Hundreds of documents show how researchers failed to notify officials in California about a test of technology to block the sun’s rays — while they planned a much huger sequel. 

The upcoming interim final rule is the agency's latest use of a regulatory process usually reserved for emergencies.

Three groups filed friend of the court briefs as young climate activists seek to revive their lawsuit against EPA.

They allege that the low-carbon fuel standard is also creating "putrid odors."

The legislation covers issues including guidance documents, spending and whistleblower protections.

Multiple speakers told similar stories, some with help from a group backed by the nation’s biggest oil lobby.

Two of the world’s biggest polluters want to combat climate change — but neither wants to give an inch while doing it.

Centrist members of the European Parliament immediately condemned the far-right lawmaker’s move, which is unlikely to succeed.

Researchers say average sea temperatures may be reset higher and some ecosystems may not recover.

Soaring temperatures are making many un-air-conditioned transport links in London feel woefully unprepared for climate change.

Nature Climate Change, Published online: 28 July 2025; doi:10.1038/s41558-025-02383-1

Wind energy is helping to mitigate climate change. But now a study shows that climate change may make wind power less reliable.

Nature Climate Change, Published online: 28 July 2025; doi:10.1038/s41558-025-02391-1

Solid waste disposal is a major source of anthropogenic methane, yet estimating these emissions is difficult. Here the authors use satellite data to assess emissions from high-emitting landfills and find that transforming open sites to sanitary landfills could offer a large mitigation potential.

Nature Climate Change, Published online: 28 July 2025; doi:10.1038/s41558-025-02387-x

Prolonged low wind speeds can lead to a strong reduction in wind power generation. Here, the authors show that such wind drought events become more frequent and extended under global warming, threatening energy security in some regions.

MIT physicists have performed an idealized version of one of the most famous experiments in quantum physics. Their findings demonstrate, with atomic-level precision, the dual yet evasive nature of light. They also happen to confirm that Albert Einstein was wrong about this particular quantum scenario.

The experiment in question is the double-slit experiment, which was first performed in 1801 by the British scholar Thomas Young to show how light behaves as a wave. Today, with the formulation of quantum mechanics, the double-slit experiment is now known for its surprisingly simple demonstration of a head-scratching reality: that light exists as both a particle and a wave. Stranger still, this duality cannot be simultaneously observed. Seeing light in the form of particles instantly obscures its wave-like nature, and vice versa.

The original experiment involved shining a beam of light through two parallel slits in a screen and observing the pattern that formed on a second, faraway screen. One might expect to see two overlapping spots of light, which would imply that light exists as particles, a.k.a. photons, like paintballs that follow a direct path. But instead, the light produces alternating bright and dark stripes on the screen, in an interference pattern similar to what happens when two ripples in a pond meet. This suggests light behaves as a wave. Even weirder, when one tries to measure which slit the light is traveling through, the light suddenly behaves as particles and the interference pattern disappears.

The double-slit experiment is taught today in most high school physics classes as a simple way to illustrate the fundamental principle of quantum mechanics: that all physical objects, including light, are simultaneously particles and waves.

Nearly a century ago, the experiment was at the center of a friendly debate between physicists Albert Einstein and Niels Bohr. In 1927, Einstein argued that a photon particle should pass through just one of the two slits and in the process generate a slight force on that slit, like a bird rustling a leaf as it flies by. He proposed that one could detect such a force while also observing an interference pattern, thereby catching light’s particle and wave nature at the same time. In response, Bohr applied the quantum mechanical uncertainty principle and showed that the detection of the photon’s path would wash out the interference pattern.

Scientists have since carried out multiple versions of the double-slit experiment, and they have all, to various degrees, confirmed the validity of the quantum theory formulated by Bohr. Now, MIT physicists have performed the most “idealized” version of the double-slit experiment to date. Their version strips down the experiment to its quantum essentials. They used individual atoms as slits, and used weak beams of light so that each atom scattered at most one photon. By preparing the atoms in different quantum states, they were able to modify what information the atoms obtained about the path of the photons. The researchers thus confirmed the predictions of quantum theory: The more information was obtained about the path (i.e. the particle nature) of light, the lower the visibility of the interference pattern was. 

They demonstrated what Einstein got wrong. Whenever an atom is “rustled” by a passing photon, the wave interference is diminished.

“Einstein and Bohr would have never thought that this is possible, to perform such an experiment with single atoms and single photons,” says Wolfgang Ketterle, the John D. MacArthur Professor of Physics and leader of the MIT team. “What we have done is an idealized Gedanken experiment.”

