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Valentines Day Image from Eauropean Space Agency ESA

2013-02-15T23:42:00.001+05:30

PACIFIC Heart

From about 600 km high, the ESA’s Proba-1 satellite captured this image of a heart-shaped island in the Pacific Ocean.

Located about 20 km north of Bora Bora, Tupai is a coral island in French Polynesia.

With white-sand beaches and turquoise waters, this tropical paradise has become a romantic daytrip destination for couples.

The island has no permanent residents apart from the coconut plantation workers.

In this false-colour image, the land appears red and encircles a shallow lagoon. The line cutting through the land at the upper right is an airfield.

This image was acquired on 18 June 2008 by the CHRIS Compact High Resolution Imaging Spectrometer on Proba-1.

Credit : ESA

Find these beautiful valentines day images on the Earth

Satellites keep an eye on Dutch dikes

2012-10-24T12:19:00.004+05:30

This Landsat image from 6 September 2010 shows a small part of the intertidal Wadden Sea and two shallow, artificial lakes in the Netherlands. Visible in the image is the Afsluitdijk – a causeway that creates a division between the Wadden Sea to the north and the former Zuiderzee bay to the south.

After the dike was built, the Dutch were able to reclaim land from the sea – like the lighter coloured areas in the lower-central part of the image. Zooming in, we can see the patchwork of agricultural land plots.

ESA supports the Landsat series as a Third Party Mission, meaning it uses its ground infrastructure and expertise to acquire, process and distribute Landsat data to users.

Credits: USGS/ESA

Rocket Rollout

2012-10-24T12:14:00.002+05:30

The Soyuz rocket is rolled out to the launch pad by train, on Sunday, Oct. 21, 2012, at the Baikonur Cosmodrome in Kazakhstan. Launch of the Soyuz rocket is scheduled for Tuesday, Oct. 23. The rocket will send Expedition 33/34 Flight Engineer Kevin Ford of NASA, Soyuz Commander Oleg Novitskiy and Flight Engineer Engineer Evgeny Tarelkin of ROSCOSMOS on a five-month mission aboard the International Space Station.

Image Credit: NASA/Bill Ingalls

The Solar System’s grandest canyon

2012-10-24T12:11:00.002+05:30

Valles Marineris, seen at an angle of 45 degrees to the surface in near-true colour and with four times vertical exaggeration. The image covers an area of 630 000 sq km with a ground resolution of 100 m per pixel. The digital terrain model was created from 20 individual HRSC orbits, and the colour data were generated from 12 orbit swaths. The largest portion of the canyon, which spans right across the image, is known as Melas Chasma. Candor Chasma is the connecting trough immediately to the north, with the small trough Ophir Chasma beyond. Hebes Chasma can be seen in the far top left of the image.

The image was first published in 2009 in the ESA science monograph Mars Express: The Scientific Investigations.

Credits: ESA/DLR/FU Berlin (G. Neukum)

Sea Ice Off Eastern Greenland

2012-10-24T11:58:00.001+05:30

The MODIS instrument on NASA's Aqua satellite captured this visible image of Sea Ice off eastern Greenland on October 16, 2012.

Image Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team

Earth from Space: Kimberley

2012-10-24T11:53:00.006+05:30

Western Australia’s Kimberley region, with a coastline along the Timor Sea, is pictured in this Envisat image.

Off the coast in the lower left we can see a group of three coral reefs, known as the Rowley Shoals. Located on the edge of one of the world’s widest continental shelves, each atoll covers an area of 80–90 sq km including lagoons.

Near the centre of the image is King Sound – a large gulf measuring about 120 km long and 50 km wide. A handful of rivers empties into the sound such as the Fitzroy River, one of Australia’s largest watercourses. The port town of Derby lies near the mouth of this river.

King Sound has the highest tides in Australia, reaching a maximum range of over 11 m.
In the Great Sandy Desert to the south, average rainfall can exceed 300 mm. But the high evaporation rate makes up for the higher than normal desert rainfall.

In the lower-right corner we can see Lake Gregory. This inland drainage lake usually holds fresh water, but can become salty after a number of dry years. It is a major migratory area for shorebirds, and provides a breeding habitat for several species of water birds.

On the upper-right side is Australia’s largest artificial lake by volume, Lake Argyle, on the Ord River. The water is used for agriculture, and the lake is recognised as an important wetland area under the Ramsar Convention.

