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China has unveiled the design of a new reusable shuttle to take cargo to and from the country's space station.

The Haolong space shuttle is being developed by the Chengdu Aircraft Design and Research Institute under the state-owned Aviation Industry Corporation of China (AVIC). It is one of two winning projects stemming from a call for proposals from China's human spaceflight agency, CMSA, to develop low-cost cargo spacecraft.

China currently uses its robotic Tianzhou spacecraft to send cargo to the Tiangong space station. But, taking a leaf out of NASA's book to encourage commercial resupply options for the International Space Station, CMSA wanted new, low-cost ideas that can also return experiments and other cargo to Earth, unlike the Tianzhou, which burns up on reentry.

Haolong will launch atop of a rocket and land horizontally on Earth on a runway. The space shuttle measures 32.8 feet (10 meters) long and 26.2 feet (8 m) wide, and weighs less than half of the Tianzhou capsule, which has a mass of up to 31,000 pounds (14,000 kilograms). The winged spacecraft is now in the engineering flight verification phase, meaning its design and systems are under review before being built.

(Update: the video seems not to work for me, but I found the right video on youtube showing how a flight would work.)

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spoilerA pig in Oregon has tested positive for the H5N1 bird flu virus, the Agriculture Department said Wednesday. It's the first time the virus has been detected in swine in the United States.

Test results are pending for two other pigs found on the farm in Crook County, Oregon, the USDA said, while two others tested negative.

The pig that tested positive didn't show signs of illness.

The five pigs were tested for H5N1 out of an abundance of caution, officials said, and "because of the presence of H5N1 in other animals on the premises."

The case is concerning as pigs can become infected with both bird and human viruses at the same time, which can give rise to mutated strains that can more easily infect humans.

Officials said there are no concerns about the safety of the nation's pork supply.

The farm is noncommercial, the USDA said, and the animals weren’t intended for the commercial food supply. Additionally, the farm has been quarantined to prevent the spread of the virus. Sheep, goats and other animals on the farm are under surveillance, officials said.

The update comes as the H5N1 virus continues to spread rapidly among dairy cows across the country.

The bird flu outbreak in dairy cows has infected 387 herds across 14 states so far, according to the Centers for Disease Control and Prevention.

Since March, there have been a total of 36 human cases, the majority of whom had direct contact with farm animals, such as dairy cows and poultry. Most cases have been reported in California and Colorado.

All of the patients who had tested positive have recovered. Most had redness and discharge from the eyes, and some had mild respiratory symptoms.

There is no indication yet that this strain of flu virus is mutating in ways that would allow it to spread easily among people. Last week, the CDC released results of a monthslong investigation that found no evidence of bird flu spreading from human to human.

It's unclear how the pig in Oregon was exposed to bird flu, although earlier this month state officials detected the virus in poultry on the farm.

Officials said livestock and poultry on the farm shared water sources, housing and equipment. In other states, officials said, the combination has enabled transmission between species.

The pig that tested positive was euthanized so investigators can do additional testing to determine whether it was truly infected with the virus, or perhaps whether it had simply sniffed up some particles that contained H5N1.

“This could be environmental contamination in the nose,” said Michael Osterholm, an infectious disease expert and director of the Center for Infectious Disease Research and Policy at the University of Minnesota. “I commend them for doing the necropsy. It’s really important to understand — is there evidence of real infection?”

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submitted 2 weeks ago* (last edited 2 weeks ago) by [email protected] to c/[email protected]
 
 

Hey DWEEBS, hold on to your butts because BIRD POSTING is BACK and ready to get IN YOUR FACE to the EXTREME! Sit the fuck down and try not to SHIT YOURSELF in excitement.

The crested auklet (Aethia cristatella) is described by Cornell Ornithology as:

Dumpy, dark alcid with pale eyes; very small, only slightly larger than a sparrow.

DUMPY?!? Ex-fucking-scuse me, this is who you're calling dumpy?!

Magestic, radiant, moisturized. Definitely not dumpy!

These fashion illiterate ornithologists go on to further state:

Breeding birds are dark gray-black overall, with a droopy forward-arching crest and a bright orange bill with an uptilted gape which gives them a maniacally grinning appearance.

