黏滞性流体与宇宙年龄问题
发布时间：2018-08-31 14:26
【摘要】：在宇宙的演化过程当中,经历了暴胀、辐射以及物质为主时期.如果宇宙现在仍处于物质为主时期,那么理论上所得到的宇宙年龄大概是在80～100亿年左右.另一方面,人们测得一些古老星团的年龄超过了110亿年,由此可见,理论预言与观测结果不相符合,这就是宇宙的年龄问题.当前的观测表明宇宙正处于加速膨胀时期,人们通常将加速的原因归结于宇宙中存在着一种被称为暗能量的物质组分.人们进一步发现由于这种组分可以使理论上预言的宇宙年龄变大,从而缓解了宇宙年龄问题.可是,最新的观测表明,仍有一些天体的年龄比预言的宇宙年龄要大,比如说类星体APM08279+5255,它在红移等于3.91时的年龄大概是21亿年,超过了当时的宇宙年龄.事实上,通常人们在研究宇宙学中,仅仅考虑了理想流体这一简单模型,而该模型可能过于简单.因此,本文将考虑带有黏滞性的流体.通过引入黏滞性,宇宙的年龄问题被进一步缓解了.尽管,本文考虑一类被称为Ricci暗能量的模型,但是所得到的结论可以推广和应用到各种暗能量模型中.
[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.
【作者单位】： 上海师范大学天体物理联合研究中心;
【基金】：国家自然科学基金(批准号:11105091,11047138) 国家教育基金(编号:2009312711004) 上海市自然科学基金(批准号:10ZR1422000)资助项目
【分类号】：P159
，
本文编号：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.
【作者单位】： 上海师范大学天体物理联合研究中心;
【基金】：国家自然科学基金(批准号:11105091,11047138) 国家教育基金(编号:2009312711004) 上海市自然科学基金(批准号:10ZR1422000)资助项目
【分类号】：P159
，
本文编号：2215265
本文链接：https://www.wllwen.com/kejilunwen/tianwen/2215265.html
