未設定
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This NASA Hubble Space Telescope image of Comet C/2012 S1 (ISON) was photographed on April 10, when the comet was slightly closer than Jupiter’s orbit at a distance of 386 million miles from the Sun (394 million miles from Earth).
Even at that great distance the comet is already active as sunlight warms the surface and causes frozen volatiles to sublimate. A detailed analysis of the dust coma surrounding the solid, icy nucleus reveals a strong jet blasting dust particles off the sunward-facing side of the comet’s nucleus.
Preliminary measurements from the Hubble images suggest that the nucleus of ISON is no larger than three or four miles across. This is remarkably small considering the high level of activity observed in the comet so far, said researchers. Astronomers are using these images to measure the activity level of this comet and constrain the size of the nucleus, in order to predict the comet’s activity when it skims 700,000 miles above the Sun’s roiling surface on November 28.
The comet’s dusty coma, or head of the comet, is approximately 3,100 miles across, or 1.2 times the width of Australia. A dust tail extends more than 57,000 miles, far beyond Hubble’s field of view.
More careful analysis is currently underway to improve these measurements and to predict the possible outcome of the sungrazing perihelion passage of this comet.
This image was taken in visible light with Hubble’s Wide Field Camera 3. The blue false color was added to bring out details in the comet’s structure.
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しずかなよい午後ですね。
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手打そば くりはらにて。
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ぴよじ。見上げちう。
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ごろん。
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ぴよじ。
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撫子の花。今日の大磯城山公園、城山庵での野外ライブで、たまたま茅ヶ崎からここに来て、自分のために花を買ったんだけれど、ライブを見て、花のイメージと合っていたから、と、もちろんお初のお客さま、若い女性とお母様、からいただきました。お二人とも、不思議なご縁を感じてらっしゃったご様子。わたしも、なにかはじめて会った気がしないのでした。こういうことは、とくにここ最近、とても多いような。ご自分のための撫子の花、何かわたしとリンクしたのですね。素敵。ありがたかったです。
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富士山と河口湖。
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八ヶ岳のパーキングエリアから。
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八ヶ岳のPAから見える山並み
