Climate change is warming the Arctic tundra about four times faster than the rest of the planet. Now, a study suggests that rising temperatures will spur underground microbes there to produce more carbon dioxide — potentially creating a feedback loop that worsens climate change.

The tundra is “a sleepy biome,” says Sybryn Maes, an environmental scientist at Umeå University in Sweden. This ecosystem is populated by small shrubs, grasses and lichen growing in cold soils rich with stored organic carbon. Scientists have long suspected that warming will wake this sleeping giant, prompting soil microbes to release more of the greenhouse gas CO2 (SN: 8/11/22). But it’s been difficult to demonstrate in field studies.

Maes’ team included about 70 scientists performing measurements in 28 tundra regions across the planet’s Arctic and alpine zones.

During the summer growing season, the researchers placed clear, open-topped plastic chambers, each about a meter in diameter, over patches of tundra. These chambers let in light and precipitation but blocked the wind, warming the air inside by an average of 1.4 degrees Celsius. The researchers monitored how much CO2 microbes in the soil released into the air, a process called respiration, and compared that data with measurements from nearby exposed patches.

The study, published online April 17 in Nature, found that the 1.4 degree C temperature increase caused an average 30 percent increase in CO2 respiration across the experimental sites compared with the exposed sites. Some of the studies the team compiled lasted only one year, but the longest provided measurements from 25 growing seasons, showing that these effects persist over time.

Though it’s clear that higher temperatures boost CO2 respiration on average, there’s a lot of variability between field sites, Maes says. For instance, the CO2 ramp-up is particularly pronounced in nitrogen-poor soil. As soils warm, plants become more active, and so do their symbiotic microbes, which support the plants by scavenging for nitrogen. The microbes’ heightened activity also means they produce more CO2.

The findings provide the strongest evidence yet that warmer temperatures will increase microbial activity, releasing more CO2, says environmental microbiologist Nicholas Bouskill of Lawrence Berkeley National Laboratory in California. Previous studies, including Bouskill’s own, were much smaller and came to contradictory conclusions.

The long-term question, Bouskill says, is: “Will these areas become carbon sources, or will they remain carbon sinks?”

NASA estimates that the Arctic permafrost stores 1,700 billion metric tons of carbon. Recent studies find that by the year 2100, degrading permafrost could release anywhere from 22 billion to 524 billion metric tons of carbon, depending on the rate of warming.

Given the expected increase in CO2 emissions from microbes and their potential to contribute to further global warming, “you could say this is a doom scenario,” Maes says. But she notes that the study’s results do not mean the tundra’s overall carbon emissions will inevitably skyrocket — other processes may counteract this effect. For example, plants could ramp up their photosynthetic activity, taking up more CO2. And these studies don’t factor in what happens during other times of year.

Incorporating data that captures the nuance of what’s happening in the Arctic — such as the link between nitrogen-poor soil and microbial respiration — may help improve predictions about the tundra’s response to climate change and how that will, in turn, influence Earth’s climate. “We need to represent how nutrients are cycling in order to get the carbon right,” Bouskill says.

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If billionaires actually cared about saving the planet, they’d pool their vast wealth and buy everyone a heat pump. Instead of burning planet-warming fossil fuels, these appliances extract warmth from even freezing outdoor air and transfer it into a building, thanks to neat tricks of physics. In the summer, they reverse to act like an air-conditioning unit. One recent study found that if everyone in the United States got a heat pump, it’d slash emissions in the building sector by 36 to 64 percent, and cut overall national emissions by 5 to 9 percent. (Because they’re fully electric, heat pumps run on a grid increasingly loaded with renewable energy.)

Not that billionaires would ever have the altruism or desire to buy us all heat pumps—megayachts aren’t going to buy themselves, after all. But if they did, there’d be one critical hurdle they’d run into—the one thing that’s holding heat pumps back from their full potential more generally: There aren’t enough trained workers yet to install them.

“No one talks about supply chain constraints anymore. What is now the bottleneck is actually the installer,” says Philipp Krinner, CEO and cofounder of Arch, a platform that helps HVAC (heating, ventilation, and air-conditioning) companies manage customers. “In the winter and in the summer—in the peak seasons—when most people actually want to install a system, it’s actually still a contractor-constrained market.”

The result is classic “greenflation,” a temporary rise in the costs associated with decarbonization due to market constraints, says climate economist Gernot Wagner of the Columbia Business School in New York. “Yes, there is a shortage of qualified contractors,” he says. But it’s a good problem to have, he argues, and “one where there’s an obvious solution” on the road to decarbonizing our civilization. It’ll be costly to train more workers in the green economy, but that’ll end up paying huge dividends.

“Electricians get talked about a lot, and used as sort of an avatar for all of the jobs that are going to be needed to install heat pumps and decarbonize the economy,” says Alexandria Herr, senior research associate at Rewiring America, a nonprofit that promotes electrification. “But it’s not just electricians—it’s actually a whole range of different jobs across the construction trades.” Qualified workers are needed to determine what kind of heat pump a home or business requires, to install the things, and then to service them. A heat pump is fundamentally different from a gas-fired furnace, and it requires fundamentally different training.

That would include workers specializing in “weatherization”—better insulating homes so heat pumps get even more efficient. And we’ll need specialists to retrofit the grid so it can smoothly transition to handling the ebb and flow of renewable energy, which is what makes heat pumps so climate-friendly. And we’ll need workers in manufacturing to produce the units themselves.

And we need these people ASAP. Heat pump sales are already outpacing the sale of gas furnaces in the US. The Inflation Reduction Act of 2022 provides thousands of dollars in tax rebates and credits for households to both switch to a heat pump and pay for the electrical upgrades that may be required to run the appliances. Last year, the Biden administration announced $169 million to supercharge the domestic manufacturing of whole heat pumps and their individual components. And in February, nine states signed a memorandum of understanding to accelerate the adoption of heat pumps.

So the demand is there, as is growing support from the federal and state governments. What’s lagging is the workforce—at least temporarily. And the US is nowhere near alone: Wherever heat pump adoption is growing, more workers need to train up to meet demand. “If you look at a place like, say, Finland, where pretty much all your heating systems are heat pumps, this is not really an issue anymore,” says Jan Rosenow, who studies electrification at the Regulatory Assistance Project, a policy NGO for the energy community. “If you wanted to buy an electric car 10 years ago, it was quite difficult, wasn’t it? Now, you can go to any showroom and you can find them. I think the same is going to be the case with heat pumps. It’s already the case with heat pumps in more mature markets.”

In the US, though, we don’t have some sort of giant, national program to quickly get more people trained in HVAC. “It would just make sense that there would be this path to learn more about heat pumps, and then there would be a whole armed force to go out and install these things,” says Ed Janowiak, manager of HVAC and refrigeration design education at the nonprofit Air Conditioning Contractors of America. “There is such an opportunity right now for people to get in on the ground level. It should not take them very long to make a decent wage at it. And I still sit here at times with my palms in the air as to why it isn’t just automatically happening.”

There isn’t one official pathway in the US for HVAC workers, but several. Trade schools and community colleges provide HVAC training. Trade unions offer apprenticeships, and many HVAC companies run their own training programs to get people into the trade. “The most successful companies right now that are finding these people to install, they’re not necessarily hiring people that are already in the field,” says Janowiak. “But if you look at the number of technicians that go through those programs nationally, versus the demand, it’s just not there. So we need a lot more people.”

For veteran HVAC workers already trained in fossil-fuel systems, like installing gas furnaces, heat pump manufacturers provide their own training to install their products, which is of course in their interest. HVAC companies also do their own heat pump training for established workers, which usually takes two days. If a home has ducting, a heat pump will work similarly to a traditional AC unit, so the installation is nearly identical.

But all these workers don’t just have to be trained, but trained well, lest they inadvertently turn customers off of the energy-efficient appliances just as the heat pump revolution is getting going. If the size of the heat pump doesn’t suit the size of the home, or the ducting within, it won’t be as efficient. If you don’t have ducting, a contractor might recommend a simpler ductless heat pump, which is set into an outside-facing wall. “My biggest hope is that those people who do end up installing these, do get trained wisely,” says Janowiak, “and they do install pieces of equipment that work the way we want them to.”

An added challenge is that the US needs a robust network of training programs all across the country: You can’t have someone remotely install a heat pump, which means we’ll need not just an army of trained workers, but a properly distributed one.

Over in the UK, the energy supplier Octopus Energy has even built two full-scale model houses for workers to train in, one representing modern housing stock and the other older brick stock from the 1960s or 1970s. The company uses the homes to train workers new to the heating industry—it directly employs these folks during the education process, so they get paid—but also to reskill veterans who’ve been installing fossil-fuel systems. “Actually, we don’t really have a skill shortage at all—we just have a set of people that are installing the wrong product,” says John Szymik, CEO of Octopus Energy Services. “We built those [model homes] in order to show people how you’d optimize a rollout for the mass market.”

