Het is een regestratie formulier (ookal is het gratis)quote:
"Nou weet ik waar dat knopje voor was" ...quote:
quote:http://edition.cnn.com/2005/TECH/space/02/04/saturn.hotspot.ap/index.htmlAstronomers find Saturn 'hot spot'
Friday, February 4, 2005 Posted: 1444 GMT (2244 HKT)
HONOLULU, Hawaii (AP) --
Astronomers using a giant telescope atop a volcano
have discovered a hot spot at the tip of Saturn's south pole.
The infrared images captured by the Keck I telescope at the
W.M. Keck Observatory atop Mauna Kea on the Big Island
suggest a warm polar vortex -- a large-scale weather pattern
likened to a jet stream on Earth that occurs in the upper atmosphere.
It's the first such hot vortex ever discovered in the solar system.
A new set of infrared images suggests
a warm "polar vortex" at Saturn's south pole --
the first warm polar cap ever to be discovered
in the solar system.
The team of scientists say the images are the sharpest
thermal views of Saturn ever taken from the ground.
Their work will be a published in Friday's
editions of the journal Science.
This warm polar cap is believed to contain the highest
temperatures on Saturn; the scientists did not give a
On Earth, the Arctic Polar Vortex is typically located over
eastern North America in Canada and plunges cold arctic
air to the northern Plains in the United States.
Polar vortices are found on Earth, Jupiter, Mars and Venus,
and are colder than their surroundings.
The new images from the Keck Observatory show the first
evidence of a polar vortex at much warmer temperatures.
"Saturn's is the first hot polar vortex that we've seen because
it's been sitting in the sunlight for about 18 years," said
Glenn S. Orton, a scientist at NASA's Jet Propulsion Laboratory in
Pasadena, California, and lead author.
Saturn, which takes many earth years to orbit the sun,
just had its summer solstice in 2002.
"If the increased southern temperatures are solely the result of seasonality,
then the temperature should increase gradually with increasing latitude,
but it doesn't," Orton said. "We see that the temperature increases abruptly
by several degrees near 70 degrees south and again at 87 degrees south.
"A really hot thing within a couple degrees of the pole is something I don't
understand at all," he said.
Scientists may learn more from the data coming from the infrared
spectrometer on the Cassini spacecraft currently orbiting Saturn,
information that is expected to complement the Keck discovery, Orton said.
quote:Op dinsdag 18 januari 2005 18:23 schreef -CRASH- het volgende:
Met de radio telescopen van dwinglo hebben ze nog
"missing" data van de Huygens missie opgevangen.
quote:Scientists salvage Titan wind data
Wednesday, February 9, 2005 Posted: 1810 GMT (0210 HKT)
(SPACE.com) -- U.S. and European researchers are lauding the effectiveness of a network of ground-based telescopes that has apparently salvaged a wind experiment feared lost during a mission to the surface of Saturn's moon Titan.
Astronomers were able to use a global group of radio telescopes and a simple signal tone bleated by Europe's Huygens probe during its January 14 Titan landing to determine the moon's wind characteristics.
Early analysis of the data has given researchers a good look at the winds of Titan, despite a communications error that prevented the probe's primary data target -- NASA's Cassini orbiter currently circling Saturn -- from receiving wind observations from the Huygens probe.
"The original idea was to use Cassini's onboard receiver for Doppler ranging and later the ground stations were for a second line of sight," said Walter Brisken, a staff scientist for the National Radio Astronomy Observatory (NRAO), in a telephone interview. "But we were pretty sure we had the sensitivity needed and were fairly confident that things would work out."
Brisken worked at the NRAO's Green Bank Telescope (GBT) in West Virginia which first detected the Huygens probe's signal announcing its successful entry into Titan's atmosphere.
Other ground-based telescopes, including nine from the Very Large Baseline Array, monitored the Huygens signal. The Huygens probe itself was built by the European Space Agency (ESA).
By combining Doppler shift data from the Green Bank Telescope and other radio instruments, astronomers now know that while Titan's winds are relatively weak at the moon's surface, they reach nearly 270 miles (434 kilometer) an hour at an altitude of about 75 miles (120 kilometers).
At an altitude of about 37 miles (59 kilometers), Huygens found highly variable winds that may be a region of vertical wind shear, mission scientists said.
"I've never felt such exhilarating highs and dispiriting lows than those experienced when we first detected the signal from the GBT, indicating 'all's well' and then discovering that we had no signal at the operations center, indicating 'all's lost," said Doppler wind experiment principal investigator Michael Bird, of Germany's University of Bonn, in a written statement. "The truth, as we have now determined, lies somewhat closer to the former than the latter."
