space exploration
On September 14, 2015, LIGO detected gravitational waves from the merger of two black holes 29 and 36 times the mass of the Sun. This is the first time for human beings to divectly detect such waves and the first observation of a binary black hole merger. What are gravitational waves? What are black holes? How do they connect each other? What happens when black holes collide? Author will explain these for you.
Will our sun become a black hole? No. Stars like the Sun just are not massive enough to become black hole. Instead, in several billion years, the Sun will cast off its outer layer, and its core will form a white dwarf, a dense ball of carbon and oxygen that no longer produces nuclear energy, which still shines because it is very hot. A typical white dwarf is about as massive as the Sun, but only as big as the Earth, which is one percent of the Sun’s present diameter.
Unitarity is required by quantum mechanics for the dynamics of any closed systems, i.e., information is conserved for closed systems. The black hole information loss conflicts to the unitarity, which indicates the impossibility of unifying quantum mechanics with gravity. In this paper, we review the origin of the puzzle and the possible solutions.
