Pith. sign in

REVIEW 4 major objections 5 minor 3 cited by

This paper argues that a future laser-accelerated nanocraft could reach the nearest black hole in about 60 years and test the Kerr metric, event horizons, and fundamental constants in strong gravity—provided the black hole lies within 20-25

Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗

T0 review · deepseek-v4-flash

2026-08-04 16:51 UTC pith:6NOQJHFS

load-bearing objection A clearly-hedged speculative mission concept that is honest about its own gaps, but the unique-science claim rests on an unsupported flyby measurement capability. the 4 major comments →

arxiv 2509.11222 v1 pith:6NOQJHFS submitted 2025-09-14 gr-qc astro-ph.HE

An interstellar mission to the closest black hole?

Cosimo Bambi This is my paper
classification gr-qc astro-ph.HE PACS 98.35.Jk04.70.Bw04.80.Cc
keywords Black HolesInterstellar MissionsLaser PropulsionNanocraftTests of General RelativityKerr HypothesisEvent HorizonFundamental Constants
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

This paper attempts to establish that an interstellar mission to the nearest stellar-mass black hole, though impossible today, could become realistic within the next few decades if the black hole is close enough. The author argues that a laser-accelerated gram-scale nanocraft could reach a black hole at 20 light-years in about 60 years and beam data back in another 20, completing the mission inside a century. At the target, the probe fleet could test whether the object is the Kerr black hole predicted by General Relativity, whether it has a genuine event horizon, and whether fundamental constants are unchanged in strong gravity. The reason this matters is that all three questions are currently inaccessible to Earth-based observations of black holes at astrophysical distances. The paper is explicit that feasibility hinges on the unknown distance of the nearest black hole and on future laser cost reductions.

Core claim

The paper's central claim is a feasibility argument with a clear target. Based on estimated stellar mass in the Galaxy and a population of 10^8 to 10^9 black holes, the nearest black hole is probably 18-40 light-years from the Solar System. If it is in the optimistic part of that range—within 20-25 light-years—a nanocraft accelerated by ground-based lasers to one-third the speed of light would arrive in about 60 years, and its data would reach Earth 20 years later. On location, two or more probes could reconstruct trajectories and electromagnetic signals in the strong-field region, distinguishing the Kerr spacetime from alternatives; a plunging probe would test the event horizon by comparing

What carries the argument

Key machinery is the laser-accelerated nanocraft: a gram-scale wafer carrying processor, solar panels, navigation and communication equipment, attached to a meter-scale light sail that doubles as a communication antenna. Ground-based laser arrays push the sail by radiation pressure, reaching accelerations up to about 10^5 m/s^2, so that one-third light speed is reached in roughly 17 minutes. This is the only propulsion scheme the paper treats as viable, because chemical rockets cannot provide the necessary exhaust velocity for relativistic travel. The mission then splits into a mothership retaining the light-sail antenna and one or more smaller probes that pass close to or orbit the black ho

Load-bearing premise

The load-bearing premise is that the nearest black hole actually lies within about 20-25 light-years of Earth; this distance is not controlled by any technology, and if the true distance exceeds about 40-50 light-years, a mission that returns data within a century is impossible even at near-light speed.

What would settle it

An astronomical census of isolated, accreting black holes within 150 light-years that measures the distance to the nearest one. If the closest candidate is found to be farther than about 40-50 light-years, the paper's central feasibility claim for a within-a-century mission collapses; if one is found at 18-25 light-years, the premise is confirmed and mission planning becomes concrete.

Watch this falsifier. Get emailed when new claim-graph text bears on it.

