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Science

Earth can regulate its own temperature over m

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The Earth’s climate has undergone some big changes, from global volcanism to planet-cooling ice ages and dramatic shifts in solar radiation. And yet life, for the last 3.7 billion years, has kept on beating.

Now, a study by MIT researchers in Science Advances 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.

Just how does it 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.

Scientists have long suspected 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 there’s never been direct evidence for the continual operation of such a feedback, until now.

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.

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. This stabilizing feedback would explain how the Earth has remained habitable through dramatic climate events in the geologic past.

“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.”

This research was supported in part by a MathWorks fellowship and the National Science Foundation.

###

Written by Jennifer Chu, MIT News Office

Article Title

Presence or absence of stabilizing Earth system feedbacks on different timescales

Article Publication Date

16-Nov-2022

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Science

Earth can regulate its own temperature over millennia, new study finds

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Credit: CC0 Public Domain

The Earth’s climate has undergone some big changes, from global volcanism to planet-cooling ice ages and dramatic shifts in solar radiation. And yet life, for the last 3.7 billion years, has kept on beating.

Now, a study by MIT researchers in Science Advances 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.

Just how does it 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.

Scientists have long suspected 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 there’s never been direct evidence for the continual operation of such a feedback, until now.

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.

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. This stabilizing feedback would explain how the Earth has remained habitable through dramatic climate events in the geologic past.

“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.”

More information:
Constantin Arnscheidt, Presence or absence of stabilizing Earth system feedbacks on different timescales, Science Advances (2022). DOI: 10.1126/sciadv.adc9241

Provided by
Massachusetts Institute of Technology

This story is republished courtesy of MIT News (web.mit.edu/newsoffice/), a popular site that covers news about MIT research, innovation and teaching.

Citation:
Earth can regulate its own temperature over millennia, new study finds (2022, November 16)
retrieved 16 November 2022
from https://phys.org/news/2022-11-earth-temperature-millennia.html

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Science

Length of REM Sleep Linked to Body Temperature

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According to new research from UCLA, the length of REM sleep is linked to animals’ body temperature, with higher body temperatures associated with lower amounts of REM sleep.

Warm-blooded animal groups with lower body temperatures have more rapid eye movement (REM) sleep, while those with higher body temperatures have lower amounts of REM sleep. This is according to new research from Jerome Siegel, a University of California, Los Angeles (UCLA) professor who said his study suggests that REM sleep acts like a “thermostatically controlled brain heater.”

REM sleep first occurs about 90 minutes after falling asleep. Behind closed eyelids, your eyes dart rapidly from side to side. Mixed frequency brain wave activity becomes closer to that seen in wakefulness. Your breathing becomes faster and irregular, and your heart rate and blood pressure increase to near waking levels. Most of your dreaming occurs during REM sleep, although some can also occur in non-REM sleep. Your arm and leg muscles become temporarily paralyzed, which prevents you from acting out your dreams. As you age, less of your time sleeping is spent in REM sleep.

Siegel says the findings suggest a previously unobserved relationship between body temperature and REM sleep, a period of sleep when the brain is highly active. Published recently in Lancet Neurology, the study was authored by Prof. Siegel, who directs the Center for Sleep Research at the Jane and Terry Semel Institute for Neuroscience and Human Behavior at UCLA.

Birds have the highest body temperature of any warm-blooded, or homeotherm, animal group at 41°C (106°F) while getting the least REM sleep at 0.7 hours per day. That’s followed by humans and other placental mammals (37°C/99°F), 2 hours of REM sleep), marsupials (35°C/95°F, 4.4 hours of REM sleep), and monotremes (31°C/88°F, 7.5 hours of REM sleep).

Brain temperature falls in non-REM sleep and then rises in REM sleep that typically follows. This pattern “allows homeotherm mammals to save energy in non-REM sleep without the brain getting so cold that it is unresponsive to threat,” Siegel said.

The amount of humans’ REM sleep is neither high nor low compared to other homeotherm animals, “undermining some popular views suggesting a role for REM sleep in learning or emotional regulation,” he said.

Reference: “Sleep function: an evolutionary perspective” by Jerome M Siegel, PhD, 1 October 2022,



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Science

Princeton Physicists Discover Exotic Quantum State at Room Temperature

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Researchers at Princeton found that a material known as a topological insulator, made from the elements bismuth and bromine, exhibit specialized quantum behaviors normally seen only under extreme experimental conditions of high pressures and temperatures near absolute zero. Credit: Shafayat Hossain and M. Zahid Hasan of Princeton University

For the first time, physicists have observed novel quantum effects in a topological insulator at room temperature.

Researchers at

Physicists have observed novel quantum effects in a topological insulator at room temperature for the first time. This breakthrough came when scientists from Princeton University explored a topological material based on the element bismuth. The study was published as the cover article of the October issue of the journal Nature Materials.

While scientists have used topological insulators to demonstrate quantum effects for more than a decade, this experiment is the first time these effects have been observed at room temperature. Inducing and observing quantum states in topological insulators typically requires temperatures around absolute zero, which is equal to minus 459 degrees

In recent years, the study of topological states of matter has attracted considerable attention among physicists and engineers. In fact, it is presently the focus of much international interest and research. This area of study combines quantum physics with topology — a branch of theoretical mathematics that explores geometric properties that can be deformed but not intrinsically changed.

M. Zahid Hasan. Credit: Princeton University

“The novel topological properties of matter have emerged as one of the most sought-after treasures in modern physics, both from a fundamental physics point of view and for finding potential applications in next-generation quantum engineering and nanotechnologies,” said M. Zahid Hasan, the Eugene Higgins Professor of Physics at Princeton University, who led the research. “This work was enabled by multiple innovative experimental advances in our lab at Princeton,” added Hasan.

A topological insulator is the main device component used to investigate the mysteries of quantum topology. This is a unique device that acts as an insulator in its interior, which means that the electrons inside are not free to move around and therefore do not conduct electricity. However, the electrons on the device’s edges are free to move around, meaning they are conductive. Moreover, because of the special properties of topology, the electrons flowing along the edges are not hampered by any defects or deformations. This device has the potential not only of improving technology but also of generating a greater understanding of matter itself by probing quantum electronic properties.

