• Signal Discovery: The LIGO, Virgo, and KAGRA detectors recorded a gravitational-wave event on August 18, 2025, involving at least one object of unusually low mass.
• Optical Identification: The Zwicky Transient Facility identified a rapidly fading red transient, later named AT2025ulz, located 1.3 billion light-years away.
• Spectral Shift: Initial red emissions from the source later brightened and shifted to blue while exhibiting hydrogen signatures, blending characteristics of both kilonovae and supernovae.
• Sub-Solar Candidates: Gravitational-wave analysis suggests one or both merging neutron stars were less massive than the Sun, a mass range not previously observed in such stellar remnants.
• Formation Theories: Researchers propose that sub-solar neutron stars may form when a rapidly spinning massive star undergoes core collapse and either splits or fragments.
• Superkilonova Hypothesis: A proposed model explains the data as a supernova that birthed twin neutron stars which subsequently merged, creating a combined eruptive event.
• Observational Challenges: Expanding debris from a concurrent supernova may obscure the specific signatures of a kilonova, complicating the confirmation of the event type.
• Future Verification: Confirmation of the superkilonova theory requires additional data from upcoming projects, including the Vera Rubin Observatory and the Nancy Roman Space Telescope.

Evidence for the possible rarity first came on August 18, 2025, when the twin detectors of LIGO in Louisiana and Washington, as well as Virgo in Italy, picked up a new gravitational-wave signal. Within minutes, the team that operates the gravitational-wave detectors (an international collaboration that also includes the organization that runs the KAGRA detector in Japan) sent an alert to the astronomical community letting them know that gravitational waves had been registered from what appeared to be a merger between two objects, with at least one of them being unusually tiny. The alert included a rough map of the source's location.

"While not as highly confident as some of our alerts, this quickly got our attention as a potentially very intriguing event candidate," says David Reitze, the executive director of LIGO and a research professor at Caltech. "We are continuing to analyze the data, and it's clear that at least one of the colliding objects is less massive than a typical neutron star."

A few hours later, the Zwicky Transient Facility (ZTF), a survey camera at Palomar Observatory, was the first to pinpoint a rapidly fading red object 1.3 billion light-years away, which is thought to have originated in the same location as the source of gravitational waves. The event, initially called ZTF 25abjmnps, was later renamed AT2025ulz by the International Astronomical Union Transient Name Server.

About a dozen other telescopes set their sights on the target to learn more, including the W. M. Keck Observatory in Hawaiʻi, the Fraunhofer telescope at the Wendelstein Observatory in Germany, and a suite of telescopes around the world that were previously part of the GROWTH (Global Relay of Observatories Watching Transients Happen) program, led by Kasliwal.

The observations confirmed that the eruption of light had faded fast and glowed at red wavelengths—just as GW170817 had done eight years earlier. In the case of the GW170817 kilonova, the red colors came from heavy elements like gold; these atoms have more electron energy levels than lighter elements, so they block blue light but let red light pass through.

Then, days after the blast, AT2025ulz started to brighten again, turn blue, and show hydrogen in its spectra—all signs of a supernova not a kilonova (specifically a "stripped-envelope core-collapse" supernova). Supernovae from distant galaxies are generally not expected to generate enough gravitational waves to be detectable by LIGO and Virgo, whereas kilonovae are. This led some astronomers to conclude that AT2025ulz was triggered by a typical ho-hum supernova and not, in fact, related to the gravitational-wave signal.

What Might Be Going On?

Kasliwal says that several clues tipped her off that something unusual had taken place. Though AT2025ulz did not resemble the classic kilonova GW170817, it also did not look like an average supernova. Additionally, the LIGO–Virgo gravitational-wave data had revealed that at least one of the neutron stars in the merger was less massive than our Sun, a hint that one or two small neutron stars might have merged to produce a kilonova.

Neutron stars are the leftover remains of massive stars that explode as supernovae. They are thought to be around the size of San Francisco (about 25 kilometers across) with masses that range from 1.2 to about three times that of our Sun. Some theorists have proposed ways in which neutron stars might be even smaller, with masses less than the Sun's, but none have been observed so far. The theorists invoke two scenarios to explain how a neutron star could be that small. In one, a rapidly spinning massive star goes supernova, then splits into two tiny, sub-solar neutron stars in a process called fission.

In the second scenario, called fragmentation, the rapidly spinning star again goes supernova, but, this time, a disk of material forms around the collapsing star. The lumpy disk material coalesces into a tiny neutron star in a manner similar to how planets form.

With LIGO and Virgo having detected at least one sub-solar neutron star, it is possible, according to theories proposed by co-author Brian Metzger of Columbia University, that two newly formed neutron stars could have spiraled together and crashed, erupting as a kilonova that sent gravitational waves rippling through the cosmos. As the kilonova churned out heavy metals, it would have initially glowed in red light as ZTF and other telescopes observed. The expanding debris from the initial supernova blast would have obscured the astronomers' view of the kilonova.

