RELATIVISTIC BASEBALL
相对论棒球
Q. What would happen if you tried to hit a baseball pitched at 90 percent the speed of light?
如果棒球被以0.9倍光速掷出会产生什么后果？——艾伦?麦克马尼斯
Let 8217;s set aside the question of how we got the baseball moving that fast. We 8217;ll suppose it 8217;s a normal pitch, except in the instant the pitcher releases the ball, it magically accelerates to 0.9c. From that point onward, everything proceeds according to normal physics.
让我们先不要去纠结棒球是如何加速到这么快的，假设这只是一次普通的投球，但在投手掷出球的那一刻，棒球被魔法加速到了0.9倍光速。从那一刻起，正常的物理规律再度开始发挥作用。
THE ANSWER TURNS OUT to be “a lot of things,” and they all happen very quickly, and it doesn 8217;t end well for the batter (or the pitcher). I sat down with some physics books, a Nolan Ryan action figure, and a bunch of videotapes of nuclear tests and tried to sort it all out. What follows is my best guess at a nanosecond-by-nanosecond portrait.
是“会发生很多事情”，而且这些事情发生在相当短的一段时间内，对于击球手（或投球手）来说他们的结局有些悲惨。为了弄清楚到底会发生什么，我找来了一些物理书、一个诺兰?莱恩1人偶，以及一堆核爆试验的录像带。接下来我将向你展示尽我所能推理出来的纳秒级事件记录。
The ball would be going so fast that everything else would be practically stationary. Even the molecules in the air would stand still. Air molecules would vibrate back and forth at a few hundred miles per hour, but the ball would be moving through them at 600 million miles per hour. This means that as far as the ball is concerned, they would just be hanging there, frozen. The ideas of aerodynamics wouldn 8217;t apply here. Normally, air would flow around anything moving through it. But the air molecules in front of this ball wouldn 8217;t have time to be jostled out of the way. The ball would smack into them so hard that the atoms in the air molecules would actually fuse with the atoms in the ball 8217;s surface. Each collision would release a burst of gamma rays and scattered particles.
棒球的速度实在是太快，以至于其他任何东西看上去都像静止了一样。即使是来回振动速度可达每小时上千千米的空气分子，相比起移动速度高达每小时9亿千米的棒球，看上去也会像冻结在空中一样。空气动力学在此时已经不起作用了。正常情况下，空气会流过运动物体的表面，但此时棒球前方的空气分子根本没有时间躲开棒球，棒球会直直地撞上这些空气分子，其力度之大甚至能使棒球表面空气分子的原子核发生聚变反应。每一次碰撞都会释放出一股伽马射线暴和四处飞散的粒子。
These gamma rays and debris would expand outward in a bubble centered on the pitcher 8217;s mound. They would start to tear apart the molecules in the air, ripping the electrons from the nuclei and turning the air in the stadium into an expanding bubble of incandescent plasma. The wall of this bubble would approach the batter at about the speed of light-only slightly ahead of the ball itself.
这些伽马射线和碎屑会形成一个以投手丘为中心不断扩大的气泡，它们会扯碎空气中的分子，把电子从原子核里剥离出来，整个球场内的空气都会变成不断膨胀的炽热等离子泡。这个等离子泡的边缘会以接近光速的速度（比棒球本身的速度略快一些）向击球手飞去。
The constant fusion at the front of the ball would push back on it, slowing it down, as if the ball were a rocket flying tail-first while firing its engines. Unfortunately, the ball would be going so fast that even the tremendous force from this ongoing thermonuclear explosion would barely slow it down at all. It would, however, start to eat away at the surface, blasting tiny fragments of the ball in all directions. These fragments would be going so fast that when they hit air molecules, they would trigger two or three more rounds of fusion.
