Business: English Skills
ビジネスチャンスを活かす英語力UPのために
残暑が続いていますが、皆さまお元気でお過ごしでしょうか？9月号のB項を担当させていただく小島です。
先月、火星に湖が存在する可能性があることが学術史「Science」で発表され、宇宙大好きの友人が嬉しそうに教えてくれました。今回はそんなちょっとワクワクする宇宙に関する記事を一部抜粋し、解説を行いたいと思います。
A Mars orbiter has detected a wide lake of liquid water hidden below the planet’s southern ice sheets. There have been much-debated hints of tiny, ephemeral amounts of water on Mars before. But it confirmed, this lake marks the first discovery of a long-lasting cache of the liquid. “This is potentially a really big deal,” says planetary scientist Briony Horgan of Purdue University in West Lafayette, Ind. “It’s another type of habitat in which life could be living on Mars today.” The lake is about 20 kilometers across, planetary scientist Robert Orosei of the National Institute of Astrophysics in Bologna, Italy and his colleagues report online July 25 in Science, but the water is buried beneath 1.5 kilometers of solid ice. (——)
The lake is probably not pure water－temperatures at the bottom of the ice sheet are around -68° Celsius, and pure water would freeze there, even under the pressure of so much ice (1). But a lot of salt dissolved in the water could lower the freezing point (2). Salts of sodium, magnesium, and calcium have been found elsewhere on Mars, and may be helping to keep this lake liquid (3). The pool could also more mud than water, but that could still be a habitable environment, Horgan says. Previously, scientists have discovered extensive solid water ice sheet under the Marian dirt. There were also hints that liquid water flowed down cliff walls, but those may turn out to be tiny dry avalanches. The Phoenix lander saw what looked like frozen water droplets at its site near the north pole in 2008, but that water may have been melted by the lander itself. “If this (lake) is confirmed, it’s a substantial change in our understanding of the present-day habitability of Mars,” says Lisa Pratt, NASA’s planetary protection officer. (——)
Under-ice lakes on Mars were first suggested in 1987, and the MARSIS team has been searching since Mars Express began orbiting the Red Planet in 2003. It took the team more than a decade to collect enough data to convince themselves the lake was real. (——) Finally discovering the lake is “a testament to perseverance and longevity,” says planetary scientist Isaac Smith of the Planetary Science Institute, who is based in Lakewood, Colo. “Long after everyone else gave up looking, this team kept looking.” (——)
———————————————————————————————————- By Lisa Grossman “Mars (probably) has a lake of liquid water- A lake beneath the Red Planet’s southern ice sheets may be the best place to find life” ScienceNews Planetary Science, Astrobiology, July 25th, 2018 https://www.sciencenews.org/article/mars-may-have-lake-liquid-water-search-life Reference August 2nd, 2018 ———————————————————————————————————-
●VOCABULARY●
orbiter 軌道衛星、ephemeral 束の間の、はかない、confirm 確かめる、確認する、承認する、Astrophysics 天体物理学、宇宙物理学、cache 隠し場所、extensive 広大な、広範囲に及ぶ、avalanche 雪崩、testament 証、証拠、perseverance 粘り強さ、忍耐（力）、longevity 年功
●解説●
(1)～(3)では、今回発見された湖がどのようなものか推測されていますので、見ていきましょう。
(1) The lake is probably not pure water－temperatures at the bottom of the ice sheet are around -68° Celsius, and pure water would freeze there, even under the pressure of so much ice. 湖の氷床下の水温は-68°にも及び、氷圧を考慮しても純水では凍ってしまう温度です。そのため、湖水は純水ではないと考えられます。何故凍らないのでしょうか？次の文章を見てみましょう。(2) But a lot of salt dissolved in the water could lower the freezing point. つまり、水中に溶解している多量の塩により、凍結温度が低くなっていると言うのです。この現象は私たちの生活の中でも利用されています。冬に道路が凍結しないように、塩化ナトリウムや塩化カルシウムを散布して水の凍結温度を下げるのもその一例です。(3)では火星において、ナトリウムやマグネシウム、カルシウムなどが発見されており、この湖を液体に保っている要因となっていることが示唆されています。氷結するはずの水がミネラルによって凍らないというのは面白いですね。
火星の地下に湖があり生物が存在するかもしれない、というのはなんだかワクワクしますね。学者たちが諦めずに研究を続けてきたのも素晴らしいと思いました。学術誌などを読む機会は少ないかと思いますが、SienceNewsなどを見ると比較的読みやすい量で身近な科学ニュースの記事と出会うことができます。普段見ないような英単語の勉強にもなりますので、ぜひ読んでみてください。