In other words, a supernova may have birthed twin baby neutron stars that then merged to make a kilonova.

"The only way theorists have come up with to birth sub-solar neutron stars is during the collapse of a very rapidly spinning star," Metzger says. "If these 'forbidden' stars pair up and merge by emitting gravitational waves, it is possible that such an event would be accompanied by a supernova rather than be seen as a bare kilonova."

But while this theory is tantalizing and interesting to consider, the research team stresses that there is not enough evidence to make firm claims.

The only way to test the superkilonovae theory is to find more. "Future kilonovae events may not look like GW170817 and may be mistaken for supernovae," Kasliwal says. "We can look for new possibilities in data like this from ZTF as well as the Vera Rubin Observatory, and upcoming projects such as NASA's Nancy Roman Space Telescope, NASA's UVEX [led by Caltech's Fiona Harrison], Caltech's Deep Synoptic Array-2000, and Caltech's Cryoscope in the Antarctic. We do not know with certainty that we found a superkilonova, but the event nevertheless is eye opening."

The paper, titled "ZTF25abjmnps (AT2025ulz) and S250818k: A Candidate Superkilonova from a Sub-threshold Sub-Solar Gravitational Wave Trigger," was funded by the Gordon and Betty Moore Foundation, the Knut and Alice Wallenberg Foundation, the National Science Foundation (NSF), the Simons Foundation, the US Department of Energy, a McWilliams Postdoctoral Fellowship, and the University of Ferrara in Italy. Other Caltech authors include Tomás Ahumada (now at NOIRLab, Chile), Viraj Karambelkar (now at Columbia University), Christoffer Fremling, Sam Rose, Kaustav Das, Tracy Chen, Nicholas Earley, Matthew Graham, George Helou, and Ashish Mahabal.

Caltech's ZTF is funded by the NSF and an international collaboration of partners. Additional support comes from the Heising-Simons Foundation and from Caltech. ZTF data are processed and archived by IPAC, an astronomy center at Caltech.

• Large-scale analysis: Examined 20 popular VPNs and 150,000 exit IPs across 137 countries.
• Exit country mismatches: 17 of 20 VPNs exit traffic from different countries than claimed.
• Overstated coverage: Providers claim 100+ countries but route to handful of US/Europe data centers.
• Routing discrepancies: Majority fail to route traffic via claimed countries.
• Provider accuracy: Only 3 of 20 VPNs verified for all announced locations.
• Virtual countries: 38 countries claimed but never observed as actual exit points.
• IP data errors: 8,000 cases where datasets misplace servers, sometimes by thousands of km.
• Report scope: Details findings, spotlights two countries, explains measurement importance, and investigation method.

In a large-scale analysis of 20 popular VPNs, IPinfo found that 17 of those VPNs exit traffic from different countries than they claim. Some claim 100+ countries, but many of them point to the same handful of physical data centers in the US or Europe.

That means the majority of VPN providers we analyzed don’t route your traffic via the countries they claim to, and they claim many more countries than they actually support. 

Analyzing over 150,000 exit IPs across 137 possible exit countries, and comparing what providers claim to what IPinfo measures, shows that:

• 17 in 20 providers had traffic exiting in a different country.
• 38 countries were “virtual-only” in our dataset (claimed by at least one provider, but never observed as the actual traffic exit country for any provider we tested).
• We were only able to verify all provider announced locations for 3 providers out of the 20.
• Across ~150,000 VPN exit IPs tested, ProbeNet, our internet measurement platform, detected roughly 8,000 cases where widely-used IP datasets placed the server in the wrong country — sometimes thousands of kilometers off.

This report walks through what we saw across VPN and IP data providers, provides a closer look at two particularly interesting countries, explores why measurement-based IP data matters if you care where your traffic really goes, and shares how we ran the investigation.

Which VPNs Matched Reality (And Which Didn’t)

Here is the overlap between the number of listed countries each VPN provider claims to offer versus the countries with real VPN traffic that we measured — lower percentages indicate providers whose claimed lists best match our data:

• Shareholder Pressure: Top Monzo investors push to remove Chair Gary Hoffman and retain outgoing CEO TS Anil.
• Key Investors: Venture firms Accel and Iconiq aim to reverse Anil’s exit over listing location disputes.
• Board Conflicts: Disagreements on growth, listing, and rivalry pace led to Anil’s October ousting.
• Leadership Transition: Anil shifts to advisory role for Diana Layfield, ex-Google executive, starting February.
• Anil’s Rationale: Memo cites Layfield’s impressiveness as reason to step aside for Monzo’s benefit.
• Company Metrics: 14 million customers, £60.4 million pretax profit, £4.5 billion valuation, potential share sale.
• Irish License: Secured full banking license from Ireland for EU expansion of accounts.
• EU Operations: Dublin HQ with 35 staff led by Michael Carney; first digital bank with Irish license, rivals Revolut.

