How Common Are Hallucinated Citations In Academic Papers?

Academic papers written with AI that contain hallucinated citations are on the rise.

Large language models (LLMs) are known to generate plausible but false information across a wide range of contexts, yet the real-world magnitude and consequences of this hallucination problem remain poorly understood. 

Here we leverage a uniquely verifiable object - scientific citations - to audit 111 million references across 2.5 million papers in arXiv, bioRxiv, SSRN, and PubMed Central. We find a sharp rise in non-existent references following widespread LLM adoption, with a conservative estimate of 146,932 hallucinated citations in 2025 alone. 

These errors are diffusely embedded across many papers but especially pronounced in fields with rapid AI uptake, in manuscripts with linguistic signatures of AI-assisted writing, and among small and early-career author teams. At the same time, hallucinated references disproportionately assign credit to already prominent and male scholars, suggesting that LLM-generated errors may reinforce existing inequities in scientific recognition. Preprint moderation and journal publication processes capture only a fraction of these errors, suggesting that the spread of hallucinated content has outpaced existing safeguards. Together, these findings demonstrate that LLM hallucinations are infiltrating knowledge production at scale, threatening both the reliability and equity of future scientific discovery as human and AI systems draw on the existing literature.

Zhenyue Zhao, Yihe Wang, Toby Stuart, Mathijs De Vaan, Paul Ginsparg, Yian Yin, "LLM hallucinations in the wild: Large-scale evidence from non-existent citations" arXiv:2605.07723 (May 8, 2026).

arXiv Is Moving

A few weeks ago, arXiv.org announced that it will be leaving Cornell, the university that currently manages it, and establishing its own nonprofit.

From 4 gravitons.

An Unreview

What makes this paper especially notable is not its content per se but the concept of an "unreview", which potentially has broad interdisciplinary applications.

Accreting white dwarfs (AWDs) are among the best natural laboratories for understanding disk accretion. Their proximity, brightness, and purely classical nature make them ideal systems in which to probe the fundamental physics that governs the transport of angular momentum, the generation of outflows, and the coupling between disks, magnetospheres, and accretors. Yet despite decades of study, many critical questions remain unresolved. 

In this ``unreview'', we therefore focus not on what is known, but on what is unknown. 

What drives viscosity and sustains accretion in largely neutral disks? How are powerful winds launched, and how do they feed back on the disk and binary evolution? Why do so many systems show persistent retrograde precession, and what drives bursts in magnetic AWDs? 

By identifying these open problems -- and suggesting ways to resolve them -- we aim to motivate new observational, numerical, and theoretical efforts that will advance our understanding of accretion physics across all mass scales, from white dwarfs to black holes.

Simone Scaringi, Christian Knigge, Domitilla de Martino, "Accreting White Dwarfs: An Unreview" arXiv:2603.10150 (March 10, 2026) (Accepted in Space Science Reviews).

Also notable is a paper demonstrating that a twenty times faster method of computing big data in cosmology is indistinguishable in its results from a more conventional method of doing so, despite the fact that the faster method isn't obviously theoretically rigorous and sound (because it uses linear rather than non-linear mathematical methods).

There is also a new paper replicating a result of a 2026 paper finding MOND-like effects in wide binaries using a modestly different analysis method.

The Big Picture In Astrophysics Research

It is more statistical than an analytic description of the most important scientific advances, but it is still a notable overview. Certainly, there is no room to dispute that there has been a surge in astrophysics papers.

Over the past few years, Astrophysics has experienced an unprecedented increase in research output, as is evident from the year-over-year increase in the number of research papers put onto the arXiv. As a result, keeping up with progress happening outside our respective sub-fields can be exhausting. While it is impossible to be informed on every single aspect of every sub-field, this paper aims to be the next best thing. 

We present a summary of statistics for every paper uploaded onto the Astrophysics arXiv over the past year - 2025. We analyse a host of metadata ranging from simple metrics like the number of pages and the most used keywords, as well as deeper, more interesting statistics like the distribution of journals to which papers are submitted, the most used telescopes, the most studied astrophysical objects including GW, GRB, FRB events, exoplanets and much more. We also indexed the authors' affiliations to put into context the global distribution of research and collaboration. 

Combining this data with the citation information of each paper allows us to understand how influential different papers have been on the progress of the field this year. Overall, these statistics highlight the general current state of the field, the hot topics people are working on and the different research communities across the globe and how they function. 

We also delve into the costs involved in publications and what it means for the community. We hope that this is helpful for both students and professionals alike to adapt their current trajectories to better benefit the field.

Rommulus Francis Lewis, Hetansh Shah, Amruth Alfred, "Astrophysics Wrapped 2025: Year-in-Review of Every Astrophysics arXiv Paper from 2025" arXiv:2602.12303 (February 11, 2026).

