- New Prosthetic Hand Allows Man to Sense Temperature: ‘I could feel the warmth of another person’ Good News Network
- Prosthetic Arm Provides Sense of Heat and Cold IEEE Spectrum
- Prosthetic limb device enables users to ‘sense’ temperature difference The Guardian
- Towards a natural prosthetic hand: A study published in Med has developed a temperature-sensitive prosthetic limb that improves amputee interactions and feelings of human connection EurekAlert
- ‘You can get the feeling that you are touching another human’: New prosthetic device detects temperature Livescience.com
Tag Archives: temperature
Rome shatters temperature record as Switzerland, Spain and Greece battle fires – live – The Independent
- Rome shatters temperature record as Switzerland, Spain and Greece battle fires – live The Independent
- People and pets seek shade and cool as Spain sizzles under heat wave • FRANCE 24 English FRANCE 24 English
- Second heat wave in as many weeks grips Mediterranean while fires hit Spain, Switzerland and Greece ABC News
- Spanish capital bakes as Europe sees scorching temperatures | AFP AFP News Agency
- Urgent Spain holiday warning over ‘extreme risk’ alert for popular resort as 43C Charon ‘heat storm’ hits i… The US Sun
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Common Panic Response Can Desensitize Body to Temperature Changes
Summary: Panic-induced hyperventilation can reduce our ability to respond to environmental threats as it desensitizes body temperature to change.
Source: University of Tsukuba
The fight-or-flight response evolved to keep us safe from predators, but it can sometimes cause us to overreact in modern life when we don’t face the same dangers we once did.
Now, researchers from Japan have found that a common panic response may actually reduce our ability to deal with environmental threats.
In a study published this month in the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, researchers from the University of Tsukuba and Niigata University of Health and Welfare have revealed that a change in blood gas caused by intense breathing can desensitize the body to temperature changes.
When we encounter unexpected stressors in daily life, such as acute pain or fear, a common response is to begin breathing rapidly. This response, called hyperventilation, often involves breathing more quickly than the body really needs in order to deal with the perceived threat or danger.
“The purpose of hyperventilation during stress is not well understood, although it is thought to reduce sensitivity to the stressful stimulus,” says lead author of the study, Dr. Tomomi Fujimoto.
“However, whether and how hyperventilation reduces sensitivity to temperature changes is still unclear.”
To explore this, the researchers first tested sensitivity to temperature changes in young adults while breathing normally. Then, they were asked to breathe rapidly (hyperventilate), with or without the addition of carbon dioxide to their inspired air, to simulate hypocapnia, which is the normal decrease in carbon dioxide that occurs with hyperventilation, or normocapnia, which is a normal carbon dioxide level.
“The results were striking,” explains Professor Takeshi Nishiyasu, corresponding author. “Local detection of warm and cool stimuli was blunted when subjects hyperventilated with hypocapnia, but did not differ when they hyperventilated with normocapnia.”
In addition, less blood flow to the brain was observed during hyperventilation with hypocapnia than during hyperventilation with normocapnia. Although the reduced sensitivity to warm and cold stimuli was comparable on the forehead, the detection of warm stimuli was unchanged on the forearm.
“These findings suggest that hyperventilation-induced hypocapnia, not hyperventilation per se, attenuates local skin thermal perception, though changes in responses to warm stimuli may not be clearly perceived at some skin areas,” says Dr. Fujimoto.
Given that hyperventilation with hypnocapnia reduces blood flow to the part of the brain that receives signals about thermal stimulation, it is plausible that this is the reason for blunted thermal perception.
The findings from this study suggest that hypocapnia may be a mechanism by which hyperventilation reduces sensitivity to stress, while paradoxically dampening thermoregulatory behavior in severe hot and cold environments, which may contribute to heat stroke and accidental hypothermia.
About this neuroscience research news
Author: Press Office
Source: University of Tsukuba
Contact: Press Office – University of Tsukuba
Image: The image is in the public domain
Original Research: Open access.
“Hypocapnia attenuates local skin thermal perception to innocuous warm and cool stimuli in normothermic resting humans” by Tomomi Fujimoto et al. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology
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Abstract
Hypocapnia attenuates local skin thermal perception to innocuous warm and cool stimuli in normothermic resting humans
When one is exposed to a stressful situation in their daily life, a common response is hyperventilation. Although the physiological significance of stress-induced hyperventilation remains uncertain, this response may blunt perception of the stress-inducing stimulus.
