تکینگی های آتی کیهانی در کیهانشناسی راستال

نوع مقاله : مقاله پژوهشی کامل

نویسنده

گروه پژوهشی نجوم و اخترفیزیک نظری و تجربی، مرکز تحقیقات نجوم و اخترفیزیک، دانشگاه مراغه، مراغه، ایران

10.22055/jrmbs.2020.15927

چکیده

در این مقاله، پس از معرفی انواع تکینگی‌هایی که برای آینده کیهان پیش بینی می‌شوند، درآمدی مختصر بر نظریه راستال ارائه می‌شود. در ادامه، با استفاده از معادلات فریدمان متناظر با جهانی تخت در نظریه راستال، امکان حصول تکینگی-های آتی مختلف را در دو حالت بررسی می‌کنیم. ابتدا زمانیکه کیهان با سیالی همگن و همسانگرد که نسبت فشار به چگالی انرژی آن ثابت است و سپس در حالتی که این نسبت همواره ثابت نیست و کیهان با آهنگ خاصی تحول می‌یابد. در حالیکه در حالت اول تکینگی‌ایی برای آینده کیهان پیش بینی نمی‌شود، در حالت دوم برخی از انواع تکینگی امکان وقوع خواهند داشت.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Cosmic future singularities in Rastall cosmology

نویسنده [English]

  • Hooman Moradpour
Astrophysics and Cosmology group, Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), P.O. Box 55134-441, Maragha, Iran
چکیده [English]

In this paper, after addressing various future singularities, predicted for Cosmos, an introductory note on Rastall theory is provided. Thereinafter, considering a flat Universe, the Friedmann equations of Rastall theory are derived, and the possibility of obtaining various singularities are studied in two cases. In the first case, the cosmic fluid is an isotropic and homogenous fluid while the ratio of its pressure and density is constant. In the second case, the mentioned ratio is not always constant and Universe evolves with a specified rate. The study claims that whereas it is not predicted any future singularity for the first model of cosmos, some types of future singularities may be inevitable in the second one.

کلیدواژه‌ها [English]

  • cosmology
  • Singularity
  • Rastall theory
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