My name is Bond. Molecular Bond.

Ian Fleming*, "Molecular Orbitals and Organic Chemical Reactions" (2009).

*not the James Bond author.

2801 Posts (And A Question)

My previous post was number 2800 at this blog, which is one week short of 14 years old today, so I'm averaging just slightly over 200 posts a year, which is not quite 4 posts a week.

The question, which I'm musing over and want to post now so I don't let it slip my mind, because it's interesting (even though I'm not yet ready to answer it) is:

What would be the most shocking and revolutionary scientific discovery you can think of that is possible, but currently seems unlikely to you?

To be clear, I mean scientific discoveries and not technological break throughs with existing scientific knowledge or highly foreseeable and expected new scientific discoveries. So, for example, vast improvements in quantum computing, or discovering a cure for some major kind of cancer, don't count.

Also, the answer to this question has a subjective element. 

For example, the majority view among astrophysicists is that some form of dark matter particle which is beyond the Standard Model exists, so discovering one wouldn't be all that surprising to them. But this would be much more surprising to me, as I believe that dark matter phenomena are much more likely to have a cause rooted in some sort of gravitational effect.

Perhaps the most shocking discovery, to me, in the last few years, has been the discovery of human footprints in New Mexico dated to 22,000 years ago (well inland, close in time to but prior to the Last Glacial Maximum that was a barrier to settlement further south, and 8,000 years earlier that the southern migration of the primary human population of the Americas). These Progenitors, however, failed to thrive and left very few definitive traces of their presence.

Feel free to add you own answers to this question in the comments.

A Notable Life In Quantum Physics

Chien-Shiung Wu was one of the pioneers of quantum mechanics and high energy physics, and was a female Chinese physicists in an era where women still made up only a tiny percentage of scientists in the field. 

If something remembers you with a speech like this, one hundred and ten years after you were born, when you have long passed away, then you did something right in life.

In 1950, Chien-Shiung Wu and her student published a coincidence experiment on entangled photon pairs that were created in electron-positron annihilation. This experiment precisely verified the prediction of quantum electrodynamics. 

Additionally, it was also the first instance of a precisely controlled quantum entangled state of spatially separated particles, although Wu did not know about this at the time. 

In 1956, Wu initiated and led the so-called Wu experiment, which discovered parity nonconservation, becoming one of the greatest experiments of the 20th century. 

As Chen Ning Yang said, Wu's experiments were well known for their precision and accuracy. Experimental precision and accuracy manifested Wu's scientific spirit, which we investigate here in some detail. 

Yu Shi, "Scientific Spirit of Chien-Shiung Wu: From Quantum Entanglement to Parity Nonconservation" arXiv:2504.16978 (May 31, 2022) (This paper is the translated transcript of the speech the author made at the International Symposium Commemorating the 110th Anniversary of the Birth of Chien-Shiung Wu, on May 31, 2022 in Chinese. The above abstract is the translation of the original abstract of the speech.)

She earned her undergraduate degree in physics (which had a thesis requirement at the time) in China in 1934, prior to the Maoist Revolution, and earned a PhD working under a professor only three years older than her who had studied under Madame Curie, and under the first female PhD in Physics in China, who earned that degree at the University of Michigan (where I also earned my graduate degree). Wu earned her PhD at the University of California at Berkley in 1940 (thirty years before my father earned his PhD at Stanford).

Wu was admitted by the University of Michigan to study at her own expense, and was financially supported by her uncle. On her way to Michigan, Wu visited Berkeley, where she was so impressed, especially by Ernest O. Lawrence’s cyclotron, that she wanted to stay in Berkeley. The cyclotron had been invented by Lawrence, so it was an ideal place for studying physics. Another important factor that influenced Wu’s decision was that she cared a lot about gender equality, and there was gender discrimination at the University of Michigan. In addition, there were a lot of Chinese students at the University of Michigan at the time, and Wu didn’t want her socializing be dominated by fellow Chinese students. So she stayed in Berkeley. Her decision reflected her devotion to physics as a woman.

She then taught at Smith (from which my sister-in-law graduated), and then Princeton, and then she worked at Columbia University as part of the Manhattan Project. 

She was highly productive (publishing more than fifty papers in the early 1950s when a huge share of U.S. women were homemakers in the Baby Boom), and her early post-war research agenda involved the verification of Fermi’s theory of β decay.

Chien-Shiung Wu served as the President of the American Physical Society from 1975 to 1976.

James W. Cronin, who won the 1980 Nobel Prize for his discovery of charge conjugation-parity (CP) nonconservation, once said, “The great discovery of Chien-Shiung Wu started the golden age of particle physics.” 

She continued to publish through at least 1980, and died in February of 1997. The author of the paper had met her.

