This image overlays over 100 fireball images recorded between 2016 and 2020. The streaks are fireballs; the dots are star positions at different times. Desert Fireball NetworkPatrick M. Shober, NASA Much of what scientists know about the early solar system comes from meteorites – ancient rocks that travel through space and survive a fiery plunge through Earth’s atmosphere. Among meteorites, one type – called carbonaceous chondrites – stands out as the most primitive and provides a unique glimpse into the solar system’s infancy. The carbonaceous chondrites are rich in water, carbon and organic compounds. They’re “hydrated,” which means they contain water bound within minerals in the rock. The components of the water are locked into crystal structures. Many researchers believe these ancient rocks played a crucial role in delivering water to early Earth. Before hitting the Earth, rocks traveling through space are generally referred to as asteroids, meteoroids or comets, depending on their size and composition. If a piece of one of these objects makes it all the way to Earth, it becomes a “meteorite.” From observing asteroids with telescopes, scientists know that most asteroids have water-rich, carbonaceous compositions. Models predict that most meteorites – over half – should also be carbonaceous. But less than 4% of all the meteorites found on Earth are carbonaceous. So why is there such a mismatch? In a study published in the journal Nature Astronomy on April 14, 2025, my planetary scientist colleagues and I tried to answer an age-old question: Where are all the carbonaceous chondrites?
Sample-return missions
Scientists’ desire to study these ancient rocks has driven recent sample-return space missions. NASA’s OSIRIS‑REx and JAXA’s Hayabusa2 missions have transformed what researchers know about primitive, carbon‑rich asteroids. Meteorites found sitting on the ground are exposed to rain, snow and plants, which can significantly change them and make analysis more difficult. So, the OSIRIS‑REx mission ventured to the asteroid Bennu to retrieve an unaltered sample. Retrieving this sample allowed scientists to examine the asteroid’s composition in detail. Similarly, Hayabusa2’s journey to the asteroid Ryugu provided pristine samples of another, similarly water-rich asteroid. Together these missions have let planetary scientists like me study pristine, fragile carbonaceous material from asteroids. These asteroids are a direct window into the building blocks of our solar system and the origins of life.Carbonaceous near-Earth asteroid Bennu as seen from NASA’s OSIRIS-REx sample-return spacecraft.NASA
The carbonaceous chondrite puzzle
For a long time, scientists assumed that the Earth’s atmosphere filtered out carbonaceous debris. When an object hits Earth’s atmosphere, it has to survive significant pressures and high temperatures. Carbonaceous chondrites tend to be weaker and more crumbly than other meteorites, so these objects just don’t stand as much of a chance. Meteorites usually start their journey when two asteroids collide. These collisions create a bunch of centimeter- to meter-size rock fragments. These cosmic crumbs streak through the solar system and can, eventually, fall to Earth. When they’re smaller than a meter, scientists call them meteoroids. Meteoroids are far too small for researchers to see with a telescope, unless they’re about to hit the Earth, and astronomers get lucky. But there is another way scientists can study this population, and, in turn, understand why meteorites have such different compositions.
