arXiv - PHYS - Popular Physics最新文献

Did WISE detect Dyson Spheres/Structures around Gaia-2MASS-selected stars? WISE探测到盖亚-2MASS选择的恒星周围的戴森球/结构了吗？

arXiv - PHYS - Popular Physics Pub Date : 2024-09-17 DOI: arxiv-2409.11447

Andrew W. Blain

{"title":"Did WISE detect Dyson Spheres/Structures around Gaia-2MASS-selected stars?","authors":"Andrew W. Blain","doi":"arxiv-2409.11447","DOIUrl":"https://doi.org/arxiv-2409.11447","url":null,"abstract":"Soon after the release of the WISE all-sky catalogue of 500 million\u0000mid-infrared (IR) objects, suggestions were made that it could be used to\u0000search for extrasolar devices constructed by an advanced civilization to\u0000convert a significant fraction of their host star's luminosity into useful\u0000work: \"technostructures\", \"megastructures\" or \"Dyson spheres/structures\",\u0000hereafter DSMs, whose inevitable waste heat would be seen by WISE at mid-IR\u0000wavelengths. However, a trawl of several million potentially-habitable\u0000Gaia-detected stars for mid-IR-excess signatures is fraught with danger, due to\u0000both noise from such a large sample and, more importantly, confusion with the\u0000emission from dusty background galaxies. In light of a recent claim of seven\u0000potential DSMs in MNRAS, a brief rebuttal appeared on arXiv. Further to this\u0000response, the relevance of WISE-detected galaxies is discussed in more detail,\u0000leading to a seemingly tight limit on the number and lifetime of DSMs, and\u0000indeed intelligent worlds, in the ~600-pc-radius region patrolled by Gaia.\u0000However, the detectability of DSMs is questioned: a DSM might extinguish its\u0000star at optical/near-IR wavelengths, and thus either not appear or appear\u0000anomalously faint in a stellar catalogue. Moreover, a civilization advanced\u0000enough to construct a DSM is likely to be advanced enough to use\u0000countermeasures to mask its presence from us.","PeriodicalId":501348,"journal":{"name":"arXiv - PHYS - Popular Physics","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Ancient Egyptian Cosmological Vignette: First Visual Evidence of the Milky Way and Trends in Coffin Depictions of the Sky Goddess Nut 古埃及宇宙学小故事：银河系的首个视觉证据和棺木中对天空女神坚果的描绘趋势

arXiv - PHYS - Popular Physics Pub Date : 2024-09-16 DOI: arxiv-2409.10265

Or Graur

{"title":"The Ancient Egyptian Cosmological Vignette: First Visual Evidence of the Milky Way and Trends in Coffin Depictions of the Sky Goddess Nut","authors":"Or Graur","doi":"arxiv-2409.10265","DOIUrl":"https://doi.org/arxiv-2409.10265","url":null,"abstract":"Several studies have argued that the Milky Way was a representation of the\u0000ancient Egyptian sky goddess Nut. Here, I test this assumption by examining\u0000Nut's visual depictions on ancient Egyptian coffins. I assemble a catalog of\u0000555 coffin elements, which includes 118 cosmological vignettes from the\u000021st/22nd Dynasties, and report several observations. First, I find that the\u0000cosmological vignette on the outer coffin of Nesitaudjatakhet bears a unique\u0000feature: a thick, undulating black curve that bisects Nut's star-studded body\u0000and recalls the Great Rift that cleaves the Milky Way in two. Moreover, it\u0000resembles similar features identified as the Milky Way on the bodies of Navajo,\u0000Hopi, and Zuni spiritual beings. Hence, I argue that the undulating curve on\u0000Nut's body is the first visual representation of the Milky Way identified in\u0000the Egyptian archaeological record. However, its rarity strengthens the\u0000conclusion reached by Graur (2024a): Though Nut and the Milky Way are linked,\u0000they are not synonymous. Instead of acting as a representation of Nut, the\u0000Milky Way is one more celestial phenomenon that, like the Sun and the stars, is\u0000associated with Nut in her role as the sky. Second, Nut's body is decorated\u0000with stars in only a quarter of the vignettes. If we associate Nut's naked and\u0000star-studded forms with the day and night sky, respectively, we would expect to\u0000see stars in half of the vignettes. This null hypothesis is rejected at\u0000$>6sigma$ statistical significance. For whatever reason, it appears that the\u0000Egyptians of the 21st/22nd Dynasties preferred the day sky over the night sky.\u0000Finally, I discuss the interplay between Nut's cosmological vignette and\u0000full-length portraits inside coffins from the New Kingdom to the Roman Period\u0000in light of Nut's combined cosmological and eschatological roles as an\u0000embodiment of the coffin.","PeriodicalId":501348,"journal":{"name":"arXiv - PHYS - Popular Physics","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The hardest-hit home run? 最难击出的本垒打？

