Science

Scientists detected the first long-predicted gravitational wave in 2015, and since then, researchers have been hungering for better detectors. But the Earth is warm and seismically noisy, and that will always limit the effectiveness of Earth-based detectors.

Is the Moon the right place for a new gravitational wave observatory? It might be. Sending telescopes into space worked well, and mounting a GW observatory on the Moon might, too, though the proposal is obviously very complex.

Most of astronomy is about light. The better we can sense it, the more we learn about nature. That’s why telescopes like the Hubble and the JWST are in space. Earth’s atmosphere distorts telescope images and even blocks some light, like infrared. Space telescopes get around both of those problems and have revolutionized astronomy.

Gravitational waves aren’t light, but sensing them still requires extreme sensitivity. Just as Earth’s atmosphere can introduce ‘noise’ into telescope observations, so can Earth’s seismic activity cause problems for gravitational wave detectors. The Moon has a big advantage over our dynamic, ever-changing planet: it has far less seismic activity.

We’ve known since the Apollo days that the Moon has seismic activity. But unlike Earth, most of its activity is related to tidal forces and tiny meteorite strikes. Most of its seismic activity is also weaker and much deeper than Earth’s. That’s attracted the attention of researchers developing the Lunar Gravitational-wave Antenna (LGWA).

The developers of the LGWA have written a new paper, “The Lunar Gravitational-wave Antenna: Mission Studies and Science Case.” The lead author is Parameswaran Ajith, a physicist/astrophysicist from the International Centre for Theoretical Science, Tata Institute of Fundamental Research, Bangalore, India. Ajith is also a member of the LIGO Scientific Collaboration.

A gravitational wave observatory (GWO) on the Moon would cover a gap in frequency coverage.

“Given the size of the Moon and the expected noise produced by the lunar seismic background, the LGWA would be able to observe GWs from about 1 mHz to 1 Hz,” the authors write. “This would make the LGWA the missing link between space-borne detectors like LISA with peak sensitivities around a few millihertz and proposed future terrestrial detectors like Einstein Telescope or Cosmic Explorer.”

If built, the LGWA would consist of a planetary-scale array of detectors. The Moon’s unique conditions will enable the LGWA to open a larger window into gravitational wave science. The Moon has extremely low background seismic activity that the authors describe as ‘seismic silence.’ The lack of background noise will enable more sensitive detections.

The Moon also has extremely low temperatures inside its permanently shadowed regions (PSRs.) Detectors must be super-cooled, and the cold temperatures in the PSRs make that task easier. The LGWA would consist of four detectors in a PSR crater at one of the lunar poles.

This schematic shows one of the LGWA’s detectors on the floor of a lunar PSR. Image Credit: LGWA

The LGWA is an ambitious idea with a potentially game-changing scientific payoff. When combined with telescopes observing across the electromagnetic spectrum and with neutrino and cosmic ray detectors—called multi-messenger astronomy—it could advance our understanding of a whole host of cosmic events.

The LGWA will have some unique capabilities for detecting cosmic explosions. “Only LGWA can observe astrophysical events that involve WDs (white dwarfs) like tidal disruption events (TDEs) and SNe Ia,” the authors explain. They also point out that only the LGWA will be able to warn astronomers weeks or even months in advance of solar mass compact binaries, including neutron stars, merging.

The LGWA will also be able to detect lighter intermediate-mass black hole (IMBH) binaries in the early Universe. IMBHs played a role in forming today’s supermassive black holes (SMBHs) at the heart of galaxies like our own. Astrophysicists have a lot of unanswered questions around black holes and how they’ve evolved and the LGWA should help answer some of them.

Double White Dwarf (DWD) mergers outside our galaxy are another thing that the LGWA alone will be able to sense. They can be used to measure the Hubble Constant. Over the decades, scientists have gotten more refined measurements of the Hubble constant, but there are still discrepancies.

