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Foi em 8 de março de 2014 que um Boeing 777-200ER decolou de Kuala Lumpur, na Malásia, rumo a Pequim, sob operação da Malaysia da Airlines. Cerca de 38 minutos após a decolagem, a aeronave fez contato com o controle de tráfego aéreo enquanto sobrevoava o mar do sul da China. Na sequência, o avião saiu da rota planejada e desapareceu dos radares.
O voo MH370 desapareceu dos radares civis 38 minutos após a decolagem, logo após a última mensagem do capitão Zaharie Ahmad Shah: "Boa noite, Malaysian três sete zero" — quando o comandante entrou em contato, o avião sobrevoava o espaço aéreo do Vietnã.
Com 239 pessoas de diversas nacionalidadess a bordo, a aeronave desviou drasticamente de sua rota original. Segundo dados de radares militares, o avião saiu da rota na direção do nordeste da Malásia, e depois seguiu na direção da ilha de Sumatra, na Indonésia. Na sequência, fez uma manobra para a direção sul e o contato foi perdido.
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Já fazem mais de 12 anos do desaparecimento do voo MH370 da Malaysia Airlines. Mesmo após tanto tempo, este mistério da aviação comercial moderna ainda segue em aberto — tanto que foi iniciada uma nova busca pelos destroços da aeronave em dezembro de 2025.
Até o momento, mais de 30 fragmentos isolados foram encontrados no litoral da África e de algumas ilhas no oceano Índico, confirmados como parte da aeronave; mesmo assim, o "corpo" do avião e as caixas-pretas permanecem ocultos.
Para os investigadores, encontrar o local do impacto é a única forma de encerrar as especulações. Um relatório de quase 500 páginas sobre o incidente indica que os controles do avião foram acionados de forma proposital para tirá-lo de sua rota, mas ainda não foi possível determinar o responsável.
Como o local da provável queda ainda não foi identificado, há quem insista em teorias da conspiração que vão de queda do avião controlada remotamente a abduções de seres extraterrestres.
Alguns especialistas da aviação acreditam que a explicação é que, de fato, um piloto experiente teria desviado o avião da rota. Por outro lado, a equipe de investigação declarou que não encontrou nada suspeito na história, treinamento e saúde mental do capitão e copiloto da aeronave. Se você considera essa história um grande mistério, talvez queira entender também a ocasião na qual NASA e EUA derrubaram um avião. Mas por quê?
Leia a matéria no Canaltech.
Venus keeps the strangest clock and calendar in the solar system. It takes about 243 Earth days to turn once on its axis, and only about 225 Earth days to travel all the way around the Sun. On Venus, in other words, the day is longer than the year. The planet finishes a lap of the Sun before it has finished a single rotation.
It gets stranger from there, and the figures are worth pulling apart, because two different “days” are hiding in this story.
The 243-day figure is the time Venus takes to spin once relative to the distant stars, what astronomers call a sidereal rotation. It is the true turn of the planet on its axis.
But a day in the everyday sense is the gap between one sunrise and the next, and on Venus that is a different and shorter span: about 117 Earth days. The two numbers disagree because Venus is moving around the Sun while it spins, and its spin is unusually slow, so the Sun’s position in the sky is set by a tug-of-war between the planet’s rotation and its orbit rather than by rotation alone. The result, according to NASA’s figures, is a solar day of roughly 117 Earth days. Sunrise to sunrise takes nearly four Earth months.
There is one more oddity, and it is the one most people have heard. On Venus the Sun comes up in the west and goes down in the east, the reverse of what it does here.
This is because Venus rotates backwards. Nearly every planet, Earth included, spins in the same direction it orbits, which is why our Sun rises in the east. Venus turns the other way, a motion called retrograde rotation, effectively almost upside down compared with its neighbours, its axis tipped close to 180 degrees. It is also the slowest-spinning planet in the solar system, which is part of why its day runs so long. From the surface, the Sun’s daily path would run the opposite way across the sky.
Why it spins like this is not settled. The leading ideas involve either a colossal ancient impact that flipped or reversed the planet, or the slow grinding action of solar tides on its massive atmosphere over billions of years. Both remain hypotheses.
Here the romantic image needs a caveat, because nobody on Venus would watch a crisp sun lift over a western horizon.