If this is right

  • A within-a-century mission requires the nearest black hole to be within about 20-25 light-years and a probe speed of at least one-third the speed of light.
  • The mission can perform direct strong-field tests of the Kerr hypothesis by reconstructing probe trajectories and signal propagation around the black hole.
  • A plunging probe yields a clean observational signature: General Relativity predicts a gradually redshifted signal that fades forever, while horizonless alternatives such as fuzzballs predict a sudden interruption when the probe hits the surface.
  • Fine-structure doublet ratios measured near the black hole can constrain variation of the fine structure constant without contamination from photon redshift.
  • If the nearest black hole is beyond 40-50 light-years, the paper concludes the mission lasts over a century no matter how advanced the technology.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Editorial extension: the practical near-term payoff is not the mission itself but a targeted observational campaign to find isolated accreting black holes within roughly 150 light-years, since the measured distance is the single factor that decides whether the scenario is worth planning.
  • Editorial extension: the cost assumption is testable on a decadal timescale; if the price per coherent watt does not continue its historical decline, the billion-euro laser array the mission needs will not materialize even if a nearby black hole is found.
  • Editorial extension: the same fleet architecture—mothership plus small probes exchanging signals—could serve as a general-purpose relativistic laboratory, with the black hole replaced by other compact objects or a close-pass target elsewhere in the Galaxy.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit.

Referee Report

4 major / 5 minor

Summary. The paper proposes a speculative interstellar mission to the nearest stellar-mass black hole, estimated to lie 18–40 light-years away. It argues that a laser-accelerated gram-scale nanocraft, traveling at ~1/3 the speed of light, could reach such a black hole in ~60 years and perform tests of the Kerr hypothesis, the existence of an event horizon, and possible variations of fundamental constants. The manuscript explicitly acknowledges that the idea is impossible today and speculative, but suggests that the technology may be available in 20–30 years, with the whole mission lasting under a century if the target is within ~20–25 light-years. The core scientific claim is conditional on the actual distance of the closest black hole and on future technology, as the author states.

Significance. If the proposed mission were realizable, it would offer a unique, local test of strong-field gravity and event-horizon physics, complementing astrophysical observations. The paper's strengths are its honest framing, its use of published astrophysical inputs for the distance estimate (though the estimate is a rough average), and its correct basic physics: the rocket-equation argument in Section 3 and the fine-structure doublet scaling in Section 4.4.3 are sound as far as they go. However, the central feasibility claim is not supported by any engineering or sensitivity analysis. In particular, the science phase is left at a qualitative level, and the paper itself admits a critical orbital-capture gap. The uniqueness of the proposed tests relative to existing or near-future observations is asserted rather than demonstrated. These are load-bearing gaps for the manuscript's central claim that such a mission could address fundamental questions of modern physics.

major comments (4)
  1. [Section 4.3, Figure 2] The paper states that in the orbiting configuration 'it is not clear if and how the mothership and the probes can move from the unbound orbits of phase 2 to bound orbits around the black hole.' This is a load-bearing gap: the orbiting configuration is the only one in which the claimed precision ('the precision of the measurements increases with the number of the orbits') can be realized. No deceleration mechanism is described anywhere in the manuscript. Without a concrete orbital-capture scenario, the unique-science claim rests on an unstated assumption.
  2. [Sections 4.3–4.4] In the flyby configuration, which the paper offers as the alternative, the probes pass through the strong-gravity region in a very short time. For a 10 solar-mass black hole, GM/c^2 ≈ 15 km; at 0.33c, the time spent inside r < 100 GM/c^2 is only ~30 ms. The manuscript provides no quantitative argument that a gram-scale probe can measure the Kerr metric, an event-horizon cutoff, or the fine-structure ratio to the claimed 'precise and accurate' level in this window, nor any link budget for transmitting these measurements to the mothership during the encounter. The statement that 'a large number of small probes may help' is not a substitute for a signal-to-noise and data-rate analysis.
  3. [Section 1, 4.4] The paper states that a similar mission 'can make sense only if it can do something that cannot be done with astrophysical observations from the Earth or with observatories orbiting the Earth.' Yet Section 4.4 describes the proposed tests only qualitatively and does not compare them with existing or planned observational capabilities (e.g., Event Horizon Telescope shadow measurements, gravitational-wave ringdown tests, or X-ray reflection spectroscopy). The claimed uniqueness of the mission is therefore not established.
  4. [Section 4.1] The feasibility timeframe rests on the assumption that the cost per coherent watt will continue to decline at the same rate as in the past 20 years, reducing the laser-array cost from about one trillion EUR to one billion EUR in 20–30 years. This is an extrapolation with no cited evidence or scenario analysis. A factor-1000 cost reduction is a strong claim that is load-bearing for the central 'may be possible in 20–30 years' thesis. The manuscript should at least provide a reference for the historical trend and discuss the physical/technological limits of such a decline.
minor comments (5)
  1. [Section 1] Typo: 'so send' should be 'to send'.
  2. [Section 3] Typo: 'mora advanced' should be 'more advanced'.
  3. [Section 4.4.2] Grammar: 'Do astrophysical black hole have an event horizon?' should be 'Do astrophysical black holes have event horizons?'.
  4. [Section 2] The distance estimate is an order-of-magnitude average and should be presented with the caveat that the local black-hole distribution may be non-uniform (e.g., due to natal kicks). The current text already acknowledges the uncertainty, but a short remark would help.
  5. [Figure 2] The labels 'Probe-2' and the flyby trajectories are not defined in the caption; a more explicit description of the geometry would improve clarity.