A graphical summary of the LGWA science case, including multi-messenger studies with electromagnetic observatories and multiband observations with space-borne and terrestrial GW detectors. Image Credit: Ajith et al. 2024/LGWA

The LGWA will also tell us more about the Moon. Its seismic observations will reveal the Moon’s internal structure in more detail than ever. There’s a lot scientists still don’t know about its formation, history, and evolution. The LGWA’s seismic observations will also illuminate the Moon’s geological processes.

The LGWA mission is still being developed. Before it can be implemented, scientists need to know more about where they plan to place it. That’s where the preliminary Soundcheck mission comes in.

In 2023, the ESA selected Soundcheck into its Reserve Pool of Science Activities for the Moon. Soundcheck will not only measure seismic surface displacement, magnetic fluctuations and temperature, it will also be a technology demonstration mission. “The Soundcheck technology validation focuses on deployment, inertial sensor mechanics and readout, thermal management and platform levelling,” the authors explain.

This schematic shows one of the Soundcheck seismic stations. Image Credit: LGWA

In astronomy, astrophysics, cosmology, and related scientific endeavours, it always seems like we’re on the precipice of new discoveries and a new understanding of the Universe and how we fit into it. The reason it always seems like that is because it’s true. Humans are getting better and better at it, and the advent and flourishing of GW science exemplifies that, even though we’re just getting started. Not even a decade has passed since scientists detected their first GW.

Where will things go from here?

“Despite this well-developed roadmap for GW science, it is important to realize that the exploration of our Universe through GWs is still in its infancy,” the authors write in their paper. “In addition to the
immense impact expected on astrophysics and cosmology, this field holds a high probability for unexpected and fundamental discoveries.”

The post Here’s Why We Should Put a Gravitational Wave Observatory on the Moon appeared first on Universe Today.

Two papers look at the effects of cold water immersion after exercise, with mixed results.

The post Cold Water Immersion Not Always Beneficial first appeared on Science-Based Medicine.

In recent talks at physics departments about my book, I have emphasized that the elementary “particles” of nature — electrons, photons, quarks and so on — are really little waves (or, to borrow a term that was suggested by Sir Arthur Eddington in the 1920s, “wavicles”.) But this notion inevitably generates confusion. That’s because of another wavy concept that arises in “quantum mechanics” —the quantum physics of the 1920s, taught to every physics student. That concept is Erwin Schrödinger’s famous “wave function”.

It’s natural to guess that wave functions and wavicles are roughly the same. In fact, however, they are generally unrelated.

Wavicles Versus Wave Functions

Before quantum physics came along, field theory was already used to predict the behavior of ordinary waves in ordinary settings. Field theory is useful for sound waves in air, seismic waves in rock, and waves on water.

Quantum field theory, the quantum physics that arose out of the 1940s and 1950s, adds something new: it tells us that waves in quantum fields are made from wavicles, the gentlest possible waves. A photon, for instance, is a wavicle of light — the dimmest possible flash of light.

By contrast, a wave function describes a system of objects operating according to quantum physics. Importantly, it’s not one wave function per object — it’s one wave function per system of interacting objects. That’s true whether the objects in the system are particles in motion, or something as simple as particles that cannot move, or something as complex as fields and their wavicles.

One of the points I like to make, to draw the distinction between these two types of waves in quantum physics, is this:

• Wavicles can hurt you.
• Wave functions cannot.

Daniel Whiteson, the well-known Large Hadron Collider physicist, podcaster and popular science writer, liked this phrasing so much that he quoted the second half on X/Twitter. Immediately there were protests. One person wrote “Everything that has ever hurt anyone was in truth a wave function.” Another posted a video of an unfortunate incident involving the collision between a baseball and a batter, and said: “the wave function of this baseball disagrees.”

It’s completely understandable why there’s widespread muddlement about this. We have two classes of waves floating around in quantum physics, and both of them are inherently confusing. My aim today is to make it clear why a wave function couldn’t hurt a fly, a cat, or even a particle.

The Basic Concepts

Wavicles, such as photons or electrons, are real objects. X-rays are a form of light, and are made of photons — wavicles of light. A strong beam of X-ray photons can hurt you. The photons travel across three-dimensional space carrying energy and momentum; they can strike your body, damage your DNA, and thereby cause you to develop cancer.

