A 400-kilometer wide impact basin is visible near the image center, delineated by deep scarps that drop sharply to the crater floor.

一个400公里宽的冲击坑在图近中间处可见，是被深深的碎片直接掉落在表壳所勾勒出来。

youdao

Scientists think such inverted craters form when an impact basin fills with sediment and the material around that sediment gets eroded away.

科学家们认为，当撞击盆地被沉积物所填满，而沉积物周围的部分逐渐被侵蚀殆尽时，就会形成了类似这样的颠倒陨石坑。

youdao

This observation from NASA's Mars Reconnaissance Orbiter shows the floor of a large impact crater in the southern highlands, north of the giant Hellas impact basin.

这幅来自NASA火星轨道观察器的图像显示了位于火星南方高地巨大的Hellas撞击盆地北侧地表上的一个大撞击坑。

youdao

Now fast-forward to 2013, where in the past few weeks the Curiosity rover has been drilling into some different rocks half a planet away, inside a deep basin formed by the Gale impact crater.

CNN: Have a drink on Mars