Their results appear in the journal Physical Review Letters. Ketterle’s MIT co-authors include first author Vitaly Fedoseev, Hanzhen Lin, Yu-Kun Lu, Yoo Kyung Lee, and Jiahao Lyu, who all are affiliated with MIT’s Department of Physics, the Research Laboratory of Electronics, and the MIT-Harvard Center for Ultracold Atoms.

Cold confinement

Ketterle’s group at MIT experiments with atoms and molecules that they super-cool to temperatures just above absolute zero and arrange in configurations that they confine with laser light. Within these ultracold, carefully tuned clouds, exotic phenomena that only occur at the quantum, single-atom scale can emerge.

In a recent experiment, the team was investigating a seemingly unrelated question, studying how light scattering can reveal the properties of materials built from ultracold atoms.

“We realized we can quantify the degree to which this scattering process is like a particle or a wave, and we quickly realized we can apply this new method to realize this famous experiment in a very idealized way,” Fedoseev says.

In their new study, the team worked with more than 10,000 atoms, which they cooled to microkelvin temperatures. They used an array of laser beams to arrange the frozen atoms into an evenly spaced, crystal-like lattice configuration. In this arrangement, each atom is far enough away from any other atom that each can effectively be considered a single, isolated and identical atom. And 10,000 such atoms can produce a signal that is more easily detected, compared to a single atom or two.

The group reasoned that with this arrangement, they might shine a weak beam of light through the atoms and observe how a single photon scatters off two adjacent atoms, as a wave or a particle. This would be similar to how, in the original double-slit experiment, light passes through two slits.

“What we have done can be regarded as a new variant to the double-slit experiment,” Ketterle says. “These single atoms are like the smallest slits you could possibly build.”

Tuning fuzz

Working at the level of single photons required repeating the experiment many times and using an ultrasensitive detector to record the pattern of light scattered off the atoms. From the intensity of the detected light, the researchers could directly infer whether the light behaved as a particle or a wave.

They were particularly interested in the situation where half the photons they sent in behaved as waves, and half behaved as particles. They achieved this by using a method to tune the probability that a photon will appear as a wave versus a particle, by adjusting an atom’s “fuzziness,” or the certainty of its location. In their experiment, each of the 10,000 atoms is held in place by laser light that can be adjusted to tighten or loosen the light’s hold. The more loosely an atom is held, the fuzzier, or more “spatially extensive,” it appears. The fuzzier atom rustles more easily and records the path of the photon. Therefore, in tuning up an atom’s fuzziness, researchers can increase the probability that a photon will exhibit particle-like behavior. Their observations were in full agreement with the theoretical description.

Springs away

In their experiment, the group tested Einstein’s idea about how to detect the path of the photon. Conceptually, if each slit were cut into an extremely thin sheet of paper that was suspended in the air by a spring, a photon passing through one slit should shake the corresponding spring by a certain degree that would be a signal of the photon’s particle nature. In previous realizations of the double slit experiment, physicists have incorporated such a spring-like ingredient, and the spring played a major role in describing the photon’s dual nature.

But Ketterle and his colleagues were able to perform the experiment without the proverbial springs. The team’s cloud of atoms is initially held in place by laser light, similar to Einstein’s conception of a slit suspended by a spring. The researchers reasoned that if they were to do away with their “spring,” and observe exactly the same phenomenon, then it would show that the spring has no effect on a photon’s wave/particle duality.

This, too, was what they found. Over multiple runs, they turned off the spring-like laser holding the atoms in place and then quickly took a measurement in a millionth of a second,  before the atoms became more fuzzy and eventually fell down due to gravity. In this tiny amount of time, the atoms were effectively floating in free space. In this spring-free scenario, the team observed the same phenomenon: A photon’s wave and particle nature could not be observed simultaneously.

“In many descriptions, the springs play a major role. But we show, no, the springs do not matter here; what matters is only the fuzziness of the atoms,” Fedoseev says. “Therefore,  one has to use a more profound description, which uses quantum correlations between photons and atoms.”

The researchers note that the year 2025 has been declared by the United Nations as the International Year of Quantum Science and Technology, celebrating the formulation of quantum mechanics 100 years ago. The discussion between Bohr and Einstein about the double-slit experiment took place only two years later.

“It’s a wonderful coincidence that we could help clarify this historic controversy in the same year we celebrate quantum physics,” says co-author Lee.

This work was supported, in part, by the National Science Foundation, the U.S. Department of Defense, and the Gordon and Betty Moore Foundation.

