Tag Archives: temperature

Science

The Speed of Sound on Mars Is Strangely Different, Scientists Reveal

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Scientists have confirmed the speed of sound on Mars, using equipment on the Perseverance rover to study the red planet’s atmosphere, which is very different to Earth’s.  

What they discovered could have some strange consequences for communication between future Martians.

 

The findings suggest that trying to talk in Mars’ atmosphere might produce a weird effect, since higher-pitched sound seems to travel faster than bass notes. Not that we’d try, since Mars’ atmosphere is unbreathable, but it’s certainly fun to think about!

From a science perspective, the findings, announced at the 53rd Lunar and Planetary Science Conference by planetary scientist Baptiste Chide of the Los Alamos National Laboratory, reveal high temperature fluctuations at the surface of Mars that warrant further investigation.

The speed of sound is not a universal constant. It can change, depending on the density and temperature of the medium through which it travels; the denser the medium, the faster it goes.

That’s why sound travels about 343 meters (1,125 feet) per second in our atmosphere at 20 degrees Celsius, but also at 1,480 meters per second in water, and at 5,100 meters per second in steel.

Mars’ atmosphere is a lot more tenuous than Earth’s, around 0.020 kg/m3, compared to about 1.2 kg/m3 for Earth. That alone means that sound would propagate differently on the red planet.

But the layer of the atmosphere just above the surface, known as the Planetary Boundary Layer, has added complications: During the day, the warming of the surface generates convective updrafts that create strong turbulence.

 

Conventional instruments for testing surface thermal gradients are highly accurate, but can suffer from various interference effects. Fortunately, Perseverance has something unique: microphones that can allow us to hear the sounds of Mars, and a laser that can trigger a perfectly timed noise.

The SuperCam microphone was included to record acoustic pressure fluctuations from the rover’s laser-induced breakdown spectroscopy instrument as it ablates rock and soil samples at the Martian surface.

NASA’s Perseverance rover on Mars. (NASA/JPL-Caltech/MSSS)

This came with an excellent benefit, as it turns out. Chide and his team measured the time between the laser firing and the sound reaching the SuperCam microphone at 2.1 meters altitude, to measure the speed of sound at the surface.

“The speed of sound retrieved by this technique is computed over the entire acoustic propagation path, which goes from the ground to the height of the microphone,” the researchers write in their conference paper.

“Therefore, at any given wavelength it is convoluted by the variations of temperature and wind speed and direction along this path.”

The results back up predictions made using what we know of the Martian atmosphere, confirming that sounds propagate through the atmosphere near the surface at roughly 240 meters per second.

 

However, the quirk of Mars’ shifting soundscape is something completely out of the blue, with conditions on Mars leading to a quirk not seen anywhere else.

“Due to the unique properties of the carbon dioxide molecules at low pressure, Mars is the only terrestrial-planet atmosphere in the Solar System experiencing a change in speed of sound right in the middle of the audible bandwidth (20 Hertz to 20,000 Hertz),” the researchers write.

At frequencies above 240 Hertz, the collision-activated vibrational modes of carbon dioxide molecules do not have enough time to relax, or return to their original state. The result of this is that sound travels more than 10 meters per second faster at higher frequencies than it does at low ones.

This could lead to what the researchers call a “unique listening experience” on Mars, with higher-pitched sounds arriving sooner to the listener than lower ones.

Given that any human astronauts traveling to Mars anytime soon will need to be wearing pressurized spacesuits with comms equipment, or living in pressurized habitat modules, this is unlikely to pose an immediate problem – but it could be a fun concept for science-fiction writers to tinker with.

 

Because the speed of sound changes due to temperature fluctuations, the team was also able to use the microphone to measure large and rapid temperature changes on the Martian surface that other sensors had not been able to detect. This data can help fill in some of the blanks on Mars’ rapidly changing planetary boundary layer.

The team plans to continue using SuperCam microphone data to observe how things like daily and seasonal variations might affect the speed of sound on Mars. They also plan to compare acoustic temperature readings to readings from other instruments to try to figure out the large fluctuations.