Current LHC SUSY Exclusions

Supersymmetry, and its further elaboration, string theory, have turned out to be the biggest wrong turns in the history of high energy physics. They produced a few mathematical insights and better understandings of some deeper points about the Standard Model of Particle Physics along the half century journey, but ultimately these theories and these lines of inquiry were dead ends.  These theories continue to receive academic and experimental attention now, mostly because so many tenured physicists built their careers on these theories before their flaws became apparent.

(In due time, I expect that concepts like dark matter, dark energy, and cosmological inflation in astrophysics will similarly be found to have been plausible, but ultimately mistaken wrong turns, as well. Indeed, supersymmetry was originally one of several important reasons that dark matter particles received wider popularity as an explanation of dark matter phenomena and that the LambdaCDM model of cosmology gained wide initial acceptance, because it provided dark matter particle candidates that were well-motivated at the time, in roughly the right quantities in a thermal freeze out scenario in what was called the "WIMP miracle" until observational and experimental evidence ruled it out.)   

Supersymmetry is a theoretical framework in physics that suggests the existence of a symmetry between particles with integer spin (bosons) and particles with half-integer spin (fermions). It proposes that for every known particle, there exists a partner particle with different spin properties. There have been multiple experiments on supersymmetry that have failed to provide evidence that it exists in nature. If evidence is found, supersymmetry could help explain certain phenomena, such as the nature of dark matter and the hierarchy problem in particle physics. . . . 

There is no experimental evidence that either supersymmetry or misaligned supersymmetry holds in our universe, and many physicists have moved on from supersymmetry and string theory entirely due to the non-detection of supersymmetry at the LHC.

From Wikipedia (the emphasis in bold is mine). The chart below related to the theory sets forth the components of supersymmetry in one of its simpler forms (placing some of the terms used in the material quoted below in a clearer context):

A preprint of a commissioned review article for the Encyclopedia for Particle Physics, submitted on May 3, 2025 by Hyun Min Lee, entitled "Supersymmetry and LHC era" updates the experimental bounds on supersymmetry (SUSY) theories based upon the Large Hadron Collider (LHC) data. 

The author tries to paint this limitations in a positive light for supersymmetry, but the hard basic facts are that supersymmetry is now all but dead as a viable explanation of the real world, and that supersymmetric particles (a.k.a. "sparticles") don't exist.

Some of articles' more specific conclusions are as follows:

[T]he gluino masses up to about 2.4 TeV and the squark masses up to about 1.8 TeV have been ruled out by ATLAS. Similar limits from CMS can be also found. . . . stop masses up to about 1250 GeV have been ruled out from ATLAS data and there are similar bounds on the stop mass from CMS. . . . the mass ranges up to about 700 GeV for sleptons and about 1200 GeV for chargino or heavier neutralino have been excluded.

Some supersymmetric models are inconsistent with the current W boson mass (apart from the anomalous and deeply flawed CDFII measurement that is 7 sigma from the global average measurement of more recent and more precise experiments and from the other experiment at Tevatron). For example, this constrains the slepton mass.

More supersymmetric models are inconsistent with the agreement between the experimental value of muon g-2 and the Lattice QCD prediction for its value (rather than the flawed "white paper" value which is 5.2 sigma from the experimental value). The white paper estimate of the muon g-2 deviation from the Standard Model expectation is about 2.5 ± 0.5 * 10^-9, while the Lattice QCD prediction which is confirmed by more recent experimental date is closer to 0.5 * 10^ -9. The paper examine several supersymmetric particle parameter models at values from 1.56 to 2.24 * 10^-9 noting that:

In the left of Fig.3, we present three benchmark models which are consistent with the muon g−2 anomaly within1σ (Model II and III) or 2σ (Mode I) in general gauge mediation.We listed the masses for electroweak superpartners in general gauge mediation and the predictions for ∆aµ and ∆MW. In particular, ModelIII is also consistent with the W boson mass measured by CDFII within1σ. 

In the right plot of Fig.3, we also show the general independent mass parameters for superpartners, namely, m˜ qL ≃m˜ uR ≃m˜ dR, M1, M2, M3, m˜ lL and m˜ eR. 

The paper doesn't even try to devise a set of parameters of supersymmetry with the much smaller muon g-2 anomaly that the overwhelming evidence suggests is actually the case when the Standard Model expectation is calculated correctly. It does note, however that:

There are two typos [sic] of supersymmetric interactions relevant for the muon g−2. One Yukawa type interaction of the muon is to a neutral scalar ϕ with mass mϕ and a charged fermion F with charge −1 and mass mF . . . . Another Yukawa type interaction of the muon is to a charged scalar χ with charge −1 and mass mχ and a neutral fermion λ with mass mλ[.]

