally opened. 鈥淭ook me 4 hours in the queue to get a time slot,鈥� Kelsey reports. She鈥檚 going to be so mad when she finds out it wasn鈥檛 made in Bayeux and isn鈥檛 even a tapestry.

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Not my bag

Feedback always enjoys laughing at hubris, so it gives us considerable pleasure to deliver the news that a bag made of a trademarked substance called 鈥淭-Rex Leather鈥� at a Paris auction in June. The bag was expected to go for more than $500,000, but in the end the bids never even approached that.

It was apparently created using from a Tyrannosaurus rex femur, and Feedback is going to stop you right there. Leather is made from skin, and this 鈥淭-Rex Leather鈥� isn鈥檛 made from T. rex skin.

Collagen is just one of many proteins and other biomolecules found in skin. To recreate T. rex skin properly, you would need a full T. rex genome in order to grow T. rex skin cells. Good luck with that: the oldest known preserved DNA is from a site in Greenland and is 2 million years old, while T. rex went extinct perhaps 66 million years ago.

We don鈥檛 have any T. rex DNA, let alone a full genome, so we can鈥檛 grow T. rex skin cells. Feedback would like to think this is why the bag didn鈥檛 sell, but we fear it might just be because it鈥檚 a distinctly unfashionable colour.

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Got a story for Feedback?

You can send stories to Feedback by email at feedback@newscientist.com. Please include your home address. This week鈥檚 and past Feedbacks can be seen on our website.

A living organism is made from components that aren鈥檛 themselves living. This simple statement has profound implications. For one, it means that there is no mystical force that animates us and other life forms. For another, it means that it should be possible to build a life form from scratch 鈥� and we are now a step closer to doing so.

Artificial life has been the guiding light of synthetic biology for some time. In 2010, biologists at the J. Craig Venter Institute in California synthesised the stripped-down genome of a bacterium and inserted it into the chassis of another cell, emptied of its own DNA. The resulting organism, with a record-low number of genes (473) was able to grow and reproduce. But even then, scientists didn鈥檛 understand what a third of those genes were doing, or whether they were even needed. Instead of rebooting an existing cell with a synthetic genome, we need to build an organism from the ground up.

That is what scientists at the University of Missouri are now attempting. The SpudCell 鈥� named both to evoke Sputnik and the dawn of the space age, and for its resemblance to a potato 鈥� is an entity based on just 36 genes. It self-assembled when the genes were supplied with all the building blocks necessary for life, forming cell-like bubbles and making proteins.

SpudCell represents a significant breakthrough in the creation of artificial life

But that鈥檚 it. The SpudCell can only make proteins because it is supplied with ribosomes, the crucial cell components that make proteins. It can鈥檛 metabolise food, supply itself with energy or reliably divide and reproduce. It isn鈥檛 alive, and it needs intensive care just to perform its basic functions. Nevertheless, the SpudCell represents a significant breakthrough in the creation of artificial life. If a modern living cell is a jet airliner, the SpudCell is the rickety wooden-and-cotton proto-airplane made by the Wright brothers.

Better versions will soon follow, with potentially transformative applications. The hope is that synthetic cells will one day be able to supply materials that are currently derived from fossil fuels, such as plastics, fuels and fertiliser. That is keenly needed. But the work in understanding how a living entity operates will shed light on what life needs, and how it emerges from dead materials. If we crack this ultimate mystery, synthetic biology will have really delivered.

Down under

Places to go

Feeling tense

The heatwave that swept Europe last week saw many temperature records broken, leading people to ask if extraordinary June heat is the 鈥渘ew normal鈥�. Unfortunately, the truth is that we are never going to have normal in our lifetimes again 鈥� just ever more extreme heat.

Climate scientists are continually warning of the need to prepare for hotter heatwaves, worse droughts, more flooding and rising seas. During heatwaves like the one just passed, the hottest and most humid ever seen in Europe, they might even get a little media coverage. But then the weather cools, the news agenda moves on and nothing is ever done.

We are currently on course for average global surface temperatures to rise by between 2.1掳C and 3.3掳C by 2100, and possibly even more. Even these alarming numbers are a little misleading because the oceans that cover most of the planet don鈥檛 warm as fast as the land. Average land temperatures are therefore going to go up by a lot more than the above numbers imply.

But what really matters to us is extreme weather, not the average. The projections for future extremes are already dire, and there are reasons to think that we are in for extremes even greater than those currently projected for a given level of warming. With uncertainties over the survival of the vital AMOC ocean current and the risk of a major glacier collapse, the only thing we really do know is that we must prepare for conditions far worse than Europe has just experienced.

We are on course for average global surface temperatures to rise by between 2.1掳C and 3.3掳C

It is possible to get through even worse heatwaves if all your infrastructure and systems are geared up to cope, but for most countries, this isn鈥檛 the case. The fact is, the world is changing fast and we need to change just about every aspect of our lives to adapt 鈥� our homes and offices, factories and schools, cars and trains, farms and gardens, and so on. But it isn鈥檛 happening. One day, after the tragic deaths grow too great to bear, we will ask why we did nothing to prevent them.