I don't know what you mean.

Crested Auklets are sea birds that spend most their lives on the Alaskan and Japanese Pacific ocean, only coming into land at mating season.

They eat squid, planktonic crustaceans, comb jellies, and worms. Ninety percent of their diet is copepods and other planktonic crustaceans. They catch their prey by pursuit-diving. Resting on the ocean’s surface, they abruptly tilt forward, opening their wings parallel to their body with the feathers oriented backwards. Keeping their wings only partially open to reduce drag, they dive. Underwater they beat their wings, “flying” at speeds about equivalent to that of a human’s walking speed.

Gotta feed that dumpy

Crested Auklets are socially monogamous. They do not maintain their pair bonds at sea but meet at the nesting site each year to reform their bond. Mating usually takes place at sea near the nesting site. Nesting colonies range from 10-20 pairs to up to a thousand birds. These birds prefer secluded areas safe from predators for nesting and eggs are usually laid on bare rock in crevices on rocky cliffs.

Normally, one egg is laid each season. The eggs incubate for 34-41 days with both the male and female sharing responsibilities for the incubation and feeding of the hatchlings. Parents carry plankton to the chick in a pouch under their tongue. Parental duties end when the chicks fledge when about 35 days old. They fly directly to sea from the nesting colonies several meters (feet) offshore.

Crested Auklets are highly social, staying in large groups at sea, and nesting in large colonies. They fly close to the surface of the water with continuous whirling wing beats.

Silent at sea, these birds are the nosiest of the auklets when in the breeding colonies, vocalizing with groans, low hoots, grunts, and barking calls.

Well adapted to life at sea, their feathers are waterproof to keep out the cold water in which they dive to feed. Their stiff wings help them to “fly” underwater in search of prey. Their bones are very strong to withstand the underwater pressure. They are able to store oxygen in their body tissues and to use anaerobic respiration. Both of these adaptations enable them to make long dives.

Crested Auklets use scent to communicate socially. During the breeding season each of the male-female pair produces a strong tangerine scent in the nape of the ruff feathers of their neck. The scent is attractive to their mate and also signals their readiness to breed. Both partners perform a “ruff-sniff” display in which they press their bill and face into the ruff feathers of their breeding partner. This scent is strong enough to be detected by humans some distance from the breeding colonies.

SHNEEEEEF monogamy

Estimates of their lifespan vary from 7 to 25 years

The Most Stylish Bird in the North Pacific | Frozen Planet II | <- a cute little segment on them being goofy during mating season

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to celebrate this occasion, i'll ask pou all a fun science question. what is your top 3 elements? I think mine are 1. Rubidium 2. Strontium 3. Beryllium (you can probably tell i love the representative metals)

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submitted 1 month ago* (last edited 1 month ago) by [email protected] to c/[email protected]
 
 

An interesting paper I found during my studies. Here's the abstract for those without the time to read a whole ass paper:

Abstract: While invertebrates make up the majority of animal species, their welfare is overlooked compared to the concern shown to vertebrates. This fact is highlighted by the near absence of regulations in animal research, with the exception of cephalopods in the European Union. This is often justified by assumptions that invertebrates do not experience pain and stress while lacking the capacity for higher order cognitive functions. Recent research suggests that invertebrates may be just as capable as vertebrates in experiencing pain and stress, and some species display comparable cognitive capacities. Another obstacle is the negative view of invertebrates by the public, which often regards them as pests with no individual personalities, gastronomic entities, or individuals for scientific experimentation without rules. Increasingly, studies have revealed that invertebrates possess individual profiles comparable to the personalities found in vertebrates. Given the large economic impact of invertebrates, developing certain attitude changes in invertebrate welfare may be beneficial for producers while providing higher welfare conditions for the animals. While the immense number and type of species makes it difficult to suggest that all invertebrates will benefit from increased welfare, in this review we provide evidence that the topic of invertebrate welfare should be revisited, more thoroughly investigated, and in cases where appropriate, formally instituted

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Preprint of a new paper examining the material conditions that give rise to internationally recognized scientists just came out. The authors argue that if we were actually recognizing and nurturing scientific talent, we'd expect the family income distribution of Nobel laureates to be roughly normal (i.e. most Nobel winners would come from families with incomes around the 50th percentile). Their results very much do not bear this out: the average Nobel winner grew up in a household in the about the 90th percentile of income no matter where they grew up, with disproportionately large numbers coming from the 95th percentile and up. This strongly suggests that academic achievement, especially at the highest levels, is not a meritocracy, but rather limited by the material conditions of birth.

shocked-pikachu I know, but the size of the effect is really staggering.