The wave function associated with the X-ray beam, however, is not an object. All it does is describe the beam and its possible futures. It tells us what the beam’s energy may be, but it doesn’t have any energy, and cannot inflict the beam’s energy on anything else. The wave function tells us where the beam may go, but itself goes nowhere. Though it describes a beam as it crosses ordinary three-dimensional space, the wave function does not itself exist in three-dimensional space.

In fact, if the X-ray beam is interacting with your body, then the X-ray beam cannot be said to have its own wave function. Instead, there is only one wave function — one that describes the beam of photons, your atoms, and the interactions between your atoms and the photons.

More generally, if a bunch of objects interact with each other,the multiple interacting objects form a single indivisible system, and a single wave function must describe it. The individual objects do not have separate wave functions.

Schrödinger’s Cat

This point is already illustrated by Schrödinger’s famous (albeit unrealistic) example of the cat in a box that is both dead and alive. The box contains a radioactive atom which will, via a quantum process, eventually “decay” [i.e. transform itself into a new type of atom, releasing a subatomic particle in the process], but may or may not have done so yet. If and when the atom does decay, it triggers the poisoning of the cat. The cat’s survival or demise thus depends on a quantum effect, and it becomes a party to a quantum phenomenon.

It would be a mistake to say that “the atom has a wave function” (or even worse, that “the atom is a wave function”) and that this wave function can kill the cat. To do so would miss Schrödinger’s point. Instead, the wave function includes the atom, the killing device, and the cat.

Initially, when the box is closed, the three are independent of one another, and so they have a relatively simple wave function which one may crudely sketch as

• Wave Function = (atom undecayed) x (device off) x (cat alive)

This wave function represents our certainty that the atom has not yet decayed, the murder weapon has not been triggered, and the cat is still alive.

But this initial wave function immediately begins evolving into a more complicated form, one which depends on two time-varying complex numbers C and D, with |C|2 + |D|2 = 1:

• Wave Function = C(t) x (atom undecayed) x (device off) x (cat alive) + D(t) x (atom decayed) x (device on) x (cat dead)

The wave function is now a sum of two “branches” which describe two distinct possibilities, and assigns them probabilities |C|2 and |D|2, the former gradually decreasing and the latter gradually increasing. [Note these two branches are added together in the wave function; its branches cannot be rearranged into wave functions for the atom, device and cat separately, nor can the two branches ever be separated from one another.]

In no sense has the wave function killed the cat; in one of its branches the cat is dead, but the other branch describes a live cat. And in no sense did the “wave function of the atom” or “of the device” kill the cat, because no such wave functions are well-defined in this interacting system.

A More Explicit Example

Let’s now look at an example, similar to the cat but more concrete, and easier to think about and draw.

Let’s take two particles [not wavicles] A and B. These particles travel only in a one-dimensional line, instead of in three-dimensional space.

Initially, particle B is roughly stationary and particle A comes flying toward it. There are two possible outcomes.

• There is a 30% probability that A passes right by B without affecting it, in which case B simply says “hi” as A goes by.
• There is a 70% probability that A strikes B head-on and bounces off of it, in which case B, recoiling from the blow, says “ow”.

In the second case, we may indeed say that A “hurts” B — at least in the sense of causing B to recoil suddenly.

The Classical Probabilities

Before we answer quantum questions, let’s first think about how one might describe this situation in a world without quantum physics. There are several ways of depicting what may happen.

Motion in One-Dimensional Physical Space

We could describe how the particles move within their one-dimensional universe, using arrows to illustrate their motions over time. In the figure below, I show both the “hi” possibility and the “ow” possibility.

Figure 1: (Top) With 30% probability, the Hi case: A (in blue) passes by B without interacting with it. (Bottom) With 70% probability, the Ow case: A strikes B, following which A rebounds and B recoils.

