Enlarge / The cycle of building and breaking up of supercontinents seems to drive long-term climate trends. (credit: Walter Myers/Stocktrek Images)

Global temperature records go back less than two centuries. But that doesn't mean we have no idea what the world was doing before we started building thermometers. There are various things—tree rings, isotope ratios, and more—that register temperatures in the past. Using these temperature proxies, we've managed to reconstruct thousands of years of our planet's climate.

But going back further is difficult. Fewer proxies get preserved over longer times, and samples get rarer. By the time we go back past a million years, it's difficult to find enough proxies from around the globe and the same time period to reconstruct a global temperature. There are a few exceptions, like the Paleocene-Eocene Thermal Maximum (PETM), a burst of sudden warming about 55 million years ago, but few events that old are nearly as well understood.

Now, researchers have used a combination of proxy records and climate models to reconstruct the Earth's climate for the last half-billion years, providing a global record of temperatures stretching all the way back to near the Cambrian explosion of complex life. The record shows that, with one apparent exception, carbon dioxide and global temperatures have been tightly linked. Which is somewhat surprising, given the other changes the Earth has experienced over this time.

Enlarge / Artist's conception of a dark matter filament containing a galaxy with large jets. (Caltech noted that some details of this image were created using AI.) (credit: Martijn Oei (Caltech) / Dylan Nelson (IllustrisTNG Collaboration).)

The supermassive black holes that sit at the center of galaxies aren't just decorative. The intense radiation they emit when feeding helps drive away gas and dust that would otherwise form stars, providing feedback that limits the growth of the galaxy. But their influence may extend beyond the galaxy they inhabit. Many black holes produce jets and, in the case of supermassive versions, these jets can eject material entirely out of the galaxy.

Now, researchers are getting a clearer picture of just how far outside of the galaxy their influence can reach. A new study describes the largest-ever jets observed, extending across a total distance of 23 million light-years (seven megaparsecs). At those distances, the jets could easily send material into other galaxies and across the cosmic web of dark matter that structures the Universe.

Extreme jets

Jets are formed in the complex environment near a black hole. The intense heating of infalling material ionizes and heats it, creating electromagnetic fields that act as a natural particle accelerator. This creates jets of particles that travel at a substantial fraction of the speed of light. These will ultimately slam into nearby material, creating shockwaves that heat and accelerate that, too. Over time, this leads to large-scale, coordinated outflows of material, with the scale of the jet being proportional to a combination of the size of the black hole and the amount of material it is feeding on.

Enlarge / Harvard Business School was targeted by a faculty member's lawsuit. (credit: APCortizasJr)

Earlier this year, we got a look at something unusual: the results of an internal investigation conducted by Harvard Business School that concluded one of its star faculty members had committed research misconduct. Normally, these reports are kept confidential, leaving questions regarding the methods and extent of data manipulations.

But in this case, the report became public because the researcher had filed a lawsuit that alleged defamation on the part of the team of data detectives that had first identified potential cases of fabricated data, as well as Harvard Business School itself. Now, the court has ruled on motions to dismiss the case. While the suit against Harvard will go on, the court has ruled that evidence-backed conclusions regarding fabricated data cannot constitute defamation—which is probably a very good thing for science.

Data and defamation

The researchers who had been sued, Uri Simonsohn, Leif Nelson, and Joe Simmons, run a blog called Data Colada where, among other things, they note cases of suspicious-looking data in the behavioral sciences. As we detailed in our earlier coverage, they published a series of blog posts describing an apparent case of fabricated data in four different papers published by the high-profile researcher Francesca Gino, a professor at Harvard Business School.

Enlarge (credit: Jarcosa)

Rapa Nui, often referred to as Easter Island, is one of the most remote populated islands in the world. It's so distant that Europeans didn't stumble onto it until centuries after they had started exploring the Pacific. When they arrived, though, they found that the relatively small island supported a population of thousands, one that had built imposing monumental statues called moai. Arguments over how this population got there and what happened once it did have gone on ever since.

Some of these arguments, such as the idea that the island's indigenous people had traveled there from South America, have since been put to rest. Genomes from people native to the island show that its original population was part of the Polynesian expansion across the Pacific. But others, such as the role of ecological collapse in limiting the island's population and altering its culture, continue to be debated.

