《那些古怪又讓人憂心的問題》第25期:閃電(3)

Q. What if you were changing the light atthe top of a radio tower, and lightning struck? Or what if you were doing abackflip? Or standing in a graphite field? Or looking straight up at the bolt?

Q．如果你在廣播信號塔上更換燈泡時被雷擊了會怎麼樣？如果你在做後空翻的時候被擊中了呢？或者站在一片石墨地上呢？又或者擡頭盯着閃電看呢？

Q. What would happen if lightning struck abullet in midair?

Q．閃電擊中飛行途中的子彈會發生什麼？

A. THE BULLET WON'T AFFECT the path thelightning takes. You'd have to somehow time the shot so the bullet was in themiddle of the bolt when the return stroke happened.

A．子彈不會影響閃電經過的路徑。你必須精確地把握好時機，這樣才能讓子彈在閃電回擊的那一刻恰好位於閃電路徑之中。

The core of a lightning bolt is a fewcentimeters in diameter. A bullet fired from an AK-47 is about 26 mm long andmoves at about 700 millimeters every millisecond.

閃電路徑的核心部分直徑大約爲幾釐米，而AK-47步槍使用的子彈長度約爲26毫米，每毫秒能夠前進約700毫米。

The bullet has a copper coating over a leadcore. Copper is a fantastically good conductor of electricity, and much of the20,000 amps could easily take a shortcut through the bullet.

子彈的鉛質核心外面包了一層銅質外殼。銅是電的優良導體，2萬安培電流中的大部分都將輕易地流過子彈走捷徑。

Surprisingly, the bullet would handle itpretty well. If it were sitting still, the current would quickly heat and meltthe metal. But since it would be moving along so quickly, it would exit thechannel before it could be warmed by more than a few degrees. It would continueon to its target relatively unaffected. There would be some curiouselectromagnetic forces created by the magnetic field around the bolt and thecurrent flow through the bullet, but none of the ones I examined would changethe overall picture very much.

令人驚訝的是，閃電並不會對子彈造成什麼傷害。如果子彈靜止不動，那麼通過的電流將會很快加熱並熔化子彈上的金屬材料。但由於子彈的飛行速度太快，它在離開閃電通道的時候自身僅被加熱了幾攝氏度，子彈會幾乎不受任何影響地繼續飛向目標。閃電周圍的磁場和流過子彈的電流會產生一些有意思的電磁力，但所有我檢驗過的電磁力中沒有一個會顯著影響最後的結果。

1 Or a real one, for that matter.

1或者滾一個真的球……

2 Paleontologists estimate he stood nearly 5meters tall at the shoulder.

古生物學家估計他直立時肩膀處有將近5米高。

3 While it's called a “return stroke,”charge is still flowing downward. However, the discharge appears to propagateupward. This effect is similar to how when a traffic light turns green, thecars in front start moving, then the cars in back, so the movement appears tospread backward.

雖然這個過程又被稱爲回擊，但電荷是向下流動的，然而放電看上去是向上傳播的。這有點像當交通信號燈從紅燈變爲綠燈時，前面的汽車開始移動，然後纔是後面的汽車，看上去汽車運動是向後傳播的。

4 For safety reasons, do not use a realsphere.

出於安全原因，不要用真的球。

Q. Would it be possible to stop a volcanoeruption by placing a bomb (thermobaric or nuclear) underneath the surface?

Q．在火山地面以下的地方安置溫壓彈或者核彈，能夠阻止火山爆發嗎？

-Aaron Smith

——阿龍•史密斯