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10 new things we’ve learned about death
If you don't want to know anything about your death, consider this your spoiler warning.
- For centuries cultures have personified death to give this terrifying mystery a familiar face.
- Modern science has demystified death by divulging its biological processes, yet many questions remain.
- Studying death is not meant to be a morbid reminder of a cruel fate, but a way to improve the lives of the living.
Black cloak. Scythe. Skeletal grin. The Grim Reaper is the classic visage of death in Western society, but it's far from the only one. Ancient societies personified death in a myriad of ways. Greek mythology has the winged nipper Thanatos. Norse mythology the gloomy and reclusive Hel, while Hindu traditions sport the wildly ornate King Yama.
Modern science has de-personified death, pulling back its cloak to discover a complex pattern of biological and physical processes that separate the living from the dead. But with the advent of these discoveries, in some ways, death has become more alien.
1) You are conscious after death
Many of us imagine death will be like drifting to sleep. Your head gets heavy. Your eyes flutter and gently close. A final breath and then… lights out. It sounds perversely pleasant. Too bad it may not be that quick.
Dr. Sam Parnia, the director of critical care and resuscitation research at NYU Langone Medical Center, researches death and has proposed that our consciousness sticks around while we die. This is due to brainwaves firing in the cerebral cortex — the conscious, thinking part of the brain — for roughly 20 seconds after clinical death.
Studies on lab rats have shown their brains surge with activity in the moments after death, resulting in an aroused and hyper-alert state. If such states occur in humans, it may be evidence that the brain maintains a lucid consciousness during death's early stages. It may also explain how patients brought back from the brink can remember events that took place while they were technically dead.
But why study the experience of death if there's no coming back from it?
"In the same way that a group of researchers might be studying the qualitative nature of the human experience of 'love,' for instance, we're trying to understand the exact features that people experience when they go through death, because we understand that this is going to reflect the universal experience we're all going to have when we die," he told LiveScience.
2) Zombie brains are a thing (kind of)
There is life after death if you're a pig...sorta. Image source: Wikimedia Commons)
Recently at the Yale School of Medicine, researchers received 32 dead pig brains from a nearby slaughterhouse. No, it wasn't some Mafia-style intimidation tactic. They'd placed the order in the hopes of giving the brains a physiological resurrection.
The researchers connected the brains to an artificial perfusion system called BrainEx. It pumped a solution through them that mimicked blood flow, bringing oxygen and nutrients to the inert tissues.
This system revitalized the brains and kept some of their cells "alive" for as long as 36 hours postmortem. The cells consumed and metabolized sugars. The brains' immune systems even kicked back in. And some samples were even able to carry electrical signals.
Because the researchers weren't aiming for Animal Farm with Zombies, they included chemicals in the solution that prevented neural activity representative of consciousness from taking place.
Their actual goal was to design a technology that will help us study the brain and its cellular functions longer and more thoroughly. With it, we may be able to develop new treatments for brain injuries and neurodegenerative conditions.
3) Death is not the end for part of you
Researchers used zebrafish to gain insights into postmortem gene expression. Image source: ICHD / Flickr
There is life after death. No, science hasn't discovered proof of an afterlife or how much the soul weighs. But our genes keep going after our demise.
A study published in the Royal Society's Open Biology looked at gene expression in dead mice and zebrafish. The researchers were unsure if gene expression diminished gradually or stopped altogether. What they found surprised them. Over a thousand genes became more active after death. In some cases, these spiked expressions lasted for up to four days.
"We didn't anticipate that," Peter Noble, study author and microbiology professor at the University of Washington, told Newsweek. "Can you imagine, 24 hours after [time of death] you take a sample and the transcripts of the genes are actually increasing in abundance? That was a surprise."
Gene expression was shown for stress and immunity responses but also developmental genes. Noble and his co-authors suggest this shows that the body undergoes a "step-wise shutdown," meaning vertebrates die gradually and not all at once.
4) Your energy lives on
Even our genes will eventually fade, and all that we are will become clay. Do you find such oblivion disheartening? You're not alone, but you may take solace in the fact that part of you will continue on long after your death. Your energy.
