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Astronauts face multiple risks during space flight, such as microgravity and radiation exposure. Microgravity can decrease bone density, and radiation exposure is a carcinogen. However, those are chronic effects.

The biggest risk to astronauts is fire since escape would be difficult on a long mission to Mars or elsewhere beyond Low Earth Orbit. Scientists are researching how fire behaves on spacecraft so astronauts can be protected.

Scientists from the Center of Applied Space Technology and Microgravity (ZARM) at the University of Bremen are investigating the risks of fire onboard spacecraft. They’ve published a new study in the Proceedings of the Combustion Institute titled “Effect of oxygen concentration, pressure, and opposed flow velocity on the flame spread along thin PMMA sheets.” The lead author is Hans-Christoph Ries.

“A fire on board a spacecraft is one of the most dangerous scenarios in space missions,” said Dr. Florian Meyer, head of the Combustion Technology research group at ZARM. “There are hardly any options for getting to a safe place or escaping from a spacecraft. It is therefore crucial to understand the behavior of fires under these special conditions.”

Since 2016, ZARM has been researching how fire behaves and spreads in microgravity conditions like those in the ISS. Those conditions also include an oxygen level similar to Earth’s, forced air circulation, and ambient pressure similar to Earth’s. NASA has been conducting similar experiments, and now we know that fire behaves differently in microgravity than it does on Earth.

Initially, a fire will burn with a smaller flame and take longer to spread. This is to the fire’s advantage since it won’t be noticed as quickly. Fire also burns hotter in microgravity, meaning that some materials that may not be combustible in normal Earth conditions could burn in spacecraft, creating toxic chemicals in the spacecraft’s air.

Spacecraft for Mars missions will have different environments than the ISS. The ambient air pressure will be lower, which provides two benefits: it makes the spacecraft lighter and also allows astronauts to prepare for external missions more quickly. However, the lower ambient pressure introduces another critical change in the spaceship environment. The oxygen content has to be higher to meet the astronauts’ respiration needs.

In these latest tests, the team at ZARM tested fire in these revised conditions.

PMMA stands for polymethyl methacrylate and is usually called acrylic. It’s a common material used in place of glass because it’s light and shatterproof. The ISS doesn’t use it, but it’s being developed for use in future spacecraft. The Orion capsule uses acrylic fused to other materials for windows, and future spacecraft will likely use something similar.

In their experiments, the researchers lit acrylic glass foils on fire and varied three environmental factors: ambient pressure, oxygen content and flow velocity.

This table from the figure is the test matrix for the experiments. The X’s and the single O indicate flow rates: X = 100 mm/s, O = 30–200 mm/s. Image Credit: Ries et al. 2024.

They used the Bremen Drop Tower to simulate microgravity.

The experiments showed that lower ambient pressure dampens fire. However, higher oxygen content has a more powerful effect. The ISS’s oxygen level is 21%, just as it is on Earth. Future spacecraft with lower ambient pressures will have oxygen levels as high as 35%. That translates into a huge increase in the risk astronauts face from fire. The results show that a fire can spread three times faster than it would under Earth conditions.

“Our results highlight critical factors that need to be considered when developing fire safety protocols for astronautic space missions.”

Dr. Florian Meyer, Combustion Technology research group at ZARM This figure from the study shows a time series of infrared images of the tests. They show fire on an acrylic film under microgravity conditions with 100 mm/second airflow, 75 kPa, and 28.3% oxygen. The white dashed lines show the contour of the acrylic sample. The green dotted lines are the evaluation lines used to measure the fire’s propagation rate. In panel b, the pink horizontal bar below the propagation front is the igniter. Image Credit: Ries et al. 2024.

We all know increased airflow spreads fire faster; that’s why we blow on a small flame to create a larger fire. Increased airflow delivers more oxygen, increasing combustion, so increased airflow in a higher-oxygen atmosphere creates a dangerous situation for astronauts.