Researchers have now obtained genome sequence from the remains of 15 Rapa Nui natives who predate European contact. And they indicate that the population of the island appears to have grown slowly and steadily, without any sign of a bottleneck that could be associated with an ecological collapse. And roughly 10 percent of the genomes appear to have a Native American source that likely dates from roughly the same time that the island was settled.

Enlarge / Quantinuum's H2 "racetrack" quantum processor. (credit: Quantinuum)

On Tuesday, Microsoft made a series of announcements related to its Azure Quantum Cloud service. Among them was a demonstration of logical operations using the largest number of error-corrected qubits yet.

"Since April, we've tripled the number of logical qubits here," said Microsoft Technical Fellow Krysta Svore. "So we are accelerating toward that hundred-logical-qubit capability." The company has also lined up a new partner in the form of Atom Computing, which uses neutral atoms to hold qubits and has already demonstrated hardware with over 1,000 hardware qubits.

Collectively, the announcements are the latest sign that quantum computing has emerged from its infancy and is rapidly progressing toward the development of systems that can reliably perform calculations that would be impractical or impossible to run on classical hardware. We talked with people at Microsoft and some of its hardware partners to get a sense of what's coming next to bring us closer to useful quantum computing.

Enlarge / The eruptions that produced the dark mare on the lunar surface ended billions of years ago. (credit: NASA/GSFC/Arizona State University)

Signs of volcanic activity on the Moon can be viewed simply by looking up at the night-time sky: The large, dark plains called "maria" are the product of massive outbursts of volcanic material. But these were put in place relatively early in the Moon's history, with their formation ending roughly 3 billion years ago. Smaller-scale additions may have continued until roughly 2 billion years ago. Evidence of that activity includes samples obtained by China's Chang'e-5 lander.

But there are hints that small-scale volcanism continued until much more recent times. Observations from space have identified terrain that seems to be the product of eruptions, but only has a limited number of craters, suggesting a relatively young age. But there's considerable uncertainty about these deposits.

Now, further data from samples returned to Earth by the Chang’e-5 mission show clear evidence of volcanism that is truly recent in the context of the history of the Solar System. Small beads that formed during an eruption have been dated to just 125 million years ago.

Enlarge / A lot of gold deposits are found embedded in quartz crystals. (credit: Pierre Longnus)

One of the reasons gold is so valuable is because it is highly unreactive—if you make something out of gold, it keeps its lustrous radiance. Even when you can react it with another material, it's also barely soluble, a combination that makes it difficult to purify away from other materials. Which is part of why a large majority of the gold we've obtained comes from deposits where it is present in large chunks, some of them reaching hundreds of kilograms.

Those of you paying careful attention to the previous paragraph may have noticed a problem here: If gold is so difficult to get into its pure form, how do natural processes create enormous chunks of it? On Monday, a group of Australian researchers published a hypothesis, and a bit of evidence supporting it. They propose that an earthquake-triggered piezoelectric effect essentially electroplates gold onto quartz crystals.

The hypothesis

Approximately 75 percent of the gold humanity has obtained has come from what are called orogenic gold deposits. Orogeny is a term for the tectonic processes that build mountains, and orogenic gold deposits form in the seams where two bodies of rock are moving past each other. These areas are often filled with hot hydrothermal fluids, and the heat can increase the solubility of gold from "barely there" to "extremely low," meaning generally less than a single milligram in a liter of water.

Enlarge (credit: Aurich Lawson | Getty Images)

As far back as 2016, work on AI-based chatbots revealed that they have a disturbing tendency to reflect some of the worst biases of the society that trained them. But as large language models have become ever larger and subjected to more sophisticated training, a lot of that problematic behavior has been ironed out. For example, I asked the current iteration of ChatGPT for five words it associated with African Americans, and it responded with things like "resilience" and "creativity."

But a lot of research has turned up examples where implicit biases can persist in people long after outward behavior has changed. So some researchers decided to test whether the same might be true of LLMs. And was it ever.