Until now, however, there has been a major stumbling block in the quest to use the materials and devices for applications in functional devices. “There is a lot of interest in topological materials and people often talk about their great potential for practical applications,” said Hasan, “but until some macroscopic quantum topological effect can be manifested at room temperature, these applications will likely remain unrealized.”

This is because ambient or high temperatures create what physicists call “thermal noise,” which is defined as a rise in temperature such that the atoms begin to vibrate violently. This action can disrupt delicate quantum systems, thereby collapsing the quantum state. In topological insulators, in particular, these higher temperatures create a situation in which the electrons on the surface of the insulator invade the interior, or “bulk,” of the insulator, and cause the electrons there to also begin conducting, which dilutes or breaks the special quantum effect.

The way around this is to subject such experiments to exceptionally cold temperatures, typically at or near absolute zero. At these incredibly low temperatures, atomic and subatomic particles cease vibrating and are consequently easier to manipulate. But creating and maintaining an ultra-cold environment is impractical for many applications; it is costly, bulky, and consumes a considerable amount of energy.

However, Hasan and his team have developed an innovative way to bypass this problem. Building on their experience with topological materials and working with many collaborators, they fabricated a new kind of topological insulator made from bismuth bromide (chemical formula α-Bi4Br4), which is an inorganic crystalline compound sometimes used for water treatment and chemical analyses.

“This is just terrific that we found them without giant pressure or an ultra-high magnetic field, thus making the materials more accessible for developing next-generation quantum technology,” said Nana Shumiya, who earned her Ph.D. at Princeton, is a postdoctoral research associate in electrical and computer engineering, and is one of the three co-first authors of the paper.

She added, “I believe our discovery will significantly advance the quantum frontier.”

The discovery’s roots lie in the workings of the quantum Hall effect — a form of topological effect that was the subject of the Nobel Prize in Physics in 1985. Since that time, topological phases have been intensely studied. Many new classes of quantum materials with topological electronic structures have been found, including topological insulators, topological superconductors, topological magnets, and Weyl semimetals.

While experimental discoveries were rapidly being made, theoretical discoveries were also progressing. Important theoretical concepts on two-dimensional (2D) topological insulators were put forward in 1988 by F. Duncan Haldane, the Sherman Fairchild University Professor of Physics at Princeton. He was awarded the Nobel Prize in Physics in 2016 for theoretical discoveries of topological phase transitions and a type of 2D topological insulators. Subsequent theoretical developments showed that topological insulators can take the form of two copies of Haldane’s model based on electron’s spin-orbit interaction.

Hasan and his team have been on a decade-long search for a topological quantum state that may also operate at room temperature, following their discovery of the first examples of three-dimensional topological insulators in 2007. Recently, they found a materials solution to Haldane’s conjecture in a kagome lattice magnet that is capable of operating at room temperature, which also exhibits the desired quantization.

“The kagome lattice topological insulators can be designed to possess relativistic band crossings and strong electron-electron interactions. Both are essential for novel magnetism,” said Hasan. “Therefore, we realized that kagome magnets are a promising system in which to search for topological magnet phases, as they are like the topological insulators that we discovered and studied more than ten years ago.”

“A suitable atomic chemistry and structure design coupled to first-principles theory is the crucial step to make topological insulator’s speculative prediction realistic in a high-temperature setting,” said Hasan. “There are hundreds of topological materials, and we need both intuition, experience, materials-specific calculations, and intense experimental efforts to eventually find the right material for in-depth exploration. And that took us on a decade-long journey of investigating many bismuth-based materials.

Insulators, like semiconductors, have what are called insulating, or band, gaps. These are in essence “barriers” between orbiting electrons, a sort of “no-man’s-land” where electrons cannot go. These band gaps are extremely important because, among other things, they provide the lynchpin in overcoming the limitation of achieving a quantum state imposed by thermal noise. They do this if the width of the band gap exceeds the width of the thermal noise. But too large a band gap can potentially disrupt the spin-orbit coupling of the electrons — this is the interaction between the electron’s spin and its orbital motion around the nucleus. When this disruption occurs, the topological quantum state collapses. Therefore, the trick in inducing and maintaining a quantum effect is to find a balance between a large band gap and the spin-orbit coupling effects.

Following a proposal by collaborators and co-authors Fan Zhang and Yugui Yao to explore a type of Weyl metals, Hasan and his team studied the bismuth bromide family of materials. But the researchers were not able to observe the Weyl phenomena in these materials. They instead discovered that the bismuth bromide insulator has properties that make it more ideal compared to a bismuth-antimony-based topological insulator (Bi-Sb alloys) that they had studied before. It has a large insulating gap of over 200 meV (“milli electron volts”). This is large enough to overcome thermal noise, but small enough so that it does not disrupt the spin-orbit coupling effect and band inversion topology.

“In this case, in our experiments, we found a balance between spin-orbit coupling effects and large band gap width,” said Hasan. “We found there is a ‘sweet spot’ where you can have relatively large spin-orbit coupling to create a topological twist as well as raise the band gap without destroying it. It’s kind of like a balance point for the bismuth-based materials that we have been studying for a long time.”

When the researchers viewed what was going on in the experiment through a sub-atomic resolution scanning tunneling microscope, they knew they had achieved their goal. This microscope is a unique device that uses a property known as “quantum tunneling,” where electrons are funneled between the sharp metallic, single-

This finding is the culmination of many years of hard-won experimental work and required additional novel instrumentation ideas to be introduced in the experiments. Hasan has been a leading researcher in the field of experimental quantum topological materials with novel experimentation methodologies for over 15 years; and, indeed, was one of the field’s early pioneer researchers. Between 2005 and 2007, for example, he and his team of researchers discovered topological order in a three-dimensional bismuth-antimony bulk solid, a semiconducting

These studies will require the development of another set of new instrumentations and techniques to fully harness the enormous potential of these materials. “I see a tremendous opportunity for further in-depth exploration of exotic and complex quantum phenomena with our new instrumentation, tracking more finer details in macroscopic quantum states,” Hasan said. “Who knows what we will discover?”

“Our research is a real step forward in demonstrating the potential of topological materials for energy-saving applications,” added Hasan. “What we’ve done here with this experiment is plant a seed to encourage other scientists and engineers to dream big.”

