摘要:
   In this talk, I will give an overview of the current status of Big-Bang Theory and its observational supports and highlight some of the unsolved problems that exist in the current Lambda-CDM paradigm. These include the Big-Bang nucleosynthesis,  cosmic microwave background radiation measurement, gravitational lensing, inflation scenario and tests, and intergalactic medium. I will discuss the current measurements from modern telescopes and their physical implication for the early Universe. Finally, I will discuss the following question in physics perspective: what we will never know?