You can read the conference paper on the conference website.

 

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Technology

Honor’s Earbuds 3 Pro come with built-in temperature monitoring

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Along with its 100W charging-capable Magic 4 phone, Honor has announced new Earbuds 3 Pro that include built-in temperature monitoring technology. According to Honor, this technology is an industry first, that owners can experience once the €199 buds are released.

Temperature monitoring, among other signals, has become especially important to tracking someone’s health during the pandemic, and checking your temperature at home using infrared ear thermometers is already widely available. Wearables incorporating temperature monitoring sounds like something that isn’t far off, and the idea even reportedly caught Apple’s eye while developing updates to its AirPods.

Image: Honor

Wearers can tap the buds three times to activate temperature monitoring, with continuous measurement and even an “abnormal temperature alert.” However, a footnote mentions that there are “not for any medical purpose,” and that for now, the device is for demonstration purposes only until it has been brought into compliance with related regulations.

The Wall Street Journal reported in October that Apple was looking into adding the feature in its AirPods, making the product a part of its growing platform of health tech. An earlier rumor mentioned temperature monitoring as a feature for the Apple Watch Series 7, but it wasn’t there when the device launched in September.

Though these Earbuds 3 Pro aren’t likely to be sold in the US, the product could be an indicator that the approach is realistic. UK startup Bodytrak showed off its own temperature-monitoring earbuds a few years ago, but they don’t appear to be production-ready yet.

Honor didn’t provide many details while announcing the earbuds at MWC 2022 but confirmed a few other features outside of the temperature monitoring. The Earbuds 3 Pro’s basic features include adaptive active noise cancellation (ANC) that will adjust for the wearer depending on their listening environment. The earbuds will have 11mm dynamic driver with enhanced sound details and bass and claim to have up to 24 hours of battery life before their charging case is fully discharged, as well as fast charging that can provide two hours of music playback with just five minutes of charging.

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Science

New Breakthrough Could Bring Time Crystals Out of The Lab And Into The Real World

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We’ve just taken another step closer to time crystals that can be used for practical applications.

New experimental work has yielded a room-temperature time crystal in a system that is not isolated from its ambient surroundings.

 

This, the researchers say, paves the way for chip-scale time crystals that can be used in real-world settings, away from expensive laboratory equipment required to keep them running.

“When your experimental system has energy exchange with its surroundings, dissipation and noise work hand-in-hand to destroy the temporal order,” says engineer Hossein Taheri of the University of California, Riverside.

“In our photonic platform, the system strikes a balance between gain and loss to create and preserve time crystals.”

Time crystals, sometimes also referred to as space-time crystals, and only confirmed to actually exist a few years ago, are as fascinating as the name suggests. They are a phase of matter that is a lot like regular crystals, with one very significant additional property.

In regular crystals, the constituent atoms are arranged in a fixed, three-dimensional grid structure – the atomic lattice of a diamond or quartz crystal is a good example. These repeating lattices can differ in configuration, but within a given formation they don’t move around very much; they only repeat spatially.

In time crystals, the atoms behave a bit differently. They oscillate, spinning first in one direction, and then the other. These oscillations – referred to as ‘ticking’ – are locked to a regular and particular frequency. Where the structure of regular crystals repeats in space, in time crystals it repeats in space and time.

 

To study time crystals, scientists often use Bose-Einstein condensates of magnon quasiparticles. These have to be kept at extraordinarily low temperatures, very close to absolute zero. This requires very specialized, sophisticated laboratory equipment.

In their new research, Taheri and his team created a time crystal without supercooling. Their time crystals were all-optical quantum systems created at room temperature. First, they took a tiny microresonator, a disk made out of magnesium fluoride glass just one millimeter in diameter. Then, they bombarded this optical microresonator with the beams of two lasers.

The self-preserving subharmonic spikes (solitons) that resulted from the frequencies generated by the two laser beams indicated the creation of time crystals. The system creates a rotating lattice trap for optical solitons that then display periodicity.