Reference: “Evidence of a room-temperature quantum spin Hall edge state in a higher-order topological insulator” by Nana Shumiya, Md Shafayat Hossain, Jia-Xin Yin, Zhiwei Wang, Maksim Litskevich, Chiho Yoon, Yongkai Li, Ying Yang, Yu-Xiao Jiang, Guangming Cheng, Yen-Chuan Lin, Qi Zhang, Zi-Jia Cheng, Tyler A. Cochran, Daniel Multer, Xian P. Yang, Brian Casas, Tay-Rong Chang, Titus Neupert, Zhujun Yuan, Shuang Jia, Hsin Lin, Nan Yao, Luis Balicas, Fan Zhang, Yugui Yao and M. Zahid Hasan, 14 July 2022, Nature Materials.
DOI: 10.1038/s41563-022-01304-3

The team included numerous researchers from Princeton’s Department of Physics, including present and past graduate students Nana Shumiya, Maksim Litskevich, Yu-Xiao Jiang, Zi-Jia Cheng, Tyler Cochran and Daniel Multer, and present and past postdoctoral research associates, Shafayat Hossain, Jia-Xin Yin and Qi Zhang. Other co-authors were Zhiwei Wang, Chiho Yoon, Yongkai Li, Ying Yang, Guangming Cheng , Yen-Chuan Lin, Brian Casas, Tay-Rong Chang, Titus Neupert , Zhujun Yuan, Shuang Jia , Hsin Lin  and Nan Yao .

The work at Princeton was supported by the U.S. Department of Energy’s Basic Energy Sciences Division (and the Gordon and Betty Moore Foundation’s Emergent Phenomena in Quantum Systems Initiative.



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US

S.F. Bay Area records highest-ever temperature

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What’s behind the sizzling temperatures? It’s called a heat dome: an atmospheric lid is trapping hot air over the Western U.S., triggering intense heat. You can read more here about the science of California’s worsening heat waves, as explained by the Chronicle weather science team.

Our reporters are fanning out today to bring you the latest news from around the Bay Area.

Latest updates:

Power grid emergency intensifies

The California grid moves to higher emergency alert level

From 6:30 p.m. to 9 p.m. the California grid will move to Energy Emergency Alert Level 2 — the highest level of emergency so far in this heat wave. If the grid moves through Emergency Alert Level 3, it will turn turn to rolling blackouts as demand overwhelms supply. 

Bay Area school district cuts hours at three schools

Novato Unified School District will run a compressed schedule at Lu Sutton Elementary School, Novato High School and Hill Education Center, schools that have limited or no air-conditioning, during Marin County’s excessive heat warning from Tuesday to Friday. At the high school, each period will be shortened and the school day will finish by 1:15 p.m.

Preliminary heat records shattered across Bay Area

Preliminary high temperatures for the Bay Area’s scorching heat wave are rolling in, and early reports show Livermore possibly soared to 113 to 116 degrees, which would break its daily record high of 108 degrees that was set in 1950. Buchanan Field Airport in Concord tied its all-time record of 112 degrees from 2020, while downtown Oakland reached 100 degrees, breaking its daily record high of 95 degrees in 2008.

The San Francisco Airport tied its daily record high of 93 degrees from 2020. A high of 102 degrees was recorded both at San Jose International Airport and in Mountain View, breaking the previous daily record highs of 99 and 97 degrees in 2009, respectively. Palo Alto reached 98 degrees, breaking the 2008 daily record high of 95 degrees.

The Sonoma County Airport station hit a high of 111 degrees, breaking the 109-degree daily record set two years ago. The Napa County Airport reached 109 degrees, surpassing the 106-degree record in 2020. The National Weather Service Bay Area office will start verifying the records Monday afternoon, but it is unclear when a final report will go out.

Fairfield temps, already at record, could go even higher on Tuesday

Fairfield, in the Travis AFB area, preliminarily recorded a high of 116 degrees — an all-time record for the Bay Area. The city’s temperatures could go higher still on Tuesday, according to Chronicle meteorologist Gerry Diaz. Livermore was another city that saw excruciating temperatures on Tuesday.

California grid declares first stage of emergency for Tuesday

Even as the grid veered toward a power shortage on Monday, officials preemptively declared another emergency on Tuesday from 5 to 9 p.m. Power demand is expected to reach its highest-ever levels on Tuesday, causing the specter of rolling blackouts to linger over California.

A bank sign reads 106 degrees at 4:25pm on 4th Street in San Rafael, Calif., on Monday, September 5, 2022.Scott Strazzante/The Chronicle

Fairfield records Bay Area’s highest-ever temperature

Fairfield hit 116 degrees late Monday afternoon which — assuming the number is finalized by the National Weather Service — would be the highest temperature ever recorded in the nine-county Bay Area, according to Chronicle meteorologist Gerry Diaz. The weather service will begin to verify records on Monday afternoon. The figure was recorded in the vicinity of Travis Air Force Base.

Flex Alert takes effect at 4 p.m.

The California grid operator’s request that Californians reduce their electricity use — a request known as a Flex Alert — is now in effect. Californians are asked to refrain from using energy-hungry appliances such as the dryer or dishwasher, turn out unneeded lights and keep their air conditioning to 78 degrees or higher (85 for those who are not at home). The goal is to prevent rolling blackouts, which could happen if the grid is overtaxed by electricity loads. Regulators have said Monday will be the most challenging day for the grid so far during this heat wave.

A young girl tries to stay cool in the stands at the Scottish Highland Games in Pleasanton on Sunday. Monday is expected to be even hotter.

Brittany Hosea-Small/Brittany Hosea-Small / Special to The Chronicle

Storms possible next weekend

Tropical storm Kay is spinning off the southern coast of Baja California Sur, and is forecast to hit Baja as a hurricane by the middle of the week. Its remnants will bring plenty of moisture into Southern California. This moisture will help spawn scattered wet thunderstorms from San Diego to Santa Barbara, along with portions of Kern County and the Mojave, according to Chronicle meteorologist Gerry Diaz. The latest weather models are signaling that some of this remnant moisture will make it into NorCal next weekend as well. If enough moves in, Northern California could see wet storms as well. But if only sprinkles of remnant moisture move in, the chance for these storms producing dry lightning in the heat-strained forests of Northern California next weekend cannot be ruled out.