Meteor and fireball observation networks
Our research team used the Earth’s atmosphere as our detector. Most of the meteoroids that reach Earth are tiny, sand-sized particles, but occasionally, bodies up to a couple of meters in diameter hit. Researchers estimate that about 5,000 metric tons of micrometeorites land on Earth annually. And, each year, between 4,000 and 10,000 large meteorites – golf ball-sized or larger – land on Earth. That’s more than 20 each day.A fireball observed by the FRIPON network in Normandy, France, in 2019. Today, digital cameras have rendered round-the-clock observations of the night sky both practical and affordable. Low-cost, high-sensitivity sensors and automated detection software allow researchers to monitor large sections of the night sky for bright flashes, which signal a meteoroid hitting the atmosphere. Research teams can sift through these real-time observations using automated analysis techniques – or a very dedicated Ph.D. student – to find invaluable information. Our team manages two global systems: FRIPON, a French-led network with stations in 15 countries; and the Global Fireball Observatory, a collaboration started by the team behind the Desert Fireball Network in Australia. Together with other open-access datasets, my colleagues and I used the trajectories of nearly 8,000 impacts observed by 19 observation networks spread across 39 countries.FRIPON camera installed at the Pic du Midi Observatory in the French Pyrenees.FRIPON By comparing all meteoroid impacts recorded in Earth’s atmosphere with those that successfully reach the surface as meteorites, we can pinpoint which asteroids produce fragments that are strong enough to survive the journey. Or, conversely, we can also pinpoint which asteroids produce weak material that do not show up as often on Earth as meteorites.Desert Fireball Network automated remote observatory in South Australia.The Desert Fireball Network
The Sun is baking the rocks too much
Surprisingly, we found that many asteroid pieces don’t even make it to Earth. Something starts removing the weak stuff while the fragment is still in space. The carbonaceous material, which isn’t very durable, likely gets broken down through heat stress when its orbit takes it close to the Sun. As carbonaceous chondrites orbit close, and then away from the Sun, the temperature swings form cracks in their material. This process effectively fragments and removes weak, hydrated boulders from the population of objects near the Earth. Anything left over after this thermal cracking then has to survive the atmosphere. Only 30%-50% of the remaining objects survive the atmospheric passage and become meteorites. The debris pieces whose orbits bring them closer to the Sun tend to be significantly more durable, making them far more likely to survive the difficult passage through Earth’s atmosphere. We call this a survival bias. For decades, scientists have presumed that Earth’s atmosphere alone explains the scarcity of carbonaceous meteorites, but our work indicates that much of the removal occurs beforehand in space. Going forward, new scientific advances can help confirm these findings and better identify meteoroid compositions. Scientists need to get better at using telescopes to detect objects right before they hit the Earth. More detailed modeling of how these objects break up in the atmosphere can also help researchers study them. Lastly, future studies can come up with better methods to identify what these fireballs are made of using the colors of the meteors. Patrick M. Shober, Postdoctoral Fellow in Planetary Sciences, NASA This article is republished from The Conversation under a Creative Commons license. Read the original article.
How extraterrestrial tales of aliens gain traction
The narrative explores humanity’s intrigue with extraterrestrial entities, juxtaposing evolutionary processes with claims of alien interventions, ultimately emphasizing the need for scientific evidence over fantastical stories. Aliens!
One night, upon returning to the cave that his tribe calls home, the monkey-humanoid Moon-Watcher finds a strange crystal object, a kind of monolith that fascinates him at first, but then quickly loses his interest when he discovers that it is not edible. Soon after, the true purpose of the monolith is revealed to be none other than penetrating the minds of our ancestors to induce new abilities that, over time, will cause the development of an intelligence capable of creating new technology.
Many readers will recognise this scene from the novel 2001, A Space Odyssey, by Arthur C. Clarke, and the film of the same name, directed by Stanley Kubrick. It almost goes without saying that the crystal monolith in question is the work of an extraterrestrial civilisation that observes life on other planets and “experiments” on them to encourage the development of intelligence in as many parts of the cosmos as possible.
Seeking simple answers to complex questions
Understanding how we, as a species, came to be intelligent is one of the great enigmas of evolutionary study. Small mutations, followed by a process of natural selection to choose the most advantageous, seems too slow a process for structures as complex as the human nervous system or brain to emerge. It is this very complexity that allows millions of neurons to communicate with each other, resulting in the emergence of qualities such as the ability to respond voluntarily to environmental stimuli, or to ask questions about the very nature of humankind and the universe.
This has always been the case, in all human cultures. A classic example would be attributing atmospheric events – thunder, lightning, floods – to the wrath of God. These ideas came about before humans had ever left the ground, so it is no surprise that we turned our eyes even higher – to extraterrestrials – to explain other phenomena that we could only observe once travelling at high altitudes became part of our daily lives.
The allure of the unknown
The possibility that we might have been visited by beings from other worlds has always fascinated us. The element of mystery, of the unknown, only makes it more interesting.