Paper here

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https://www.swpc.noaa.gov/products/alerts-watches-and-warnings

Space Weather Message Code: WATA99

Serial Number: 8

Issue Time: 2024 Oct 09 1233 UTC

WATCH: Geomagnetic Storm Category G4 or Greater Predicted

Highest Storm Level Predicted by Day:

Oct 10: G4 (Severe) Oct 11: G4 (Severe) Oct 12: G1 (Minor)

THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

NOAA Space Weather Scale descriptions can be found at

www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 45 degrees Geomagnetic Latitude. Induced Currents - Possible widespread voltage control problems and some protective systems may mistakenly trip out key assets from the power grid. Induced pipeline currents intensify.

Spacecraft - Systems may experience surface charging; increased drag on low earth orbit satellites, and tracking and orientation problems may occur.

Navigation - Satellite navigation (GPS) degraded or inoperable for hours.

Radio - HF (high frequency) radio propagation sporadic or blacked out.

Aurora - Aurora may be seen as low as Alabama and northern California.

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We tend to think of agriculture as a human innovation. But insects beat us to it by millions of years. Various ant species cooperate with fungi, creating a home for them, providing them with nutrients, and harvesting them as food. This reaches the peak of sophistication in the leafcutter ants, which cut foliage and return it to feed their fungi, which in turn form specialized growths that are harvested for food. But other ant species cooperate with fungi—in some cases strains of fungus that are also found growing in their environment.

Genetic studies have shown that these symbiotic relationships are highly specific—a given ant species will often cooperate with just a single strain of fungus. A number of genes that appear to have evolved rapidly in response to strains of fungi take part in this cooperative relationship. But it has been less clear how the cooperation originally came about, partly because we don't have a good picture of what the undomesticated relatives of these fungi look like.

Now, a large international team of researchers has done a study that traces the relationships among a large collection of both fungi and ants, providing a clearer picture of how this form of agriculture evolved. And the history this study reveals suggests that the cooperation between ants and their crops began after the mass extinction that killed the dinosaurs, when little beyond fungi could thrive.

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Sputnik 1 (/ˈspʌtnɪk, ˈspʊtnɪk/, ‹See Tfd›Russian: Спутник-1, Satellite 1) was the first artificial Earth satellite. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957 as part of the Soviet space program. It sent a radio signal back to Earth for three weeks before its three silver-zinc batteries became depleted. Aerodynamic drag caused it to fall back into the atmosphere on 4 January 1958. The world's first observation was made at the school observatory in Rodewisch (Saxony).

It was a polished metal sphere 58 cm (23 in) in diameter with four external radio antennas to broadcast radio pulses. Its radio signal was easily detectable by amateur radio operators, and the 65° orbital inclination made its flight path cover virtually the entire inhabited Earth.

The satellite's success was unanticipated by the United States. This precipitated the American Sputnik crisis and triggered the Space Race, part of the Cold War. The launch was the beginning of a new era of political, military, technological, and scientific developments. The word sputnik is Russian for satellite when interpreted in an astronomical context; its other meanings are spouse or traveling companion.

Tracking and studying Sputnik 1 from Earth provided scientists with valuable information. The density of the upper atmosphere could be deduced from its drag on the orbit, and the propagation of its radio signals gave data about the ionosphere.