The planet is wrapped in a dense atmosphere of carbon dioxide topped with thick clouds of sulphuric acid, and almost no direct sunlight reaches the ground as a clear beam. A surface observer, if one could survive the 460-degree heat and crushing pressure, would experience a slow, dim brightening and fading of a uniformly glowing sky over those 117 days, rather than a disc rising at a point on the horizon. The direction of the Sun would be a smear of light, not a sunrise you could photograph.
That does not change the underlying mechanics. The Sun’s light still tracks east to west across that murky sky, just without a sharp Sun to mark it.
Put together, Venus runs on a schedule that breaks every habit Earth has taught us. The day outlasts the year. The Sun, such as it is, rises in the wrong place. And the time from one dim dawn to the next is counted in months, not hours.
None of these are quirks of measurement or rounding. They follow directly from a planet that turns slowly, backwards, beneath a sky that never clears, which is a fair summary of how thoroughly Venus refuses to behave like home.
The post A Venusian day is 243 Earth days long — longer than the planet’s entire 225-day year — and because Venus rotates backwards, the Sun would rise in the west and set in the east, though only once every 117 Earth days through its thick, cloud-choked sky. appeared first on Space Daily.
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Nature is often portrayed as a battlefield where every species competes for food, territory, and survival. Yet some of the most successful relationships in the natural world are built on cooperation.
Across oceans, forests, and deserts, animals regularly interact with members of other species in ways that benefit both sides. Interestingly, from an evolutionary perspective, this cooperation should be difficult. This is because animals belonging to different species do not share the same instincts, sensory abilities, or interests.
One animal may communicate through scent, another through movement, and a third through sound. Also, misunderstandings can be dangerous. A potential partner might instead become a competitor, a parasite, or even a predator.
“This gap in our understanding is noteworthy because animal interspecies cooperation combines features of multiple interaction types, sharing some challenges with broader mutualisms, such as cross-species communication and increased risk of harm or exploitation,” the authors of a new study note.
A new study examines how species overcome these obstacles through the exchange of information. The study authors argue that cues and signals help animals identify potential partners, assess their motivation to cooperate, and judge how reliable they are likely to be.
“Cues and signals are likely to be particularly crucial in animal interspecies cooperation, a specific form of mutualism that depends on real-time, interactive behavioural coordination to secure mutual benefit,” the study authors added.
By bringing together evidence from many forms of interspecies cooperation, the study provides a framework for understanding how communication helps make these unlikely partnerships possible.
The study emerged from a large interdisciplinary effort involving 58 researchers working across fields including animal behavior, ecology, evolution, anthropology, and linguistics.
Rather than focusing on a single species or ecosystem, the team examined evidence from a broad range of cooperative relationships to understand the common principles that allow different species to coordinate their actions.
What interested the researchers was not the details of any one partnership but a challenge common to all of them, which was uncertainty. Whenever individuals from different species interact, they must somehow determine whether cooperation is worth the risk.
The researchers found that many cooperative systems contain mechanisms that reduce this uncertainty. These can include visual displays, sounds, chemical compounds, body postures, or repeated behavioral patterns.
Regardless of the form they take, their purpose is similar—they provide information that allows one species to anticipate the actions of another.
Seen this way, communication functions less like a conversation and more like a mechanism for reducing uncertainty. Signals can reveal who a partner is, whether it intends to cooperate, and how predictable its behavior is likely to be. By making behavior more predictable, they reduce the risks that would otherwise discourage cooperation.
One example comes from the partnership between greater honeyguide birds and humans in parts of Africa. The birds use calls and behaviors that help direct people toward wild bees’ nests, while humans respond with their own vocal signals during the search. As a result, both sides gain access to resources they would struggle to obtain as efficiently on their own.
The study also explores how communication systems may evolve over time. The researchers distinguish between cues and signals. A cue provides information to another species but did not evolve specifically for communication.
A signal, in contrast, has been shaped by evolution because it influences how another organism responds. However, the study authors note, “signals can evolve from cues.”
The study points to interactions involving brightly colored cleaner fish on coral reefs as an example of how information can facilitate cooperation. Their distinctive appearance and behavior help client fish recognize them as cleaning partners rather than prey.
According to the researchers, characteristics that reliably convey useful information can become increasingly important if other species benefit from responding to them. Over time, natural selection may strengthen these interactions.
