A Ghostly Presence
This composite image shows Z Camelopardalis, or Z Cam, a double-star system. The Z Cam system features a collapsed, dead star, called a white dwarf, and its companion star, as well as a ghostly shell around the system. The massive shell provides evidence of lingering material ejected during, and swept up by, a powerful explosion that occurred a few thousand years ago.

The image combines data gathered
from the far-ultraviolet and near-ultraviolet detectors on NASA's Galaxy Evolution Explorer on Jan. 25, 2004. The orbiting observatory first began imaging Z Cam in 2003.

Z Cam is the largest white object in the image, located near the center. Parts of the shell are seen as a wispy, yellowish feature below and to the right of Z Cam, and as two large, whitish, perpendicular lines on the left.

Z Cam was one of the first known recurrent dwarf nova, meaning it
erupts in a series of small, hiccup-like blasts, unlike classical novae, which undergo a massive explosion.

Image credit: NASA/JPL-Caltech

The Colors of Saturn
This delightfully detailed false color image of Saturn is a combination of three images taken in January 1998 by the Hubble Space Telescope and shows the ringed planet in reflected infrared light. Different colors indicated varying heights and compositions of cloud layers generally thought to consist of ammonia ice crystals. The eye-catching rings cast a shadow on Saturn's upper hemisphere, while the bright stripe seen within the left portion of the shadow is infrared
sunlight streaming through the large gap in the rings known as the Cassini Division.

Two of Saturn's many moons have also put in an appearance (in the full resolution version), Tethys just beyond the planet's disk at the upper right, and Dione at the lower left.

Image credit: NASA/E. Karkoschka (University of Arizona)

Jet Power
This dramatic image of the nearby galaxy Centaurus A provides one of the best views to date of the effects of an active supermassive black hole. Opposing jets of high-energy particles can be seen extending to the outer reaches of the galaxy, and numerous smaller black holes in binary star systems are also visible.

The image obtained via an ultra-deep look at the galaxy by the Chandra X-Ray Observatory that
was equivalent to more than seven days of continuous observations. Centaurus A is the nearest galaxy to Earth that contains a supermassive black hole actively powering a jet.

A prominent X-ray jet extending for 13,000 light years points to the upper left in the image, with a shorter "counterjet" aimed in the opposite direction. Astronomers think that such jets are important vehicles for transporting energy from the black hole to the much larger dimensions of a galaxy, and affecting the rate at which stars form there.

Image Credit: NASA/CXC/CfA/R. Kraft et al.

Galaxies of All Shapes and Sizes
This artist's concept illustrates the two types of spiral galaxies that populate our universe: those with plump middles, or central bulges (upper left), and those without them (foreground).

New observations from NASA's Spitzer Space Telescope provide strong evidence that the slender, bulgeless galaxies can, like their chubbier counterparts, harbor supermassive black holes at their
cores. Previously, astronomers thought that a galaxy without a bulge could not have a supermassive black hole. The findings are reshaping theories of galaxy formation.

Image Credit: NASA/JPL-Caltech

Dwarf Galaxies in the Coma Cluster
In visible light images, more than a thousand galaxies are seen to lie within a volume about 20 million light-years across in the rich Coma Galaxy Cluster. But infrared images of the Coma Cluster are now being used to add thousands more to the Coma's galaxy count in the form of previously undiscovered dwarf galaxies.

This composite combines infrared Spitzer Space Telescope image
data (red and green) with visible light Sloan Sky Survey data (blue) for the central part of the cluster. Over 1 degree wide, the field is dominated by two giant elliptical galaxies in blue. Still, many of the small green smudges are identified as dwarf galaxies, roughly comparable to the Small Magellanic Cloud. Dwarf galaxies are thought to form first, providing building blocks for larger galaxies. The well-studied, friendly, Coma Cluster is 320 million light-years away.

Image Credit: NASA, JPL-Caltech, SDSS, Leigh Jenkins, Ann

Chrysalis
As if emerging from a cocoon, space shuttle Atlantis races into the sky on mission STS-122 to the International Space Station. The launch is the third attempt for Atlantis since December 2007 to carry the European Space Agency's Columbus laboratory to the International Space Station. During the 11-day mission, the crew's prime objective is to attach the laboratory to the Harmony module, adding to the station's size and capabilities.