This image was acquired on 28 September 2010 by Envisat’s MERIS instrument.

Credits: ESA

Radioactive decay of titanium powers supernova remnant

2012-10-24T11:45:00.003+05:30

Supernova remnant SNR1987A is located 166 000 light-years away in the Large Magellanic Cloud. The light from the stellar explosion arrived at Earth in 1987, and has since provided astronomers with a natural laboratory to monitor how the brightness of a supernova changes over time.

Dominating this Hubble Space Telescope view of the remnant are two glowing loops and a very bright ring of shocked hotspots surrounding the location of the now-exploded central star. The material making up these loops and rings was probably ejected from the star earlier in its history and is now being illuminated by the supernova and its shockwave.

The titanium-44 detected by Integral is powering only the innermost part of the remnant.
Astronomers expect a neutron star to have been left after the explosion, but no definitive evidence for it has yet been found.
The field of view is about 25 x 25 arcseconds.

Credits: ESA/Hubble & NASA

Four Star Planet

2012-10-24T11:41:00.001+05:30

An artist's illustration of PH1, a planet discovered by volunteers from the Planet Hunters citizen science project. PH1, shown in the foreground, is the first reported case of a planet orbiting a double-star that, in turn, is orbited by a second distant pair of stars. The phenomenon is called a circumbinary planet in a four-star system.

A bit larger than Neptune and thought to be a gas giant, PH1 orbits its host stars every 137 days. Beyond the planet's orbit approximately 900 times the distance between the sun and Earth, a second pair of stars orbits the planetary system.

Image Credit: Haven Giguere/Yale

Earth from Space: Downtown Dubai

2012-10-24T11:28:00.003+05:30

This image from the Pleiades satellite shows part of Dubai in the United Arab Emirates.

Located south east of the Persian Gulf on the Arabian Peninsula, Dubai lies within the Arabian Desert. The city is a major business hub, and its revenues come from tourism, real estate and financial services. The light blue area near the centre of the image is the man-made Burj Khalifa Lake. Next to the lake sits a skyscraper that is the tallest man-made structure in the world. Its long shadow is cast to the north (to the right in this image).
Zooming in on the lake, we can see the curves and circles of the Dubai Fountain. The choreographed system shoots water 73 m into the air while accompanied by music.
The building, lake and fountain are part of a development called Downtown Dubai. Covering an area of 2 sq km, the mixed-use complex is estimated to cost US$20 billion.
Another notable structure of Downtown Dubai is the Dubai Mall, which appears as a vast grey structure in this image. It is the world’s largest shopping mall, and is also houses an aquarium and ice rink.
The large, dark area is where the saltwater Dubai Creek is being extended as part of the construction of the Business Bay development. The area is expected to have over 200 buildings for commercial and residential use.
In the upper left portion of the image, we can see Safa Park. It contains three lakes, over 200 species of birds and nearly 17 000 different types of vegetation.

The image was acquired by France’s Pleiades satellite on 4 January.

Credits: CNES 2012/Astrium Services/Spot Image

A Planetary Nebula Gallery

2012-10-20T11:44:00.002+05:30

This gallery shows four planetary nebulas from the first systematic survey of such objects in the solar neighborhood made with NASA's Chandra X-ray Observatory. The planetary nebulas shown here are NGC 6543, also known as the Cat's Eye, NGC 7662, NGC 7009 and NGC 6826. In each case, X-ray emission from Chandra is colored purple and optical emission from the Hubble Space Telescope is colored red, green and blue.

In the first part of this survey, published in a new paper, twenty one planetary nebulas within about 5000 light years of the Earth have been observed. The paper also includes studies of fourteen other planetary nebulas, within the same distance range, that Chandra had already observed.

A planetary nebula represents a phase of stellar evolution that the sun should experience several billion years from now. When a star like the sun uses up all of the hydrogen in its core, it expands into a red giant, with a radius that increases by tens to hundreds of times. In this phase, a star sheds most of its outer layers, eventually leaving behind a hot core that will soon contract to form a dense white dwarf star. A fast wind emanating from the hot core rams into the ejected atmosphere, pushes it outward, and creates the graceful, shell-like filamentary structures seen with optical telescopes.