“Our results highlight critical factors that need to be considered when developing fire safety protocols for astronautic space missions,” said Dr. Florian Meyer. “By understanding how flames spread under different atmospheric conditions, we can mitigate the risk of fire and improve the safety of the crew.”

The post The Most Dangerous Part of a Space Mission is Fire appeared first on Universe Today.

The way oil drops break up at the water's surface means some oil may not get cleaned up after a spill.

As the number of major utility-scale ground solar panel installations grows, concerns about their impacts on natural hydrologic processes also have grown. However, a new study by Penn State researchers suggests that excess runoff or increased erosion can be easily mitigated -- if these 'solar farms' are properly built.

Retinol, which is commonly added to anti-ageing skincare products, may improve hydration by interacting with bacteria on the skin

When a massive star dies in a supernova explosion, it’s not great news for any planets or stars that happen to be nearby. Generally, the catastrophic event crisps nearby worlds and sends companion stars careening through space. So, astronomers were pretty surprised to find 21 neutron stars—the crushed stellar cores left over after supernova explosions—orbiting in binary systems with Sun-like stars.

A team led by Caltech’s Kareem El-Badry detected these cosmic oddities using observations made by the European Space Agency’s Gaia mission. Its astrometrical data revealed “wobbles” in the orbits of the Sun-like companions. The team then followed up with spectral observations of the objects. Essentially, this work helped uncover a new population of what the team terms “dark” neutron stars still in orbital dances with their sunlike partners. Now the trick is to explain why these unusual pairs exist, according to El-Badry.

“We still do not have a complete model for how these binaries form,” he said. “In principle, the progenitor to the neutron star should have become huge and interacted with the solar-type star during its late-stage evolution.”

Astronomers have discovered 21 stars like our Sun in orbit around neutron stars (formed in supernova explosions). The European Space Agency’s Gaia mission detected this wobble by observing the orbits of the Sun-like stars (yellow dots) for three years. The Sun-like stars are green in this animation, and the neutron stars (and their orbits) are purple. Credit: Caltech/Kareem El-Badry Surviving a Supernova?

It seems counterintuitive to think of the nearby star surviving the nearby catastrophe. The process itself begins as the massive progenitor star ages and expands. That pushes the smaller star around. Just before the supernova occurred, the dying star probably engulfed the companion for a time. Some theories suggest that the engulfment itself could destroy the smaller star. Others say that it affects the star but doesn’t completely obliterate it.

At some point, the larger star’s core collapses when it runs out of fuel. All the other layers come crashing down on the core. The temperatures and pressures in the event compress what’s left of the core into a ball of neutrons. Then, the outer layers rebound off the core and blast out into space. That’s the part we see as the supernova explosion. The outburst should eject it from the system if there’s still a companion star. However, for these strange binaries, that didn’t happen. The neutron star and a companion remain.

Now it’s El-Badry’s team task to figure out why. “The discovery of these new systems shows that at least some binaries survive these cataclysmic processes even though models cannot yet fully explain how,” he said. In a paper about the finding, the team also suggests that they cannot rule out that the neutron stars may be ultramassive white dwarfs or white dwarf binaries.

The Search for Neutron Stars and their Companions

The Gaia mission aims to scan the sky and look for “wobbles” in the motions of more than a billion stars. The orbits of planets around the stars cause wobbles. However, the gravitational tug of nearby black holes, neutron stars, or more massive stars also induces them.

Neutron stars are massive balls of neutrons about 20 km across but denser than the Sun. They’re created as the collapsing stellar layers crush the core of the supernova progenitor star. As the neutron star and its companion orbit around a common center of mass, the neutron star tugs on its companion and that makes it shift back and forth—creating the telltale “wobble”. Gaia detected those wobbles, and then scientists used data from follow-up observations at several ground-based telescopes, including the W. M. Keck Observatory on Maunakea, Hawai‘i; La Silla Observatory in Chile; and the Whipple Observatory in Arizona. That gave them more information about the masses and orbits of the hidden neutron stars.