Image Credit: NASA/Sandra Joseph, Tony Gray, Robert Murray

A Classic Beauty
M51, whose name comes from being the 51st entry in Charles Messier's catalog, is considered to be a classic example of a spiral galaxy. At a distance of about 30 million light years from Earth, it is also one of the brightest spirals in the night sky. A composite image of M51, also known as the Whirlpool Galaxy, shows the majesty of its structure in a dramatic new way through several of NASA's orbiting observatories. X-ray data from NASA's Chandra X-ray Observatory
reveals point-like sources (purple) that are black holes and neutron stars in binary star systems. Chandra also detects a diffuse glow of hot gas that permeates the space between the stars. Optical data from the Hubble Space Telescope (green) and infrared emission from the Spitzer Space Telescope (red) both highlight long lanes in the spiral arms that consist of stars and gas laced with dust. A view of M51 with the GALEX telescope shows hot, young stars that produce lots of ultraviolet energy (blue).
The textbook spiral structure is thought be the result of an interaction M51 is experiencing with its close galactic neighbor, NGC 5195, which is seen just above (in the full size image).

Image credit: X-ray: NASA/CXC/Wesleyan Univ./R. Kilgard; UV: NASA/JPL-Caltech; Optical: NASA/ESA/S. Beckwith & The Hubble Heritage Team (STScI/AURA); IR: NASA/JPL-Caltech/Univ. of Az/R. Kennicutt

Food, fuel and shelter: vegetation is one of the most important requirements for human populations around the world. Satellites monitor how "green" different parts of the planet are and how that greenness changes over time. These observations help scientists understand the influence of natural cycles, such as drought and pest outbreaks, on vegetation, as well as human influences, such as land-clearing and global warming.
One method of mapping the difference in vegetation is a measurement known as the Normalized Difference Vegetation Index (NDVI). This image shows NDVI from Nov. 1, 2007, to Dec. 1, 2007, during autumn in the Northern Hemisphere. This monthly average is based on observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite.

The greenness values on this global map range from -0.1 to 0.9, but have no actual unit. Instead,
higher values (dark greens) show land areas with plenty of leafy green vegetation, such as the Amazon Rainforest. Lower values (beige to white) show areas with little or no vegetation, including sand seas and Arctic areas. Areas with moderate amounts of vegetation are pale green. Land areas with no data appear gray, and water appears blue.

Image Credit: NASA

Between Earth and Space
Astronaut Robert L. Behnken, STS-123 mission specialist, participates in the mission's third scheduled spacewalk. During the 6-hour, 53-minute spacewalk, Behnken and Rick Linnehan installed a spare-parts platform and tool-handling assembly for Dextre, also known as the Special Purpose Dextrous Manipulator. Among other tasks, they also checked out and calibrated Dextre's end effector and attached critical spare parts to an external stowage platform. The new robotic system was activated on a power and data grapple fixture located on the Destiny laboratory on flight day nine. The blackness of space and Earth's horizon provide the backdrop for the scene.

Image Credit: NASA

Thunderbirds and Endeavour
The U.S. Air Force Thunderbirds fly past Launch Pad 39A at NASA's Kennedy Space Center in commemoration of NASA's 50th anniversary. The aircraft had flown earlier to support the Daytona 500, also celebrating its 50th anniversary, and chose to fly over Kennedy on their way to their next assignment. On the pad, space shuttle Endeavour waits to launch on the STS-123 mission.

Image Credit: USAF/TSgt. Justin D. Pyle

Angels Overhead
Employees at NASA's Kennedy Space Center in Florida are accustomed to seeing a lot of action in the skies overhead. But there was something unusual in the airspace on April 7: a sleek F/A-18 Hornet aircraft, one of the U.S. Navy's famed Blue Angels.

The team was on hand to make preparations for the 2008 Space & Air Show at Kennedy Space Center, which is set for Nov. 8 and 9. Hosted by the Kennedy Space
Center Visitor Complex, the 2008 show will feature several aerial demonstrations in addition to the Blue Angels, including an astronaut rescue simulation performed by the 920th Rescue Wing based at nearby Patrick Air Force Base. In addition to the action in the air, aircraft and space-related exhibits will be displayed on the ground in the viewing area. Astronauts from the Mercury, Gemini, Apollo and Space Shuttle programs will be available for autographs and photos Image Credit: NASA/Kim Shiflet .

