知识酷图系列—酷图4——HST拍的“赛德娜”

http://www.newsmth.com/bbscon.php?bid=207&id=47955

发信人: yanxiaoxing (dpim), 信区: Astronomy
标  题: 哈勃的照片下到了
发信站: BBS 水木清华站 (Thu Apr 15 17:44:28 2004)

Sedna Mystery Deepens as Hubble Offers Best Look at Farthest Planetoid





This is the clearest-ever view of the farthest object yet discovered in the solar system. The object is unofficially named "Sedna" (after an Inuit goddess of the sea).

[Lower right]

At a distance of over 8 billion miles, Sedna is so far away it is reduced to one picture element (pixel) in this image, taken in high-resolution mode with Hubble's Advanced Camera for Surveys. This image sets an upper limit on Sedna's size of 1,000 miles in diameter. It is surprising that Hubble does not see a suspected moon near the planetoid. Either the moon's not there, or, far less likely, it is being eclipsed by Sedna, or it is transiting Sedna. The gravitational tug of a moon would best explain Sedna's extremely slow rotation of between 20-50 days, as inferred from ground-based photometric observations.

[Lower left]

Hubble took a total of 35 images of Sedna on March 16, 2004. The planetoid appeared to move slightly between exposures, due to the motion of Hubble around Earth and the motion of the Earth around the Sun. Sedna, too, is moving through space, but too slowly for that to be seen in these images. The fact that the object shows this parallax shift between exposures demonstrates that Sedna is a member of the solar system, and hence is far closer to the Earth than the background star (at right) in the same field of view.

[Top]

A plot of Sedna's apparent motion through space from 2003 to 2005 easily demonstrates that it is close enough to be part of the solar system. The looping path isn't real, but is caused by the fact that Earth is orbiting the Sun and so "laps" Sedna, like a faster race car, once every year. This gives the illusion that Sedna is briefly moving backward along its orbit. Called retrograde motion, this projection effect was noted by the ancient Greeks as they plotted the periodic backward motion of nearby Mars.

Credit: NASA, ESA and M. Brown (Caltech)

Image Type: Astronomical/Illustration
STScI-PRC2004-14a

[ 本帖最后由 活动星图 于 2007-2-25 03:29 编辑 ]

hao 顶以下

不错,顶

:shock:

一定扛~~ :twisted:  :evil:

这顶 :shock:

[quote:6c905fa6f4="活动星图"]http://www.newsmth.com/bbscon.php?bid=207&id=47955

发信人: yanxiaoxing (dpim), 信区: Astronomy
标  题: 哈勃的照片下到了
发信站: BBS 水木清华站 (Thu Apr 15 17:44:28 2004)

Sedna Mystery Deepens as Hubble Offers Best Look at Farthest Planetoid

 



This is the clearest-ever view of the farthest object yet discovered in the solar system. The object is unofficially named "Sedna" (after an Inuit goddess of the sea).

[Lower right]

At a distance of over 8 billion miles, Sedna is so far away it is reduced to one picture element (pixel) in this image, taken in high-resolution mode with Hubble's Advanced Camera for Surveys. This image sets an upper limit on Sedna's size of 1,000 miles in diameter. It is surprising that Hubble does not see a suspected moon near the planetoid. Either the moon's not there, or, far less likely, it is being eclipsed by Sedna, or it is transiting Sedna. The gravitational tug of a moon would best explain Sedna's extremely slow rotation of between 20-50 days, as inferred from ground-based photometric observations.

[Lower left]

Hubble took a total of 35 images of Sedna on March 16, 2004. The planetoid appeared to move slightly between exposures, due to the motion of Hubble around Earth and the motion of the Earth around the Sun. Sedna, too, is moving through space, but too slowly for that to be seen in these images. The fact that the object shows this parallax shift between exposures demonstrates that Sedna is a member of the solar system, and hence is far closer to the Earth than the background star (at right) in the same field of view.

[Top]

A plot of Sedna's apparent motion through space from 2003 to 2005 easily demonstrates that it is close enough to be part of the solar system. The looping path isn't real, but is caused by the fact that Earth is orbiting the Sun and so "laps" Sedna, like a faster race car, once every year. This gives the illusion that Sedna is briefly moving backward along its orbit. Called retrograde motion, this projection effect was noted by the ancient Greeks as they plotted the periodic backward motion of nearby Mars.

Credit: NASA, ESA and M. Brown (Caltech)

Image Type: Astronomical/Illustration
STScI-PRC2004-14a[/quote]
让我想起FMO    

第一回看到

[quote:889cfff9bb="ccce"]第一回看到[/quote]呵呵，这是水木社区天文版上的牛人到NASA内部要的。

嘿嘿欣赏一下咯1 ^^

看看,不错的