So, given the actual muon g-2 consistency between experiment and the predicted Standard Model value, the mass of the superpartners on the order of 400 GeV in the Model I scenario would have to be much higher. It would probably have to be at least in the 800s GeV, if not more, as estimated by me using linear interpolation from the other models in what is actually a non-linear relationship that probably sets the lower bounds even higher.

We comment on the dark matter candidates and collider signatures with electroweak superpartners in the benchmark models. 

In Model I, the neutralino is the LSP, so it can be a dark matter candidate. In this case, due to small splitting between the slepton masses and the neutralino mass, the decay products of the sleptons may be composed of soft jets or leptons (See the left plot in Fig. 4). If the gravitino is lighter than the neutralino, then it can be a dark matter candidate, but displaced decays of the neutralino can lead to distinct signatures at the LHC (See the right plot in Fig. 4 for the results from ATLAS). 

On the other hand, in Model II and III, smuon or sneutrino is the LSP, so there is no dark matter candidate within the MSSM. However, if the gravitino is lighter than the sleptons, the MSSM LSP is long-lived, decaying into a pair of the gravitino and charged leptons(neutrinos) at the displaced vertex from the production point (See the right plot in Fig. 5 for the results from ATLAS). In all the benchmark models, the heavier neutralinos or charginos have been searched for from their prompt decays, as shown in the left plot of Fig. 5.

The paper doesn't connect the dots, but because we know from direct dark matter detection experiments that there is no supersymmetric particle consistent with being a dark matter particle in anything approximating these mass ranges, that the paper's Model I's lightest supersymmetric particle (LSP) cannot be a dark matter candidate.

Proton decay also rules out much more of the SUSY parameter space if one doesn't resort to Baroque convolutions in the theory to suppress it:

In the minimal SU(5) unification with TeV-scale masses for superpartners, the dimension-5 operators generated at the mass scale of the colored Higgisnos are problematic for the proton lifetime. Even in the scenarios with split masses between colored and non-colored superpartners in general gauge mediation, the problem remains because of a large decay rate of the proton coming from the stop, the light stau and the Higgsinos in loops. However, the problem of the proton lifetime can be solved when the model is embedded in the orbifold GUTs where the Higgsino wavefunctions get suppressed at the orbifold fixed point, so do the dimension-5 operators for the proton decays.

Finally, not to put too fine a point on it, but there is absolute zero positive experimental evidence for supersymmetry or superpartners, despite the fact that looking for them was what the LHC was optimized to do. The exclusions are only as low as they are due to the constraints of the instrumentation to explore higher energies.

The bottom line is that supersymmetry is absent up to the TeV level, and the non-detection of proton decay, the lack of a muon g-2 anomaly, and the W boson mass all disfavor it at masses for superpartners at least up to the 10s of TeVs level.

Supersymmetry doesn't address the hierarchy problem is was devised to address, doesn't provide a dark matter candidate, doesn't explain any well established anomalies in the observational or experimental data. In general, supersymmetry no longer well-motivated as a beyond the Standard Model theory.

Moreover, because supersymmetry is a low energy approximation of the lion's share of string theories given serious examination by theoretical physicists, these experimental bounds also strongly disfavor string theory.

Of course, supersymmetry advocates and string theory advocates can try, as they have many times  over the last fifty years or so since it was proposed in the late 1960s and early 1970s, to move the goalposts of their predictions for its parameters "just around the corner" from the experimental limits that rule out or strongly disfavor it to values that can't yet be ruled out, even though these parameter values would no longer address anything that motivated this theoretical approach in the first place. 

But, increasingly, "just around the corner" means energy scales that cannot be reached even at the next generation of particle collider, but which might be reached at the next generation particle collider after that one, maybe several decades in the future.

Footnote

Another preprint today looks at dark matter particle candidates whose properties are strongly fixed by existing measurements in an SU(6) Grand Unified Theory (GUT) model. 

The allowed parameters for these dark matter candidates, however, are ruled out by astrophysics observations (the single digit plus TeV mass candidates are too massive to be directly ruled out by direct dark matter experiments).

Finally, yet another preprint today also considers a two component dark matter particle model suggested by a different GUT, which is ruled out by direct dark matter detection experiments, unless the GUT is twisted in a manner specifically designed to overcome this problem that otherwise has no observational or theoretical motivation. This elaborated version of the GUT does create a theoretical basis for neutrino mass, but also establishes a dark matter candidate that is ruled out by astronomy evidence, even though it isn't ruled out by direct dark matter detection experiments or high energy physics experiments.