JFK Receives Mariner Model
William H. Pickering, (center) director of NASA's Jet Propulsion Laboratory, presents a model of the Mariner spacecraft to President John F. Kennedy in 1961. NASA Administrator James Webb is standing directly behind the model.

Image Credit: NASA

Phoenix: Bound for Mars
A Delta II rocket lit up the early morning sky over Cape Canaveral Air Force Station in Florida as it carried the Phoenix spacecraft on the first leg of its journey to Mars. The powerful three-stage rocket with nine solid rocket motors lifted off at 5:26 a.m. EDT on Aug. 4.

Image credit: NASA

Phoenix: Bound for Mars
A Delta II rocket lit up the early morning sky over Cape Canaveral Air Force Station in Florida as it carried the Phoenix spacecraft on the first leg of its journey to Mars. The powerful three-stage rocket with nine solid rocket motors lifted off at 5:26 a.m. EDT on Aug. 4.

Image credit: NASA

* Astrônomos * Image credit: NASA

STS-118: The Mission Begins
The STS-118 crew recently took a break from traing to pose for their official portrait. Pictured from the left are Rick Mastracchio, Barbara R. Morgan, pilot Charles Hobaugh, mission commander Scott Kelly, Tracy Caldwell, Canadian Space Agency astronaut Dave Williams and Alvin Drew. The mission is slated to launch today, Aug. 8, 2007, at 6:36 p.m. EDT.

Image credit: NASA

The Egg Nebula
Where is the center of the Egg Nebula? Like a baby chick pecking its way out of an egg, the star in the center of the Egg Nebula is casting away shells of gas and dust as it slowly transforms itself into a white dwarf star.

The Egg Nebula is a rapidly evolving pre-planetary nebula spanning about one light year toward the constellation of Cygnus. Thick dust blocks the center star from view, while the dust shells

further out reflect light from this star. Light vibrating in the plane defined by each dust grain, the central star and the observer is preferentially reflected, causing an effect known as polarization. Measuring the orientation of the polarized light for the Egg Nebula gives clues as to location of the hidden source. The above image taken by the Advanced Camera for Surveys on the Hubble Space Telescope is false-color coded to highlight the orientation of polarization.

Image credit: NASA, W. Sparks (STScI) and R. Sahai (JPL)

* Sahra Desert *

Terkezi Oasis
Dominating the top third of Africa is the Sahra Desert, Earth's largest band of dry land. Stretching across the Sahara are vast plains of sand and gravel, seas of sand dunes and barren rocky mountains.

Only 10,000 years ago grasses covered the region and mammals such as lions and elephants roamed the land. Now only two percent of the Sahara hosts oases, patches of land usually centered on natural water springs where crops

will grow and where nearly two million people live. This image, taken by Landsat 7, is of a colorful and rocky expanse spanning about 50 kilometers near the Terkezi Oasis in Chad.

Image credit: NASA

From the Sun
Hinode, a collaborative mission of the space agencies of Japan, the United States, United Kingdom and Europe, captured these very dynamic pictures of our sun's chromosphere on Jan. 12, 2007. Taken by Hinode's Solar Optical Telescope, this image of the sun reveals the filamentary nature of the plasma connecting regions of different magnetic polarity. The chromosphere is a thin layer of solar atmosphere sandwiched between the visible surface,
photosphere and corona.

Image credit: JAXA/NASA

Dusty Environs of Eta Carinae
Eta Car is a massive star, but it's not as bright as it used to be. Now visible only in binoculars or a small telescope, Eta Carinae has a history of spectacular flaring and fading behavior.

In fact, in April of 1843 Eta Car briefly became second only to Sirius as the brightest star in planet Earth's night sky, even though at a distance of about 7,500 light-years, it is about 800 times farther away. Surrounded by a complex and
evolving nebula, Eta Carinae is seen near the center of this false-color infrared image, constructed using data from the Midcourse Space Experiment satellite, which mapped the galactic plane in 1996.