To maintain the integrity of the system at room temperature, the team used self-injection locking, a technique that ensures the laser’s output maintains a certain optical frequency. This means that the system could be moved out of the lab and used for field applications, the researchers say.

In addition to potential future explorations of the properties of time crystals, such as phase transitions, and time crystal interactions, the system could be used to take new measurements of time itself. Time crystals might even be integrated, one day, into quantum computers.

“We hope that this photonic system can be utilized in compact and lightweight radiofrequency sources with superior stability as well as in precision timekeeping,” Taheri says.

The team’s research has been published in Nature Communications.

 

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Science

Physicists Have Observed a Strange New Kind of Transition in Electronic Crystals

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As basic science teaches us, changes in temperature can result in phase transitions in materials – like when water solidifies as ice in the freezing cold.

However, in some cases the temperature that triggers the change is different depending on whether the material is cooling down or warming up. This is known as a hysteresis loop, and researchers think they’ve discovered a weird and entirely new example of this phenomenon.

 

It’s not a transition you’re likely to see in everyday life, requiring a layered compound crystalline solid called EuTe4, huge temperature ranges, and a kilometer-long track for firing fast-moving charged particles deployed to create brilliant laser light.

Through such a lab setup, scientists spotted that the hysteresis loop for EuTe4 covered a giant temperature range of at least 400 Kelvins – far more than the usual range for a crystalline solid like this, which would usually only be in the tens of Kelvins at most.

“This finding immediately caught our attention, and our combined experimental and theoretical characterization of EuTe4 challenges conventional wisdom on the type of hysteretic transitions that can occur in crystals,” says physicist Baiqing Lyu from the Massachusetts Institute of Technology (MIT).

The research got curiouser and curiouser from there. There was no change in the electronic or lattice structure in the material across the temperature range that was measured, which again isn’t how phase transitions in crystals should work.

While it’s early days for this discovery, the team does have a few ideas about what might be happening: the particular way electrons are arranged in EuTe4 causes a secondary electronic crystal to form, and it could be that as this second layer moves and shifts, it creates different configurations in the hysteresis loop.

 

Further experiments showed that the researchers were able to significantly vary the electrical resistance of the material by cooling down or warming up the crystals – another indication of something strange and unexpected going on.

“This observation indicates to us that the electrical property of the material somehow has a memory of its thermal history, and microscopically the properties of the material can retain the traits from a different temperature in the past,” says physicist Alfred Zong from MIT.

“Such ‘thermal memory’ may be used as a permanent temperature recorder.”

This opens up a whole host of possibilities. One of the ways this could be used by scientists is to measure the electrical resistance of EuTe4 at room temperature, and from there deduce the coldest or hottest temperature the material has previously experienced, because of this ‘thermal memory’.

According to the team, the work done here could be expanded further to look at other solids and how they change when exposed to extreme temperature ranges. It could be particularly promising in terms of getting more control over materials used in switches and memory in computers.

First though, further research is needed. The researchers suspect that there’s more to discover beyond the 400 Kelvin range – that was simply as far as their setup would allow them to go. After more analysis, hysteresis might also be controlled by other ways besides changing the temperature.

“The next goal is to trick EuTe4 into a different resistive state after shining a single flash of light, making it an ultrafast electrical switch that can be used, for instance, in computing devices,” says physicist Nuh Gedik from MIT.

The research has been published in Physical Review Letters.

 

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Science

Earth’s Insides Are Cooling Faster Than We Thought, And It Will Mess Things Up

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Earth formed 4.5 billion years or so ago. Ever since then, it’s been slowly cooling on the inside.

While the surface and atmosphere temperatures fluctuate over the eons (and yes, those external temperatures are currently warming), the molten interior – the beating heart of our planet – has been cooling this entire time.

 

That’s not a glib metaphor. The rotating, convecting dynamo deep inside Earth is what generates its vast magnetic field, an invisible structure that scientists believe protects our world and allows life to thrive. In addition, mantle convection, tectonic activity and volcanism are thought to help sustain life through the stabilization of global temperatures and the carbon cycle.