Sputnik 1 was launched during the International Geophysical Year from Site No.1/5, at the 5th Tyuratam range, in Kazakh SSR (now known as the Baikonur Cosmodrome). The satellite traveled at a peak speed of about 8 km/s (18,000 mph), taking 96.20 minutes to complete each orbit. It transmitted on 20.005 and 40.002 MHz, which were monitored by radio operators throughout the world. The signals continued for 22 days until the transmitter batteries depleted on 26 October 1957. On 4 January 1958, after three months in orbit, Sputnik 1 burned up while reentering Earth's atmosphere, having completed 1,440 orbits of the Earth, and travelling a distance of approximately 70,000,000 km (43,000,000 mi).

Megathreads and spaces to hang out:

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Links To Resources (Aid and Theory):

Aid:

Theory:

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comrade-fly

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submitted 1 month ago* (last edited 1 month ago) by [email protected] to c/[email protected]
 
 

From the book The Machinery of Life by David S. Goodsell. You can read about the artist's process here.

This is an illustration of the first stage of the central dogma of molecular biology, often stated simplistically as "DNA makes RNA, and RNA makes protein". Our DNA stores the blueprints for the unimaginably vast array of self-assembling nanomachines that make our body work, which are called proteins. Once a protein is made, it does not propagate any information back to DNA; DNA alone encodes the genome. However, it is possible for RNA to modify DNA. This is how HIV installs itself as a rootkit in the cell, which will be covered in a future post.

The nucleus is the cell's library, storing the delicate strands of DNA and protecting them from the rigors of the cytoplasm. Much of the DNA is wrapped around histone proteins to form small nucleosomes (yellow four-legged proteins) that compact and protect the DNA. When the DNA is needed, it is unwrapped, unwound, and read by RNA polymerase (large orange protein engulfing the yellow strand) to create a messenger RNA (thin purple rope). The RNA molecules are then processed: capping enzymes protect one end and polyadenylate polymerase adds a repeated string of adenine nucleotides to the other end, which are then protected by the polyadenylate binding protein. Our RNA must also be edited by large splicosome complexes (large light purple protein) to remove intron regions that do not encode proteins. Once the RNA is properly edited, it is delivered out of the nucleus through nuclear pore complexes (large green structure). These pores span the double-layered nuclear membrane and control the traffic of a diverse collection of importin proteins (purple protein traversing the large green structure), which carry other molecules in and out. The nuclear membrane is strengthened inside by criss-crossed layers of lamin protein filaments (in blue) (1,000,000 X)

Here is the zoomed-out context for this illustration; it shows the leftmost part of the rectangular colored box in this human blood plasma cell (10,000 X):

Future posts will move from left to right along this cross section, following the stages of the central dogma.

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submitted 1 month ago* (last edited 1 month ago) by [email protected] to c/[email protected]
 
 

Taken from the book The Machinery of Life by David S. Goodsell

As we all know, the mitochondria is the powerhouse of the cell.

Unlike simpler bacterial cells, our cells are filled with compartments that perform different duties. ATP synthesis is the primary task performed by the mitochondria, shown here in cross-section. The enzymes of the citric acid cycle (purple & blue) are found in the innermost space and the folded inner membrane provides the necessary separation of spaces needed to create the electrochemical gradient that powers ATP synthase (green mushroom shape). This membrane is one of the most protein-concentrated membranes found in our cells: by some estimates, three quarters of the membrane is composed of protein, with just enough lipid to hold it together. Compare this illustration with the illustration of Escherichia coli in this previous post, and notice that the mitochondrion includes very similar machinery for protein synthesis, complete with DNA, RNA, and ribosomes. It does not make all of its own proteins, however, and some must be transported from the cytoplasm by specialized transport proteins (light green crown shape) in the inner and outer membranes (1,000,000 X)

More on the advanced compartmentalization of human cells and the odd origin of mitochondria:

The human body is composed of trillions of cells. Just like a bacterial cell, each one of our cells (with a few exceptions) has DNA, polymerases, and ribosomes for building proteins based on genomic information. Each cell is filled with a collection of enzymes for making and breaking the many molecules needed for growth and energy production. Each cell is surrounded by a sturdy cell membrane filled with channels, pumps, and sensors. Each of our cells, however, is much larger and far more complex than a bacterial cell. Where bacteria are built to be fast and efficient, our cells are made to perform complex and specific tasks, and they are made to last and perform these tasks for years.