Any phenomenon is made all the more enticing when it seems it is being covered up or hidden for secretive reasons. The attractiveness of conspiracies often leads people towards ideas which have no scientific basis, such as the belief that the Earth is flat, that humans never set foot on the Moon, or that vaccines can control our behaviour.
Even though these ideas have repeatedly been shown to be untrue, their rapid dissemination through social media, using simple, blunt language that appeals to emotion over logic, makes them very powerful weapons.
The supposed “proof” of alien visits to our planet ranges from specific Bible passages to ancient stone carvings portraying creatures or objects that may appear to be aliens or spacecraft. The latter often take the form of flying saucers.
However, we cannot forget that humans have always created imaginary creatures that resemble them and attributed them with magical powers. When imagining Gods, humans have given them a human appearance, and almost always imagined them as living in the sky.
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When we look at these representations through modern eyes, we associate them with extraterrestrial beings or structures, when in fact they could be referring to a range of different things.
What we can be certain of is that the more we explore our skies, the more likely it is that we will encounter phenomena that we cannot explain. However, this does not mean that they are extraterrestrial. Past experience has shown us that most of these events can be attributed to optical illusions, spy or weather balloons, space junk, or even satellites that we ourselves have made.
In Spain, UFOs were a hot topic between the 1960s and the 1980s. In this era, everyone knew someone who was convinced that they had seen a UFO. This even reached the point where an exoplanet, called Ummo, was made up. It was populated by a more advanced civilisation than ours who made contact with people on Earth. In the letters these aliens supposedly sent, the ‘Ummites’ explained concepts such as genetics and cell structure.
The Ummo hoax was even linked to the creation of a paedophile ring, which should make us reflect on the harmful consequences that the spread of fabricated news stories can have.
Can we deny the possibility that intelligent alien civilisations exist?
The answer, of course, is no. The universe is immense, and it is more than likely that circumstances similar to those which led to the appearance of life on Earth have been repeated on other planets. But there is a huge distance (literally and figuratively) between acknowledging the existence of these creatures and considering the possibility that they might have visited us.
Exoplanets, also known as extrasolar planets, are extremely far away, and we are limited by the speed of light which, as proven by Einstein, is the maximum possible speed at which anything can travel. Therefore, the journey to even a “nearby” exoplanet would take thousands of years. Maybe a civilisation more advanced than ours could find a way to do it faster, but not to the point of it being something easy or commonplace.
In any case, if the remains of alien life or spacecraft are stored away somewhere, why are they not being shown to us? Scientists would jump at the chance to analyse this organic matter to find out how it is structured, how it metabolises energy, or what molecules it uses to store genetic information.
Until there is proof, this is not a question of science, but rather, of stories. Stories can be very entertaining, but these kinds of stories do not help us to build a more accurate or helpful view of the world.
The science section of our news blog STM Daily News provides readers with captivating and up-to-date information on the latest scientific discoveries, breakthroughs, and innovations across various fields. We offer engaging and accessible content, ensuring that readers with different levels of scientific knowledge can stay informed. Whether it’s exploring advancements in medicine, astronomy, technology, or environmental sciences, our science section strives to shed light on the intriguing world of scientific exploration and its profound impact on our daily lives. From thought-provoking articles to informative interviews with experts in the field, STM Daily News Science offers a harmonious blend of factual reporting, analysis, and exploration, making it a go-to source for science enthusiasts and curious minds alike. https://stmdailynews.com/category/science/
We’re only halfway through 2023, and it feels already like the year of alien contact.
In February, President Joe Biden gave orders to shoot down three unidentified aerial phenomena – NASA’s title for UFOs. Then, the alleged leaked footage from a Navy pilot of a UFO, and then news of a whistleblower’s report on a possible U.S. government cover-up about UFO research. Most recently, an independent analysis published in June suggests that UFOs might have been collected by a clandestine agency of the U.S. government.
If any actual evidence of extraterrestrial life emerges, whether from whistleblower testimony or an admission of a cover-up, humans would face a historic paradigm shift.
