400-1816-180
请填写手机号
12G备考资料
播放一次
- 播放一次
- 播放三次
- 循环播放
正常语速
- 0.8倍语速
- 正常语速
- 1.2倍语速
- 1.5倍语速
- 1.8倍语速
-
1
This is Scientific American 60-Second Science. I'm Julia Rosen.
这是科学美国人60秒科学。我是Julia Rosen.
-
2
Other rocky planets in our solar system show a common feature: within giant craters caused by impacts there's evidence of volcanic activity.
我们太阳系中的其他岩石行星显示出一个共同的特征：由撞击引起的巨大陨石坑内有火山活动的证据。
-
3
Which made scientists wonder-can big impacts actually cause volcanic eruptions?
这让科学家们感到奇怪 - 重大影响实际上会导致火山爆发吗？
-
4
And has that scenario ever happened here?
这种情况曾经发生在这里吗？
-
5
To find out, scientists went to one of the few massive craters on Earth not erased by plate tectonics: the Sudbury crater in Canada.
为了找到答案，科学家们去了地球上为数不多的巨大陨石坑之一，这些陨石坑没有被板块构造所抹去：加拿大的萨德伯里陨石坑。
-
6
"Sudbury is a 1.85-billion-year-old impact structure."
“萨德伯里是一个拥有18.5亿年历史的撞击结构。”
-
7
Teresa Ubide, a geochemist at the University of Queensland in Australia.
Teresa Ubide，澳大利亚昆士兰大学的地球化学家。
-
8
"Sudbury was generated when a bolide of 10 to 15 kilometers in diameter hit Earth...and what happened was it obviously generated a large basin and also it melted the...crust on top of the Earth at that time.
“萨德伯里是在直径10到15公里的火流星撞击地球时产生的...而且发生的事情显然是它产生了一个大盆地，并且当时它还融化了地壳顶部的地壳。
-
9
And generated a massive melt pool, 2.5 kilometers in depth."
并形成了一个2.5公里深的巨大熔池。"
-
10
But Ubide and her colleagues found that the impact did more than that: it also seems to have triggered eruptions of magma that came from deep in the mantle.
但是Ubide和她的同事们发现这种影响不仅如此：它似乎还引发了来自地幔深处的岩浆喷发。
-
11
The evidence lies in the fact that the chemistry of the lava that erupted at Sudbury changed over time.
证据在于，萨德伯里爆发的熔岩的化学性质随着时间的推移而发生变化。
-
12
At first, it matched the surface rocks, suggesting it was just from local melting.
起初，它与表面岩石相匹配，表明它只是来自局部融化。
-
13
But as the eruptions continued, the lava appeared to come from deep in the mantle, suggesting the impact stirred things up inside the Earth.
但随着火山喷发的持续，熔岩似乎来自地幔的深处，这表明这种影响会激起地球内部的影响。
-
14
No one knows yet exactly how the impact could have sparked a prolonged episode of volcanism.
没有人确切知道这种影响究竟是如何引发长期的火山活动。
-
15
One possible explanation is that after the object smashed into the surface, the crust would have rebounded upward, temporarily decompressing the mostly solid mantle and causing it to melt and produce magma.
一种可能的解释是，在物体撞击表面后，地壳会向上反弹，暂时使大部分固体地幔减压并使其熔化并产生岩浆。
-
16
The results are in the Journal of Geophysical Research: Planets.
结果发表在“地球物理研究杂志：行星”杂志上。
-
17
It's hard to know if the same thing happened on other planets, Ubide says.
Ubide说，很难知道其他星球上是否发生了同样的事情。
-
18
In many spots in the solar system it looks like volcanism happened much longer after the impact than what she saw at Sudbury.
在太阳系的许多地方，看起来火山活动发生的影响要比她在萨德伯里看到的要长得多。
-
19
But without material to examine directly, we can't be sure.
但是没有材料可以直接检查，我们无法确定。
-
20
Nevertheless, these results do help explain a mysterious chapter in Earth's own history.
然而，这些结果确实有助于解释地球自身历史中的一个神秘篇章。
-
21
Most major impacts on our planet happened about four billion years ago, when the solar system was still settling down.
对我们星球的大多数重大影响发生在大约40亿年前，当时太阳系仍在稳定下来。
-
22
But there's no crust around from that time, suggesting the entire planet got a makeover soon after.
但是从那时起就没有地壳了，这表明整个地球很快就会改头换面。
-
23
"We're suggesting that impacts are able to not only generate the crater, but also, generate melting deeper, say, in the mantle, and bring to the surface material from depth.
“我们建议撞击不仅能够产生陨石坑，而且能够在地幔中产生更深的熔化，并从深处带来表面材料。
-
24
So actually, recycle and resurface."
所以实际上，回收并重新浮出水面。"
-
25
It seems the pummeling that Earth endured in the beginning may have triggered volcanic activity that helped wipe away the evidence of those very impacts.
看起来地球在开始时遭受的打击可能引发了火山活动，这有助于消除这些影响的证据。
-
26
In other words, our planet took a beating that may have accelerated its own recovery.
换句话说，我们的星球遭受了殴打，可能加速了自身的复苏。
-
27
Thanks for listening, for Scientific American 60-Second Science. I'm Julia Rosen.
感谢您对科学美国人60秒科学的倾听。我是Julia Rosen.