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Humanity’s been fortunate to have a star situated over Earth’s north pole. The star, known as Polaris, or the North Star, has guided many sailors safely to port. But Polaris is a fascinating star in its own right, not just because of its serendipitous position.

Polaris is also called the Pole Star, and it’s actually a triple star system. The primary star is a yellow supergiant named Polaris Aa, about 448 light-years away, and it orbits with a smaller companion named Polaris Ab. The outer star is named Polaris B and may also have a dim companion. In this article, Polaris refers to the primary star, Polaris Aa.

These Hubble images show the locations of the Polaris stars. Polaris Aa is labelled Polaris A in this image, and Polaris AB is labelled Polaris B. Image Credit: By NASA/HST – (Image: STScI-2006-02), Public Domain.

Polaris hasn’t always been the North Star, and it won’t always be. Thuban was the North Star from the 4th to 2nd millennium BC until Earth’s axial precession gave that position to Polaris. The Pole Star changes during a 26,000-year cycle, so Thuban will take over from Polaris in the year 20346.

But whether Polaris is the Pole Star at a particular time or not, it’s an interesting object whose properties can help us understand the expansion of the Universe.

Polaris is a variable star that pulses and changes brightness over time. Specifically, it’s a Cepheid variable. Cepheid variables expand and contract rhythmically, and their brightness changes in a predictable pattern. Because there’s a direct relationship between their pulsation period and their luminosity, they’re useful in measuring distances. They’re called “standard candles” and are part of the cosmic distance ladder.

Astronomers use standard candles to help measure the Hubble constant, or how rapidly the Universe is expanding. But there’s some tension between our measurements of the Hubble constant. When we use local objects like Cepheid variables to measure the Hubble constant, we get a different number than when we use larger-scale things like the Cosmic Microwave Background to measure it.

Since Polaris is such a nearby standard candle, a team of astronomers used a telescope array to watch the star for 30 years. By more accurately observing Polaris and its smaller companion Polaris Ab, they hoped to constrain Polaris’ mass and other characteristics more accurately. This, in turn, could help us understand the tension in the Hubble constant. Along the way, the researchers uncovered some surprises surrounding this long-observed star.

Their results are in a paper titled “The Orbit and Dynamical Mass of Polaris: Observations with the CHARA Array.” It’s published in The Astrophysical Journal, and the lead author is Nancy Evans. Evans is an astrophysicist at the Center for Astrophysics | Harvard & Smithsonian.

In order to understand Polaris better, it’s critical to get a good look at its dim companion. But that’s not easy to do.

“The small separation and large contrast in brightness between the two stars makes it extremely challenging to resolve the binary system during their closest approach,” Evans said.

The CHARA (Center for High Angular Resolution Astronomy) Array was built to bring clarity to objects like Polaris and its dim companion. It’s an interferometer, an array of six separate telescopes, each with a one-meter-diameter primary mirror. By combining the images from each separate scope, CHARA attains the higher resolution of a telescope with a primary mirror that’s 330 meters in diameter, the area covered by the individual ‘scopes. CHARA has a special camera designed to work with it called MIRC-X (Michigan InfraRed Combiner-eXeter).

With these tools, the astronomers tracked Polaris and its dim companion over a 30-year period. They measured how the Cepheid variable changed size as it pulsated. They learned that it’s five times as massive as the Sun and has a diameter 46 times larger than the Sun. However, the mass measurement is affected by the star’s large orbital eccentricity, 0.63, so there’s still some uncertainty about Polaris’ mass.

The measured mass and luminosity also show that Polaris is more luminous than it should be for a star on its evolutionary track. “Polaris is at least 0.4 mag brighter than the predicted tracks,” the authors write in their paper. This is important because of the “Cepheid mass problem.” It’s a discrepancy between masses inferred from stellar evolutionary tracks and masses from pulsation calculations.

