Researchers working on a near-universal coronavirus vaccine that could stop outbreaks before they get started have reported success in mice. The vaccine confers immunity against the original SARS virus, despite it not being one of the viruses used to build it.There's little doubt that plenty of viruses currently circulating in animals will one day make the jump to humans. Moreover, viruses that have already made that leap will continue to mutate, creating new versions that will evade existing immunity. In a more connected world, such diseases have the potential to spread, and even kill, much faster.Swifter processes to produce new vaccines may help, but it's never great to be playing catch up. The solution lies in “proactive vaccinology”, finding ways to protect against viruses that don't yet exist or have not yet infected humans. Although we can never know with certainty the effectiveness of such a vaccine until the virus emerges, Dr Rory Hills of the University of Cambridge and colleagues hope to have something that would provide reasonable confidence.“Our focus is to create a vaccine that will protect us against the next coronavirus pandemic, and have it ready before the pandemic has even started,” Hills, first author of the new study, said in a statement.  “We’ve created a vaccine that provides protection against a broad range of different coronaviruses – including ones we don’t even know about yet.”Defending against a truly new type of virus, one with no cousins already infecting humans, could be an almost impossible task. Threats like that are rare, however. Almost all the diseases that plague humanity have close relatives, most notably in the case of coronaviruses. “We don’t have to wait for new coronaviruses to emerge. We know enough about coronaviruses, and different immune responses to them, that we can get going with building protective vaccines against unknown coronaviruses now,” said Cambridge's Professor Mark Howarth.Their experimental vaccine is called a “Quartet Nanocage”. At its core is a ball of tightly-bound nanoparticles to which viral antigen chains are attached with a type of "protein glue" they and their colleagues created.Exposure to these chains trains the immune system to target regions of coronaviruses that remain consistent across multiple varieties. The team of researchers is hardly alone in attempting to produce a proactive coronavirus vaccine. A few scientists have been working on the idea since the original SARS outbreak in 2003, and inevitably efforts accelerated with the COVID-19 pandemic and the vaccine-making advances that came with it.However, the researchers claim their approach is simpler to develop than alternatives. That may sound unlikely, since they are using an array of antigens rather than just one, but if they're right it could make for a more rapid progress, particularly now its promise has been demonstrated. The team used Receptor-Binding Domains (RBDs) from the “Spikes” of four coronaviruses, including the original Wuhan strain of COVID-19 for injection into mice. They compared this with alternative approaches that used some of the same technology but lacked key stages of the process. Although all the methods tested produced an array of antibodies, the Quartet Nanocage produced both the broadest and strongest response.Crucially, the resulting antibodies were able to neutralize the original SARS1 virus. Replacing the Wuhan strain in the vaccine with the “Kraken” version of Omicron demonstrated the capacity to neutralize the original. Similarly, a version where an RBD from the original SARS1 virus was used proved effective against currently circulating variants. The broadening of responses also worked for mice whose immune systems had previously been primed with the Wuhan spike, indicating the approach could be helpful for people who have already received other COVID vaccines, or been infected.As the authors note, medical technologies that work in mice do not always translate to humans. Moreover, even if some protection is provided, the extent of that protection is not known, and probably can't be until the relevant virus emerges. Nevertheless, a widespread vaccine that reduces infections even modestly might have been all we needed in the early days of the pandemic to prevent it from running out of control. Perhaps most importantly, the same basic technique may prove applicable to other families of viruses, such as influenza.The study is published in the journal Nature Nanotechnology.