Now, there have been neutron stars in orbit with other Sun-like stars, those orbits have been pretty tight and close-in. In those cases, the mass transfer between the two companions makes the neutron star brighter in X-ray or radio wavelengths. That’s not true for the 21 systems El-Badry’s team studied. They are much farther apart in wider orbits. This limits how much material the neutron star can steal from its companion. As a result, those objects are dark and quiet. “These are the first neutron stars discovered purely due to their gravitational effects,” El-Badry said.

An animation of a binary star system containing a neutron star created in a supernova and a Sun-like companion. Credit: Caltech/R. Hurt (IPAC) Tracing the Tale from Supernova to Binary

So, now astronomers have a population of neutron star/Sun-like star binaries to explain. Now, the team will work to figure out the real story of why these rare pairings still exist. “We estimate that about one in a million solar-type stars is orbiting a neutron star in a wide orbit,” El-Badry said.

He’s also interested in similar matchups between dormant (and largely invisible) black holes and Sun-like stars. There are two that he knows about, including one called Gaia BH1, which is only 1,600 light-years away from us. The fact that these odd couples also exist opens up a lot of questions. “We don’t know for sure how these black hole binaries formed either,” El-Badry said. “There are clearly gaps in our models for the evolution of binary stars. Finding more of these dark companions and comparing their population statistics to predictions of different models will help us piece together how they form.”

For More Information

Sun-Like Stars Found Orbiting Hidden Companions
A Population of Neutron Star Candidates in Wide Orbits from Gaia Astrometry

The post Stars Can Survive Their Partner Detonating as a Supernova appeared first on Universe Today.

A jiggling robot has revealed the ideal vibrating speed to free jumbled fibres

A new camera could prevent companies from collecting embarrassing and identifiable photos and videos from devices like smart home cameras and robotic vacuums. It's called PrivacyLens.

A new camera could prevent companies from collecting embarrassing and identifiable photos and videos from devices like smart home cameras and robotic vacuums. It's called PrivacyLens.

Europe's next big space mission -- a telescope that will hunt for Earth-like rocky planets outside of our solar system -- is on course to launch at the end of 2026. PLATO, or PLAnetary Transits and Oscillations of stars, is being built to find nearby potentially habitable worlds around Sun-like stars that we can examine in detail.

A new study suggests that the U.S. government's push to increase heavy-duty trucks' energy efficiency could encourage more shipping by truck instead of rail, reducing the policies' anticipated effectiveness by 20%.

So far, only about ten intermediate-mass black holes have been discovered in the entire universe. The newly identified black hole causes surrounding stars in a cluster to move in an unexpectedly orderly way.

The flowless zinc-bromine battery (FLZBB) is a promising alternative to flammable lithium-ion batteries due to its use of non-flammable electrolytes. However, it suffers from self-discharge due to the crossover of active materials, generated at the positive graphite felt (GF) electrode, to the negative electrode, significantly affecting performance. Now, researchers have developed a novel nitrogen-doped mesoporous carbon-coated GF electrode that effectively suppresses self-discharge. This breakthrough can lead to practical applications of FLZBB in energy storage systems.

Researchers have developed a new formal description of internal world models, thereby enabling interdisciplinary research. Internal world models help to make predictions about new situations based on previous experience and to help find one's bearings. The new formalized view helps to compare world models of humans, animals and AI and to eliminate deficits.

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The VIPER moon rover was due to launch in 2025 but NASA has suddenly cancelled it, citing budgetary issues, despite the spacecraft being fully built

The UK had no plans for preventing or limiting the spread of a covid-19-like infection because it assumed the next pandemic would be caused by an unstoppable flu virus, an inquiry into the outbreak has revealed

This morning something got screwed up with the wildlife post, and so it was posted by accident when it was only partially written.  That means that the email went out with about 15% of the post included. If you read posts on the emails, then, I urge you to go back to Bruce Lyon’s original post, which has three videos and many photos of adorable Arctic fox cubs, at the new site.

