時(shí)差N小時(shí):火星上的海洋

Don: Hey, Yaël, Have you heard? We've discovered two new oceans?

嘿，Yaël，你聽(tīng)說(shuō)了嗎?我們已經(jīng)發(fā)現(xiàn)了兩塊新大洋。

Yaël: Where?

在哪啊?

D: On Mars. Well, they aren't there any longer, but they were there a few billion years ago.

在火星上。雖然現(xiàn)在不在那兒了，但幾十億年前一直都在。

Y: I thought scientists weren't sure if Mars had oceans or not.

我想科學(xué)家們還是不確定火星上到底有沒(méi)有海洋。

D: They weren't. The Mars Opportunity Rover found sulfates and other salts in the soil thatwere left behind when standing water evaporated. It also discovered cross-bedding in the soilwhich was created by water ripples, and tiny mineral deposits called blueberries that onlyappear if water is present. The northern lowlands of Mars looked like there might have been anocean there, but there wasn't definite proof.

恩，不確定。機(jī)遇號(hào)火星探測(cè)器在土壤中發(fā)現(xiàn)了水分長(zhǎng)期揮發(fā)后所留下的硫酸鹽和其它的鹽類(lèi)。同時(shí)還在土壤中發(fā)現(xiàn)了水波所形成的交錯(cuò)層，以及稱(chēng)之為藍(lán)莓的小型礦床，而這種礦床只有在存在水的地方才產(chǎn)生?；鹦堑谋辈康偷乜雌饋?lái)像是曾經(jīng)有過(guò)一片海洋，但還沒(méi)有發(fā)現(xiàn)確鑿的證據(jù)。

Y: So, what has changed their minds?

那又是什么讓科學(xué)家們改變了想法呢?

D: Gamma Ray evidence.

是伽馬射線(xiàn)。

Y: That sounds exciting.

聽(tīng)起來(lái)真令人興奮啊。

D: It is. The Mars Odyssey spacecraft had a gamma-ray spectrometer onboard that coulddetect elements buried as much as a third of a meter, or thirteen inches, below the soil.Scientists used the spectrometer to measure the amount of potassium, thorium, and ironabove and below what they thought to be the shoreline of ancient oceans. They expected to seelow concentrations above the shoreline and larger concentrations below. That would indicatethat the elements had been leached out of the soil by the water.

是啊。奧德賽號(hào)火星探測(cè)器有一個(gè)γ射線(xiàn)能譜儀主板，它可以檢測(cè)到埋藏于地底三分之一或地下13英寸的元素?？茖W(xué)家們利用光譜儀在所推斷的遠(yuǎn)古海洋海岸線(xiàn)附近測(cè)量鉀、釷、鐵的含量?？茖W(xué)家們預(yù)測(cè)海岸線(xiàn)上的元素濃度較低，而海岸線(xiàn)以下的濃度較高。這將證明那些元素是通過(guò)水過(guò)濾到土壤中的。

Y: So, what did they find?

那么他們究竟發(fā)現(xiàn)了什么呢?

D: They found the shorelines of a younger ocean about ten times the size of the MediterraneanSea, and an older ocean twice that size.

他們發(fā)現(xiàn)了一個(gè)較新，海岸線(xiàn)大約是地中海的10倍的海洋痕跡，和一個(gè)年代比較久遠(yuǎn)相當(dāng)于地中海海岸線(xiàn)兩倍的海洋痕跡。

Y: It's too bad those oceans still aren't there.

這些海洋已經(jīng)不在那兒真是太糟糕了。

D: Yeah. It sure would be a great spot for a cruise.

對(duì)啊，如果它們還在那兒，那將是個(gè)很適合巡航的地兒。