Top Monzo shareholders are pushing to removeBloomberg Terminal Chair Gary Hoffman and convince outgoing Chief Executive Officer TS Anil to stay in post, according to the Financial Times.

Venture capital firms Accel and Iconiq are among the investors looking to reverse Anil’s exit amid disagreements about where the company should list, the FT said, citing people familiar with the matter it didn’t identify.

Monzo didn’t immediately respond to a request for comment.

The digital bank has been embroiled in boardroom disagreements around its growth and listing plans, which eventually saw the ousting of Anil in October, according to people familiar with the matter. Some felt the firm had not kept pace with its rivals around international growth, valuation, or its technology offering.

Anil announced in October he was moving into an advisory role to make way for Diana Layfield, former general manager of search international and growth at Google, who is set to take over in February. In a memo, Anil said he and the board had begun the search for a UK CEO to report to him, and met Layfield during this process.

Anil’s note to staff said Layfield was so impressive he decided to make way for her. “While it wasn’t in my plan, I knew it was an opportunity I couldn’t miss for Monzo,” he said.

Founded a decade ago, Monzo has 14 million customers. The British lender posted a pretax profit of £60.4 million ($80.6 million) for the year through March compared to £15.4 million profit in the 13 months prior. Its current valuation is £4.5 billion ($5.9 billion) and it is said to be weighing a fresh share sale, Bloomberg has previously reported.

Irish License

The latest twist comes as the fintech announces it has received an Irish banking license, a move that will allow the UK digital lender to expand into markets across the European Union.

The Central Bank of Ireland and European Central Bank have authorized the permit, according to a statement from Monzo, which will let the London-based company to offer its current and savings accounts in the EU.

The fintech first announced in June 2024 it was in the early stages of setting up an office in Ireland, and currently has around 35 staff there. Dublin becomes Monzo’s EU headquarters, and is led by former Stripe, Twitter and Google executive Michael Carney.

Monzo said it is the first digital bank to secure a full banking license from Ireland’s central bank. It will compete with Revolut, which already has more than 3 million Irish customers. Starling abandoned its Irish license push in 2022.

• Standard Model resilience: Particle physics framework withstands 2025 challenges like baryonic CP violation in LHCb decays and muon g-2 alignment.
• Neutrino masses: Tightened constraints show oscillations among three expected flavors, no novel behavior detected.
• Positive geometry theory: Proposed extension to Standard Model remains untested speculation amid rising unmotivated ideas from LLMs.
• Dark energy claims: DESI evidence for evolution at 2-sigma significance, requires combination with other data for higher levels, awaits future surveys.
• Cosmic inflation support: Predicts flatness, sub-Planck temperature, near-scale-invariant adiabatic super-horizon fluctuations confirmed.
• Early galaxies: JWST "little red dots" explained by dark matter structure formation, bursty star-formation, and supermassive black hole activity.
• Cosmic dust origins: Linked to supernovae in early massive galaxies, with GELDAs dominant in youngest epochs.
• Hubble tension persistence: Distance ladder yields 73-74 km/s/Mpc versus 67 from CMB/BAO, questioning dark energy constancy.

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Every year, scientists around the world don’t just work to enhance what we know and increase our overall body of knowledge, although that’s indeed what they wind up doing. Part of the motivation for conducting science is hope: the hope that what you’re doing, research-wise, could end up revolutionizing how we conceptualize reality. Although we’ve come so far in understanding this Universe — including what its laws and constituents are at a fundamental level, and how those fundamental components assemble to create the varied and complex reality we inhabit today — we’re certain that there’s still more to learn, as many paradoxes abound and several important puzzles remain unsolved. With each new experiment, observation, and piece of data, there’s an opportunity for scientific advancement.

All too often, however, for better or for worse, what initially seemed like:

• a mismatch between theory and observation,
• a low-significance hint that, if confirmed, would contradict our consensus picture,
• or a set of observations that supported a non-standard framework for the Universe,

appears to crumble or disappear as new, superior, and more comprehensive data was collected. Although there are always a series of sensationalistic science headlines that come out in any given year, the sober reality is that there are a great many scientific truths that continue to persist, despite their unpopularity among non-scientists, because the full suite of data overwhelmingly supports them.

In the case of the Universe, our “Standard Model” of both particle physics and cosmology remains as our consensus framework and foundation: the starting point for all the scientific endeavors we conduct today. Despite all the claims to the contrary, the Standard Model still hasn’t cracked. Here’s why.