This study examined the effects of voluntary hyperventilation and resultant hypocapnia on the local skin thermal detection threshold in normothermic resting humans.
Local skin thermal detection thresholds were measured in 15 young adults (three females) under three breathing conditions: 1) spontaneous breathing (Control trial), 2) voluntary hypocapnic hyperventilation (HH trial), and 3) voluntary normocapnic hyperventilation (NH trial). Local skin thermal detection thresholds were measured using thermostimulators containing a Peltier element that were attached to the forearm and forehead.
The temperature of the probe was initially equilibrated to the skin temperature, then gradually increased or decreased at a constant rate (±0.1 °C/s) until the participants felt warmth or coolness.
The difference between the initial skin temperature and the local skin temperature at which the participant noticed warmth/coolness was assessed as an index of the local skin warm/cool detection threshold. Local detection of warm and cool stimuli did not differ between the Control and NH trials, but it was blunted in the HH trial as compared with the Control and NH trials, except for detection of warm stimuli on the forearm.
These findings suggest that hyperventilation-induced hypocapnia, not hyperventilation per se, attenuates local skin thermal perception, though changes in responses to warm stimuli may not be clearly perceived at some skin areas (e.g., forearm).
‘Feels like summer’: Warm winter breaks temperature records in Europe
LONDON/BRUSSELS, Jan 4 (Reuters) – Record-high winter temperatures swept across parts of Europe over the new year, bringing calls from activists for faster action against climate change while offering short-term respite to governments struggling with high gas prices.
Hundreds of sites have seen temperature records smashed in the past days, from Switzerland to Poland to Hungary, which registered its warmest Christmas Eve in Budapest and saw temperatures climb to 18.9 degrees Celsius (66.02°F) on Jan. 1.
In France, where the night of Dec. 30-31 was the warmest since records began, temperatures climbed to nearly 25C in the southwest on New Year’s Day while normally bustling European ski resorts were deserted due to a lack of snow.
The Weather Service in Germany, where temperatures of over 20C were recorded, said such a mild turn of the year had not been observed in the country since records began in 1881.
Czech Television reported some trees were starting to flower in private gardens while Switzerland’s office of Meteorology and Climatology issued a pollen warning to allergy sufferers from early blooming hazel plants.
The temperature hit 25.1C at Bilbao airport in Spain’s Basque country. People basked in the sun as they sat outside Bilbao’s Guggenheim Museum or walked along the River Nervion.
“It always rains a lot here, it’s very cold, and it’s January, (but now) it feels like summer,” said Bilbao resident Eusebio Folgeira, 81.
French tourist Joana Host said: “It’s like nice weather for biking but we know it’s like the planet is burning. So we’re enjoying it but at the same time we’re scared.”
Scientists have not yet analysed the specific ways in which climate change affected the recent high temperatures, but January’s warm weather spell fits into the longer-term trend of rising temperatures due to human-caused climate change.
“Winters are becoming warmer in Europe as a result of global temperatures increasing,” said Freja Vamborg, climate scientist at the European Union’s Copernicus Climate Change Service.
It follows another year of extreme weather events that scientists concluded were directly linked to global warming, including deadly heatwaves in Europe and India, and flooding in Pakistan.
“The record-breaking heat across Europe over the new year was made more likely to happen by human-caused climate change, just as climate change is now making every heatwave more likely and hotter,” said Dr Friederike Otto, climate scientist at Imperial College London.
Temperature spikes can also cause plants to start growing earlier in the year or coax animals out of hibernation early, making them vulnerable to being killed off by later cold snaps.
Robert Vautard, director of France’s Pierre-Simon Laplace Institute, said that while temperatures peaked from Dec. 30 to Jan. 2, the mild spell has lasted for two weeks and is still not over. “This is actually a relatively long-lived event,” he said.
EMPTY SLOPES
French national weather agency Meteo France attributed the anomalous temperatures to a mass of warm air moving to Europe from subtropical zones.
