英语听力：自然百科 探索世界奥秘之Life On Mars(火星生命)Unit12

But there was something even better. Odyssey¹ may not just have found ice. There may also be liquid water, and that means, there could be living creatures there too.

Right now, there might be liquid water on Mars. It's not gonna be on the surface. But if we go down deep enough, it's almost certain we'll find liquid water at some point beneath the ice.

It's all down to the interior of the planet. Scientists believe that Mars' heart may be a great core of molten rock and metal. At the very center, it could reach temperatures of almost 2,000 degrees centigrade. This heat is spread outwards², so that despite the very cold surface of Mars, just tens of meters down, it may be warm enough to melt ice.

What Odyssey is seeing really is maybe just the tip of the iceberg³, there could be, underneath⁴ that layer of ice that it could detect, a literal frozen ocean of water beneath that. Surprisingly, there could be life today on Mars beneath the ice in the liquid water, so the Odyssey results are also telling us that we ought to reconsider the possibility of life on Mars today, search for it more vigorously than we might have.

Odyssey's discoveries mean that there is now a genuine possibility that there is life on Mars. And if so, then we’ll soon have to start reconsidering our place in the universe. Odyssey's discoveries are so sensational⁵ that scientists are beginning to speculate: What strange creatures might be there waiting for us? What might an alien look like? Would they, for instance, be based on the same biological principles as we are?

When we look at life on Earth we see that all life on Earth uses the same chemistry, the same genetic⁶ code, the same hardware, the same software. It's really interesting to wonder if life on Mars, if it started independently, would it use the same code, the same chemicals?

On Earth, everything is based on DNA⁷, but could it be that life on Mars is completely different, that there is an utterly⁸ alien way of doing genetics.

genetic code: The sequence of nucleotides in DNA or RNA that determines the specific amino acid sequence in the synthesis of proteins. It is the biochemical basis of heredity and nearly universal in all organisms

1 odyssey   

n.长途冒险旅行；一连串的冒险

参考例句：

• The march to Travnik was the final stretch of a 16-hour odyssey.去特拉夫尼克的这段路是长达16小时艰险旅行的最后一程。
• His odyssey of passion, friendship,love,and revenge was now finished.他的热情、友谊、爱情和复仇的漫长历程，到此结束了。

2 outwards   

adj.外面的，公开的，向外的；adv.向外；n.外形

参考例句：

• Does this door open inwards or outwards?这门朝里开还是朝外开？
• In lapping up a fur,they always put the inner side outwards.卷毛皮时，他们总是让内层朝外。

3 iceberg   

n.冰山，流冰，冷冰冰的人

参考例句：

• The ship hit an iceberg and went under.船撞上一座冰山而沉没了。
• The glacier calved a large iceberg.冰河崩解而形成一个大冰山。

4 underneath   

adj.在...下面，在...底下；adv.在下面

参考例句：

• Working underneath the car is always a messy job.在汽车底下工作是件脏活。
• She wore a coat with a dress underneath.她穿着一件大衣，里面套着一条连衣裙。

5 sensational   

adj.使人感动的，非常好的，轰动的，耸人听闻的

参考例句：

• Papers of this kind are full of sensational news reports.这类报纸满是耸人听闻的新闻报道。
• Their performance was sensational.他们的演出妙极了。

6 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

7 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

8 utterly   

adv.完全地，绝对地

参考例句：

• Utterly devoted to the people,he gave his life in saving his patients.他忠于人民，把毕生精力用于挽救患者的生命。
• I was utterly ravished by the way she smiled.她的微笑使我完全陶醉了。