Magnetic Field Reversal
Scientists now believe that the Earth's magnetic field is about to reverse.
科學家們現(xiàn)在相信，地球的磁場即將反轉。
This is called magnetic field reversal.
這叫做磁場反轉。
Every 200,000 to 300,000 years, the Earth's magnetic field reverses.
每20萬到30萬年，地球的磁場就會發(fā)生逆轉。
In other words, the North and South magnetic poles switch places.
換句話說，北極和南極磁極互換位置。
This has happened many times in Earth's history, but it has been happening more lately.
這在地球歷史上已經(jīng)發(fā)生過很多次了，但是最近發(fā)生的更多。
What happens during a magnetic field reversal? -The Earth's magnetic poles switch places.
在磁場翻轉過程中會發(fā)生什么?-地球的磁極互換位置。
What happens to magnetic field reversal??-The Earth's magnetic poles switch places.
磁場反轉會發(fā)生什么?-地球磁極的位置變換。
Scientists now?believe that?the Earth's magnetic field is?about to reverse.
科學家們現(xiàn)在相信，地球的磁場即將反轉。
Recent research provides evidence that there have been five magnetic reversals during the past 500,000 years.
最近的研究提供了證據(jù)，表明在過去的50萬年中，地球經(jīng)歷了5次磁極倒轉。
The most recent event happened approximately 41,000 years ago.
最近一次發(fā)生在大約41000年前。
Recent studies have found that the Earth's magnetic field has weakened about 5% per decade.
最近的研究發(fā)現(xiàn)，地球磁場每十年減弱約5%。
At its current rate, the next reversal could happen within the next century.
按照目前的速度，下一個逆轉可能在下個世紀發(fā)生。
How long is a decade???-10 years
十年有多長?-10年
According to the recent research, how long ago does the last reversal occur? -about?41,000 years ago
根據(jù)最近的研究，最近一次逆轉發(fā)生在多久以前?-大約41000年前
Many scientists?believe?that the Earth's magnetic field is?due?to the Earth's?rotation.
許多科學家認為地球的磁場是由地球的自轉引起的。
Some people worry about the effects of a magnetic field reversal.
有些人擔心磁場反轉的影響。
They think there is a possibility that it could cause many problems.
他們認為這可能會引起很多問題。
For example, without a magnetic field, communications could be disrupted.
例如，如果沒有磁場，通信就會中斷。
Birds and other forms of life could become confused and get lost.
鳥類和其他形式的生命可能會迷失方向。
Another effect would be an increase in some forms of cancer, especially skin cancer.
另一個影響是某些癌癥的增加，尤其是皮膚癌。
This would be because of an increase in the amount of radiation absorbed by our bodies.
這可能是因為我們身體吸收的輻射量增加了。
The possibility that a field reversal would be an extinction event is very low.
場反轉成為滅絕事件的可能性非常低。
There is very little historical evidence to show that previous reversals have caused extinctions.
很少有歷史證據(jù)表明以前的逆轉導致了物種滅絕。
Humans have been on Earth for millions of years, during which there have been many reversals.
人類已經(jīng)在地球上生活了數(shù)百萬年，其間有過多次逆轉。
Therefore, scientists believe that any changes would be temporary.
因此，科學家認為任何變化都是暫時的。
Another theory is that the Earth's outer layer could rotate around the liquid metal outer core that makes up most of the earth.
另一種理論是，地球的外層可以繞著構成地球大部分的液態(tài)金屬外核旋轉。
So in the next reversal continents could shift positions, from north to south.
所以在下一次的倒轉中，大陸可能會改變位置，從北到南
Imagine, if that happened, Australia would be in the northern hemisphere.
想象一下，如果那樣的話，澳大利亞會在北半球。
How likely is it?that a field reversal would be an extinction event?- It's highly unlikely.
場反轉是滅絕事件的可能性有多大?-不太可能。
The possibility?that?a field reversal?would?be an extinction?event?is very?low. There is very little historical?evidence?to show that?previous?reversals have?caused?extinctions.
場反轉成為滅絕事件的可能性非常低。很少有歷史證據(jù)表明以前的逆轉導致了物種滅絕。
With so many theories, how can we know what to believe?
有這么多的理論，我們怎么知道該相信什么呢?
This is important because some events require us to act well in advance.
這一點很重要，因為有些事件需要我們提前采取行動。
Otherwise it will be too late to prevent a catastrophe.
否則，要阻止一場災難就太遲了。
This underlines the importance of getting reliable information, backed by strong? evidence.
這強調了獲得可靠信息的重要性，并有強有力的證據(jù)支持。
