Light Eye
10-28-2004, 01:36 AM
dear friends,
another mystery in our solar system ;-)
http://www.spacedaily.com/news/cassini-04zzzr.html
be well, be love.
david
a titanic surprise
shown here are two images of the expected landing site of cassini's huygens
probe (latitude 10.6 s, longitude 191 w). at right is a wide-angle image showing
most of titan's disc, with a scale of 10 kilometers (6.2 miles) per pixel. at
left is a narrow-angle image of the landing site at a scale of 0.83 kilometers
(.5 miles) per pixel (location shown by black box at right). north is tilted
about 45 degrees from the top of both images. the surface has bright and dark
markings with a streamlined pattern consistent with motion from a fluid, such as
the atmosphere, moving from west to east (upper left to lower right). the image
at left is 400 kilometers (249 miles) wide. both images were taken by cassini's
imaging science subsystem through near-infrared filters.by henry bortman for
astrobiology magazine
moffett field (spx) oct 28, 2004
instruments aboard the cassini spacecraft have sent back the most detailed
images ever captured of the surface of saturn's giant moon, titan. they've also
presented scientists with a major mystery. there's a huge cloud formation over
the moon's south pole, spanning 1000 kilometers at its widest. that's no
surprise; scientists expected it to be there. but they also expected it to be
made of methane. and it isn't.
there's lots of methane in titan's atmosphere. it was detected many years ago by
spacecraft that flew past the ringed planet. so when recent images from the keck
observatory in hawaii showed clouds at titan's south pole, scientists assumed
they were methane clouds. according to their model, titan is so cold that
methane can form liquid pools on its surface. when this liquid is heated by the
sun, it evaporates, forming methane clouds.
water clouds on earth work the same way. the sun heats the ocean, water
evaporates and clouds form in the atmosphere. because titan's south pole is
currently pointed toward the sun, it is receiving the greatest amount of heat
right now. so a massive cloud form over the south pole fits the model perfectly
- if the cloud is made of methane.
but, according to data gathered by cassini, the particles that make up the cloud
are too big to be methane. "i don't believe it," says chris mckay, a planetary
scientist with the nasa ames research center in moffett field, california.
"what else can they be? it would be like flying over earth and saying the clouds
are not water. if those clouds are really not methane, then a lot of the things
we think about titan are wrong. a lot of things we think about those clouds are
wrong - the whole explanation of why they're there."
the cassini science team has not yet had time to fully analyze the data sent
back by the spacecraft, so they don't yet know what the clouds are made of. one
possibility, mckay speculates, is ethane. but ethane, he says, is a
photochemical product that is produced in the upper atmosphere and rains
downward. so it wouldn't make sense that a massive ethane cloud would appear at
the south pole.
another possibility, he says, is that "it's some sort of organic goo. it could
be some sort of organic polymer, essentially plastic particles. maybe little
polystyrene foam balls. who knows?" but, as with ethane, these would form from
above. there's no known reason why a massive cloud of them should form at
titan's south pole.
and so, mckay concludes, freely admitting that his off-the-cuff theory is "based
on no data," that the clouds "are formed of methane, and that there's some
process which is hiding the spectral signatures of the methane."
[non-text portions of this message have been removed]
another mystery in our solar system ;-)
http://www.spacedaily.com/news/cassini-04zzzr.html
be well, be love.
david
a titanic surprise
shown here are two images of the expected landing site of cassini's huygens
probe (latitude 10.6 s, longitude 191 w). at right is a wide-angle image showing
most of titan's disc, with a scale of 10 kilometers (6.2 miles) per pixel. at
left is a narrow-angle image of the landing site at a scale of 0.83 kilometers
(.5 miles) per pixel (location shown by black box at right). north is tilted
about 45 degrees from the top of both images. the surface has bright and dark
markings with a streamlined pattern consistent with motion from a fluid, such as
the atmosphere, moving from west to east (upper left to lower right). the image
at left is 400 kilometers (249 miles) wide. both images were taken by cassini's
imaging science subsystem through near-infrared filters.by henry bortman for
astrobiology magazine
moffett field (spx) oct 28, 2004
instruments aboard the cassini spacecraft have sent back the most detailed
images ever captured of the surface of saturn's giant moon, titan. they've also
presented scientists with a major mystery. there's a huge cloud formation over
the moon's south pole, spanning 1000 kilometers at its widest. that's no
surprise; scientists expected it to be there. but they also expected it to be
made of methane. and it isn't.
there's lots of methane in titan's atmosphere. it was detected many years ago by
spacecraft that flew past the ringed planet. so when recent images from the keck
observatory in hawaii showed clouds at titan's south pole, scientists assumed
they were methane clouds. according to their model, titan is so cold that
methane can form liquid pools on its surface. when this liquid is heated by the
sun, it evaporates, forming methane clouds.
water clouds on earth work the same way. the sun heats the ocean, water
evaporates and clouds form in the atmosphere. because titan's south pole is
currently pointed toward the sun, it is receiving the greatest amount of heat
right now. so a massive cloud form over the south pole fits the model perfectly
- if the cloud is made of methane.
but, according to data gathered by cassini, the particles that make up the cloud
are too big to be methane. "i don't believe it," says chris mckay, a planetary
scientist with the nasa ames research center in moffett field, california.
"what else can they be? it would be like flying over earth and saying the clouds
are not water. if those clouds are really not methane, then a lot of the things
we think about titan are wrong. a lot of things we think about those clouds are
wrong - the whole explanation of why they're there."
the cassini science team has not yet had time to fully analyze the data sent
back by the spacecraft, so they don't yet know what the clouds are made of. one
possibility, mckay speculates, is ethane. but ethane, he says, is a
photochemical product that is produced in the upper atmosphere and rains
downward. so it wouldn't make sense that a massive ethane cloud would appear at
the south pole.
another possibility, he says, is that "it's some sort of organic goo. it could
be some sort of organic polymer, essentially plastic particles. maybe little
polystyrene foam balls. who knows?" but, as with ethane, these would form from
above. there's no known reason why a massive cloud of them should form at
titan's south pole.
and so, mckay concludes, freely admitting that his off-the-cuff theory is "based
on no data," that the clouds "are formed of methane, and that there's some
process which is hiding the spectral signatures of the methane."
[non-text portions of this message have been removed]