Transcript · English → Chinese
Understanding Our Solar System's Movement
每秒钟， 你就会移动约二百三十
公里，穿行于银河系中，
而你从未察觉。
我们把太阳系想象成一个时钟， 行星围绕着一颗
固定不动的太阳运转。但太阳并未
停在原处。
它正绕着银河系的中心飞驰， 携带着
每一颗行星。因此一年之后，
地球回到了其 轨道上的同一点，
但轨道本身已经移动。你 离起点已超过七十
亿公里。
绕银河系一周大约需要两 亿三千万
年。
上一次太阳处于这里时， 最早的恐龙才刚刚
出现。 而我们并非毫无防护地旅行。
太阳风以大约每小时一 百万英里的速度向外流动，
将巨大的气泡吹胀，笼罩着
整个太阳系，这就是日球层。
它偏转了约四分之三的 原本会抵达我们的银河宇宙射线。
否则会抵达我们这里。它的边缘 远在
旅行者一号， 于1977年发射，花了
35年才抵达那里。 而令人惊讶的是：
大多数图示都在前方画出冲击波， 就像一艘
破水而行的船。
其实并没有。我们在星际气体中漂流 ， 速度只有
区区
每秒23公里。
速度太慢，无法形成冲击波，
只能形成柔和的弓形波。
所以下次你仰望天空时，请记住，
你正身处一个气泡中， 它正穿行于这片
银河系， 而你从未感觉到它在移动。
End of transcript · 257 words · machine translated
Original transcript (English)
Every second, you move about two hundred and thirty kilometers through the galaxy, and you never feel it. We picture the solar system like a clock, planets circling a sun that stays put. But the sun does not
stay put. It is racing around the center of the Milky Way, carrying every planet with it. So after one year, Earth is back at the same point in its orbit, but the orbit itself has moved. You are more than seven
billion kilometers from where you started. One lap of the galaxy takes about two hundred and thirty million years. The last time the sun was here, the first dinosaurs were only just appearing. And we do not travel unprotected.
The sun's wind streams outward at around a million miles an hour, inflating a vast bubble around the entire solar system, the heliosphere. It deflects roughly three-quarters of the galactic cosmic rays that would otherwise reach us. Its edge is so far out that
Voyager One, launched in nineteen seventy-seven, needed thirty-five years to get there. And here is the surprise: Most diagrams draw a shockwave out front, like a boat cutting through water. There isn't one. We drift through the interstellar gas at
just twenty-three kilometers per second. Too slow for a shock, only a gentle bow wave. So the next time you look up, remember,
you are riding inside a bubble, sweeping through the galaxy, and you have never once felt it move.
