Introduction

Recent observations indicate that the Universe is not transparent but partially opaque due to absorption of light by ambient cosmic dust. This implies that the current cosmological model valid for the transparent universe must be modified for the opaque universe.

Objectives

The paper studies a scenario of the evolution of the Universe when the cosmic opacity steeply rises with redshift, because the volume of the Universe was smaller and the cosmic dust density was higher in the previous epochs. In this case, the light-matter interactions become important, because cosmic opacity produces radiation pressure that counterbalances gravitational forces.

Methods

The radiation pressure due to cosmic opacity is evaluated and incorporated into the Friedmann equations, which describe cosmic dynamics. The equations are based on the conformal FLRW metric and are consistent with observations of the cosmological redshift as well as time dilation. Using astronomical observations of basic cosmological parameters, the solution of the modified Friedmann equations is numerically modelled.

Results

The presented model predicts a cyclic expansion/contraction evolution of the Universe within a limited range of scale factors with no Big Bang. The redshift of the Universe with the minimum volume is about 15–17. The model avoids dark energy and removes several fundamental tensions of the standard cosmological model. In agreement with observations, the modified Friedmann equations predict the existence of very old mature galaxies at high redshifts and they do not limit the age of stars in the Universe. The new model is consistent with theory of cosmic microwave background as thermal radiation of cosmic dust.

Conclusion

The paper demonstrates that considering light-matter interactions in cosmic dynamics is crucial and can lead to new cosmological models essentially different from the currently accepted ΛCDM model.

中文翻译：

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基于共形 FLRW 度量考虑弗里德曼方程中的光与物质相互作用

介绍

最近的观察表明，由于周围的宇宙尘埃吸收光，宇宙不是透明的，而是部分不透明的。这意味着当前适用于透明宇宙的宇宙学模型必须针对不透明宇宙进行修改。

目标

该论文研究了宇宙不透明度随红移急剧上升时宇宙演化的情景，因为在之前的时代宇宙体积更小，宇宙尘埃密度更高。在这种情况下，光与物质的相互作用变得很重要，因为宇宙的不透明性会产生抵消引力的辐射压。

方法

对宇宙不透明度引起的辐射压进行了评估，并将其纳入描述宇宙动力学的弗里德曼方程中。这些方程基于共形 FLRW 度量，并且与宇宙红移和时间膨胀的观测结果一致。利用对基本宇宙学参数的天文观测，对修改后的弗里德曼方程的解进行数值建模。

结果

所提出的模型预测宇宙在有限的比例因子范围内没有大爆炸的循环膨胀/收缩演化。最小体积的宇宙红移约为15-17。该模型避免了暗能量并消除了标准宇宙学模型的几个基本张力。与观测结果一致，修正后的弗里德曼方程预测存在高红移的非常古老的成熟星系，并且它们不限制宇宙中恒星的年龄。新模型符合宇宙微波背景作为宇宙尘埃热辐射的理论。

结论

该论文表明，在宇宙动力学中考虑光与物质的相互作用是至关重要的，并且可以产生与目前接受的 ΛCDM 模型本质上不同的新宇宙学模型。