It struck during the busy skiing season, leading to cancelled trips and empty slopes. Resorts in the northern Spanish regions of Asturias, Leon and Cantabria have been closed since the Christmas holidays for lack of snow.
On Jahorina mountain above the Bosnian capital Sarajevo, which hosted the 1984 Winter Olympics, it should have been one of the busiest weeks of the season. Instead, the chair-lifts hung lifeless above the grassy slopes. In one guesthouse a couple ate dinner alone in the restaurant, the only guests.
A ski jumping event in Zakopane, southern Poland, planned for the weekend of Jan. 7-8 was cancelled.
Karsten Smid, a climate expert at Greenpeace Germany, said while some climate change impacts were already unavoidable, urgent action should be taken to prevent even more drastic global warming.
“What’s happening right now is exactly what climate scientists warned us about 10, 20 years ago, and that can no longer be prevented now,” Smid said.
WEATHER EASES GAS STRAIN
The unusually mild temperatures have offered some short-term relief to European governments who have struggled to secure scarce gas supplies and keep a lid on soaring prices after Russia slashed deliveries of the fuel to Europe.
European governments have said this energy crisis should hasten their shift from fossil fuels to clean energy – but in the short term, plummeting Russian fuel supplies have left them racing to secure extra gas from elsewhere.
Gas demand has fallen for heating in many countries due to the mild spell, helping to reduce prices.
The benchmark front-month gas price was trading at 70.25 euros per megawatt hour on Wednesday morning, its lowest level since February 2022 – just before Russia’s invasion of Ukraine.
The head of Italy’s energy authority predicted that regulated energy bills in the country would fall this month, if the milder temperatures help keep gas prices lower.
However, a note by Eurointelligence cautioned that this should not lull governments into complacency about Europe’s energy crisis.
“While it will give governments more fiscal breathing room in the first part of this year, resolving Europe’s energy problems will taken concerted action over the course of several years,” it said. “Nobody should believe this is over yet.”
Reporting by Kate Abnett, Richard Lough, Alan Charlish, Krisztina Than, Luiza Ilie, Susanna Twidale, Riham Alkousaa, Jason Hovet, Emma Pinedo, Kirsten Donovan, Federico Maccioni; writing by Matthias Williams; Editing by Janet Lawrence and Mark Heinrich
Our Standards: The Thomson Reuters Trust Principles.
Something Strange Happens to The Temperature Around Freshly Formed Bubbles : ScienceAlert
When you stop and think about bubbles, you realize that they’re everywhere: in the dishwasher, on the top of your beer, on the crests of waves, in the saliva between your teeth, and, of course, in bubble gun toys.
That means the physics of bubbles are important in all kinds of scenarios. With that in mind, researchers from the Université Paris-Saclay in France have made an intriguing discovery about the film surrounding bubbles.
This film can, in some cases, be up to 8°C (14.4°F) cooler than the environment around it, the researchers say. The findings build on previous investigations into how changes in temperature can trigger the thinning and evaporation of a liquid film.
“Although this effect is often considered in studies devoted to drop evaporation, to the best of our knowledge, the significance of cooling-induced evaporation is not mentioned in the literature on soap films and foams,” write the researchers in their published paper.
To get a closer look at these soap films and foams – bubbles, essentially – the team put together a mixture made of washing up liquid, water, and glycerol, with variations in the final substance used to fine-tune the lifetime and evaporation rate of the bubbles.
These bubbles were tested in different temperature and humidity conditions. In some cases, the difference between the soap film and the ambient air was significant – maxing out at that 8°C level.
While it was already known that soap films lose liquid via evaporation in an attempt to release energy (just like we do when we sweat to cool down), it’s been assumed that the temperature of these films matched the surrounding environment.
“Experimentally, we observed that the temperature first decreases and then increases until the ambient temperature is reached again,” write the researchers.
“We reported that the magnitude of the cooling effect depends on both the relative humidity and the initial glycerol concentration, decreasing the values of these two parameters leading to stronger effects.”
One of the ways that this research could be useful is in industrial processes where managing the stability of bubbles is vital. Temperature variations between bubble films and the outside world will affect those calculations.
The researchers say that the viscosity and the surface tension of soap films are two of the properties that are likely to be influenced by the temperature gap that they’ve found; indeed, soapy objects may not have a uniform thermal field all the way around.