John Hawks On Scientific Consensus

John Hawks, an anthropologist who specializes in archaic hominins, considers at his blog what the term "scientific consensus" means in reaction to an article in the peer reviewed scientific journal Science. He begins as follows:

In an editorial in this week's Science, the journal's editor Holden Thorp develops an argument that the notion of “scientific consensus” has confused public discussion of science. In Thorp's view, the public misunderstands “consensus” as something like the result of an opinion poll. He cites the communication researcher Kathleen Hall Jamieson, who observes that arguments invoking “consensus” are easy for opponents to discredit merely by finding some scientists who disagree.

Thorp notes that what scientists mean by “consensus” is much deeper than a popularity contest. He describes it as “a process in which evidence from independent lines of inquiry leads collectively toward the same conclusion.” Leaning into this idea, Thorp argues that policymakers should stop talking about “scientific consensus” and instead use a different term: “convergence of evidence”.

It would be a big move for a magazine representing the entire breadth of American science to reject the idea of scientific consensus.

For the last twenty years the idea of “scientific consensus” has been widely adopted by scientific organizations and policymakers, especially applied to politically contentious topics such as climate change, vaccine hesitancy, and COVID-19 response. Many organizations shifted their policy advocacy by issuing statements reflecting the consensus of their members. Science itself helped launch this era with the publication of Naomi Oreskes' 2004 article, “The Scientific Consensus on Climate Change”. This article recounted the number of organizations representing scientists that had issued statements or policy documents about the evidence for human-induced climate change.

The purpose of such statements was to counter public perceptions that there might be significant scientific disagreement about climate change.

There use of the term has grown steadily since the late 1960s (image from the linked blog entry):

Another chart in the blog post notes that use of the term "convergence of evidence" peaked in the 1950s and that "scientific consensus" overtook it in frequency of use around 1985.

Hawks argues that there is also a place for the concept of a consilience of evidence:

The idea was formulated by the nineteenth-century philosopher William Whewell, who also coined the word scientist. Whewell wanted to understand how observations give rise to theories. His idea was that the induction of a hypothesis or theory from observations requires another step, a step in which evidence developed by other means of observation must also show consistency with the same theory or hypothesis. He used the term “consilience” for this matching of evidence of different kinds.

Michael Ruse noted Charles Darwin's work as a hallmark of the consilience approach. Darwin brought together evidence from entirely different fields of inquiry: animal and plant breeding, geology, natural history, biogeography, sociology, and many others. He had a remarkable ability to answer questions in one field by examining data in another field entirely. The ability to bring together observations that seem disconnected from each other, explain all of them with one unifying explanation is a powerful mode of scientific thinking.

Consilience of evidence also helps to answer criticism that scientists are closing off debate by excluding ideas that do not fit within their disciplinary boundaries. Where “convergence of evidence” may seem inward-facing, confined to a single research tradition, consilience is explicitly outward-reaching. It requires translation and integration across disciplinary boundaries and sometimes even across different ways of knowing.

I'm skeptical of both the "convergence of evidence" question, which has many of the same problems, and the "consilience of evidence" phrase, which is just beyond the vocabulary of most of the people for whom the rhetoric in which the term might be used is directed.

But the deeper and ultimate question is how to draw the line between what is settled and accepted science, to which any legitimate future challenge has not yet manifested, and scientific ideas which remain the subject of controversy among scientists. 

On one hand, one doesn't really want to adopt the standard of a "hecklers veto" which suggests that a crackpot with weak methodology or methods that cause other scientists inclined to be sympathetic to not take the crackpot seriously, is sufficient to upset a scientific consensus. But on the other hand, one doesn't want to leave the misimpression that scientific truth is a popularity contest or a matter of democratic decision-making, or that the authority and prestige of individual scientists holding a scientific opinion is more important than the evidence and reasoning supporting their opinions. 

When there are two well-reasoned theories advanced by people who are behaving like genuine scientists that are each supported by evidence that doesn't conclusively disprove the alternative, there is no scientific consensus on which one is correct (although there are still many crackpot theories that are definitively rejected by the scientific consensus even at times where there is not a scientific consensus around more than one disputed possible scientific truth to explain the world).

Making these distinctions at a vague, common sense level, in actual real world cases, usually isn't that hard. But putting into words a rule that puts some cases on one side of the line, and other cases on the other side of the line, can be challenging.

Today's Notable arXiv Papers

Astrophysicists were playful this year. HEP physicists weren't feeling the love. 

Since their domestication at the dawn of civilization, cats have been known for their uncanny ability to seemingly defy gravity. We conjecture that this innate ability of cats is real: uniquely in the animal kingdom, felis catus, possibly along with a few closely related species, are indeed capable of manipulating their passive gravitational mass. We explore this idea in the context of both general relativity and quantum physics. We reach the intriguing conclusion that a close study of the behavior of cats in a gravitational field might shed light not only on the mechanism of neutrino mass mixing but perhaps even on the most fundamental question in theoretical physics: a satisfactory unification of the theory of gravitation and quantum field theory.