Working in an older UK home, for instance, technicians need to account for much worse insulation than in a modern home. The size of the home matters, as does the number of occupants and kinds of windows. All that data goes into a calculation that Octopus uses to determine the size of the heat pump. “Those homes are really, really helpful for our surveyors’ understanding of how to go around and measure up,” says Szymik. Then during a heat pump installation in the real world, a newly trained worker would join a crew of more experienced technicians. “What you get there is the opportunity to blend your people that have been working on this for a while, have more experience, with the people that are coming into it fresh with slightly less experience.”

A new breed of heat pumps is also making it possible for some people to skip hiring a trained installer entirely. The New York City Housing Authority, for instance, is deploying units that slip over a window sill and plug into the wall. One of the companies making that type, Gradient, says that a resident can install one in less than an hour, in contrast to a team of technicians installing a traditional heat pump in about a day. For an apartment dweller without ducting, this might be an ideal option that skips the extra step of having a contractor analyze the space and deploy a more complicated system.

The other option is to just hope the heat pump revolution unfolds smoothly on its own: Maybe the HVAC industry will meet that demand with American-made devices installed by newly trained workers. Finland, after all, eventually found its way. “There may well be the need for large-scale retraining programs,” says Wagner. “Maybe I’m too much of a business school economist—please excuse me of that—but frankly, one answer is to simply get out of the way and let the market do its thing.”

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This article breaks down the common causes of strokes, using straightforward language and supporting evidence, making it easier for everyone to understand how these critical events happen and how they might be prevented.

A stroke occurs when the blood supply to part of the brain is interrupted or reduced, preventing brain tissue from getting oxygen and nutrients.

Brain cells begin to die in minutes. Strokes can be classified into two main types: ischemic and hemorrhagic.

Ischemic strokes, which are more common, occur when a blood clot blocks or narrows an artery leading to the brain. Hemorrhagic strokes happen when an artery in the brain bursts. Both result in parts of the brain not functioning correctly.

Several factors and conditions can increase your risk of having a stroke, and understanding these can help in prevention efforts. Here are some of the most well-documented causes:

High blood pressure (hypertension): This is the leading cause of stroke and the most significant controllable risk factor. High blood pressure puts a strain on blood vessels throughout the body, including those leading to the brain, which can lead to strokes over time.

According to the American Heart Association, managing blood pressure is one of the most effective ways to reduce your stroke risk.

Tobacco use: Smoking or even exposure to secondhand smoke can increase stroke risk. Smoking promotes clot formation, thickens blood, and increases the amount of plaque buildup in arteries, as reported by numerous studies. Quitting smoking can significantly reduce the risk of stroke.

Heart disease: Common heart disorders like coronary artery disease, valve defects, irregular heartbeats (like atrial fibrillation), and enlarged heart chambers can increase stroke risk.

Atrial fibrillation is particularly noteworthy because it can cause blood clots to form in the heart and then travel to the brain, leading to ischemic stroke.

Diabetes: People with diabetes are at higher risk because diabetes is associated with conditions that damage the blood vessels, making clots more likely. Managing diabetes is crucial to reducing the risk of stroke, as well as other complications like heart disease.

Diet and exercise: Diets high in saturated fats, trans fats, and cholesterol can raise blood cholesterol levels, while high salt (sodium) intake can contribute to increased blood pressure. Both of these factors can increase stroke risk.

On the other hand, a diet rich in fruits and vegetables and regular physical activity can lower stroke risk by improving overall cardiovascular health.

Obesity: Being overweight can increase the likelihood of high blood pressure, heart disease, and diabetes, all of which are risk factors for stroke. Weight loss through diet and exercise can lower these risks significantly.

Age, family history, and gender: These factors are not controllable but are important to recognize. Your chance of having a stroke increases as you get older, especially after the age of 55.

Men have a higher risk of stroke at a younger age, but more women have strokes at an older age and are more likely to die from strokes than men. Family history of stroke also increases your risk.

Strokes are complex events influenced by a variety of lifestyle factors, medical conditions, and genetic predispositions.

However, up to 80% of strokes can be prevented through lifestyle changes such as controlling high blood pressure, quitting smoking, and maintaining a healthy weight through diet and exercise.

Recognizing the common causes of stroke not only aids in prevention but also empowers individuals to make informed decisions about their health. Knowing these factors can help you and your loved ones take action early to prevent this life-threatening condition.

If you care about stroke, please read studies that diets high in flavonoids could help reduce stroke risk, and MIND diet could slow down cognitive decline after stroke.

For more information about nutrition, please see recent studies about antioxidants that could help reduce the risk of dementia, and tea and coffee may help lower your risk of stroke, dementia.

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Monday, 6 May

• Who: SpaceX
• What: Falcon 9
• When: 3:34 p.m. - 8:05 p.m. UTC
• Where: Florida, US
• Why: SpaceX will launch a Falcon 9 carrying 23 Starlink satellites to orbit. This batch is known as Starlink Group 6-56, this identifier can be used on apps like ISS Detector to try and spot them flying through the night sky. For anyone that doesn’t know, SpaceX’s Starlink satellites beam internet down to the Earth and even provide internet in remote areas not served by traditional broadband.

Tuesday, 7 May

• Who: United Launch Alliance
• What: Atlas V
• When: 2:34 a.m. UTC
• Where: Florida, US
• Why: United Launch Alliance will launch an Atlas V rocket carrying the CST-100 Starliner spacecraft carrying a crew to the International Space Station as part of a test flight. The astronauts will include Barry Wilmore and Sunita Williams from NASA. This mission is being carried out as part of NASA’s commercial crew program.

• Who: China
• What: Long March 6C
• When: 3:20 a.m. UTC
• Where: Taiyuan, China
• Why: China will launch a Long March 6C for the first time carrying the Neptune 1 Synthetic Aperture Radar satellite for Ningbo Zhihui Space Technology Co., Ltd. This satellite is just the first satellite in a constellation that will eventually be 36 satellites strong.

• Who: SpaceX
• What: Falcon 9
• When: 10:09 a.m. UTC
• Where: Florida, US
• Why: SpaceX will launch a Falcon 9 carrying 23 Starlink satellites. This group is Starlink Group 6-57. They will join the huge Starlink constellation to beam the internet down to Earth. Like most other Starlink missions, we should see the first stage of the Falcon 9 perform a landing.

Wednesday, 8 May

• Who: SpaceX
• What: Falcon 9
• When: 2:48 a.m. - 7:18 a.m. UTC
• Where: California, US
• Why: This batch of Starlink satellites is Group 8-2, they will be placed in a low Earth orbit before being switched on. Interestingly, this group of about 22 satellites could feature six direct-to-cell Starlink satellites - these are relatively new with the first satellites of this type being sent up just several months ago.

Thursday, 9 May

• Who: China
• What: Long March 3B/E
• When: 1:50 a.m. UTC
• Where: Xichang, China
• Why: China will use a Long March 3B or 3E to launch two BeiDou navigation satellites for the government. The BeiDou satellites operate in a medium Earth orbit (MEO) which is further out than a low Earth orbit which Starlink operates in. Most modern smartphones support BeiDou satellites to help improve location accuracy on Google Maps.

Recap

• The first launch we got last week was the SpaceX Starlink 159 mission. 23 Starlink satellites were launched, known as Starlink Group 6-54, and then the first stage of the rocket performed a landing.

• The second launch was also a Falcon 9 but this time it was carrying two WorldView Legion satellites for Maxar. These satellites are the first two of six planned WorldView Legion satellites.

• Next up, SpaceX has 23 more Starlink satellites to launch, known as Starlink 6-55. The first stage of the Falcon 9 also performed a landing.

• Finally, China launched its Chang’e-6 mission to the moon atop a Long March 5 Y8. The aim of this lunar mission is to collect samples from the far side of the moon and bring them back to Earth for examination.

That’s it for this week, check in next time.

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📷 The tree , which was at least 200 years old, appeared to have been sawed at the base with a chainsaw. Photograph: Owen Humphreys/PA

Police have charged two men in their 30s over the felling of the Sycamore Gap tree last September.

Daniel Michael Graham, 38, and Adam Carruthers, 31, both from Cumbria, have been charged with criminal damage to the tree and to a neighboring part of Hadrian’s Wall, which was affected when the tree fell.

They are due to appear at Newcastle magistrates court on 15 May.

The men were arrested in October in connection with the incident and had been on bail since that date, police said.

Det Ch Insp Rebecca Fenney, the senior investigation officer in the case, said: “There has been an ongoing investigation since the Sycamore Gap tree was cut down.

“As a result of those inquiries, two men have now been charged.

