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標 題: [情報]木星長出新的大紅斑
發信站: casamia (03/04/06 05:56:01 Sat)
NASA Science News for March 3, 2006
Backyard astronomers, grab your telescopes. Jupiter is growing a new red spot.
FULL STORY at
http://science.nasa.gov/headlines/y2006/02mar_redjr.htm?list766073
[以下簡單翻譯]
觀星族們快把望遠鏡拿出來吧--木星正長出了一個新的紅斑。
在菲律賓的Chistopher Go在二月二十七日用十一吋望遠鏡和CCD相機拍到
了這個新紅斑的影像。
[image] http://science.nasa.gov/headlines/y2006/images/redjr/go1.jpg
這個紅斑風暴的官方名稱是"橢圓BA (Oval BA)"，不過也許叫它"小紅 (Red Jr.)"
更貼切。跟木星最著名的大紅斑相比，小紅只有一半大小，但兩者顏色完全相同。
橢圓BA是2000年時，三個小風暴碰撞合併之後出現的。當時天文學家透過哈伯與
其他望遠鏡觀察到這個有趣的現象。其實幾個世紀以前，也是由風暴合併才產生
了約是地球兩倍大，壽命至少已三百多年的大紅斑。
橢圓BA剛成形時，跟先前合併的風暴一樣是白色的，但是在最近幾個月卻開始改
變。
Christopher Go說，"去年十一月的時候它還是白色的，到十二月慢慢變成棕色，
幾個星期前開始變紅，現在它的顏色跟大紅斑一模一樣!"
Glenn Orton是噴射推進實驗室(JPL)的天文學家，專門研究木星與其他巨大行星
上的風暴。他興奮地說，"我們這幾年一直在觀測木星，想看看橢圓BA究竟會不會
變紅--現在答案幾乎是肯定的了，這些現象非常有說服力。" (叫它"小紅"?
Orton說他比較想叫它"小大紅斑(the not-so Great Red Spot)")
為什麼是紅色的呢?
其實沒有人知道大紅斑之所以是紅色的確實原因。一個比較普遍的說法是，風暴
把深藏在木星雲層下方的物質帶到高空，受太陽紫外線照射後，發生某些未知的
化學反應，最後呈現了眾所皆知的磚紅色。
Orton說，"大紅斑是木星上，甚至是整個太陽系中最大的風暴，它的頂部比周圍
雲系高出八公里，就是要這麼強大的風暴才可把物質抬升到高處。"
而小紅現在的強度可能已足夠將物質推到雲層上方，就像大紅斑一樣，紫外線讓
一些會變色的化合物(chromophores)轉成紅色。如果這個推測是正確的，那麼紅
色加深可能代表著風暴正在增強。
"木星:巨大的行星 (Jupiter: The Giant Planet)"一書的作者 John Rogers表示，
木星有一些白斑之前也是略帶紅色，在1999年底就有觀察到一些案例，不過這樣的
現象並不多見，也不持久。John Rogers在書裡重新回顧了近百年來望遠鏡觀測木
星的資料，他認為，注意橢圓BA是否將一直維持紅色，會是個相當有趣的題目。
你也可以親眼看看--最近木星在黎明時很容易找到。日出前到戶外，朝南看再往上，
[星圖]http://science.nasa.gov/headlines/y2006/images/redjr/skymap_north.gif
木星比周圍的星都亮，用小望遠鏡就可以辨認出木星的雲帶和四顆最大的衛星；
如果用十吋口徑以上的望遠鏡再配合CCD相機，就能輕鬆追蹤小紅。
接下來會有什麼變化呢? 小紅會一直是紅色嗎? 它會成長還是消散? 請密切注意
後續發展。
[報導原文]
Backyard astronomers, grab your telescopes. Jupiter is growing a new red spot.
Christopher Go of the Philippines photographed it on February 27th using an
11-inch telescope and a CCD camera:
[image] http://science.nasa.gov/headlines/y2006/images/redjr/go1.jpg
The official name of this storm is "Oval BA," but "Red Jr." might be better.
It's about half the size of the famous Great Red Spot and almost exactly the
same color.
Oval BA first appeared in the year 2000 when three smaller spots collided and
merged. Using Hubble and other telescopes, astronomers watched with great
interest. A similar merger centuries ago may have created the original Great
Red Spot, a storm twice as wide as our planet and at least 300 years old.