A Cepheid variable’s mass can be determined when it’s in a binary relationship. “Mass determination starts with a radial velocity (RV) orbit and pulsation curve for a binary containing a Cepheid,” the authors explain. Very few Cepheid variables are in binary relationships like Polaris, so it’s an important target for constraining and understanding their masses. These measurements are all important because they relate back to the cosmic distance ladder, standard candles, and the Hubble constant.

“The accuracy of inputs from any of these measurements depends on many characteristics of the star: brightness, orbital period, inclination, and the separation, distance, and mass ratio of the components. This means that each Cepheid system is unique and has to be analyzed independently,” the authors explain.

The observations also showed variable spots on the star’s surface.

“The CHARA images revealed large bright and dark spots on the surface of Polaris that changed over time,” said Gail Schaefer, director of the CHARA Array.

This CHARA Array false-colour image of Polaris from April 2021 reveals large bright and dark spots on the surface. Image Credit: Evans et al. 2024.

“The identification of starspots is consistent with several properties of Polaris,” the researchers write. It’s different from other Cepheid variables because it has a very low pulsation amplitude. That could mean that its atmosphere is more like a nonvariable supergiant. Those atmospheres often seem to be active, much like the spots on Polaris. “It is not clear how full amplitude pulsation affects the atmosphere and magnetic field in pulsators, so Polaris is an interesting test case,” they explain.

The spots are variable, which could explain why astronomers have struggled to identify other “additional periodicities” in the star. They could also explain an observed ~120-day radial velocity variation as a rotation period.

The spots on Polaris’ surface have added to the star’s complexity, and they’re begging to be understood.

“We plan to continue imaging Polaris in the future,” said study co-author John Monnier, an astronomy professor at the University of Michigan. “We hope to better understand the mechanism that generates the spots on the surface of Polaris.”

The post Polaris, Earth’s North Star, Has A Surprisingly Spotted Surface appeared first on Universe Today.

Researchers trained a polymer gel to play the computer game Pong by passing electric current through it and measuring the concentration of ions

After a star explodes, the resulting supernova remnant collapses in on itself and could begin the cycle again, creating generations of stars enriched with heavy elements

We have gained so much powerful knowledge in the past few hundred years. But there’s still so much that we don’t know.

There are limits to our current knowledge of the universe. In astronomy, we have recently discovered that 95% of the matter and energy contents of the universe, dubbed dark matter and dark energy, are of a form completely unknown to modern science. That means that everything we have ever studied and learned in our exploration of atoms, chemicals, and forces, every star we see in the night sky and every galaxy we observe in the distant cosmos, makes up less than 5% of the entire universe.

We have pushed our understanding of the history of the universe into the earliest moments of the big bang, with a firm grasp of the physics underlaying the first few minutes of the existence of the cosmos. But beyond that is murky haze, a tangled mess of unsolved mathematics and over-complicated physics. We do not understand the origins of our universe, or even if that question makes sense – if our knowledge of time and space even apply at such extreme scales.

Related to the questions of the beginning of the cosmos are the mysteries that abound in high-energy physics. We do not know how to merge our knowledge of gravity, as expressed through general relativity, with our understanding of quantum physics, which governs the other forces of nature. We do not know how gravity operates at extremely small scales, preventing us from understanding the big bang itself and the true nature of black holes.

Despite cracking the code of DNA and the role that genetics plays in the evolutionary process, we do not understand how life first arose on the Earth, and whether we are truly alone in the cosmos. We do not know how sexual reproduction arose, or where viruses originated from, or the full extent of life on Earth. We do not understand the full variety of molecular interactions that power our own biochemistry, or how the components of our cells came to find themselves working together.

We do not know if superconductors, which allow for the transmission of electricity with no resistance, is possible at room temperature. We do not know the full tectonic history of the Earth, or even if duplicates of the Earth’s climate system exist on other worlds orbiting alien stars.