The diffuse X-ray emission seen in about 30% of the planetary nebulas in the new Chandra survey, and all members of the gallery, is caused by shock waves as the fast wind collides with the ejected atmosphere. The new survey data reveal that the optical images of most planetary nebulas with diffuse X-ray emission display compact shells with sharp rims, surrounded by fainter halos. All of these compact shells have observed ages that are less than about 5000 years, which therefore likely represents the timescale for the strong shock waves to occur.

About half of the planetary nebulas in the study show X-ray point sources in the center, and all but one of these point sources show high energy X-rays that may be caused by a companion star, suggesting that a high frequency of central stars responsible for ejecting planetary nebulas have companions. Future studies should help clarify the role of double stars in determining the structure and evolution of planetary nebulas.

These results were published in the August 2012 issue of The Astronomical Journal. The first two authors are Joel Kastner and Rodolfo Montez Jr. of the Rochester Institute of Technology in New York, accompanied by 23 co-authors.

NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.

Credits: X-ray: NASA/CXC/RIT/J.Kastner et al.; Optical: NASA/STScI

Phobos in Transit

2012-09-23T14:56:00.003+05:30

Mars has two small, asteroid-sized moons named Phobos and Deimos. From the point of view of the rover, located near the equator of Mars, these moons occasionally pass in front of, or "transit," the disk of the sun. These transit events are the Martian equivalent of partial solar eclipses on Earth because the outline of the moons does not completely cover the sun (in contrast, Earth's moon does block the entire sun during a total solar eclipse). These eclipses, like those on Earth, occur in predictable "seasons" a few times each Mars year.

As part of a multi-mission campaign, NASA's Curiosity rover is observing these transits, the first of which involved the moon Phobos grazing the sun's disk. The event was observed on Martian day, or sol, 37 (September 13, 2012) using Curiosity's Mast Camera, or Mastcam, equipped with special filters for directly observing the sun. In a series of high-resolution video frames acquired at about three frames per second for about two minutes, the outline of part of Phobos blocked about five percent of the sun.

This animation shows the transit as viewed by the Mastcam 100-millimiter camera (M-100) in nine frames. Another version of the animation is available, consisting of 20 frames taken by the Mastcam 34-millimeter camera (M-34), which has about one-third the resolution of the M-100. In total, 256 frames were taken by the M-100 and 384 frames for the M-34.

› Mastcam-34 animation

The transit was also observed by Curiosity's Rover Environmental Monitoring Stations (REMS) instrument, which saw about a five percent drop in the sun's ultraviolet radiation during the event.

Mission scientists use these events to very accurately determine the orbital parameters of the Martian moons. Phobos, for example, orbits very close to Mars and is slowly spiraling in to Mars because of tidal forces. These forces change the orbital position of Phobos over time, and accurate measurements of those changes can provide information about the internal structure of that moon and how it dissipates energy. Deimos orbits much farther away and is slowly spiraling out.

NASA's Mars Exploration Rover Opportunity will also attempt to observe a different set of Phobos and Deimos transits, seen from the other side of the planet, in Meridiani Planum.

Image credit: NASA/JPL-Caltech/MSSS

Dunes in Noachis Terra Region of Mars

2012-09-23T14:49:00.002+05:30

This enhanced-color image shows sand dunes trapped in an impact crater in Noachis Terra, Mars. Dunes and sand ripples of various shapes and sizes display the natural beauty created by physical processes. The area covered in the image is about six-tenths of a mile (1 kilometer) across.

Sand dunes are among the most widespread wind-formed features on Mars. Their distribution and shapes are affected by changes in wind direction and wind strength. Patterns of dune erosion and deposition provide insight into the sedimentary history of the surrounding terrain.
The image is one product from an observation by the High Resolution Imaging Science Experiment (HiRISE) camera taken on Nov. 29, 2011, at 42 degrees south latitude, 42 degrees east longitude. Other image products from the same observation are at http://www.uahirise.org/ESP_025042_1375.

HiRISE is one of six instruments on NASA's Mars Reconnaissance Orbiter. The University of Arizona, Tucson, operates the orbiter's HiRISE camera, which was built by Ball Aerospace & Technologies Corp., Boulder, Colo. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter Project for the NASA Science Mission Directorate, Washington.

