Just like visible light, x-rays are less likely to penetrate denser materials.

类似于可见光，X线难以穿过密度高的物体。

Or is it one of the prize rocky planets that's mostly heavier, more dense material?

还是说它是一颗质量更重，密度更大的岩质行星？

In contrast, the sharp bright white areas are where the dense bone material blocks photons from getting through.

与之相反，明亮的白色区域是密度较高的骨质，它们可以阻挡光子透过。

Just going on intuition, you might think, " Okay, when a moving thing, cruising along, hits a denser material, it's gonna get bogged down."

凭直觉，你可能会想，“好吧，当一个移动的东西运动时，碰到一个密度更大的物质，它会受到阻碍。”

And a fourth source of heat is from dense material like iron and nickel sinking to the center of the Earth, which warms things up due to friction.

第四个来源是铁和镍等密度大的物质向地球中心下沉时，由于它们和物质之间的摩擦而增加温度。

At night, dense materials release the heat they absorbed during the day, which is causing a dramatic increase in nighttime temperatures and stifling our chance to cool down.

到了晚上，致密物质释放出它们在白天吸收的热量，这导致夜间温度急剧升高，扼杀了我们降温的机会。