Circularity Check

0 steps flagged

No significant circularity: the proposal's estimates and science discussion use independent astrophysical inputs and standard GR results, not the mission's own outputs.

full rationale

The paper is a speculative mission study rather than a derivation of predictions from fitted parameters. The distance estimate (Section 2) combines an independent stellar-mass measurement [13], independent black-hole population estimates [2,3], and a local stellar density [14]; none of these are outputs of the proposed mission. The acceleration/cost discussion (Section 4.1) extrapolates an external cost trend and does not reuse any mission-derived quantity as a prediction. The science-phase scenarios (Section 4.4) invoke standard General Relativity (e.g., the Kerr metric, event-horizon redshift, and the fine-structure doublet formula Δν/ν ∼ α²Z⁴) and cite reviews [5-9] that exist independently; the author's self-citations are acknowledged context, not load-bearing uniqueness theorems. The paper openly flags the major feasibility gap—'it is not clear if and how the mothership and the probes can move from the unbound orbits of phase 2 to bound orbits around the black hole'—which is a correctness/engineering risk, not circular reasoning. No fitted input is relabeled as a prediction, and no central claim reduces by construction to its inputs.

Axiom & Free-Parameter Ledger

0 free parameters · 6 axioms · 0 invented entities

The central feasibility claim depends on: (1) the unknown distance to the nearest black hole, estimated from astrophysical models with order-of-magnitude uncertainty; (2) the assumption that laser propulsion cost and performance will improve as extrapolated; and (3) standard GR predictions (Kerr metric, event horizon, local Lorentz invariance) used in the proposed experiments. No free parameters are fitted; the inputs are published estimates. No new entities are introduced.

axioms (6)
  • domain assumption Stellar-mass black holes form from collapse of stars with mass above about 20 solar masses and populate the Galaxy with 10^8 to 10^9 members
    Used in Section 2 to estimate the distance to the closest black hole; based on cited astrophysical models [1-3].
  • domain assumption Isolated black holes can be detected via accretion from the interstellar medium
    Assumed in Section 2 to identify a target; cited to Refs [15-22].
  • domain assumption Nanocraft can be accelerated by ground-based lasers to relativistic speeds
    Basis for the mission architecture in Section 3, citing laser propulsion literature [10,11,23,24].
  • standard math The fine-structure doublet splitting delta-nu/nu ~ alpha^2 Z^4 is independent of redshift, so a measured variation indicates a change in alpha
    Used in Section 4.4.3 to propose a test of fundamental constant variation; standard atomic physics.
  • domain assumption Kerr hypothesis: astrophysical black holes are described by the Kerr metric if GR holds
    Section 4.4.1 defines the test target; standard GR.
  • ad hoc to paper Laser cost per coherent watt will continue to decline at the past 20-year rate
    Section 4.1 uses this to argue the mission cost falls to about 1 billion EUR in 20-30 years; this trend extrapolation is not established.

