What is dust made of? - Michael Marder

1,075,389 views ・ 2018-05-24

TED-Ed


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翻译人员: Xinran Yu 校对人员: Carol Wang
00:06
Meet Dermatophagoides farinae.
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见识一下美洲尘螨,
00:09
Crawling around on eight legs,
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它用八只脚四处爬行,
00:11
this creature has no eyes to appreciate the kaleidoscope of colors around her.
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这种生物是没有眼睛的, 无法欣赏其周边环境的色彩斑斓。
00:16
She relies on her extraordinary sense of smell
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它依靠超凡的嗅觉,
00:19
to lead her to food and safe places to lay eggs.
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去找食物以及产卵的安全地方。
00:23
And she’s smaller than a pinhead.
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它比针头还小。
00:27
Dermatophagoides farinae is a dust mite.
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美洲尘螨是一种尘螨,
00:30
Less than a tenth the size of an ant,
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体型不到一只蚂蚁的十分之一,
00:32
a dust mite’s whole world is contained in the dusty film under a bed
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尘螨的生活的世界就在 一张床下或者一个被遗忘角落
00:37
or in a forgotten corner.
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的薄薄灰尘之中。
00:39
This realm is right under our noses, but from our perspective,
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尘螨的王国就在我们眼皮底下, 但在我们看来,
00:43
the tiny specks of brilliant color blend together into a nondescript grey.
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这些色彩艳丽的微粒 集中在一起却是单调的灰色。
00:49
What are these colorful microscopic particles?
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这些色彩斑斓的微小粒子是什么?
00:53
What distinguishes the dust in your house from, say, sand on a beach
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房间里的灰尘与海滩的沙 的区别在于,
00:57
is that it is a mixture of many different ingredients.
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灰尘中包含了许多不同物质。
01:01
It can contain grains of sand,
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它包含沙粒、
01:03
dead skin cells,
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死亡的皮肤细胞、
01:04
tiny hairs and threads,
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微小毛发和线头、
01:06
animal dander,
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动物毛屑、
01:07
pollen,
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花粉、
01:08
manmade pollutants,
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人造污染物、
01:09
minerals from outer space,
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来自外界的矿物质,
01:11
and, of course, dust mites.
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当然,还有尘螨。
01:14
Dust mites eat animal dander,
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尘螨会吃动物毛屑、
01:16
human skin,
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人类皮肤,
01:17
and some fungi.
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以及一些霉菌。
01:19
We shed dead skin cells constantly,
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我们经常会有 死亡的皮肤细胞脱落,
01:21
and wherever we live, they mix into the household dust.
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不论我们住在哪里,它们都会 和家中的灰尘混合在一起。
01:25
The same goes for our pets:
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我们的宠物也是这样:
01:27
their dander and hairs enter the mix,
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它们的皮屑和毛发都会混和进去,
01:30
as do tiny pieces of thread and cotton fibers from our clothes.
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我们衣物上的小线头 以及棉纤维也会混和进去。
01:34
These components make every household’s dust
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这些成分会让每户人家的灰尘
01:38
a unique blend of bits from its particular inhabitants.
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都成为了来自住户独特的混合灰尘。
01:42
Household dust also contains substances that blow in from the wider world.
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家中的灰尘也包含了 从外界吹进来的物质。
01:47
Depending on the local geology,
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根据当地的地质情况而异,
01:49
finely ground quartz, coal, or volcanic ash
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微细的石英粉、煤,或火山灰
01:53
might enter the air as atmospheric dust,
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都可能会以大气灰尘的形式 进入空气当中,
01:56
along with pollen and fungal spores.
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并伴随着花粉以及菌类孢子。
01:59
Industrial activities also contribute cement powder,
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工业活动也产生水泥粉末、
02:03
particles from car tires,
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来自汽车轮胎的微粒,
02:04
and other chemicals to the airborne mix.
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以及其他化学物质, 这些都会混合在空气中。
02:07
The combination of these elements can be as unique as a fingerprint.
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这些元素的组合就像 指纹一样独一无二。
02:11
In Spain, where the land is rich in carbonate materials,
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在西班牙,土地富含碳酸盐物质,
02:15
dust contains 20 times as much calcium as dust in Nigeria,
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那里灰尘中的钙含量 是地质情况截然不同
02:20
where the geology is quite different.
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的尼日利亚的二十倍。
02:22
After a particularly violent storm,
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在一场特别的强烈暴风之后,
02:24
scientists identified dust from the Sahara Desert
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科学家在伦敦依靠独特成分
02:27
thousands of miles away in London,
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辨识出了数千里之外
02:31
based on its specific composition.
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的撒哈拉沙漠尘土。
02:33
In the future,
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在未来,
02:34
we may be able to pinpoint the origins of dust samples even more specifically,
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我们有可能更明确地 定位出灰尘样本
02:39
down to a particular neighborhood or even house -
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是属于哪个社区, 甚至哪间房子——
02:43
something that may be of great help for forensic specialists.
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这可能会对法医很有帮助。
02:48
In addition to markers of humans, animals, and landscapes,
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灰尘所含的粒子, 除了来自人类、动物和环境之外,
02:52
dust also contains particles from further afield.
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还可能来自更远的地方。
02:56
When a star explodes in a distant galaxy,
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当一颗恒星在遥远的星系爆炸时,
02:59
super hot gases vaporize everything nearby.
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高温气体会蒸发附近的所有物质。
03:04
Then, the dust settles; minerals condense out of the gas.
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接着,尘土会沉积下来; 气体凝结成矿物质。
03:09
Floating out there between planets and galaxies,
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这些在行星和星系之间漂 浮的外星尘埃
03:12
this extraterrestrial dust contains tiny pieces of extinguished stars
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包含了已经消失的恒星的微小碎片,
03:18
and the building blocks of future celestial bodies.
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以及形成未来天体的基石。
03:22
Every year, tens of thousands of tons of cosmic dust
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每年,数万吨的宇宙尘土
03:26
lands on Earth and mingles with terrestrial minerals.
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降落在地球上, 与陆地矿物质混合在一起。
03:30
This blend of chemicals, minerals, and intergalactic particles
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这种化学物质,矿物, 以及银河间粒子的混合物
03:34
settles out of the air onto surfaces in our homes,
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会从空气中沉积下来, 落在房屋表面,
03:38
mixing with the detritus of each house’s occupants.
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与房屋中的居住者 产生的碎屑混合。
03:41
Stars explode,
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星星会爆炸,
03:43
mountains erode,
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山脉会被侵蚀,
03:44
and buildings, plants, and animals
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建筑物、植物,及动物
03:46
are all slowly but surely pulverized into fine grey powder.
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都会无可避免地 慢慢地变成灰色粉末。
03:52
We’re all destined to become dust,
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我们都注定要化为尘土,
03:54
but it’s also possible that we came from it.
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但我们也有可能 是来自于尘土。
03:57
Interstellar dust has been found to carry organic compounds through space.
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我们已经发现,星际尘土 会带着有机复合物穿过太空。
04:03
It’s possible that billions of years ago,
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有可能在数十亿年前,
04:06
some of these cosmic particles were the seed of life
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某些宇宙粒子正是我们在
04:09
on our little blue planet.
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这蓝色小星球上的生命种子。
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