Individuals who provide clearer information gain more cooperative opportunities, while those who interpret the information more accurately gain greater benefits. The authors suggest that this process can lead to coevolution, with one species becoming better at providing information and the other becoming better at interpreting it.
In this way, what begins as an incidental cue can gradually develop into a more specialized signal that helps coordinate cooperation between species. The researchers also found that these communication systems are not always fixed. Some appear remarkably consistent, while others vary across environments and populations.
This flexibility suggests that communication between species can be shaped not only by evolution but also by local ecological conditions and, in some cases, learning.
According to the study authors, “animal interspecies cooperation provides a powerful opportunity to investigate the evolution of communication.”
By examining how species exchange information to coordinate their actions, the researchers argue that communication may be one of the hidden foundations of cooperation in nature.
By comparing interspecies cooperation with communication systems found within species and in other mutualistic relationships, the authors provide a broader framework for understanding how cooperation emerges and persists.
At the same time, the researchers emphasize that many forms of interspecies communication remain poorly understood. This is because most studies have focused on a relatively small number of well-known examples, leaving many species and ecosystems unexplored.
Future work will investigate how signals originate, how they vary across populations, and how communication systems can evolve between cooperating species.
For now, the study’s message is simple. Cooperation does not require animals to share a common language. It requires enough information for each partner to recognize, interpret, and respond to the other. In nature, this ability may be what transforms a risky encounter into a lasting partnership.
The study is published in the journal Animal Behavior.
Spotting and killing off cancer.
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When NASA’s Parker Solar Probe passed through the solar corona during perihelion encounters at the heliospheric current sheet, its instruments recorded energetic protons at energies far above what existing models of particle acceleration at that location could account for.
A team led by Mihir Desai at the Southwest Research Institute, with James Drake, Marc Swisdak, and Zhiyu Yin from the University of Maryland’s Institute for Research in Electronics and Applied Physics has published an analysis of those measurements in The Astrophysical Journal Letters, identifying magnetic reconnection at the heliospheric current sheet as the mechanism responsible. The proton energies detected were, in the study’s framing, approximately a thousand times greater than the available magnetic energy per particle that models of this process had predicted.
The finding matters for two reasons: it identifies a source of energetic particles close to the Sun that was not anticipated, and it raises questions about how far the existing understanding of reconnection-driven particle acceleration extends.
The heliospheric current sheet is a vast, warped surface in the solar wind where the Sun’s magnetic field reverses polarity. Parker crosses it during perihelion passes, when the spacecraft dips inside the corona. At those distances, the current sheet is narrower and more structured than it appears in the near-Earth solar wind, and the reconnection events occurring there have characteristics that instruments further from the Sun cannot resolve.
Within the exhaust region downstream of a reconnection event, where magnetic field lines have broken and rejoined and the released energy is being distributed into the surrounding plasma, Parker detected trapped protons at energies up to approximately 400 keV. The particles were confined within magnetic islands, structures that form within the reconnection exhaust as reconnected field lines roll up into closed loops. Magnetic island merging, as those loops interact and combine, appears to be the mechanism that accelerated the protons to the observed energies.
The thousand-fold discrepancy between what the models predicted and what Parker measured is the number that requires explanation. Reconnection as a particle accelerator was not a new idea: the process has been theorised to play a role in accelerating charged particles in a range of astrophysical environments. What was not predicted was that the energisation within near-Sun reconnection exhaust could reach this level through the island-merging pathway.
Current models of solar energetic particles, the high-speed charged particles that propagate through the solar system and can affect spacecraft and astronauts, have generally attributed the most energetic events to large-scale shocks: the driven shock fronts of coronal mass ejections, and the slower-building shocks of co-rotating interaction regions. Reconnection at the current sheet was considered a secondary contributor at best, capable of producing modest particle energies close to the Sun but not a major accelerator of the particles that eventually arrive as energetic storm particle events near Earth.
The Parker measurements suggest that picture needs revision. The magnetic island merging mechanism Desai and colleagues identify can evidently produce proton populations at energies that challenge the boundary between what reconnection does and what shock acceleration does. Whether this source can explain a significant fraction of observed near-Earth energetic particle events, or whether it contributes mainly at energies and scales that remain confined close to the Sun, is a question the paper does not yet resolve.