棒球前方不断发生的聚变反应所产生的反作用力会把棒球向后推，慢慢地降低它的速度，就像一枚引擎点燃、尾部还在朝前飞的火箭。不幸的是，棒球的速度实在是太快，以至于这持续不断的热核反应所产生的巨大反作用力，仍然不足以使棒球的速度降低多少。然而它还是会不停地侵蚀棒球的表面，把棒球产生的细小碎屑向四面八方喷射出去。这些飞散的碎屑一旦撞上别的空气分子，其本身的巨大速度又将引发两到三轮新的核聚变。
After about 70 nanoseconds the ball would arrive at home plate. The batter wouldn 8217;t even have seen the pitcher let go of the ball, since the light carrying that information would arrive at about the same time the ball would. Collisions with the air would have eaten the ball away almost completely, and it would now be a bullet-shaped cloud of expanding plasma (mainly carbon, oxygen, hydrogen, and nitrogen) ramming into the air and triggering more fusion as it went. The shell of x-rays would hit the batter first, and a handful of nanoseconds later the debris cloud would hit.
在棒球被掷出70纳秒后，它已经飞到了本垒板前。此时击球手甚至都还没看到棒球从投球手手中掷出，因为传递这一信息的光几乎是和棒球本身同一时刻到达击球手面前的。与空气之间的持续碰撞几乎已经把整个棒球侵蚀殆尽了，这时出现在击球手面前的是一团子弹形状的、不断膨胀的等离子云（主要成分是碳、氧、氢和氮），撞击着空气，引发更多的聚变反应。最先击中击球手的是外层的X射线，几纳秒后碎屑云也将接踵而至。
When it would reach home plate, the center of the cloud would still be moving at an appreciable fraction of the speed of light. It would hit the bat first, but then the batter, plate, and catcher would all be scooped up and carried backward through the backstop as they disintegrated. The shell of x-rays and superheated plasma would expand outward and upward, swallowing the backstop, both teams, the stands, and the surrounding neighborhood-all in the first microsecond.
即使在飞抵本垒板后，等离子云团的核心部分仍将以接近光速的速度前进。它会先撞上球棒，但转瞬间击球手、本垒板和接球手都将被云团夹带着，撞穿后面的挡球网，同时解体。外层的X射线和炽热的等离子气体将继续向上向外扩张，将挡球网、双方队伍、看台以及周围的居民区一一吞没——而这些都将发生在球被掷出后的第一个毫秒内。
Suppose you 8217;re watching from a hilltop outside the city. The first thing you would see would be a blinding light, far outshining the sun. This would gradually fade over the course of a few seconds, and a growing fireball would rise into a mushroom cloud. Then, with a great roar, the blast wave would arrive, tearing up trees and shredding houses.
如果你在城市外一个小山丘上观看这场赛事，你先会看到一股耀眼的光线，其亮度远远超过太阳。几秒钟后这股强光慢慢消散，随之而来的是一个不断变大的火球升入高空，形成一个蘑菇云。随后冲击波会伴随着一声巨响呼啸而来，摧毁沿途的树木和建筑。
Everything within roughly a mile of the park would be leveled, and a firestorm would engulf the surrounding city. The baseball diamond, now a sizable crater, would be centered a few hundred feet behind the former location of the backstop.
离球场中心大约一两千米范围之内的所有区域都会被夷为平地，火焰风暴会吞噬整座城市。原先的那个棒球场所在地将会留下一个大坑，坑的中心在挡球网后面100多米的地方。
Major League Baseball Rule 6.08(b) suggests that in this situation, the batter would be considered “hit by pitch,” and would be eligible to advance to first base.
根据职业棒球大联盟规则的6.08（b）条款，这个球将被判定为“触身球”，击球手将被保送上一垒。
After I initially published this article, MIT physicist Hans Rinderknecht contacted me to say that he 8217;d simulated this scenario on their lab 8217;s computers. He found that early in the ball 8217;s flight, most of the air molecules were actually moving too quickly to cause fusion, and would pass right through the ball, heating it more slowly and uniformly than my original article described.
在我最初发表这篇文章之后，麻省理工学院的物理学家汉斯?林德克奈彻特联系我说，他在他们实验室的计算机上模拟了这一场景，他发现在棒球刚飞出去的一小段时间内，绝大多数空气分子的移动速度甚至高到无法产生聚变，它们会直接穿透棒球飞出。较之我原先文章所描述的结果，空气加热的速度会更慢，同时也更均匀。