By interacting with a series of LLMs using examples of the African American English sociolect, they found that the AI's had an extremely negative view of its speakers—something that wasn't true of speakers of another American English variant. And that bias bled over into decisions the LLMs were asked to make about those who use African American English.

(credit: DOE)

While solar power is growing at an extremely rapid clip, in absolute terms, the use of natural gas for electricity production has continued to outpace renewables. But that looks set to change in 2024, as the US Energy Information Agency (EIA) has run the numbers on the first half of the year and found that wind, solar, and batteries were each installed at a pace that dwarfs new natural gas generators. And the gap is expected to get dramatically larger before the year is over.

Solar, batteries booming

According to the EIA's numbers, about 20 GW of new capacity was added in the first half of this year, and solar accounts for 60 percent of it. Over a third of the solar additions occurred in just two states, Texas and Florida. There were two projects that went live that were rated at over 600 MW of capacity, one in Texas, the other in Nevada.

Next up is batteries: The US saw 4.2 additional gigawatts of battery capacity during this period, meaning over 20 percent of the total new capacity. (Batteries are treated as the equivalent of a generating source by the EIA since they can dispatch electricity to the grid on demand, even if they can't do so continuously.) Texas and California alone accounted for over 60 percent of these additions; throw in Arizona and Nevada, and you're at 93 percent of the installed capacity.

Enlarge / The African Lungfish, showing it's thin, wispy fins. (credit: feathercollector)

When it was first discovered, the coelacanth caused a lot of excitement. It was a living example of a group of fish that was thought to only exist as fossils. And not just any group of fish. With their long, stalk-like fins, coelacanths and their kin are thought to include the ancestors of all vertebrates that aren't fish—the tetrapods, or vertebrates with four limbs. Meaning, among a lot of other things, us.

Since then, however, evidence has piled up that we're more closely related to lungfish, which live in freshwater and are found in Africa, Australia, and South America. But lungfish are a bit weird. The African and South American species have seen the limb-like fins of their ancestors reduced to thin, floppy strands. And getting some perspective on their evolutionary history has proven difficult because they have the largest genomes known in animals, with the South American lungfish genome containing over 90 billion base pairs. That's 30 times the amount of DNA we have.

But new sequencing technology has made tackling that sort of challenge manageable, and an international collaboration has now completed the largest genome ever, one where all but one chromosome carry more DNA than is found in the human genome. The work points to a history where the South American lungfish has been adding 3 billion extra bases of DNA every 10 million years for the last 200 million years, all without adding a significant number of new genes. Instead, it seems to have lost the ability to keep junk DNA in check.

Enlarge / Without adjustments for relativity, clocks here and on the Moon would rapidly diverge. (credit: NASA)

Timing is everything these days. Our communications and GPS networks all depend on keeping careful track of the precise timing of signals—including accounting for the effects of relativity. The deeper into a gravitational well you go, the slower time moves, and we've reached the point where we can detect differences in altitude of a single millimeter. Time literally flows faster at the altitude where GPS satellites are than it does for clocks situated on Earth's surface. Complicating matters further, those satellites are moving at high velocities, an effect that slows things down.

It's relatively easy to account for that on the Earth, where we're dealing with a single set of adjustments that can be programmed into electronics that need to keep track of these things. But plans are in place to send a large array of hardware to the Moon, which has a considerably lower gravitational field (faster clocks!), which means that objects can stay in orbit despite moving more slowly (also faster clocks!).

It would be easy to set up an equivalent system to track time on the Moon, but that would inevitably see the clocks run out of sync with those on Earth—a serious problem for things like scientific observations. So, the International Astronomical Union has a resolution that calls for a "Lunar Celestial Reference System" and "Lunar Coordinate Time" to handle things there. On Monday, two researchers at the National institute of Standards and Technology, Neil Ashby and Bijunath Patla, did the math to show how this might work.

Enlarge / In the experiments, people had to judge what constituted a fair monetary offer. (credit: manusapon kasosod)

In many cases, AIs are trained on material that's either made or curated by humans. As a result, it can become a significant challenge to keep the AI from replicating the biases of those humans and the society they belong to. And the stakes are high, given we're using AIs to make medical and financial decisions.

