A branch of physical science that is concerned with the study of matter and energy and how they interact.
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白矮星已冷却和变暗后留下的冷稠密气体的质量。
一种使用一种化学反应,使电力设备。燃料使用单元格在航天飞机,在他们创建电力通过结合氧和氢。