Parts of Bay Area see power outages

Up to 5,000 homes and businesses were without power in Napa County, as were more than 5,000 in an area west of Vacaville, according to a PG&E outage map. The utility could not immediately be reached for an explanation, but extreme heat is known to strain all infrastructure, including power equipment. The outages are not part of statewide rolling blackouts, which are a possibility — though not an inevitability — for the late afternoon and evening Monday. 

Callifornia regulators watching for outdoor work violations

Cal/OSHA has told companies in the construction, agriculture, tree-trimming, landscaping, car wash and warehouse fields that it plans to conduct “targeted inspections” to ensure workers safety during the heat wave. By law, employers must supply fresh water, access to shade and regular breaks — and closely monitor employees for signs of heat illness at extreme temperatures.

Construction worker Gabriel Caballero drinks water while working along Fitzuren Road as temperatures rise in Antioch, Calif. Thursday, Sept. 1, 2022.Jessica Christian/The Chronicle

‘Rolling blackouts are a possibility today,’ grid chief says

The nearly unprecedented strain on the power grid will peak on Monday and Tuesday, with grid officials looking at all possible ways to avert rolling blackouts. The best thing Californians can do, they say, is slash electricity use from 4 p.m. to 10 p.m. on Monday night (and similar hours this week), to offset the immense power demand from air conditioners. Read more here about how the public can help avert blackouts.

Sacramento Valley projected to see record highs of up to 119 degrees

The heat wave in the Sacramento Valley is reaching its apex today and tomorrow, meaning it’s about to experience some of the hottest temperatures seen in the continental United States this year. Weather models are projecting today’s highs reaching 115-119 degrees, according to Chronicle meteorologist Gerry Diaz. Sacramento, Modesto and other cities are forecast to surpass their all-time records the next couple of days. Little overnight heat relief is expected, with nighttime temperatures staying in the 70s, while some of the peaks along the Sierra and Diablo Ranges will likely stay in the 80s overnight. Temperatures will finally drop below 110 degrees in most of the valley by Thursday, but 100-105 degree weather will still be rampant from Thursday to Saturday.

Some BART trains running slower due to the heat:

“There is a 10-minute delay on the Antioch Line in the Antioch and SFO directions due to warm weather conditions,” BART said in its alert feed. The service had also slowed down trains on Sunday for the same reason.

110 degree temperatures coming to Wine Country and the East Bay

Chronicle meteorogist Gerry Diaz reports here on which Bay Area cities are likely to hit 110 on Labor Day.

A person jogs under noon rays at Lake Merritt in Oakland on Monday. Heat warnings and advisories have been extended until Thursday.

Santiago Mejia/The Chronicle

Don’t go to Stinson Beach, Marin officials warn

“If you are not already at Stinson Beach. …  we’d suggest not going,” the Marin County Sheriff tweeted Sunday. There are “hours-long delays getting into the area, and the parking lots and street side parking is all full.” On Sunday, the sheriff’s office said it had issued more than 145 citations in Stinson Beach. Visitors are requested not to block driveways or park in yards, and to be respectful of residents.

California lawmakers want to rank heat waves

On the desk of Gov. Gavin Newsom is AB2238, a bill that would direct the state’s Environmental Protection Agency to create a ranking system for heat waves by 2025. Hurricanes, earthquakes and even atmospheric rivers get ranked by their severity — so why not heat waves? It’s unclear how the current heat wave would rank, but officials say its extreme temperatures and long duration make it particularly dangerous. Read more here about the heat wave ranking bill, which was passed unanimously with bipartisan support.

‘Too hot to barbecue’

Along the Russian River near Healdsburg — a city expected to see temperatures of 110 degrees on Monday — Myra Perez of Sonoma joked it might be the hottest she’s ever been. Her children, 6 and 3, played in the water, apparently immune to the heat. “It’s too hot to barbecue,” Perez said. “We’re going to In-N-Out. It’s the type of choice many Californians are facing on what is normally an outdoors-oriented holiday.

Parking lots at Marin Beaches and near Golden Gate Bridge area are full

The Golden Gate National Recreation Area tweeteed that parking lots in Stinson Beach, Muir Beach and Rodeo Beach in Marin County are full, as are most of its lots in San Francisco. “We welcome our visitors escaping the heat, and remind them to be patient, get shade, and don’t take chances with cold ocean currents or coastal bluffs,” the park service tweeted.

As temperatures rise, children play in the water at Crissy Field in San Francisco on Monday.

Scott Strazzante/The Chronicle

Even San Francisco is already experiencing ‘extreme’ heat

Heat in San Francisco is considered extreme when it surpasses 85 degrees – and shortly before noon, the downtown reading was already at 89 degrees. The city will remain cooler than most parts of the sweltering region and state, however.

California grid boss says Tuesday demand expected to be highest ever

Amid scorching temperatures across California, the state’s electrical grid operator is forecasting the highest-ever demand for power in state history. Californians burned through 50,270 megawatts of power on July 24, 2006, but California Independent System Operator President and CEO Elliot Mainzer said Monday at a news conference that the expected demand has surpassed that historic high for Tuesday. He called on Californians to conserve their power during the key hours of 4 p.m. to 10 p.m. this week and hoped that those reductions and importing power from other states could get the state through Monday and Tuesday without rolling blackouts.

California grid issues emergency stage 1 notice

In a sign of the intense stress on power supplies caused by the heat wave, the California grid operator has issued an Energy Emergency Alert 1 notice for Monday, effective from 5 p.m. through 9 p.m. This is the first level-1 emergency alert for the grid so far this heatwave, and it is designed to lower power demand from large customers and create more supply. If the grid passes through emergency stages 2 and 3 — something grid officials think could happen Monday — then it is time for rolling blackouts because demand, sent sky-high by air conditioning use, is exceeding supply. Read more here about the nearly unprecedented strain on California’s power grid.

Fire danger is high across California

Officials are warning against any activity that could start a fire, as the extreme temperatures have further dried out vegetation and made it highly vulnerable to a spark. Fire danger is rated high through Friday in most of California. 

How long will the heat wave last?

What feels like an endless heatwave is peaking on this Labor Day, with widespread 105-110° F temperatures coating the North Bay, East Bay and Sacramento Valley. Even San Francisco is getting in on some of the heat wave as parts of the city climb to the 80s today. This historic heat wave isn’t done with California yet. With the heat wave expected to drag out, all excessive heat warnings and advisories for the Bay Area and the Sacramento Valley have been extended through 8 p.m.. Thursday.