Viktor T. Toth, "Feline gravity manipulation" arXiv:2503.22919 (April 1, 2025).

In the big data era of Astrophysics, the improvement of visualization techniques can greatly enhance the ability to identify and interpret key features in complex datasets. This aspect of data analysis will become even more relevant in the near future, with the expected growth of data volumes. With our studies, we aim to drive progress in this field and inspire further research. We present the second release of pastamarkers, a Python-based matplotlib package that we initially presented last year. In this new release we focus on big data visualization and update the content of our first release. We find that analyzing complex problems and mining large data sets becomes significantly more intuitive and engaging when using the familiar and appetizing colors of pasta sauces instead of traditional colormaps

PASTA Collaboration, "pastamarkers 2: pasta sauce colormaps for your flavorful results" arXiv:2503.23126 (April 1, 2025).

Any permutation-invariant function of data points r⃗ i can be written in the form ρ(∑iϕ(r⃗ i)) for suitable functions ρ and ϕ. This form - known in the machine-learning literature as Deep Sets - also generates a map-reduce algorithm. The area of a triangle is a permutation-invariant function of the locations r⃗ i of the three corners 1≤i≤3. We find the polynomial formula for the area of a triangle that is explicitly in Deep Sets form. This project was motivated by questions about the fundamental computational complexity of n-point statistics in cosmology; that said, no insights of any kind were gained from these results.

Connor Hainje, David W. Hogg, "A formula for the area of a triangle: Useless, but explicitly in Deep Sets form" arXiv:2503.22786 (April 1, 2025).

Johannes Kepler's attempt to explain the arrangement of the six innermost planets of the Solar System using his Platonic Solid Model-which postulates that planetary orbits are nested within the five Platonic solids-was ultimately unsuccessful. However, while his model failed to describe our own planetary system, Kepler was remarkably prescient in hypothesizing the existence of exoplanetary systems that might conform to this geometric framework. In this study, we analyze all known multiple exoplanet systems containing three to six planets and identify those that best match the Keplerian Platonic model. Using a semi-major-axis (SMA) ratio metric defined as the sum of squared differences between observed and theoretical semi-major-axis ratios, we find that the most well-matched three-, four-, five-, and six-planet exoplanetary systems exhibit significantly lower discrepancy values (4.38×10−6,1.05×10−2,8.21×10−2, and 2.43×10−1, respectively) compared to the inner six planets of the Solar System at 12.68. These results demonstrate that Kepler's Platonic Model is applicable to certain exoplanetary systems, suggesting that while the Solar System does not adhere to this idealized structure, other planetary systems may be governed by underlying geometric and mathematical principles akin to Kepler's vision. This study highlights the special nature of these exoplanetary systems and their potential alignment with the Platonic five-element framework.

Ji Wang, "Kepler's Platonic Model and Its Application to Exoplanetary Systems" arXiv:2503.22793 (April 1, 2025).

This paper explores an unexpected yet compelling parallel between the evolution of the universe, as described by cosmological eras, and the artistic evolution of Taylor Swift, delineated by her distinct album eras. By mapping key characteristics and transitions in the universe's history to corresponding themes and milestones in Swift's career, I offer a novel perspective on both. I culminate with predictions for Swift's future work and dare to ask a question of cosmic importance: Could Taylor Swift's thirteenth album hold the secret to the universe's ultimate destiny?

Jane C. Bright, "The Eras Tour: Mapping the Eras of Taylor Swift to the Cosmological Eras of the Universe" arXiv:2503.22795 (April 1, 2025).

Understanding our place in the universe is an eternal quest. Through the analysis of the 3D structures of 66 nearby open clusters using Gaia DR3 data, we discovered an intriguing pattern: most clusters show their elongation directions pointing at the Sun, suggesting that the Solar System might just be the universe's favorite spot, a cosmic feng shui hotspot! This surprising result hints at a subtle blend of geometry and geomancy.

Lu Li, Zhengyi Shao, "On the structure of open clusters: geometric vs geomantic" arXiv:2503.22800 (April 1, 2025).

We present a novel and somewhat whimsical approach to pulsar hotspot modeling by drawing inspiration from the iconic one-eyed monster, Mike Wazowski, from Monsters, Inc. Utilizing X-ray high-quality timing data from NICER, we apply a Bayesian inference framework to model the X-ray pulse profile of PSR J0437--4715. Our analysis employs a Wazowski Configuration (WC) in which the conventional hotspot parametrization is replaced with a predefined image template, whose redness and size are adjusted to mimic temperature variations. The results reveal a configuration where two hotspots--one brighter and smaller in the north represents the energetic ``University time Wazowski", and one larger yet cooler in the south represents the ``Monster, Inc. time Wazowski"--combine to produce the observed X-ray pulse profile. These findings not only demonstrate the sensitivity of pulse profile modeling to hotspot morphology but also open up the intriguing possibility that the X-ray emission of some pulsars may be interpreted as a cosmic homage to our favorite animated character.