In the picture, wispy, convoluted filaments are clouds of dust glowing at infrared wavelengths. Astronomers hypothesize that Eta Car itself will explode as a supernova in the next million years. Massive Eta Car is considered a candidate for a hypernova explosion and the potential source of future gamma-ray bursts.

Image credit: NASA

Sun Storm!
The sun-orbiting SOHO spacecraft has imaged many erupting filaments lifting off the active solar surface and blasting enormous bubbles of magnetic plasma into space. This image shows the sun in ultraviolet light, while the field of view extends over 2 million kilometers, or 1.243 million miles, from the solar surface.

While hints of these explosive sun storms, called coronal mass ejections or CMEs, were discovered
by spacecraft in the early 1970s, this dramatic image is part of a detailed record of this CME's development from the presently operating SOHO spacecraft. At a minimum, solar activity cycle CMEs occur about once a week, with maximum rates of two or more per day. Strong CMEs may profoundly influence space weather and those directed toward our planet can have serious effects.

Image credit: NASA/JPL

Dusty Stellar Nursery Revealed
How can something as big as a star go undetected? The answer is dust. Stellar nursery DR21 is shrouded in so much space dust that no visible light escapes it. By seeing in the infrared, NASA's Spitzer Space Telescope pulls this veil aside. The new observations reveal a firework-like display of massive stars surrounded by a stormy cloud of gas and dust. The biggest star is estimated to be 100,000 times as bright as our own
sun.


Image credit: NASA/JPL/Caltech

Cosmic Epic Unfolds in Infrared
This majestic view, taken by NASA's Spitzer Space Telescope, tells an untold story of life and death in the Eagle Nebula, an industrious star-making factory located 7,000 light-years away in the Serpens Constellation. The image shows the region's entire network of turbulent clouds and newborn stars in infrared light.

The color green denotes cooler towers and fields of dust, including
the three famous space pillars, dubbed the "Pillars of Creation," which were photographed by NASA's Hubble Space Telescope in 1995 (right of center; see http://www.nasa.gov/mission_pages/spitzer/multimedia/ssc2007-01b.html for exact location).

But it is the color red that speaks of the drama taking place in this region. Red represents hotter dust thought to have been warmed by the explosion of a massive star about 8,000 to 9,000 years ago. Since light from the Eagle Nebula takes 7,000 years to reach us, this 7,000 years to reach us, this supernova explosion would have appeared as an oddly bright star in our skies about 1,000 to 2,000 years ago.

According to astronomers' estimations, the explosion's blast wave would have spread outward and toppled the three pillars about 6,000 years ago (which means we wouldn't witness the destruction for another 1,000 years or so). The blast wave would have crumbled the mighty towers, exposing newborn stars that were buried inside, and triggering the birth of new ones.

Image credit: NASA/JPL-Caltech/ Institut d'Astrophysique Spatia

NGC 602 and Beyond
Near the outskirts of the Small Magellanic Cloud, a satellite galaxy some 200 thousand light-years distant, lies the young star cluster NGC 602. Surrounded by natal gas and dust, NGC 602 is featured in this Hubble image of the region. Fantastic ridges and undulating shapes strongly suggest that energetic radiation and shock waves from NGC 602's massive young stars have eroded the dusty material and triggered a progression of star formation

moving away from the cluster's center. At the estimated distance of the Small Magellanic Cloud, the picture spans about 200 light-years, but a tantalizing assortment of background galaxies are also visible in the sharp Hubble view. The background galaxies are hundreds of millions of light-years or more beyond NGC 602.

Image credit: NASA, ESA and the Hubble Heritage Team (STScI / AURA)

Burning Brightly
Images from the Hubble space Telescope, Spitzer Space Telescope and Chandra X-Ray Observatory combine to make this composite of N49, the brightest supernova remnant in optical light in the Large Magellanic Cloud. The Chandra X-ray image (blue) shows million-degree gas in the center. Much cooler gas at the outer parts of the remnant is seen in the infrared image from Spitzer (red). While astronomers expected that dust particles were generating most
of the infrared emission, the study of this object indicates that much of the infrared is instead generated in heated gas.

The unique filamentary structure seen in the optical image by Hubble (white and yellow) has long set N49 apart from other supernova remnants, as most appear roughly circular in visible light. Recent mapping of molecular clouds suggests that this supernova remnant is expanding into a denser region to the southeast, which would cause its asymmetrical
appearance. This idea is confirmed by the Chandra data. Although x-rays reveal a round shell of emission, the they also show brightening in the southeast, confirming the idea of colliding material in that area.