Here's a question that surfaces on the Internet every now and then (and not from the usual suspects of conspiracy theorists and cranks): why are there so few photographs of Neil Armstrong on the Moon?There are people under the belief that there are no photos of Neil Armstrong on the Moon. This is not the case. There are photographs of the first man on the Moon, as well as plenty of footage.     However, it is true that there are very few photographs of him on there. In fact, the trash bags the crew left on the lunar surface feature in more photographs than Neil Armstrong.There are photos of Armstrong on the Moon, although one is of him reflected in Buzz Aldrin's visor, and one is of his backside. Neil Armstrong reflected in Buzz Aldrin's visor.Image credit: NASANot his best angle.Image credit: NASAThere are other stills of Armstrong on the Moon, though they were shot by movie cameras onboard the Lunar Module. In one, he is seen raising the US flag with Buzz Aldrin, while another gives a view of his face.Neil Armstrong's face seen from the Lunar Module camera.Image credit: NASA/Andrew ChaikinThe reason for the lack of photographs is fairly simple; Armstrong was the one holding the camera for the majority of their time on the Moon. There are plenty of photos of Buzz Aldrin on the Moon as a result, though both later said that they were not at all focused on who was included in the photographs, concentrating on the mission at hand. 

Scroll through social media during the summertime and it wouldn’t be unusual to come across plenty of people enjoying the sunshine and warmth. But in the last few years, there have also been those putting out warnings that antidepressants can make you more vulnerable to the effects of heat – so how true are these claims?What's the evidence?The center for regulating body temperature, or thermoregulation, is a tiny structure in the middle of the brain called the hypothalamus. It’s this region that some evidence suggests a class of antidepressant medication known as tricyclic antidepressants (TCAs) might affect in such a way that it makes it more difficult to regulate heat.When we can’t regulate our body’s response to warmer weather, it’s known as heat intolerance, which can cause people to feel overheated and sweat excessively."Also [typically] the body has a good way of telling us when we are thirsty, but these medications can diminish that – and they can also lower blood pressure slightly, which can lead to a chance of fainting in the heat," Dr Lawrence Wainwright, a researcher in the University of Oxford’s psychiatry department, told the BBC.However, TCAs aren’t prescribed as often nowadays; people are more often given a newer class of drugs known as selective serotonin or serotonin/norepinephrine reuptake inhibitors, SSRIs or SNRIs. Wainwright also said there’s some evidence to suggest that SSRIs impact thermoregulation too.But on the whole, the body of evidence that could explain why people on antidepressants are reporting struggling in the heat remains incompletely understood, at least until further research is carried out – though scientists have some ideas.“What we know is that different types of antidepressants [such as SSRIs and SNRIs] influence different chemical messengers called neurotransmitters,” Dr Chi-Chi Obuaya, consultant psychiatrist at Nightingale Hospital, told Stylist. “The main ones are noradrenaline/norepinephrine, dopamine and, predominantly, serotonin – and the heat intolerance some people experience is most likely caused by a complex interplay between these.”Sweaty side effectsThough the effect of antidepressants on the brain’s temperature regulation center is unclear, there’s a known side effect of several of these medications that could still put people at risk of heat-related illness: excessive sweating.Known as hyperhidrosis, it’s a common side effect for both SSRIs and TCAs, particularly at night. This sweating can then ramp up even more during a heatwave, which can put people at increased risk of dehydration and the effects that come with that, such as headaches, dizziness, and fatigue.How to stay coolIf you’re on antidepressants and feeling the heat, it’s not recommended to stop taking your medication; going cold turkey comes with its own set of uncomfortable side effects. Instead, it’s suggested to take the usual advice when it comes to staying cool:Drink plenty of fluidsAvoid going outside if possibleKeep cool inside by closing windows and keeping curtains/blinds closedAvoid exercisingAll “explainer” articles are confirmed by fact checkers to be correct at time of publishing. Text, images, and links may be edited, removed, or added to at a later date to keep information current.The content of this article is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of qualified health providers with questions you may have regarding medical conditions.