At first, Oval BA remained white—the same color as the storms that combined
to create it. But in recent months, things began to change:
"The oval was white in November 2005, it slowly turned brown in December
2005, and red a few weeks ago," reports Go. "Now it is the same color as the
Great Red Spot!"
"Wow!" says Dr. Glenn Orton, an astronomer at JPL who specializes in studies
of storms on Jupiter and other giant planets. "This is convincing. We've been
monitoring Jupiter for years to see if Oval BA would turn red—and it finally
seems to be happening." (Red Jr? Orton prefers "the not-so-Great Red Spot.")
Why red?
Curiously, no one knows precisely why the Great Red Spot itself is red. A
favorite idea is that the storm dredges material from deep beneath Jupiter's
cloudtops and lifts it to high altitudes where solar ultraviolet
radiation--via some unknown chemical reaction—produces the familiar brick
color.
"The Great Red Spot is the most powerful storm on Jupiter, indeed, in the
whole solar system," says Orton. The top of the storm rises 8 km above
surrounding clouds. "It takes a powerful storm to lift material so high," he
adds.
Oval BA may have strengthened enough to do the same. Like the Great Red Spot,
Red Jr. may be lifting material above the clouds where solar ultraviolet rays
turn "chromophores" (color-changing compounds) red. If so, the deepening red
is a sign that the storm is intensifying.
"Some of Jupiter's white ovals have appeared slightly reddish before, for
example in late 1999, but not often and not for long," says Dr. John Rogers,
author of the book "Jupiter: The Giant Planet," which recounts telescopic
observations of Jupiter for the last 100+ years. "It will indeed be
interesting to see if Oval BA becomes permanently red."
See for yourself: Jupiter is easy to find in the dawn sky. Step outside
before sunrise, look south and up:
[sky map]http://science.nasa.gov/headlines/y2006/images/redjr/skymap_north.gif
Jupiter outshines everything around it. Small telescopes have no trouble
making out Jupiter's cloudbelts and its four largest moons. Telescopes
10-inches or larger with CCD cameras should be able to track Red Jr.
with ease.
What's next? Will Red Jr. remain red? Will it grow or subside? Stay tuned for
updates.
--
※ 發信站: 卡莎米亞(bbs.as.ntu.edu.tw)
◆ From: 131.215.220.112
標 題: [情報]木星長出新的大紅斑
發信站: casamia (03/04/06 05:56:01 Sat)
NASA Science News for March 3, 2006
Backyard astronomers, grab your telescopes. Jupiter is growing a new red spot.
FULL STORY at
http://science.nasa.gov/headlines/y2006/02mar_redjr.htm?list766073
[以下簡單翻譯]
觀星族們快把望遠鏡拿出來吧--木星正長出了一個新的紅斑。
在菲律賓的Chistopher Go在二月二十七日用十一吋望遠鏡和CCD相機拍到
了這個新紅斑的影像。
[image] http://science.nasa.gov/headlines/y2006/images/redjr/go1.jpg
這個紅斑風暴的官方名稱是"橢圓BA (Oval BA)"，不過也許叫它"小紅 (Red Jr.)"
更貼切。跟木星最著名的大紅斑相比，小紅只有一半大小，但兩者顏色完全相同。
橢圓BA是2000年時，三個小風暴碰撞合併之後出現的。當時天文學家透過哈伯與
其他望遠鏡觀察到這個有趣的現象。其實幾個世紀以前，也是由風暴合併才產生
了約是地球兩倍大，壽命至少已三百多年的大紅斑。
橢圓BA剛成形時，跟先前合併的風暴一樣是白色的，但是在最近幾個月卻開始改
變。
Christopher Go說，"去年十一月的時候它還是白色的，到十二月慢慢變成棕色，
幾個星期前開始變紅，現在它的顏色跟大紅斑一模一樣!"
Glenn Orton是噴射推進實驗室(JPL)的天文學家，專門研究木星與其他巨大行星
上的風暴。他興奮地說，"我們這幾年一直在觀測木星，想看看橢圓BA究竟會不會
變紅--現在答案幾乎是肯定的了，這些現象非常有說服力。" (叫它"小紅"?
Orton說他比較想叫它"小大紅斑(the not-so Great Red Spot)")
為什麼是紅色的呢?