Because Earth’s interior is still cooling, and will continue to do so, this means that eventually the interior will solidify, and the geological activity will cease, possibly turning Earth into a barren rock, akin to Mars or Mercury. New research has revealed that may happen sooner than previously thought.

The key could be a mineral at the boundary between Earth’s outer iron-nickel core and the molten fluid lower mantle above it. This boundary mineral is called bridgmanite, and how quickly it conducts heat will influence how quickly heat seeps through the core and out into the mantle.

Determining that rate is not as simple as testing the conductivity of bridgmanite in ambient atmospheric conditions. Thermal conductivity can vary based on pressure and temperature, which are vastly different deep inside our planet.

 

To surmount this difficulty, a team of scientists led by planetary scientist Motohiko Murakami of ETH Zurich in Switzerland irradiated a single crystal of bridgmanite with pulsed lasers, simultaneously increasing its temperature to 2,440 Kelvin and pressure to 80 gigapascals, close to what we know to be the conditions in the lower mantle – up to 2,630 Kelvin and 127 gigapascals of pressure.

“This measurement system let us show that the thermal conductivity of bridgmanite is about 1.5 times higher than assumed,” Murakami said.

In turn, this means that the heat flow from the core to the mantle is higher than we thought – and, therefore, that the rate at which Earth’s interior is cooling is faster than we thought.

And the process could be accelerating. When it cools, bridgmanite transforms into another mineral called post-perovskite, which is even more thermally conductive and would therefore increase the rate of heat loss from the core into the mantle.

“Our results could give us a new perspective on the evolution of Earth’s dynamics,” Murakami said. “They suggest that Earth, like the other rocky planets Mercury and Mars, is cooling and becoming inactive much faster than expected.”

As for exactly how much faster, that’s unknown. The cooling of an entire planet isn’t something we understand very well. Mars is cooling a bit faster because it’s significantly smaller than Earth, but there are other factors that may play a role in how rapidly the planetary interior cools.

For example, the decay of radioactive elements can generate heat, enough to sustain volcanic activity. Such elements are one of the major sources of heat in Earth’s mantle, but their contribution isn’t well understood.

“We still don’t know enough about these kinds of events to pin down their timing,” Murakami said.

However, it likely won’t be a fast process on human scales, either way it falls. In fact, it’s possible that Earth will become uninhabitable by other mechanisms long before then. So we might have a bit of time to work more on the problem to figure it out.

The team’s research has been published in Earth and Planetary Science Letters.

 

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World

Australia records highest temperature in 62 years

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SINGAPORE, Jan 14 (Reuters) – Another day, another heat record.

Australian authorities warned people to stay indoors on Friday as a severe heatwave along the northwestern coast pushed temperatures to a blistering 50.7 degrees Celsius (123 degrees Fahrenheit), hitting a high last seen 62 years ago.

Climate scientists and activists have raised alarm bells that global warming due to human-driven greenhouse gas emissions, especially from fossil fuels, is close to spiralling out of control.

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The planet’s hottest years on record have all been within the last decade, with 2021 being the sixth-hottest, data from the U.S. National Oceanic and Atmospheric Administration showed this week.

An iron ore mining region in the northwest, Australia’s Pilbara, where temperatures hit the record high on Thursday, is known for its hot and dry conditions, with temperatures usually hovering in the upper thirties this time of year.

A camel train carries tourists on a sunset safari along Cable Beach located near the northwestern Australian town of Broome May 17, 2013. REUTERS/Julius Hunter

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Australia is one of the world’s biggest carbon emitters per capita, but the government has refused to back down from its reliance on coal and other fossil fuel industries, saying to do so would cost jobs.

Scientists have found that rising temperatures can hit public health and outdoor labour productivity, resulting in billions of dollars in economic losses.

Australia lost an average of A$10.3 billion ($7.48 billion) and 218 productive hours every year in the last two decades because of heat, according to a global study published this week by researchers at Duke University. These losses will only deepen in the coming decades as the world heads toward global warming of 1.5 degrees above pre-industrial times, they warned.