If you look at a current version of the periodic table, it appears complete. Since 2010, the entire seventh period has been filled, but the eighth period has not been started. It’s easy to wonder if we have discovered, or created, every element possible. Even if this is not the case, one might wonder whether some future maximum exists, beyond which it is impossible to create further elements. The answer is probably not – but there are some interesting complications to that.First, a little chemistry refresher. Elements are defined by the number of protons in their nucleus. Six protons and it’s carbon, 26 protons mean iron, 92 uranium. An element’s atomic number equals its proton count. All elements, other than hydrogen, need some neutrons to hold the protons together, but it’s the number of protons that matter. Indeed, in most cases, the nucleus will be either stable or fairly long-lasting with several different numbers of neutrons, creating different isotopes of the element. For example, there are five stable isotopes of nickel.The periodic table was initially constructed from naturally occurring elements based on similarities in their chemistry, and filled as far as uranium. Realizing elements with more than 92 protons were not found in nature, scientists started trying to make them.Synthetic elementsWe’ve now made 26 of these “transuranic” elements. None of them are stable. The reason we don’t find them in nature is not that they were never produced; almost certainly many of them have been made in supernovae and kilonovae. However, all are sufficiently radioactive that any whose origins predate the Earth have long since decayed to other elements. Production by more recent events has been far too limited to introduce detectable quantities to the Solar System.Producing the first transuranic elements proved relatively easy. Neptunium and plutonium were made by bombarding uranium with light nuclei so that some got captured to produce still heavier elements. Producing enough plutonium to make an atomic bomb may have been a major challenge during World War II, but as the process was refined it proved too easy for humanity’s good thereafter. With half-lives of hundreds of thousands or millions of years, neither element had survived from the Earth’s beginning, but once made there was plenty of time to study their properties.The next elements along the seventh period, americium and curium, were made only a few years later by a similar process and without much greater difficulty. Their half-lives are shorter, but still easily long enough to build up stocks of either element for research. From the late 1940s to the 1960s, new elements were announced every few years, steadily stepping further along the table – and even making it to song.   Some were produced deliberately by bombarding heavy elements with light nuclei, others found in the fallout from nuclear weapons tests.However, the further along period 7 one goes, the harder it has proven to make new elements, and the shorter their half-lives have turned out to be, although the pattern is not perfect. Roentgenium (atomic number 111) and Darmstadtium (110) both have their longest-lived isotopes measured in seconds, but Roentgenium lasts longer than Darmstadtium, despite being one step further along.Once you get to Moscovium (115) even the longest half-life is measured in milliseconds. We can’t really study its chemistry, because even if we could make a lot of it, very little would be left in the time it took to conduct an experiment. No new elements have been announced since 2010 when tennessine (117) was made, although names and official recognition of the most recent elements occurred in 2015/2016. Oganesson (118) produced earlier than tennessine, has an even shorter half-life at less than a millisecond, and only a handful of atoms have been made.So, is this it?Probably not. There is no theoretical reason why heavier elements should not be possible. The table’s periods reflect the elements’ chemistry, caused by electrons, rather than the physics of the nucleus, so there is nothing theoretically stopping us from starting another row. Nevertheless, given how hard it has proven to make the last few elements, we can expect it to be harder still to make more and observe them before decay. There’s no unbreakable limit like the speed of light, but the level of difficulty can be expected to keep increasing.Plot Twist – A Possible Island Of Stability More than 50 years ago physicists proposed that somewhere around atomic number 164 there could be an “island of stability”. More recently one of the main proponents has been Dr Yuri Oganessia, whose name might look rather familiar, reflecting the respect with which he is viewed by colleagues in the heavy element-making field.Producing elements with such a large nucleus would still be difficult, to say the least. Yet if we can get there, the idea runs, they would last for long periods of time.A prediction for the stablity of isotopes based on their numbers of protons and neutronsImage Credit: Yuri OrganessianRecently, the idea got a kick-along from the fact that asteroids such as 33 Polyhmnia and Psyche appear to be very dense, astonishingly so in Polyhmnia’s case. It’s likely this apparent density just reflects measuring errors – we may be overestimating the mass and underestimating their volume.A much more tantalizing explanation, however, is that these asteroids are built around cores of elements near the proposed island of instability. Elements’ density does not increase exactly in line with atomic number, but generally speaking, those with higher numbers are denser, and anything with an atomic number in the 160s should be staggeringly heavy.If forged by the phenomenal force of a kilonova, such elements would be eternal, or nearly so. Small amounts could have made their way to our Solar System. Within planets, they would sink to the center and represent such a small part of the core as to be undetectable, but a decent lump could raise the average density of an asteroid to the point we notice something odd.A more whimsical vision of the quest to find distant islands of stability.Image Credit: Yuri OrganessianIf this is true, and we could return a sample of such elements to Earth, it could form the basis for making elements with atomic numbers into the 170s. These might be beyond the island of stability, and therefore very short-lived, but could still be possible to produce very briefly.

