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How the First Stars in the Universe Came into
Existence Researchers believe that our universe began with the Big Bang(宇宙大爆炸)about 13 billion years ago，and that soon after that event，matter began to form as small dust grains and gases．How the first stars formed from this dust and gas has been a burning question for years，but a state of-the-art computer simulation now offers the most detailed picture yet of how these first stars in the universe came into existence． The composition of the early universe was quite different from that of today，and the physics that governed the early universe were also somewhat simpler．Dr．Naoki Yoshida and colleagues in Japan and the U．S．incorporated these conditions of the early universe，sometimes referred to as the“cosmic dark ages，”to simulate the formation of an astronomical object that would eventually shine its light into this darkness． The result is a detailed description of the formation of a protostar(原恒星)-the early stage of a massive primordial(原始的)star of our universe-and the researchers'computer simulation sets the bar for further investigation into the star formation process．The question of how the first stars evolved is so important because their formations and eventual explosions provided the seeds for subsequent stars to come into being． According to their simulation，gravity acted on minute density variations in matter，gases，and the mysterious“dark matter”of the universe after the Big Bang in order to form this early stage of a star-a protostar with a mass of just one percent of our sun．The simulation reveals how pre-stellar(前恒星的) gases would have actually evolved under the simpler physics of the early universe to form this protostar． Dr．Yoshida's simulation also shows that the protostar would likely evolve into a massive star capable of synthesizing(合成)heavy elements，not just in later generations of stars，but soon after the Big Bang． Their simulation of the birth of a protostar in the early universe signifies a key step toward the ambitious goal of piecing together the formation of an entire primordial star and of predicting the mass and properties of these first stars of the universe．More powerful computers，more physical data，and an even larger range will be needed for further calculations and simulations，but these researchers hope to eventually extend this simulation to the point of nuclear reaction initiation-when a stellar(星球的)object be comes a true star． |