I have no idea what happened, but it was a pain to restore the post. It is, however, well worth perusing, as those cubs are somethin

NOTE:  I put this post up the other day, but then got a very irate email from a Kiwi saying that no, I was WRONG: Health New Zealand, he asserted, never sent around any notice to employees encouraging them to say spiritual prayers (karakia) during the day: a Māori custom.  I objected to this as a mixing of religion and government (governmental health efforts), as well as a partial sacralization of indigenous practices. Because of the correspondent’s objection, and because I had no original evidence for such a notice being sent out—just a reader’s assertion—I pulled the post. I also informed a NZ outlet, which had asked to republish my post, to hold off until they could get evidence that such a notice about karakia was indeed circulated.

The organization in NZ has now procured such evidence, so I’m reposting what I took down, but have added the notice (with a link) verifying the government’s urging employees to pray.  And to the person who told me in very strong terms that no such notice existed, well, this is a family site and I won’t tell him what to do—but you can guess.

My post, now with the notice and a link to it:

This item, from the Breaking Views website in New Zealand, is one of the rare cases of a Kiwi speaking up against forcible adherence to Māori customs on the job—in this case, saying Māori prayers. First, “Health New Zealand,” the organization in question, is a government agency that, according to its own description:

. . . . will manage all health services, including hospital and specialist services, and primary and community care. Hospital and specialist services will be planned nationally and delivered more consistently across the country. Primary and community services will be commissioned through four regional divisions, each of which will network with a range of district offices (Population Health and Wellbeing Networks) who will develop and implement locality plans to improve the health and wellbeing of communities.

And the author of this short plaint, A. E. Thompson, is described as “a working, tax-paying New Zealander who speaks up about threats to our hard-fought rights, liberties, egalitarian values, rational thinking and fair treatment by the state.”  He or she is also courageous! (It’s not clear whether Thompson is employed by Health New Zealand; if so, that won’t be for long!)

The beef is that the government sent out a notice to Health New Zealand’s staff encouraging them to say Māori prayers daily.  From the site:

I was made aware that Health New Zealand recently sent an email to its staff as follows:

“We encourage everyone to incorporate karakia daily. To help support you with this we have created some pre-recorded videos to learn karakia. Our resource is designed to give you some options that will enable you to learn and develop your confidence and skills. Note over time we will be adding more recordings for you to choose from.”

The word ‘karakia’ surely must be a Maorified way of saying ‘prayer’, but it seems very difficult and may be impossible to determine whether the term was used before Europeans arrived or if there were other terms that iwi used for their incantations, chants and verbal offerings of respect to their various spiritual entities. Regardless, karakia almost always involve references to supernatural forces whether they be Christian (in practice, they usually end with ‘amine’), pagan or spiritualist. They often involve communication intended for (usually unspecified) long-dead ancestors.

Massey University assistant lecturer Te Rā Moriarty was quoted as saying: “Karakia allow us to continue an ancestral practice of acknowledging orally the divine forces that we, as Māori, understand as the sources of our natural environment. We call these forces atua. So, it is a way to connect through the words of our tūpuna to the world that we live.”

Here’s the notice that the NZ news site that was going to publish my post eventually found. And yes, it is real, and came with a note:

NAME REDACTED tells me she has been advised that an email was sent to employees and invited them to view the message in their browser.

Click the notice to see the announcement—on a Health New Zealand website. The “you can read more” link doesn’t work for me; it apparently requires credentials to access. But the notice says exactly what my informant claimed.  Yes, the New Zealand government is urging some of its employees to pray daily.

In the Māori dictionary, “karakia” is defined this way:

(noun) incantation, ritual chant, chant, intoned incantation, charm, spell – a set form of words to state or make effective a ritual activity. Karakia are recited rapidly using traditional language, symbols and structures. Traditionally correct delivery of the karakia was essential: mispronunciation, hesitation or omissions courted disaster. . . . .

So what we have is a government agency “encouraging” its staff to chant to supernatural powers in hope of connecting to one’s ancestors (tūpuna). This encouragement, of course, violates the separation of church and state, and is an unwarranted sop to the indigenous people. (New Zealand, of course, doesn’t have a First Amendment.)  It’s one more sign of how the sacralization of the oppressed is spreading in New Zealand.  Of course these prayers have no effect, and encouraging the descendants of “colonists” to say them is to force one’s beliefs on others who may not share them.