Having a permanent human presence on the lunar surface requires being able to use resources found on the Moon – not everything can be brought from Earth. But it is unlikely that the base will be on the hot spot of everything it needs. Some stuff will have to be transported. Cars (well, buggies) on the Moon are nothing new, but researchers are considering something quite different: A levitating railway system.The project is called FLOAT, standing for Flexible Levitation On A Track. The goal is to provide payload transportation that is autonomous, reliable, and efficient. It aims to move payloads to and from spacecraft landing zones to the base, and transport lunar soil (regolith) from the mining location to the place where resources are extracted or where the soil is used for construction.What’s exciting about the technology is that the tracks are not fixed. They are unrolled directly onto the lunar regolith, so FLOAT needs minimal site preparation. Levitating robots will move over the tracks, and not having wheels or legs is advantageous as they do not have to deal with the sharp regolith and its damaging power.The flexible film track is made of a graphite layer that allows for diamagnetic levitation, while a flex circuit generates electromagnetic thrust. The third layer is actually optional, but it is a solar panel so that when in sunlight, the system doesn’t even require external energy. While the robots might have different sizes, the team estimates that 100 tons of material can be moved by multiple kilometers every day.FLOAT is one of the six NASA Innovative Advanced Concepts (NIAC) that have moved to phase II. Others include a new propulsion system to send astronauts to Mars quickly and a liquid space telescope concept. For FLOAT, phase II will focus on designing and manufacturing a scaled-down version of the system to be tested on a Moon-analogous environment, as well as a better understanding of environmental impacts on tracks and robots, and what else is needed to turn this concept into a reality.“These diverse, science fiction-like concepts represent a fantastic class of Phase II studies,” said John Nelson, NIAC program executive at NASA Headquarters in Washington, in a statement. “Our NIAC fellows never cease to amaze and inspire, and this class definitely gives NASA a lot to think about in terms of what’s possible in the future.” These projects received $600,000 to continue investigating feasibility. The FLOAT leader is Ethan Schaler, from NASA’s Jet Propulsion Laboratory. If the system continues to show its capabilities, it might be a crucial infrastructure on the Moon as soon as the 2030s.Phase I projects have also been announced and the proposals go from new telescope designs, technologies to make Mars less toxic, and even a swarm of tiny spacecraft that could travel to our nearest stars in a couple of decades.  

If you’ve ever noticed yourself getting a headache just before a storm hits, it might not be a coincidence. In fact, weather conditions are commonly reported as a trigger for headaches and migraine attacks. Unfortunately, it’s not yet within our power to change the weather; but we can help ensure that you’re informed about why an oncoming storm may have you reaching for the painkillers as well as your raincoat.Many people with migraine or who are prone to headaches say that weather can be a trigger. The American Migraine Foundation states that just over a third of migraine sufferers feel that particular weather conditions can bring on an attack, and the UK’s National Health Service lists bad weather among 10 common headache triggers. While anecdotally many people will relate to this phenomenon, the scientific studies on the topic have been a bit more mixed in their results. But there is one particular meteorological factor that comes up time and time again: pressure. Atmospheric pressure and headachesChanges in atmospheric pressure have been repeatedly blamed for headaches and migraine attacks. This explains why some people get headaches on airplanes – air pressure is lower at higher altitudes, and although aircraft cabins are pressurized, you can still feel the effects of the pressure changes during take-off and landing. For some, this means that their ears “pop”, causing temporary hearing loss and, in more severe cases, pain and dizziness. For others, it can lead to a case of what’s been called “airplane headache”. It’s a relatively new name for an issue that’s most likely been around since humans started traveling in big metal tubes in the sky, and it’s usually a stabbing pain towards the front of the head that gets better once the pressure has equalized again.But drops in atmospheric pressure don’t only happen at high altitude. They can also precede a storm, and that’s one of the proposed explanations behind weather-induced headaches.A 2019 review took an in-depth look at barometric pressure headaches, and cited a number of studies showing an association between decreased pressure and headache or migraine symptoms. For example, one study of over 7,000 patients in 2009 concluded that “lower barometric pressure led to a transient increase in risk of headache requiring emergency department evaluation.”However, the review authors pointed out that overall, “the results of [studies into barometric pressure headaches] are inconsistent regarding their directionality and fail to establish a strong association.” A more recent review in 2023 made a similar conclusion. How could atmospheric pressure cause headaches?Despite the mixed results on the topic, it’s hard to ignore the fact that so many headache and migraine patients report worsening symptoms when the air pressure drops – so what could be causing their pain?There are a few different theories, but one of the most commonly cited is its effect on the trigeminal nerve. This is the largest cranial nerve, which branches into the scalp and face and is implicated in many headache and facial pain disorders.There is some literature to suggest that the trigeminal nerve is vulnerable to changes in atmospheric pressure where it meets the narrow tubing of the middle ear. A study in rats in 2010 helped plant the seeds of the link between the trigeminal nerve and weather-related headaches. Decreased air pressure was found to increase electrical activity in certain neurons in the brainstem nucleus that relays sensory information from the face. The authors concluded that similar mechanisms could be at play in humans, and could potentially be responsible for barometric pressure headaches. Building on this, a small pilot study in 2021 found that people exposed to changes in barometric pressure for periods of 8 minutes at a time often reported a feeling of pressure in the head and ears, with a few experiencing mild to moderate headaches. The authors called for a bigger study to see if this could be the reason behind some people’s weather-related headaches.Barometric pressure headaches may also originate from pressure imbalances in the sinuses, as neurologist Dr Elizabeth Hartman explained for the University of Nebraska-Lincoln Health Center, which can cause pain in the front of the head and behind the eyes. A sudden drop in atmospheric pressure can also worsen an existing headache or migraine in this way.Other weather-related headache triggersBarometric pressure may not be the whole story. According to the American Migraine Foundation, both temperature and humidity have been implicated as possible triggers for some people. The overall picture seems to be that these kinds of triggers vary greatly across headache sufferers. One study from 2000 demonstrated how migraine patients exposed to the same weather phenomenon – warm westerly wind patterns in southern Canada called chinooks – reported worsening symptoms at different times in response to different conditions.The fact that so many people report weather as a trigger for their headaches or migraines shows it should not be dismissed out of hand, and there is some research to back them up; however, there is still a need for larger, rigorous studies to clearly establish what might be going on.For now, if you are someone whose head aches at the first inkling of storm clouds on the horizon, you might be able to cheer yourself up a little bit by impressing your friends with your near-clairvoyant powers of weather forecasting. Just remember: a magician never reveals their secrets. All “explainer” articles are confirmed by fact checkers to be correct at time of publishing. Text, images, and links may be edited, removed, or added to at a later date to keep information current. The content of this article is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of qualified health providers with questions you may have regarding medical conditions. 