Or, using an animation, we can show the time-dependence more explicitly and more clearly. In the second case, I’ve assumed that B has more mass than A, so it recoils more slowly from the blow than does A.

Figure 2: Animation of Fig. 1, showing the Hi case in which A passes B, and the Ow case where A strikes B. Motion in the Two-Dimensional Space of Possibilities

But we could also describe how the particles move as a system in their two-dimensional space of possibilities. Each point in that space tells us both where A is and where B is; the point’s location along the horizontal axis gives A’s position, and its location along the vertical axis gives B’s position. At each moment, the system is at one point in that space; over time, as A and B change their positions, the location of the system in that two-dimensional space also changes.

The motion of the system for the Hi and Ow cases is shown in Fig. 3. It has exactly the same information as Fig. 1, though depicted differently and somewhat more precisely. Instead of following the two dots that correspond to the two particles as they move in one dimension, we now depict the whole system as a single diamond that tells us where both particles are located.

In the first part of Fig. 3, we see that B’s position is at the center of the space, and remains there, while A’s position goes from the far right to the far left; compare to Fig. 1. In the second part of Fig. 3, A and B collide at the center, following which A moves to positive position, B moves to negative position, and correspondingly, within its space of possibilities, the system as a whole moves down and to the right.

Figure 3: How the A/B system moves through the space of possibilities. (Top) In the Hi case, A moves while B remains fixed at its central position. (Botttom) The Ow case is the same as the Hi case until A’s position reaches B’s position at the center; a collision then causes A to reverse course to a positive position, while B is driven to a negative position (which is downward in this graph.) The system as a whole thus moves down and to the right in the space of possibilities.

And finally, let’s look at an animation in the two-dimensional space of possibilities. Compare this to Fig. 3, and then to Fig. 2, noting that it has the same information.

Figure 4: Animation of Figure 3, showing (top) the Hi case in which A passes B and (bottom) the Ow case where A strikes B.

In Fig. 4, we see that

• the system as a whole is represented as a single moving point in the space of possibilities
• each of the two futures for the system are represented as separate time-dependent paths across the space of possibilities

The Quantum System

Now, what if the system is described using quantum physics? What’s up with the system’s wave function?

As noted, we do not have a wave function for particle A and a separate wave function for particle B, and so we do not have a collision of two wave functions. Instead, we have a single wave function for the A/B system, one which describes the collision of the two particles and the aftermath thereof.

It is impossible to depict the wave function using the one-dimensional universe that the particles live in. The wave function itself only exists in the space of possibilities. So in quantum physics, there are no analogues to Figs. 1 and 2.

Meanwhile, although we can depict the wave function at any one moment in the two dimensional space, we cannot simply use arrows to depict how it changes over time. This is because we cannot view the “Hi” and “Ow” cases as distinct, and as something we can draw in two separate figures, as we did in Figs. 3 and 4. In quantum physics, we have to view both possibilities as described by the same wave function; they are not distinct outcomes.

The only option we have is to do an animation in the two-dimensional space of possibilities, somewhat similar to Fig. 4, but without separating the Hi and Ow outcomes. There’s just one wave function that shows both the “Hi” and “Ow” cases together. The square of this wave function, which gives the probabilities for the system’s possible futures, is sketched in Fig. 5.

[Note that what is shown is merely a sketch! It is not the true wave function, which requires a complete solution of Schrödinger’s wave equation. While the solution is well known, it is tricky to get all the details of the math exactly right, and I haven’t had the time. I’ll try to add the complete and correct solution at a later date.]

Compare Fig. 5 with Fig. 4, recalling that the probability of the Hi case is 30% and the probability of the Ow case is 70%. Both possibilities appear in the wave function, with the branch corresponding to the Ow case carrying larger weight than the branch corresponding to the Hi case.

Figure 5: A rough sketch of what the square of the wave function of the A/B system looks like; small-scale details are not modeled correctly. Note both Hi and Ow possibilities, and their relative probabilities, appear in the wave function. Compare with Fig. 4 and with the example of Schrödinger’s cat.

