本题目来源于试卷: Astrophysics and Cosmology，类别为 IB物理学
[问答题]
Explain what the 2.7-K cosmic microwa3/j tj5 hnr,xpve backgt djy4orr: qj2 w3vl/(round radiation is. Where does it come from? Why is its temperature now so d lyw3t vr2q/:jrj(4 olow?
参考答案:
The material contained in the universe is at some average temperature and, thus, it radiates a blackbody spectrum that is characteristic of this temperature. This temperature is now so low because of the expansion of the universe. When the universe was extremely small and the sum total energy of the universe was trapped in that extremely small volume, the average temperature of the universe was amazingly high. As this energy has been spread out over our expanding universe, the average temperature has decreased to its current low level.
本题详细解析:
暂无
| 