“These results imply that we don’t have to wait for 1.5°C of global warming to experience impacts of climate change on labour and the economy … Additional future warming magnifies these impacts,” said lead author Luke Parsons.

($1 = 1.3763 Australian dollars)

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Editing by Karishma Singh

Our Standards: The Thomson Reuters Trust Principles.

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Science

Scientists Smash Temperature Record on Keeping ‘Freezing Cold’ Water in Liquid Form

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Scientists have just proven that the freezing temperature of water can be even lower than what we thought was possible.

Taking tiny droplets of water, up to just 150 nanometers in size, a team of engineers at the University of Houston has pushed the critical temperature threshold to -44 degrees Celsius (-47.2 degrees Fahrenheit) – and, more saliently, accurately measured it.

 

Not just a fun thing to brag about at engineering parties, this achievement can now help us to better understand how water freezes, which has implications for a range of scientific fields, from meteorology to cryopreservation.

“Experimental probing of the freezing temperature of few-nanometer water droplets has been an unresolved challenge,” says mechanical engineer Hadi Ghasemi of the University of Houston, Texas.

“Here, through newly developed metrologies, we have been able to probe freezing of water droplets from micron scale down to 2 nm scale.”

Most of us don’t think about water very much, because it’s so ubiquitous and essential for our very existence. But common H2O is actually pretty weird; it doesn’t behave like any other liquid. Even the way it freezes is weird: where other liquids increase in density as they cool, water actually becomes less dense as it freezes.

Water’s behavior has been fairly well characterized and studied. We know, for example, that it tends to nucleate, or form ice crystals, at a variety of temperatures, sometimes resisting the process as far as -38 degrees Celsius. Any colder, and even the most stubborn water molecules will stick together as ice.

 

Ghasemi and colleagues pushed that temperature downwards by placing nanodroplets of water on a soft surface, like a gel or a lipid. Then, they probed the droplets using electrical resistance metrology and Fourier transform infrared spectroscopy to take their temperature as they froze.

The soft interface between the surface and the tiny droplet seemed to play a role in the suppression of ice nucleation, possibly because of the way the interface generates a large pressure on the droplet.

This is because the freezing temperature of water drops as ambient pressure rises. The most pronounced effect was seen in a droplet of water just 2 nanometers across.

“We found that if a water droplet is in contact with a soft interface, freezing temperature could be significantly lower than hard surfaces,” Ghasemi explains.

“Also, a few-nanometer water droplet could avoid freezing down to -44 degrees Celsius if it is in contact with a soft interface.”

The way tiny water droplets freeze is vitally important to cryopreservation, since the freezing of tiny droplets within cells can cause those cells to rupture and die. Learning how to slow or halt that process could help scientists find ways to mitigate that effect.

 

It could also help us better understand how nucleation happens in the atmosphere, where microscopic droplets of water freeze. And it could also help us to better design technology that suffers from ice exposure, such as aircraft and wind turbines, the researchers said.

“The findings are in good agreement with predictions of classical nucleation theory. This understanding contributes to a greater knowledge of natural phenomena and rational design of anti-icing systems for aviation, wind energy, and infrastructures and even cryopreservation systems,” they write in their paper.

“The findings provide an understanding of various natural phenomena and provide a route for the design of superior anti-icing biomimetics or smooth liquid-infused surfaces.”

The research has been published in Nature Communications.

 

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Science

The Hottest White Dwarf We Know of Is Up to Something Ghoulish With Its Neighbor

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There’s a dead star behaving very oddly 1,300 light-years away.

It’s a white dwarf named KPD 0005+5106, and X-ray data from the Chandra space telescope have revealed that it’s enacting extreme violence on an orbiting companion. Not only is it siphoning material from this object (which, to be fair, is pretty normal for white dwarfs), the star is giving its companion an absolute drubbing by blasting it with radiation from close proximity.

 

Even more interestingly, we can’t see what the companion actually is, making it tricky to predict its eventual fate, including how long it will take to be completely destroyed and what that will mean for the white dwarf.

