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.

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Earlier this week, the US Senate passed what's being called the ADVANCE Act, for Accelerating Deployment of Versatile, Advanced Nuclear for Clean Energy. Among a number of other changes, the bill would attempt to streamline permitting for newer reactor technology and offer cash incentives for the first companies that build new plants that rely on one of a handful of different technologies. It enjoyed broad bipartisan support both in the House and Senate and now heads to President Biden for his signature.

Given Biden's penchant for promoting his bipartisan credentials, it's likely to be signed into law. But the biggest hurdles nuclear power faces are all economic, rather than regulatory, and the bill provides very little in the way of direct funding that could help overcome those barriers.

Incentives

For reasons that will be clear only to congressional staffers, the Senate version of the bill was attached to an amendment to the Federal Fire Prevention and Control Act. Nevertheless, it passed by a margin of 88-2, indicating widespread (and potentially veto-proof) support. Having passed the House already, there's nothing left but the president's signature.

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Misinformation is not a new problem, but there are plenty of indications that the advent of social media has made things worse. Academic researchers have responded by trying to understand the scope of the problem, identifying the most misinformation-filled social media networks, organized government efforts to spread false information, and even prominent individuals who are the sources of misinformation.

All of that's potentially valuable data. But it skips over another major contribution: average individuals who, for one reason or another, seem inspired to spread misinformation. A study released today looks at a large panel of Twitter accounts that are associated with US-based voters (the work was done back when X was still Twitter). It identifies a small group of misinformation superspreaders, which represent just 0.3 percent of the accounts but are responsible for sharing 80 percent of the links to fake news sites.

While you might expect these to be young, Internet-savvy individuals who automate their sharing, it turns out this population tends to be older, female, and very, very prone to clicking the "retweet" button.

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Anyone can do a simple experiment. Navigate to a search engine that offers suggested completions for what you type, and start typing "scientists believe." When I did it, I got suggestions about the origin of whales, the evolution of animals, the root cause of narcolepsy, and more. The search results contained a long list of topics, like "How scientists believe the loss of Arctic sea ice will impact US weather patterns" or "Scientists believe Moon is 40 million years older than first thought."

What do these all have in common? They're misleading, at least in terms of how most people understand the word "believe." In all these examples, scientists have become convinced via compelling evidence; these are more than just hunches or emotional compulsions. Given that difference, using "believe" isn't really an accurate description. Yet all these examples come from searching Google News, and so are likely to come from journalistic outlets that care about accuracy.

Does the difference matter? A recent study suggests that it does. People who were shown headlines that used subjective verbs like "believe" tended to view the issue being described as a matter of opinion—even if that issue was solidly grounded in fact.

Enlarge / The Velomobile Bülk, with its hood in place. Note the hood has an anti-fog covering on the visor (which is flipped up). The two bumps near the front of the hood are there to improve clearance for the cyclist's knees. (credit: JOHN TIMMER)

My brain registered that I was clearly cycling. My feet were clipped in to pedals, my legs were turning crank arms, and the arms were linked via a chain to one of the wheels. But pretty much everything else about the experience felt wrong on a fundamental, almost disturbing level.

I could produce a long list of everything my mind was struggling to deal with, but two things stand out as I think back on the experience. The first is that, with the exception of my face, I didn't feel the air flow over me as the machine surged forward down a slight slope. The second, related to the first, is that there was no indication that the surge would ever tail off if I didn't hit the brakes.

Living the dream

My visit with a velomobile was, in some ways, a chance to reconnect with a childhood dream. I've always had a fascination with vehicles that don't require fuel, like bicycles and sailboats. And during my childhood, the popular press was filled with stories about people setting human-powered speed records by putting aerodynamic fiberglass shells on recumbent bicycles. In the wake of the 1970s oil crises, I imagined a time when the roads might be filled with people cycling these pods for their commutes or covering long distances thanks to a cooler filled with drinks and snacks tucked in the back of the shell.

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Ever since the Voyager mission sent home images of Jupiter's moon Io spewing material into space, we've gradually built up a clearer picture of Io's volcanic activity. It slowly became clear that Io, which is a bit smaller than Mercury, is the most volcanically active body in the Solar System, with all that activity driven by the gravitational strain caused by Jupiter and its three other giant moons. There is so much volcanism that its surface has been completely remodeled, with no signs of impact craters.

A few more details about its violence came to light this week, with new images being released of the moon's features, including an island in a lake of lava, taken by the Juno orbiter. At the same time, imaging done using an Earth-based telescope has provided some indications that this volcanism has been reshaping Io from almost the moment it formed.

Fiery, glassy lakes

The Juno orbiter's mission is primarily focused on studying Jupiter, including the dynamics of its storms and its internal composition. But many of its orbital passes have taken it right past Io, and this week, the Jet Propulsion Laboratory released some of the best images from these flybys. They include a shot of Loki Patera, a lake of lava that has an island within it. Also featured: the impossibly sheer slopes of Io's Steeple Mountain.

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Back when scientific publications came in paper form, libraries played a key role in ensuring that knowledge didn't disappear. Copies went out to so many libraries that any failure—a publisher going bankrupt, a library getting closed—wouldn't put us at risk of losing information. But, as with anything else, scientific content has gone digital, which has changed what's involved with preservation.

Organizations have devised systems that should provide options for preserving digital material. But, according to a recently published survey, lots of digital documents aren't consistently showing up in the archives that are meant to preserve it. And that puts us at risk of losing academic research—including science paid for with taxpayer money.

Tracking down references

The work was done by Martin Eve, a developer at Crossref. That's the organization that organizes the DOI system, which provides a permanent pointer toward digital documents, including almost every scientific publication. If updates are done properly, a DOI will always resolve to a document, even if that document gets shifted to a new URL.

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Quasars initially confused astronomers when they were discovered. First identified as sources of radio-frequency radiation, later observations showed that the objects had optical counterparts that looked like stars. But the spectrum of these ostensible stars showed lots of emissions at wavelengths that didn't seem to correspond to any atoms we knew about.

Eventually, we figured out these were spectral lines of normal atoms but heavily redshifted by immense distances. This means that to appear like stars at these distances, these objects had to be brighter than an entire galaxy. Eventually, we discovered that quasars are the light produced by an actively feeding supermassive black hole at the center of a galaxy.

But finding new examples has remained difficult because, in most images, they continue to look just like stars—you still need to obtain a spectrum and figure out their distance to know you're looking at a quasar. Because of that, there might be some unusual quasars we've ignored because we didn't realize they were quasars. That's the case with an object named J0529−4351, which turned out to be the brightest quasar we've ever observed.