But some researchers at Washington University in St. Louis have found an additional wrinkle in these challenges: The people doing the training may potentially change their behavior when they know it can influence the future choices made by an AI. And, in at least some cases, they carry the changed behaviors into situations that don't involve AI training.

Would you like to play a game?

The work involved getting volunteers to participate in a simple form of game theory. Testers gave two participants a pot of money—$10, in this case. One of the two was then asked to offer some fraction of that money to the other, who could choose to accept or reject the offer. If the offer was rejected, nobody got any money.

Enlarge / Absolute temperatures show how similar July 2023 and 2024 were. (credit: C3S/ECMWF)

The past several years have been absolute scorchers, with 2023 being the warmest year ever recorded. And things did not slow down in 2024. As a result, we entered a stretch where every month set a new record as the warmest iteration of that month that we've ever recorded. Last month, that pattern stretched out for a full 12 months, as June of 2024 once again became the warmest June ever recorded. But, despite some exceptional temperatures in July, it fell just short of last July's monthly temperature record, bringing the streak to a close.

Europe's Copernicus system was first to announce that July of 2024 was ever so slightly cooler than July of 2023, missing out on setting a new record by just 0.04° C. So far, none of the other major climate trackers, such as Berkeley Earth or NASA GISS, have come out with data for July. These each have slightly different approaches to tracking temperatures, and, with a margin that small, it's possible we'll see one of them register last month as warmer or statistically indistinguishable.

How exceptional are the temperatures of the last few years? The EU averaged every July from 1991 to 2020—a period well after climate change had warmed the planet significantly—and July of 2024 was still 0.68° C above that average.

Enlarge / Half of the upper arm bone of this species can fit comfortably in the palm of a modern human hand. (credit: Yousuke Kaifu)

The discovery of Homo floresiensis, often termed a hobbit, confused a lot of people. Not only was it tiny in stature, but it shared some features with both Homo erectus and earlier Australopithecus species and lived well after the origin of modern humans. So, its precise position within the hominin family tree has been the subject of ongoing debate—one that hasn't been clarified by the discovery of the similarly diminutive Homo luzonensis in the Philippines.

Today, researchers are releasing a paper that describes bones from a diminutive hominin that occupied the island of Flores much earlier than the hobbits. And they argue that, while it still shares an odd mix of features, it is most closely related to Homo erectus, the first hominin species to spread across the globe.

Remarkably small

The bones come from a site on Flores called Mata Menge, where the bones were found in a large layer of sediment. Slight wear suggests that many of them were probably brought to the site by a gentle flood. Dating from layers above and below where the fossils were found limits their age to somewhere between 650,000 and 775,000 years ago. Most of the remains are teeth and fragments of jaw bone, which can be suggestive of body size, but not definitive. But the new finds include a fragment of the upper arm bone, the humerus, which is more directly proportional to body size.

Enlarge / Some solar panels, along with a diagram of a perovskite's crystal structure. (credit: Subhakitnibhat Kewiko)

As the price of silicon panels has continued to come down, we've reached the point where they're a small and shrinking cost of building a solar farm. That means that it might be worth spending more to get a panel that converts more of the incoming sunlight to electricity, since it allows you to get more out of the price paid to get each panel installed. But silicon panels are already pushing up against physical limits on efficiency. Which means our best chance for a major boost in panel efficiency may be to combine silicon with an additional photovoltaic material.

Right now, most of the focus is on pairing silicon with a class of materials called perovskites. Perovskite crystals can be layered on top of silicon, creating a panel with two materials that absorb different areas of the spectrum—plus, perovskites can be made from relatively cheap raw materials. Unfortunately, it has been difficult to make perovskites that are both high-efficiency and last for the decades that the silicon portion will.

Lots of labs are attempting to change that, though. And two of them reported some progress this week, including a perovskite/silicon system that achieved 34 percent efficiency.

Enlarge / Some of the galaxies in the JADES images. (credit: NASA, ESA, CSA, M. Zamani)

One of the things that the James Webb Space Telescope was designed to do was look at some of the earliest objects in the Universe. And it has already succeeded spectacularly, imaging galaxies as they existed just 250 million years after the Big Bang. But these galaxies were small, compact, and similar in scope to what we'd consider a dwarf galaxy today, which made it difficult to determine what was producing their light: stars or an actively feeding supermassive black hole at their core.

