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Collection:
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NASA Astronomy Picture of the Day Collection
Collection
NASA Astronomy Picture of the Day Collection
Collection
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Title:
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Dione's Lagrange Moon Helene
Title
Dione's Lagrange Moon Helene
Title
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Explanation:
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Saturn [ http://antwrp.gsfc.…]'s moon Helene [ http://www.c3.lanl.…] is very unusual in that it circles Saturn [ http://antwrp.gsfc.…] near the orbit of a bigger moon: Dione [ http://antwrp.gsfc.…]. Helene is situated in what is called a "Lagrange point" of Dione - a place of stability created by Dione's gravity. Were Helene [ http://seds.lpl.ari…] to stray slightly from its orbit 1/6 ahead of Dione, the larger moon's gravity would cause Helene to move back toward the Lagrange point. Many massive orbital bodies have stable Lagrange points, including the Earth and Moon. Helene was discovered from the ground by P. Laques & J. Lecacheux in 1980. The photograph above was taken by Voyager 2 as it passed Saturn in 1981. NASA's Cassini [ http://newproducts.…] mission to Saturn is currently scheduled for launch in October 1997.
Explanation
Saturn [ http://antwrp.gsfc.…]'s moon Helene [ http://www.c3.lanl.…] is very unusual in that it circles Saturn [ http://antwrp.gsfc.…] near the orbit of a bigger moon: Dione [ http://antwrp.gsfc.…]. Helene is situated in what is called a "Lagrange point" of Dione - a place of stability created by Dione's gravity. Were Helene [ http://seds.lpl.ari…] to stray slightly from its orbit 1/6 ahead of Dione, the larger moon's gravity would cause Helene to move back toward the Lagrange point. Many massive orbital bodies have stable Lagrange points, including the Earth and Moon. Helene was discovered from the ground by P. Laques & J. Lecacheux in 1980. The photograph above was taken by Voyager 2 as it passed Saturn in 1981. NASA's Cassini [ http://newproducts.…] mission to Saturn is currently scheduled for launch in October 1997. Explanation
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Credit and Copyright:
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Credit_and_Copyright
Credit and Copyright
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facet_when:
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1981
facet_when
1981
facet_when
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facet_when:
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1980
facet_when
1980
facet_when
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facet_when:
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October 1997
facet_when
October 1997
facet_when
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facet_where:
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Arizona
facet_where
Arizona
facet_where
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facet_where:
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Saturn
facet_where
Saturn
facet_where
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facet_where:
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Dione
facet_where
Dione
facet_where
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facet_where:
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Goddard Space Flight Center (GSFC)
facet_where
Goddard Space Flight Center (GSFC)
facet_where
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facet_where:
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Jet Propulsion Laboratory (JPL)
facet_where
Jet Propulsion Laboratory (JPL)
facet_where
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facet_what:
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Earth
facet_what
Earth
facet_what
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facet_what:
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Voyager
facet_what
Voyager
facet_what
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facet_what:
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Moon
facet_what
Moon
facet_what
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facet_what:
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Saturn
facet_what
Saturn
facet_what
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facet_what:
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Cassini
facet_what
Cassini
facet_what
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facet_what:
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Voyager 2
facet_what
Voyager 2
facet_what
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facet_what:
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Dione
facet_what
Dione
facet_what
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facet_what:
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moon
facet_what
moon
facet_what
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facet_when_year:
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1997
facet_when_year
1997
facet_when_year
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facet_when_year:
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1980
facet_when_year
1980
facet_when_year
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facet_when_year:
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1981
facet_when_year
1981
facet_when_year
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original url:
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original_url
original url
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UID:
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SPD-APOD-ap951010
UID
SPD-APOD-ap951010
UID
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