Chun Huang, "The Cosmic One-Eyed Smile: Revealing the Hidden Face of Mike Wazowski" arXiv:2503.22914 (April 1, 2025) (Submitting to Monster University Journal).

Cookies are enjoyed best when they are both crispy and soft. I investigate in which proportion the cookies are crispy and soft, and disentangle whether it makes them biscuits, cakes, or none of the above. I baked cookies for colleagues at KTH, Stockholm, and University of Geneva, Switzerland, adopting my mum's mum's mum's etc. recipe. I created a dedicated survey for my colleagues with three well-selected questions to answer while eating one cookie. The weighted-average mean of the crispiness and softness, weighted by the respective enjoyment of the cookie, over the whole population amount to 7.0 +/- 1.1 and 5.3 +/- 1.4, respectively. The enjoyment of the cookies amounts to 9.1 +/- 2.3. People like (my) cookies, and cookies are neither cakes, nor biscuits, they are just... cookies!

Sophie Rosu, "All about Cookies: The perfect compromise between softness and crispiness" arXiv:2503.23114 (April 1, 2025).

Catsteroseismology, or asterocatsmology, is an unexplored area of observational and theoretical research that proposes to use purr-mode oscillations to study the much-beloved but poorly-understood species Felis catus. In this work, we conduct a survey to measure fundamental purrameters of cats and relate them to their purr-modes. Relations between these fundamental cat purrameters, which include physical (eg. size, cuddliness) and personality (eg. aggression, intelligence) traits, and purr-modes can help probe their inner lives and emotions. We find that while purr characteristics tentatively trend with several physical and personality traits, more data is required to better constrain these relationships and infer the direct predictive power of personality on purr-modes, or vice versa.

Rae Holcomb, Christopher Lam, "Catsteroseismology: Survey-based Analysis of Purr-mode Oscillations Suggests Inner Lives of Cats are Unknowable" arXiv:2503.23560 (April 1, 2025).

We report the detection of whisky in the atmosphere of the extrasolar super-Earth planet GJ 1132b from transmission spectroscopic data. It is seen both in atmospheric absorption as well as in chromospheric emission, the latter probably due to the intense heating of the co-rotating planet's day-side surface. This detection cannot be explained using natural sources of alcohol, implying that there must be a technically advanced civilisation -- possibly originating from the neighboring habitable planet GJ 1132c -- that is engaged in massive distilling operations accompanied by high levels of industrial pollution. The reason for the necessarily vast scale of production is either to produce rocket fuel for an interplanetary economy or, more likely, for an unusually high level of personal consumption. The latter hypothesis suggests a novel explanation for the Fermi Paradox (the lack of indirect or direct contact with extraterrestrials): a technically versed civilisation would be incapable of achieving the higher technical levels necessary for the development of a detectable radio signature -- much less interstellar travel -- at the suggested rates of consumption.

Frederic V. Hessman, Andrew Collier Cameron, Keith Horne, "Detection of an extraterrestrial technical civilisation on the extrasolar planet GJ 1132b" arXiv:2503.23788 (April 1, 2025).

High angular resolution holds the key to extending our knowledge in several domains of astronomical research. In addition to the development of new instruments, advancements in post-processing algorithms can enhance the performances attainable in an observation, turning archival observations into a treasure. We developed a machine-learning tool, named zoom-in, that is able to improve the angular resolution of an astronomical image by a factor of ∼100 by optimally recombining short-cadence sequences of images. After training our model on real-life photographs, we tested our method on archival images of the Moon taken through ESO instruments. We were able to achieve a remarkable spatial resolution of ∼1 m of the lunar surface. While analyzing one of the fields from the sample, we discovered structures of clear anthropic origin inside the Aristarchus crater. The features appear to be consistent with ancient ruins of cities and castles. A thorough analysis of the relevant literature allowed us to conclude that this valley corresponds to the one described in Ludovico Ariosto's "Orlando Furioso": a place where all the items lost by humans gather and pile up. Analyses of the surface brightness from our images, indicating an abnormally high albedo of ∼0.25, further corroborate this idea suggesting a conspicuous presence of glass. We infer the presence of >1 billion flasks of human wits on the lunar surface, whose origin we investigate in detail. We urge for a dedicated mission, astolfo, to be carried out by Artemis astronauts in order to recover human wits and bring them back to the Earth.