By looking at the similarities and differences between bacterial cells and animal cells, scientists have discovered that a breakthrough occurred in the evolution of life about 1.5 billion years ago. Simple, bacteria-like cells had probably been around for at least 2 billion years, and most of the basic molecular machinery of life had been perfected. Then, a new design of the cell body appeared: larger cells filled with many small, separate compartments, each surrounded by its own watertight membrane. The proliferation of these new cells signaled a major break in the evolution of cells, and in the years since then, two distinct family lines have evolved. The simple cells, with their molecular machinery jumbled together in one compartment, are the distant ancestors of the bacteria and archaebacteria. The new compartmented cells gave rise to all other forms of life, including protozoa, fungi, plants, and animals.

Surprisingly, when we look under the microscope, some of these compartments look similar to whole bacterial cells. The mitochondria in each of our cells have a similar shape, size, and composition as an Escherichia coli cell. For instance, mitochondria are surrounded by two membranes. The outer membrane is studded with proteins reminiscent of bacterial porins. The inner membrane, pleated and folded in mitochondria, is filled with proteins of transport and energy production similar to the bacterial proteins. Even more surprising, when you look inside a mitochondrion, it has its own DNA, transfer RNA, and ribosomes, all busily constructing mitochondrial proteins. These remarkable similarities have prompted a theory of the origin of mitochondria (and chloroplasts) that is now widely accepted. It is thought that a bacterial cell took to living inside another cell in the distant past, perhaps entering as a parasite or perhaps surviving the process of being eaten. The bacterium continued to live in this comfortable, sheltered environment, living and reproducing inside the cell. Gradually, both the engulfed cell and the cellular host became increasingly reliant on each other, dividing up the tasks of living. Today, our mitochondria continue to divide and reproduce inside our cells, but they rely on the rest of the cell for many of their essential proteins and nutrients.

Here is a zoomed-out view (10,000 X) of a blood plasma cell under a microscope; the topmost box shows this post's headline illustration in context. The sheer scale of each ordinary human cell is incredible! And we have trillions of them!

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To make solar power viable, we need a solution for overnight energy storage.

Batteries are complicated.

Do you know what isn't? Water go up. stonks-up

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submitted 1 month ago* (last edited 1 month ago) by [email protected] to c/[email protected]
 
 

Source: The Machinery of Life by David S. Goodsell

When we look closely at an Escherichia coli cell, we observe a bustle of organized activity. This illustration shows a portion of a cell magnified to where individual molecules may be seen. Only the large biomolecules are shown, including proteins, nucleic acids, polysacchandes, and lipid membranes. The spaces in between are filed with water, sugars, nucleotides, amino acids, metal ions and many other small molecules, as shown below (1,000,000 X)

Water and Small Molecules This illustration shows a small portion of the cell at a higher magnification, showing the crowding of small molecules between the larger proteins and nucleic acids. Amino acids, sugars, ATP, and many other small organic molecules are shown in pink. Metal ions are shown in bright red, phosphate ions are in yellow and orange, and chloride ions are in green. Al of the remaining space is filled with water molecules, colored turquoise (5,000,000 X)

Here's the illustration in a larger context:

Cellular Propellers

The small size of Escherichia coli cells has a profound effect on the way that they interact with their surroundings. For them, gravity is not the overwhelming force that it is in our lives. Instead, the constant press of surrounding water is far more important. At small scales, water is not the flowing liquid that it is to us. The surface tension of water is a familiar example: small insects can skate along the surface of a pond, but if we try, the weight of our enormous bodies overwhelms the gentler forces of water and we plunge to the bottom. For cells, these differences are even greater. Cells live in a world of thick, viscous water, almost oblivious to gravity. When moving from place to place, most of their energy is spent trying to push through the gooey liquid, not in lifting their weight up from the ground.

For example, Howard Berg presented a surprising observation in his 1976 lecture "Life at Low Reynolds Number." Escherichia coli cells swim using long corkscrew-shaped flagella, which act like propellers. The cells push their way through the water, typically moving about 30 um/s (30 um is 10 or 15 times the length of the cell). But, when they stop turning the flagella, they don't keep coasting along the way a ship or submarine would. Instead, the surrounding water instantly stops them in less than the diameter of a water molecule.

