黏滯性流體與宇宙年齡問題
發(fā)布時間：2018-08-31 14:26
【摘要】：在宇宙的演化過程當中,經(jīng)歷了暴脹、輻射以及物質(zhì)為主時期.如果宇宙現(xiàn)在仍處于物質(zhì)為主時期,那么理論上所得到的宇宙年齡大概是在80～100億年左右.另一方面,人們測得一些古老星團的年齡超過了110億年,由此可見,理論預(yù)言與觀測結(jié)果不相符合,這就是宇宙的年齡問題.當前的觀測表明宇宙正處于加速膨脹時期,人們通常將加速的原因歸結(jié)于宇宙中存在著一種被稱為暗能量的物質(zhì)組分.人們進一步發(fā)現(xiàn)由于這種組分可以使理論上預(yù)言的宇宙年齡變大,從而緩解了宇宙年齡問題.可是,最新的觀測表明,仍有一些天體的年齡比預(yù)言的宇宙年齡要大,比如說類星體APM08279+5255,它在紅移等于3.91時的年齡大概是21億年,超過了當時的宇宙年齡.事實上,通常人們在研究宇宙學(xué)中,僅僅考慮了理想流體這一簡單模型,而該模型可能過于簡單.因此,本文將考慮帶有黏滯性的流體.通過引入黏滯性,宇宙的年齡問題被進一步緩解了.盡管,本文考慮一類被稱為Ricci暗能量的模型,但是所得到的結(jié)論可以推廣和應(yīng)用到各種暗能量模型中.
[Abstract]:During the evolution of the universe, it underwent a period of inflation, radiation and matter. If the universe is still dominated by matter, the theoretical age of the universe is about 80 to 10 billion years. On the other hand, some ancient clusters are over 11 billion years old, which shows that the theoretical prediction does not accord with the observational results. This is the age problem of the universe. Current observations indicate that the universe is in a period of accelerating expansion, and the reason for acceleration is usually attributed to the existence of a component of matter called dark energy in the universe. It is further found that the age of the universe predicted in theory can be increased by this component, which alleviates the problem of the age of the universe. However, recent observations show that some objects are still older than the predicted cosmic age, such as the quasar APM08279 5255, which is about 2.1 billion years old when the redshift equals 3.91, exceeding the age of the universe at that time. In fact, in the study of cosmology, only the simple model of ideal fluid is considered, which may be too simple. Therefore, the fluid with viscous property will be considered in this paper. By introducing viscosity, the age problem of the universe is further alleviated. Although we consider a class of models called Ricci dark energy, the results can be generalized and applied to various dark energy models.
【作者單位】： 上海師范大學(xué)天體物理聯(lián)合研究中心;
【基金】：國家自然科學(xué)基金(批準號:11105091,11047138) 國家教育基金(編號:2009312711004) 上海市自然科學(xué)基金(批準號:10ZR1422000)資助項目
【分類號】：P159
，
本文編號：2215265
[Abstract]:During the evolution of the universe, it underwent a period of inflation, radiation and matter. If the universe is still dominated by matter, the theoretical age of the universe is about 80 to 10 billion years. On the other hand, some ancient clusters are over 11 billion years old, which shows that the theoretical prediction does not accord with the observational results. This is the age problem of the universe. Current observations indicate that the universe is in a period of accelerating expansion, and the reason for acceleration is usually attributed to the existence of a component of matter called dark energy in the universe. It is further found that the age of the universe predicted in theory can be increased by this component, which alleviates the problem of the age of the universe. However, recent observations show that some objects are still older than the predicted cosmic age, such as the quasar APM08279 5255, which is about 2.1 billion years old when the redshift equals 3.91, exceeding the age of the universe at that time. In fact, in the study of cosmology, only the simple model of ideal fluid is considered, which may be too simple. Therefore, the fluid with viscous property will be considered in this paper. By introducing viscosity, the age problem of the universe is further alleviated. Although we consider a class of models called Ricci dark energy, the results can be generalized and applied to various dark energy models.
【作者單位】： 上海師范大學(xué)天體物理聯(lián)合研究中心;
【基金】：國家自然科學(xué)基金(批準號:11105091,11047138) 國家教育基金(編號:2009312711004) 上海市自然科學(xué)基金(批準號:10ZR1422000)資助項目
【分類號】：P159
，
本文編號：2215265
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