MessageToEagle.com - NASA's Cassini spacecraft has spied long-standing methane lakes, or puddles, in the "tropics" of
Saturn's moon Titan. One of the tropical lakes appears to be about half the size of Utah's Great Salt Lake, with a depth of
at least 3 feet (1 meter).
The result, which is a new analysis of Cassini data, is unexpected because models had assumed the long-standing bodies
of liquid would only exist at the poles. The findings appear in this week's issue of the journal Nature.
Where could the liquid for these lakes come from? "A likely supplier is an underground aquifer," said Caitlin Griffith,
the paper's lead author and a Cassini team associate at the University of Arizona, Tucson.
"In essence, Titan may have oases."
Understanding how lakes or wetlands form on Titan helps scientists learn about the moon's weather. Like Earth's
hydrological cycle, Titan has a "methane" cycle, with methane rather than water circulating. In Titan's atmosphere, ultraviolet
light breaks apart methane, initiating a chain of complicated organic chemical reactions. But existing models haven't been
able to account for the abundant supply of methane.
"An aquifer could explain one of the puzzling questions about the existence of methane, which is continually depleted,"
Griffith said. "Methane is a progenitor of Titan's organic chemistry, which likely produces interesting molecules like
amino acids, the building blocks of life."
Global circulation models of Titan have theorized that liquid methane in the moon's equatorial region evaporates and is
carried by wind to the north and south poles, where cooler temperatures cause methane to condense. When it falls to the
surface, it forms the polar lakes.
The existence of oceans or lakes of liquid methane on Saturn's moon Titan was predicted more than 20 years ago.
But with a dense haze preventing a closer look it has not been possible to confirm their presence. Until the Cassini
flyby of July 22, 2006, that is.
Radar imaging data from the flyby, published this week in the journal Nature, provide convincing evidence for large
bodies of liquid. This image, used on the journal's cover, gives a taste of what Cassini saw. Intensity in this colorized image
is proportional to how much radar brightness is returned, or more specifically, the logarithm of the radar backscatter cross-section.
The colors are not a representation of what the human eye would see.
The lakes, darker than the surrounding terrain, are emphasized here by tinting regions of low backscatter in blue.
Radar-brighter regions are shown in tan. The strip of radar imagery is foreshortened to simulate an oblique view of
the highest latitude region, seen from a point to its west.
This radar image was acquired by the Cassini radar instrument in synthetic aperture mode on July 22, 2006. The image
is centered near 80 degrees north, 35 degrees west and is about 140 kilometers (84 miles) across. Smallest details
in this image are about 500 meters (1,640 feet) across. Credits: NASA/Cassini
On Earth, water is similarly transported by the circulation, yet the oceans also transport water, thereby countering
the atmospheric effects.
The latest results come from Cassini's visual and infrared mapping spectrometer, which detected the dark areas in the
tropical region known as Shangri-La, near the spot where the European Space Agency's Huygens probe landed in 2005.
When Huygens landed, the heat of the probe's lamp vaporized some methane from the ground, indicating it had landed in a damp area.
Areas appear dark to the visual and infrared mapping spectrometer when liquid ethane or methane are present.
Some regions could be shallow, ankle-deep puddles. Cassini's radar mapper has seen lakes in the polar region, but hasn't
detected any lakes at low latitudes.
The tropical lakes detected by the visual and infrared mapping spectrometer have remained since 2004. Only once has rain
been detected falling and evaporating in the equatorial regions, and only during the recent expected rainy season.
Scientists therefore deduce the lakes could not be substantively replenished by rain.
"We had thought that Titan simply had extensive dunes at the equator and lakes at the poles, but now we know that Titan
is more complex than we previously thought," said Linda Spilker, the Cassini project scientist based at NASA's Jet Propulsion
Laboratory, Pasadena, Calif.
"Cassini still has multiple opportunities to fly by this moon going forward,
so we can't wait to see how the details of this story fill out."
"The Most Profound Mystery In All Of Science" -
Little is known about this force and its its repulsive gravity, which is causing the expansion of the universe to accelerate.
The riddles of dark matter and cosmic inflation, along with dark energy, these are the three pillars of modern cosmological theory,"
and none of them can be explained with physics that we know," Michael Turner, director of the Kavli Institute for Cosmological Physics says.
Last Breaths Of Dying Star Captured
Last breaths of dying sun-like star have been captured by scientists using NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA).
The object observed by SOFIA, planetary nebula Minkowski 2-9, or M2-9 for short, is seen in this three-color composite image.
The SOFIA observations were made at the mid-infrared wavelengths of 20, 24, and 37 microns.
The Moon Is Not Earth's Only Natural Satellite
The Earth constantly captures small objects from (to) the NEO population and scientists construct a steady-state model of the Earth's temporary satellites.
According to their studies, at any given time there is at least one one-meter-diameter object orbiting the Earth and the average satellite makes
about 3 revolutions around the Earth in 9 months.
Alien Species Living In The Inner Milky Way Could Be In Danger
Few people doubt there is intelligent alien life in the Milky Way galaxy, but where can we expect to find it?
Astronomers think that while the inner sector of the MIlky Way Galaxy may be the most likely to support habitable worlds.
Unfortunately some of these places are also most dangerous to all life-forms.
Black Holes With No 'Table Manners' Eat Two Courses At Once!
It is still unknown how the supermassive black holes (SMBH) in galaxy centres accrete gas and grow.
Researchers from the University of Leicester (UK) and Monash University in Australia have investigated how some black holes got so big so fast that they are billions of times heavier than the sun.
Mercury Surprises Scientists
On March 17, MESSENGER (MErcury Surface, Space Environment, GEochemistry, and Ranging) completed its one-year primary mission, orbiting Mercury, capturing nearly 100,000 images, and recording data
that reveals new information about the planet's core, topography, and the mysterious radar bright material in the permanently shadowed areas near the poles.
Living Earth Simulator - Supercomputer Predicting The Future
In Douglas Adams book the Hitchhikers Guide to the Galaxy we encounter a machine called Deep Thought. It is the most powerful computer ever built. Deep Thought is capable of answering questions
concerning life, the Universe, and simply everything. Now scientists are planning to create a similar machine. It is called the Living Earth Simulator (LES).
Though the universe is filled with billions upon billions of stars, the discovery of a single variable star in 1923 altered the
course of modern astronomy. And, at least one famous astronomer of the time lamented that the discovery had shattered his world view.