pith-pipeline@v1.3.0-alltime-deepseek · 7883 in / 10540 out tokens · 111801 ms · 2026-08-04T16:51:34.599970+00:00 · methodology

0 comments
read the original abstract

In this manuscript, I discuss the possibility of sending a small probe to the closest black hole with the goal of addressing some fundamental questions of modern physics. Are astrophysical black holes the Kerr black holes predicted by General Relativity? Do astrophysical black holes have an event horizon? Is the physics around a black hole the same physics as in our laboratories on Earth? While we do not have the technology for a similar mission today, it may be available in the next 20-30 years. The whole mission may last up to a century (depending on the actual distance of the black hole and the speed of the probe), but it may represent a unique opportunity to perform precise and accurate tests of General Relativity in the strong field regime.

Figures

Figures reproduced from arXiv: 2509.11222 by Cosimo Bambi.

Figure 1
Figure 1. Figure 1: Sketch of a nanocraft. The wafer is the main body of the satellite, with a computer processor, solar panels, [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: Orbiting configuration (left picture): the mothership with the light sail acting as an antenna to send the collected data to Earth orbits the black hole at a relatively large distance; the small probes orbit closer to the black hole and communicate with the mothership. Flyby configuration (right picture): the spaceship fleet (mothership + small probes) passes through the gravitational field of the black ho… view at source ↗

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Forward citations

Cited by 3 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. A Space Mission to Earth's Nearest Black Hole: Reality or Science Fiction?

    gr-qc 2026-07 conditional novelty 4.0

    An interstellar nanocraft mission to a nearby black hole is technologically speculative but potentially feasible within decades and could deliver precision strong-field tests of General Relativity.

  2. Testing Black Holes with Interstellar Missions: II. Flyby Probes

    gr-qc 2026-07 unverdicted novelty 4.0

    Flyby probes without spacecraft deceleration may still enable black-hole and GR tests beyond what Solar System observatories can achieve for the foreseeable future.

  3. Testing Black Holes with Interstellar Missions: I. Orbiting Probes

    gr-qc 2026-05 unverdicted novelty 4.0

    Preliminary analysis of orbiting spacecraft around a black hole to test the compact object's nature and General Relativity under the assumption of deceleration capability.

Reference graph

Works this paper leans on

42 extracted references · 1 canonical work pages · cited by 3 Pith papers

  1. [1]

    INTRODUCTION Stellar-mass black holes are the final products of the evolution of heavy stars, those with masses ex­ ceeding∼20𝑀 ⊙ [1]. Current astrophysical models predict that in our Galaxy there are10 8-109 black holes formed from the collapse of heavy stars [2, 3] and simple estimates suggest that the closest black hole may be at 20-40 light years from...

  2. [2]

    Are astrophysical black holes the Kerr black holes predicted by Einstein’s theory of General Relativity?

  3. [3]

    Do astrophysical black holes have an event hori­ zon causally separating the black hole from the exterior region?

  4. [4]

    Isthephysicsinthestronggravitationalfieldofa blackholethesamephysicsasinourlaboratories on Earth? This idea was first discussed in Ref. [4]. As I will show in the next sections, it is certainly very spec­ ulative and technologically challenging, but it is not completely unrealistic. Certainly it is impossible to­ day, but it may be possible in the future....

  5. [5]

    The total mass in the form of stars in our Galaxy is estimated to be𝑀 stars = (6.1±1.1)·10 10 𝑀⊙ [13]

    THE CLOSEST BLACK HOLE Let us estimate the distance of the closest black hole from the Solar System. The total mass in the form of stars in our Galaxy is estimated to be𝑀 stars = (6.1±1.1)·10 10 𝑀⊙ [13]. Most black holes in our Galaxy are isolated black holes, without any compan­ ion object [2]. The estimate of the total number of isolated black holes in ...