“We recognise the strength of feeling in the local community and further afield the felling has caused, however we would remind people to avoid speculation, including online, which could impact the ongoing case.”

Residents awoke on 28 September last year to find the iconic tree had been felled overnight.

The tree, which was at least 200 years old, appeared to have been saw at the base of the trunk with a chainsaw, having previously stood in a small picturesque valley in Northumberland national park in the north of England.

The world-famous tree, voted English tree of the year in a Woodland Trust competition in 2016 and featured in the 1991 film Robin Hood: Prince of Thieves, was mourned by locals and people all over the globe.

A candlelit vigil was organised and visitors flocked to the site to say goodbye to the landmark and the National Trust said it had been “amazed and inspired” by offers of help and good wishes from the public.

The organisation collected seeds and cuttings, some of which it was able to propagate.

Source : https://www.theguardian.com/uk-news/2024/apr/30/two-men-charged-over-felling-of-sycamore-gap-tree

"Opening the Supercharger network will definitely add to Tesla's top-line revenue," said Sam Abuelsamid, principal analyst of transportation and mobility at Guidehouse Insights. "Whether it is profitable revenue is hard to say for sure; the prices they charge aren't cheap and can be upward of $0.50/kWh ,so presumably, they are at least breaking even, if not profitable, on variable cost of electricity."

 

More than just a profit line, "there is another crucial reason for opening the Supercharger network, NEVI," said Abuelsamid, referring to the $5 billion for high-speed EV charging allocated by the Biden administration. "Tesla has always thrived on subsidies. To be eligible for NEVI funding that pays for much of the cost of installing DC fast charging, the chargers must be open to all users, not just a specific brand. That’s exactly why Rivian is opening up its adventure charging," Abuelsamid told me.

 

There's a chance that scaling back on charging won't hurt Tesla that much. "EV charging in the US remains a growth field, but with the rest of the industry pivoting to Tesla's own charging standard, why does Tesla’s charging team need to be so big, or even exist?" Jominy asked. "I'm not positive of the reciprocity agreements in adopting NACS, but if you're an automaker like Rivian with its own fledging charging network that has gained access to the Supercharger network, your owners now have more high-speed charging access than Tesla owners. How does Tesla win by continuing to play in that game?

 

"Charging is a massive capital investment. From here, future investments are about filling in white space on the charging map," Jominy said. "It's like most major cities have an Ikea. Does it take a massive team to determine what cities next need one or if a large city needs a second? Those are innocuous decisions relative to the crucial ones during the initial rollout strategy. Each incremental investment in Superchargers from here produces marginal gains at best, and where to place future bets becomes increasingly obvious by looking at a map or owner statistics."

 

"I don't know if it's something where Elon just doesn't care about charging anymore. Like, he can just say, 'whatever' and take the hit on it and just miss out on future subsidies," author Ed Niedermeyer said. "I think that's a risk. The weird thing about all this is why is he not spinning this out? Why isn't he selling this?"

Should Musk stay in charge?

A question I'm increasingly seeing in Ars comments and on social media is whether Tesla could ever be a normal car company, perhaps if it were run by someone more... normal.

 

"It's not clear that another person could run Tesla, at least not in the manner that Mr. Musk does," said Jominy. "Tesla could assimilate into the automotive sphere with another CEO, have a fully developed product roadmap, but the margins, growth, and therefore stock price, of an automaker are much lower than Tesla's. If another CEO is instilled, then the latest bet on a pivot to AI will have failed."

 

Abuelsamid, on the other hand, thinks it's long past time for Tesla's board of directors to show Musk the door. "In retrospect, that might not have been the best thing for the company in the late 2010s, simply because the key to the company’s survival was the ability to raise free capital seemingly by selling more shares whenever it was running out of money," he said. "That might not have been possible in Elon's absence because the people buying and pumping the shares were part of a cult of personality buying into Elon’s mostly fanciful narratives about solar roofs and autonomy."

 

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Have you heard? The hybrids are coming. As sales growth falters for electric vehicles, particularly in the United States, automakers have started to turn their gaze toward the EV’s less-charged-up cousins.

Some may see hybrids as less sexy, or less worthy, than full-electric cars. But global government emissions rules, along with hybrids’ reputation as an EV “gateway drug,” have made these cars an attractive stop on the electrified vehicle roadmap. Expect to see way more of them for sale in the coming years.

Alas, the world of hybrids is confusing. Some plug in for power; some don’t. Some can avoid gas fuel altogether; some won’t operate without it. As a result, some come with big emissions (and gas money) savings. Frustratingly, some commentators call all hybrids, well, “hybrids,” without specifying which technology they’re using.

Here’s WIRED’s guide to everything you need to know about hybrid cars.

Table of Contents

• So, What’s a Hybrid?
• What's a Hybrid Going to Cost Me?
• What Hybrid Should I Choose?
• Running Costs
• Trade-In Value

The electric-curious car buyer will want to know a few key terms—and acronyms. Your standard gas-powered car has an internal combustion engine, so it’s sometimes called an ICE vehicle. These vehicles tend to produce the most emissions. On the other side of the spectrum are battery-electric cars, or EVs or BEVs, which are powered by a battery connected to an electric motor. (Confusingly, some data sources group plug-in hybrids under the larger EV umbrella.) BEVs must be plugged in to charge up. The climate friendliness of these depends, to a degree, on what’s inside their batteries and how your local electricity grid is powered, but plenty of research has confirmed that EVs always produce fewer lifetime emissions than ICE vehicles.

Hybrids are more complicated but can be broken into three big categories: mild hybrids, hybrids, and plug-in hybrids.

Mild hybrids use larger-than-standard electrical generators (alternators) to give some extra assist to a gas-powered engine. This setup allows the gas engine to turn off, for example, while the car is coasting or when it’s at a stop light. “They offer a bit of fuel economy gain,” says Will Kaufman, a senior editor at Edmunds, an automotive publication—somewhere in the 15 to 10 percent range. But generally, he says, automakers aren’t focusing on this tech anymore.

Hybrids, or HEVs, have both gas engines and electric motors, which get their power from batteries. No plugs here: A hybrid’s electric motor is charged by its gas engine and by regenerative braking, which recovers the energy used when a car is stopping. Generally, that electric motor is in charge when the car is traveling short distances and needs less power—for example, when it’s coasting on the highway or in stop-and-go traffic. The gas engine performs the more energy-intensive driving tasks, including accelerating and powering up hills.

Plug-in hybrids, PHEVs, have—you guessed it—plugs. They have both electric motors and gas engines. PHEVs get some of their power through chargers and outlets, even the standard 120-volt wall plug found in most homes. Note, however, that many PHEVs on the market today can’t get charge from the public “fast chargers” increasingly installed along highways in the US, because they don’t come with the connector that would allow them to plug in. (Exceptions include specific models of the Mitsubishi Outlander PHEV and the Mercedes-Benz GLC 350e.)

Plug-in hybrids have smaller batteries than their all-electric counterparts, only good for 20 to 50 miles of travel, compared to more than 200 in all-electric cars. Like BEVs, PHEVs get fewer battery-powered miles in the cold. Once the power in the battery runs out, PHEVs drive like hybrids and burn gas. As a result, the emissions output of PHEVs depends on how their owners operate them—whether they’re traveling distances mostly covered by the battery and whether they’re diligent about keeping them charged.

Right now, cars are generally more expensive the more they depend on a battery to go. Here’s a handy chart, using data from the automotive research company Edmunds:

In the US, both BEVs and PHEVs are eligible for federal and sometimes local tax credits. Specific makes and models of plug-ins, including the 2022 through 2024 model years Chrysler Pacifica Hybrid PHEV and the 2023 and 2024 Audi Q5 PHEV, are eligible for at least some tax credits from the US federal government, though the amount depends on where certain components of the car are made and how much it costs, and so are subject to change.

In Europe, France, Spain, and the UK all have subsidies for some kinds of hybrid buyers but have cut back on their programs as the vehicles have become more popular.

Check with your local authorities to see what applies—and whether they’ll help bring down the price.

That (☝️) pricing issue means that some car buyers shy away from battery-electric cars. BEVs also aren’t a great choice right now for those who regularly drive very long distances, or who don’t have access to a charger at home, or who only have one car for the household. A more robust public charging network is coming to the US, but while the country waits, those accustomed to the frequency of gas stations might hesitate before going all-electric.

This is where the plug-in hybrids come in. “They’re an opportunity to dip your toe into electrification,” says Kaufman, the Edmunds editor. The ideal plug-in hybrid driver has a shorter commute, in the 40-mile round-trip range. It’s also a great option for people who want to go electric but only have one car. “You can do any road trip you want,” says Kaufman. “It’s not like an EV, where you have to plan your route around charging stops.”