Ground-based observations of the Huygens probe's descent gave astronomers a glimpse at the north-south attributes of Titan's winds, but it was the Cassini spacecraft that was expected to return data on the moon's east-west wind patterns.
While that data is lost, Huygens researchers say the ground data was able to track the spacecraft's Titan descent to within three-quarters of a mile (one kilometer) and ultimately yield a three-dimensional picture of the probe's landing.
"It's sort of an awakening of sorts," Brisken said. "Now that we have the technology to do this so easily, it might be a more normal thing in the future."
quote:Saturn's moon frozen in time
Titan the 'Peter Pan of our solar system'[/sub
sub]Monday, February 21, 2005 Posted: 1906 GMT (0306 HKT)
(AP) -- Data from the Cassini-Huygens spacecraft suggest that Titan, a moon of Saturn, is a world with the potential of life that was frozen in its youth, prevented by deep cold from ever developing into a livelier place.
"Titan is the Peter Pan of our solar system. It's a little world that never grew up," said Tobias Owen of the University of Hawaii, a member of an international team monitoring the findings of the Huygens spacecraft sitting on Titan's surface.
The minus 292 degrees Fahrenheit (180 Celsius) temperature of Titan prevented the chemical reactions that are thought to have occurred on Earth, possibly leading to the evolution of life, said Owen, one of a group of researchers presenting papers on Titan at the national meeting of the American Association for the Advancement of Science.
"All of the elements that we are made of are there," Owen said Friday, "but all of the water is frozen solid. There's no oxygen available. If it could warm up, it would be beautiful."
Ice appears to form the bedrock of Titan, he said, and there is some suggestion of cryovolcanoes, volcanic-like vents that spew forth ice instead of lava. Owen said features detected by the Cassini spacecraft, orbiting Titan, show channels resembling volcanic features on Earth, but they may have been carved by creeping ice, not molten rock.
Owen said the evidence for ice volcanoes on Titan is "shaky," but it is the leading theory to explain some of the features seen on the body.
"We're not expecting to find life on Titan. It's just too cold," said Owen. "But we expect to find the primordial ice cream" -- the complex of chemicals that could possibly be the precursors to life.
Cassini-Huygens is a joint NASA-European Space Agency project. The combined craft was launched in 1997 and arrived in orbit of Saturn last year. Huygens, a lander developed and controlled by the ESA, touched down earlier this year.
Early studies show Titan is covered with pools of methane, an organic chemical maintained on the surface by deep cold.
Owen said that Huygens apparently landed in a "mud" formed by methane and that heat from the craft created a cloud of the gas that instruments quickly analyzed and identified.
Titan's intense cold and atmospheric pressure -- about 1 1/2 times that of Earth -- keep methane in a liquid state. Researchers earlier said there are methane showers on Titan and a methane fog.
Methane is a highly flammable gas, but there is no free oxygen on the moon to support combustion. Instead, methane flows and showers and pools.
"Methane takes the role that water does on Earth," said Owen. "And ice is like sand." He said in Titan's intense cold, chips of ground ice could be like beach sand, drifting with the flow of methane.
Dennis Matson of NASA's Jet Propulsion Laboratory said that ice forms the bedrock of Titan and that sometime during the formation of the moon the frozen water may have warmed enough to flow to the surface like lava in a volcano on Earth.
"It would be the consistency of magma. At some temperatures below freezing, ice is pliable," he said. "It could flow like toothpaste out of a tube."
Matson emphasized that the ice volcano concept is still a theory, but it offers the best explanation for some features seen on the surface of Titan.
Scientists at the conference also reported on the progress of Spirit and Opportunity, two rolling robots that have been exploring the surface of Mars for more than a year.
Steven W. Squyres of Cornell University, one of the principal scientists on the Martian rover mission, said Spirit took a self-portrait with one of its cameras that shows the craft's solar power panels coated with a reddish grime. This cuts down on the amount of sunlight the craft can use to make electrical power.
"It is so dirty that it is important that we always orient it toward the sun," said Squyres. "We are slaves to the sun."
A self-portrait by Opportunity shows that its solar panels are clean, "like it's just off the showroom floor," Squyres said.
Spirit, which is slowly exploring the north flank of a Martian hill named Husband, has found bedrock sticking out of the red soil. It also churned up surface soil, and pictures sent to Earth show a layer of "bright stuff" that Squyres said is probably a type of sulfur salt.
