New Evidence Suggests Large Water Ice Supply near Mars’ Equator

2024-02-05 14:15:00来源：网络

新的证据表明火星赤道附近存在大量水冰储备

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　　By Bryan Lynn

　　28 January 2024

　　A Mars explorer has discovered new evidence of a large amount of water ice buried near the planet's equator.

　　The discovery was made with data collected by the Mars Express orbiter. The spacecraft is operated by the European Space Agency (ESA). The American space agency NASA is a partner on the orbiter's mission.

　　ESA launched Mars Express in 2003 and it has been studying the Red Planet ever since. The mission's main goal is to use its seven scientific instruments to search for signs of water underneath the surface of Mars.

　　Scientists involved in the new research say data suggesting the presence of newly discovered ice deposits could mean Mars may have once supported life.

　　The Mars Express orbiter collected data around an area of the planet known as the Medusae Fossae Formation (or MFF). NASA describes this formation as "a soft, easily eroded deposit that extends for nearly 1,000 kilometers along the equator of Mars."

　　Scientists believe the MFF was most likely formed by wind-blown dust or volcanic ash. The formations could have formed after volcanic activity estimated to have taken place up to 3.8 billion years ago.

　　Images of the area show raised areas that scientists thought in the past might contain dust blown around the planet by wind over many years. But the new research used newer data collected by the orbiter's MARSIS instrument. It is "a subsurface radar sounder" with a 40-meter-long antenna. The tool looks for water on the surface, as well as up to five kilometers below the surface.

　　The MARSIS instrument is designed to send radio waves to an area scientists choose. It then attempts to listen to and examine "echoes" produced by the radio waves. The echoes help researchers recognize where water or ice might be, NASA explains.

　　Scientists say any water identified near the surface results in stronger signals while the presence of ice or other materials would produce weaker signals. The team said MARSIS readings suggest the MFF area of Mars contains a large amount of water ice rather than wind-blown dust.

　　Thomas Watters of the U.S. Smithsonian Institution led the new research. His team's findings were recently published in a study in Geophysical Research Letters. He said in a statement the radar data showed the deposits in the MFF area were even thicker than earlier measurement estimates had shown.

　　The researchers said the data showed the examined deposits extended beneath the Mars surface to depths up to 3.7 kilometers. They seemed to contain "layers of dust and ice, all topped by a protective layer of dry dust or ash."

　　Earlier data examinations of the MFF area found similarities in the electrical properties of deposits there to ice-rich deposits found in the planet's north and south poles. The latest MARSIS data strengthens this evidence by suggesting similarities between deposit layering in the MFF and the planet's poles.

　　"The radar signals match what we'd expect to see from layered ice," Watters said. He added that the radar waves were found to be "similar to signals we see from Mars's polar caps, which we know to be very ice rich."

　　It is not the first time scientists have discovered strong evidence for the presence of water ice on Mars. But the researchers say the latest study suggests the largest amount of water ever identified in the MFF area. They estimated the total amount of water contained there would be enough "to cover the surface of Mars to a depth of about 1.5 to 3 meters."

　　Colin Wilson is a project scientist with the Mars Express mission. He said while the new finding is exciting, it also "raises as many questions as answers." He continued, "How long ago did these ice deposits form, and what was Mars like at that time?" Wilson said if confirmed to be water ice, the large deposits "would change our understanding of Mars climate history."

　　Watters added that since the discovery was made in an area near the Martian equator, it could be considered a good place for future exploration missions. He explained that with a lower elevation, the MFF area would be considered "an ideal landing spot for spacecraft." Such an elevation provides more atmosphere to support an effective, controlled landing, Watters said.

　　I'm Bryan Lynn.

　　Bryan Lynn wrote this story for VOA Learning English, based on reports from the European Space Agency, NASA, Geophysical Research Letters and the Smithsonian.

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　　作者：Bryan Lynn

　　2024年1月28日

　　一台火星探测器发现了新的证据，证明火星赤道附近埋藏着大量的水冰。

　　这一发现是通过火星快车号轨道飞行器收集的数据得出的。这个飞行器由欧洲空间局（ESA）操作，美国航天局（NASA）是该轨道飞行器任务的合作伙伴。

　　欧洲空间局在2003年发射了火星快车号，自那时起一直在研究红色星球。该任务的主要目标是使用其七个科学仪器寻找火星地表下水的迹象。

　　参与新研究的科学家表示，数据暗示新发现的冰层的存在可能意味着火星曾经可能支持生命存在。

　　火星快车号轨道飞行器在火星的一个被称为美杜莎岩层（或MFF）的区域收集了数据。NASA将这个岩层描述为"一种软质、易于侵蚀的沉积物，沿着火星的赤道延伸近1000公里。"

　　科学家们认为，MFF很可能是由风吹来的尘土或火山灰形成的。这些地貌可能是在大约38亿年前的火山活动后形成的。

　　该地区的图像显示出科学家们过去认为可能包含多年来被风吹散的尘土的隆起地区。但新的研究使用了轨道飞行器的MARSIS仪器收集的新数据。它是一种"地下雷达探测器"，带有一个40米长的天线。该工具寻找地表上的水，以及地表下五公里的水。

　　MARSIS仪器的设计目的是向科学家选择的区域发送无线电波。然后，它试图听取并检查无线电波产生的"回声"。NASA解释说，这些回声帮助研究人员识别水或冰可能存在的地方。

　　科学家们说，任何在地表附近发现的水都会产生更强的信号，而冰或其他物质的存在会产生较弱的信号。该团队表示，MARSIS的读数表明，火星的MFF区域包含大量的水冰，而不是风吹来的尘土。