The flagellar motor is one of the wonders of the biomolecular world. The motor spans the entire cell wall, rotating at speeds of up to 18,000 revolutions per minute. Each rotation is powered by the flow of about 1000 hydrogen ions across the inner membrane. Amazingly, the motor can turn the flagellum in either direction, clockwise or counterclockwise, on demand. When it turns in one direction, all of the flagella on the cell get tangled into a bundle, and together they propel the cell through the surrounding water. If the motor switches direction, however, the flagella separate and flail in different directions, causing the cell to stop and tumble in place.

Bacteria are faced with a serious problem with navigation. Since they are so tiny, they have no way to aim themselves in the right direction. A bacterial cell can't look at a distance and see what direction food lies. Instead, Escherichia coli cells use an effective combination of the swimming and tumbling properties of their flagella. Each cell uses an array of sensors to determine the level of food in the immediate vicinity. Then it swims in a random direction, and measures the level of nutrients there. If the levels are increasing, it keeps swimming in that direction, since things are getting better. If not, the sensory array sends a signal to the flagellar motor, telling it to reverse direction. This causes the cell to tumble, picking a new (and hopefully better) direction to swim. In the rich, watery environment of our intestines, this almost random approach is adequate to keep the cell nourished.

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From The Machinery of Life by David S. Goodsell.

ATP synthase is a molecule-sized generator that converts electrochemical energy into chemical energy. It is composed of two rotary motors connected together by an asymmetric axle. Flow of hydrogen ions through the bottom motor, which is embedded in a membrane, turns the large cylindrical rotor. This is connected to the axle, forcing it to turn inside the second motor at the top. With each turn, the axle distorts the subunits in the upper motor, catalyzing a reaction that makes the unstable phosphate-phosphate bond in ATP (5,000,000 X)

ATP Synthase is incredibly cool because it is probably the closest thing our body has to an honest-to-god recognizable nanomachine as humans would conceive of it. It can pump & rotate in both directions! If there is an electrochemical gradient across the membrane it sits on, it can sap the potential energy of that gradient to synthesize ATP to store energy for later as it lets ions across the membrane. Alternatively, it can consume ATP to pump ions in the opposite direction, creating an electrochemical gradient itself! There are a lot of cool animations you can find online, like this one: https://www.youtube.com/watch?v=kXpzp4RDGJI

How are electrochemical gradients created in the first place? Here's how plants do it with photosynthesis:

Cyclic Photophosphorylation Plants use the energy of light to make ATP, but they must go through many energy transformations to do it. The process starts with a photosystem protein that captures individual photons of light, and uses the energy of these photons to create high-energy electrons. These electrons then flow through several proteins, hopping through a chain of iron ions and copper ions and slowly losing their energy until they return to the photosystem, ready for another charge from light. As the electrons flow through the cytochrome b₆-f complex, they are used to power the pumping of hydrogen ions across the membrane, creating an electrochemical gradient. This gradient is finally used to power ATP synthase (5,000,000 X)

As always, remember that none of the things we are talking about have any willpower or desire - it's all just physics and random interactions and energy being moved around. Also remember that none of these systems were designed, but instead came into being through natural selection.

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A spider sputter-coated in gold to prepare it as a specimen for scanning electron microscopy.

A conductive coating is needed to prevent charging of a specimen with an electron beam in conventional SEM mode (high vacuum, high voltage).

This item was on display at the Australian Museum in Sydney, New South Wales, Australia.

—Wikipedia

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Illustration from The Machinery of Life by David S. Goodsell

Molecules constantly diffuse within the interior of cells, randomly bumping from place to place. This illustration shows several snapshots from a computer simulation of a protein and a sugar molecule diffusing inside a bacterial cell. The path of the protein is shown in blue and the path of sugar is shown in red. They start at opposite ends and explore much of the space inside before they reach each other.