According to the first law of thermodynamics, the energy that powers all life continues on and can never be destroyed. It is transformed. As comedian and physicist Aaron Freeman explains in his "Eulogy from a Physicist":
"You want the physicist to remind your sobbing mother about the first law of thermodynamics; that no energy gets created in the universe, and none is destroyed. You want your mother to know that all your energy, every vibration, every Btu of heat, every wave of every particle that was her beloved child remains with her in this world. You want the physicist to tell your weeping father that amid energies of the cosmos, you gave as good as you got."
5) Near-death experiences may be extreme dreams
Near-death experiences come in a variety of styles. Some people float above their bodies. Some go to a supernatural realm and meet passed-on relatives. Others enjoy the classic dark-tunnel-bright-light scenario. One thing they all have in common: We don't know what's going on.
A study published in Neurology suggests near-death experiences stem from a type of sleep-wake state. It compared survivors who had near-death experiences with those who did not. The researchers found that people with near-death experiences were more likely to also undergo REM intrusions, states in which sleep intrudes upon wakeful consciousness.
"People who have near-death experiences may have an arousal system that predisposes them to REM intrusion," Kevin Nelson, professor at the University of Kentucky and the study's lead author, told the BBC.
It's worth noting that the study does have its limitations. Only 55 participants were interviewed in each group, and the results relied on anecdotal evidence. These highlight key difficulties in studying near-death experiences. Such experiences are rare and cannot be induced in a controlled setting. (Such a proposal would be a huge red flag for any ethics board.)
The result is sparse data opened to a lot of interpretation, but it is unlikely that the soul enjoys a postmortem romp. One experiment installed pictures on high shelves in 1,000 hospital rooms. These images would only be visible to people whose souls departed the body and returned.
No cardiac arrest survivor reported seeing the images. Then again, if they did manage to sever their fleshy fetters, they may have had more pressing matters to attend to.
6) Animals may mourn the dead too
Elephants form strong familial bonds, and some eye witness accounts suggest they may mourn the dead, too. Image source: Cocoparisienne / Pixabay
We're still not sure, but eye witness accounts suggest the answer may be yes.
Field researchers have witnessed elephants staying with the dead — even if the deceased is not from the same family herd. This observation led the researchers to conclude the elephants had a "generalized response" to death. Dolphins too have been seen guarding deceased members of their species. And chimpanzees maintain social routines with the dead, such as grooming.
No other species has been observed performing human-like memorial rituals, which requires abstract thought, but these events suggest animals possess a unique understanding of and response to death.
As Jason Goldman writes for BBC, "[F]or every facet of life that is unique to our species, there are hundreds that are shared with other animals. As important as it is to avoid projecting our own feelings onto animals, we also need to remember that we are, in an inescapable way, animals ourselves."
7) Who first buried the dead?
Anthropologist Donald Brown has studied human cultures and discovered hundreds of features shared by each and every one. Among them, every culture has its own way to honor and mourn the dead.
But who was the first? Humans or another hominin in our ancestral lineage? That answer is difficult because it is shrouded in the fog of our prehistorical past. However, we do have a candidate: Homo naledi.
Several fossils of this extinct hominin were discovered in a cave chamber at the Rising Star Cave system, Cradle of Humankind, South Africa. To access the chamber required a vertical climb, a few tight fits, and much crawling.
This led researchers to believe it unlikely so many individuals ended up there by accident. They also ruled out geological traps like cave-ins. Given the seemingly deliberate placement, some have concluded the chamber served as a Homo naledi graveyard. Others aren't so sure, and more evidence is needed before we can definitively answer this question.
8) Walking corpse syndrome
The medieval Danse Macabre fresco at the Holy Trinity Church in Hrastovlje, Solvenia. (Photo: Marco Almbauer/Wikimedia Commons)
For most of us, the line between life and death is stark. We are alive; therefore, we are not dead. It's a notion many take for granted, and we should be thankful we can manage it so effortlessly.
People afflicted with Cotard's syndrome don't see the divide so cleanly. This rare condition was first described by Dr. Jules Cotard in 1882 and describes people who believe they are dead, missing body parts, or have lost their soul. This nihilistic delusion manifests in a prevailing sense of hopelessness, neglect of health, and difficulty dealing with external reality.