As members of an Indigenous studies working group who were asked to lend our disciplinary expertise to a workshop affiliated with the Berkeley SETI Research Center, we have studied centuries of culture contacts and their outcomes from around the globe. Our collaborative preparations for the workshop drew from transdisciplinary research in Australia, New Zealand, Africa and across the Americas.
In its final form, our group statement illustrated the need for diverse perspectives on the ethics of listening for alien life and a broadening of what defines “intelligence” and “life.” Based on our findings, we consider first contact less as an event and more as a long process that has already begun.
Who’s in charge of first contact
The question of who is “in charge” of preparing for contact with alien life immediately comes to mind. The communities – and their interpretive lenses – most likely to engage in any contact scenario would be military, corporate and scientific.
By giving Americans the legal right to profit from space tourism and planetary resource extraction, the Commercial Space Launch Competitiveness Act of 2015 could mean that corporations will be the first to find signs of extraterrestrial societies. Otherwise, while detecting unidentified aerial phenomena is usually a military matter, and NASA takes the lead on sending messages from Earth, most activities around extraterrestrial communications and evidence fall to a program called SETI, or the search for extraterrestrial intelligence.
SETI investigators are virtually always STEM – science, technology, engineering and math – scholars. Few in the social science and humanities fields have been afforded opportunities to contribute to concepts of and preparations for contact.
In a promising act of disciplinary inclusion, the Berkeley SETI Research Center in 2018 invited working groups – including our Indigenous studies working group – from outside STEM fields to craft perspective papers for SETI scientists to consider.
Ethics of listening
Neither Breakthough Listen nor SETI’s site features a current statement of ethics beyond a commitment to transparency. Our working group was not the first to raise this issue. And while the SETI Institute and certain research centers have included ethics in their event programming, it seems relevant to ask who NASA and SETI answer to, and what ethical guidelines they’re following for a potential first contact scenario.
SETI’s Post-Detection Hub – another rare exception to SETI’s STEM-centrism – seems the most likely to develop a range of contact scenarios. The possible circumstances imagined include finding ET artifacts, detecting signals from thousands of light years away, dealing with linguistic incompatibility, finding microbial organisms in space or on other planets, and biological contamination of either their or our species. Whether the U.S. government or heads of military would heed these scenarios is another matter.
SETI-affiliated scholars tend to reassure critics that the intentions of those listening for technosignatures are benevolent, since “what harm could come from simply listening?” The chair emeritus of SETI Research, Jill Tarter, defended listening because any ET civilization would perceive our listening techniques as immature or elementary.
But our working group drew upon the history of colonial contacts to show the dangers of thinking that whole civilizations are comparatively advanced or intelligent. For example, when Christopher Columbus and other European explorers came to the Americas, those relationships were shaped by the preconceived notion that the “Indians” were less advanced due to their lack of writing. This led to decades of Indigenous servitude in the Americas.This 16th century engraving shows Christopher Columbus landing in the Americas, where he and his explorers deemed the Indigenous people there as ‘primitive,’ as they had no writing system. Theodor de Bry/Wikimedia Commons
The working group statement also suggested that the act of listening is itself already within a “phase of contact.” Like colonialism itself, contact might best be thought of as a series of events that starts with planning, rather than a singular event. Seen this way, isn’t listening potentially without permission just another form of surveillance? To listen intently but indiscriminately seemed to our working group like a type of eavesdropping.
It seems contradictory that we begin our relations with aliens by listening in without their permission while actively working to stop other countries from listening to certain U.S. communications. If humans are initially perceived as disrespectful or careless, ET contact could more likely lead to their colonization of us.
Histories of contact
Throughout histories of Western colonization, even in those few cases when contactees were intended to be protected, contact has led to brutal violence, pandemics, enslavement and genocide.
James Cook’s 1768 voyage on the HMS Endeavor was initiated by the Royal Society. This prestigious British academic society charged him with calculating the solar distance between the Earth and the Sun by measuring the visible movement of Venus across the Sun from Tahiti. The society strictly forbade him from any colonial engagements.