The quarks, antiquarks, and gluons of the Standard Model have a color charge, in addition to all the other properties like mass and electric charge. All of these particles, except gluons and photons, experience the weak interaction. Only the gluons and photons are massless; everyone else, even the neutrinos, have a non-zero rest mass.

Credit: E. Siegel/Beyond the Galaxy

What you see, above, is an illustration of the Standard Model of elementary particles. Its ingredients include:

• the six quarks, each of which come in three different colors,
• and the six antiquarks, which come in three anti-colors,
• the charged leptons, the electron, muon, and tau, plus their antimatter counterparts,
• the three types of neutrino, the electron, muon, and tau, plus their antineutrino counterparts,
• the force-carrying particles: the single photon, the three heavy weak W-and-Z bosons, and the eight gluons,
• as well as the (lone) Higgs boson,

which interact through the electromagnetic, strong nuclear, and weak nuclear forces, as well as through gravity. At high energies, the electromagnetic and weak nuclear forces unify into the electroweak force.

This framework doesn’t explain everything, however. Mysteries include the origin and nature of dark matter, the nature of dark energy, the existence of more matter than antimatter (the baryogenesis puzzle), and the hierarchy problem: the lack of a mechanism for explaining the values of the rest masses of each of these particles. Going into the year, there were a variety of questions surrounding the Standard Model, and whether it would hold or be challenged by new data by the end of the year.

This 2016 reconstruction of an LHCb event shows a b-quark containing baryon that decayed, producing an s-quark containing baryon along with other mesons. With observations of sufficient numbers of these decays, the LHCb collaboration, in 2025, was able to show evidence for baryonic CP violation for the first time.

Credit: CERN/LHCb collaboration

For example, we knew that CP-violation, or a difference in the behavior of matter from antimatter when you take the mirror-image counterpart of one or the other, occurs in nature: it’s been exhibited by strange, charm, and bottom quarks in a variety of mesons. But would CP-violation, a necessary ingredient to explain baryogenesis, also appear in baryons of any type? In 2025, physicists working as part of the LHCb collaboration demonstrated that indeed, yes, baryonic CP-violation is real, finding evidence for it in the decays of two b-quark containing baryons. A potential challenge to the Standard Model rose and fell, demonstrating no need for physics beyond the Standard Model to explain the behavior of these particles.

For many years, it appeared that there was an anomaly in the magnetic moment of the muon, and that an enhanced experiment at Fermilab, the muon g – 2 experiment, would finally get us to the necessary significance to see a difference between theory and experiment. Although the experiment did indeed reach the desired precision, improvements in the theoretical methods for calculating the expected value instead led to a shift in predictions, where theory and experiment now align. It was another great opportunity for a challenge to the Standard Model, but the results instead showed that the Standard Model’s predictions indeed agreed with reality.

This image, composed of two figures from the Muon Theory Initiative’s 2025 white paper, shows at top the differences between theory and experiment depending on which leading order hadronic vacuum polarization input is used. The green results are all r-ratio (experimental data input) inputs, while the blue lines are all lattice QCD inputs. The WP25 designation reflects what’s chosen in the 2025 white paper, with the lower table showing the differences between the 2020 and the 2025 white papers.

Credit: R. Aliberti et al./Muon Theory Initiative, arXiv:2505.21476, 2025

So where do we go from here? Does this mean the Standard Model simply holds?

We’ve explored other avenues where it might not hold, and yet, our experiments just keep agreeing with what’s predicted. We narrowed down the mystery of neutrino masses to be within their tightest set of windows ever this year, and they show no hint of doing anything “novel” other than oscillating between the three known, expected flavors that exist. There are still good reasons to believe that perhaps neutrinos will someday shed some light on our current mysteries of the Universe, but that day hasn’t yet arrived here in 2025.

What about theories that go beyond the Standard Model, or extensions to it? One popular idea that gained traction in 2025 is known as positive geometry, purporting to be a path toward a theory of everything. This may turn out, someday, to be a fruitful endeavor, but for right now it’s just another idea in the sandbox: one among many that hopes to reproduce the Standard Model’s successes while explaining phenomena that the Standard Model cannot account for. However, there are very good reasons to think that, like many other theories that encapsulate but extend the Standard Model, this one will make predictions that don’t align with reality as well.

Although this picture looks very different from a conventional Feynman diagram, and also doesn’t look very much like a conventional geometric object, it encodes a framework, within the field of positive geometry, for calculating the scattering amplitude of a many-particle interacting system. This on-shell diagram helps connect the mathematics of Grassmannian manifolds with scattering amplitudes.