Image credit: NASA/JPL-Caltech/Univ. of Arizona

A Royal Celebration : Milky Way Galaxy

2012-09-23T14:46:00.000+05:30

This enormous section of the Milky Way galaxy is a mosaic of images from NASA's Wide-field Infrared Survey Explorer, or WISE. The constellations Cassiopeia and Cepheus are featured in this 1,000-square degree expanse. These constellations, named after an ancient Queen and King of Ethiopia in Greek mythology, are visible in the northern sky every night of the year as seen from most of the United States.

To the unaided human eye, Cassiopeia is easily recognizable by the five bright stars that make up its "W" shape. However, WISE observed infrared light, where the sky takes on a very different appearance. The bright stars of the constellations fade into obscurity amongst the backdrop of millions of other stars revealed by WISE. Cool clouds of dust that fill the space between the stars in the Milky Way glow in infrared light and tell us more about the story of how stars are born, and how they die.

Within this image are dozens of dense clouds, called nebulae. Many of the nebulae seen here are places where new stars are forming, creating bubble like structures that can be dozens to hundreds of light-years in size. The process of star formation within these giant clouds has been likened to fireworks, celebrating the birth of new generations of stars. But the death of stars is also seen in the remnants of a supernova explosion that was witnessed by the astronomer Tycho Brahe in 1572 AD. This remnant is located about one-fifth of the way from left of center, and about one-sixth of the way up from the middle of the image.

The colors used in this image represent specific wavelengths of infrared light. Blue and cyan (blue-green) represent light emitted at wavelengths of 3.4 and 4.6 microns, which is predominantly from stars. Green and red represent light from 12 and 22 microns, respectively, which is mostly emitted by dust. This image is a mosaic of thousands of individual frames from WISE, combined first into 442 interlocking tiles before re-projecting and stitching them into the final picture. This was done for each of the four WISE wavelengths, totaling nearly 30 billion pixels in the interlocking tiles.

JPL manages the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

More information is online at http://www.nasa.gov/wise and http://wise.astro.ucla.edu.

Image credit: NASA/JPL-Caltech/UCLA

Dusty Space Cloud

2012-09-23T14:37:00.004+05:30

This image shows the Large Magellanic Cloud galaxy in infrared light as seen by the Herschel Space Observatory, a European Space Agency-led mission with important NASA contributions, and NASA's Spitzer Space Telescope. In the instruments' combined data, this nearby dwarf galaxy looks like a fiery, circular explosion. Rather than fire, however, those ribbons are actually giant ripples of dust spanning tens or hundreds of light-years.

Significant fields of star formation are noticeable in the center, just left of center and at right. The brightest center-left region is called 30 Doradus, or the Tarantula Nebula, for its appearance in visible light.

The colors in this image indicate temperatures in the dust that permeates the Cloud. Colder regions show where star formation is at its earliest stages or is shut off, while warm expanses point to new stars heating surrounding dust. The coolest areas and objects appear in red, corresponding to infrared light taken up by Herschel's Spectral and Photometric Imaging Receiver at 250 microns, or millionths of a meter. Herschel's Photodetector Array Camera and Spectrometer fills out the mid-temperature bands, shown here in green, at 100 and 160 microns. The warmest spots appear in blue, courtesy of 24- and 70-micron data from Spitzer.

Herschel is a European Space Agency mission with significant NASA contributions. Launched in 2009, the spacecraft carries science instruments provided by consortia of European institutes. NASA's Herschel Project Office based at JPL contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the U.S. astronomical community. Caltech manages JPL for NASA.

Image credit: ESA/NASA/JPL-Caltech/STScI

Orion's Rainbow of Infrared Light

2012-09-23T14:32:00.003+05:30

This new view of the Orion nebula highlights fledgling stars hidden in the gas and clouds. It shows infrared observations taken by NASA's Spitzer Space Telescope and the European Space Agency's Herschel mission, in which NASA plays an important role.

A star forms as a clump of this gas and dust collapses, creating a warm glob of material fed by an encircling disk. These dusty envelopes glow brightest at longer wavelengths, appearing as red dots in this image. In several hundred thousand years, some of the forming stars will accrete enough material to trigger nuclear fusion at their cores and then blaze into stardom.

The nebula is found below the three belt stars in the famous constellation of Orion the Hunter, which appears at night in northern latitudes during fall and then throughout winter. At a distance of around 1,500 light-years away from Earth, the nebula cannot quite be seen with the naked eye. Binoculars or a small telescope, however, are all it takes to get a good look in visible light at this stellar factory.
Spitzer is designed to see shorter infrared wavelengths than Herschel. By combining their observations, astronomers get a more complete picture of star formation. The colors in this image relate to the different wavelengths of light, and to the temperature of material, mostly dust, in this region of Orion. Data from Spitzer show warmer objects in blue, with progressively cooler dust appearing green and red in the Herschel datasets. The more evolved, hotter embryonic stars thus appear in blue.