In one case, a 53-year-old Filipino woman with Cotard's syndrome believed herself to smell like rotting fish and wished to be brought to the morgue so she could be with her kind. Thankfully, a regimen of antipsychotics and antidepressants improved her condition. Others with this debilitating mental disorder have also been known to improve with proper treatment.
9) Do hair and fingernails grow after death?
Nope. This is a myth, but one that does have a biological origin.
The reason hair and fingernails don't grow after death is because new cells can't be produced. Glucose fuels cell division, and cells require oxygen to break down glucose into cellular energy. Death puts an end to the body's ability to intake either one.
It also ends the intaking of water, leading to dehydration. As a corpse's skin desiccates, it pulls away from the fingernails (making them look longer) and retracts around the face (giving a dead man's chin a five-o'clock shadow). Anyone unlucky enough to exhume a corpse could easily mistake these changes as signs of growth.
Interestingly, postmortem hair and fingernail growth provoked lore about vampires and other creatures of the night. When our ancestors dug up fresh corpses and found hair growth and blood spots around mouths (the result of natural blood pooling), their minds naturally wandered to undeath.
Not that becoming undead is anything we need to worry about today. (Unless, of course, you donate your brain to the Yale School of Medicine.)
10) Why we die?
People who live to be 110 years old, called super-centenarians, are a rare breed. Those who live to be 120 rarer still. The longest-living human on record was Jeanne Calment, a Frenchwoman who lived an astounding 122 years.
But why do we die in the first place? Setting spiritual and existential responses aside, the simple answer is that nature is done with us after a certain point.
Success in life, evolutionarily speaking, is passing on one's genes to offspring. As such, most species die soon after their fecund days end. Salmon die soon after making their upriver trek to fertilize their eggs. For them, reproduction is a one-way trip.
Humans are a bit different. We invest heavily in our young, so we require a longer lifespan to continue parental care. But human lives outpace their fecundity by many years. This extended lifespan allows us to invest time, care, and resources in grandchildren (who share our genes). This is known as the grandmother effect.
But if grandparents are so useful, why is cap set at 100-some-odd years? Because our evolution did not invest in longevity beyond that. Nerve cells do not replicate, brains shrink, hearts weaken, and we die. If evolution needed us to hang around longer, maybe these kill switches would have been weeded out, but evolution as we know it requires death to promote adaptive life.
At this age, however, it is likely that our children may be entering their grandparent years themselves, and our genes will continue to be cared for in subsequent generations.
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- Dead bodies keep moving for more than a year after death, new study finds - Big Think ›
Evolution proves to be just about as ingenious as Nikola Tesla
- For the first time, scientists developed 3D scans of shark intestines to learn how they digest what they eat.
- The scans reveal an intestinal structure that looks awfully familiar — it looks like a Tesla valve.
- The structure may allow sharks to better survive long breaks between feasts.
Considering how much sharks are feared by humans, it is a bit of a surprise that scientists don't know much about the predators. For example, until recently, sharks were thought to be solitary creatures searching the seas for food on their own. Now it appears that some sharks are quite social.
Another mystery is how these prehistoric swimming and eating machines digest food. Although scientists have made 2D sketches of captured sharks' digestive systems based on dissections, there is a limit to what can be learned in this way. Professor Adam Summers at University of Washington's Friday Harbor Labs says:
"Intestines are so complex, with so many overlapping layers, that dissection destroys the context and connectivity of the tissue. It would be like trying to understand what was reported in a newspaper by taking scissors to a rolled-up copy. The story just won't hang together."
Summers is co-author of a new study that has produced the first 3D scans of a shark's intestines, which turns out to have a strange, corkscrew structure. What's even more bizarre is that it resembles the amazing one-way valve designed by inventor Nikola Tesla in 1920. The research is published in the journal Proceedings of the Royal Society B.
What a 3D model reveals
Video: Pacific spiny dogfish intestine youtu.be
According to the study's lead author Samantha Leigh, "It's high time that some modern technology was used to look at these really amazing spiral intestines of sharks. We developed a new method to digitally scan these tissues and now can look at the soft tissues in such great detail without having to slice into them."
"CT scanning is one of the only ways to understand the shape of shark intestines in three dimensions," adds Summers. The researchers scanned the intestines of nearly three dozen different shark species.
