1·But sunlight is not the only way to heat an astronomical body. Gravity can do it, too.
但太阳光并非让一个天体热起来的唯一途径，引力也可以。
2·The so-called "food" is a celestial body that was another celestial body or its Heiying Yanzhe all or part of the astronomical scene.
所谓"食"就是指一个天体被另一个天体或其黑影全部或部分掩遮的天文景象。