Know your onions

Tidy-up time

Think of the children

Our brains love shortcuts. Decisions are often made via a subconscious muddling through, due to the . It is perhaps why we value neat categorisations of someone鈥檚 brain state, despite these being flawed.

Take the age at which you become an adult. Around the world, legal adulthood varies from 16 to 21. This difference matters, as we rightly have different expectations for children versus adults. Some call for this tension to be smoothed by asking policy-makers to consider typical brain maturity levels, ascertained via tools like brain imaging, in matters like criminal sentencing or the right to drive. The idea that our brains don鈥檛 fully develop until we are 25 is also becoming popular, but 鈥� as we discuss in our special on brain changes 鈥� this is wrong. Brains mature at different rates and there are myriad ways to measure their development.

This isn鈥檛 the only way neuroscience is looked to for informing policy before the science is ready. Take autism, which may come in several distinct types. A recently proposed category of 鈥減rofound autism鈥� could identify those with the highest needs, by assessing IQ, language skills and care requirements. This could assist in advocating for services for people in this group, but may exclude those who don鈥檛 meet strict criteria. It could also people with speech difficulties with people with cognitive impairments 鈥� different neurological profiles demanding different help.

Neuroscience is looked to for informing policy before the science is ready

Attempts to use psychological profiling in courts, too, are worrying. When presented as a mitigating factor in some cases, , taking a slam-dunk prosecution down a messier road. But . shows that, while potentially legally relevant, it can鈥檛 be used with confidence.

Our wish to put brains into tidy boxes is natural, and a future in which neuroscience can help us put a fine point on someone鈥檚 cognitive state could well be possible. That future, though, is not yet here.

Big lizard, big page

Orwell strikes again

Dog ate my homework

For years, we have had unconfirmed reports and rumours that AI-controlled weapons have killed soldiers on the battlefield without a human in the loop. Now, we know it has happened.

As we report here, the use of autonomous killers in a test exercise marks a watershed in warfare. But we shouldn鈥檛 be surprised. The technology has existed for some time and humans have never invented a weapon and then refrained from using it.

That doesn鈥檛 mean we can鈥檛 reverse course. The logic for a ban on autonomous weapons is simple: deploying AI without human oversight risks weapons accidentally targeting troops on the wrong side or even civilians. What鈥檚 more, ethicists say that such weapons deprive combatants of their dignity, make war too easy to wage and muddy the waters when it comes to responsibility for lethal action.

But if we are to ban these weapons, just as we have done with cluster bombs and lasers designed to blind soldiers, we should have acted before they arrived, not after. The United Nations has been in talks to ban fully autonomous weapons for over a decade, but according to the Human Rights Watch campaign group, India, Israel, Russia and the US have vetoed the discussions.

Humans have never invented a weapon and then refrained from using it

The framework to ban autonomous weapons already exists 鈥� they could easily be added to the list of excessively injurious or indiscriminate arms proscribed by the UN Convention on Certain Conventional Weapons. More difficult to reckon with is the fact that these drones can be made with inexpensive parts ordered online and some open-source software. Any
tech-literate teenager could do it.

As we explore here, the war in Ukraine has made it clear that robots will dominate future battlefields. The question the world must now answer is whether a human should always be involved, ultimately responsible for the decision to pull the trigger, or whether machines can be allowed to act alone. Whichever we choose, a decision must be made before the technology proliferates.

Funny feeling

Satan versus gravity

Waymo out of line

Maverick scientists often get a bad reputation among their more sober peers. Science requires evidence and consensus, and contrarianism is rarely a way forward.

But there is always an exception that proves the rule. Take the idea that the ketogenic diet 鈥� a restrictive regime most famous as a way to rapidly lose weight 鈥� could be a treatment for anorexia nervosa. Given that this is a psychiatric condition characterised by a compulsion to restrict food, the proposal sounds absurd at best, painfully irresponsible at worst.

We should take this counterintuitive idea seriously, however. As we learn in this week鈥檚 cover story, following the diet does seem to help people with the condition, albeit only in a small study. It is thought to be a result of keto correcting haywire energy release in brain cells, thereby cutting anxiety and, with it, the compulsion to restrict food. If nothing else, this is a sign that keto should be studied as a potential anorexia treatment. At present, one-third of those with the condition don鈥檛 recover from standard treatment, and anorexia has the highest mortality rate of any psychiatric condition.

It is a mistake to think an idea is bad simply because people who have bad ideas support it

Unfortunately, supporting keto as a treatment for serious mental health conditions aligns one with people such as Robert F. Kennedy Jr, the controversial US health secretary. When it comes to health advice, you can鈥檛 get much more maverick than a man who claims, without evidence, that vaccines cause autism.

But it is a mistake to think that an idea is bad simply because people who generally have bad ideas support it. Multiple lines of evidence point towards keto鈥檚 mental health benefits 鈥� as we set out in our 2 May cover story, it seems to hold promise for blunting the symptoms of conditions from severe depression to schizophrenia. Given the research is at an early stage, the diet should be used for anorexia only under medical supervision, as much larger trials are needed. But seeking solutions to debilitating conditions via careful science is vital, even if doing so carries the risk of initially being labelled absurd, irresponsible or maverick.