But to really take advantage of plug-in hybrids, drivers should have access to at-home charging. A home charger will give owners the highest likelihood of using mostly electric power while they’re traveling—and putting out fewer emissions.

Consumer Reports has found that, in general, plug-in hybrids are less expensive to fuel than their gas-powered or even hybrid counterparts. But the final tally depends on how a plug-in driver uses their car. If they never plug it in to charge it, they won’t get much bang for their buck. CR’s tests with one PHEV, a Hyundai Tucson, found that the vehicle gets lower gas mileage than its hybrid counterpart if it’s never charged, leading to an annual additional gas cost of $150 or more compared to the hybrid version.

One major complaint about electric vehicles is that they’re not holding their value as the years go by. (Tesla’s aggressive price cutting has not helped.) The vehicle research firm iSeeCars.com found last month that while used vehicle prices have fallen 3.6 percent since last year, used EV prices have fallen 31.8 percent.

The issue isn’t quite as pronounced with plug-in hybrids. iSeeCars.com finds that some of the most popular plug-in hybrids, including the Toyota Prius and the Toyota Prius Prime, hold nearly 70 percent of their value over five years. Still, in general, hybrids grouped together as a class are not holding value as much as traditional gas-powered vehicles—something to consider before you hit the dealership lot.

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The University of Tokyo Atacama Observatory (TAO) officially opened on Tuesday after 26 years of planning and construction. Sitting 18,500 feet high on Mount Chajnantor in the Atacama Desert in Chile, the 6.5-meter optical-infrared TAO telescope is now the highest in the world.

 

TAO replaces a smaller version of itself called MiniTAO, which held the highest telescope distinction before it. It beats the Chacaltaya Observatory, owned by the University of Madrid and sitting 17,191 feet on Mount Chacaltaya in Bolivia.

 

The next three record holders in the top five are also in Chile’s Atacama desert: the James Ax Observatory (17,100 feet); the Atacama Cosmology Telescope (17,030 feet); and the Llano de Chajnantor Observatory (sources vary; about 16,700 feet). Many of the world’s major observatories are built in the high-altitude, northeastern area of Chile, near Bolivia, because of its clear skies. The country’s tax exemptions for such projects help, too.

 

Being so high up means far less moisture in the air; TAO can observe “almost the entire range of near-infrared wavelengths,” including mid-infrared. No other earthbound telescope can do that, Phys.org notes. The University of Tokyo writes that such terrestrial observatories are capable of taking higher-resolution shots of space, thanks to their larger apertures, than their space-based counterparts. The telescope will be used to learn about “the birth of galaxies and the origin of planets” starting in 2025, according to the University of Tokyo’s announcement.

 

A diagram of the 6.5-meter diameter telescope.

Image: University of Tokyo

 

There’s a thought it could also improve on observations from the nearby ALMA telescope by viewing the same objects in different wavelengths to give researchers new insights.

 

TAO’s primary mirror.

Image: University of Tokyo

 

The benefits of TAO sitting at such an extreme altitude come at a cost, however, as humans are pretty ill-suited for life that high up. Yuzuru Yoshii, the principal investigator who started the project in 1998, said that builders working on the telescope needed medical checkups and had to regularly inhale oxygen while they worked.

 

As Phys.org notes, even the researchers working inside will need to take precautions to stay healthy in the face of altitude sickness. The team plans to eventually operate the telescope remotely from a lower base facility to avoid such issues.

 

Besides ALMA, TAO joins other Atacama-based observatories like the European Extremely Large Telescope on the top of Cerro Armazones and the European Very Large Telescope that sits atop Cerro Paranal.

 

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For over a year, global ocean temperatures have been consistently shattering records, shocking scientists. Now hurricane watchers are getting even more worried, given that ocean heat is what fuels the biggest, most destructive cyclones. Researchers at the University of Arizona just predicted an extremely active North Atlantic season—which runs from June 1 to the end of November—with an estimated 11 hurricanes, five of them being major (meaning Category 3 or higher, with sustained wind speeds of at least 111 miles per hour). That would dwarf the 2023 season—itself the fourth-most-active season on record—which saw seven hurricanes, three of which intensified into major ones.

“Part of the reason is very warm ocean surface temperatures in the tropical Atlantic Ocean,” says Xubin Zeng, director of the Climate Dynamics and Hydrometeorology Center at the University of Arizona. The other reason is that the Pacific Ocean is transitioning from a warm El Niño, which discourages the formation of Atlantic hurricanes, into cold La Niña, which encourages them. “So those two factors together give us a very active hurricane season prediction for this year.”

As a tropical cyclone grows, scientists measure sustained wind speeds to get an idea of how it’s intensifying. (“Tropical cyclone” is the general term for these storms. The ones that hit the coasts of the US are known as hurricanes.) When the speeds increase by 30 knots (35 miles per hour) or more in 24 hours, that’s considered “rapid intensification.” Last year’s Hurricane Lee, for instance, grew from 70 knots to 116 knots over just 12 hours. Previous research has found a huge increase in this sort of rapid intensification near coastlines since 1980.

And it’ll only get worse from here. A study from another group of scientists, published today in Earth’s Future, finds that across the planet, hurricanes have been intensifying faster and faster. It looked at hurricane behavior near coasts, as opposed to when they’re traveling across the open ocean, and measured intensification generally instead of rapid intensification specifically.

The study found that globally in the last four decades, the tropical cyclone intensification rate has grown by 3 knots per 24 hours. Put another way: We can expect a hurricane today to intensify by 3 extra knots over the course of a day, on average. Between 1979 and 2000, the average rate of intensification increased by 0.37 knots every six hours of a hurricane’s lifespan, rising to 1.15 knots every six hours in the period between 2000 and 2020.

The authors warn that climate change is creating the conditions for plenty more coastal intensification going forward. That, in turn, is making hurricanes more dangerous than ever, as the storm can suddenly intensify close to shore into something fiercer than what emergency agencies were preparing for. “This increase in intensification near the coast is supported by changes in the environment,” says Pacific Northwest National Laboratory climate scientist Karthik Balaguru, lead author of the paper in the journal Earth’s Future. “The projected changes also show increasing intensification of tropical cyclones in a future climate.”

Three main factors converge to intensify hurricanes. The first is that as the world in general warms, so too do the oceans. Water evaporating off the surface rises, releasing heat that fuels the developing hurricane. The warmer a patch of ocean water is, the more energy a cyclone has to exploit. If a hurricane like Lee forms off the coast of Africa, it’s got a lot of Atlantic ocean to feed on as it moves toward the East Coast of the United States. As we approach this year’s hurricane season, tropical Atlantic temperatures remain very high.

The second factor is humidity. As the atmosphere warms, it can hold more water vapor, so some parts of the world are getting more humid. Hurricanes love that, as drier air can lead to cooling and downdrafts that counteract the updrafts that drive the storm. “So long as it remains moist, the storm can strengthen, or maintain its intensity,” says Balaguru. “However, once the core enters into a dry environment or becomes less moist, then the storm will start weakening.”

And lastly, hurricanes hate wind shear, or winds of different speeds and directions at different altitudes. (Think of it like layers of a cake, only made of air.) Instead, cyclones like a stable atmosphere, which allows their winds to get swirling and intensifying. Wind shear can also inject drier air from outside the storm into the core of the hurricane, further weakening it. As the world warms, wind shear is decreasing along the US East Coast and East and South Asia, providing the ideal atmospheric conditions for cyclones to form and intensify. “Under climate change, the upper troposphere is expected to warm up at a higher pace than the surface,” says Balaguru. “This can enhance the stability of the atmosphere and also weaken the circulation in the tropics.”

Nearer term, La Niña conditions in the Pacific could help form and intensify hurricanes this summer. Even though La Niña’s in a different ocean, it tends to suppress winds over the Atlantic, meaning there’s less of the wind shear that hurricanes hate. Hence the University of Arizona’s prediction for an extremely active hurricane season, combined with very high sea surface temperatures in the Atlantic to fuel the storms. By contrast, last year’s El Niño created wind conditions in the Atlantic that discouraged the formation of cyclones.

Even then, Hurricane Lee developed into a monster storm last September. A week before that, Hurricane Idalia rapidly intensified just before slamming into Florida. That sort of intensification close to shore is extraordinarily dangerous. “When the storm is very close to the coast—let's say it's a day or two out—if it then suddenly intensifies rapidly, then it can throw you off guard in terms of preparations,” says Balaguru. A town may have planned its evacuations expecting winds of 100 mph, and suddenly it’s more like 130 mph.

Unfortunately, Balaguru’s new study finds that climatic conditions, particularly near the coast, are becoming more conducive for storm intensification. It’s up to teams like Zeng’s at the University of Arizona to further hone their forecasts to manage that growing risk to coastal populations. “For scientists, seasonal forecasting is a reality check of our understanding,” says Zeng. “We have done pretty well over the past few years, and it's going to give us more confidence.”