The combined data traces the interplay of the bright, young stars with the cold and dusty surrounding clouds. A red garland of cool gas also notably runs through the Trapezium, the intensely bright region that is home to four humungous blue-white stars, and up into the rich star field.

Infrared data at wavelengths of 8.0 and 24 microns from Spitzer are rendered in blue. Herschel data with wavelengths of 70 and 160 microns are represented in green and red, respectively.

Herschel is a European Space Agency cornerstone mission, with science instruments provided by consortia of European institutes and with important participation by NASA. NASA's Herschel Project Office is based at NASA's Jet Propulsion Laboratory. JPL contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the United States astronomical community. Caltech manages JPL for NASA.

Credit : NASA/ESA/JPL-Caltech/IRAM

Soyuz TMA-04M Capsule

2012-09-23T12:35:00.002+05:30

201209170012hq (17 Sept. 2012) --- Russian support personnel are seen as they access the crew of the Soyuz TMA-04M capsule shortly after it landed with

Joe Acaba Resting near Soyuz Capsule after landing

Gennedy padalka Resting near Soyuz Capsule after landing

Sergei Revin Resting near Soyuz Capsule after landing

Expedition 32 Commander Gennady Padalka of Russia, NASA Flight Engineer Joe Acaba and Russian Flight Engineer Sergei Revin in a remote area near the town of Arkalyk, Kazakhstan, on Sept. 17, 2012 (Kazakhstan time). Padalka, Acaba and Revin returned from five months onboard the International Space Station where they served as members of the Expedition 31 and 32 crews.

Photo credit: NASA/Carla Cioffi

Soyuz TMA-04M Spacecraft departs from the International Space Station

2012-09-23T12:25:00.002+05:30

ISS033-E-005112 (16 Sept. 2012) --- The Soyuz TMA-04M spacecraft departs from the International Space Station and heads toward a landing in a remote area outside of the town of Arkalyk, Kazakhstan, on Sept. 17, 2012 (Kazakhstan time). Expedition 32 Commander Gennady Padalka of Russia, NASA Flight Engineer Joe Acaba and Russian Flight Engineer Sergei Revin are returning from five months onboard the International Space Station where they served as members of the Expedition 31 and 32 crews.

Credit : NASA

James Webb Space Telescope Mirror 'Cans'

2012-09-23T12:14:00.003+05:30

The powerful primary mirrors of the James Webb Space Telescope will be able to detect the light from distant galaxies.

The manufacturer of those mirrors, Ball Aerospace & Technologies Corp. of Boulder, Colo., recently celebrated their successful efforts as mirror segments were packed up in special shipping canisters (cans) for shipping to NASA.

The Webb telescope has 21 mirrors, with 18 primary mirror segments working together as one large 21.3-foot (6.5-meter) primary mirror. The mirror segments are made of beryllium, which was selected for its stiffness, light weight and stability at cryogenic temperatures.

Bare beryllium is not very reflective of near-infrared light, so each mirror is coated with about 0.12 ounce of gold.

Image Credit: Ball Aerospace

Expedition 32 Soyuz TMA-04M Spacecraft Landing

2012-09-23T12:10:00.002+05:30

The Soyuz TMA-04M spacecraft is seen as it lands with Expedition 32 Commander Gennady Padalka of Russia, NASA Flight Engineer Joe Acaba and Russian Flight Engineer Sergie Revin in a remote area near the town of Arkalyk, Kazakhstan, on Monday, September 17, 2012. Padalka, Acaba and Revin returned from five months onboard the International Space Station where they served as members of the Expedition 31 and 32 crews.

Photo Credit: NASA/Carla Cioffi

Endeavour's Final Flight Ends : Los Angeles

2012-09-23T11:59:00.005+05:30

The space shuttle Endeavour, atop the Shuttle Carrier Aircraft, or SCA, lands at Los Angeles International Airport on Tuesday, Sept. 21, 2012 in Los Angeles where it will be placed on public display at the California Science Center. Today's flight marks the final scheduled ferry flight of the Space Shuttle Program.

