Friday, July 28, 2006

One of the major goals of NASA's Cassini mission was to find lakes or seas on Saturn's moon Titan.

Now scientist say they've found lakes.

These are not bodies of water like those on Earth, but rather dark lakes of methane and possibly ethane. They are likely the source of the hydrocarbon smog in the moon's atmosphere that has long made it impossible to even see the surface.

Several dark patches, some with channels running out of them, were spotted near Titan's north pole during a July 22 Cassini flyby, NASA said in a statement yesterday.

"This is a big deal," said Steve Wall, deputy radar team leader at NASA's Jet Propulsion Laboratory. "We've now seen a place other than Earth where lakes are present."

This was Cassini's first look at the region. Its radar, which penetrates the smog, was used to find several dozen lakes ranging from less than a mile wide to one that is about 62 miles long.

"What we see is darker than anything we've ever seen elsewhere on Titan. It was almost as though someone laid a bull's-eye around the whole north pole of Titan, and Cassini sees these regions of lakes just like those we see on Earth," said Larry Soderblom, Cassini interdisciplinary scientist at the U.S. Geological Survey, Flagstaff, Ariz.

On radar, dark areas indicate smoother terrain. These apparent lakes are so dark that the scientists assume they must be liquid. Any water on Titan would be constantly frozen, however, so the assumption is these lakes are made of hydrocarbons, which can stay liquid at much colder temperatures.

The shapes of outflow channels strongly suggest liquid carved them, the researchers say.

"We've always believed Titan's methane had to be maintained by liquid lakes or extensive underground 'methanofers,' the methane equivalent of aquifers," said Jonathan Lunine, a Cassini scientist at the University of Arizona. "We can't see methanofers but we can now say we've seen lakes."

Lakes should change shape slightly with the seasons, and winds ought to roughen their surfaces, so future passes by Cassini will look for these effects.

Other Cassini observations have revealed apparent river channels elsewhere on the moon, as well as shorelines that might represent lakes or seas. Scientists say the moon likely experiences methane rains.

But most observations, until now, have not shown conclusively that the methane exists in large quantities in liquid form now.

Cassini has been observing Saturn and its moons and rings since it arrived there two years ago. It is a cooperative project between NASA, the European Space Agency and the Italian Space Agency.


Tuesday, June 27, 2006

NightRide to Venus

How would you like to see a volcano erupting. Not interesting. What if its on Venus. Here is an image of the same. It definately looks like pancakes, but its actually lava seeping from underground and cooling. Creates a marvellous effect. I suppose this picture is from the Magnellan spacecraft.
Venus Express is finally in orbit around Venus. Its been circling around Venus in a elliptical orbit. SO much for science.

Wednesday, June 21, 2006

Mars Image

Gale Crater is seen in this false-color image taken by the Thermal Emission Imaging System (THEMIS), a multi-wavelength camera on NASA’s Mars Odyssey orbiter. The view combines a daytime photo taken at visible wavelengths with a nighttime infrared image. The bluish-white tones mark areas with fine-grain materials (sand, dust) thickly covering the surface, while redder tints indicate locations where harder, rockier material lies exposed. Gale Crater is one of a number of possible exploration zones for NASA’s Mars Science Laboratory to be launched in 2009. Image Credit: NASA/JPL/Arizona State University.

Tuesday, April 25, 2006

Happy 16th to Hubble

To celebrate the Hubble Space Telescope's 16 years of success, the two space agencies involved in the project, NASA and the European Space Agency (ESA), are releasing this image of the magnificent starburst galaxy, Messier 82 (M82). This mosaic image is the sharpest wide-angle view ever obtained of M82. The galaxy is remarkable for its bright blue disk, webs of shredded clouds, and fiery-looking plumes of glowing hydrogen blasting out of its central regions.

Throughout the galaxy's center, young stars are being born 10 times faster than they are inside our entire Milky Way Galaxy. The resulting huge concentration of young stars carved into the gas and dust at the galaxy's center. The fierce galactic superwind generated from these stars compresses enough gas to make millions of more stars.

In M82, young stars are crammed into tiny but massive star clusters. These, in turn, congregate by the dozens to make the bright patches, or "starburst clumps," in the central parts of M82. The clusters in the clumps can only be distinguished in the sharp Hubble images. Most of the pale, white objects sprinkled around the body of M82 that look like fuzzy stars are actually individual star clusters about 20 light-years across and contain up to a million stars.

The rapid rate of star formation in this galaxy eventually will be self-limiting. When star formation becomes too vigorous, it will consume or destroy the material needed to make more stars. The starburst then will subside, probably in a few tens of millions of years.

Located 12 million light-years away, M82 appears high in the northern spring sky in the direction of the constellation Ursa Major, the Great Bear. It is also called the "Cigar Galaxy" because of the elliptical shape produced by the oblique tilt of its starry disk relative to our line of sight.

The observation was made in March 2006, with the Advanced Camera for Surveys' Wide Field Channel. Astronomers assembled this six-image composite mosaic by combining exposures taken with four colored filters that capture starlight from visible and infrared wavelengths as well as the light from the glowing hydrogen filaments.

Hubble was launched on April 24, 1990, aboard the space shuttle Discovery.

Tuesday, April 11, 2006

NASA Adds Moon Crashing Probes to LRO Mission

NASA’s next mission to Moon will not merely orbit the gray satellite, but crash two vehicles into its South Pole to hunt for water ice, the space agency said Monday.

In addition to mapping the Moon to support future astronaut missions, NASA’s Lunar Reconnaissance Orbiter (LRO) spaceflight will also aim a spent fuel stage and impactor probe at a southern crater rich in hydrogen and, possibly, ice.