“We didn’t know this white dwarf had a companion before we saw the X-ray data,” said astronomer You-Hua Chu of the Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA) in Taiwan. “We’ve looked for the companion with optical light telescopes but haven’t seen anything, which means it is a very dim star, a brown dwarf, or a planet.”

White dwarfs are what happens to a star under about eight times the mass of the Sun once it runs out of elements it can fuse in its core. As the fuel runs low, it will eject its outer layers into space until finally, the core is no longer able to support itself and collapses under its own gravity into a dense object about the size of Earth (and sometimes even smaller).

Although it may be without fuel to fuse, the white dwarf remains extremely hot, so hot that it will continue to shine brightly with thermal radiation for billions of years. The average white dwarf will have a temperature of over 100,000 Kelvin (99,727 degrees Celsius or 179,540 degrees Fahrenheit) once its core stops contracting. The Sun, for context, has an effective temperature of 5,772 Kelvin.

 

KPD 0005+5106 is an outlier. It’s the hottest white dwarf we’ve identified to date, with an effective temperature of 200,000 Kelvin. This makes it very interesting to scientists since it allows them to probe the limits of what’s possible in the Universe.

Researchers also KPD 0005+5106 observed exhibiting some unusual X-ray activity, so Chu and her team decided to take a closer look using Chandra. They found that the white dwarf increases and decreases in X-ray brightness on a regular basis, every 4.7 hours.

We know of at least one thing that can cause changes in the brightness of a white dwarf: if it’s stripping material from a companion object. That material will be siphoned down to the white dwarf, where it will make its way to the poles and glow brightly. As the star and its companion orbit each other, the hot spot moves in and out of view, causing variations in brightness.

That 4.7-hour period thus would correspond with the system’s orbital period – which would make them very close together indeed. According to the team’s calculations, the white dwarf and its companion would be separated by a distance of just 1.3 times the Sun’s radius. That’s around 900,000 kilometers (550,000 miles). That would mean insanely scorching temperatures.

 

“Whatever this object is,” said astronomer Jesús Toala of the National Autonomous University of Mexico, “it’s getting blasted with heat.”

The researchers investigated possible identities for the companion and concluded that it was most likely an exoplanet with a mass around that of Jupiter. Previous research has found that exoplanets can indeed be found around white dwarfs – if they’re distant enough during the red giant phase, they can survive the star’s transition, then migrate inwards. More than one candidate gas giant has been found orbiting a white dwarf.

According to the team’s models, however, this particular gas giant doesn’t have much longer to live, only a few hundred million years. The white dwarf would be gravitationally stripping it; this stripped material would form a ring around the star and be slowly slurped down onto it.

“This is a slow demise for this object that’s basically being ripped apart by constant gravitational forces,” said astrophysicist Martín Guerrero of The Institute of Astrophysics of Andalusia in Spain. “It would be a very unpleasant place to be.”

The team also studied two other white dwarf stars that display peculiar X-ray behavior. Although these other two stars were not quite as extreme as KPD 0005+5106, their behavior was similar, suggesting that they, too, have unseen companion objects.

This suggests that exoplanet survival around a white dwarf may be more common than we thought – although not, perhaps, for very long.

The team’s research was published earlier this year in The Astrophysical Journal.

 

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Health

What’s Behind The Strange Drop in American Body Temperatures Over The Past 200 Years?

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The human body is often said to rest at a healthy internal temperature of 37 degrees Celsius, or 98.6 degrees Fahrenheit.

This average was established two centuries ago in France, and yet in the meantime, it seems our ‘normal’ physiology has changed ever so slightly.

 

Early last year, researchers in the United States combed Civil War veteran records and national health surveys and found temperatures among men born at the turn of this century were 0.59 degrees Celsius cooler than those men born around two hundred years earlier.

Women, on the other hand, had seen a 0.32 degrees Celsius decline since the 1890s. 