We do not even understand the origins – or even nature – of our own conscious thoughts, the source of our thirst for knowledge and our capacity to access it.

We do not even know how we are able to ask these questions.

The post The Knowledge We Don’t Yet Have appeared first on Universe Today.

I’m off to the Blyde River Canyon today and most of tomorrow, so posts will be nonexistent or thin for a few days—save for Matthew’s postings of the Hili Dialogues.  I’ve largely avoided reading the news, as I find it depressing and not conducive to a relaxing vacation, but two readers sent me stuff about the Democratic National Convention that is taking place in Chicago.  I’m glad I’m not there.

Here’s one item that epitomizes the wokeness I fear is metastasizing in the body of the Democratic Party: a land acknowledgement to open the convention. I was sent a link to the video below, which YouTube describes as follows:

Two citizens of the Prairie Band Potawatomi Nation — Zach Pahmahmie, tribal council vice chair and Lorrie Melchior, tribal council secretary — gave the land acknowledgement Monday at the Democratic National Convention in Chicago, where Kamala Harris will step into the spotlight not as a running mate but at the top of the ticket.

And the video:

My response to these things is always the same: they are performative gestures signaling the virtue of the organization, but accomplish nothing. If the Democratic Party really does acknowledge that the lands on which the convention is taking place was stolen from Native Americans, why don’t they try to compensate the Potawatomi Nation for the theft? (Land in Chicago is expensive!)

Granted the speaker notes that the Interior Department placed some of their tribal lands into a trust, making the Potawatomie “the only federally recognized tribal nation in Illinois in 175 years.” But did any individual get land or cash?

And there are the expected pro-Palestinian protests. Here’s one where an American flag gets burned (legal speech), but a guy who tries to put it out gets jumped on and pushed away.

Breaking: The Pro-Palestinian mob has formed a circle and is cheering on burning an American flag.

A man tries to stop the flag from burning and is immediately physically assaulted and pushed out.

These are the true colors of this movement. pic.twitter.com/eMdJfSCP0G

— Eyal Yakoby (@EYakoby) August 21, 2024

This shows the divisiveness that plagues America, and that I fear will appear again on campus this fall.

I can’t find an article someone sent me relating that the Convention has given pro-Palestinian protestors far more space than pro-Israeli demonstrators, who have apparently been pushed far away from the site, but I do remember reading that somewhere. In the meantime, the Washington Post reports this:

. . . pro-Palestinian activists have won small but notable concessions at the Democratic National Convention that, three days into the event, have largely headed off any major eruptions of anger or division. Organizers have provided space for a panel to discuss Israeli-Palestinian conflict and for a vigil for Palestinians killed in Gaza [was there a vigil for the dead Israelis, including now six more hostages?], and several high-profile speakers have demanded an end to the war from the stage.

Those concessions have helped defuse the issue, but most critical has been the emergence of Vice President Kamala Harris as the Democratic nominee. Harris, in her public comments, has emphasized Palestinian suffering notably more than President Joe Biden has and held Israel more directly responsible for the high civilian death toll and the slow pace of humanitarian aid. In addition, her campaign has ramped up its efforts to engage with those calling for a change in U.S. policy.

This wokeness and anti-Israeli sentiment does of course worry me about Harris and the election, to the point where I’ve been contemplating not voting for President at all (there’s no question of me voting for Trump, who I think is unstable and dangerous). But make no mistake about it: if Harris wins, Israel is in for a hard time, with some Israelis even regarding Harris as an existential threat to their country. I’m hoping that they’re unjustly worried.

And I’m hoping the centrist Democrats will push back on the party’s new cooling toward Israel.  Above all, Democrats have to realize that a permanent cease-fire now is a victory for Hamas, and that the IDF has been more careful than any army in history in trying to reduce civilian casualities. Blame the deaths of Palestinian civilians not on Israel, as have Harris and Biden, but on Hamas, which actually wants the deaths of its own civilians as part of its strategy to win the world’s favor. And Hamas seems to be succeeding, even among Democrats.]