    Pith/arXiv arXiv 2025

  6. [6]

    It is clear that the probe must travel at a velocity of some fractions of the speed of light to reach the black hole within a reasonable time

    THE SPACECRAFT Let us assume we discover a black hole at 20 light-years from Earth and we want to send a probe to study the object. It is clear that the probe must travel at a velocity of some fractions of the speed of light to reach the black hole within a reasonable time. This already rules out chemical propulsion of cur­ rent rockets. The Tsiolkovsky r...

  7. [7]

    fundamental

    THE MISSION The whole mission can be roughly divided into four phases: 1) acceleration of the probe, 2) interstellar trip, 3) approaching to the black hole and preparation for the scientific experiments, and 4) scientific experi­ ments. If the black hole is at 20 light-years from Earth and we accelerate the nanocraft to reach 1/3 of the speed of light, th...

    2023

  8. [8]

    The idea was first proposed in Ref

    CONCLUSIONS In this manuscript, I outlined the idea of sending a small probe to the closest black hole with the goal of testing the actual nature of the object and address some fundamental questions of modern physics. The idea was first proposed in Ref. [4]. While the idea is very speculative and technologically challenging, and certainly it is impossible...

  9. [9]

    The nanocraft may travel at 1/3 of the speed of light and the duration of the whole mission can be within a century

    If the black hole is within 20-25 light-years of Earth, the technology necessary for the mission may be developed in the next 20-30 years. The nanocraft may travel at 1/3 of the speed of light and the duration of the whole mission can be within a century

  10. [10]

    If the black hole is not within 20-25 light-years of Earth, but still within 40-50 light-years, the technological requirements are more challenging. The probe should travel at a speed closer to the speed of light in order to remain with a mission with a duration within a century, and we may need more than 20-30 years to develop the tech­ nology necessary ...

  11. [11]

    Even in the most optimistic situation (case 1: the black hole is within 20-25 light-years), there are cer­ tainly many technological problems to solve

    If the distance of the black hole is more than 40-50 light-years, it is not a problem of technol­ ogy: the black hole is simply too far from us and, even if the nanocraft could travel close to the speed of light, the whole mission would last over a century. Even in the most optimistic situation (case 1: the black hole is within 20-25 light-years), there a...

  12. [12]

    Bambi, Symmetry17, 1393 (2025); https://doi.org/10.3390/sym17091393 [arXiv:2507.15270 [astro-ph.HE]]

    C. Bambi, Symmetry17, 1393 (2025); https://doi.org/10.3390/sym17091393 [arXiv:2507.15270 [astro-ph.HE]]

    Pith/arXiv arXiv 2025

  13. [13]

    Olejak, K

    A. Olejak, K. Belczynski, T. Bulik and M. Sobolewska, Astron. Astrophys.638, A94 (2020); https://doi.org/10.1051/0004-6361/201936557 [arXiv:1908.08775 [astro-ph.SR]]

    Pith/arXiv arXiv 2020

  14. [14]

    F. X. Timmes, S. E. Woosley and T. A. Weaver, Astrophys. J.457, 834 (1996); https://doi.org/10.1086/176778 x–5 Conference section [arXiv:astro-ph/9510136 [astro-ph]]

    Pith/arXiv arXiv 1996

  15. [15]

    Bambi, iScience28, 113142 (2025); https://doi.org/10.1016/j.isci.2025.113142 [arXiv:2504.14576 [gr-qc]]

    C. Bambi, iScience28, 113142 (2025); https://doi.org/10.1016/j.isci.2025.113142 [arXiv:2504.14576 [gr-qc]]

    arXiv 2025

  16. [16]

    Bambi, Rev

    C. Bambi, Rev. Mod. Phys.89, 025001 (2017); https://doi.org/10.1103/RevModPhys.89.025001 [arXiv:1509.03884 [gr-qc]]

    Pith/arXiv arXiv 2017

  17. [17]