This is the first study of its kind, though, and plenty more research is required before scientists can say just how the temperature of the film that makes up a bubble can be impacted.
“We propose a model describing the temperature drop of soap films after their formation that is in quantitative agreement with our experiments,” write the researchers.
“We emphasize that this cooling effect is significant and must be carefully considered in future studies on the dynamics of soap films.”
The research has been published in Physical Review Letters.
AMD Radeon RX 7900 XTX Temperature Issues Continue To Rise & PowerColor Steps In To Help Consumers
Recently, a Reddit user posted that his reference AMD Radeon RX 7900 XTX graphics card was reaching 110C Junction temps while playing the new Modern Warfare II. However, when contacting AMD with an RMA request, he was denied, with the company stating that “The temperatures are normal. If there is any issue, please, contact us back.” Another user made a successful request but was denied a refund for the previously opened box. The company has since received a bit of backlash for the issue, especially with the growing number of cases arising.
More cases of high temperatures on AMD Radeon RX 7900 XTX graphics cards continue to rise, with companies like PowerColor stepping up to help consumers
Before this new AMD development, NVIDIA received backlash for overheating and melting 12VHPWR connectors on the flagship NVIDIA GeForce RTX 4090 GPU, which surpassed thirty individuals and reported cases of issues after the graphics card launched.
What is unique about the AMD situation is that it is currently affecting the reference and AMD-manufactured Radeon RX 7900 series GPUs. It covers any cards sold by AMD partners or the company but not custom-created GPUs utilizing the same graphics architecture. It is speculated that a flaw could be in a few coolers or mounting designs as indicated by De8auer in the video below:
Three years ago, AMD posted in the company’s blog an article titled, “AMD Radeon Community Update: More Control Over GPU Power and Performance, Enhanced Thermal Monitoring, Maximized Performance.” When discussing junction temperatures in the enhanced thermal monitoring of the AMD Radeon VII GPU, they posted this statement:
… Instead of setting a conservative, ‘worst case’ throttling temperature for the entire die, the RadeonTM RX 5700 series GPUs will continue to opportunistically and aggressively ramp clocks until any one of the many available sensors hits the ‘hotspot’ or ‘Junction’ temperature of 110 degrees Celsius. Operating at up to 110C Junction Temperature during typical gaming usage is expected and within spec. This enables the RadeonTM RX 5700 series GPUs to offer much higher performance and clocks out of the box, while maintaining acoustic and reliability targets.
One of the technical engineering leads on the AMD Radeon RX 7900 XTX, “Kevin,” does state that as of yesterday, the company is aware of the hotspot issue and is actively investigating and putting together a plan of action “to repro and collect serial numbers.” He further explains that the current COVID situation overseas is slowing the process but agrees that a mechanical issue would fall under creating and fulfilling an RMA for consumers. Still, they are also looking into firmware updates to fix isolated incidents where a software fix would be necessary instead of a hardware replacement. “Kevin” also discusses edge heating, the temperature near the edge of the silicon on a GPU, stating that 90° edge temperatures are abnormal, but 70° edge temperatures are nominal.
Reddit user and PowerColor representative on the platform, “PowerColorSteven,” is doing his part to assist consumers with this current issue about the AMD Radeon RX 7900 XTX graphics cards. For those who may not remember Steven, we mentioned in this article that the company had a prior issue where the AMD RX 6700 XT series GPUs were shipping with the thermal pad covers still attached, which, at the time, would cause high temperatures from the graphics card. The sales representative has been closely monitoring this issue for the last couple of days and recently posted this as a pinned thread on Reddit:
uh… just adding this in here in case anybody has not seen my other posts.
if you are dealing with the 110c issue and nobody else is helping you out. doenst matter which (AIB you bought this from) you bought it from. send me an email or direct message (since my emails are not working right today) (also, please dont use chat, that shit dont work right). i am putting together a list for my AMD contacts of how many issues we are seeing. they asked if it was just a few users. i said its def more than a handful, so now i need to show some sort of backing for my fat mouth. send me serial numbers. i am sending an email to the AMD guys with how many units are affect. powercolor. sapphire. gigabyte. amd direct. whatever. send me serial numbers. hopefully amd will get some news for all of us, but regardless, when i hear something of substance, i’ll make a post to provide some level of guidance on how to go about getting this sorted out.
