在线英语听力室_免费在线英语听力学习网站

地球绕太阳运行轨道如何影响冰河时代

Study Shows How Eartha??s Orbit Affects Ice Ages

An ice age is a period of reduced temperatures causing ice to cover large areas of the northern and southern parts of the world.

冰河时代是指气温下降，导致世界北部和南部大片地区被冰覆盖的时期。

A group of scientists studied changes in the shape of the Earth's orbit around the sun, the tilt of the Earth's axis and the movement of the axis itself, called a wobble.

一队科学家研究了地球绕太阳运行轨道形状、地轴倾斜度和被称为地轴摆动的地轴本身运动的变化。

These three motions are believed to happen in cycles.

人们认为这三种运动是周期性运动。

The Serbian scientist Milutin Milankovitch developed a theory about 100 years ago that these cycles affected Earth's long-term climate.

塞尔维亚科学家米卢廷·米兰科维奇在大约100年前提出了一个理论，认为这些周期性运动影响了地球的长期气候。

The team noted that small changes in Earth's orbit around the Sun caused predictable cycles of warming and cooling over a period of about 100,000 years.

该团队指出，地球绕太阳轨道的微小变化导致了可预测的升温和降温周期，周期大约为10万年。

These findings permitted the team to determine

这些发现使该团队能够确定

how the three factors of tilt, wobble, and the shape of Earth's orbit might have affected the Earth's climate over the last 900,000 years.

轴倾角、摆动和地球轨道形状这三个因素在过去90万年中如何影响地球的气候。

The group published its findings in Science on February 27.

该团队于2月27日在《科学》杂志上发表了其研究结果。

The scientists examined a million-year record of climate by looking at ice sheets across the northern half of the world and deep ocean temperatures.

科学家们通过观察世界北半部的冰盖和深海温度调查出一百万年来的气候记录。

They then compared this data with small but regular changes in Earth's orbit over time.

然后，他们将这些数据与地球轨道随时间而发生的微小但有规律变化进行了比较。

The lead writer of the study is Stephen Barker, a professor at Cardiff University in Britain.

这项研究的主要作者是英国卡迪夫大学的教授斯蒂芬·巴克。

He told the French News Agency (AFP) that

他告诉法新社（AFP），

for many years it has been difficult for scientists to show exactly how small changes in Earth's orbit have led to huge changes between warm and cold periods.

多年来，科学家一直很难准确说明地球轨道的微小变化如何导致暖期和冰期之间的巨大变化。

Earth is believed to go through cycles of ice ages and warm periods.

地球被认为经历了冰河期和暖期的循环。

The last ice age is thought to have ended around 11,700 years ago.

上一次冰河时代被认为结束于11700年前。

Scientists, such as Milankovitch, have long seen a connection between Earth's orbit and climate.

米兰科维奇等科学家很早就发现了地球轨道与气候之间的联系。

However, researchers have struggled to precisely date when each of the climate changes happened.

然而，研究人员一直难以准确确定每次气候变化发生的时间。

It has also been difficult for them to know exactly which orbit positions affect the start and stop of cold or warm periods.

他们也很难确切知道哪些轨道位置会影响冰期或暖期的开始与结束。

Barker said his team of researchers studied slow changes in temperature over long periods of time

巴克说他的研究团队研究了温度在很长一段时间内的缓慢变化，

instead of only looking at shorter periods of change between cold and warm climates.

而不是只观察寒冷气候和温暖气候之间较短时间内的变化。

Barker told AFP, "We would expect a glaciation to occur within the next 11,000 years, and it would end in 66,000 years' time."

巴克告诉法新社：“我们预计下一个冰期将在接下来的1.1万年内发生，并将在6.6万年后结束。”

Lorraine Lisiecki is a professor at the University of California, Santa Barbara, and a co-writer of the study.

洛林·利西茨基是加州大学圣巴巴拉分校的教授，也是该研究的合著者。

She said the study shows that changes in climate over tens of thousands of years are not random.

她说这项研究表明，数万年来气候的变化不是随机的。

The team aims to expand its findings to investigate the long-term effects of human activity on climate.

该团队的目标是扩大其研究结果，以调查人类活动对气候的长期影响。

They also want to find out how it might affect Earth's natural climate cycles.

他们还想弄清楚它如何影响地球的自然气候周期。

I'm Andrew Smith.

安德鲁·史密斯为您播报。