BBC随身英语:Crowded universe? 在其它星球上的生命

Sean McMahon, who is carrying out the work, explained: "Traditionally people have said that if a planet is in this Goldilocks zone - not too hot and not too cold - then it can have liquid water on its surface and be habitable."

But this perception might change when considering that planets can receive two sources of heat - heat direct from the star and heat generated deep inside the planet.

It is easy to observe it in our own planet. As you descend through the crust of the Earth, the temperature gets higher and higher. Even when the surface is frozen, water can exist below ground.

There could be immense quantities of water in fact - teeming with primitive life.

Professor John Parnell, also from Aberdeen University said: "There is a significant habitat for microorganisms below the surface of the Earth, extending down several kilometres".

"And some believe that the bulk of life on Earth could even reside in this deep biosphere."

So the Aberdeen team are developing models to predict which far-flung planets might harbour underground reservoirs of liquid water with the possibility of alien life.

Quiz 测验 What sign suggests to scientists that a planet can sustain life?

The existence of water.

Where might the heat in a planet come from?

The heat can come directly from its star or be generated deep inside the planet.

Is the following statement true, false or not given? Even at high temperatures there is plenty of life deep below the surface of the Earth.

True.

What phrasal verb in the article means to put something in a place from where it cannot be removed easily?

To lock away

What word is used to refer to beings that are very small?

Microorganisms

Glossary 词汇表 computer model计算机模型 habitable可居住的 to sustain维持 likelihood可能性 surface地表 underground地下 fundamental基本的 atmosphere大气层 evaporation蒸发，挥发 on the other hand另一方面 locked away锁了起来 Goldilocks zone宜居带，可居住地区 to descend向下 crust of the Earth地球的地壳 to teem充满 habitat生存环境 microorganism微生物 biosphere生物圈 far-flung遥远的 to harbour隐藏 reservoir水库