墨尔本PTE素材库——Great Red Spot Helps Explain Jupiter’s Warm Upper Atmosphere

墨尔本PTE素材库——Great Red Spot Helps Explain Jupiter’s Warm Upper Atmosphere

中文批注

遥远的木星一直是一个神秘的存在，很多人都熟知它的标志：大红斑。而天文学家们更关心的问题则是木星上层大气的温度问题：为什么木星比地球离太阳远5倍，但高层大气的温度竟然和地球差不多？让它高层大气保持这个温度的热量是从哪里来的？这段podcast就围绕这个问题展开了讨论，原来关键还是在于木星的标志——大红斑。

那么，听完了整段音频，你们能不能回答上述问题呢？

• 为什么木星的大气温度与地球相差不多？
• 木星是如何保持这个温度的？

澳大利亚语言学院整理的PTE素材库，旨在用最贴近PTE Official Question Criteria的材料，给大家提供一系列不同话题的PTE素材！让大家可以在平时练习听力、阅读、口语、写作，不至于陷入“题荒”的境地哦！这段材料可以用于练习Dictation和Re-tell Lecture，如果直接阅读Full Transcript的话也是一篇很好的阅读练习材料哦！

【Key Vocabulary】

recognizable adj. 可辨认的，可认识的

mysterious adj. 神秘的

planetary adj. 行星的

chilly adj. 寒冷的

orbit n. 轨道

originate v. 发源，发生

turbulent adj. 骚乱的，混乱的

auroral adj. 极光的，曙光的，玫瑰红的

theorist n. 理论家

equator n. 赤道

thermal adj. 热的，热量的

fluctuation n. 起伏，波动

Full Transcript

A thermal spike linked to the solar system’s largest storm explains weather on gas-giant planets.

For most people, Jupiter’s most recognizable—and mysterious—feature is the Great Red Spot. For centuries, astronomers have watched the storm spin across the giant world’s face.

But for planetary scientists, Jupiter’s most distinctive mystery may be what’s called the “energy crisis” of its upper atmosphere: how do temperatures average about as warm as Earth’s even though the enormous planet is more than fives times further away from the sun?

All the sun’s giant planets display this energy crisis, and those in chilly orbits around other stars probably have it, too. So where does the energy to heat their upper atmospheres come from?

According to a new study, the energy must originate within the giants, get transported upward and become amplified by turbulent storms. The finding appears in the journal Nature. [James O’Donoghue et al.,Heating of Jupiter’s upper atmosphere above the Great Red Spot]

This offers a new window into Jupiter’s depths, and should allow researchers to better understand gas-giant atmospheres throughout the universe. And it’s all connected to the Great Red Spot.

Astronomers have long known that auroral displays can heat Jupiter’s poles, where charged particles trapped in the planet’s intense magnetic field slam into its upper atmosphere. Some theorists thought this auroral heating could flow toward the equator to warm the planet’s mid-latitudes. So, using NASA’s Infrared Telescope Facility, astronomers observed Jupiter for nine hours, looking for these flows as thermal fluctuations in the planet’s upper atmosphere.

But they saw none.

Instead, in Jupiter’s mid-latitudes they spied a thermal spike 800 kilometers above the Great Red Spot, where temperatures soared hundreds of degrees higher than the surroundings. The best way to explain this spike is from the swirling maelstrom below, where turbulent atmospheric waves must generate heat by crashing together like breakers on a windy beach shore. Though this must be a planet-wide phenomenon, it is most obvious directly over Jupiter’s largest, most powerful storm.

As alien as it seems, scientists have seen the same behavior on much smaller, gentler scales here on Earth, when thunderheads rising over mountain ranges create rippling waves that heat the air above.

—Lee Billings

(Source: http://www.scientificamerican.com/podcast/episode/great-red-spot-helps-explain-jupiter-s-warm-upper-atmosphere/)