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We recently reported on the months-long communication issue of the iconic Voyager 1, which was sending erroneous data that NASA engineers were unable to decipher. To their delight, this glitch was ultimately fixed, NASA announced on April 22.

However, as the agency revealed late last week, on the very next day, April 23, another spacecraft encountered difficulties that knocked it out of operation. This time, it was the iconic Hubble Space Telescope that ran into trouble with gyros and entered safe mode, placing its science instruments in a stable condition and awaiting commands from NASA.

It’s not the first time that the telescope’s gyroscopes have failed. In fact, they are the least reliable part of the spacecraft, and this is just another episode in the Spinnin’ Wheels docuseries that could one day be streamed on NASA TV.

One of the holy grails of astronomy, launched in 1990, is serving on low Earth orbit well beyond its originally planned lifespan of 15 years. All that thanks to the Space Shuttle’s ability to execute servicing missions to the precious spacecraft.

The fifth and last servicing mission to Hubble was conducted in 2009. As part of the mission, all six gyroscopes onboard Hubble were replaced. Three of them – already inoperable by now – were of the old design, while another three were redesigned for improved reliability.

One of these “new” gyros, however, has been problematic since the very beginning, and this is not the first time it has caused a headache for NASA engineers. The last time it stopped the Hubble from scientific operations was in November. The agency is currently trying to figure out a solution for the latest trouble.

It is important to note, that in an ideal scenario, Hubble is operating with three working gyroscopes, however, it can be re-configured to work with only one gyro (although with some limitations to its observation abilities). Therefore, the engineers remain optimistic, and once fixed, they expect the telescope to continue making groundbreaking discoveries throughout this decade and possibly into the next.

Hubble Space Telescope made over a million observations in its 34 years of existence, and many of them provided us with unbelievable imagery of the universe. You can watch Hubble’s highlights on NASA’s website, and if you are interested in the latest groundbreaking tech flying to space, don’t forget to check the 162nd edition of Paul Hill’s This Week in Rocket Launches.

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Haidt argues that the evidence is in. Teenagers' widespread use of smartphones is causing a mental health crisis. Individual, collective and legislative action is required to limit their smartphone access.

Haidt begins his book with an allegory. Imagine someone offered you the opportunity to have your 10-year-old child grow up on Mars, even though there is every reason to believe that radiation and low gravity could greatly disrupt healthy adolescent development, leading to long-term afflictions. Surely, given the risks, you would refuse the offer.

A decade ago, parents could not have known the threats lying within the shiny new smartphones they presented to their excited teenagers. But the evidence is mounting that the children who grew up with smartphones are struggling.

Haidt calls the period from 2010 to 2015 the "great rewiring." This was a period when adolescents had their neural systems primed for anxiety and depression by extensive daily smartphone use.

The kids aren't alright

Haidt's two central claims are that Gen Z is suffering from a major mental illness epidemic and that smartphones are largely to blame.

Readers should be wary about both these claims—not in the sense that we should resist believing them, but rather we should not be too eager to embrace them. After all, it is perilously easy to believe that the kids aren't alright. Elders routinely despair of the younger generation.

Haidt explicitly acknowledges that other experts have argued against claims of widespread teenage anxiety. In response, he cites recent evidence from a host of different sources: not just self-reports of problems, but hard data on self-harming, suicide rates, diagnosed mental disorders and mental health hospitalizations.

While Haidt focuses on the US, he observes concurrent shifts in youth mental health in many Western countries, including Australia.

But do these findings constitute an epidemic demanding society-wide responses? Here the book would have benefited from systematically drawing together the science in easily understandable terms.

Haidt's marshaled evidence consistently shows a rise, beginning around 2010 and starting with girls, in a host of adolescent mental health disorders and well-being concerns. Broadly speaking, the figures in the US show mental health issues that previously plagued around 5-10% of adolescents growing to afflict around twice that amount.

On the one hand, these data suggest the term "anxious generation" is somewhat misleading. A large majority of Gen Z do not have anxiety disorders—and of those who do, almost half would have done so irrespective of smartphone usage.

On the other hand, the numbers remain concerning. No parent would be comfortable handing their child any substance they knew had a one-in-ten chance of causing the child a mental disorder within a few years. There are also data suggesting that, even among those without disorders, children increasingly suffer from loneliness and other concerning outcomes.

Perhaps the most alarming part of the steep curves and precipitous falls in Haidt's many graphs is not the current figures, but the current trajectories. In almost all cases, things are getting worse. It is possible we may be in the early days of an unfolding catastrophe.

Insert your ideological preference

If we accept there is a serious problem, then the question arises as to its cause. Again, we must resist intuitively appealing answers to this question. The worry is that we will all look into a "witch's mirror," seeing what we want to see or what our preferred ideology tells us we should expect. I am old enough to remember panics about heavy metal music and Dungeons & Dragons.

Indeed, it is possible that Haidt himself fell into this trap, at least in part. In a previous book, The Coddling of the American Mind, Haidt and his co-author Greg Lukianoff argued that harmful worldviews and beliefs prevalent in US educational settings were priming young people for worrying mental health outcomes.

Haidt thinks this coddling remains a factor, but now recognizes the hypothesis fails to fit the data. Specifically, he acknowledges the plummeting mental health of adolescents is evident in many countries, and across all educational levels and social classes.

Are there alternative hypotheses that fit this data? Perhaps kids today are anxious and depressed because they should be anxious and depressed? After all, they inherit a world facing runaway global warming, systemic injustices, insecure work futures and more. Yet Haidt rightly observes that past generations with dire prospects did not show similar mental health outcomes.

Ultimately, the problem is likely to stem from a mix of factors. Haidt argues the current situation was not caused exclusively by smartphone use. Recent decades have also seen the rise of "safetyism"—a term he and Lukianoff coined to describe the preferencing of individual safety ahead of other values—and helicopter parenting. These phenomena have increasingly shielded children from the vital development provided by physical play and unsupervised exploration of the real world.

Haidt argues that parents became fearful of the healthy risks posed by the outside world, even as they catastrophically opened their children up to the unhealthy dangers of the virtual world.

Developmental concerns

Smartphones did not initially raise major developmental concerns for children. The problems started around 2010 when they combined with other factors like social media, high-speed internet, a backward-facing camera (encouraging selfies), addictive games, easily accessible pornography, and free apps that maximize profit by cultivating addiction and social contagion.

This toxic technological mix allowed smartphones to take over children's lives. Usage rates averaging seven hours a day gradually but profoundly rewired their maturing brains. Haidt thinks this rewiring gives rise to four "foundational concerns":

1. Social deprivation: a smartphone is an "experience blocker," taking up hours a day that would otherwise be spent in physical play or in-person conversations with friends and family.
2. Sleep deprivation: too many teenagers stay on their smartphones late at night when they need rest.
3. Attention fragmentation: alerts and messages continually drag teenagers away from the present moment and tasks requiring concentration.
4. Addiction: apps and social media are deliberately designed to hack vulnerabilities in teenagers' psychologies, leading to an inability to enjoy anything else.

Building on these foundational concerns are ones specific to each gender. Girls proved more vulnerable to the damaging effects of social media, while boys retreated into online gaming and pornography.

Dangers to adolescent mental health

An intriguing part of Haidt's book is its account of the way smartphones became addictive and damaging.

Teenagers, like all humans, have several basic needs and emotional drivers: for social connection and inclusion, for a sense of individual empowerment and agency, for sexual fulfillment, and so on.

Haidt explains that, normally, for almost all human history and evolution, these incentives drove teenagers to do things in person, in the real world—things like making friends, playing games together, navigating disputes, getting tasks done, developing romantic attachments and taking physical risks.

While these activities can lead to injuries, tears and frustrations, they are nevertheless important for teenagers' mental health and development. Children are antifragile: they need these types of risks and stressors to grow properly.

Smartphones—and their apps, games and social media—also provide responses to all these drivers. But they do so without prompting the above activities and the important outcomes they deliver, such as close friendships and resilience.

For example, a teenager might feel lonely and want connection, so they join Instagram or TikTok. Social media provides a type of connection and delivers a temporary dopamine hit. But it fulfills the teenager's immediate need in a way that does not involve real world connections and challenges. This only makes them lonelier and more isolated in the longer term.

What can we do?

Even if we accept Haidt's claims about the rise in anxiety fueled by smartphones, it is not clear how we should respond. Perhaps radical solutions are unnecessary. In time, things might work themselves out, such as through further technological innovations.

