A Peek Outside Our Universe

Enrique Gaztanaga,Pablo Fosalba

doi:10.3390/sym14020285

Enrique Gaztanaga, Pablo Fosalba

Open Access

https://doi.org/10.3390/sym14020285

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Abstract

According to general relativity (GR), a universe with a cosmological constant Λ, like ours, is trapped inside an event horizon, r<3/Λ. What is outside? We show, using Israel (1967) junction conditions, that there could be a different universe outside. Our universe looks like a black hole for an outside observer. Outgoing radial null geodesics cannot escape our universe, but incoming photons can enter and leave an imprint on our CMB sky. We present a picture of such a fossil record from the analysis of CMB maps that agrees with the black hole universe predictions but challenges our understanding of the origin of the primordial universe.

Highlights

An event horizon (EH) r∗, or trapped surface, for a given observer can be defined as the distance beyond which this observer will never see: r < r∗
The Schwarzschild (SW) metric is commonly used to describe the outside of black hole (BH) or stars and it should be understood as a perturbation inside a larger background
It takes t = ∞ in SW time to asymptotically reach R∗. This proves that the joint BHU metric is a solution to Einstein’s field equations with no surface terms in the junction. This is equivalent to stating that the Λ term corresponds to a trapped surface R∗ = 1/HΛ in the FLRW metric which matches the EH of a BH

Summary

Introduction

Dimensional analysis tells us that a relativistic (c) gravitational (G) system of mass M has an associated EH: r∗ ' GM/c2. We will show first how these EHs appear as solutions to Einstein’s field equations and how the different. Einstein’s field equations for that metric in empty space ρ = p = Λ = 0 result in the Schwarzschild (SW) metric: Published: 31 January 2022. Where M can be interpreted as a singular point mass at r = 0. As it is well known, the EH at r∗ = 2GM prevents us from seeing such a naked singularity [2]. We include a constant ρvac = V = V (φ) = − pvac to account for vacuum energy (or the potential of a trapped scalar field), which is physically degenerate with Λ.

The FLRW Metric and Λ

SW–FLRW Perturbation

Outside Our FLRW Universe

Causal Structure

A Peek Outside