Photo Credit: (NASA/Matt Hedges)

Full View of Vesta

2012-09-23T11:56:00.001+05:30

As NASA's Dawn spacecraft takes off for its next destination, this mosaic synthesizes some of the best views the spacecraft had of the giant asteroid Vesta. Dawn studied Vesta from July 2011 to September 2012.

The towering mountain at the south pole — more than twice the height of Mount Everest — is visible at the bottom of the image. The set of three craters known as the "snowman" can be seen at the top left.

These images are the last in Dawn's Image of the Day series during the cruise to Dawn's second destination, Ceres. A full set of Dawn data is being archived at http://pds.nasa.gov/ .

The Dawn mission to Vesta and Ceres is managed by NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, for NASA's Science Mission Directorate, Washington D.C. UCLA is responsible for overall Dawn mission science. The Dawn framing cameras were developed and built under the leadership of the Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany, with significant contributions by DLR German Aerospace Center, Institute of Planetary Research, Berlin, and in coordination with the Institute of Computer and Communication Network Engineering, Braunschweig. The Framing Camera project is funded by the Max Planck Society, DLR, and NASA/JPL.

Image credit: NASA/JPL-Caltech/UCAL/MPS/DLR/IDA

Wildland Fires in Idaho

2012-09-23T11:50:00.004+05:30

ISS033-E-005644 (19 Sept. 2012) --- One of the Expedition 33 crew members aboard the International Space Station, flying at an altitude of approximately 260 statute miles, recorded this nadir scene of the Mustang Complex wildland fires in Idaho. Close to 300,000 acres have been burned by the Mustang fires and hundreds of people have been forced to flee the area.

Credit : Expedition 33 crew / International Space Station / NASA

Tropical Storm Jelawat (Pacific Ocean) : NASA Satellite Sees Tropical Storm Jelawat Form in Northwestern Pacific

2012-09-23T11:46:00.003+05:30

As another tropical storm was forming in the northwestern Pacific Ocean, NASA's Terra satellite was providing forecasters at the Joint Typhoon Warning Center with visible and other data on the storm.

NASA's Terra satellite passed over Tropical Depression 18W before it strengthened into Tropical Storm Jelawat late in the day on Sept. 20, in the Philippine Sea (part of the western North Pacific Ocean basin).

On Sept. 20 at 01:50 UTC, as the depression was strengthening into a tropical storm, the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on NASA's Terra satellite captured a true-color image of the storm. The MODIS image showed a rounded shape, which indicates good circulation. There was also a band of thunderstorms east of the center of circulation.

On Sept. 21, Tropical Storm Jelawat had maximum sustained winds near 45 knots (51.7 mph/83.3 kph). Jelawat was located about 535 nautical miles east-southeast of Manila, Philippines, near 12.4 north latitude and 129.7 east longitude. It was moving to the west-southwest at 7 knots (8 mph/13 kph).

Forecasters used infrared satellite imagery, such as that from the Atmospheric Infrared Sounder instrument that flies aboard NASA's Aqua satellite to determine the initial position of the tropical storm. Infrared data from Sept. 21, 2012, showed that the strongest convection and coldest cloud top temperatures were in the northwestern and southeastern quadrants of the tropical storm. Those areas were experiencing the heaviest rainfall.

By 10 p.m. local time in Manila, Philippines (10 a.m. Eastern Time/U.S.) on Sept. 21, Jelawat's center was about 311 miles (500 km) east of Catarman capital of Northern Samar, near 12.4 north latitude and 129.7 east longitude. Northern Samar is a Philippine province in the Eastern Visayas region.

The Philippine Atmospheric Geophysical and Astronomical Services Administration issued a bulletin about Jelawat (known locally as Lawin) on Sept. 21 that noted "Estimated rainfall amount is from 10 to 25 mm (0.4 to 0.9 inches) per hour within the 600 km (373 miles) diameter of the Tropical Storm. Fishing boats and other small seacrafts are advised not to venture out into the eastern seaboard of Southern Luzon, Visayas and Mindanao due to big waves generated by Tropical Storm (Jelawat) Lawin."

Jelawat is expected to track slowly west-northwestward over the weekend of Sept. 22 and 23 while the storm intensifies. The forecast track from the Joint Typhoon Warning Center keeps the center of Jelawat at sea, while almost tracking parallel to the Philippines.