Haidt's view is that collective action is critical. As he sees it, the problem is not only that smartphones are intrinsically useful and alluring (which is why we all wanted them in the first place); it is not only that their apps are addictive. The problem—especially in a school setting—is that if most of a teenager's peers have smartphones, then the ones who don't have one risk being social outcasts, perpetually "left out" and never "in the know."

For this reason, Haidt thinks actions by isolated parents are unlikely to be successful. Ironically, the same heightened parental concern for child safety Haidt has previously critiqued may prove to be a powerful force for change. At least some parents are likely to view their children's future mental health as a non-negotiable good and treat smartphones as the modern-day hypodermic needle.

For his part, Haidt argues for four new norms, to be created by parents' collective action alongside legislative and regulatory reforms:

1. No smartphones before high school
2. No social media before 16
3. Phone-free schools
4. More independence, free play, and responsibility in the real world.

A deeper problem

Haidt's book leaves the reader with a further, deeper worry.

Suppose he is right that the things that lead to human flourishing involve real world physical encounters with other people: family, close friends, romantic partners, neighbors, local community groups and members.

Such encounters are often unpredictable, messy, inconvenient and frustrating. Conversely, the online world is becoming easier, cheaper and more alluring every day. Innovations and algorithms continually hone our experience, as profit-driven industries work ever more aggressively to capture and keep our attention.

In the face of all this, it may be that the real world can't compete. The mental health concerns currently plaguing Gen Z might turn out to be ones that every generation will face.

If so, Haidt's suggested reforms might mark the first foray in what will be a long battle between the human need for real-world experience and connection, and the powerful temptations of an online world that offers something we can't possibly resist: "a little bit of everything, all of the time".

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features are insufficient at keeping drivers

engaged in the task of driving,

which can often have fatal results.

In March 2023, a North Carolina student was stepping off a school bus when he was struck by a Tesla Model Y traveling at “highway speeds,” according to a federal investigation that published today. The Tesla driver was using Autopilot, the automaker’s advanced driver-assist feature that Elon Musk insists will eventually lead to fully autonomous cars.

The 17-year-old student who was struck was transported to a hospital by helicopter with life-threatening injuries. But what the investigation found after examining hundreds of similar crashes was a pattern of driver inattention, combined with the shortcomings of Tesla’s technology, resulting in hundreds of injuries and dozens of deaths.

Drivers using Autopilot or the system’s more advanced sibling, Full Self-Driving, “were not sufficiently engaged in the driving task,” and Tesla’s technology “did not adequately ensure that drivers maintained their attention on the driving task,” NHTSA concluded.

In total, NHTSA investigated 956 crashes, starting in January 2018 and extending all the way until August 2023. Of those crashes, some of which involved other vehicles striking the Tesla vehicle, 29 people died. There were also 211 crashes in which “the frontal plane of the Tesla struck a vehicle or obstacle in its path.” These crashes, which were often the most severe, resulted in 14 deaths and 49 injuries.

NHTSA was prompted to launch its investigation after several incidents of Tesla drivers crashing into stationary emergency vehicles parked on the side of the road. Most of these incidents took place after dark, with the software ignoring scene control measures, including warning lights, flares, cones, and an illuminated arrow board.

In its report, the agency found that Autopilot — and, in some cases, FSD — was not designed to keep the driver engaged in the task of driving. Tesla says that it warns its customers that they need to pay attention while using Autopilot and FSD, which includes keeping their hands on the wheels and eyes on the road. But NHTSA says that in many cases, drivers would become overly complacent and lose focus. And when it came time to react, it was often too late.

In 59 crashes examined by NHTSA, the agency found that Tesla drivers had enough time, “five or more seconds,” prior to crashing into another object in which to react. In 19 of those crashes, the hazard was visible for 10 or more seconds before the collision. Reviewing crash logs and data provided by Tesla, NHTSA found that drivers failed to brake or steer to avoid the hazard in a majority of the crashes analyzed.

“Crashes with no or late evasive action attempted by the driver were found across all Tesla hardware versions and crash circumstances,” NHTSA said.

NHTSA also compared Tesla’s Level 2 (L2) automation features to products available in other companies’ vehicles. Unlike other systems, Autopilot would disengage rather than allow drivers to adjust their steering. This “discourages” drivers from staying involved in the task of driving, NHTSA said.

“A comparison of Tesla’s design choices to those of L2 peers identified Tesla as an industry outlier in its approach to L2 technology by mismatching a weak driver engagement system with Autopilot’s permissive operating capabilities,” the agency said.

Even the brand name “Autopilot” is misleading, NHTSA said, conjuring up the idea that drivers are not in control. While other companies use some version of “assist,” “sense,” or “team,” Tesla’s products lure drivers into thinking they are more capable than they are. California’s attorney general and the state’s Department of Motor Vehicles are both investigating Tesla for misleading branding and marketing.

NHTSA acknowledges that its probe may be incomplete based on “gaps” in Tesla’s telemetry data. That could mean there are many more crashes involving Autopilot and FSD than what NHTSA was able to find.

Tesla issued a voluntary recall late last year in response to the investigation, pushing out an over-the-air software update to add more warnings to Autopilot. NHTSA said today it was launching a new investigation into the recall after a number of safety experts said the update was inadequate and still allowed for misuse.

The findings cut against Musk’s insistence that Tesla is an artificial intelligence company that is on the cusp of releasing a fully autonomous vehicle for personal use. The company plans to unveil a robotaxi later this year that is supposed to usher in this new era for Tesla. During this week’s first quarter earnings call, Musk doubled down on the notion that his vehicles were safer than human-driven cars.

“If you’ve got, at scale, a statistically significant amount of data that shows conclusively that the autonomous car has, let’s say, half the accident rate of a human-driven car, I think that’s difficult to ignore,” Musk said. “Because at that point, stopping autonomy means killing people.”

Source : https://www.theverge.com/2024/4/26/24141361/tesla-autopilot-fsd-nhtsa-investigation-report-crash-death

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Physicists have deduced subtle hints that the mysterious “dark” energy that drives the universe to expand faster and faster may be slightly weakening with time. It’s a finding that has the potential to shake the foundations of physics.

“If true, it would be the first real clue we have gotten about the nature of dark energy in 25 years,” said Adam Riess, an astrophysicist at Johns Hopkins University who won the Nobel Prize for co-discovering dark energy in 1998.

The new observations come from the Dark Energy Spectroscopic Instrument (DESI) team, which unveiled a map of the cosmos of unprecedented scope, along with a bonanza of measurements derived from the map. To many researchers, the highlight is a plot showing that three different combinations of observations all insinuate that the influence of dark energy may have eroded over the eons.

“It’s possible we’re seeing hints of dark energy evolving,” said Dillon Brout of Boston University, a member of the DESI team.

Researchers inside and outside of the collaboration all stress that the evidence is not strong enough to claim a discovery. The observations favor the erosion of dark energy with the sort of middling statistical significance that could easily vanish with additional data. But researchers also note that three distinct sets of observations all point in the same intriguing direction, one that’s at odds with the standard picture of dark energy as the intrinsic energy of the vacuum of space—the quantity that Albert Einstein dubbed the “cosmological constant” due to its unvarying nature.

“It’s exciting,” said Sesh Nadathur, a cosmologist at the University of Portsmouth who worked on the DESI analysis. “If dark energy is not a cosmological constant, that’s going to be a huge discovery.”

Rise of the Cosmological Constant

In 1998, Riess’ group, along with another team of astronomers led by Saul Perlmutter, used the light of dozens of distant, dying stars called supernovas to illuminate the structure of the cosmos. They discovered that the expansion of the universe is growing faster as it ages.

According to Einstein’s general theory of relativity, any matter or energy can drive cosmic expansion. But as space expands, all the familiar kinds of matter and energy become less dense as they spread out in a roomier universe. As their densities fall, the expansion of the universe should slow down, not speed up.

One substance that does not become diluted with the expansion of space, however, is space itself. If the vacuum has an energy of its own, then as more vacuum (and therefore more energy) is created, the expansion will speed up, just as Riess’ and Perlmutter’s teams observed. Their discovery of the accelerating expansion of the universe revealed the presence of a tiny amount of energy associated with the vacuum of space—dark energy.

Conveniently, Einstein had considered such a possibility while developing general relativity. To stop the dilution of matter from collapsing the universe, he imagined that all of space might be infused with a fixed amount of extra energy, represented by the symbol Λ, called lambda, and referred to as the cosmological constant. Einstein’s intuition turned out to be off, as the universe isn’t balanced in the way he imagined. But after the 1998 discovery that space seems to be pushing everything outward, his cosmological constant returned and took its place at the heart of the current standard model of cosmology, a set of intertwined ingredients named the “Lambda CDM model.”

“It’s simple. It’s one number. It has some story you can attach to it. That’s why it’s believed to be constant,” said Licia Verde, a theoretical cosmologist and member of the DESI collaboration.