Fans take advantage of the shade while watching San Francisco Giants play the Philadelphia Phillies  at Oracle Park in San Francisco on Sunday.

Scott Strazzante/The Chronicle

Hiker suffering from heat exhaustion rescued from Montara Mountain

Officials rescued a hiker who had experienced heat exhaustion at Montara Mountain in San Mateo County on Sunday, according to a tweet from Cal Fire’s CZU branch. Read here about officials’ warnings about outdoor exertion this weekend, following a string of high-profile heat-related deaths over the past year.

Flex alert in effect Monday from 4 p.m. to 10 p.m.

During that time, electric grid officials are asking Californians to refrain from using energy-intensive appliances such as dryers or dishwashers and turn off unnecessary lights. They also ask people to keep their air conditioning at 78 degrees or higher during that time (pre-cooling your home before 4 p.m. is a good idea). This is the latest in a string of Flex Alerts during the heat wave.

A biker rides by Lake Merritt during the heat wave on Labor Day weekend in Oakland.

Michaela Vatcheva / Special to The Chronicle

Rolling blackouts a possibility on Monday

Power grid conditions are expected to deteriorate late Monday afternoon as air conditioners work overtime and electricity demand soars. Grid officials anticipate emergency conditions and will ask consumers and businesses to save power from 4 to 10 p.m. in a bid to avert rolling blackouts. Read more here about why grid officials are so worried.

What is a heat wave?

Heat waves are typically defined as unusually hot weather lasting more than two days. But what’s considered unusual can vary across California’s distinct geographical regions. For example, a high of 95 degrees Fahrenheit may describe a normal summer day in the Central Valley. But these temperatures could be unbearable in San Francisco, where residents typically don’t have air conditioning. Weather experts consider these differences when providing warnings about extreme heat. Go here to read more about the science of heat waves.

 

 

 

 

 

 

 

 

 

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Science

Matter at extreme conditions of very high temperature and pressure turns out to be remarkably simple and universal

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Credit: Pixabay/CC0 Public Domain

Scientists at Queen Mary University of London have made two discoveries about the behavior of “supercritical matter”—matter at the critical point where the differences between liquids and gases seemingly disappear.

While the behavior of matter at reasonably low temperature and pressure was well understood, the picture of matter at high temperature and pressure was blurred. Above the critical point, differences between liquids and gases seemingly disappear, and the supercritical matter was thought to become hot, dense and homogeneous.

The researchers believed there was new physics yet to be uncovered about this matter at the supercritical state.

By applying two parameters—the heat capacity and the length over which waves can propagate in the system, they made two key discoveries. First, they found that there is a fixed inversion point between the two where matter changes its physical properties—from liquid-like to gas-like. They also found that this inversion point is remarkably close in all systems studied, telling us that the supercritical matter is intriguingly simple and amenable to new understanding.

As well as fundamental understanding of the states of matter and the phase transition diagram, understanding supercritical matter has many practical applications; hydrogen and helium are supercritical in gas giant planets such as Jupiter and Saturn, and therefore govern their physical properties. In green environmental applications, supercritical fluids have also proved to be very efficient at destroying hazardous wastes, but engineers increasingly want guidance from theory in order to improve efficiency of supercritical processes.

Kostya Trachenko, Professor of Physics at Queen Mary University of London, said, “The asserted universality of the supercritical matter opens a way to a new physically transparent picture of matter at extreme conditions. This is an exciting prospect from the point of view of fundamental physics as well as understanding and predicting supercritical properties in green environmental applications, astronomy and other areas.

“This journey is ongoing and is likely to see exciting developments in the future. For example, it invites the question of whether the fixed inversion point is related to conventional higher-order phase transitions? Can it be described by using the existing ideas involved in the phase transition theory, or is something new and quite different needed? As we push the boundaries of what is known, we can identify these new exciting questions and start looking for answers.”

Methodology

The main problem with understanding supercritical matter was that theories of gases, liquids and solids were not applicable. It remained unclear what physical parameters would uncover the most salient properties of the supercritical state.

Armed with earlier understanding of liquids at lower temperature and pressure, researchers used two parameters to describe the supercritical matter.

1. The first parameter is the commonly used property: this is the heat capacity showing how efficiently the system absorbs heat and containing essential information about the system’s degrees of freedom.

2. The second parameter is less common: this is the length over which waves can propagate in the system. This length governs the phase space available to phonons. When this length reaches its smallest value possible and becomes equal to the interatomic separation, something really interesting happens.

The scientists found that in terms of these two parameters, the matter at extreme conditions of high pressure and temperature becomes remarkably universal.

This universality is two-fold. First, the plot of heat capacity vs wave propagation length has a striking fixed inversion point that corresponds to the transition between two physically different supercritical states: liquid-like and gas-like states. On crossing this inversion point, the supercritical matter changes its key physical properties. The inversion point importantly serves as an unambiguous way to separate the two states—something that has occupied the minds of scientists for some time.

Second, the location of this inversion point is remarkably close in all types of systems studied. This second universality is notably different to all other transition points known. For example, two of these transition points—the triple point where all three states of matter (liquid, gas, solid) co-exist and the critical point where the gas-liquid boiling line ends—are different in different systems. On the other hand, the same inversion point in all systems at extreme supercritical conditions tells us that the supercritical matter is intriguingly simple.

Uncovering and proving this simplicity is the main result of the paper, “Double universality of the transition in the supercritical state,” published in Science Advances.

Molecular-scale phase boundaries: A ‘primitive’ liquid-gas transition

More information:
C. Cockrell et al, Double universality of the transition in the supercritical state, Science Advances (2022). DOI: 10.1126/sciadv.abq5183. www.science.org/doi/10.1126/sciadv.abq5183
Provided by
Queen Mary, University of London

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Technology

Samsung Galaxy Watch 5: Everything New, From Better Battery to Skin Temperature Sensors

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What’s happening

Samsung’s newest watches, the Galaxy Watch 5 and Watch 5 Pro, are arriving Aug. 26. They feature better battery life and skin temperature sensors, and promise more durability.

Why it matters

Last year’s Samsung watch was the debut of Google’s new Wear OS, and smartwatches are in search of better battery life. But Google’s Pixel Watch is also coming this fall.