其實沒有人知道大紅斑之所以是紅色的確實原因。一個比較普遍的說法是，風暴
把深藏在木星雲層下方的物質帶到高空，受太陽紫外線照射後，發生某些未知的
化學反應，最後呈現了眾所皆知的磚紅色。
Orton說，"大紅斑是木星上，甚至是整個太陽系中最大的風暴，它的頂部比周圍
雲系高出八公里，就是要這麼強大的風暴才可把物質抬升到高處。"
而小紅現在的強度可能已足夠將物質推到雲層上方，就像大紅斑一樣，紫外線讓
一些會變色的化合物(chromophores)轉成紅色。如果這個推測是正確的，那麼紅
色加深可能代表著風暴正在增強。
"木星:巨大的行星 (Jupiter: The Giant Planet)"一書的作者 John Rogers表示，
木星有一些白斑之前也是略帶紅色，在1999年底就有觀察到一些案例，不過這樣的
現象並不多見，也不持久。John Rogers在書裡重新回顧了近百年來望遠鏡觀測木
星的資料，他認為，注意橢圓BA是否將一直維持紅色，會是個相當有趣的題目。
你也可以親眼看看--最近木星在黎明時很容易找到。日出前到戶外，朝南看再往上，
[星圖]http://science.nasa.gov/headlines/y2006/images/redjr/skymap_north.gif
木星比周圍的星都亮，用小望遠鏡就可以辨認出木星的雲帶和四顆最大的衛星；
如果用十吋口徑以上的望遠鏡再配合CCD相機，就能輕鬆追蹤小紅。
接下來會有什麼變化呢? 小紅會一直是紅色嗎? 它會成長還是消散? 請密切注意
後續發展。
[報導原文]
Backyard astronomers, grab your telescopes. Jupiter is growing a new red spot.
Christopher Go of the Philippines photographed it on February 27th using an
11-inch telescope and a CCD camera:
[image] http://science.nasa.gov/headlines/y2006/images/redjr/go1.jpg
The official name of this storm is "Oval BA," but "Red Jr." might be better.
It's about half the size of the famous Great Red Spot and almost exactly the
same color.
Oval BA first appeared in the year 2000 when three smaller spots collided and
merged. Using Hubble and other telescopes, astronomers watched with great
interest. A similar merger centuries ago may have created the original Great
Red Spot, a storm twice as wide as our planet and at least 300 years old.
At first, Oval BA remained white—the same color as the storms that combined
to create it. But in recent months, things began to change:
"The oval was white in November 2005, it slowly turned brown in December
2005, and red a few weeks ago," reports Go. "Now it is the same color as the
Great Red Spot!"
"Wow!" says Dr. Glenn Orton, an astronomer at JPL who specializes in studies
of storms on Jupiter and other giant planets. "This is convincing. We've been
monitoring Jupiter for years to see if Oval BA would turn red—and it finally
seems to be happening." (Red Jr? Orton prefers "the not-so-Great Red Spot.")
Why red?
Curiously, no one knows precisely why the Great Red Spot itself is red. A
favorite idea is that the storm dredges material from deep beneath Jupiter's
cloudtops and lifts it to high altitudes where solar ultraviolet
radiation--via some unknown chemical reaction—produces the familiar brick
color.
"The Great Red Spot is the most powerful storm on Jupiter, indeed, in the
whole solar system," says Orton. The top of the storm rises 8 km above
surrounding clouds. "It takes a powerful storm to lift material so high," he
adds.
Oval BA may have strengthened enough to do the same. Like the Great Red Spot,
Red Jr. may be lifting material above the clouds where solar ultraviolet rays
turn "chromophores" (color-changing compounds) red. If so, the deepening red
is a sign that the storm is intensifying.
"Some of Jupiter's white ovals have appeared slightly reddish before, for
example in late 1999, but not often and not for long," says Dr. John Rogers,
author of the book "Jupiter: The Giant Planet," which recounts telescopic
observations of Jupiter for the last 100+ years. "It will indeed be
interesting to see if Oval BA becomes permanently red."
See for yourself: Jupiter is easy to find in the dawn sky. Step outside
before sunrise, look south and up:
[sky map]http://science.nasa.gov/headlines/y2006/images/redjr/skymap_north.gif
Jupiter outshines everything around it. Small telescopes have no trouble
making out Jupiter's cloudbelts and its four largest moons. Telescopes
10-inches or larger with CCD cameras should be able to track Red Jr.
with ease.
What's next? Will Red Jr. remain red? Will it grow or subside? Stay tuned for
updates.
--
※ 發信站: 卡莎米亞(bbs.as.ntu.edu.tw)
◆ From: 131.215.220.112
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