{"query": "Why is it believed the universe began at a particular time?", "pos": "According to a number of earlycosmologies and the Jewish/Christian/Muslim tradition, the universe started at a finite, and not very distant,time in the past. One argument for such a beginning was the feeling that it was necessary to have “First Cause”to explain the existence of the universe. (Within the universe, you always explained one event as being causedby some earlier event, but the existence of the universe itself could be explained in this way only if it had somebeginning.) Another argument was put forward by St. Augustine in his book The City of God. He pointed out\nthat civilization is progressing and we remember who performed this deed or developed that technique."}
{"query": "Could you elucidate on the intricate procedure of stellar constitution?", "pos": "Andeven then it was a long time before the implications of the theory for massive stars were understood.To understand how a black hole might be formed, we first need an understanding of the life cycle of a star. A star isformed when a large amount of gas (mostly hydrogen) starts to collapse in on itself due to its gravitational attraction. Asit contracts, the atoms of the gas collide with each other more and more frequently and at greater and greater speeds –the gas heats up. Eventually, the gas will be so hot that when the hydrogen atoms collide they no longer bounce offeach other, but instead coalesce to form helium. The heat released in this reaction, which is like a controlled hydrogenbomb explosion, is what makes the star shine."}
{"query": "Black hole existence evidence?", "pos": "the body that has collapsed must be lost when a black hole is formed, because afterward all we can possibly measureabout the body is its mass and rate of rotation. The significance of this will be seen in the next chapter.Black holes are one of only a fairly small number of cases in the history of science in which a theory was developed ingreat detail as a mathematical model before there was any evidence from observations that it was correct. Indeed, thisused to be the main argument of opponents of black holes: how could one believe in objects for which the onlyevidence was calculations based on the dubious theory of general relativity?"}