What’s next

Samsung’s preorders for the watch start now, but stay tuned for our full review. Meanwhile, many more competing watches are expected later this year.

The Galaxy Watch 5, revealed at Samsung’s Unpacked event Wednesday, is the company’s latest attempt to make the ultimate Android watch following last year’s Galaxy Watch 4. This time it’s coming with a bigger Pro model to go with it, with both models set for an Aug. 26 release alongside the new Galaxy Buds 2 Pro, Galaxy Fold 4 and Flip 4.

Last year’s watch served as the debut of Google’s new Wear OS 3 — which Samsung co-developed — and while it wasn’t perfect, it included an ambitious bunch of new health sensors that aimed to bring wrist-based bio-impedance and fat measurements to Samsung Health.

2022 is a whole new story. Google has the Pixel Watch arriving this fall, promising a blend of Fitbit and Google automatic smarts and design. Meanwhile, Samsung’s new watches are promising longer battery life over last year, a skin temperature sensor and a supposedly more durable sapphire crystal for the watch face instead of Gorilla Glass. The Pro model’s extra-beefy battery promises days-long wear between charges, a trend that Apple’s reported to follow on its next watch this fall.


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Is the Watch 5 worth getting? Or, the Pro model? Or should you wait to see what the Pixel Watch is all about? Samsung’s first out of the gate on this year’s fall wave of watches, so let’s break down what it’s got. We can’t compare others yet, because they’re not here yet. But Samsung’s latest watch model looks like a more modest upgrade compared to last year, with only a few notable changes to the equation.

More from Samsung Unpacked

Price: A wide range, with some discounts

Samsung’s Bluetooth-only Watch 5 will start at $280 (£269, AU$495), with the LTE version starting at $330. But the bigger-battery titanium-cased Pro model starts at $450 (£394, AU$725), or $500 for the LTE version. Samsung’s offering some trade-in discounts on preorders: $75 off the Watch 5, or $125 off the Pro if an “eligible” watch is traded in, along with a $50 credit for accessories. Other retailers may end up having sales and trade-in discounts, too.

The titanium-cased Pro model has a very large battery, and a higher price.


Lisa Eadicicco/CNET

Battery life: An extra boost

The previous Watch 4 had a 361-mAh battery for the 44mm size, or 247 mAh for the 40mm version. The Watch 5 has a 410-mAh battery in the 44mm size, or 284 mAh in the smaller model. That should theoretically give a bit more battery life, although who knows how much specifically; the last Watch 4 tended to last about two days or so on my wrist.

The bigger jump comes in the new Watch 5 Pro model, which has a huge 590-mAh battery. That could mean three days of battery life, depending on use. Samsung is pitching the oversized Pro (with its higher cost and titanium case) at runners using GPS, or outdoorsy people who might want extra durability and battery life.

Skin temperature: Another watch joins the trend

Samsung’s Watch 5 has the heart rate sensors, bioimpedance electrical sensor and ECG sensor of the previous Watch 4, but the infrared-based skin temperature sensor is new — to Samsung watches, at least. Temperature sensing has been a recent trend in wearables: Fitbit’s watches have had it for a couple of years, Amazon’s Halo bands have it, the Oura ring has it and Apple’s next watch is reported to have it.

Skin temperature will be added to the rest of Samsung’s health metrics to build out different ways to perceive wellness changes, but it’s unclear in what way it might evolve. Based on previous experience with other skin temperature sensors, this is how they work: the results are relative, not specific, focused more on changes over time than any specific thermometer-like reading. I’ve found that it could help pre-sense a possible sickness, but how Samsung uses it remains to be seen.

The look of the Galaxy Watch 5, in general, remains the same.


Lisa Eadicicco/CNET

Design: Familiar (and a bit bigger for the Pro)

The Watch 5 looks to have similar dimensions to the last Watch 4 models, but a few grams heavier for both sizes. Color options include graphite, sapphire, pink gold and silver. 

Meanwhile, the bigger-battery Watch 5 Pro is notably larger, with an extra millimeter in thickness, and extra millimeter-plus in length and width over the 44mm Watch 5. At 46.5 grams, it’s significantly heavier, creeping towards nearly twice the weight of last year’s 40mm Watch 4 (25.9 grams). The titanium case design comes in either black or gray, with a D-buckle on the sport band.

Samsung’s adding a bunch of new watch faces this year, on top of a collection that already were pretty excellent last year. These watch faces and their colors will offer up most of the customized looks for most people, anyway.

One thing that does appear to be gone, though, is that physical rotating bezel that was on the classic Watch 4 design. Samsung’s touch bezel is now the default way of interacting, but the company will keep the Galaxy Watch 4 Classic in the lineup if you want a watch with a physical dial.

More durable?

Samsung has moved to sapphire crystal for the Watch 5, which it’s promised will be 60% harder. Will that mean better scratch resistance, or improved durability from shattering?

The Watch 5 Pro is, of course, promising an even better sapphire crystal, plus a titanium case around the watch (versus aluminum on the regular Watch 5). 

Other specs

Both watches have optional LTE models with cellular onboard (no 5G this year, although no other watch has 5G either), plus 5 ATM of water resistance for swimming. The same array of health sensors are in both models including ECG, heart rate, temperature and bioimpedance sensors. The watches also include 16GB of storage for music or apps, dual-band Wi-Fi and Bluetooth 5.2.

Notably, neither watch uses Qualcomm’s recently announced Snapdragon W5 chip, which promises better battery life and is coming to other Wear OS watches later this year. Instead, Samsung’s using its own dual-core Exynos W920 1.18GHz processor, which looks to be the same as last year’s Watch 4. Watch processors aren’t the sort of things most people eagerly look forward to, and it’s unknown yet how much better Qualcomm’s new chipset could be.

Android only, but more specifically made for Samsung phones

Much like the Galaxy Watch 4 last year (and other new Wear OS 3 watches we know of), the Watch 5 won’t work with iOS. It’s only for Android phones (according to Samsung, Android 8 or higher, with more than 1.5GB of RAM). But, more specifically, its ECG, stress and bioimpedance sensors only work with Samsung phones. Last year, these health features needed Samsung phones to work, too. 

If this remains true, it’s a big limit to how appealing the Watch 5 will be to most Android phone owners: it’s worth waiting for Google’s Pixel Watch, which is expected by the end of the year, to see how its health features compare. The biggest difference with Samsung’s newest watch this year is that it won’t be the only Wear OS 3 watch around anymore.