arXiv - PHYS - Popular Physics Pub Date : 2024-08-26 DOI: arxiv-2408.14529

Donald C. Warren

引用次数: 0

Projections of Earth's technosphere. I. Scenario modeling, worldbuilding, and overview of remotely detectable technosignatures 地球技术层的预测。I. 情景建模、世界构建和遥感技术特征概述

arXiv - PHYS - Popular Physics Pub Date : 2024-08-23 DOI: arxiv-2409.00067

Jacob Haqq-Misra, George Profitiliotis, Ravi Kopparapu

{"title":"Projections of Earth's technosphere. I. Scenario modeling, worldbuilding, and overview of remotely detectable technosignatures","authors":"Jacob Haqq-Misra, George Profitiliotis, Ravi Kopparapu","doi":"arxiv-2409.00067","DOIUrl":"https://doi.org/arxiv-2409.00067","url":null,"abstract":"This study uses methods from futures studies to develop a set of ten\u0000self-consistent scenarios for Earth's 1000-year future, which can serve as\u0000examples for defining technosignature search strategies. We apply a novel\u0000worldbuilding pipeline that evaluates the dimensions of human needs in each\u0000scenario as a basis for defining the observable properties of the technosphere.\u0000Our scenarios include three with zero-growth stability, two that have collapsed\u0000into a stable state, one that oscillates between growth and collapse, and four\u0000that continue to grow. Only one scenario includes rapid growth that could lead\u0000to interstellar expansion. We examine absorption spectral features for a few\u0000scenarios to illustrate that nitrogen dioxide can serve as a technosignature to\u0000distinguish between present-day Earth, pre-agricultural Earth, and an\u0000industrial 1000-year future Earth. Three of our scenarios are spectrally\u0000indistinguishable from pre-agricultural Earth, even though these scenarios\u0000include expansive technospheres. Up to nine of these scenarios could represent\u0000steady-state examples that could persist for much longer timescales, and it\u0000remains possible that short-duration technospheres could be the most abundant.\u0000Our scenario set provides the basis for further systematic thinking about\u0000technosignature detection as well as for imagining a broad range of\u0000possibilities for Earth's future.","PeriodicalId":501348,"journal":{"name":"arXiv - PHYS - Popular Physics","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142184395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Quantum Technologies and AI -- Interview with Tommaso Calarco 量子技术与人工智能 -- 专访托马索-卡拉科（Tommaso Calarco

arXiv - PHYS - Popular Physics Pub Date : 2024-08-20 DOI: arxiv-2408.16014

Matthias Klusch, Jörg Lässig, Frank K. Wilhelm

引用次数: 0

On the practicalities of producing a nuclear weapon using high-assay low-enriched uranium 关于使用高分辨低浓缩铀生产核武器的实用性

arXiv - PHYS - Popular Physics Pub Date : 2024-08-16 DOI: arxiv-2408.16013

P. Cosgrove, N. Read

引用次数: 0

Integrating Evolutionary Biology into Physics Classroom: Scaling, Dimension, Form and Function 将生物进化融入物理课堂：比例、尺寸、形式和功能

arXiv - PHYS - Popular Physics Pub Date : 2024-08-07 DOI: arxiv-2408.04070

Kausik S Das, Larry Gonick, Salem Al Mosleh