A separate thread connects to the longstanding question of why the solar corona is so much hotter than the surface below it. The corona reaches temperatures of several million degrees Celsius while the photosphere sits at around 5,500°C. The energy source sustaining that gradient has not been fully identified. Reconnection, along with wave heating, is one of the leading candidates.
If reconnection at the current sheet is producing particles at the energies Parker measured, it is also depositing energy into the surrounding plasma at rates that may be higher than the models assumed. That does not resolve the corona heating problem, but it shifts the accounting. The energy going into particle acceleration through magnetic island merging is energy that must come from somewhere in the magnetic field, and tracing it may tighten the constraints on how much reconnection contributes to coronal heating overall.
Drake and Swisdak contributed the reconnection theory component of the analysis. The collaboration between the observational data from Parker and the theoretical modelling capacity at the University of Maryland is the structure the paper’s analysis rests on.
Parker Solar Probe has now completed more than two dozen perihelion passes, with each close approach yielding data at distances and speeds no prior mission could reach. The heliospheric current sheet crossings that provided the data for this paper are repeatable: Parker will continue to encounter the current sheet during future perihelia, allowing the team to look for the magnetic island signature in additional events and test whether the particle energies observed here hold up as a consistent feature rather than a single anomaly.
Solar Orbiter, the European Space Agency mission operating in coordination with Parker, offers complementary measurements at somewhat greater distances. Comparing what the two spacecraft measure of the same particle populations as they propagate outward from the Sun will help establish which features originate close to the source and which are modified by the intervening solar wind. The energetic particle observations that puzzled researchers in the pre-Parker era now have a candidate mechanism. Whether that mechanism accounts for a large or small fraction of what actually reaches Earth remains the open question.
The post NASA’s Parker Solar Probe flew in and out of the solar corona and found a source of high-energy particles that no existing model had predicted appeared first on Space Daily.
Vitamin B12 is needed in only trace amounts, yet its absence can have far-reaching effects. Two micrograms is an almost unimaginably small amount. It weighs less than a tiny fragment of a grain of table salt. Yet adults need only around this amount of vitamin B12 each day, depending on the guideline used, to support [...]The Murchison meteorite is, by every available measure, one of the more scientifically valuable single rocks ever to fall on the planet. The fireball that delivered it streaked across the sky above the Goulburn Valley in southeastern Australia on a Sunday morning in September 1969, broke apart at high altitude, and scattered fragments across a roughly 35-square-kilometre area of farmland. One piece punched through the roof of a hay shed. The local dairy farmers who recovered most of the fragments over the following weeks sold the bulk of them to museums and universities, with the largest single collection now held by the Field Museum of Natural History in Chicago. Approximately 80 kilograms of the original 100-kilogram fall is currently held in scientific collections around the world. Over the subsequent five decades, Murchison has been examined more intensively than almost any other meteorite — yielding more than 70 distinct amino acids (including some that do not occur in any known terrestrial biology), sugars including ribose (the backbone of RNA), and several of the nucleobases that make up the building blocks of DNA. The rock has been at the centre of multiple revisions to scientific understanding of how organic chemistry distributes itself through the early solar system.
According to NBC News’s coverage of the 2020 Heck et al. paper on presolar grains in Murchison, the team published its dating results in the Proceedings of the National Academy of Sciences in January 2020. The analysis used a technique called cosmic-ray exposure dating, which Heck described with an unusually accessible analogy: cosmic rays — high-energy particles that constantly stream through the galaxy — interact with solid matter and produce new elements at a roughly constant rate. The longer a particle of matter has been drifting through space exposed to cosmic rays, the more of these new elements accumulate inside it. “I compare this with putting out a bucket in a rainstorm,” Heck told reporters at the time. “Assuming the rainfall is constant, the amount of water that accumulates in the bucket tells you how long it was exposed.” Applying this method to 40 large silicon-carbide grains extracted from the Murchison fragments, the Heck team was able to estimate how long each individual grain had been drifting through interstellar space before being incorporated into the asteroid that eventually fell to Earth.