Thompson has a few words about this:

We can choose not to attend places where the religious practices feel offensive or intolerant to us, and the hosts in those places can exercise similar choice about visiting our spaces.

However, when we are employed and rely upon that employment for our survival, we don’t have the choice to avoid our place of employment. Being employed in a state service under a secular government, workers should have choice over whether they participate even passively in practices involving claimed spiritual entities or supernatural beliefs. Expecting employees to participate denies their right to choose to follow their own religion or philosophical belief and not other people’s, a characteristic of totalitarian rule.

This is especially true in New Zealand, where refusal to sacralize the presumed “oppressed” is sometimes punished severely, with threats of losing one’s job. Thompson’s piece continues:

Sure, the email to health staff only used the word “encourage” but really, when your employer issues an email saying that, you know it will be expected and that ignoring or opposing it will be held against you and may cost you your job.

Pressuring state employees and even private company employees to participate in karakia sets a dangerous precedent in eroding separation between state and religion. As we speak, Muslim immigrants in Europe are deliberately imposing their religious practices on non-Muslim populations by having their distorting loudspeakers call dozens or hundreds of faithful to prostrate themselves in prayer on public footpaths and roadways (even though nearby mosques are plentiful). The practice reflects their belief that Islam is so important that everyone either needs to convert to it or be discriminated against or killed.

As usual, I was sent this with the assumption that the sender would remain anonymous. Thompson, however, clearly has some guts, for even if he/she doesn’t work for Health New Zealand, it’s a huge risk to publish something like this anywhere.

After a long break doing field work, Bruce Lyon of UC Santa Cruz, now in Alaska working on birds, sent some photos of bonus mammals: cute Arctic foxed with added VIDEOS. His captions and IDs are indented, and you can enlarge his photos by clicking on them. His intro:

Since foxes are honorary cats on WEIT, I thought people would enjoy some photos and videos of an arctic fox (Vulpes lagopus) family on St Paul Island, Alaska, where I have spent the summer studying birds. There is a fox den in the boulders next to the beach near my lodging and the pair has a whopping nine pups! The other day all nine adorable fuzzballs were playing out in the open on the beach and I was able to watch and photograph their antics. There were lots of playfights, chases and pounces, tossing bits of dried fish into the air, chewing and attacking a piece of driftwood on the beach, and leaping up and pirouetting in the air.

Arctic foxes are native to St Paul Island and virtually all individuals are blue morph rather than white morph foxes. Occasionally, white morph individuals do get here by crossing the winter sea ice. The morphs are apparently produced by a single Mendelian gene (the MC1R gene). However, three of the pups have white feet, so perhaps the coat color is mostly but not entirely determined by the MC1R gene.

JAC: Here’s the location of St. Paul Island in the Priblofs (from Wikipedia):

A video best shows how adorable these fuzzballs are. Seven of the nine pups are in view:

Another video—the pups having fun with their driftwood toy:

One last video—a sibling’s tail makes for a great toy:

The fox playground. The pup on the right is in pounce mode and pounced on its sib just after I took the photograph:

A pup inspects a fish head. Someone from the local fish processing plant may have dumped a bunch of fish on the beach for the foxes but it is also possible that the parents dragged the fish here from wherever the fish scraps are dumped:

A chase:

These guys took a break from playfighting but then the one on the right batted its sib and in the process lost its balance and toppled over (the following photo):

Next few photos: Mom’s home!  The adult female showed up and the pups mobbed her. They were so excited to see her—lots of bouncing and tail-wagging. She nursed them for a bit (I think they had to take turns; too many to fit at one time) but she soon decided she had had enough and nipped at the kids to chase them off:

A pup checks me out:

Despite the hype, there is no evidence to show magnesium oil is effective for any purpose.

The post Magnesium oil: Not so magical first appeared on Science-Based Medicine.