Vito Squicciarini, Irina Mirova, Francis D. Anderson, Zhiyuan He, Wahman al-Khwarizmi, "Orlando's flask: detection of a lost-and-found valley on the Moon" arXiv:2503.24242 (April 1, 2025) (Submitted for publication on 1st April 2025 to the prestigious journal Acta Prima Aprilia).

The cosmological principle posits that the universe does not exhibit any specific preference for position or direction. However, it remains unclear whether the universe has a distinct preference for parity: whether certain properties are more likely to be classified as even or odd. In this study, we analyze the largest available galaxy group catalogs to explore this hypothesis: specifically, whether the number of galaxies within a galaxy group or cluster is more likely to be odd or even. Our findings convincingly indicate that the universe indeed favors odd numbers, with results achieving a significance level well above the 4.1−σ threshold.

Shiyin Shen, Nan Li, "The Universe is Odd" arXiv:2503.22839 (April 1, 2025) (This manuscript is deliberately announced on an odd-numbered date).

For generations, people have complained that things used to be better in the past. In this paper, we investigate this change by specifically looking at creativity in astronomy. To do this, we explore if older constellations reflected a greater sense of creativity on the part of those designing them than more modern constellations do. We find that things really have become simplistic and less original over time.

Michael B. Lund, "Astronomers Getting Less Creative Over Time Is Why This Title Isn't Better" arXiv:2503.23614 (April 1, 2025) (submitted to Acta Prima Aprilia).

We all love the ecstasy that comes with submitting papers to journals or arXiv. Some have described it as yeeting their back-breaking products of labor into the void, wishing they could never deal with them ever again. The very act of yeeting papers onto arXiv contributes to the expansion of the arXiverse; however, we have yet to quantify our contribution to the cause. In this work, I investigate the expansion of the arXiverse using the arXiv astro-ph submission data from 1992 to date. I coin the term "the arXiverse constant", a0, to quantify the rate of expansion of the arXiverse. I find that astro-ph as a whole has a positive a0, but this does not always hold true for the six subcategories of astro-ph. I then investigate the temporal changes in a0 for the astro-ph subcategories and astro-ph as a whole, from which I infer the fate of the arXiverse.

Joanne Tan, "Written in the Stars: How your (pens and) papers decide the fate of the arXiverse" arXiv:2503.23957 (April 1, 2025) (Published in the 2024 issue of Acta Prima Aprila. An arXiv resubmission after a year).

I report the discovery of jacquetium (0Jq), the first naturally occurring element found since more than 80 years.

Emmanuel Jacquet, "Jacquetium, a new, naturally-occurring chemical element" arXiv:2503.24030 (April 1, 2025) (Submitted to the Journal of Improbable Science, 2025 yearly (April 1) issue).

The field of astronomy evolves rapidly, and it is essential to keep up with these changes in order to effectively communicate with the broader community. However, communication itself also changes as new words, phrases, and slang terms enter the common vernacular. This is especially true for the current youngest generations, who are capable of efficiently communicating via the Internet. In order to maintain effective communication, we explore the possibility of expanding the language used in scientific communication to include recently coined slang. This attempt at outreach, while potentially very difficult, could provide a means to expand the field and capture the attention of early-career scientists, improving retention within the field. However, our results indicate that, while possible, this method of communication is, like, probably not really worth it, no cap.

Anne E Blackwell, David L Moutard, Jake A Miller, "The Rizzeta Stone: Adopting Gen-α Colloquial Language to Improve Scientific Paper Rizz and Aura from a Skibidi Perspective" arXiv:2504.00073 (April 1, 2025).

The spherical cow approximation is widely used in the literature, but is rarely justified. Here, I propose several schemes for extending the spherical cow approximation to a full multipole expansion, in which the spherical cow is simply the first term. This allows for the computation of bovine potentials and interactions beyond spherical symmetry, and also provides a scheme for defining the geometry of the cow itself at higher multipole moments. This is especially important for the treatment of physical processes that are suppressed by spherical symmetry, such as the spindown of a rotating cow due to the emission of gravitational waves. I demonstrate the computation of multipole coefficients for a benchmark cow, and illustrate the applicability of the multipolar cow to several important problems.

Benjamin V. Lehmann, "Higher multipoles of the cow" arXiv:2504.00506 (April 1, 2025) (No cows were harmed).

We present the first--ever example of a macroscopic system in a quantum superposition. The system in question is a Siamese cat known as Lola; however, on a time scale of about 12 hours it oscillates into a different state that we refer to as "Mola". In the "Lola" state, the system is sweet and friendly and allows to cuddle itself, but in the "Mola" state, it is malevolent and witchy. When the probability of the system being in the "Mola" state is high, decoherence is strongly discouraged!

Harman Deep Kaur, Mariagrazia Trapanese, Kirill Zatrimaylov, "Macroscopic "Lola/Mola" Cat State" arXiv:2503.23433 (April 1, 2025).