Now a new generation of cosmologists wielding a new generation of telescopes may be picking up the first whispers of a richer story.

Mapping the Heavens

One of those telescopes sits on Kitt Peak in Arizona. The DESI team has outfitted the telescope’s four-meter mirror with 5,000 robotic fibers that automatically swivel toward their celestial targets. The automation enables lightning-fast data collection as compared with the previous flagship galaxy survey, the Sloan Digital Sky Survey (SDSS), which relied on similar fibers that had to be plugged in to patterned metal plates by hand. On one recent record-setting night, DESI was able to record the locations of nearly 200,000 galaxies.

From May 2021 to June 2022, the robotic fibers slurped up photons arriving at Earth from different eras of cosmic history. The DESI researchers have since transformed that data into the most detailed cosmic map ever made. It features the precise locations of about 6 million galaxies as they existed between roughly 2 and 12 billion years ago (out of the universe’s 13.8 billion–year history). “DESI is a really great experiment producing stupendous data,” said Riess.

Earth is at the center of this thin slice of DESI’s 3D map of the universe. Magnification reveals the distribution

of galaxies and voids.

Courtesy of Claire Lamman/DESI collaboration; custom colormap package by cmastro

The secret to DESI’s precision mapping is its ability to collect spectra of galaxies—data-rich plots recording the intensity of each hue of light. A spectrum reveals how quickly a galaxy is moving away from us and therefore which era of cosmic history we’re seeing it in (the faster a galaxy is receding, the older it is). That lets you situate the galaxies relative to each other, but to calibrate the map with the correct distances relative to Earth—essential information for a full reconstruction of cosmic history—you need something else.

For the DESI collaboration, that something was a patchwork of frozen density ripples left behind from the early universe. For the first couple hundred thousand years after the Big Bang, the cosmos was a hot, thick soup of mostly matter and light. Gravity pulled the matter inward while light pushed it outward, and the struggle set off density ripples spreading outward from a smattering of initial dense spots in the soup. After the universe cooled and atoms formed, it became transparent. Light streamed outward, leaving the ripples—called baryonic acoustic oscillations (BAOs)—frozen in place.

The end result was a series of overlapping spheres with slightly denser shells measuring roughly a billion light-years across—the distance BAOs had time to travel before freezing. Those dense shells went on to form slightly more galaxies than other locations did, and when DESI researchers map millions of galaxies, they can detect traces of these spheres. Closer spheres appear bigger than distant ones, but since DESI researchers know the spheres are all the same size, they can tell how far away from Earth the galaxies really are and resize the map accordingly.

To avoid unconsciously influencing their results, the researchers conducted a “blind” analysis, working with measurements that had been randomly shuffled around to obscure any physical patterns. Then the collaboration met in Hawaii last December to unscramble the results and see what sort of map the Kitt Peak robotic fibers had observed.

Nadathur, who was watching live over Zoom from his home in the United Kingdom, felt a thrill when the map was revealed, because it seemed a bit strange. “If you had enough experience with BAO data, you could see that something was going to be needed that was a bit different from the standard model,” Nadathur said. “I knew that Lambda CDM wasn’t quite the whole picture.”

Over the following week, as the researchers combed through the new data set, analyzing it and blending it with other large cosmological data sets, they discovered the source of the oddness and exchanged a flurry of Slack messages.

“One of my colleagues posted a plot showing this dark energy constraint and didn’t write any words. Just the plot and an exploding head emoji,” Nadathur said.

Data for Days

DESI aims to pin down how the universe has expanded over time by observing different types of galaxies as they appeared during seven epochs of cosmological history. They then see how well these seven snapshots line up with the evolution predicted by Lambda CDM. They also consider how well other theories do—such as theories that allow dark energy to vary between snapshots.

With the first year of DESI data alone, Lambda CDM fits the snapshots nearly as well as a variable dark matter model. It’s only when the collaboration combines the DESI map with other snapshots—light known as the cosmic microwave background and a series of three recent supernova maps—that the two theories start to drift apart.

They found that the results varied from the prediction of Lambda CDM by 2.5, 3.5, or 3.9 “sigmas,” depending on which of the three supernova catalogs they included. Imagine flipping a coin 100 times. The prediction for a fair coin is 50 heads and 50 tails. If you get 60 heads, that’s two sigma away from the mean; the odds of it happening by chance (as opposed to the coin being rigged) are 1 in 20. If you get 75 heads—which has a 1-in-2,000,000 chance of happening randomly—that’s a five-sigma result, the gold standard for claiming a discovery in physics. The sigma values DESI obtained fall somewhere in between; they could be rare statistical fluctuations or real evidence that dark energy is changing.

The DESI instrument is equipped with thousands of robotic

fibers to dramatically speed up data collection.

Courtesy of Marilyn Sargent/The Regents of the University

of California, Lawrence Berkeley National Laboratory

While researchers find these numbers tantalizing, they also warn against reading too much into the higher values. The universe is a lot more complicated than a coin, and the statistical significances depend on subtle assumptions in the data analysis.

A stronger reason for enthusiasm is the fact that all three supernova catalogs—which span somewhat independent populations of supernovas—hint that dark energy is varying in the same way: Its power is waning, or as cosmologists say, “thawing.” “When we swap out all of these complementary data sets, they all tend to converge on this slightly negative number,” Brout said. If the discrepancy were random, the data sets would be more likely to point in different directions.

Joshua Frieman, a cosmologist at the University of Chicago and a member of the DESI collaboration who didn’t work on the data analysis, said he would be glad to see Lambda CDM fall. As a theorist, he proposed theories of thawing dark energy in the 1990s, and he more recently cofounded the Dark Energy Survey—a project that searched for deviations from the standard model from 2013 to 2019 and created one of the three supernova catalogs DESI used. But he also remembers being burnt by disappearing cosmological anomalies in the past. “My reaction to this is to be intrigued,” but “until the errors get smaller, I’m not going to write my [Nobel] acceptance speech,” Frieman joked.

“Statistically speaking, it could disappear,” Brout said of the discrepancy with the Lambda CDM model. “We are now going all out to find out if it will.”

After wrapping up their third year of observations earlier this week, the DESI researchers expect that their next map will contain nearly twice as many galaxies as the map unveiled today. And now that they have more experience doing the BAO analysis, they plan to get the updated three-year map out quickly. Next comes a five-year map of 40 million galaxies.

Beyond DESI, a slew of new instruments are coming online in the coming years, including the 8.4-meter Vera Rubin Observatory in Chile, NASA’s Nancy Grace Roman Space Telescope, and the European Space Agency’s Euclid mission.

“Our data in cosmology has made enormous leaps over the last 25 years, and it’s about to make bigger leaps,” Frieman said.

As they amass new observations, researchers may continue to find that dark energy appears as constant as it has for a generation. Or, if the trend continues in the direction suggested by DESI’s results, it could change everything.

New Physics

If dark energy is weakening, it can’t be a cosmological constant. Instead, it may be the same sort of field that many cosmologists think sparked a moment of exponential expansion during the universe’s birth. This kind of “scalar field” could fill space with an amount of energy that looks constant at first—like the cosmological constant—but eventually starts to slip over time.

“The idea that dark energy is varying is very natural,” said Paul Steinhardt, a cosmologist at Princeton University. Otherwise, he continued, “it would be the only form of energy we know which is absolutely constant in space and time.”

But that variability would bring about a profound paradigm shift: We would not be living in a vacuum, which is defined as the lowest-energy state of the universe. Instead, we would inhabit an energized state that’s slowly sliding toward a true vacuum. “We’re used to thinking that we’re living in the vacuum,” Steinhardt said, “but no one promised you that.”

The fate of the cosmos would depend on how quickly the number previously known as the cosmological constant declines, and how far it might go. If it reaches zero, cosmic acceleration would stop. If it dips far enough below zero, the expansion of space would turn to a slow contraction—the sort of reversal required for cyclic theories of cosmology, such as those developed by Steinhardt.

String theorists share a similar outlook. With their proposal that everything boils down to the vibration of strings, they can weave together universes with different numbers of dimensions and all manner of exotic particles and forces. But they can’t easily construct a universe that permanently maintains a stable positive energy, as our universe has seemed to. Instead, in string theory, the energy must either gently fall over the course of billions of years or violently drop to zero or a negative value. “Essentially, all string theorists believe that it’s one or the other. We do not know which one,” said Cumrun Vafa of Harvard University.

Observational evidence for a gradual decline of dark energy would be a boon for the gentle-fall scenario. “That would be amazing. It would be the most important discovery since the discovery of dark energy itself,” Vafa said.

But for now, any such speculations are rooted in the DESI analysis in only the loosest of ways. Cosmologists will have to observe many millions more galaxies before seriously entertaining thoughts of revolution.

