சனிக்கோளைச் சுற்றி உள்ள மாபெரும் வளையம்

by nandhtiha Wed Oct 14, 2009 5:03 pm

Spitzer Discovers
Saturn's Largest Ring

10.07.2009

October
7, 2009: NASA's Spitzer Space Telescope has discovered
an enormous and previously unknown infrared ring around Saturn.
"This
is one supersized ring," says Anne Verbiscer, an astronomer
at the University of Virginia, Charlottesville. "If you
could see the ring in the night sky, it would span the width
of two full Moons."
Verbiscer
is co-author of a paper about the discovery to be published
online tomorrow by the journal Nature. The other
authors are Douglas Hamilton of the University of Maryland
and Michael Skrutskie of the University of Virginia.

சனிக்கோளைச் சுற்றி உள்ள மாபெரும் வளையம் 392150main_spitzer20091006-516

Above:
An artist's concept of the newly-discovered infrared ring
around Saturn. [more]
The
new belt lies at the far reaches of the Saturnian system,
with an orbit tilted 27 degrees from the main ring plane.
The bulk of its material starts about six million kilometers
(3.7 million miles) away from the planet and extends outward
roughly another 12 million kilometers (7.4 million miles).
It would take about one billion Earths stacked together to
fill the voluminous ring. One of Saturn's farthest moons,
Phoebe, circles within the newfound ring, and is likely the
source of its material.

சனிக்கோளைச் சுற்றி உள்ள மாபெரும் வளையம் Newshat

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The
ring is tenuous, consisting of widely-dispersed particles of
ice and dust. Spitzer's infrared eyes were able to spot the
glow of the cool dust, which has a temperature of only about
80 Kelvin (minus 316 degrees Fahrenheit).
The
discovery may help solve an age-old riddle of one of Saturn's
moons. Iapetus has a strange appearance — one side is bright
and the other is really dark, in a pattern that resembles
the yin-yang symbol. The astronomer Giovanni Cassini first
spotted the moon in 1671, and years later figured out it has
a dark side, now named Cassini Regio in his honor.
Saturn's
supersized ring could explain how Cassini Regio came to be
so dark. The ring is circling in the same direction as Phoebe,
while Iapetus, the other rings and most of Saturn's moons
are all going the opposite way. According to the scientists,
some of the dark and dusty material from the outer ring moves
inward toward Iapetus, slamming the icy moon like bugs on
a windshield.

சனிக்கோளைச் சுற்றி உள்ள மாபெரும் வளையம் PIA08384_modest_med

"Astronomers
have long suspected that there is a connection between Saturn's
outer moon Phoebe and the dark material on Iapetus,"
said Hamilton. "This new ring provides [the missing link]."

Right:
Saturn's moon Iapetus. One side of the moon is darkened as
the moon plows through the dust of Saturn's newly-discovered
infrared ring. [more]
Verbiscer
and colleagues used Spitzer's longer-wavelength infrared camera,
called the multiband imaging photometer, to scan through a
patch of sky far from Saturn and a bit inside Phoebe's orbit.
The astronomers had a hunch that Phoebe might be circling
around in a belt of dust and, sure enough, when the scientists
took a first look at their Spitzer data, a band of dust jumped
out.
The
ring would be difficult to see with visible-light telescopes.
The relatively small numbers of particles in the ring wouldn't
reflect much visible light, especially out at Saturn where
sunlight is weak.
"The
particles are so far apart that if you were to stand in the
ring, you wouldn't even know it," said Verbiscer. "By
focusing on the glow of the ring's cool dust, Spitzer made
it easy to find."
For
additional images relating to the ring discovery and more

information about Spitzer, visit http://www.spitzer.caltech.edu.

by **Manik** Wed Oct 14, 2009 5:06 pm

அக்கா வளையம் ஓகே அதனால என்ன பிரச்சினைனு தமிழ்ல எழுதுங்கக்கா........ ஒன்னுமே புரியல

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