In contrast to Fig. 4, the key differences are that

• the system is no longer represented as a point in the space of possibilities, but instead as a (broadened) set of possibilities
• the wave function is complicated during the collision, and develops two distinct branches only after the collision
• all possible futures for the system exist within the same wave function
  • this has the consequence that distinct future possibilities of the system could potentially affect each other at a later time — a concept which makes no sense in non-quantum physics
• the probabilities of those distinct futures are given by the relative sizes of the wave function within the two branches.

Notice that even though particle A has a 70% probability of “hurting” B, the wave function itself does not, and cannot, “hurt” B. It just describes what may happen; it contains both A and B, and describes both the possibility of Hi and Ow. The wave function isn’t a part of the A/B system, and doesn’t participate in its activities. Instead, it exists outside the system, as a means for understanding that system’s behavior.

Summing Up

A system has a wave function, but individual objects in the system do not have wave functions. That’s the key point.

To be fair, it is true that when objects or groups of objects in a system interact weakly enough, we may imagine the system’s full wave function as though it were a simple combination of wave functions for each object or group of objects. That is true of the initial Schrödinger cat wave function, which is a product of separate factors for the atom, device and cat, and is also true of the wave function in Fig. 5 before the collision of A and B. But once significant interactions occur, this is no longer the case, as we see in the later-stage Schrödinger cat wave function and in Fig. 5 after the collision.

A wave function expresses how the overall system moves through the full space of its possibilities, and grows ever more complex when there are many possible paths for a system to take. This is completely unrelated to wavicles, which are objects that move through physical space and create physical phenomena, forming parts of a system that itself is described by a wave function.

A Final Note on Wave Functions

As a final comment: I’ve given this simple example because it’s one of the very few that one can draw start to finish.

Wave functions of systems with just one particle are misleading, because they make it easy to imagine that there is one wave function per particle. But with more than one particle, the only wave functions that can easily be depicted are those of two particles moving in one dimension, such as the one I have given you. Such examples offer a unique opportunity to clarify what a wave function is and isn’t, and it’s therefore crucial to appreciate them.

Any wave function more complicated than this becomes impossible to draw. Here are some things to consider.

• I have only drawn the square of the wave function in Fig. 5. The full wave function is a complex function (i.e. a complex number at each point in the space of possibilities), and the contour plot I have used in Fig. 5 could only be used to draw its real part, its imaginary part, or its square. Thus even in this simple situation with a two-dimensional space of possibilities, the full wave function cannot easily be represented.
• If we had four particles moving in one dimension instead of two, with positions x1, x2, x3 and x4 respectively, then the wave function would be a function of the four-dimensional space of possibilities, with coordinates x1, x2, x3, x4 . [The square of the wave function at each point in that space tells us the probability that particle 1 is at position x1, particle 2 is at position x2, and similarly for 3 and 4.] A function in four dimensions can be handled using math, but is impossible to draw.
• If we had two particles moving in three dimensions, the first with position x1, y1, z1, and the second with position x2, y2, z2, the space of possibilities would be six-dimensional — x1, y1, z1, x2, y2, z2 . Again, this cannot be drawn.

These difficulties explain why one almost never sees a proper discussion of wave functions of complicated systems, and why wave functions of fields are almost never described and are never depicted.

Well over 5,000 planets have been found orbiting other star systems. One of the satellites hunting for them is TESS, the Transiting Exoplanet Survey Satellite. Astronomers using TESS think they are made a rather surprising discovery; their first free-floating – or rogue – planet. The planet was discovered using gravitational microlensing where the planet passed in front of a star, distorting its light and revealing its presence.

We are all familiar with the eight planets in our Solar System and perhaps becoming familiar with the concept of exoplanets. But there is another category of planet, the rogue planets. These mysterious objects travel through space without being gravitationally bound to any star. Their origin has been cause for much debate but popular theory suggests they were ejected from their host star system during formation, or perhaps later due to gravitational interaction. 

