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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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When used to generate power or move vehicles, fossil fuels kill people. Particulates and ozone resulting from fossil fuel burning cause direct health impacts, while climate change will act indirectly. Regardless of the immediacy, premature deaths and illness prior to death are felt through lost productivity and the cost of treatments.

Typically, you see the financial impacts quantified when the EPA issues new regulations, as the health benefits of limiting pollution typically dwarf the costs of meeting new standards. But some researchers from Lawrence Berkeley National Lab have now done similar calculations—but focusing on the impact of renewable energy. Wind and solar, by displacing fossil fuel use, are acting as a form of pollution control and so should produce similar economic benefits.

Do they ever. The researchers find that, in the US, wind and solar have health and climate benefits of over $100 for every Megawatt-hour produced, for a total of a quarter-trillion dollars in just the last four years. This dwarfs the cost of the electricity they generate and the total of the subsidies they received.

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It doesn't take a lot of energy to dig up coal or pump oil from the ground. By contrast, most renewable sources of energy involve obtaining and refining resources, sophisticated manufacturing, and installation. So, at first glance, when it comes to the energy used to get more energy—the energy return on investment—fossil fuels seem like a clear winner. That has led some to argue that transitioning to renewables will create an overall drop in net energy production, which nobody is interested in seeing.

A new study by researchers at the UK's University of Leeds, however, suggests that this isn't a concern at all—in most countries, renewables already produce more net energy than the fossil fuels they're displacing. The key to understanding why is that it's much easier to do useful things with electricity than it is with a hunk of coal or a glob of crude oil.

Energy efficiency and utility

The basic idea behind the new work is that while it's energetically cheap to extract fossil fuels, the stuff that comes out of the ground isn't ready to be put to use. There are energetic costs to making it into a useful form and transporting it to where it's needed, and then there is lost energy when it's being put to use. That's especially notable for uses like internal combustion engines, where significantly less than half of the energy available in gasoline actually gets converted into motion.

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If things work out as hoped, brain implants will ultimately restore communication for those who have become paralyzed due to injury or disease. But we're a long way from that future, and the implants are currently limited to testing in clinical trials.

One of those clinical trials, based at the University of California, San Francisco, has now inadvertently revealed something about how the brain handles language, because one of the patients enrolled in the trial was bilingual, using English and Spanish. By tracking activity in the area of the brain where the intention to speak gets translated into control over the vocal tract, researchers found that both languages produce consistent signals in this area, so training the system to pick up English phrases would help improve its recognition of Spanish.

Making some noise

Understanding bilingualism is obviously useful for understanding how the brain handles language in general. The new paper describing the work also points out that restoring communications in multiple languages should be a goal for restoring communications to people. Bilingual people will often change languages based on different social situations or sometimes do so within a sentence in order to express themselves more clearly. They often describe bilingual abilities as a key component of their personalities.

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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 / Top: a look through the past 2,000 years of summertime temperatures, showing that 2023 is considerably warmer than anything earlier. Bottom: a bell curve of the typical temperatures, showing that the hot outliers are all recent years. (credit: Esper, Torbenson, and Büntgen)

Starting in June of last year, global temperatures went from very hot to extreme. Every single month since June, the globe has experienced the hottest temperatures for that month on record—that's 11 months in a row now, enough to ensure that 2023 was the hottest year on record, and 2024 will likely be similarly extreme.

There's been nothing like this in the temperature record, and it acts as an unmistakable indication of human-driven warming. But how unusual is that warming compared to what nature has thrown at us in the past? While it's not possible to provide a comprehensive answer to that question, three European researchers (Jan Esper, Max Torbenson, and Ulf Büntgen) have provided a partial answer: the Northern Hemisphere hasn't seen anything like this in over 2,000 years.

Tracking past temperatures

Current temperature records are based on a global network of data-gathering hardware. But, as you move back in time, gaps in that network go from rare to ever more common. Moving backward from 1900, the network shrinks to just a few dozen land-based thermometers, almost all of them in Europe.

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.