The bullet would fall straight through the Earth's crust. On the surface, the vibration would quickly die down. But far below, the bullet would be crushing and vaporizing the mantle in front of it as it fell. It would blast the material out of the way with powerful shockwaves, leaving a trail of superhot plasma behind it. This would be something never before seen in the history of the universe: an underground shooting star.
子弹会直直地穿透地壳。地表的震动很快就会消散，不过在地下极深处，随着子弹的下落，它会挤压并气化前方的地幔。子弹周围的物质会被强大的冲击波炸开，尾部留下一长串极其炽热的等离子体。这是宇宙有史以来从未出现过的现象：一颗地下流星。
Eventually, the bullet would come to rest, lodged in the nickel-iron core at the center of the Earth. The energy delivered to the Earth would be massive on a human scale, but the planet would barely notice. The bullet's gravity would affect only the rock within a few dozen feet of it; while it's heavy enough to fall through the crust, its gravity alone wouldn't be strong enough to crush the rock very much.
最终子弹会慢慢停下来，卡在地球中央铁镍核心中的某个地方。子弹传递给地球的能量在人类看来非常庞大，但对于地球来说就是九牛一毛了。子弹的重力只会影响它周围十几米范围内的岩石。虽然它的重量大到足以让它穿过地壳，但还是不够把石头压穿。
The hole would close up, leaving the bullet forever out of anyone's reach.4 Eventually, the Earth would be consumed by the aging, swollen Sun, and the bullet would reach its final resting place at the Sun's core.
子弹留下的孔会闭合，把子弹永远掩埋在任何人都不可能挖得到的地方。4最终地球会被年老的太阳吞没，而这颗子弹最后的安息之所将是太阳的核心之中。
The Sun isn't dense enough to become a neutron star itself. After it swallows the Earth, it will instead go through some phases of expansion and collapse, and will eventually settle down, leaving behind a small white dwarf star with the bullet still lodged in the center. Someday, far in the future-when the universe is thousands of times older than it is today-that white dwarf will cool and fade to black.
太阳本身的质量并不足以使地球变为中子星。在它吞没地球后，它会经历一系列的膨胀和坍缩，最终一切都安宁下来，只留下一颗小小的白矮星，而那颗子弹还留在中央。在遥远的某一天——当宇宙的年龄变成现在的几千倍时——那颗白矮星会冷却成为黑矮星。
That answers the question of what would happen if the bullet were fired into the Earth. But what if we could keep it near the surface?
至此我们回答了如果子弹射入地球内部会发生什么。那么如果我们设法让它留在地表呢？