Credit: B. Chen et al., European Physical Journal C, 2017

Sure, there are always new theories that get proposed, but with the rise of LLMs, more and more ill-motivated theories are seeing the light of day, increasing the noise in an already noisy sea where theorists are desperately searching for even a hint of real signal. On the front of the origin of matter, our best bet for probing the unknown frontier is still to build a new, more powerful particle collider: a scenario that’s looking less and less likely as public sentiment turns away from long-term investment in fundamental science for short-sighted alternatives that may turn out to be nothing more than the latest bubble of unfulfilled promises.

Over on the cosmological side, the same set of puzzles persists:

• the origin and nature of dark matter,
• the properties and constancy (or not) of dark energy,
• and the origin of the matter-antimatter asymmetry,

plus other mysteries that have arisen purely based on observations:

• the controversy over the cosmic expansion rate,
• the origin of cosmic dust,
• the abundance and brightness of early galaxies,
• whether the untested predictions of cosmic inflation describe our reality,
• and whether dark energy is evolving or not, with this last one particularly driven by recent DESI observations.

Many have already decided for themselves — whether it’s actually true or not — that there are far too many puzzles, and far too many hints that the Standard Model is insufficient, for the consensus picture to hold.

This animation of DESI’s 3D map of the large-scale structure in the Universe, the largest such map to date, was created with the intention of studying dark energy and its possible evolution. However, although they found evidence for dark energy evolving, that’s likely due to the assumption that it’s dark energy’s evolution that’s causing the discrepancies in the data compared to our standard cosmological model. This is not necessarily the case.

Credit: DESI Collaboration/DOE/KPNO/NOIRLab/NSF/AURA/R. Proctor

But that’s not necessarily how we decide matters on scientific grounds. In particular, a large number of suggestive observations and theoretical tensions — at low significance individually — is a scoundrel’s tactic when it comes to scientific arguments. Instead, it’s the most robust data that’s most significant, and that leads us to deciding any matter that’s controversial.

For example, as far as DESI’s results are concerned, which is all about the question of whether dark energy is consistent with a cosmological constant or whether the data indicates some sort of evolution in dark energy’s properties, the significance simply isn’t there. DESI is the largest-ever deep large-scale-structure survey ever conducted, revealing galaxies, galaxy clusters, and the cosmic web more comprehensively than ever before.

And yet, on its own, the “evidence” for evolving dark energy from DESI is only about 2-σ significance, whereas 5-σ is required to announce a discovery. Only by combining it with other data sets, like the CMB and supernova data, does the significance increase, and even then, not anywhere near that 5-σ threshold. (Moreover, combination with some supernova data actually reduces the significance.) It may yet turn out that dark energy does evolve, of course, but we will have to await evidence from larger, more comprehensive surveys: from Vera Rubin, Euclid, SPHEREx, and the upcoming Nancy Roman Telescope.

In the aftermath of inflation, signatures are imprinted onto the Universe that are unmistakably inflationary in origin. While the CMB provides an early-time “snapshot” of these features, that’s just one moment in history. By probing the large variety of times/distances accessible to us throughout cosmic time, such as with large-scale structure, we can obtain information that would otherwise be obscure from any single snapshot.

Credit: Caltech/Robert Hurt(IPAC)

Many have questioned whether cosmic inflation is the correct picture for setting up and initiating the hot Big Bang, and criticisms of inflation abound, including from one of its co-founders. However, those criticisms can’t undermine inflation’s successes, including:

• its prediction of spatial flatness to a level of 99.99% or better,
• its borne-out predictions of a maximum temperature at the start of the Big Bang that’s well below the Planck scale,
• its prediction of a spectrum of seed fluctuations that’s nearly, but not quite, scale invariant,
• where the fluctuations are adiabatic and appear on super-horizon scales,

none of which can be accounted for by a hot Big Bang without an inflationary past. The evidence supporting inflation is overwhelming, and that’s why it’s just as well-accepted among professionals as dark matter or dark energy.

In the ultra-distant Universe, we’ve seen more distant galaxies than ever before, including breaking the record for the single most distant galaxy ever discovered here in 2025. Many have claimed that these early, distant galaxies, which appear in great abundance, have falsified the Standard Model of cosmology. But again, that’s not what the actual science indicates. We’ve instead learned that a combination of standard structure formation, with the key ingredient of dark matter, can indeed produce the objects we see when we see them so long as we account for the dual phenomena of bursty star-formation and brightness enhancements due to the activity of a central, supermassive black hole. These early galaxies, sometimes known as “little red dots,” are congruent with our Standard Model of cosmology.

This image shows 15 of the 341 hitherto identified “little red dot” galaxies discovered in the distant Universe by JWST. These galaxies all exhibit similar features, but only exist very early on in cosmic history; there are no known examples of such galaxies close by or at late times. All of them are quite massive, but some are compact while others are extended, and some show evidence for AGN activity while others do not.