Finally, I wish that Harris would have some interviews or press conferences before the election; it’s surprising to me that’s she’s had exactly none. We all know why that is, of course, but Democrats resolved to support her will find some reasons why no such events are required.

If Democrats share “the contagious power of hope,” as Michelle Obama said in her speech, then my hope is that the Democratic party stops its movement towards its “progressive” wing.

Anyway, these are some early-morning thoughts before I take off to see the wonders of nature. Please discuss them but, as always, be civil to your fellow commenters and to your host. Debate is fine; insults are not.

It’s been less than two years (November 2022) since ChatGPT launched. In some ways the new large language model (LLM) type of artificial intelligence (AI) applications have been on the steep part of the improvement curve. And yet, they are still LLMs with the same limitations. In the last two years I have frequently used ChatGPT and other AI applications, and often give them tasks just to see how they are doing.

For a quick review, LLMs are AIs that are trained on vast amounts of information from the internet. They essentially predict the next work chunk in order to build natural-sounding responses to queries. Their responses therefore represent a sort-of zeitgeist of the internet, building on what is out there. Responses are therefore necessarily derivative, but can contain unique combinations of information. This has lead to a so-far endless debate about how truly creative LLMs can be, or if they are just stealing and regurgitating content from human creators.

What I am finding is that LLMs are getting better at doing what they do, but have not broken out of the limitations of this regurgitation model. Here is a good example from the New York Times – an author (Curtis Sittenfeld) wrote a short story based on the same prompt given to ChatGPT, and published both to see if readers could tell the difference. For me, I knew right away which story was AI. The author’s story was interesting and engaging. ChatGPTs story bored me before the end of the first paragraph. It was soulless and mechanical. It reminded me of a bad story written by a freshman in high school. It got the job done, and used some tired and predictable literary devices, but failed to engage the reader and lacked any sense of taking the reader on an emotional journey.

This reinforced for me what I suspected from my own interactions – LLMs are getting better at being LLMs, but have not broken out of their fundamental limitations.

Several people I know have observed that a good test for them will be if AI can tell a funny joke. This is the subject of this BBC article, which put that very idea to the test, with similar results. Here are some tests of my own, using ChatGPT 4. With the prompt: “Tell me a funny joke about scientists,” I got, “Why do biologists look forward to casual Fridays?  Because they’re allowed to wear genes to work!” We are at cringey dad-joke level. I pushed it for something more funny and creative and got: “Why did the physicist stop dating the biologist? Every time they got close, the biologist kept saying, “I need my space!”” That was even worse, plus it mixed up the punchline.

You get the same results with poetry or storytelling – tired, predictable, formulaic.

For now, I don’t think creative producers have much to worry about, at least not at the high end. Where these creative AIs are useful is at the low to medium end of quality, where predictable and “just get’s the job done” is adequate. AI can help generate ideas, or it can produce low-quality stuff for personal use. You will notice I sometimes use AI art for my blogs. The advantage is they are copyright free, and they can be exactly what I need. I don’t need high quality. For my purposes, getting the job done is perfect.

The “downside” is that the world will be flooded with mediocre art. I think we can survive this, however. It doesn’t really worry me. It may even push some people to get better than the mediocre level of AI, thereby raising the bar. I wonder if, going forward, AIs will push humans to be better in general, or if it will just make us lazy (probably both).

What ChatGPT and other LLMs are really good at is not being creative but doing predictable tedious tasks. For me personally, I use ChatGPT to augment my Google searches (beyond the results that are already built in). There are times when I am just not getting the results I want from Google. The results are overwhelmed with either recent news, commercial content, or pseudoscience. But a carefully worded prompt in ChatGPT can get me quickly to exactly the content I want and direct me to the references I need. There is still room for improvement here, but the results so far are great.

