H☆Mさんの おぼえた日記 - 2018年4月1日(日)

[Oldest Trace of Life] -Lesson 44 / English in Today's World-

Japanese researchers say they've discovered the oldest trace of life on Earth. They claim it dates back nearly 4 billion years.

The scientists analyzed a substance called graphite in ancient rocks from northeastern Canada. They found a relatively high amount of a certain type of carbon - a sign of life.

Each grain of the graphite is no more than several dozen micrometers in length. "We believe they are a primitive life form, without a nucleus in the cell," a University of Tokyo researcher who led the study said of the grains. The microscopic organisms likely lived in the sea.

Earth is believed to be 4.5 billion years old. Very little is known about its early life forms. "Data from the first 500 million years are missing," the researcher said. "Our goal is to find out what happened in that period."

His team's findings were recently published in the international scientific journal Nature. They are now conducting further analysis to try to learn more about the organisms. (2017/9/28, NHK World)


[Discussion]
Sum: That's amazing! It's hard to imagine what life forms on Earth could have been like 4 billion years ago. Maybe the study of these trace amounts of carbon will give us a clue.

Hannah: You know, when you think about it, humans have only been on Earth for a relatively short time. I can't really grasp the idea of how long 4 billion years is!

Sum: Me neither. If the researchers' claim is correct, this is the oldest record of life on Earth. It's humbling to think just how many living things have come before us.

Hannah: Yes, it's an amazing chain of life 4 billion years long. What a precious history!

Sum: Indeed!


◆見出し[Oldest Trace of Life]
=The oldest trace of life (on Earth has been discovered.)
　⇒(Japanese researchers say they've discovered the) oldest trace of life (on Earth).

◆[life form]「生命体」=未知の生物、未知の生命体、宇宙人/宇宙の生命体
　⇒[We believe they are a primitive life form, without a nucleus in the cell.]
　私たちが考えるには、それらは原始的な生命体で、細胞内に核がありません。

◆[nearly]「～近く、ほとんど～、ほぼ～」…(ある数値を超えない範囲で～に近接した状態、その数値を超える場合は使わない)⇒[48,49]=[nearly 50]、[51,52]≠[nearly50]
　⇒[They claim it dates back nearly 4 billion years.]
　彼らは主張しています、それは40億年近く前のものだと。

◆[(relatively) high amount of-]「(比較的)多い量の…」
　⇒[Butter contains a high amount of fat.]
　バターには脂肪分が多い(割合/構成比率が高い)
　⇒[They found a relatively high amount of a certain type of carbon - a sign of life.]　彼らは見つけました、比較的多い量の特定の種類の炭素を―(それは)生命のしるしです。

◆[several]「(2を超える/数えられるものに対して/あいまいに/非常に感覚的に)多くはない数」
　⇒[no more than several dozen micrometers]「数十マイクロメートルに満たない」

■[trace]「(何かが残した)跡、痕跡」
Japanese researchers say they've discovered the oldest trace of life on Earth.
　⇒There wasn't a trace of anger in her voice.

■[claim]「主張する」
They claim it dates back nearly 4 billion years.
　⇒He claims that his mother makes the best "kenchin-jiru" in Japan.

■[relatively]「比較的」
They found a relatively high amount of a certain type of carbon - a sign of life.
　⇒He's relatively tall for his age, but isn't interested in playing basketball or volleyball.


[words and phrases]
-[graphite]グラファイト(炭素の塊/鉛筆の芯など)
-[grain]粒子
-[no more than several dozen micrometers in length]数十マイクロメートルに満たない長さ
-[primitive life form]原始的な生命体
-[nucleus](細胞などの)核/中心部、
-[microscopic]=[microscope]顕微鏡でないと見えない(ほど小さい)/微小の
-[organism]有機体/生命体/(微)生物
-[journal]専門的な定期刊行物/学術雑誌