— User “PowerColorSteven,” aka “sales guy or something” on Reddit
However, it is hard to find out which companies accept RMAs and fulfill them, as the number of recorded cases have stated that some are allowed while others are denied, even when it is the same manufacturer. Several other theories are also arising about the problem, from uneven cold plates to using a graphite thermal pad to fix the issue. With the number of cases rising during the initial reports, it is not recommended to alleviate the problem but to hold on until an official statement or acceptance of a series-wide RMA is allowed by AMD.
News Sources: Tom’s Hardware, Reddit (AMD), AMD blog, Reddit (PowerColor)
Christmas weather: The winter storm blasting the US is snarling holiday travel and bringing record-breaking temperature drops
CNN
—
A major arctic blast is plunging temperatures to dangerous levels in much of the country and a developing “bomb cyclone” is set to unload heavy snow and blizzard conditions especially in the Midwest on Thursday and Friday – a combination making for a perilous few days leading up to Christmas.
The cold air and storm are affecting nearly every state in some way: More than 110 million people coast-to-coast were under winter-weather alerts for snow or icy conditions Thursday morning, the National Weather Service said.
And more than 90 million people were under wind-chill alerts from the Canadian border to the Mexican border and from Washington state to Florida, with below-zero wind chills recorded as far south as Texas on Thursday morning and expected to reach the Southeast by Friday.
“Life-threatening wind chills over the Great Plains (will) overspread the eastern half of the nation by Friday,” the Weather Prediction Center said – and wind chills below minus 50 degrees already were reported in the past day in parts of Montana, South Dakota and Wyoming.
FOLLOW LIVE UPDATES
Temperatures in some cases plunged with record-breaking speed: Denver saw a 65-degree drop in 16 hours from Wednesday (50 degrees) to Thursday at 5 a.m. (minus 15 degrees). A 37-degree plunge over one hour at Denver International Airport is preliminarily the biggest one-hour drop recorded there, according to the National Weather Service in Boulder.
Snow, meanwhile, has been hitting parts of the West and is expected in the next two days across much of the country’s eastern half.
A major snowstorm is shaping up for the Midwest and Great Lakes especially: Widespread light to moderate snowfall, but with powerful winds that may make for impossible travel conditions.
“Heavy snowfall rates of 1-2”/hour, along with wind gusts of over 50 mph will result in near-zero visibility and considerable blowing and drifting of snow,” the prediction center said.
The storm is expected to become a “bomb cyclone” Thursday evening into Friday, reaching the pressure equivalent of a Category 2 hurricane as it moves into the Great Lakes.
More than 1,700 flights have been canceled across the US on Thursday, according to the flight tracking site FlightAware, snarling air travel amid the busy holiday season.
Nearly zero visibility on the roads led to many highway closures between Colorado and Wyoming on Wednesday. The Wyoming Highway Patrol said it responded to nearly 800 calls for service in a 12-hour period Wednesday, telling motorists to stay off the roads.
In South Dakota, more than 100 vehicles were stranded on snow-covered roadways under low visibility conditions Wednesday night, the Pennington County Sheriff’s Office said.
Even Florida won’t be spared, with residents of the Sunshine State expected to see sudden temperature drops Friday. Some cities in the South – including Nashville and Memphis – are expected to see snow Thursday.
Flooding, meanwhile, is possible in parts of the Northeast, including Washington and Philadelphia, as rain hits the area Thursday before temperatures plummet overnight and bring a “flash freeze.”
President Joe Biden received a briefing on the weather Thursday morning at the White House, from the National Weather Service and Federal Emergency Management Agency. He encouraged Americans to heed the warnings of local officials and to stay safe in the face of the extreme cold.
“This is really a very serious weather alert here,” Biden said, adding that the White House has reached out to 26 governors in the affected regions.
• Snow already was falling Thursday morning from Colorado to Michigan
• Snow and high winds are expected to make for terrible travel conditions from eastern Montana and the northern Plains into the Midwest and upstate New York.