I also know people who use ChatGPT to draw up legal documents. These are supposed to be technical and boring, and copying boilerplate is actually what you want. I wouldn’t rely on this for anything serious, but if you need basic contracts for everyday work, it’s fine. I also know people who use LLMs to write computer code, and report that it can save them hours of work.

What these two examples also reflect is that LLMs can be used as expert helpers. A computer programmer can use LLM generated code that they can understand, test, and tweak. A lawyer can use an LLM to generate a legal document that they can also read and correct.

The bottom line of all this is that I do not think that LLMs are at the point where they replace either experts or creative content producers. However, they do have three very useful applications: They can be used to generate mediocre content for fun and personal use. They can be used to improve and automate tedious tasks. And they can be used as tools in the hands of experts to improve their efficiency and quality. They are also getting better that these three types of tasks.

But they have not gotten any closer, in my opinion, to replacing true human creativity.

The real interesting question is this – will LLMs get to the point where they do produce creative output at a human level, or will something fundamentally different be necessary? I am leaning toward the latter. The deeper question is – what is true creativity? Can an algorithm produce content that does not seem algorithmic? Will having more complex algorithms suffice, meaning that getting beyond a certain critical point of complexity produce the illusion of true creativity? Or are the creative processes happening in the human brain beyond the LLM approach?

So far I have not seen any evidence to convince me that LLMs are capable of true creativity. But they remain technically very useful. Perhaps it’s not fair to judge them by what they are worst at, and rather to simply use them for what they are best at.

The post AI Humor first appeared on NeuroLogica Blog.

Meanwhile, in Dobrzyn, Hili is on the look-out:

Hili: I see the enemy.
A: Where?
Hili: Sitting under the bush

Hili: Widzę wroga.
Ja: Gdzie?
Hili: Siedzi pod krzakiem.

On Sept. 26th, 2022, NASA’s Double Asteroids Redirect Test (DART) collided with Dimorphos, the small moonlet orbiting the larger asteroid Didymos. In so doing, the mission successfully demonstrated a proposed strategy for deflecting potentially hazardous asteroids (PHAs) – the kinetic impact method. By October 2026, the ESA’s Hera mission will rendezvous with the double-asteroid system and perform a detailed post-impact survey of Dimorphos to ensure that this method of planetary defense can be repeated in the future.

However, while the kinetic method could successfully deflect asteroids so they don’t threaten Earth, it could also create debris that might reach Earth and other celestial bodies. In a recent study, an international team of scientists explored how this impact test also presents an opportunity to observe how this debris could someday reach Earth and Mars as meteors. After conducting a series of dynamic simulations, they concluded that the asteroid ejecta could reach Mars and the Earth-Moon system within a decade.

The research team was led by Dr. Eloy Peña-Asensio, a Research Fellow with the Deep-space Astrodynamics Research and Technology (DART) group at the Polytechnic Institute of Milan. He was joined by colleagues from the Autonomous University of Barcelona, the Institute of Space Sciences (ICE-CSIS), part of the Spanish National Research Council, the Catalonia Institute of Space Studies (IEEC), and the European Space Agency (ESA). The paper that details their findings recently appeared online and has been accepted for publication by The Planetary Science Journal.

For their study, Peña-Asensio and his colleagues relied on data obtained by the Light Italian CubeSat for Imaging of Asteroids (LICIACube), which accompanied the DART mission and witnessed the kinetic impact test. This data allowed the team to constrain the initial conditions of the ejecta, including its trajectories and velocities – ranging from a few tens of meters per second to about 500 m/s (1800 km/h; ~1120 mph). The team then used the supercomputers at NASA’s Navigation and Ancillary Information Facility (NAIF) to simulate what will become of the ejecta.