I really like this because it illustrates, more than anything else, that our biomolecules don't "want" to do anything, go some place, bind somewhere; it's just physics and unbelievable quantities of random interactions. Excerpt from the text:

One basic thing remains the same at our size and at molecular size: the solidity of matter. At the scale of molecules, we do not need to worry too much about the odd things that happen with quantum mechanics: to a first approximation, molecules have a definite size and shape, and it is perfectly fine to imagine them bumping into each other and fitting together if the shapes match. If we look closely, their edges may be a bit fuzzy, but for most purposes, we can think of them as physical objects like tables and chairs.

Other properties, however, are very different when we enter the molecular world. For instance, molecules are so small that gravity is completely negligible. The motions and the interactions of biological molecules are completely dominated by the surrounding water molecules. At room temperature, a medium-sized protein travels at a rate of about 5 m/s (the speed of a fast runner). If placed alone in space, this protein would travel its own length in about a nanosecond (a billionth of a second). Inside the cell, however, this protein is battered from all sides by water molecules. It bounces back and forth, always at great speed, but takes a long time to get anywhere. When surrounded by water, this typical protein now requires almost a thousand times longer to move a protein-sized distance.

Imagine a similar situation in our world. You enter an airline terminal and want to reach a ticket window on the far side of the room. The distance is several meters—a distance comparable to your own size. If the room is empty, you dash across in a matter of seconds. But imagine instead that the room is crowded full of other people trying to get to their respective windows. With all the pushing and shoving, it now takes you 15 minutes to cross the room! In this time, you may be pushed all over the room, perhaps even back to your starting point a few times. This is similar (although molecules do not have a goal in mind) to the contorted path molecules take in the cell.

You might ask how anything ever gets done in this chaotic world. It is true that the motion is random, but it is also true that the motion is very fast compared to the motion in our familiar world. Random, diffusive motion is fast enough to perform most of the tasks in the cell. Each molecule simply bumps around until it finds the right place.

To get an idea of how fast this motion is, imagine a typical bacterial cell and place an enzyme at one end and a sugar molecule at the other. They will bump around and wander through the whole cell, encountering many molecules along the way. On average, though, it will only take about a second for those two molecules to bump into each other at least once. This is truly remarkable: this means that any molecule in a typical bacterial cell, during its chaotic journey through the cell, will encounter almost every other molecule in a matter of seconds. So as you are looking at the illustrations in this book, remember that static images give only a single snapshot of this teeming molecular world.

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The beginning of the article

Who knew a dragon’s tongue could be so long?

Astronomers announced last week that they had discovered a black hole spitting energy across 23 million light-years of intergalactic space. Two jets, shooting in opposite directions, compose the biggest lightning bolt ever seen in the sky — about 140 times as long as our own Milky Way galaxy is wide, and more than 10 times the distance from Earth to Andromeda, the nearest large spiral galaxy.

Follow-up observations with optical telescopes traced the eruption to a galaxy 7.5 billion light-years away that existed when the universe was less than half its current age of 14 billion years. At the heart of that galaxy was a black hole spewing energy equivalent to the output of more than a trillion stars.

“The Milky Way would be a little dot in these two giant eruptions,” said Martijn Oei, a postdoctoral researcher at the California Institute of Technology. Dr. Oei led the team that made the discovery, which was reported in Nature on Sept. 18 and announced on the journal’s cover with an illustration reminiscent of a “Star Wars” poster. The astronomers have named the black hole Porphyrion, after a giant in Greek mythology — a son of Gaia — who fought the gods and lost.

The discovery raises new questions of how such black holes could affect the evolution and structure of the universe.

Wikipedia: Porphyrion (radio galaxy)

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The Immune System Piercing a Bacterial Cell Wall

Our blood contains proteins that recognize and destroy invading cells and viruses. This illustration shows a cross section through a bacterial cell wall (lower half, in greens, blues and purples) being attacked by proteins in the blood serum (at the top, in yellows and oranges). Y-shaped antibodies begin the process by binding to the surface of the cell, and are in turn recognized by the six-armed protein at upper center. This begins a cascade of actions that ultimately lead to the formation of a membrane attack complex, shown here piercing the cell wall of the bacterium (1,000,000 X).

Source

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