From long ago, by an established tradition that can be traced to the hypothesis of immanuel kant and the marquis de laplace, astronomers have assumed that stars develop out of a scattered, diffuse medium of gas and dust . 很长时间以来,天文学家承袭了可以追溯至康德和拉普拉斯假说所建立的概念,认为恒星由散布在空中的弥漫气尘物质演变而来。