Credit: D. Kocevski et al., Astrophysical Journal Letters accepted/arXiv:2404.03576, 2025

These early galaxies, and in particular how many of them ought to be supernova factories, can also explain the abundance and appearance of the cosmic dust that shows up early on. This cosmic dust is unevenly distributed across cosmic time, with low-dust galaxies, known as GELDAs, representing:

• 83% of all galaxies younger than 550 million years,
• 26% of galaxies between 550 million and 1.5 billion years old,
• and virtually no galaxies older than 1.5 billion years old.

Many times over the course of the year, people have come along with assertions that challenge the standard picture that dark matter exists. And yet, we know a Universe without dark matter would be very different than the one we observe, and there are several observational facts that are deep and profound that would be contrary-to-fact without the existence of dark matter.

Similarly, people have questioned whether the cosmic microwave background, or CMB, is truly of cosmic origin. But it has definitively been demonstrated that those non-cosmic origin explanations fail spectacularly for the CMB, and the fluctuations in the CMB specifically provide extraordinarily strong evidence that they are not related to the dusty, star-rich structures that form at far later periods in cosmic history.

This graph shows the angular scales of CMB fluctuations as measured by Planck, ACT, and SPT down to the smallest angular scales ever probed: about 2 arc-minutes in angular scale. For contrast, the little red dot galaxies seen are all on sub-arc-second scales, more than 100 times smaller in angular size and 10,000 times smaller in angular area than the smallest measured scales of the CMB.

Credit: E. Camphuis et al. (South Pole Telescope collaboration), arXiv:2506.20707, 2025

Meanwhile, on the black hole front, we’ve now seen hundreds of merging black holes with gravitational wave detectors such as LIGO, and those observations remain consistent with the Standard Model of cosmology; there are no indications from that data that our current picture of the Universe needs revision. And despite the assertions of famous credentialed charlatans, the newest interstellar interloper in our Solar System, Comet 3I/ATLAS, is nothing more than exactly that: an interstellar comet. It shows no signs of new physics, alien technology, unusual accelerations, or any other of the specious claims that have been associated with it.

But there is one puzzle that has remained important, and may yet truly be a hint of new physics: the Hubble tension. Despite a famed, even legendary, astronomer’s claims that we haven’t yet reached the significance to declare that the Hubble tension is a real problem for cosmology, the facts are that practically every way we have of compiling a distance ladder measurement all points toward the same conclusion: that the Universe is expanding far faster than the “early relic” methods of the CMB or BAO yield. Instead of 67 km/s/Mpc, they yield 73-74 km/s/Mpc or greater, creating a puzzle regarding the contents of the Universe and causing us to question whether dark energy is constant.

A compilation of distance ladder measurements of H0 in comparison to the Pantheon+SH0ES, where the third rung of the distance ladder is redone using various techniques. The legend shows the different techniques included in constructing this figure. For comparison, the “early relic” methods of CMB and BAO yield a value of 67 km/s/Mpc, inconsistent with distance ladder measurements.

Credit: D. Scolnic et al., RNAAS submitted/arXiv:2412.08449, 2024

Here at the end of 2025, if all you’ve done is consume popular science news, you might come away with the impression that the Standard Model — both of particle physics and of cosmology — is riddled with holes, and that many different teams of researchers have discredited it fully. That couldn’t be further from the truth; the Standard Model has repeatedly faced the most vociferous of attacks, by more who seek to knock it down, and beaten them all back with the largest suite of the highest-quality data ever collected. While puzzles certainly abound regarding what we currently understand and know, the Standard Model barely has any cracks in it at all.

Sure, we’d love to uncover the full explanation behind the Hubble tension. We’d love to know whether the DESI evidence is the harbinger of a coming revolution, or just a blip in the data. We’d love to know what the nature of dark matter and dark energy are, and how the cosmic matter-antimatter asymmetry was created. We’d love to know what the true underlying properties of neutrinos are, and whether they’re related to any or all of these puzzles. And we’d love to replace speculation about what could lie beyond the Standard Model with knowledge: with data that clearly indicates the answer.

All of that requires investing in science, in new experiments, new observatories, and in probing the frontier of fundamental physics beyond where we’ve ever probed before. Will we build new colliders, new space-based and ground-based observatories, new detectors, and the new facilities needed to answer the deepest of our questions? The option is there for us to grow our knowledge in novel ways: this year and every year to come. Whether we go down that road or not, collectively, is up to all of us.