Image credit: NASA/CXC/STScI/JPL-Caltech/UIUC/Univ. of Minn.

Burning Brightly
Images from the Hubble space Telescope, Spitzer Space Telescope and Chandra X-Ray Observatory combine to make this composite of N49, the brightest supernova remnant in optical light in the Large Magellanic Cloud. The Chandra X-ray image (blue) shows million-degree gas in the center. Much cooler gas at the outer parts of the remnant is seen in the infrared image from Spitzer (red). While astronomers expected that dust particles were generating most
of the infrared emission, the study of this object indicates that much of the infrared is instead generated in heated gas.

The unique filamentary structure seen in the optical image by Hubble (white and yellow) has long set N49 apart from other supernova remnants, as most appear roughly circular in visible light. Recent mapping of molecular clouds suggests that this supernova remnant is expanding into a denser region to the southeast, which would cause its asymmetrical appearance. This idea is confirmed by the Chandra data. Although x-rays reveal a round shell of emission, the they also show brightening in the southeast, confirming the idea of colliding material in that area.

Image credit: NASA/CXC/STScI/JPL-Caltech/UIUC/Univ. of Minn.

Image of the Day Gallery NASA

Detailing the Big Picture
This image from NASA's Hubble Space Telescope shows the diverse collection of galaxies 450 million light-years away in cluster Abell S0740 near the constellation Centaurus.

The giant elliptical ESO 325-G004 looms large at the cluster's center. The galaxy, as massive as 100 billion of our suns, is home to thousands of globular clusters, small compact groups of hundreds of thousands of stars that are gravitationally bound systems.

Image of the Day Gallery "NASA". Water's Early Journey
NASA's Spitzer Space Telescope observed a fledgling solar system, like the one depicted in this artist's concept, and discovered deep within it enough water vapor to fill the oceans on Earth five times. This water vapor starts out in the form of ice in a cloudy cocoon (not pictured) that surrounds the embryonic star, called NGC 1333-IRAS 4B (buried in center of image). Material from the cocoon, including ice, falls toward the center of the cloud. The ice then smacks down onto a dusty pre-planetary disk circling the stellar

Imagen of the Day Gallery NASA Moving at Nearly the Speed of Light
Giant jets of subatomic particles moving at nearly the speed of light have been found coming from thousands of galaxies across the universe, but always from elliptical galaxies or galaxies in the process of merging -- until now. Using the combined power of the Hubble Space Telescope and other telescopes, astronomers have discovered a huge jet coming from a spiral galaxy similar to our own Milky Way.

Celestial Fireworks
Resembling the puffs of smoke and sparks from a summer fireworks display, this Hubble image depicts the delicate filaments debris from a stellar explosion in a neighboring galaxy.

Denoted N 49, or DEM L 190, this remnant is from a massive star that died in a supernova blast whose light would have reached Earth thousands of years ago. This filamentary material will eventually be recycled into building new
Image of the Day Gallery NASA

Another View
As smoke billows across Launch Pad 39A, Space Shuttle Endeavour climbs into the sky on mission STS-118, the 22nd shuttle flight to the International Space Station. The mission will continue space station construction by delivering a third starboard truss segment, S5, and other payloads such as the SPACEHAB module and the external stowage platform 3. The 11-day mission may be extended to as many as 14 depending on the test of the Station-to-Shuttle Power Transfer System that will allow
Image of the Day Gallery NASA

* Cosmologia *

*** Cosmologia ***
É o ramo da Astronomia que estuda a origem, estrutura
e evolução do Universo a partir da aplicação de métodos
Científicos. A Cosmologia muitas vezes é confundida com
a Astrofísica que é o ramo da Astronomia que estuda a
estrutura e as propriedades dos objetos Celestes e o
Universo como um todo através da Física Teórica.
A confusão ocorre porque ambas ciências sob alguns
aspectos seguem caminhos paralelos, e muitas vezes
considerados redundantes, embora não o sejam.
http://sites.google.com/site/cosmologiauniversal/

O estudo do Cosmos tem se acentuado
bastante mundialmente...