If you observe sun spots over several years,  若连续观察太阳黑子好几年

they come and go with an about an eleven year cycle.  会发现它们约每隔11年会周期性地出现和消失

From solar minimum where there can be no spots at all  从连续数周或数月

on the sun for weeks or months at a time,  完全没有黑子的太阳活动极小期

to at maximum where you can have a hundred spots visible  到表面出现好几百个太阳黑子的太阳活动极大期

on the surface of the sun,and then they decline again,  接下来是为期约六年的衰退

usually over about six years or so,to, back to minimum.  直至进入太阳活动极小期为止

Until recently no-one knew what was driving the solar cycle.  我们到最近才得知太阳周期的原理

Or where sun spots came from.  及太阳黑子的由来

But people had always suspected that the scars on the suns surface  但人们早就怀疑太阳表面的瘢疤

had an effect on the Earth.  会影响地球

But no-one could quite put their finger on what it was.  只是说不出所以然来

It has been correlated with all kinds of different things,  人们认为太阳黑子与很多事情有关系

er the price of wheat,the thickness of fur on animals,  如谷物的价格，动物皮毛的厚度等

I'm inundated with it every day.  我每天都会收到大量讯息

I got a guy that comes to my website to try and predict the,  有个人上我的网站，为的就是用太阳黑子的位置

the stock market from the daily sunspot areas.  预测股市走向

You know, 'oh, you didn't post them today, I gotta know!'  他会说“你今天怎么没公布？我一定要知道”

So, are you making money or what,I want some if you are.  你究竟有没有赚到钱？有的话，我可是要分红的

One effect sun spots do have on the earth is on the climate.  我们可以确定的是，太阳黑子会影响地球气候

But it is a subtle effect.  但是影响并不明显

Its greatest impact was  其最大的冲击

only noticed 3 hundred years after the event.  在事发三百年后才被发现

It was discovered in Greenwich by the astronomer Robert Maunder  发现这件事的是天文学家罗伯蒙德

who was studying the hundreds of years of sunspot records  当时他在格林威治的皇家天文台

held at the Royal Observatory.  研究数百年来的太阳黑子纪录

And in the late part of the 19th century he er  他在十九世纪下半

became particularly interested in the sunspots.  开始对太阳黑子产生浓厚兴趣

He discovered that there had been this peculiar effect  他发现在十七和十八世纪下半

in the second half of the 17th and the 18th centuries  发生了奇怪的现象

when the sunspot numbers diminished to a real,  太阳黑子的数目减少

really a fraction of what they are today.  至今日的一小部分

And he described this as the Maunder minimum.  他将之称为“蒙德极小期”

For seventy years,from 1645-1715 sunspots disappeared.  从1645年到1715年，太阳黑子消失了70年

It was as if the engine that drives the solar cycle had stopped.  推动太阳周期的引擎仿佛熄火了

And it correlated almost exactly with the last period  北半球也在这段期间

of prolonged cold to strike the Northern hemisphere.  进入了漫长的寒冷期

They call it the Little Ice Age.  这就是“小冰河期”

What's interesting about a period like the little ice age is  小冰河期有意思的地方是

that you don't necessarily see a very large dip in temperatures,  温度并没有大幅降低

but nonetheless even a degree or two  不过尽管只降低了一、两度

is enough to see some really quite dramatic effects,  仍然产生了明显的结果

like pack ice advancing south from the north pole,  如北极的浮冰向南方延伸

like the Viking colonies in Greenland being wiped out  格陵兰的维京人聚落消失

by the changing climate and the population  随着变化的气候

of Iceland falling by half.  冰岛人口锐减五成

Now in Britain the weather was cold enough  英国也很冷

that the Thames would regularly freeze in winter  以至于泰晤士河在冬天会结冰

and one of the classic depictions of life  当时生活的最好写照

at the time is Frost Fairs,  就是冰霜市集

when the population would hold a fair on the frozen river.  人们会在冰冻河面上举行市集

So things really must have been a lot harsher  可见当时的气候绝对比现在

than they are today.  严酷得多