At the time, the authors suggested it might have something to do with inflammation due to disease, which is closely tied to body temperature. With the rise of modern medicine, we’ve seen a decline in chronic infections, and maybe, the authors suggested, this has chilled us out, so to speak.

Later in 2020, another group of researchers found an eerily similar reduction in body temperature among a relatively remote indigenous tribe in Bolivia, where infections have remained widespread and medical care minimal, despite some modern changes.

The reasons for the recent decline in body temperature clearly had to go beyond improved hygiene, cleaner water, or improved medical care, and some researchers at Harvard are now investigating another explanation: a decline in physical activity.

 

When a person exercises regularly, it often coincides with an increase in their metabolism. This, in turn, can raise their body’s resting temperature for hours or even up to a day, which means falling body temperature measurements might indicate falling physical activity. 

Unfortunately, the methods we have for measuring physical activity today weren’t around 200 years ago, so we can’t really compare how we move now to how we moved then.

What could be possible, however, is to use historical body temperature data as a “thermometer” to gauge physical activity before we started keeping track of these things.

If we can model the relationships between physical activity, metabolism, and body temperature we could theoretically work backward.

The idea started as a “back-of-the-envelope” calculation among Harvard researchers, and while their “first pass estimate” is a good start, it’s still based on a bunch of assumptions. That said, it is an intriguing hypothesis.

The model the researchers ultimately created found every 1°C increase in historical body temperature is linked to an approximate 10 percent change in resting metabolic rate.

 

Given how much male body temperatures seem to have decreased since the 1820s, their metabolic rate must have therefore declined by 6 percent in the same time.

That’s equivalent to about half an hour of physical activity a day, according to the authors’ calculations. More precisely, a 27-minute fast walk or slow run for a 75-kilogram (165-pound) male.

“This is a first pass estimate of taking physiological data and trying to quantify declines in activity,” explains skeletal biologist Andrew Yegian from Harvard University.

“The next step would be to try to apply this as a tool to other populations.”

Because these initial estimates use body temperature as a proxy for metabolic activity and then metabolic activity as a proxy for physical activity, it’s very unlikely that these results are not truly representative of the reality.

The rate at which a population metabolizes calories can be pinned down to more than just physical activity, although it is undoubtedly true the average American today exercises less than they did 50 years ago, thanks to automobiles, televisions, and the dawn of the desk job.

It’s just less clear what that’s doing to our metabolisms and the temperature of our bodies. And it might not be the same for men and women.

“Fat also acts as an insulator, affecting heat dissipation from the body, while also increasing the cost of PA, and our estimation methods did not correct for changes in fat mass over time,” the authors write.

A reduced need to thermoregulate in modern environments could also be impacting our metabolic rates, as could improved health and nutrition.

The authors admit their calculations need further refinement, but they hope their approximation will serve “as an anchor for understanding how the decline in physical activity affected health and morbidity during the industrial era.” 

The study was published in Current Biology. 

 

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Technology

Google Camera color temperature slider arrives on Pixel 6

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The revamped camera hardware on the Pixel 6 series delivers better overall shots that are stunning on their own and seem to catch up with the iPhone 13 in big ways, but it doesn’t come down just to hardware. Alongside new motion features, the Pixel 6 also adds a color temperature slider to the Google Camera app.

Available on the Pixel 6 and Pixel 6 Pro, this new color temperature slider in the Google Camera app works alongside the contrast and brightness sliders on the other side of the interface. The slider, as you might expect, adjusts the color temperature of the scene to make it warmer or cooler to suit the shot you need.

The effect can be rather dramatic at its highest levels, but it can help in adjusting the temperature in scenes that need it. As mentioned in our review, this is a feature I didn’t find necessary over the time I’ve had with the phone so far, but I’d imagine it might come in handy in harshly lit scenes such as parties where specialized colored lighting is in use.

Notably, too, the codename for this feature is called “chameleon.” At this point in time, we’re not 100% sure if Google plans to bring this to other Pixel phones, as it may be tied to the new Tensor chip.

Pixel 6 is shipping now from the Google Store and other major retailers.

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