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Katie Steckles enlists the help of fluid dynamics researcher Kat Phillips to explain the versatile piece of maths behind dispensing wine from a box

Cyborg: A documentary tells the intriguing story of Neil Harbisson, who wears an antenna to “hear” colour, but it is lacking in depth and should have probed its subject more, says Simon Ings

The books, TV, games and more that New Scientist staff have enjoyed this week

This claustrophobia-inducing image is taken from photographer Martin Broen's new book Light in the Underworld, a collection of shots from the Yucatán’s cenotes, or sinkholes

What is it like to be a dog? And what can we learn from them? Mark Rowlands's take, in his book The Happiness of Dogs, is full of insights, finds Abigail Beall

Our Future Chronicles column explores an imagined history of inventions and developments yet to come. This time, Rowan Hooper takes us to the early 2030s, when a technological step change enabled us to produce all the food we needed without the use of animals

From serpents to zombie pathogens, there is science behind our love of monsters. It reveals a lot about who we are, says Natalie Lawrence

Supremacy, a new book from tech journalist Parmy Olson, takes us inside the rise of machine learning and AI, and examines the people behind it

Far from being a behavioural quirk, obsessive-compulsive disorder is a debilitating condition with complex causes that we're just beginning to understand. We should treat it as such, and stop with the misguided quips

In this short video, Rear Admiral Daniel Hagari, chief spokesman for the IDF, shows us the conditions under which the six recently-murdered hostages were kept. (Trigger warning: blood.) For some reason I thought the hostages were being kept either in private residences or in rooms off the tunnels, not in the tunnels themselves. When you realize how many days these hostages have been sequestered by Hamas, even a few days of these conditions seem unbearable.  Clearly the IDF has already done DNA analysis of the blood and will do so on hair from hairbushes.

The conditions under which Israel keeps Palestinian prisoners, including convicted terrorists, are far, far better than the conditions under which Hamas keeps its hostages. Palestinian prisoners in Israel live in sheer luxury compared to what you see below, with food they can cook themselves, fresh air, and good beds.

Remember too that there are still about 60 living hostages in Gaza.  They should be released unconditionally—no deals, no bargaining.  Of course Hamas won’t do it, but in my view making a deal for the hostages by releasing Palestinian terrorists is a bad business.  Right now the world should be baying not for a cease-fire or a deal, but for Hamas to surrender unconditionally and release the hostages, or the IDF has the right to, and will, continue going after the enemy.

Here is a question that keeps me awake at nights: how do you define right versus left without referring to something, like the placement of our heart, an organ that is already tilted toward one side of the body (the left except in rare cases of situs inversus)?

For example, have a look at a bilaterally symmetrical organism below, in this case one of my favorites (Merriam-Webster defines bilateral symmetry as “symmetry in which similar anatomical parts are arranged on opposite sides of a median axis so that only one plane can divide the individual into essentially identical halves”.) We know left from right because we define them consistently, and that’s because humans are NOT bilaterally symmetrical so we can all agree on which side is which.

But now I’ll ask you to answer this. (i.e., by pointing) Assume you’re talking to a person (a Martian?) who has never heard about right vs. left sides.  Tell them, using the diagram of one of my favorite organisms below, standing upright, which side is the right and which the left without referring to your own body, to any minute differences in the diagram, or to asymmetries in the environment (e.g. the world or the solar system).  Since both sides are identical, how do you know which one is right without referring to how we’ve already defined it, presumably based on our own bodies?  Explain to a Martian who is bilaterally symmetrical which side is its right and which its left, and how they would know it.

Partial image by Charl Hutchings, CC BY 4.0, via Wikimedia Commons

 

I’m not sure if I’m making myself clear here, so I looked in the Oxford English Dictyion for the definition of “right”. There are of course many definitions that don’t refer to the direction, but here’s what it gives for the direction:

a.  of, relating to, situated on, or being the side of the body which is away from the side on which the heart is mostly located b.  located nearer to the right hand than to the left c. located to the right of an observer facing the object specified or directed as the right arm would point when raised out to the side d. located on the right of an observer facing in the same direction as the object specified

This didn’t help, because it all comes down to how humans have defined the sides based on our own asymmetries.

This problem is connected with something that’s always intrigued me: how do directional asymmetries evolve, in which an animals is predictably asymmetrical, like our hearts being more on one side or the others?  (There are some creatures with “fluctuating asymmetry”, in which right is different from left, but it’s not consistent, like lobsters in which one claw is a crusher and the other a slicer, or flatfish that develop to lie randomly on its left or right side sides as adults.  Evolving these doesn’t pose the problem I describe below.)

If we evolved from a bilaterally symmetrical (or radially symmetrical) organism, then even if front and back are genetically specified, as they are, how can you evolve from such a creature into an organism that has features consistently on the right (or left) sides?  The chemical gradients in a bilaterally symmetrical ancestor are presumably the same on both sides, so how can a gene mutation arise that consistently recognizes a given side to give rise to a feature on that side? In other words, how can a mutation KNOW whether it is on the left or right side of the body? (Of course once an initial directional asymmetry has evolved, it creates a directional cue that can be used to evolve further directional asymmetries. It’s the evolution of the first directional feature that is the difficulty.)

I’ve discussed this more clearly in two old posts on this site (here and here), which gives some partial answers residing in how asymmetrical molecules or asymmetrical beating of cilia could lead to the evolution of directional asymmetry from bilateral asymmetry.

But the problem above still nags at me: how do you tell a bilaterally symmetrical Martian which side is right and which is left without referring to our own bodies? Can it be done?

Again, this may be a non-problem, but I’ve seen no definition of “right” or “left” independent of our own bodily asymmetries.

Analysis of DNA from a Neanderthal fossil found in a French cave indicates that it belonged to a group that was isolated for more than 50,000 years

DNA analysis shows that people from Easter Island had contact with Indigenous Americans around the 1300s, and finds there was no population crash before the arrival of Europeans

Gas bubbles on the surface of a star have been observed for the first time in detail outside our solar system, and they are 75 times the size of our sun

We're finally pinning down the mechanisms that drive obsessive-compulsive disorder, revealing a complex combination of imbalanced brain networks, the immune system and even gut microbes

Physicists have created the first two-dimensional version of the Bose glass, a novel phase of matter that challenges statistical mechanics.

Researchers have succeeded in combining two major research fields in photonics by creating a nano-object with unique optical qualities. Since the object is a thousand times thinner than the human hair, yet very powerful, the breakthrough has great potential in the development of efficient and compact nonlinear optical devices.

Researchers have succeeded in combining two major research fields in photonics by creating a nano-object with unique optical qualities. Since the object is a thousand times thinner than the human hair, yet very powerful, the breakthrough has great potential in the development of efficient and compact nonlinear optical devices.

For the design of reliable power grounding systems for critical electrical infrastructure, soil resistivity investigation is crucial. However, soil resistivity depends on various geotechnical properties, necessitating the need for robust assessment methods. In a new study, researchers conducted a comprehensive investigation into the behavior and relationships between soil resistivity and key geotechnical parameters and developed a predictive model based on their findings. This model can lead to cost-effective and more reliable design of grounding systems.

Water polluted with heavy metals can pose a threat when consumed by humans and aquatic life. Sugar-derived polymers from plants remove these metals but often require other substances to adjust their stability or solubility in water. Now, researchers report a sugar-like polymer that traps heavy metals within insoluble clumps for easy removal. In proof-of-concept tests, the polymer removed ionic cadmium and lead from river water spiked with these persistent contaminants.