The grains the Heck team dated are called presolar grains — solid particles that formed in the atmospheres of dying stars before the solar system existed, drifted through the interstellar medium for hundreds of millions or billions of years, and were then incorporated into the molecular cloud from which the Sun and planets eventually condensed. As reported in Sci.News’s coverage of the same paper, the typical formation environment for the silicon-carbide grains examined by the Heck team was the slowly-expanding atmosphere of an asymptotic giant branch (AGB) star — a red giant in the late stages of its evolution, shedding its outer layers into space at a rate of roughly one solar mass every hundred thousand years. The carbon, silicon, and other elements in the stellar atmosphere condense as the gas cools and expands, forming microscopic dust grains that are then carried outward by the stellar wind into the surrounding interstellar medium.
Most of these grains, once released into space, are eventually destroyed by some combination of supernova shock waves, radiation, and chemical reprocessing within the molecular clouds where new stars form. A small fraction survive intact for billions of years, drifting through the galaxy as part of the general inventory of interstellar dust. When a new solar system begins to form by gravitational collapse of a dense region of interstellar gas, this dust is incorporated into the early protoplanetary disc — and the heat and chemistry of solar system formation typically destroys or substantially alters most of it. The grains that survive intact through the entire formation process do so because they are extraordinarily durable (silicon carbide is one of the hardest materials in nature) and because they are quickly incorporated into the deep interiors of primitive asteroids that never undergo significant thermal processing. Murchison’s parent body was one such asteroid. The grains inside the Murchison fragments are, in a literal sense, time capsules from before the solar system existed.
The headline figure from the Heck team’s analysis — that the oldest grains are approximately 7 billion years old, predating the solar system by approximately 2.5 billion years — captures the extreme of the distribution rather than the average. Per ScienceDaily’s coverage of the Field Museum announcement, the full age distribution of the 40 grains was substantially more informative than the single extreme number suggests. Approximately 60 percent of the grains formed between 4.6 and 4.9 billion years ago — in the few hundred million years immediately preceding the formation of the solar system. Approximately 10 percent formed more than 5.6 billion years ago. A small number formed at the extreme end, around 7 billion years ago. Every grain examined was, by the cosmic-ray exposure dating, older than the 4.6-billion-year-old Sun. This is what made them presolar.
The distribution itself carries scientific weight beyond the individual grain ages. The clustering of a substantial fraction of grains in a narrow age band suggests that an unusual number of stars in the Milky Way galaxy formed, lived their full life cycles, and died during a specific epoch several billion years before the Sun ignited — a “burst” of star formation that produced an unusually large population of dying stars whose outflows seeded the surrounding interstellar medium with the dust that would later contribute to the formation of the solar system. The Heck team’s interpretation, drawing on the age distribution, is that this burst occurred approximately 7 billion years ago. The implication is that the Sun and the planets formed, several billion years later, from a galactic environment that had been substantially enriched with material from this earlier generation of stars.
As reported by Malay Mail’s coverage of the age distribution, the broader reason presolar grains can only be found in meteorites — never in any rock of terrestrial origin — is that every piece of solid material that contributed to Earth’s formation has subsequently been heated, melted, recrystallised, or otherwise reprocessed by the geological activity of the planet itself. Plate tectonics has churned the entire crust through the mantle and back at least once. Volcanism has melted and re-erupted vast quantities of material. Even the oldest rocks on Earth, found in places like the Acasta Gneiss Complex in northern Canada, are at most 4.0 to 4.2 billion years old — substantially younger than the planet itself, and far younger than the presolar grains preserved inside primitive meteorites.
The Murchison meteorite, in this respect, occupies a peculiar epistemological position. It is the closest available physical sample of the early solar system, but it is also a sample of the pre-solar-system galaxy that produced the early solar system. The grains inside it are older than anything that can be found by digging downward through the rocks of Earth, by any depth or any drilling technology. They are, in essence, a sample of the chemistry of the Milky Way at a moment several billion years before any of the familiar features of the current solar system existed. The fragments collected by Australian dairy farmers in 1969 and sent to museums in Chicago and elsewhere have turned out to contain, embedded in their carbonaceous matrix, a small but real sample of stardust from stars that finished burning before the Sun began.
The post In September 1969, a 100-kilogram space rock exploded in the sky above Murchison, Australia — and 50 years later, scientists analyzing dust grains buried inside the meteorite found particles between 5 and 7 billion years old, formed in the dying outer layers of stars that lived and died long before our Sun was born, in what remains the oldest solid material ever identified on the surface of the Earth appeared first on Space Daily.
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