Credit: NASA/Goddard/MODIS Rapid Response Team

Black Sea : Earth From Space

2012-09-23T11:40:00.003+05:30

The southern Ukrainian coast along the Black Sea was captured in this image acquired on 1 May 2011 by the SPOT-5 satellite.

The green and yellow patchwork of agricultural dominates the land, while blue swirls of sediment and phytoplankton are present along parts of the coast.

The Black Sea, bordered by Romania, Bulgaria, Turkey, Russia, Georgia and Ukraine, is almost cut off completely from the rest of the world’s other oceans, yet it reaches depths of over 2000 m.

The straits of Bosporus and Dardanelle connect the Black Sea to the Mediterranean Sea.

Credits: CNES/Spot Image/ESA

Kepler supernova remnant

2012-09-16T21:15:00.001+05:30

In 1604, a new star appeared in the night sky that was much brighter than Jupiter and dimmed over several weeks. This event was witnessed by sky watchers including the famous astronomer Johannes Kepler. Centuries later, the debris from this exploded star is known as the Kepler supernova remnant.

Astronomers have long studied the Kepler supernova remnant and tried to determine exactly what happened when the star exploded to create it. New analysis of a long observation from NASA’s Chandra X-ray Observatory is providing more clues. This analysis suggests that the supernova explosion was not only more powerful, but might have also occurred at a greater distance, than previously thought.

This image shows the Chandra data derived from more than eight days worth of observing time. The X-rays are shown in five colors from lower to higher energies: red, yellow, green, blue, and purple. These various X-ray slices were then combined with an optical image from the Digitized Sky Survey, showing stars in the field.

Previous analysis of this Chandra image has determined that the stellar explosion that created Kepler was what astronomers call a “Type Ia” supernova. This class of supernovas occurs when a white dwarf gains mass, either by pulling gas off a companion star or merging with another white dwarf, until it becomes unstable and is destroyed by a thermonuclear explosion.

Unlike other well-known Type Ia supernovas and their remnants, Kepler’s debris field is being strongly shaped by what it is running into. More specifically, most Type Ia supernova remnants are very symmetrical, but the Kepler remnant is asymmetrical with a bright arc of X-ray emission in its northern region. This indicates the expanding ball of debris from the supernova explosion is plowing into the gas and dust around the now-dead star.

The bright X-ray arc can be explained in two ways. In one model, the pre-supernova star and its companion were moving through the interstellar gas and losing mass at a significant rate via a wind, creating a bow shock wave similar to that of a boat moving through water. Another possibility is that the X-ray arc is caused by debris from the supernova expanding into an interstellar cloud of gradually increasing density.

The wind and bow shock model described above requires that the Kepler supernova remnant is located at a distance of more than 23,000 light years. In the latter alternative, the gas into which the remnant is expanding has higher density than average, and the distance of the remnant from the earth is between about 16,000 and 20,000 light years. Both alternatives give greater distances than the commonly used value of 13,000 light years.

In either model, the X-ray spectrum -- that is, the amount of X-rays produced at different energies -- reveals the presence of a large amount of iron, and indicates an explosion more energetic than the average Type Ia supernova. Additionally, to explain the observed X-ray spectrum in this model, a small cavity must have been cleared out around the star before it exploded. Such a cavity, which would have a diameter less than a tenth that of the remnant’s current size, might have been produced by a fast, dense outflow from the surface of the white dwarf before it exploded, as predicted by some models of Type Ia supernovas.

Evidence for an unusually powerful Type Ia supernova has previously been observed in another remnant with Chandra and an optical telescope. These results were independently verified by subsequent observations of light from the original supernova explosion that bounced off gas clouds, a phenomenon called light echoes. This other remnant is located in the Large Magellanic Cloud, a small galaxy about 160,000 light years from Earth, making it much farther away than Kepler and therefore more difficult to study.

These results were published in the September 1st, 2012 edition of The Astrophysical Journal. The authors of this study are Daniel Patnaude from the Smithsonian Astrophysical Observatory in Cambridge, MA; Carles Badenes from University of Pittsburgh in Pittsburgh, PA; Sangwook Park from the University of Texas at Arlington, TX, and Martin Laming from the Naval Research Laboratory in Washington DC.

NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.

Credits: X-ray: NASA/CXC/SAO/D.Patnaude, Optical: DSS