It is believed that sharks go for extended periods — days or even weeks — between big meals. The scans reveal that food passes slowly through the intestine, affording sharks' digestive system the time to fully extract its nutrient value. The researchers hypothesize that such a slow digestive process may also require less energy.
It could be that this slow digestion is more susceptible to back flow given that the momentum of digested food through the tract must be minimal. Perhaps that is why sharks evolved something so similar to a Tesla valve.
What is Tesla's valve doing there?
Above, a Tesla valve. Below, a shark intestine.Credit: Samantha Leigh / California State University, Domi
Tesla's "valvular conduit," or what the world now calls a "Tesla valve," is a one-way valve with no moving parts. Its brilliance is based in fluid dynamics and only now coming to be fully appreciated. Essentially, a series of teardrop-shaped loops arranged along the length of the valve allow water to flow easily in one direction but not in the other. Modern tests reveal that at low flow rates, water can travel through the valve either way, but at high flow rates, the design kicks in. According to mathematician Leif Ristroph:
"Crucially, this turn-on comes with the generation of turbulent flows in the reverse direction, which 'plug' the pipe with vortices and disrupting currents. Moreover, the turbulence appears at far lower flow rates than have ever previously been observed for pipes of more standard shapes — up to 20 times lower speed than conventional turbulence in a cylindrical pipe or tube. This shows the power it has to control flows, which could be used in many applications."
A deeper dive
Summers suggests the scans are just the beginning. "The vast majority of shark species, and the majority of their physiology, are completely unknown," says Summers, adding that "every single natural history observation, internal visualization, and anatomical investigation shows us things we could not have guessed at."
To this end, the researchers plan to use 3D printing to produce models through which they can observe the behavior of different substances passing through them — after all, sharks typically eat fish, invertebrates, mammals, and seagrass. They also plan to explore with engineers ways in which the shark intestine design could be used industrially, perhaps for the treatment of wastewater or for filtering microplastics.
It could fairly be said, though, that Nikola Tesla was 100 years ahead of them.
The non-contact technique could someday be used to lift much heavier objects — maybe even humans.
- Since the 1980s, researchers have been using sound waves to move matter through a technique called acoustic trapping.
- Acoustic trapping devices move bits of matter by emitting strategically designed sound waves, which interact in such a way that the matter becomes "trapped" in areas of particular velocity and pressure.
- Acoustic and optical trapping devices are already used in various fields, including medicine, nanotechnology, and biological research.
Sound can have powerful effects on matter. After all, sound strikes our world in waves — vibrations of air molecules that bounce off of, get absorbed by, or pass through matter around us. Sound waves from a trained opera singer can shatter a wine glass. From a jet, they can collapse a stone wall. But sound can also be harnessed for delicate interactions with matter.
Since the 1980s, researchers have been using sound to move matter through a phenomenon called acoustic trapping. The method is based on the fact that sound waves produce an acoustic radiation force.
"When an acoustic wave interacts with a particle, it exerts both an oscillatory force and a much smaller steady-state 'radiation' force," wrote the American Physical Society. "This latter force is the one used for trapping and manipulation. Radiation forces are generated by the scattering of a traveling sound wave, or by energy gradients within the sound field."
When tiny particles encounter this radiation, they tend to be drawn toward regions of certain pressure and velocity within the sound field. Researchers can exploit this tendency by engineering sound waves that "trap" — or suspend — tiny particles in the air. Devices that do this are often called "acoustic tweezers."
Building a better tweezer
A study recently published in the Japanese Journal of Applied Physics describes how researchers created a new type of acoustic tweezer that was able to lift a small polystyrene ball into the air.
Tweezers of Sound: Acoustic Manipulation off a Reflective Surface youtu.be
It is not the first example of a successful "acoustic tweezer" device, but the new method is likely the first to overcome a common problem in acoustic trapping: sound waves bouncing off reflective surfaces, which disrupts acoustic traps.
To minimize the problems of reflectivity, the team behind the recent study configured ultrasonic transducers such that the sound waves that they produce overlap in a strategic way that is able to lift a small bit of polystyrene from a reflective surface. By changing how the transducers emit sound waves, the team can move the acoustic trap through space, which moves the bit of matter.