• Blizzard warnings – meaning snow and wind of 35 mph will frequently reduce visibility to less than a quarter of a mile for at least three hours – were in effect Thursday morning in some of those areas, including just southwest of Minneapolis; just south and east of Chicago, and western and northern Michigan.
• Snow is expected to hit Chicago around noon.
• Major cities including Minneapolis, Chicago, Kansas City, St. Louis, Indianapolis, Cleveland and Detroit are under winter storm warnings.
• Wind chill warnings, watches and advisories were in effect for more than 30 states from Washington to Florida on Thursday.
• The arctic front will push south into the Gulf of Mexico and sweep off the Eastern Seaboard by late Friday, bringing cold into the Deep South.
• Thursday’s daytime temperatures may stay below zero in the northern Plains and get barely above that in the central Plains.
• Areas further south – Texas and the Gulf Coast – will see temperatures in the single digits and teens Thursday evening, the Storm Prediction Center said.
• Officials in several southern states are warning residents to take precautions. Alabama warned Thursday and Friday would likely feature “the coldest December airmass to hit the state since 1989,” the state’s emergency management agency said. Friday’s lows in that state were expected to range from the single digits in the north to the low 20s by the Gulf of Mexico.
• Louisiana Gov. John Bel Edwards asked residents Thursday to check on friends and family members that might have a hard time with the frigid temperatures. Lows Friday and Saturday were expected to be in the teens and 20s there.
Temperature rising on Soyuz, crew not in danger
The temperature on the Soyuz capsule docked at the International Space Station has risen but the crew are not in danger, the Russian space agency said Friday as it assesses a leak.
Roscosmos said a number of tests had been conducted following the discovery of a coolant leak on the Soyuz MS-22, and the temperature in the capsule had increased to 30 degrees Celsius (86 degrees Fahrenheit).
On Wednesday, the leak forced the last-minute postponement of a spacewalk by cosmonauts Sergei Prokopiev and Dmitry Petelin.
The spacecraft is currently under evaluation to ensure it can ferry the two Russian cosmonauts and their American colleague Frank Rubio back to Earth.
In a statement, Roscosmos said the “slight change in temperature,” was “not critical for the operation of the equipment and the comfort of the crew.”
Sergei Krikalev, a former cosmonaut who heads the crewed space flight programme for Roscosmos, said the leak may have been caused by a tiny meteorite striking Soyuz.
Dramatic NASA TV images showed white particles resembling snowflakes streaming out of the rear of the vessel for hours.
According to NASA, “the majority of fluid had leaked out” by Thursday, but the coolant did not pose any danger to the crew members, who were not exposed after the spacewalk was called off.
“Temperatures and humidity within the Soyuz spacecraft (…) are within acceptable limits,” the American engineers also said.
Flight controllers, meanwhile, conducted a “successful test” of the spacecraft thrusters on Friday, NASA said, adding that other evaluations remain in progress.
The spacewalk is now expected to take place on December 21.
Space has been a rare avenue of cooperation between Moscow and Washington since the start of Russia’s intervention in Ukraine in February and ensuing Western sanctions that shredded ties between the two countries.
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The Physics of Scuba Diving
Another unit is the bar, where 1 bar is equal to 14.5 psi. The value of 1 bar is very close to the pressure of air on Earth. The atmospheric pressure of the air that surrounds you right now is probably 14.5 psi. (Yes, I said “probably” because I don’t want to judge you. Maybe you are reading this from the top of Mount Everest, where the pressure is just 4.9 psi, because there is less air above you pushing down. If so, send me a picture.) In terms of force and area, it is equal to 100,000 newtons per square meter.
Water is also made of tiny moving molecules that act like balls, and those molecules collide with underwater objects (like people), producing pressure. Water has many more molecules than the same volume of air, which means there are more collisions to produce a greater pressure. But just like going to the top of Mount Everest decreases the air pressure, going deeper in water increases the pressure, because gravity pulls downward on the molecules of water. For every 10 meters of depth, the pressure increases by 1 bar, or 14.5 psi. That means that on a dive 20 meters (around 60 feet) below sea level, there would be a water pressure of 43.5 psi, three times greater than the air pressure at Earth’s surface.