The rover also photographed layers of fragile-appearing light rock that researchers believe is basaltic sand glued together with a magnesium-sulphur salt.
Such a process could occur in a pool of water, said Squyres. Earlier studies have shown that liquid water once flowed in great quantities on Mars, but the planet's surface is now very dry.
quote:BRON: Cassini probe detects Enceladus atmosphere
Wednesday, March 16, 2005 Posted: 2053 GMT (0453 HKT)
The Cassini spacecraft's two flybys of Saturn's icy moon Enceladus have revealed that the moon has a significant atmosphere.
LOS ANGELES, California (Reuters) -- The space probe Cassini discovered a significant atmosphere around Saturn's moon Enceladus during two recent passes close by, the Jet Propulsion Laboratory said on Wednesday.
Scientists speculate the atmosphere comes from volcanoes, geysers or some other kind of sub-surface activity, JPL said in a statement.
"These new results from Cassini may be the first evidence of gases originating either from the surface or possibly from the interior of Enceladus," said Dr. Michele Dougherty, principal investigator for the Cassini magnetometer and professor at Imperial College in London.
Cassini made passes on February 17 and March 9 and discovered the atmosphere using a magnetometer, which discovered a magnetic field on the moon.
Because gravity is weak on Enceladus, a continuous source is needed to maintain the atmosphere, JPL said. The 310-mile-wide (500-km-wide) moon is icy and considered the most reflective object in the solar system, bouncing back about 90 percent of the sunlight that hits it.
Titan, another moon of Saturn, also has a substantial atmosphere. The European probe Huygens, which went to Saturn piggy-back on Cassini, landed on Titan in January.
Cassini-Huygens is a joint venture of NASA, the European Space Agency and the Italian Space Agency. Scientists at JPL designed, developed and built Cassini.
Je moet je niet vergissen. Maar hier op aarde zijn microben die in zuren, hoge en lage temperaturen kunnen overleven.quote:Op donderdag 9 maart 2006 22:58 schreef Speth het volgende:
veel interessanter dan de onwaarschijnlijke aanwezigheid van wat microben...
Weinig....quote:Op donderdag 9 maart 2006 23:17 schreef speknek het volgende:
Ik blijf het suf vinden dat er maar zo weinig en slechte foto's van Huygens afgekomen zijn, totnutoe althans.
Maar die zijn daar naar alle waarschijnlijkheid niet ontstaan, maar hebben zich geleidelijk aan aangepast aan die omstandigheden. Dat zoiets ontstaat in een kolkende massa water omgeven door ijs, waarvan om de zoveel tijd een paar duizend liter van naar buiten spuit, en waarin waarschijnlijk weinig organisch materiaal is te vinden is nogal vergezocht..quote:Op donderdag 9 maart 2006 23:14 schreef -CRASH- het volgende:
Je moet je niet vergissen. Maar hier op aarde zijn microben die in zuren, hoge en lage temperaturen kunnen overleven.
Bij de geisers in Yellowstone zijn bacterieŽn die 300 boven de kook temperatuur leven
en bij een PH waarde van 0.
Kloptquote:Op donderdag 9 maart 2006 23:43 schreef speknek het volgende:
Ligt het aan mij of zijn dat Cassini foto's?
Moet je Vrijdag om 14:00 naar NGC kijken naar:quote:Op vrijdag 10 maart 2006 00:05 schreef Speth het volgende:
Maar die zijn daar naar alle waarschijnlijkheid niet ontstaan, maar hebben zich geleidelijk aan aangepast aan die omstandigheden.
De theorie van de komeetinslagen die ons water hebben gebracht klinkt me altijd vrij onzinnig in de oren... De hoeveelheid inslagen die nodig is lijkt me te hoog, het aantal komeetinslagen van dergelijke omvang dat vandaag de dag voorkomt is zeer klein, en Jupiter bestond ook toen al om dat soort objecten op te vangen. Bovendien is op bijna alle planeten wel water aanwezig, of aanwezig geweest, waarom zou dat per se van kometen afkomstig moeten zijn, en waarom zou het niet al aanwezig kunnen zijn bij de vorming van die lichamen?quote:Op vrijdag 10 maart 2006 00:26 schreef -CRASH- het volgende:
Moet je Vrijdag om 14:00 naar NGC kijken naar:
Mysterious Universe: Killers In Space
Daar wordt het uitgelegd hoe er leven ontstaan is op aarde
Ik dacht me herinneren dat het een combinatie van beiden was ... chemische reactie in geisers en komeet inslagen.