Though he achieved his scientific goals, Cook also received orders from the Crown to map and claim as much territory as possible on the return voyage. Cook’s actions put into motion wide-scale colonization and Indigenous dispossession across Oceania, including the violent conquests of Australia and New Zealand.
The Royal Society gave Cook a “prime directive” of doing no harm and to only conduct research that would broadly benefit humanity. However, explorers are rarely independent from their funders, and their explorations reflect the political contexts of their time.
As scholars attuned to both research ethics and histories of colonialism, we wrote about Cook in our working group statement to showcase why SETI might want to explicitly disentangle their intentions from those of corporations, the military and the government.
Although separated by vast time and space, both Cook’s voyage and SETI share key qualities, including their appeal to celestial science in the service of all humanity. They also share a mismatch between their ethical protocols and the likely long-term impacts of their success. https://www.youtube.com/embed/5gZwLGrJQrM?wmode=transparent&start=0 This BBC video describes the modern ramifications of Captain James Cook’s colonial legacy in New Zealand.
The initial domino of a public ET message, or recovered bodies or ships, could initiate cascading events, including military actions, corporate resource mining and perhaps even geopolitical reorganizing. The history of imperialism and colonialism on Earth illustrates that not everyone benefits from colonization. No one can know for sure how engagement with extraterrestrials would go, though it’s better to consider cautionary tales from Earth’s own history sooner rather than later.
This article has been updated to correct the date of James Cook’s voyage.
The science section of our news blog STM Daily News provides readers with captivating and up-to-date information on the latest scientific discoveries, breakthroughs, and innovations across various fields. We offer engaging and accessible content, ensuring that readers with different levels of scientific knowledge can stay informed. Whether it’s exploring advancements in medicine, astronomy, technology, or environmental sciences, our science section strives to shed light on the intriguing world of scientific exploration and its profound impact on our daily lives. From thought-provoking articles to informative interviews with experts in the field, STM Daily News Science offers a harmonious blend of factual reporting, analysis, and exploration, making it a go-to source for science enthusiasts and curious minds alike. https://stmdailynews.com/category/science/
Flooding from hurricanes Helene and Milton inflicted billions of dollars in damage across the Southeast in September and October 2024, pushing buildings off their foundations and undercutting roads and bridges. It also caused dozens of electric vehicles and other battery-powered objects, such as scooters and golf carts, to catch fire.
According to one tally, 11 electric cars and 48 lithium-ion batteries caught fire after exposure to salty floodwater from Helene. In some cases, these fires spread to homes.
When a lithium-ion battery pack bursts into flames, it releases toxic fumes, burns violently and is extremely hard to put out. Frequently, firefighters’ only option is to let it burn out by itself.
Particularly when these batteries are soaked in saltwater, they can become “ticking time bombs,” in the words of Florida State Fire Marshall Jimmy Patronis. That’s because the fire doesn’t always occur immediately when the battery is flooded. According to the National Highway Traffic Safety Administration, about 36 EVs flooded by Hurricane Ian in Florida in 2022 caught fire, including several that were being towed after the storm on flatbed trailers.
Many consumers are unaware of this risk, and lithium-ion batteries are widely used in EVs and hybrid cars, e-bikes and scooters, electric lawnmowers and cordless power tools.
I’m a mechanical engineer and am working to help solve battery safety issues for our increasingly electrified society. Here’s what all owners should know about water and the risk of battery fires: https://www.youtube.com/embed/gWkEGEbpqFc?wmode=transparent&start=10 Emergency responders handle EVs that were immersed in saltwater during Hurricane Ian in Florida in 2022, including some that ignited.
The threat of saltwater
The trigger for lithium-ion battery fires is a process called thermal runaway – a cascading sequence of heat-releasing reactions inside the battery cell.
Under normal operating conditions, the probability of a lithium-ion cell going into thermal runaway is less than 1 in 10 million. But it increases sharply if the cell is subjected to electrical, thermal or mechanical stress, such as short-circuiting, overheating or puncture.