(The fact that pressure increases with depth prevents all the ocean’s water from collapsing into an infinitely thin layer. Since the pressure is greater the deeper you go, the water underneath pushes up more than the water above it pushes down. This difference compensates for the downward gravitational force, so the water level stays constant.)
It might sound like 43.5 psi is too much for a person to handle, but it’s actually not that bad. Human bodies are very adaptable to changes in pressure. If you have been to the bottom of a swimming pool, you already know the answer to this pressure problem—your ears. If the water pressure on the outside of your eardrum is greater than the pressure from the air inside your inner ear, the membrane will stretch, and it can really hurt. But there is a nice trick to fix this: If you push air into your middle ear cavity by pinching your nose closed while attempting to blow air out of it, air will be forced into this cavity. With more air in the inner ear, the pressure on both sides of the membrane will be equal and you will feel normal. This is called “equalization,” for hopefully obvious reasons.
There’s actually another air space that you need to equalize while diving—the inside of your scuba mask. Don’t forget to add air to it as you go deeper, or that thing will awkwardly squish your face.
There is one other physics mistake a diver could make. It’s possible to create an enclosed air space in your lungs by holding your breath. Suppose you hold your breath at a depth of 20 meters and then move up to a depth of 10 meters. The pressure inside your lungs will stay the same during this ascent, because you have the same lung volume, and they contain the same amount of air. However, the water pressure outside of them will decrease. The reduced external pressure on your lungs makes it as though they are overinflated. This can cause tears in lung tissue, or even force air into the bloodstream, which is officially bad stuff.
Buoyancy
There’s another problem to deal with when you are underwater: floating and sinking. If you want to stay underwater, it’s useful to sink instead of float—to a point. I don’t think anyone wants to sink to such depths that they never return. Also, it’s nice to be able to float when you’re at the surface. Luckily, scuba divers can change their “floatiness” for different situations. This is called buoyancy control.
Things sink when the downward-pulling gravitational force is greater than the upward-pushing buoyancy force. If these two forces are equal, then the object will be neutrally buoyant and neither rise nor sink. It’s like hovering, but in water, and it is essentially what you want to do when scuba diving.
“Stabilizing Feedback” Confirmed by MIT Scientists – Earth Can Regulate Its Own Temperature Over Millennia
MIT scientists confirm that Earth harbors a “stabilizing feedback” mechanism that acts over hundreds of thousands of years to pull the climate back from the brink, keeping global temperatures within a steady, habitable range.
Earth can regulate its own temperature over millennia, new research finds.
Scientists have confirmed that a “stabilizing feedback” on 100,000-year timescales keeps global temperatures in check.
From global volcanism to planet-cooling ice ages and dramatic shifts in solar radiation, the Earth’s climate has undergone some big changes. And yet for the last 3.7 billion years, life has kept on beating.
Now, new research by
“On the one hand, it’s good because we know that today’s global warming will eventually be canceled out through this stabilizing feedback. But on the other hand, it will take hundreds of thousands of years to happen, so not fast enough to solve our present-day issues.” — Constantin Arnscheidt
Just how does Earth accomplish this? A likely mechanism is “silicate weathering” — a geological process by which the slow and steady weathering of silicate rocks involves chemical reactions that ultimately draw carbon dioxide out of the atmosphere and into ocean sediments, trapping the gas in rocks.
It has been long suspected by researchers that silicate weathering plays a major role in regulating the Earth’s carbon cycle. The mechanism of silicate weathering could provide a geologically constant force in keeping carbon dioxide — and global temperatures — in check. But until now, there’s never been direct evidence for the continual operation of such a feedback.
The new findings are based on a study of paleoclimate data that record changes in average global temperatures over the last 66 million years. The MIT team applied a mathematical analysis to see whether the data revealed any patterns characteristic of stabilizing phenomena that reined in global temperatures on a geologic timescale.
They found that indeed there appears to be a consistent pattern in which the Earth’s temperature swings are dampened over timescales of hundreds of thousands of years. The duration of this effect is similar to the timescales over which silicate weathering is predicted to act.