These simulations tracked the 3 million particles created by the DART mission’s impact with Dimorphos. As Peña-Asensio told Universe Today via email:

“LICIACube provided crucial data on the shape and direction of the ejecta cone immediately following the collision. In our simulation, the particles ranged in size from 10 centimeters to 30 micrometers, with the lower range representing the smallest sizes capable of producing observable meteors on Earth with current technology. The upper range was limited by the fact that only ejected centimeter-sized fragments were observed.”

Their results indicated that some of these particles would reach Earth and Mars within a decade or more, depending on how fast they traveled after the impact. For example, particles ejected at velocities below 500 m/s could reach Mars in about 13 years, whereas those ejected at velocities exceeding 1.5 km/s (5,400 km/h; 3,355 mph) could reach Earth in as little as seven years. However, their simulations indicated that it will likely be up to 30 years before any of this ejecta is observed on Earth.

This illustration shows the ESA’s Hera spacecraft and its two CubeSats at the binary asteroid Didymos. Credit: ESA

“However, these faster particles are expected to be too small to produce visible meteors, based on early observations,” said Peña-Asensio. “Nevertheless, ongoing meteor observation campaigns will be critical in determining whether DART has created a new (and human-created) meteor shower: the Dimorphids. Meteor observing campaigns in the coming decades will have the last word. If these ejected Dimorphos fragments reach Earth, they will not pose any risk. Their small size and high speed will cause them to disintegrate in the atmosphere, creating a beautiful luminous streak in the sky.”

Peña-Asensio and his colleagues also note that future Mars observation missions will have the opportunity to witness Martian meteors as fragments of Didymos burn up in its atmosphere. In the meantime, their study has provided the potential characteristics these and any future meteors burning up in our atmosphere will have. This includes direction, velocity, and the time of the year they will arrive, allowing any “Dimorphids” to be clearly identified. This is part of what makes the DART mission and its companion missions unique.

In addition to validating a key strategy for planetary defense, DART has also provided an opportunity to model how ejecta caused by impacts could someday reach Earth and other bodies in the Solar System. As Michael Küppers, the Project Scientist of the ESA’s Hera mission and co-author of the paper, told Universe Today via email:

“A unique aspect of the DART mission is that it is a controlled impact experiment, i.e., an impact where the impactor properties (size, shape, mass, velocity) are accurately known. Thanks to the Hera mission, we will also know the target properties well, including those of the DART impact site. Data about the ejecta came from LICIACube and earth-based observations after the impact. There is probably no other impact on a planetary scale with that much information about the impactor, the target, and the ejecta formation and early development. This allows us to test and improve our models and scaling laws of the impact process and ejecta evolution. Those data provide the input data (source location, size, and velocity distribution) used by the ejecta evolution models.”

Further Reading: arXiv

The post Debris from DART could Hit Earth and Mars Within a Decade appeared first on Universe Today.

While a NASA probe heads for an asteroid known as Psyche, telescopes have been probing it to prepare for the arrival. Data from the James Webb Space Telescope has found something quite unexpected on the surface – hydrated molecules and maybe even water! The origin of the water is cause for much speculation, maybe it came from under the surface or from chemical interactions with the solar wind! 

Asteroid Psyche was discovered in 1852 by the Italian astronomer Annibale de Gasparis. It was named after the Greek goddess of the soul who was born mortal and married Eros. It measures 225 km across and is one of the most massive objects in the asteroid belt between Mars and Jupiter. Most of the asteroids in the belt are composed of rock and ice but Psyche seems to be different being largely composed of metals, perhaps the exposed core of a protoplanet that lost its outer layers. Psyche is of immense interest to study because it provides an opportunity to study planetary cores which are usually inaccessible. 

Illustration of the metallic asteroid Psyche. Credit: Peter Rubin/NASA/JPL-Caltech/ASU

Aptly named Psyche, the probe launched by NASA has already started its 3.5 billion km journey to the asteroid, due to arrive in August 2029. With its solar panels deployed, the probe measures 25 metres by 7.3 metres, about the size of a tennis court. It has a mass of 2,747 kg and is powered by five solar panel arrays. Once arrived at Psyche they can generate about 3 kilowatts of power.