This week, Nature is publishing confirmation that some additional galaxies we've imaged also date back to just 300 million years after the Big Bang. Critically, one of them is bright and relatively large, allowing us to infer that most of its light was coming from a halo of stars surrounding its core, rather than originating in the same area as the central black hole. The finding implies that it formed through a continuing burst of star formation that started just 200 million years after the Big Bang.

Age checks

The galaxies at issue here were first imaged during the JADES (JWST Advanced Deep Extragalactic Survey) imaging program, which includes part of the area imaged for the Hubble Ultra Deep Field. Initially, old galaxies were identified by using a combination of filters on one of Webb's infrared imaging cameras.

Enlarge (credit: Vithun Khamsong)

With the plunging price of photovoltaics, the construction of solar plants has boomed in the US. Last year, for example, the US's Energy Information Agency expected that over half of the new generating capacity would be solar, with a lot of it coming online at the very end of the year for tax reasons. Yesterday, the EIA released electricity generation numbers for the first five months of 2024, and that construction boom has seemingly made itself felt: generation by solar power has shot up by 25 percent compared to just one year earlier.

The EIA breaks down solar production according to the size of the plant. Large grid-scale facilities have their production tracked, giving the EIA hard numbers. For smaller installations, like rooftop solar on residential and commercial buildings, the agency has to estimate the amount produced, since the hardware often resides behind the metering equipment, so only shows up via lower-than-expected consumption.

In terms of utility-scale production, the first five months of 2024 saw it rise by 29 percent compared to the same period in the year prior. Small-scale solar was "only" up by 18 percent, with the combined number rising by 25.3 percent.

Enlarge / Image of Epsilon Indi A at two wavelengths, with the position of its host star indicated by an asterisk. (credit: T. Müller (MPIA/HdA), E. Matthews (MPIA))

We have a couple of techniques that allow us to infer the presence of an exoplanet based on its effects on the light coming from its host star. But there's an alternative approach that sometimes works: image them directly. It's much more limited, since the planet has to be pretty big and orbiting far away enough from its star to avoid having light coming from the planet swamped by the far more intense starlight.

Still, it has been done. Massive exoplanets have been captured relatively shortly after their formation, when the heat generated by the collapse of material into the planet causes them to glow in the infrared. But the Webb telescope is far more sensitive than any infrared observatory we've ever built, and it has managed to image a relatively nearby exoplanet that's roughly as old as the ones in our Solar System.

Looking directly at a planet

What do you need to directly image a planet that's orbiting a star light-years away? The first thing is a bit of hardware called a coronagraph attached to your telescope. This is responsible for blocking the light from the star the planet is orbiting; without it, that light will swamp any other sources in the exosolar system. Even with a good coronagraph, you need the planets to be orbiting at a significant distance from the star so that they're cleanly separated from the signal being blocked by the coronagraph.

Enlarge (credit: Bernhardt Lang)

On Friday, the US Court of Appeals for the DC Circuit denied a request to put a hold on recently formulated rules that would limit carbon emissions made by fossil fuel power plants. The request, made as part of a case that sees 25 states squaring off against the EPA, would have put the federal government's plan on hold while the case continued. Instead, the EPA will be allowed to continue the process of putting its rules into effect, and the larger case will be heard under an accelerated schedule.

Here we go again

The EPA's efforts to regulate carbon emissions from power plants go back all the way to the second Bush administration, when a group of states successfully sued the EPA to force it to regulate greenhouse gas emissions. This led to a formal endangerment finding regarding greenhouse gases during the Obama administration, something that remained unchallenged even during Donald Trump's term in office.

Obama tried to regulate emissions through the Clean Power Plan, but his second term came to an end before this plan had cleared court hurdles, allowing the Trump administration to formulate a replacement that did far less than the Clean Power Plan. This took place against a backdrop of accelerated displacement of coal by natural gas and renewables that had already surpassed the changes envisioned under the Clean Power Plan.