Like a cuckoo laying its eggs in the nest of an unsuspecting host, the ancient Greeks are said to have infiltrated the city of Troy by hiding inside an enormous wooden horse. From Homer to Hollywood, the tale of this military masterstroke has been told for thousands of years, yet there’s little evidence to suggest it actually happened.According to the legend, the Achaeans – led by Agamemnon and boasting heroic soldiers such as Achilles – spent 10 years besieging Troy without managing to break through the city’s defenses. Pretending to give up, the assailants sailed to a nearby island, leaving behind a massive wooden horse filled with soldiers.Believing that the giant statue was an offering to the god Athena, the Trojans hauled the horse through their city gates and into the defenseless heart of their town, unaware of the enemies hiding within its belly. As night fell, the Greek soldiers emerged from their horse and laid waste to Troy, bringing an end to the epic war.However, archaeologists are yet to discover any solid evidence for the Trojan War, let alone its somewhat ridiculous finale. What we do know is that Troy was probably the name of a Bronze Age city at what is now Hisarlk in western Turkey. Discovered by German explorer Heinrich Schliemann in the 1870s, the site has yielded a small number of arrowheads and evidence of fire within a layer of sediment dated to around 1200 BCE, which roughly lines up with the date mentioned by Homer in his epic poem Iliad and could therefore hint at an ancient battle. Linking these finds to a decade-long siege, however, is a bit of a stretch.As for the big old horse, Homer really only mentions it in passing in Odyssey, and the first substantial description of the event can be found in the Aeneid, composed by the Roman poet Virgil more than a millennium after the ploy was supposedly executed. Most modern archaeologists take the ancient artist’s words with a pinch of salt and suspect that the giant horse was probably metaphorical rather than literal.For example, Dr Armand D'Angour from Oxford University has explained that “archaeological evidence shows that Troy was indeed burned down; but the wooden horse is an imaginative fable, perhaps inspired by the way ancient siege-engines were clothed with damp horse-hides to stop them being set alight.”In other words, the mythical Trojan Horse may have been more akin to a battering ram or other war machines that enabled the Achaeans access to Troy via much less subtle means than the story suggests. Unfortunately, however, it’s highly unlikely that archaeologists will ever find the remains of such a contraption – horse-like or otherwise – since wooden artifacts from antiquity tend to decompose long before they could possibly be discovered.Despite this, the idea of the Trojan Horse has become ingrained in modern culture and parlance, even lending its name to a type of computer malware that invades victims’ systems by disguising itself as an innocuous piece of code. Bizarre as the original idea may seem, the concept is the perfect metaphor for something that invades and destroys from within.Perhaps that’s why the ancient poets invented the Trojan Horse to represent the way in which Agamemnon and company took down the city of Troy.

The Earth is currently moving around the Sun at around 107,000 kilometers per hour (66,500 miles per hour), while the Sun hurtles through the galaxy at 828,000 kilometers per hour (514,500 miles per hour).We know this through centuries of observing the planets and the stars, and observing their motion relative to our planet. You see evidence of the Earth's spin constantly, as the Sun and stars move across the sky as we rotate like a gigantic kebab. If you're willing to put the effort in, you could also observe nearby stars apparently changing position in the sky (known as parallax) throughout the year, gathering your own evidence of Earth's orbit around the Sun. You could also observe stellar aberration, building a case for the model of the Solar System we figured out centuries ago.          But, of course, there are people out there on the planet who don't believe this is true. In a recent post by one confused individual, they post the Earth's movement through the Solar System and galaxy, and the fact that we can still do things like tightrope walks and stacking rocks, as "proof" that the model is incorrect.           IFLScience is not responsible for content shared from external sites.This is, of course, a hot mess of a post that demonstrates a profound misunderstanding of physics. The idea appears to be that the fact that we don't feel the planet hurtling through the galaxy somehow proves that the planet is stationary.In fact, the reason why we don't feel the Earth move at breakneck (and everything else) speeds is because there is no such thing as an absolute frame of reference in the universe. When not accelerating or decelerating, you are at rest, whether you are hurtling along on Earth, on a rocket heading away from Earth, or slowly orbiting the solar system on Planet 9 (if it exists).A body at rest remains at rest, while a body in motion remains in motion until another force acts upon it, known as inertia. This is the state you are in as you travel on the Earth. The Earth's motion is relatively smooth, though it is slowed and sped up by various factors, including earthquakes. If it were more jerky, you would feel the acceleration and deceleration (from forces being applied to the Earth) but you do not feel constant velocity or inertia.Think about when you are in an airplane. When the vehicle begins to accelerate, you feel this force being applied to you via the chair behind and beneath you. But once the aircraft stops accelerating and achieves a constant speed, your frame of reference is at rest, and you feel as stationary as if you were on the Earth (which, remember, is actually hurtling through the universe). The rocks of the above post are not immune from the laws of motion and inertia. They continue on the path they are set on (in this case, being a cute little stack following the motion of the Earth) until a force (some jerk knocking them over) is applied to them. As well as not having to worry about the motion of the Earth throughout the galaxy (only his frame of reference), the tightrope walker in the post (Philippe Petit) also benefits from the Earth dragging most of our atmosphere along with it through frictional forces.While a stationary Earth would explain why the rocks do not fall over, it would not explain many of the other things (such as parallax of the stars) that we have observed, nor be able to make predictions about the movement of the bodies in the universe – which is why we abandoned that model centuries before the meme was made.