Saltwater is a particular problem for batteries because salt dissolved in water is conductive, which means that electric current readily flows through it. Pure water is not very conductive, but the electrical conductivity of seawater can be more than a thousand times higher than that of fresh water.
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All EV battery pack enclosures use gaskets to seal off their internal space from the elements outside. Typically, they have waterproof ratings of IP66 or IP67. While these ratings are high, they do not guarantee that a battery will be watertight when it is immersed for a long period of time – say, over 30 minutes.
Battery packs also have various ports to equalize pressure inside the battery and move electrical power in and out. These can be potential pathways for water to leak into the pack enclosure. Inadequate seal ratings and manufacturing defects can also enable water to find its way into the battery pack if it is immersed.
How water leads to fire
All batteries have two terminals: One is marked positive (+), and the other is marked negative (-). When the terminals are connected to a device that uses electricity to do work, such as a light bulb, chemical reactions occur inside the battery that cause electrons to flow from the negative to the positive terminal. This creates an electric current and releases the energy stored in the battery.
Electrons flow between a battery’s terminals because the chemical reactions inside the battery create different electrical potentials between the two terminals. This difference is also known as voltage. When saltwater comes into contact with metal battery terminals with different electrical potentials, the battery can short-circuit, inducing rapid corrosion and electric arcing, and generating excessive current and heat. The more conductive the liquid is that penetrates the battery pack, the higher the shorting current and rate of corrosion.
Rapid corrosion reactions within the battery pack produce hydrogen and oxygen, corroding away materials from metallic terminals on the positive side of the battery and depositing them onto the negative side. Even after the water drains away, these deposited materials can form solid shorting bridges that remain inside the battery pack, causing a delayed thermal runaway. A fire can start days after the battery is flooded.Most electric vehicles and plug-in hybrid cars use arrays of lithium-ion batteries like these. DOE
Even a battery pack that is fully discharged isn’t necessarily safe during flooding. A lithium-ion cell, even at 0% state of charge, still has about a three-volt potential difference between its positive and negative terminals, so some current can flow between them. For a battery string with many cells in a series – a typical configuration in electric cars – residual voltage can still be high enough to drive these reactions.
Many scientists, including me and my colleagues, are working to understand the exact sequence of events that can occur in a battery pack after it is exposed to saltwater and lead to thermal runaway. We also are looking for ways to help reduce fire risks from flooded battery packs.
These could include finding better ways to seal the battery packs; using alternative, more corrosion-resistant materials for the battery terminals; and applying waterproof coatings to exposed terminals inside the battery pack.
What EV owners should know
Electric cars are still very safe to drive and own in most circumstances. However, during extreme situations like hurricanes and flooding, it is very important to keep EV battery packs from becoming submerged in water, particularly saltwater. The same is true for other products that contain lithium-ion batteries.
For EVs, this means evacuating cars out of the affected zone or parking them on high ground before flooding occurs. Smaller objects, like e-bikes and power tools, can be moved to upper floors of buildings or stored on high shelves.
If you own an EV that has been submerged in water for hours to days, particularly in saltwater, public safety experts recommend treating it as a fire hazard and placing it on open ground away from other valuable property. Do not attempt to charge or operate it. Contact the manufacturer for an inspection to assess battery damage.
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Often, a flooded electric vehicle will need to be towed away for further inspection. However, since thermal runaway can occur well after submersion, the car should not be moved until it has been professionally assessed.
The science section of our news blog STM Daily News provides readers with captivating and up-to-date information on the latest scientific discoveries, breakthroughs, and innovations across various fields. We offer engaging and accessible content, ensuring that readers with different levels of scientific knowledge can stay informed. Whether it’s exploring advancements in medicine, astronomy, technology, or environmental sciences, our science section strives to shed light on the intriguing world of scientific exploration and its profound impact on our daily lives. From thought-provoking articles to informative interviews with experts in the field, STM Daily News Science offers a harmonious blend of factual reporting, analysis, and exploration, making it a go-to source for science enthusiasts and curious minds alike. https://stmdailynews.com/category/science/