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Science

Massive volcano eruption could weaken ozone layer: scientists

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The violent eruption of Tonga’s Hunga Tonga-Hunga Ha’apai volcano on Jan. 15, 2022, injected an unprecedented amount of water directly into the stratosphere – enough to fill more than 58,000 Olympic-size swimming pools.

“We’ve never seen anything like it,” said Luis Millán, an atmospheric scientist who works at NASA’s Jet Propulsion Laboratory. 

When the volcano erupted, seawater came into direct contact with erupting lava and was superheated, creating “explosive steam.”

NASA scientists say that the vapor will stay for years, likely affecting the Earth’s global average temperature. Normally the vapor takes around 2-3 years to dissipate, but the water from the Jan. 15 eruption could take 5-10 years to evaporate.

Hunga Tonga-Hunga Ha’apai “may be the first volcanic eruption observed to impact climate not through surface cooling caused by volcanic sulfate aerosols, but rather through surface warming,” Millán hypothesized in a paper.

A photo of the Tonga Geological Services shows the Tonga volcano activity on Jan. 14, days before its main explosion.
Facebook/Tonga Geological Servic
A plume rises over Tonga after eruption on Jan. 15.
NOAA/SSEC/CIMSS via REUTERS
The ash plume from the Hunga Tonga-Hunga Ha’apai the day after the volcanic eruption.
NASA Earth Observatory image by

Millán led a study examining the amount of water vapor that the volcano injected into the stratosphere, the layer of the atmosphere between about 8 and 33 miles (12 and 53 kilometers) above Earth’s surface.

Millán and his colleagues’ found that the Tonga volcano sent around 146 tetragrams (1 tetragram equals a trillion grams) of water vapor into the Earth’s stratosphere. The amount of water launched in the stratosphere is equal to 10% of the water already present in the atmospheric layer. Their research was published in Geophysical Research Letters.

The eruption came from a volcano that is more than 12 miles wide. One day before the massive eruption, Tongan officials reported on Facebook the volcano was continually erupting. In the post, they reported that the volcano was sending a 3 mile-wide column plume of ash, steam and gas rising to an altitude of 35 miles into the atmosphere.

The researchers also noted how the water vapor could weaken the ozone layer that protects life on Earth from damaging radiation from the sun. 

Intact Hunga Tonga-Hunga Ha’apai in 2015.
NASA Earth Observatory image by
Overview of Hunga Tonga Hunga Ha’apai volcano last year.
AP

The study authors said it’s still too early to predict the exact climatic effects of the Tonga eruption. “It is critical to continue monitoring volcanic gases from this eruption and future ones to better quantify their varying roles in climate,” Millán wrote.

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Science

NASA Spacecraft Finds Pits on the Moon That Always Hover Around a Comfortable Temperature

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Artist’s rendering of NASA’s Lunar Reconnaissance Orbiter. Credit: NASA’s Goddard Space Flight Center

Scientists have discovered shaded locations within pits on the Moon that always hover around a comfortable 63 °F (about 17 °C). The

Since pits were first discovered on the Moon in 2009, scientists wondered if they led to caves that could be explored or used as shelters. Besides for the more stable temperatures, the pits or caves could also offer some protection from cosmic rays, solar radiation, and micrometeorites.

“About 16 of the more than 200 pits are probably collapsed lava tubes,” said Tyler Horvath, a doctoral student in planetary science at the University of California, Los Angeles, who led the new research, recently published in the journal Geophysical Research Letters.

Variations in lighting reveal the structure of the fascinating lunar pit craters. The center panel, with the Sun high above, gives scientists a great view of the Maurius Hills pit floor. Each panel is 300 meters wide, left M133207316LE, center M122584310LE, right M114328462RE. Credit: NASA/GSFC/Arizona State University

“Lunar pits are a fascinating feature on the lunar surface,” said LRO Project Scientist Noah Petro of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Knowing that they create a stable thermal environment helps us paint a picture of these unique lunar features and the prospect of one day exploring them.”

Lava tubes, which are also found on Earth, form when molten lava flows beneath a field of cooled lava or a crust forms over a river of lava, leaving a long, hollow tunnel. If the ceiling of a solidified lava tube collapses, it opens a pit that can lead into the rest of the cave-like tube.

Two of the most prominent lunar pits have visible overhangs that clearly lead to caves or voids, and there is strong evidence that another’s overhang may also lead to a large cave.

“Humans evolved living in caves, and to caves we might return when we live on the Moon,” said David Paige, a co-author of the paper who leads the Diviner Lunar Radiometer Experiment aboard LRO that made the temperature measurements used in the study.

Two views of Mare Ingenii pit. Credit: NASA/GSFC/Arizona State University.

Horvath processed data from Diviner – a thermal camera – to find out if the temperature within the pits was different from those on the surface.

Focusing on a roughly cylindrical 328-foot (100-meter)–deep depression about the length and width of a football field in an area of the Moon known as the Mare Tranquillitatis, Horvath and his colleagues used computer modeling to analyze the thermal properties of the rock and lunar dust and to chart the pit’s temperatures over time.

The results revealed that temperatures within the permanently shadowed reaches of the pit fluctuate only slightly throughout the lunar day, remaining quite stable at around 63 °F or 17 °C. If a cave extends from the bottom of the pit, as images taken by LRO’s Lunar Reconnaissance Orbiter Camera suggest, it too would have this relatively comfortable temperature.

Variations in lighting reveal the structure of the fascinating lunar pit craters. The center panel, with the Sun high above, gives scientists a great view of the Maurius Hills pit floor. Each panel is 300 meters wide, left M133207316LE, center M122584310LE, right M114328462RE. Credit: NASA/GSFC/Arizona State University

The team, which included University of California, Los Angeles (UCLA) professor of planetary science David Paige and Paul Hayne of the University of Colorado Boulder, believes the shadowing overhang is responsible for the steady temperature, limiting how hot things gets during the day and preventing heat from radiating away at night.

A day on the Moon lasts about 15 Earth days, during which the surface is constantly bombarded by sunlight and is frequently hot enough to boil water. Brutally cold nights also last about 15 Earth days.