We all know what happens when a meteorite breaks apart as it passes through the heavens, right? Of course we do. The parts of the celestial object that fall to Earth accumulate as a translucent gelatinous substance that evaporates soon after it appears, leaving no trace of its existence.While this may sound like a description from a sci-fi story, it is actually based on a very real substance that has fascinated and baffled people for a long time. For centuries, people from across the UK, Europe, and later the US have discovered what has been called “astromyxin”, “star jelly”, “astral jelly”, “star rot” or something similar, in fields and marshes. But while it was always thought to be a product of the heavens, the source of this gooey mass has a very terrestrial origin, one that is a little gory.A splattering of history Accounts of star jelly are not rare; in fact, descriptions of the substance have appeared in various sources, from folklore and art to natural histories. Discoveries of the snot-like stuff have been reported by both lay people and learned individuals alike.In most cases, someone witnesses a shooting star and then stumbles across an unknown substance in a field. Such discoveries usually occur at dawn, and whatever has been found typically disappears soon after.You can understand why people might be puzzled by the sight of this stuff.Image credit: Matauw/Shutterstock.comIn the 13th century, John of Gaddesden, a medieval physician, described what he called stella terrae (“star of the Earth”) in one of his medical texts. According to his writing, it was “a certain mucilaginous substance lying upon the earth” that could be used to treat particular ailments, such as abscesses.Later, in 1619, Robert Fludd, a physician and mystic, described how he had witnessed a meteor falling from the sky. He searched for its remains and, so the story goes, came across a mass of white slippery stuff containing black dots the next morning. This, he believed, was his shooting star.Similarly, in 1656, the metaphysical poet Henry More reportedly explained that “the Starres eat those falling Starres, as some call them, which are found on the earth in the form of a trembling gelly, are their excrement".Even in the 20th century, people reported coming across the substance. In several accounts, the jelly appeared to fall from the sky onto unfortunate residents, as was said to have happened in Reading, Massachusetts in 1983. Similarly, in 1995, a jelly-like substance was allegedly found in a garden in Oxfordshire, England, and was so abundant that it could “fill a kettle”.It is even possible that the phenomenon was known to non-European/Western people too. During the 1950s, Francis Huxley, the British botanist, reported that the Urubu people of Brazil believed that stars sometimes fell from the sky. He claimed to have come across one himself while exploring the jungle – it was a soft blue jelly-like substance.What the sludge? Obviously, star slime has nothing to do with actual meteorites or stars. We know that most meteors are made of rock and ore and, if any of them pass into our atmosphere, they quickly become super-heated. There is no way a gelatinous substance could ever survive such conditions.Still, for as long as star jelly has been identified, people have attempted to explain what it is. The more naturalistic explanations – ones that do not involve falling stars – started to appear in the 17th century, during the heyday of the Scientific Revolution. Various individuals associated with the Royal Society dealt with the substance, including Robert Boyle and Christopher Merrett. The latter explained how various people thought “star-shoot” could be a fungus, some sort of ram ejaculate, or even the leftovers of “dissolved frogs”, as bones had been found among the jelly bits.  Merrett eventually decided that the jelly was indeed related to frogs and apparently demonstrated that it came from a poor amphibian that had been chewed up by cows. John Morton later reached similar conclusions in his The Natural History of Northamptonshire. He even claimed to identify blood vessels and pieces of skin within the goo.Space goo, this is not.Image credit: emka74/Shutterstock.comOver the years, other explanations have been offered, which include the stuff being a byproduct of cyanobacteria, the fruiting bodies of slime molds, or something vomited up by birds and mammals. However, the most likely answer comes back to the frogs.It is probable that star jelly does indeed comes from eviscerated amphibians that have been ripped apart and devoured by predators. As this happens, their ovum jelly is released, which then expands as it comes into contact with moisture – such as the morning dew or rain. Anyone casually examining the gloop may not see any evidence of its former owner, nor any eggs, as they would likely be eaten quickly.So, far from being something mystical from the heavens, the mystery of star jelly probably relates to some very unfortunate amphibians. Still, the story of the substance has shown just how curious people are about unusual discoveries like this, as well as the efforts they will go to to explain them.  

