[Paper Review] A Heliosheath Model for the Origin of the CMB Quadrupole Moment

H. N. Sharpe|ArXiv.org|May 18, 2009

Cosmology and Gravitation Theories12 references4 citations

TL;DR

This paper proposes a non-cosmological origin for the cosmic microwave background (CMB) quadrupole moment, suggesting that geometric distortions from the solar wind's termination shock and heliosheath structure could imprint anisotropies on CMB radiation during its propagation. Temporal variations in solar wind pressure may modulate these distortions, potentially affecting the CMB's multipole moments and small-scale angular power spectrum.

ABSTRACT

A non-cosmological origin for the CMB quadrupole moment is suggested in this paper. Geometric distortions to an otherwise isotropic CMB could be imprinted on the CMB radiation as it propagates through the asymmetric termination shock formed at the boundary of the solar wind and the local interstellar medium. In addition to this boundary distortion, the Voyager spacecraft observed abrupt changes in plasma properties and rapidly fluctuating magnetic and electric fields as they recently crossed the termination shock and entered the heliosheath. Several mechanisms are discussed which could potentially imprint the termination shock distortion on the CMB. Temporal variations of this distortion due to solar wind pressure wind changes could manifest in the multipole moments of the CMB. Speculations are presented for the effect of heliosheath radiative and dynamical processes on the observed small-scale angular power spectrum of the CMB.

Motivation & Objective

• To challenge the standard cosmological interpretation of the CMB quadrupole moment by proposing a local astrophysical origin.
• To investigate whether asymmetric structures in the heliosheath—formed by the solar wind interacting with the local interstellar medium—can distort CMB radiation.
• To explore how temporal fluctuations in solar wind pressure might modulate these distortions and affect CMB multipole moments.
• To examine the potential influence of heliosheath radiative and dynamical processes on the observed small-scale CMB angular power spectrum.
• To stimulate discussion on alternative explanations for the CMB quadrupole that do not rely on primordial cosmological physics.

Proposed method

• Modeling the termination shock as a geometric boundary with asymmetric properties due to solar wind dynamics.
• Analyzing how CMB radiation propagating through this distorted boundary could acquire anisotropic features.
• Considering the role of abrupt plasma and field changes observed by Voyager spacecraft at the heliosheath interface.
• Examining temporal variations in the shock structure due to solar wind pressure fluctuations as a driver of time-varying CMB distortions.
• Speculating on the imprint of these distortions on the CMB multipole moments, particularly the quadrupole.
• Assessing the potential impact of heliosheath processes on the small-scale angular power spectrum of the CMB.

Experimental results

Research questions

• RQ1 Can the CMB quadrupole moment originate from local astrophysical structures rather than primordial cosmological inhomogeneities?
• RQ2 To what extent can the termination shock and heliosheath distort CMB radiation via geometric and plasma-induced effects?
• RQ3 How do time-varying solar wind conditions modulate the distortion of CMB radiation in the heliosheath?
• RQ4 What observable signatures might heliosheath dynamics leave on the CMB multipole moments and angular power spectrum?
• RQ5 Could non-cosmological processes in the heliosphere explain the observed amplitude of the CMB quadrupole?

Key findings

• The paper proposes that the CMB quadrupole moment may arise from geometric distortions in the heliosheath due to the asymmetric termination shock.
• Temporal variations in solar wind pressure could lead to time-varying distortions that affect the CMB's multipole moments.
• Observations from the Voyager spacecraft of abrupt changes in plasma and electromagnetic fields at the termination shock support the existence of dynamic, structured boundaries.
• The model speculates that heliosheath processes could imprint features on the small-scale CMB angular power spectrum.
• The study suggests that local solar system phenomena may contribute to the observed CMB anisotropy, challenging the standard cosmological interpretation.
• No quantitative prediction of the quadrupole amplitude is provided, but the mechanism is presented as a plausible alternative explanation.