“I think aggressively touching the Moon is an understatement,” said Scott Horowitz, NASA’s associate administrator for the Exploration Systems Mission Directorate, in a Monday press conference. “What this mission buys is an early attempt to know what some of the resources we’re going to have…we know for sure that for human exploration to succeed we’re going to have to essentially live off the land.”

Astronomers know that hydrogen exists in some form on the permanently-shadowed crater floors along the Moon’s polar regions from past lunar orbiters. The Pentagon’s Clementine spacecraft hinted at water ice in a crater called Shackleton in 1994, while NASA’s Lunar Prospector unmistakable signs of hydrogen on the Moon’s surface.

NASA hopes its LRO and crash missions will provide solid answers on the presence water ice on the Moon, and whether it exists in forms that may prove useful for future astronauts. Under the space agency’s exploration vision, a four-astronaut Moon mission is slated for no later than 2020.

Lunar smash-up

Set to launch with LRO in October 2008, the $73 million Lunar Crater Observation and Sensing Satellite (LCROSS) is a bare-bones spacecraft designed to use cameras and spectrometers to watch its 4,409-pound (2,000-kilogram) upper stage slam into hydrogen-rich Shackleton Crater, mission managers said.

“It’s got the mass of an SUV and we’ll send it into the South Pole of the Moon,” LCROSS project manager Daniel Andrews, of NASA’s Ames Research Center, said of the upper stage. “We will create a substantial plume [and] excavate some sample material, some of which we think will be water ice.”

The 1,940-pound (880-kilogram) LCROSS probe will fly through the resulting plume and use its instruments to scan for water while taking photographs, then – 15 minutes after the upper stage booster’s impact – the “shepherding” satellite will also crash into the crater floor, Andrews said.

“We know that we can steer it sufficiently to sample another region of the crater,” Andrews said, adding that smashing into the same place twice would likely not yield additional valuable data.

A network of ground-based observatories will observe the impact and plume from Earth while LRO, India’s Chandrayaan-1 lunar orbiter and other spacecraft examine the Moon crash from their respective locations, LCROSS mission managers said.

Impact science

Slamming water-sniffing probes into objects is no strange feat for NASA.

The space agency crashed its Impactor probe into the comet Tempel 1 on July 4, 2005 while its parent Flyby craft and other space and ground-based observers looked on during the Deep Impact mission. NASA’s Lunar Prospector orbiter also crashed into the Moon in July 1999, also in the hope of stirring up water ice, though researchers believe it may have hit at too shallow an angle to do much science.

“The models show that it kicked up a lot of material but mostly skidded on the surface,” said Butler Hine, NASA’s Robotic Lunar Exploration Program manager, of the earlier Moon crash.

Europe’s SMART-1 orbiter – currently circling the Moon – is also expected to crash into the lunar surface later this year.

But LCROSS mission managers expect their crash-destined duo to carve a Moon crater 16 feet (4.8 meters) deep, about 100 feet (30 meters) wide and toss up about 2.2-million pounds (1,000 metric tons) of lunar material.

That’s enough lunar material to fill 10 space shuttle payload bays to the brim, Andrews said, adding that the plume could reach up to 40 miles (64 kilometers) above the lunar surface.

Lunar piggyback ride

The LCROSS mission is a late add-on to NASA’s LRO mission.

Horowitz said the secondary payload became possible when NASA decided to switch to a larger rocket booster to allow extra safety and design margin for LRO.

LCROSS was chosen after a brief competition among 19 contenders, each of which were restrained by a 2,204-pounds (1,000-kilogram) spacecraft weight cap and a cost of no more than $80 million.

NASA finally chose LCROSS out of four finalists, which included a similar Moon impact proposal that did not make use of the rocket’s upper stage, an orbital microsatellite and a small, hopping lunar lander, Horowitz said.

The key to LCROSS lies in its Moon crashing fate. Unlike LRO, which is expected to generate extremely detailed maps, the LCROSS effort will actually bite into the lunar surface at a speed of 5,592 miles per hour (or about 2.5 kilometers per second).

“You never quite know what’s there for sure until you touch it,” said Hine of the Moon’s surface. “And once we get the answer to that, it will help us plan out future human missions.”

Monday, October 10, 2005

Brown Dwarfs

Brown dwarfs in the most simplistic terms is a star remnant. It is usually 10 times Jupiter mass and maybe 3 % mass of the Sun. When the star loses its steam it starts losing its shine and become a white dwarf. What happens in a brown dwarf is that the temperature that a star must need to undergo nuclear fusions, cannot be reached. Because of that the star loses its luminosity. As the star ages its temperature goes down further and further. These stars are also called as "failed stars". So how the star remain. It has something to do with the electron degenracy pressure generated from the inside which balances out the contraction taking place. This is similar to the white dwarf, only white dwarfs have more energy. Also these stars have really high magnetic fields, due to the convective currents at the center of the star
How can one find a brown dwarf?
The popular way is what is called as the litmus test which tests for some chemical signature in the star.
Why is brown dwarfs important?
The main reason for research in brown dwarfs comes from the fact of trying to find hidden matter. It is said that only 10 % of matter has been accounted for in the universe, which makes 90 % unaccounted for. Discovery of brown dwarfs is an important step to trying to find this hidden matter.
Brown Dwarf photos:
Available at the Chandra Observatory site:

Also check:

Tuesday, October 04, 2005

The Tenth Planet

The controversy still remains whether the so-called 10th planet discovered - Xena - is a planet or just a Kuiper belt object, we hear that there is a moon which revolves around it.

For more information , follow the link