Among its other hellish conditions, Venus is bone dry, despite having once had plenty of water. Where did it all go? A new analysis attributes it to “dissociative recombination”, which caused a loss of hydrogen atoms at twice the rate of previous estimates.Science fiction writers once set their works in the oceans of Venus, which they imagined sat beneath those endless clouds. Once spacecraft checked our neighbor out, the horrifying heat made clear there’d be no liquid water – but where was all the water vapor? Scientists have continued to ponder why Venus is hot and dry, rather than hot and wet, and what the implications might be for planets with more hospitable temperatures.Venus probably started out with a fairly similar amount of water to Earth. Yet it has a hundred-thousandth as much left, all of it in the atmosphere, rather than being distributed between ice, ocean, and air like Earth’s.Once Venus had similar amounts of water to Earth. It must have gone somewhere.Image Credit: NASAThe turbocharged Greenhouse Effect on Venus would have boiled off its water, leading to the steam escaping. However, if steam loss was the whole story, water equivalent to a global layer 10-100 meters (33-330 feet) deep should have been left behind.“As an analogy, say I dumped out the water in my water bottle. There would still be a few droplets left,” said Dr Michael Chaffin of the University of Colorado, Boulder in a statement. Chaffin is part of a team blaming the molecule HCO+, which they have already identified as a major culprit in Mars losing most of its water.There’s evidence to support the confidence Venus once had Earth-like quantities of water. Deuterium (hydrogen’s isotope with one neutron) is less likely to escape than ordinary hydrogen, and the ratio of hydrogen to deuterium reveals how much was once present.Whether there is a little H2O in Venus’s atmosphere or a lot, some of it combines with carbon dioxide at altitudes to produce HCO+. However, the upper atmosphere also has plenty of free electrons, which recombine with the HCO+, leaving carbon monoxide and hydrogen atoms.As the lightest element, hydrogen escapes easily from small planets’ gravity when it doesn’t have a heavier partner to anchor it. Unlike helium, hydrogen bonds easily to other atoms, so in the normal course of events it stays home. HCO+ provides a stepping stone to hydrogen becoming free long enough to escape. In Venus’s case, Chaffin and co-authors think, so much escaped that there’s not enough left to make water, and the oxygen has to go bond with something else.In order to explain Venus’s desiccated state, the team thinks there must have been a lot more HCO+ in its atmosphere than previously anticipated.Once all the hydrogen is lost, the HCO+ will be gone, but the authors don’t think we’re there yet. They think it should still be possible to identify small amounts of the molecule to confirm their hypothesis. “One of the surprising conclusions of this work is that HCO+ should actually be among the most abundant ions in the Venus atmosphere,” Chaffin said.Once HCO+ was included in the models, Chaffin and co-authors found the anticipated amount of water roughly matches what we see today, and the hydrogen/deuterium ratio is in the right ballpark as well.None of the spacecraft we have sent to Venus have detected any HCO+. However, the team thought that is because the instruments they carried were not suited to finding it.The forthcoming Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging (DAVINCI) won’t change that, but if this explanation is judged plausible future missions might. Much more than our understanding of Venus rests on this.“There haven’t been many missions to Venus,” study co-author Dr Eryn Cangi said. “But newly planned missions will leverage decades of collective experience and a flourishing interest in Venus to explore the extremes of planetary atmospheres, evolution and habitability.”“Water is really important for life,” Cangi added. “We need to understand the conditions that support liquid water in the universe, and that may have produced the very dry state of Venus today.”The study is published in the journal Nature.