Europa moon 'spewing water jets' 木卫二表面“喷射出水汽”
Play audio file 科学家们已进一步证实，木星的卫星 —— 木卫二表面会向空中喷射水蒸气。在 2013 年，天文学家首次用哈勃望远镜观测到并发布了这一景象，而最近他们再一次目击了该现象。木卫二的星球表面下存在大量液态水，是除地球以外最有可能发现微生物的星球之一。请听 Jonathan Amos 的报道。
Europa is not much smaller than Earth's moon. But it couldn't look more different. Its surface is made from mottled ice, criss-cross like crazy paving. And it has one key feature that utterly fascinates scientists – it has a buried ocean of liquid water, far greater in volume than all the seas on Earth. And where there is water, there is a possibility of life, which makes the new Hubble observations so exciting.
The telescope has spied what appeared to be plumes of water vapour spewing hundreds of miles above the surface, presumably coming from this hidden ocean. One estimate is that the equivalent of an Olympic-sized swimming pool is being hurled upwards every ten minutes or so.
Before this is confirmed, it could transform our ability to find out whether micro-organisms do indeed exist on Europa because we would just need to fly through the plumes with a spacecraft and sample them. The alternative of having to land and drill down through a thick ice crust to reach the ocean and then search for life is a far more challenging prospect.
词汇表 Europa 木卫二，木星的卫星之一
mottled 斑驳的
criss-cross 纵横交错的
crazy paving 碎石路
volume 体积
observations 观测
spied 发现了
plumes 一缕缕（水汽、烟雾、灰尘等）
water vapour 水汽
spewing 喷出，涌出
estimate （对尺寸、价值、数量等的）估算
equivalent 等同于……的；和……等值的
micro-organisms 微生物（复数）
sample 给……取样
crust 外壳
prospect 设想
测验 请听报道并回答下列问题。
1. What makes the new Hubble observations so exciting?
2. True or False? Europa looks quite similar to Earth's moon.
3. How often is the equivalent of an Olympic swimming pool being hurled upwards?
4. Which word in the text means 'another possible choice or plan'?
答案 1. What makes the new Hubble observations so exciting?
The great volume of liquid water on Europa, which suggests a possibility of life, makes the new Hubble observations exciting.
2. True or False? Europa looks quite similar to Earth's moon.
False. Although Europa is not much smaller than Earth's moon, they look very different from each other.
3. How often is the equivalent of an Olympic swimming pool being hurled upwards?
Based on an estimate, it is being hurled upwards about every ten minutes.
4. Which word in the text means 'another possible choice or plan'?
Alternative.