Move, but don't touch
So far, the device is only able to move millimeter-sized pieces of matter with varying degrees of success. "When we move a particle, it sometimes scatters away," the team noted. Still, improved acoustic trapping and other no-contact lifting technologies — like optical tweezers, commonly used in medicine — could prove useful in many future applications, including cell separation, nanotechnologies, and biological research.
Could future acoustic-trapping devices lift large and heavy objects, maybe even humans? It seems possible. In 2018, researchers from the University of Bristol managed to acoustically trap particles whose diameters were larger than the sound wavelength, which was a breakthrough because it surpassed "the classical Rayleigh scattering limit that has previously restricted stable acoustic particle trapping," the researchers wrote in their study.
In other words, the technique — which involved suspending matter in tornado-like acoustic traps — showed that it is possible to scale up acoustic trapping.
"Acoustic tractor beams have huge potential in many applications," Bruce Drinkwater, co-author of the 2018 study, said in a statement. "I'm particularly excited by the idea of contactless production lines where delicate objects are assembled without touching them."
Australian parrots have worked out how to open trash bins, and the trick is spreading across Sydney.
- If sharing learned knowledge is a form of culture, Australian cockatoos are one cultured bunch of birds.
- A cockatoo trick for opening trash bins to get at food has been spreading rapidly through Sydney's neighborhoods.
- But not all cockatoos open the bins; some just stay close to those that do.
Dumpster-diving trash parrots
In a study about these smart birds just published in Science, researchers define animal culture as "population-specific behaviors acquired via social learning from knowledgeable individuals."
Co-lead author of the study Barbara Klump of the Max Planck Institute of Animal Behavior in Konstanz, Germany says, "[C]ompared to humans, there are few known examples of animals learning from each other. Demonstrating that food scavenging behavior is not due to genetics is a challenge."
An opportunity presented itself in a video that co-author Richard Major of the Australian Museum shared with Klump and the other co-authors. In the video, a sulphur-crested cockatoo used its beak to pull up the handle of a closed garbage bin — using its foot as a wedge — and then walked back the lid sufficiently to flip it open, exposing the bin's edible contents.
Major has been studying Cacatua galerita for 20 years and says, "Like many Australian birds, sulphur-crested cockatoos are loud and aggressive." The study describes them as a "large-brained, long-lived, and highly social parrot." Says Major, "They are also incredibly smart, persistent, and have adapted brilliantly to living with humans."(Research regarding some of the ways in which wild animals adapt to the presence of humans has already produced some fascinating results and is ongoing.)
Clever cockie opens bin - 01 youtu.be
The researchers became curious about how widespread this behavior might be and saw a research opportunity. After all, says John Martin, a researcher at Taronga Conservation Society, "Australian garbage bins have a uniform design across the country, and sulphur-crested cockatoos are common across the entire east coast."
Martin continues, "In 2018, we launched an online survey in various areas across Sydney and Australia with questions such as, 'What area are you from, have you seen this behavior before, and if so, when?'"
Word gets around
Credit: magspace/Adobe Stock
Although the cockatoos' maneuver was reported in only three suburbs before 2018, by the end of 2019, people in 44 areas reported observing the behavior. Clearly, more and more cockatoos were learning how to successfully dumpster dive.
As further proof, says Klump, "We observed that the birds do not open the garbage bins in the same way, but rather used different opening techniques in different suburbs, suggesting that the behavior is learned by observing others." One individual bird in north Sydney invented its own method, and the scientists saw it grow in popularity throughout the local population.
To track individual birds, the researchers marked 500 cockatoos with small red dots. Subsequent observations revealed that not all cockatoos are bin-openers. Only about 10 percent of them are, and they are mostly males. The other cockatoos apparently restrict their education to a different lesson: hang around with a bin-opener, and you will get supper.
Thanks to the surveys, the researchers consider the entire project to be a valuable citizen-science experiment. "By studying this behavior with the help of local residents, we are uncovering the unique and complex cultures of their neighborhood birds."
The few seconds of nuclear explosion opening shots in Godzilla alone required more than 6.5 times the entire budget of the monster movie they ended up in.