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• Study scope: University of Limerick analysis of 570,000 people across four continents, tracking six million life-years and 43,000 deaths.
• Personality impact: Traits like neuroticism, conscientiousness, and extraversion predict mortality risk comparably to income and education.
• Neuroticism risk: One-point increase links to 3% higher death risk, especially in younger adults due to chronic stress.
• Conscientiousness benefit: One-point increase associates with 10% lower mortality risk, strongest protective effect.
• Extraversion advantage: Higher scores correlate with 3% lower death risk, notable in US and Australia.
• Neutral traits: Openness and agreeableness show little consistent link to mortality.
• Relative risks: Neuroticism elevates risk relative to lower levels, not absolute; traits influence health behaviors.
• Public health role: Personality effects match socioeconomic factors, prompting research into biological and behavioral pathways.

Your personality may influence how long you live, according to major new research that suggests certain traits can significantly raise—or lower—the risk of dying early.

The large study from the University of Limerick in Ireland found that certain personality traits—such as being anxious, highly organized, or outgoing—can strongly influence how long people live. 

In fact, these traits were just as important for predicting the risk of death as major factors like income, education and other measures of social status, say the team.

The researchers looked at decades of information from almost 570,000 people on four continents. Altogether, the data tracked nearly six million years of people’s lives and included more than 43,000 deaths—making this one of the biggest and most detailed studies yet on how personality might relate to lifespan.

Stock image of the big five personality traits model

Anxiety Tied to Higher Death Risk

Among the clearest findings was the role of neuroticism, a trait characterized by anxiety, worry and emotional instability.

Adults with higher levels of neuroticism were significantly more likely to die earlier than those with lower levels. 

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Researchers found that each one-point increase in neuroticism was associated with a three percent higher risk of death at any given time.

The link was especially strong in younger adults, suggesting that long-term stress and difficulty managing emotions can gradually wear down the body and harm health over time.

Being Organized and Outgoing May Help You Live Longer

In contrast, people who scored higher on conscientiousness—a tendency to be organized, disciplined and goal-oriented—had a substantially lower risk of death.

Each one-point increase in conscientiousness was linked to a 10 percent reduction in mortality risk, the strongest protective effect observed in the study.

Extraversion, marked by sociability and engagement with others, was also associated with longer life. 

Higher extraversion scores were linked to a three percent lower risk of death, particularly in countries such as the United States and Australia.

Not All Traits Matter Equally

The study found little to no consistent association between mortality risk and the traits of openness (curiosity and creativity) or agreeableness (cooperativeness and trust), meaning that not all traits appeared to have a baring on health and mortality. 

Meanwhile, the study's lead author Máire McGeehan, an assistant professor in psychology at the University of Limerick told Newsweek that the personality linked to higher mortality is not set in stone.

"The study looks at how those higher in neuroticism in a general population may be at higher risk of death than someone lower in neuroticism. However, it is important to say that the risk of death is relative, not absolute," McGeehan said.

Personality as a Public Health Factor

Paper author and psychologist Páraic S Ó’Súilleabháin, also of Limerick, said that the findings could reshape how researchers and policymakers think about health risks.

“Personality is a critical driver of health and longevity. It is important to emphasize that these effects are similar in size to those of commonly considered public health determinants, such as socioeconomic status,” he said.

Ó’Súilleabháin described the work as “groundbreaking,” and said that it would drive future research into how psychological traits influence biological processes and health behaviors over time.

“The information can be useful in creating awareness around choices of health behaviors and coping mechanisms, which may be contributing factors to health outcomes and a longer or shorter life," McGeehan added.

Do you have a tip on a science story that Newsweek should be covering? Do you have a question about personality traits? Let us know via science@newsweek.com.

References

McGeehan, M., Sutin, A. R., Gallagher, S., Terracciano, A., Turiano, N. A., Ahern, E., Kirwan, E. M., Luchetti, M., Graham, E. K., & O’Súilleabháin, P. S. (2025). Personality and mortality risk: A systematic review and meta-analysis of longitudinal data. Journal of Personality and Social Psychology. https://doi.org/10.1037/pspp0000577

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• Crime-poverty debate: Questions extent poverty causes crime versus shared traits like impulsiveness.
• Finnish experiment: Randomized trial gave 2,000 unemployed 560 Euros monthly for two years without job-search requirements.
• Participant profile: One-fifth in police reports as potential offenders pre-experiment.
• Crime suspicion results: Treatment group 0.5 percentage points more likely, statistically insignificant, 2% relative increase from 20% baseline.
• Effect bounds: 95% confidence intervals exclude reductions over 5% in crime suspicion probability.
• Crime categories: No offsetting effects across crime types; insignificant impacts on charges and victimization.
• US parallels: Similar null results in U.S. unconditional cash and Medicaid experiments on crime.
• Policy implication: Moderate welfare expansions unlikely to substantially control crime.

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Courtesy Martin Posdiad/Unsplash.

Certainly, crime rates are higher among the poor. But to what extent does a lack of money cause crime? To what extent do the same traits, such as impulsiveness, cause both crime and a lack of economic success? Should we focus more on addressing the economic “root causes” of crime, or more on controlling criminal behavior in and of itself?