In the past few years, governments across the world have rolled out digital identification options, and now there are efforts encouraging online companies to implement identity and age verification requirements with digital ID in mind. This blog is the first in this short series that will explain digital ID and the pending use case of age verification. The following posts will evaluate what real protections we can implement with current digital ID frameworks and discuss how better privacy and controls can keep people safer online.

Age verification measures are having a moment, with policymakers in the U.S. and around the world passing legislation mandating online services and companies to introduce technologies that require people to verify their identities to access content deemed appropriate for their age. But for most people, having physical government documentation like a driver's license, passport, or other ID is not a simple binary of having it or not. Physical ID systems involve hundreds of factors that impact their accuracy and validity, and everyday situations occur where identification attributes can change, or an ID becomes invalid or inaccurate or needs to be reissued: addresses change, driver’s licenses expire or have suspensions lifted, or temporary IDs are issued in lieu of obtaining permanent identification.  

The digital ID systems currently being introduced potentially solve some problems like identity fraud for business and government services, but leave the holder of the digital ID vulnerable to the needs of the companies collecting such information. State and federal embrace of digital ID is based on claims of faster access, fraud prevention, and convenience. But with digital ID being proposed as a means of online verification, it is just as likely to block claims of public assistance and other services as facilitate them. That’s why legal protections are as important as the digital IDs themselves. To add to this, in places that lack comprehensive data privacy legislation, verifiers are not heavily restricted in what they can and can’t ask the holder. In response, some privacy mechanisms have been suggested and few have been made mandatory, such as the promise that a feature called Zero Knowledge Proofs (ZKPs) will easily solve the privacy aspects of sharing ID attributes.

Zero Knowledge Proofs: The Good News

The biggest selling point of modern digital ID offerings, especially to those seeking to solve mass age verification, is being able to incorporate and share something called a Zero Knowledge Proof (ZKP) for a website or mobile application to verify ID information, and not have to share the ID itself or information explicitly on it. ZKPs provide a cryptographic way to not give something away, like your exact date of birth and age from your ID, instead offering a “yes-or-no” claim (like above or below 18) to a verifier requiring a legal age threshold. More specifically, two properties of ZKPs are “soundness” and “zero knowledge.” Soundness is appealing to verifiers and governments to make it hard for an ID holder to present forged information (the holder won’t know the “secret”). Zero-Knowledge can be beneficial to the holder, because they don’t have to share explicit information like a birth date, just cryptographic proof that said information exists and is valid. There have been recent announcements from major tech companies like Google who plan to integrate ZKPs for age verification and “where appropriate in other Google products”.

Zero Knowledge Proofs: The Bad News

What ZKPs don’t do is mitigate verifier abuse or limit their requests, such as over-asking for information they don’t need or limiting the number of times they request your age over time. They don’t prevent websites or applications from collecting other kinds of observable personally identifiable information like your IP address or other device information while interacting with them.

ZKPs are a great tool for sharing less data about ourselves over time or in a one time transaction. But this doesn’t do a lot about the data broker industry that already has massive, existing profiles of data on people. We understand that this was not what ZKPs for age verification were presented to solve. But it is still imperative to point out that utilizing this technology to share even more about ourselves online through mandatory age verification establishes a wider scope for sharing in an already saturated ecosystem of easily linked, existing personal information online. Going from presenting your physical ID maybe 2-3 times a week to potentially proving your age to multiple websites and apps every day online is going to render going online itself as a burden at minimum and a barrier entirely at most for those who can’t obtain an ID.

Protecting The Way Forward

Mandatory age verification takes the potential privacy benefits of mobile ID and proposed ZKPs solutions, then warps them into speech chilling mechanisms.

Until the hard questions of power imbalances for potentially abusive verifiers and prevention of phoning home to ID issuers are addressed, these systems should not be pushed forward without proper protections in place. A more private, holder-centric ID is more than just ZKPs as a catch all for privacy concerns. The case of safety online is not solved through technology alone, and involves multiple, ongoing conversations. Yes, that sounds harder to do than age checks online for everyone. Maybe, that’s why this is so tempting to implement. However, we encourage policy and law makers to look into what is best, and not what is easy.

Yet another SQUID acronym: “Stable Quasi-Isodynamic Design.” It’s a stellarator for a fusion nuclear power plant.

The Canadian government is preparing to give away Canadians’ digital lives—to U.S. police, to the Donald Trump administration, and possibly to foreign spy agencies.

Bill C-2, the so-called Strong Borders Act, is a sprawling surveillance bill with multiple privacy-invasive provisions. But the thrust is clear: it’s a roadmap to aligning Canadian surveillance with U.S. demands. 

