§Week5火星探險

Potentially(淺在) life-giving water still flows across the ancient surface of Mars from time to time, NASA scientists said Monday (September 28) in revealing(揭示) a potential breakthrough(突破) in both the search for life beyond Earth and human hopes to one day travel there.

While the discovery doesn't by itself offer evidence of life on Mars, either past or present, it does boost hopes that the harsh landscape still offers some refuge for microbes微生物to cling依偎to existence.

"The existence of liquid water, even if it is super salty briny water, gives the possibility that if there's life on Mars, that we have a way to describe how it might survive," said John Grunsfeld, associate administrator管理員for the Science Mission Directorate at NASA.

NASA researchers using an imager aboard the Mars Reconnaissance Orbiter confirmed確認the watery含水flows by looking at light waves returned from seasonal dark streaks on the surface, long suspected to be associated with liquid water.

The investigation調查showed the streaks條紋absorb light at specific wavelengths 波長 associated with chemicals known to pull water from the Martian atmosphere in a process known as deliquescence潮解, said Georgia Tech doctoral博士student Lujendra Ojha, who first discovered the streaks while still an undergraduate本科student at the University of Arizona in 2011.

The chemicals allow the water to remain liquid at lower temperatures but also help keep it from boiling off in the thin atmosphere 大氣 of Mars, the researchers said.

Keyword:

microbes微生物

cling依偎

administrator管理員

watery含水

deliquescence潮解

undergraduate本科

confirmed確認

wavelengths波長

breakthrough突破

atmosphere 大氣

Structure of the lead

Who: NASA

When: 9/28
Where: Mars
What: NASA found liquid water in Mars

Why: NOT given

How: Not given

§Week4太空新發現

A range of majestic雄偉mountains meets with endless plains. On Pluto冥王星, billions of miles from the sun's reach, they are likely both made of ice.

And this week, we are seeing close-ups特寫of them with unprecedente空前的clarity. Finally, two months after the New Horizons spacecraft宇宙飛船flew by the dwarf矮人planet at close range, new higher resolution images have arrived.

It has taken that long for NASA to download them. The transfer speed of data from the spacecraft at 2,000 bits per second makes an old dial-up modem with its 56,000 bits per second look like a speed demon.

It will take NASA a year to transfer all the photos and data. The dump傾倒began arriving over the Labor Day weekend. Some of the pictures that NASA released were not single snapshots快照but compilations編譯synthesized合成 from multiple多種photos.

Judging by the first, crisp digital close-up images, the wait was worth it. They reveal a planet not frozen in place but with a complex landscape景觀still developing.

Pluto probe gets new assignment

Dunes? 沙丘

The photos taken from New Horizons' closest approach of Pluto on July 14 -- at about 50,000 million miles away -- reveal some surprises.

For example, there may even be dunes blown up by winds. But that would seem impossible on a planet with barely an atmosphere.

"Seeing dunes on Pluto -- if that is what they are -- would be completely wild, because Pluto's atmosphere today is so thin," said astronomer天文學家William B. McKinnon from Washington University in St. Louis.

"Either Pluto had a thicker atmosphere in the past, or some process we haven't figured out is at work. It's a head-scratcher."

And those gargantuan blocks of ice the size of mountains might be floating in flows of frozen nitrogen.

Key words

majestic雄偉

Pluto冥王星

close-ups特寫

unprecedented空前的

spacecraft宇宙飛船

dump傾倒

snapshots快照

dunes沙丘

synthesized合成

compilations編譯

Who: NASA

When : July 14

Where: Pluto

Why NO mention

What:NASA took a snapshots about Pluto

How: New Horizons spacecraft flew by the dwarf planet at close range