A new working paper published through the National Bureau of Economic Research takes a fresh approach to the question. It shows that an income boost did little to reduce crime, adding fresh evidence that the poverty-crime link is not as simple as many believe.

The paper builds on a randomized trial from Finland, a nationwide experiment conducted in the late 2010s. This project gave 2,000 unemployed individuals a no-strings-attached payment of 560 Euros a month for two years—roughly equal to the minimum unemployment benefit, but with no job-search requirement and no phase-out of benefits if they started working. (If a recipient was eligible for more social benefits than that, they could still participate in programs to receive the difference.) Previous research showed it had little impact on employment, but increased disposable income about 13 percent. That was largely because participants could, in effect, keep getting their unemployment benefits even after they got a job.

Participants had high rates of involvement in crime, with a fifth appearing in police reports as potential offenders in the two years before the experiment started. Did access to the no-strings money change their trajectory?

The answer looks like no. Money quote:

In the two years following the start of the experiment, individuals in the treatment group were statistically insignificantly 0.5 percentage points more likely to be suspected of a crime (β = 0.005, standard error = 0.008), representing a 2 percent increase relative to the control group mean of 20 percent. Our estimates rule out relatively modest effects; based on our 95% confidence intervals, we can exclude the possibility that the introduction of the basic income program reduced the probability of being suspected of a crime by more than 5%.

The non-result didn’t stem from different crimes balancing each other out, as one might expect if, for example, extra money increased drinking but decreased property crime. Rather, the money just didn’t make much difference. The effect on actually being charged was also insignificant, as was the effect on victimization as opposed to perpetration.

Of course, we Americans might be careful about generalizing from this experience. What’s true in Finland might not be true here, replacing unemployment benefits with cash might have different impacts from cash alone, and perhaps we shouldn’t expect miracles from a moderate income boost. But unconditional-cash experiments in the U.S. have yielded disappointing results across many important outcomes, too, as I explained not too long ago in a City Journal piece.

Indeed, as Alex Tabarrok over at Marginal Revolution has noted, the new study pairs well with another recent one about the effect of Medicaid coverage on crime. This one, too, leverages an earlier experiment conducted for other reasons—the Oregon Health Insurance Experiment, which famously found that giving people Medicaid had little impact on their health.

The upshot: “no statistically significant impact of Medicaid coverage on criminal charges or convictions. These null effects persist for high-risk subgroups, such as those with prior criminal cases and convictions or mental health conditions.”

These new results hardly settle the entire debate over the connection between poverty and crime. But they do suggest that moderate welfare-state expansions are unlikely to have big crime-control effects.

From the Manhattan Institute

• Eric Kober offers “A Constructive Land-Use, Housing, and Economic Development Agenda for Mayor Mamdani.”

Other Work of Note

• The Council on Criminal Justice has a detailed breakdown of arrest trends since 1980, drawing on federal data but offering far more detail than the federal government’s own reports. Arrests still haven’t recovered since their plunge in 2020, and drug arrests especially are down.

• A growing conservative/liberal split in attitudes toward science.

• How much does “generational wealth” contribute to racial wealth gaps? Not much, apparently.

• “Tax Foundation modeling indicates the One Big Beautiful Bill Act (OBBBA) will boost economic growth but increase deficits, leading to record high debt in 2028 that rises to 124 percent of GDP by 2034.”

• The many effects of the minimum wage on small businesses.

• School reopenings in California appear to have reduced anxiety and depression, especially among girls.

• “This review of liquidity traps unifies three landmark economic downturns—the US Great Depression, the Great Recession, and Japan’s Long Recession—into a single analytical framework.”

• If people leave the electrical grid to rely on their own solar panels, those left behind could pay higher rates.

• New York City’s congestion pricing reduced pollution.

• How the Hays Code changed the kinds of movies Americans made.

• Is youth vaping becoming more resistant to discouragement via taxes?

• Neat study on college students finds that “relative to natural sciences, studying social sciences and humanities makes students more left-leaning, whereas studying economics and business makes them more right-leaning.”

• What’s the value of going to a public university?

• Death rates for those vaccinated against COVID are lower than those for the unvaccinated, even after adjusting for demographics and comorbidities. The big caveat is that pretty much all deaths were lower, including things like car accidents—suggesting there’s some selection bias at work and not just the direct effect of the vaccines—though the reductions in deaths from and plausibly related to COVID were much larger.

• Are the tradeoffs between accepted redistricting criteria—such as compactness and partisan fairness—overblown?

• Unsurprisingly, California’s tax on guns is passed on to consumers.

• Annual reports on college completion, concealed-carry permits, and the (ill) health of federal statistical agencies.

Have a great week, and don’t leave your Christmas shopping for the last minute!

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