radiation belt
ナサの宇宙探索機が，木星の軌道に乗りました。5年の歳月を掛けて木星に到着したようです。近くで木星を観察することで，木星が誕生した原因を明らかにすることが期待されております。
記事の中で気になった表現は"radiation belt"です。Oxford Dictionaries.comで調べると，天文学の用語で"A region surrounding a planet where charged particles accumulate under the influence of the planet’s magnetic field"という定義がありました。「惑星の磁場に影響されて，荷電粒子が蓄積する地帯」のことを指すようです。木星付近に宇宙探索機を飛ばすと，特別なプロテクターを施さないかぎり，強力な磁場によって破壊されてしまうそうです。(Ume)
Juno probe enters into orbit around Jupiter
Engineers had warned in advance that the engine firing was fraught with danger.
No previous spacecraft has dared pass so close to Jupiter; its intense radiation belts can destroy unprotected electronics.
One calculation even suggested the orbit insertion would have subjected Juno to a dose equivalent to a million dental X-rays.
But the probe is built like a tank with titanium shielding, and the 35-minute rocket burn appeared to go off without a hitch.
"Nasa did it again," said an elated Scott Bolton, Juno's principal investigator. "That says it all to me. And I'm so happy to be part of the team that did that. I mean this team has worked so hard and we have such great people. And it's almost like a dream coming true right here."