Artist impression of glory on exoplanet WASP-76b. Credit: ESA

Simulations have suggested that these ‘free-floating planets’ or FFPs should be abundant in the Galaxy yet until now, not many have been detected. The popular theory of ejection from star systems may not be the full story though. It is now thought that different formation mechanisms will be responsible for different FFP masses. Those FFPs that are high mass may form in isolation from the collapse of gas whilst those at the low mass end (comparable to Earth) are likely to have been subjected to gravitational ejection from the system. A paper published in 2023 even suggests that those FFPs are likely to outnumber those bound planets across the Galaxy!

Detecting such wandering objects among the stars is rather more of a challenge than you might expect. Their limited emission (or reflection) of electromagnetic radiation makes them pretty much impossible to observe. Enter gravitational microlensing, a technique that relies upon an FFP passing in front of a star, it’s gravity then focussing light from the distant star resulting in a brief brightness change as the planet moves along its line of sight. To date, only three FFPs have been detected from Earth using this technique. 

A team of astronomers have been using TESS to search for such microlensing events. TESS was launched in April 2018 and whilst in orbit, scans large chunks of sky to monitor the brightness of tens of thousands of stars. The detection of light changes may reveal the passage of an FFP as it drifts silently in front of the star. It’s not an easy hunt though as asteroids in our Solar System, exoplanets bound to stars and even stellar flares can all give false indications but thankfully the team led by Michelle Kunimoto have algorithms that will help to identify potential targets. 

Illustration of NASA’s Transiting Exoplanet Survey Satellite. Credit: NASA’s Goddard Space Flight Center

The team published their findings recently in the Astrophysical Journal and reported one FFP candidate event associated with the star TIC-107150013 which is 3.2 parsec away. The event lasted 0.074 days +/- 0,002 and revealed a light curve with features expected of a FFP. This marks the first FFP discovered by TESS, an exciting step along the way to start to unravel the mysteries surrounding these strange alien worlds.

Source : Searching for Free-Floating Planets with TESS: I. Discovery of a First Terrestrial-Mass Candidate

The post TESS Finds its First Rogue Planet appeared first on Universe Today.

Scientists are using artificial intelligence software to analyze plant root systems, laying out a protocol that can be applied to gather data on crop and model plant phenotypes (physical characteristics) more efficiently and with equal or greater accuracy than existing methods.

Researchers discovered that light can cause evaporation of water from a surface without the need for heat. This 'photomolecular effect' could be important for understanding climate change and for improving some industrial processes.

A new survey has found that for residents living within three miles of a large-scale solar development, positive attitudes outnumbered negative attitudes by almost a 3-to-1 margin. Researchers surveyed almost 1,000 residents living near solar projects.

Almost all moon landers break down during the extraordinary cold of lunar night, but Japan’s Smart Lander for Investigating Moon has astonishingly survived three nights

The very weak forces of attraction caused by the Casimir effect can now be used to manipulate microscopic gold flakes and turn them into a light-trapping tool

Targeted culling of crown-of-thorns starfish has resulted in parts of the Great Barrier Reef maintaining and even increasing coral cover, leading researchers to call for the programme to be dramatically scaled up

An anonymous author (presumably Canadian) has written this piece for Times Higher Education, and it’s clear why he or she doesn’t want their name given. If that was publicized, the person would never be able to get any academic job in Canada.  Below are the two job ads from the University of Waterloo to which the anonymous author objects (click to find them). Note that there are two positions in computer science, but both reserved for those who self-identify as “minoritized” people, including Two-spirit people. What are those? The U.S. Indian Health Service defines them this way:

Traditionally, Native American two-spirit people were male, female, and sometimes intersexed individuals who combined activities of both men and women with traits unique to their status as two-spirit people. In most tribes, they were considered neither men nor women; they occupied a distinct, alternative gender status.

I had thought these were simply indigenous people, but they seem to be non-binary indigenous people. So the first position is for people whose sexual identity doesn’t conform to their natal sex (I assumed that “identify as women” meant transwomen, but since “trangender” follows that, it could mean natal females as well. And the other job is for a minority, but a “racialized” minority, which means “not women”and nobody white”. I’m not sure whether Asians count as “members of a racialized minority.”  They are in a minority, and they are thought of as a race, so perhaps they would be. Canadians can weigh in here.