Reference: “Thermal and Illumination Environments of Lunar Pits and Caves: Models and Observations From the Diviner Lunar Radiometer Experiment” by Tyler Horvath, Paul O. Hayne and David A. Paige, 8 July 2022, Geophysical Research Letters.
DOI: 10.1029/2022GL099710

NASA’s Lunar Reconnaissance Orbiter project, Extended Mission 4 funded the research. LRO is managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, for the Science Mission Directorate at NASA Headquarters in Washington. Launched on June 18, 2009, LRO has collected a treasure trove of data with its seven powerful instruments, making an invaluable contribution to our knowledge about the Moon. University of California, Los Angeles, and NASA’s Jet Propulsion Laboratory in Pasadena, California built and developed Diviner.

NASA is returning to the Moon with commercial and international partners to expand human presence in space and bring back new knowledge and opportunities.



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World

UK breaks record for highest temperature as Europe sizzles

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LONDON (AP) — Britain shattered its record for highest temperature ever registered Tuesday amid a heat wave that has seared swaths of Europe, as the U.K.’s national weather forecaster said such highs are now a fact of life in a country ill-prepared for such extremes.

The typically temperate nation was just the latest to be walloped by unusually hot, dry weather that has triggered wildfires from Portugal to the Balkans and led to hundreds of heat-related deaths. Images of flames racing toward a French beach and Britons sweltering — even at the seaside — have driven home concerns about climate change.

The U.K. Met Office weather agency registered a provisional reading of 40.3 degrees Celsius (104.5 degrees Fahrenheit) at Coningsby in eastern England — breaking the record set just hours earlier. Before Tuesday, the highest temperature recorded in Britain was 38.7 C (101.7 F), set in 2019. By later afternoon, 29 places in the UK had broken the record.

As the nation watched with a combination of horror and fascination, Met Office chief scientist Stephen Belcher said such temperatures in Britain were “virtually impossible” without human-driven climate change.

He warned that “we could see temperatures like this every three years” without serious action on carbon emissions.

The sweltering weather has disrupted travel, health care and schools. Many homes, small businesses and even public buildings, including hospitals, in Britain don’t have air conditioning, a reflection of how unusual such heat is in the country better known for rain and mild temperatures.

The intense heat since Monday has damaged the runway at London’s Luton airport, forcing it to shut for several hours, and warped a main road in eastern England, leaving it looking like a “skatepark,” police said. Major train stations were shut or near-empty Tuesday, as trains were canceled or ran at low speeds out of concern rails could buckle.

London faced what Mayor Sadiq Khan called a “huge surge” in fires because of the heat. The London Fire Brigade listed 10 major blazes it was fighting across the city Tuesday, half of them grass fires. Images showed several houses engulfed in flames as smoke billowed from burning fields in Wennington, a village on the eastern outskirts of London.

Sales of fans at one retailer, Asda, increased by 1,300%. Electric fans cooled the traditional mounted troops of the Household Cavalry as they stood guard in central London in heavy ceremonial uniforms. The length of the changing of the guard ceremony at Buckingham Palace was shortened. The capital’s Hyde Park, normally busy with walkers, was eerily quiet — except for the long lines to take a dip in the Serpentine lake.

“I’m going to my office because it is nice and cool,” said geologist Tom Elliott, 31, after taking a swim. “I’m cycling around instead of taking the Tube.’’

Ever the stalwart, Queen Elizabeth II carried on working. The 96-year-old monarch held a virtual audience with new U.S. ambassador Jane Hartley from the safety of Windsor Castle.

A huge chunk of England, from London in the south to Manchester and Leeds in the north, remained under the country’s first “red” warning for extreme heat Tuesday, meaning there is danger of death even for healthy people.

Such dangers could be seen in Britain and across Europe. At least six people were reported to have drowned while trying to cool off in rivers, lakes and reservoirs across the U.K. In Spain and neighboring Portugal, hundreds of heat-related deaths have been reported in the heat wave.

Climate experts warn that global warming has increased the frequency of extreme weather events, with studies showing that the likelihood of temperatures in the U.K. reaching 40 C (104 F) is now 10 times higher than in the pre-industrial era.

The head of the U.N. weather agency expressed hope that the heat gripping Europe would serve as a “wake-up call” for governments to do more on climate change. Other scientists used the milestone moment to underscore that it was time to act.

“While still rare, 40C is now a reality of British summers,” said Friederike Otto, Senior Lecturer in Climate Science at Imperial College London’s Grantham Institute for Climate Change. “Whether it will become a very common occurrence or remains relatively infrequent is in our hands and is determined by when and at what global mean temperature we reach net zero.”

Extreme heat broiled other parts of Europe, too. In Paris, the thermometer in the French capital’s oldest weather station – opened in 1873 – topped 40 C (104 F) for just the third time. The 40.5 C (104.9 F) measured there by weather service Meteo-France on Tuesday was the station’s second-highest reading ever, topped only by a blistering 42.6 C (108.7 F) in July 2019.

Drought and heat waves tied to climate change have also made wildfires more common and harder to fight.

In the Gironde region of southwestern France, ferocious wildfires continued to spread through tinder-dry pines forests, frustrating firefighting efforts by more than 2,000 firefighters and water-bombing planes.

Tens of thousands of people have been evacuated from homes and summer vacation spots since the fires broke out July 12, Gironde authorities said.

A smaller third fire broke out late Monday in the Medoc wine region north of Bordeaux, further taxing resources. Five camping sites went up in flames in the Atlantic coast beach zone where blazes raged around the Arcachon maritime basin famous for its oysters and resorts.

In Greece, a large forest fire broke out northeast of Athens, fanned by high winds. Fire Service officials said nine firefighting aircraft and four helicopters were deployed to try to stop the flames from reaching inhabited areas on the slopes of Mount Penteli, some 25 kilometers (16 miles) northeast of the capital. Smoke from the fire blanketed part of the city’s skyline.

But weather forecasts offered some consolation, with temperatures expected to ease along the Atlantic seaboard Tuesday and the possibility of rains rolling in late in the day.

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Associated Press writers Sylvia Hui and Jo Kearney in London, John Leicester in Le Pecq, France, Mike Corder in The Hague, Netherlands, and Jamey Keaten in Geneva contributed to this story.

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Follow AP’s climate coverage at https://apnews.com/hub/climate-and-environment.

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