While the probe is enroute, telescopes on Earth and in space have been exploring Psyche. Observations in different wavelengths of light have provided information that will aid and support the data collected by the Psyche spacecraft. The study was led by Dr. Stephanie Jarmak from the Southwest Research Institute and it was their observations that confirmed the hydroxyl molecules on the surface. 

Image of NASA engineers preparing the Psyche spacecraft for launch within a clean room at the Astrotech Space Operations Facility located near the NASA Kennedy Space Center. Psyche is scheduled to launch in October 2023 on a SpaceX Falcon Heavy rocket from historic Launch Complex 39A at Kennedy. (Credit: NASA/Ben Smegelsky)

The data, which was collected using the James Webb Space Telescope revealed the telltale signs of hydroxyl but stopped short of explaining where they came from. There are two possible explanations and we can look to the origin of asteroids to understand them. They are the leftovers from the formation of planets and their make up is determined by the location in the solar nebula from which they formed. If the hydroxyl formed locally without interference from external process then it might suggest that Psyche is not a planetary core remnant.  It might be that Psyche simply formed at a distance that volatile compounds like water condense to form solids like ice before migrating. 

An alternative model explains the variability of the molecule distribution across the surface. This might indicate that impacts from carbonaceous chondrites (like the meteorites often found on Earth) could have provided the water molecules that have been observed. 

It seems that for now, we will have to wait until the arrival of the Psyche spacecraft in 2029 to unravel the mystery. If we can get a better understanding of the origin of the asteroid Psyche it will help us to learn more about the distribution of elements in the nebula that the planets formed from. In particular, understanding more about the distribution of water will help us to develop a better insight to the origins of life. 

Source : SwRI-Ked Team Finds Evidence of Hydration on Psyche

The post There Might Be Water on the Surface of the Metal Asteroid Psyche appeared first on Universe Today.

Around 25 per cent of the world’s population has intestinal parasite infections – these could hinder the effectiveness of covid-19 vaccines, according to research in mice

Who are we? Why are we here? We are stardust, the result of chemistry occurring throughout vast clouds of interstellar gas and dust. To better understand how that chemistry could create prebiotic molecules, researchers investigated the role of low-energy electrons created as cosmic radiation traverses through ice particles. Their findings may also inform medical and environmental applications on our home planet.

Who are we? Why are we here? We are stardust, the result of chemistry occurring throughout vast clouds of interstellar gas and dust. To better understand how that chemistry could create prebiotic molecules, researchers investigated the role of low-energy electrons created as cosmic radiation traverses through ice particles. Their findings may also inform medical and environmental applications on our home planet.

A team of researchers has developed the first transmission electron microscope which operates at the temporal resolution of a single attosecond, allowing for the first still-image of an electron in motion.

Researchers used machine learning to determine how much global warming has influenced extreme weather events in the U.S. and elsewhere in recent years. Their approach could change how scientists study and predict the impact of climate change on extreme weather.

Physicists have demonstrated a bizarre cooling effect by setting up a detector to record the absence of photons in a laser experiment

A reluctant Catherine de Lange tries tempering for the first time and discovers how to make gloriously glossy chocolate to decorate a cake with

Watching US politicians and former generals as they react to a simulated attempted coup after a disputed US election in the documentary War Game is fascinating – but it leaves many questions unanswered, finds Bethan Ackerley

The veteran presenter adds authority to Secret Lives of Orangutans, a film about a family of endangered orangutans in Sumatra. File this new entry in his vast oeuvre under lovable but lightweight

After 25 years in orbit, the Chandra X-ray Observatory is under threat. We need to protect this monument to human ingenuity, argues Chanda Prescod-Weinstein

A curious Feedback delves further into the invention of the Morbid Curiosity Scale and discovers how it might help with certain "short-term mating goals"