    C. Bambi,Black Holes: A Laboratory for Testing Strong Gravity(Springer Sin­ gapore, 2017); ISBN 978-981-10-4523-3, 978-981-13-5158-7, 978-981-10-4524-0; https://doi.org/10.1007/978-981-10-4524-0

    doi:10.1007/978-981-10-4524-0 2017

  18. [18]

    Bambi and A.Cardenas-Avendano,Recent Progress on Gravity Tests

    C. Bambi and A.Cardenas-Avendano,Recent Progress on Gravity Tests. Challenges and Future Perspectives (Springer Singapore, 2024); ISBN 978-981–972870-1, 978-981–972873-2, 978-981–972871-8; https://doi.org/10.1007/978-981-97-2871-8

    doi:10.1007/978-981-97-2871-8 2024

  19. [19]

    Tripathi, Y

    A. Tripathi, Y. Zhang, A. B. Abdikamalov, D. Ayzenberg, C. Bambi, J. Jiang, H. Liu and M. Zhou, Astrophys. J.913, 79 (2021); https://doi.org/10.3847/1538-4357/abf6cd [arXiv:2012.10669 [astro-ph.HE]]

    Pith/arXiv arXiv 2021

  20. [20]

    Bambi, Arab

    C. Bambi, Arab. J. Math.11, no.1, 81-90 (2022); https://doi.org/10.1007/s40065-021-00336-y [arXiv:2106.04084 [gr-qc]]

    Pith/arXiv arXiv 2022

  21. [21]

    Marx, Nature211, 22-23 (1966); https://doi.org/10.1038/211022a0

    G. Marx, Nature211, 22-23 (1966); https://doi.org/10.1038/211022a0

    doi:10.1038/211022a0 1966

  22. [22]

    J. L. Redding, Nature213, 588-589 (1967); https://doi.org/10.1038/213588a0

    doi:10.1038/213588a0 1967

  23. [23]

    Lubin, J

    P. Lubin, J. Br. Interplanet. Soc. (JBIS)69, 40-72 (2016)

    2016

  24. [24]

    T. C. Licquia and J. A. New­ man, Astrophys. J.806, 96 (2015); https://doi.org/10.1088/0004-637X/806/1/96 [arXiv:1407.1078 [astro-ph.GA]]

    Pith/arXiv arXiv 2015

  25. [25]

    Lutsenko, G

    A. Lutsenko, G. Carraro, V. Korchagin, R. Tkachenko and K. Vieira, Astrophys. J.990, 88 (2025); https://doi.org/10.3847/1538-4357/adec66 [arXiv:2507.06052 [astro-ph.GA]]

    Pith/arXiv arXiv 2025

  26. [26]

    V. F. Shvartsman, Soviet Astron. AJ15, 377 (1971)

    1971

  27. [27]

    Meszaros, Astron

    P. Meszaros, Astron. Astrophys.44, 59-68 (1975)

    1975

  28. [28]

    McDowell, Mon

    J. McDowell, Mon. Not. Roy. Astron. Soc.217, 77-85 (1985); https://doi.org/10.1093/mnras/217.1.77

    doi:10.1093/mnras/217.1.77 1985

  29. [29]

    Campanaand M.C

    S. Campanaand M.C. Pardi, Astron. Astrophys.277, 477 (1993)

    1993

  30. [30]

    Fujita, S

    Y. Fujita, S. Inoue, T. Nakamura, T. Man­ moto and K. E. Nakamura, Astrophys. J. Lett. 495, L85 (1998); https://doi.org/10.1086/311220 [arXiv:astro-ph/9712284 [astro-ph]]

    Pith/arXiv arXiv 1998

  31. [31]

    Tsuna, N

    D. Tsuna, N. Kawanaka and T. Totani,X-ray De­ tectability of Accreting Isolated Black Holes in Our Galaxy, Mon. Not. Roy. Astron. Soc.477, 791-801 (2018); https://doi.org/10.1093/mnras/sty699 [arXiv:1801.04667 [astro-ph.HE]]