“If this holds up, it could light the way to a new, potentially deeper understanding of the universe,” Riess said. “The next few years should be very revealing.”

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Sunday, 28 April

• Who: SpaceX
• What: Falcon 9
• When: 12:34 a.m. UTC
• Where: Florida, US
• Why: SpaceX will be using a Falcon 9 to launch Galileo 29 and 30 for the European Space Agency. They will make up part of the Galileo navigation constellation, which complements the United States GPS satellites on smartphones and so on for positioning purposes.

• Who: SpaceX
• What: Falcon 9
• When: 9:50 p.m. - 1:50 a.m. UTC
• Where: Florida, US
• Why: SpaceX will be launching Starlink satellites into a low Earth orbit. This group of 23 satellites is known as Starlink Group 6-54; this identifier can be used on apps like ISS Detector to see when they will be flying over your house. After take-off, SpaceX will attempt to launch the first stage of the Falcon 9 so that it can be reused. These satellites beam internet back down to Starlink customers on Earth.

Wednesday, 1 May

• Who: SpaceX
• What: Falcon 9
• When: 6:30 p.m. - 11:00 p.m. UTC
• Where: California, US
• Why: SpaceX will use a Falcon 9 to launch the first two WorldView Legion Earth observation satellites for Maxar Technologies. They will be placed into a Sun-synchronous orbit, where they will perform different monitoring activities such as the surveillance of natural disasters, pollution, and oil spills and detect activities such as illegal fishing, piracy, drug smuggling, or human trafficking. There will be six satellites in this constellation eventually.

Friday, 3 May

• Who: CNSA
• What: Long March 5
• When: 8:00 a.m. UTC
• Where: Wenchang, China
• Why: China will launch the Chang’e 3 sample return mission to the Moon. It’s the country’s seventh mission of its robotic lunar exploration programme, Chang’e. This mission is complex, two modules will stay in lunar orbit while a sample collector and ascent vehicle will land at the Aitken basin at the south pole. The collector will drill two metres underground for a sample, and the ascent vehicle will take it back up to the modules in orbit, which will then fly the samples back to Earth for inspection.

Saturday, 4 May

• Who: SpaceX
• What: Falcon 9
• When: 2:59 a.m. UTC
• Where: California, US
• Why: SpaceX will use a Falcon 9 to launch 22 Starlink satellites to a low Earth orbit. It could include more direct-to-cell Starlink satellites, which we have spoken about before. Like other Starlink missions, the first stage of the Falcon 9 should land back on Earth ready for reuse.

Recap

• The first launch we got last week was a Falcon 9 carrying Starlink satellites to orbit. After the launch, the first stage of the rocket performed a landing for reuse.

• Next, a Rocket Lab Electron rocket launched NASA’s Advanced Composite Solar Sail System (ACS3) and KAIST’s NeonSat-1 Earth observation satellite from Mahia, New Zealand.

• Finally, China launched a Long March 2F Y18 topped with the Shenzhou-18 crew spacecraft to its space station. The astronauts being launched included Guangfu Ye, Cong Li, and Guangsu Li.

That’s all we have this week. Be sure to check in next time!

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Long-term daily use of aspirin can help to prevent the development and progression of colorectal cancer, but the mechanisms involved have been unclear. New research has revealed that aspirin may exert these protective effects by boosting certain aspects of the body’s immune response against cancer cells. The findings are published by Wiley online in CANCER, a peer-reviewed journal of the American Cancer Society.  

To investigate the effects of aspirin (a nonsteroidal anti-inflammatory drug) on colorectal cancer, investigators in Italy obtained tissue samples from 238 patients who underwent surgery for colorectal cancer in 2015–2019, 12% of whom were aspirin users. Patients were enrolled in the METACCRE section of the IMMUNOlogical microenvironment in the REctal Adenocarcinoma Treatment (IMMUNOREACT multicenter observational study. The study was funded by the Associazione Italiana per la Ricerca sul Cancro (AIRC) and was mainly carried out at the University Hospital of Padova. 

Compared with tissue samples from patients who did not use aspirin, samples from aspirin users showed less cancer spread to the lymph nodes and higher infiltration of immune cells into tumors. In analyses of colorectal cancer cells in the lab, exposing the cells to aspirin caused increased expression of a protein called CD80 on certain immune cells, which enhanced the capacity of the cells to alert other immune cells of the presence of tumor-associated proteins. Supporting this finding, the researchers found that in patients with rectal cancer, aspirin users had higher CD80 expression in healthy rectal tissue, suggesting a pro-immune surveillance effect of aspirin. 

Our study shows a complementary mechanism of cancer prevention or therapy with aspirin besides its classical drug mechanism involving inhibition of inflammation. Aspirin is absorbed in the colon by passive diffusion to a significant degree. Its absorption is linear and depends on concentration along the bowel, and in the rectum, the concentration of orally administered aspirin can be much lower than in the rest of the colon. Thus, if we want to take advantage of its effects against colorectal cancer, we should think of how to guarantee that aspirin reaches the colorectal tract in adequate doses to be effective.” 

Marco Scarpa MD, PhD, Principal Investigator, University of Padova

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While the evidence hasn’t been conclusive, previous research has suggested a link between vitamin D deficiency and human cancer risk.

The researchers investigated this by analyzing a dataset from 1.5 million Denmark citizens. This revealed a connection between decreased vitamin D levels and an increased risk of cancer. According to a different examination of a patient group with the disease, individuals with greater vitamin D levels2 were also suggested to be more likely to benefit from immune-based cancer treatments.

More investigation is required to determine whether vitamin D contributes to some immunological resistance to cancer through the same method, even though Bacteroides fragilis is also present in the human microbiome.

Scientists from the National Cancer Institute (NCI) of the United States National Institutes of Health (NIH), the Francis Crick Institute, and Aalborg University in Denmark have discovered that vitamin D promotes the development of a particular kind of gut bacteria in mice that improves their resistance to cancer.

According to the researchers, mice fed a diet high in vitamin D showed enhanced immunological resistance against experimentally implanted tumors and increased responses to immunotherapy treatment. The removal of a protein that binds to vitamin D in the blood through gene editing also had this impact.

The group discovered, rather surprisingly, that vitamin D stimulates intestinal epithelial cells, boosting the population of a bacterium known as Bacteroides fragilis. The transplanted tumors in the mice showed less growth, suggesting that this bacterium improved their resistance to cancer. However, the exact mechanism is yet unknown.

Mice on a regular diet were given Bacteroides fragilis to see if the bacterium alone may improve cancer immunity. Additionally, these mice showed greater resistance to tumor formation; however, this did not hold true when the mice were fed a diet low in vitamin D.

Caetano Reis e Sousa, head of the Immunobiology Laboratory at the Crick and senior author, said: “What we’ve shown here came as a surprise—vitamin D can regulate the gut microbiome to favor a type of bacteria that gives mice better immunity to cancer.

“This could one day be important for cancer treatment in humans, but we don’t know how and why vitamin D has this effect via the microbiome. More work is needed before we can conclusively say that correcting a vitamin D deficiency has benefits for cancer prevention or treatment.”

Evangelos Giampazolias, a former postdoctoral researcher at the Crick and now Group Leader of the Cancer Immunosurveillance Group at the Cancer Research UK Manchester Institute, said: “Pinpointing the factors that distinguish a ‘good’ from a ‘bad’ microbiome is a major challenge. We found that vitamin D helps gut bacteria elicit cancer immunity, improving the response to immunotherapy in mice.

“A key question we are currently trying to answer is how exactly vitamin D supports a ‘good’ microbiome. If we can answer this, we might uncover new ways in which the microbiome influences the immune system, potentially offering exciting possibilities in preventing or treating cancer.”

Romina Goldszmid, Stadtman Investigator in NCI’s Center For Cancer Research, said: “These findings contribute to the growing body of knowledge on the role of microbiota in cancer immunity and the potential of dietary interventions to fine-tune this relationship for improved patient outcomes. However, further research is warranted to fully understand the underlying mechanisms and how they can be harnessed to develop personalized treatment strategies.”

Research Information Manager at Cancer Research UK, Dr Nisharnthi Duggan said: “We know that vitamin D deficiency can cause health problems, however, there isn’t enough evidence to link vitamin D levels to cancer risk. This early-stage research in mice, coupled with an analysis of Danish population data, seeks to address the evidence gap. While the findings suggest a possible link between vitamin D and immune responses to cancer, further research is needed to confirm this.

“A bit of sunlight can help our bodies make vitamin D, but you don’t need to sunbathe to boost this process. Most people in the UK can make enough vitamin D by spending short periods of time in the summer sun. We can also get vitamin D from our diet and supplements. We know that staying safe in the sun can reduce the risk of cancer, so seek shade, cover up and apply sunscreen when the sun is strong.”

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