It’s also a giveaway of Canadian constitutional rights in the name of “border security.” If passed, it will shatter privacy protections that Canadians have spent decades building. This will affect anyone using Canadian internet services, including email, cloud storage, VPNs, and messaging apps. 

A joint letter, signed by dozens of Canadian civil liberties groups and more than a hundred Canadian legal experts and academics, puts it clearly: Bill C-2 is “a multi-pronged assault on the basic human rights and freedoms Canada holds dear,” and “an enormous and unjustified expansion of power for police and CSIS to access the data, mail, and communication patterns of people across Canada.”

Setting The Stage For Cross-Border Surveillance 

Bill C-2 isn’t just a domestic surveillance bill. It’s a Trojan horse for U.S. law enforcement—quietly building the pipes to ship Canadians’ private data straight to Washington.

If Bill C-2 passes, Canadian police and spy agencies will be able to demand information about peoples’ online activities based on the low threshold of “reasonable suspicion.” Companies holding such information would have only five days to challenge an order, and blanket immunity from lawsuits if they hand over data. 

Police and CSIS, the Canadian intelligence service, will be able to find out whether you have an online account with any organization or service in Canada. They can demand to know how long you’ve had it, where you’ve logged in from, and which other services you’ve interacted with, with no warrant required.

The bill will also allow for the introduction of encryption backdoors. Forcing companies to surveil their customers is allowed under the law (see part 15), as long as these mandates don’t introduce a “systemic vulnerability”—a term the bill doesn’t even bother to define. 

The information gathered under these new powers is likely to be shared with the United States. Canada and the U.S. are currently negotiating a misguided agreement to share law enforcement information under the US CLOUD Act. 

The U.S. and U.K. put a CLOUD Act deal in place in 2020, and it hasn’t been good for users. Earlier this year, the U.K. home office ordered Apple to let it spy on users’ encrypted accounts. That security risk caused Apple to stop offering U.K. users certain advanced encryption features, , and lawmakers and officials in the United States have raised concerns that the UK’s demands might have been designed to leverage its expanded CLOUD Act powers.

If Canada moves forward with Bill C-2 and a CLOUD Act deal, American law enforcement could demand data from Canadian tech companies in secrecy—no notice to users would be required. Companies could also expect gag orders preventing them from even mentioning they have been forced to share information with US agencies.

This isn’t speculation. Earlier this month, a Canadian government official told Politico that this surveillance regime would give Canadian police “the same kind of toolkit” that their U.S. counterparts have under the PATRIOT Act and FISA. The bill allows for “technical capability orders.” Those orders mean the government can force Canadian tech companies, VPNs, cloud providers, and app developers—regardless of where in the world they are based—to build surveillance tools into their products.

Under U.S. law, non-U.S. persons have little protection from foreign surveillance. If U.S. cops want information on abortion access, gender-affirming care, or political protests happening in Canada—they’re going to get it. The data-sharing won’t necessarily be limited to the U.S., either. There’s nothing to stop authoritarian states from demanding this new trove of Canadians’ private data that will be secretly doled out by its law enforcement agencies. 

EFF joins the Canadian Civil Liberties Association, OpenMedia, researchers at Citizen Lab, and dozens of other Canadian organizations and experts in asking the Canadian federal government to withdraw Bill C-2. 

Further reading:

• Joint letter opposing Bill C-2, signed by the Canadian Civil Liberties Association, OpenMedia, Citizen Lab, and dozens of other Canadian groups 
• CCLA blog calling for withdrawal of Bill C-2
• CitizenLab (University of Toronto) blog post on Canadian CLOUD Act deal
• CitizenLab blog post on Bill C-2
• EFF one-pager and blog on problems with the CLOUD Act, published before the bill was made law in 2018

Today’s freaky LLM behavior:

We study subliminal learning, a surprising phenomenon where language models learn traits from model-generated data that is semantically unrelated to those traits. For example, a “student” model learns to prefer owls when trained on sequences of numbers generated by a “teacher” model that prefers owls. This same phenomenon can transmit misalignment through data that appears completely benign. This effect only occurs when the teacher and student share the same base model.

Interesting security implications.

I am more convinced than ever that we need serious research into ...

A warmer atmosphere can hold more water, which makes it more likely moisture-laden clouds will drop rainfall bombs when they burst.

The Upper Guadalupe River Authority tapped its $3.4 million surplus to lower property tax rates, rather than fund $1 million in flood warning upgrades.