    Pith/arXiv arXiv 2018

  32. [32]

    S. S. Kimura, K. Kashiyama and K. Ho­ tokezaka,Multiwavelength Emission from Magnetically Arrested Disks around Isolated Black Holes, Astrophys. J. Lett.922, L15 (2021); https://doi.org/10.3847/2041-8213/ac35dc [arXiv:2109.14389 [astro-ph.HE]]

    Pith/arXiv arXiv 2021

  33. [33]

    Murchikova and K

    L. Murchikova and K. Sahu,Observability of Isolated Stellar-mass Black Holes, Astrophys.J.Lett.988, L12 (2025); https://doi.org/10.3847/2041-8213/ade7f8 [arXiv:2506.20711 [astro-ph.GA]]

    Pith/arXiv arXiv 2025

  34. [34]

    Lubin,The Path to Transformational Space Exploration(World Scientific Publishing Company, 2022); ISBN 978-981-12-4903-7, 978-981-12-4828-3; https://doi.org/10.1142/11918

    P. Lubin,The Path to Transformational Space Exploration(World Scientific Publishing Company, 2022); ISBN 978-981-12-4903-7, 978-981-12-4828-3; https://doi.org/10.1142/11918

    doi:10.1142/11918 2022

  35. [35]

    J. Y. Lin, C. M. de Sterke, O. Ilic and B. T. Kuhlmey, https://doi.org/10.48550/arXiv.2502.17828 [arXiv:2502.17828 [astro-ph.IM]]

    Pith/arXiv arXiv doi:10.48550/arxiv.2502.17828

  36. [36]

    C. P. Bandutunga, P. G. Sibley, M. J. Ireland and R. L. Ward, J. Opt. Soc. Am. B38, 1477 (2021); https://doi.org/10.1364/JOSAB.414593

    work page doi:10.1364/josab.414593 2021

  37. [37]

    S. D. Mathur and M. Mehta,The Fuzzball ParadigminThe Black Hole Information Para­ dox: A Fifty-Year Journey(Eds. A. Akil and C. Bambi, Springer Singapore, 2025), pp 295-340; https://doi.org/10.1007/978-981-96-6170-1_11 [arXiv:2412.09495 [hep-th]]

    Pith/arXiv arXiv 2025

  38. [38]

    C. M. Will, Living Rev. Rel.17, 4 (2014); https://doi.org/10.12942/lrr-2014-4 [arXiv:1403.7377 [gr-qc]]

    Pith/arXiv arXiv 2014

  39. [39]

    J. P. Uzan, Rev. Mod. Phys.75, 403 (2003); https://doi.org/10.1103/RevModPhys.75.403 [arXiv:hep-ph/0205340 [hep-ph]]

    Pith/arXiv arXiv 2003

  40. [40]

    J. P. Uzan, Living Rev. Rel.14, 2 (2011); https://doi.org/10.12942/lrr-2011-2 [arXiv:1009.5514 [astro-ph.CO]]

    Pith/arXiv arXiv 2011

  41. [41]

    Bambi,Search for Variations of Fundamental Con­ stantsinRecent Progress on Gravity Tests

    C. Bambi,Search for Variations of Fundamental Con­ stantsinRecent Progress on Gravity Tests. Challenges and Future Perspectives(Eds. C. Bambi and A. Carde­ nas-Avendano, Springer Singapore, 2024), pp 417-431; https://doi.org/10.1007/978-981-97-2871-8_10 [arXiv:2210.11959 [gr-qc]]

    Pith/arXiv arXiv 2024

  42. [42]

    J. C. Berengut, V. V. Flambaum, A. Ong, J. K. Webb, J. D. Barrow, M. A. Barstow, S. P. Preval and J. B. Holberg, Phys. Rev. Lett.111, 010801 (2013); https://doi.org/10.1103/PhysRevLett.111.010801 [arXiv:1305.1337 [astro-ph.CO]]. x–6

    Pith/arXiv arXiv 2013