Regardless of how you interpret the requirements, it’s clear that these ads are targeted only for “minoritized” individuals. (Women in computer science stubbornly remain a minority, perhaps not because of structural sexism).

 

And here’s the anonymous article (click to read):

The author wants to apply for these jobs but since he or she (I’m guessing it’s a “he” since women could apply for the first job) simply isn’t qualified.  Excerpts:

The intention behind these postings is not malicious; rather, it aims to correct historical injustices. The attempted correction, however, only adds to the injustice of discrimination.

Why is academia so equivocal about making a universal condemnation of discrimination?

The author gives three reasons. First, the ad implicitly aims to correct bias, but underrepresentation of groups in a field, as you should know well know by now, need not automatically imply systemic bias. As the author says, it could reflect “differences in sex or culture” that “influence interests, behaviours or priorities.” I am pretty sure this plays a role in the underrepresentaiton of women in computer science.

Second, such ads, by assuming that the oppression reflects a hierarchy of bigotry, “perpetuates the false and dangerous idea that scars are passed down through generations, as if modern-day French children should cultivate hatred towards Germans because of the world wars.” He/she believes that the ads perpetrate a view of society as an eternal power struggle à la postmodernism. Well, that may be partly correct if underrepresentation reflects lower qualifications based on historical discrimination, but one can still wonder whether that should be rectified by ads like these, which list identity as the first criterion for application (presumably merit will be considered later).

Third, the author claims that “debate is stifled.”  I’m not sure what that means, but presumably the mere appearance of these ads justifies discriminatory hiring. As the author notes,

While intellectual and cultural diversity enriches humanity, equality in dignity unites us in a spirit of fraternity. Discrimination violates this moral equality, fosters resentment, undermines social cohesion, instrumentalises individuals and conveys the fatalistic and wrong idea that one’s path is determined by one’s ethnicity or gender. These severe consequences are wishfully thought to be dodged when discrimination is given a different name. But they are not.

Finally, the author tacks on another problem: those who are hired may be under the self-stigma of realizing that they got their job because of racial or sexual identity, not because of merit. This fact is of course the case for many minority hires, but I’m not sure if those hires are constantly tormented with this kind of self-doubt, though I know from testimony that some are. The author favors a “colorblind” approach to hiring, i.e., prize merit over identity.

I agree that the ads are objectionable, and they’d be illegal in the United States. Still, I favor a form of affirmative action, which is gradually taking shape as a belief that when candidates are pretty equally qualified, you can hire (or admit) the minority candidate more than half the time.  But even that is now illegal in the U.S., though of course schools will practice it anyway by getting around the “tick a box” prohibition. But no, there should not be jobs completely reserved for people who have a certain race of gender identity

Some environmental campaigners claim that attempts to create a circular economy for plastics are doomed to fail – but the arguments can be disingenuous

Using genomic data from more than 9500 species, biologists have mapped the evolutionary relationships between flowering plants

Two important barriers to a stable, powerful fusion reaction have been leapt by an experiment in a small tokamak reactor, but we don’t yet know if the technique will work in larger devices

The Large Hadron Collider is testing entanglement in a whole new energy range, probing the meaning of quantum theory – and the possibility that an even stranger reality lies beneath

Scientists use laser ablation technology to develop a deformable micro-supercapacitor.

Researchers have found that people following healthy eating accounts on social media for as little as two weeks ate more fruit and vegetables and less junk food.

A computer game helped upper secondary school students become better at distinguishing between reliable and misleading news.

Researchers have invented a new optical element that brings us one step closer to mixing the real and virtual worlds in an ordinary pair of eyeglasses using high-definition 3D holographic images.

Researchers have invented a new optical element that brings us one step closer to mixing the real and virtual worlds in an ordinary pair of eyeglasses using high-definition 3D holographic images.