A study by MIT researchers confirms that the planet harbors a “stabilizing feedback” mechanism that acts over hundreds of thousands of years to pull the climate back from the brink, keeping global temperatures within a steady, habitable range. Credit: Christine Daniloff, MIT; NASA
The results are the first to use actual data to confirm the existence of a stabilizing feedback, the mechanism of which is likely silicate weathering.How the Earth has remained habitable through dramatic climate events in the geologic past can be explained by this stabilizing feedback.
“On the one hand, it’s good because we know that today’s global warming will eventually be canceled out through this stabilizing feedback,” says Constantin Arnscheidt, a graduate student in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS). “But on the other hand, it will take hundreds of thousands of years to happen, so not fast enough to solve our present-day issues.”
The study is co-authored by Arnscheidt and Daniel Rothman, professor of geophysics at MIT.
Stability in data
Scientists have previously seen hints of a climate-stabilizing effect in the Earth’s carbon cycle: Chemical analyses of ancient rocks have shown that the flux of carbon in and out of Earth’s surface environment has remained relatively balanced, even through dramatic swings in global temperature. Furthermore, models of silicate weathering predict that the process should have some stabilizing effect on the global climate. And finally, the fact of the Earth’s enduring habitability points to some inherent, geologic check on extreme temperature swings.
“You have a planet whose climate was subjected to so many dramatic external changes. Why did life survive all this time? One argument is that we need some sort of stabilizing mechanism to keep temperatures suitable for life,” Arnscheidt says. “But it’s never been demonstrated from data that such a mechanism has consistently controlled Earth’s climate.”
Arnscheidt and Rothman sought to confirm whether a stabilizing feedback has indeed been at work, by looking at data of global temperature fluctuations through geologic history. They worked with a range of global temperature records compiled by other scientists, from the chemical composition of ancient marine fossils and shells, as well as preserved Antarctic ice cores.
“This whole study is only possible because there have been great advances in improving the resolution of these deep-sea temperature records,” Arnscheidt notes. “Now we have data going back 66 million years, with data points at most thousands of years apart.”
Speeding to a stop
To the data, the team applied the mathematical theory of stochastic differential equations, which is commonly used to reveal patterns in widely fluctuating datasets.
“We realized this theory makes predictions for what you would expect Earth’s temperature history to look like if there had been feedbacks acting on certain timescales,” Arnscheidt explains.
Using this approach, the team analyzed the history of average global temperatures over the last 66 million years, considering the entire period over different timescales, such as tens of thousands of years versus hundreds of thousands, to see whether any patterns of stabilizing feedback emerged within each timescale.
“To some extent, it’s like your car is speeding down the street, and when you put on the brakes, you slide for a long time before you stop,” Rothman says. “There’s a timescale over which frictional resistance, or a stabilizing feedback, kicks in, when the system returns to a steady state.”
Without stabilizing feedbacks, fluctuations of global temperature should grow with timescale. But the team’s analysis revealed a regime in which fluctuations did not grow, implying that a stabilizing mechanism reigned in the climate before fluctuations grew too extreme. The timescale for this stabilizing effect — hundreds of thousands of years — coincides with what scientists predict for silicate weathering.
Interestingly, Arnscheidt and Rothman found that on longer timescales, the data did not reveal any stabilizing feedbacks. That is, there doesn’t appear to be any recurring pull-back of global temperatures on timescales longer than a million years. Over these longer timescales, then, what has kept global temperatures in check?
“There’s an idea that chance may have played a major role in determining why, after more than 3 billion years, life still exists,” Rothman offers.
In other words, as the Earth’s temperatures fluctuate over longer stretches, these fluctuations may just happen to be small enough in the geologic sense, to be within a range that a stabilizing feedback, such as silicate weathering, could periodically keep the climate in check, and more to the point, within a habitable zone.
“There are two camps: Some say random chance is a good enough explanation, and others say there must be a stabilizing feedback,” Arnscheidt says. “We’re able to show, directly from data, that the answer is probably somewhere in between. In other words, there was some stabilization, but pure luck likely also played a role in keeping Earth continuously habitable.”
Reference: “Presence or absence of stabilizing Earth system feedbacks on different time scales” by Constantin W. Arnscheidt and Daniel H. Rothman, 16 November 2022, Science Advances.
DOI: 10.1126/sciadv.adc9241
This research was supported, in part, by a MathWorks fellowship and the National Science Foundation.