The Ghost Head Nebula

NGC 2080. Credit: Mohammad Heydari-Malayeri (Observatoire de Paris) et al

This image from NASA's Hubble Space Telescope reveals a vibrant green and red nebula far from Earth, where nature seems to have put on the traditional colours of the season. These colours, produced by the light emitted by oxygen and hydrogen, help astronomers investigate the star-forming processes in nebulas such as NGC 2080.

The light from the nebula captured in this image is emitted by two elements, hydrogen and oxygen. The red and the blue light are from regions of hydrogen gas heated by nearby stars. The green light on the left comes from glowing oxygen. The energy to illuminate the green light is supplied by a powerful stellar wind (a stream of high-speed particles) coming from a massive star just outside the image.

The white region in the center is a combination of all three emissions and indicates a core of hot, massive stars in this star-formation region. The intense emission from these stars has carved a bowl-shaped cavity in the surrounding gas.

In the white region, the two bright areas (the "eyes of the ghost") - named A1 (left) and A2 (right) - are very hot, glowing "blobs" of hydrogen and oxygen. The bubble in A1 is produced by the hot, intense radiation and powerful stellar wind from a single massive star. A2 has a more complex appearance due to the presence of more dust, and it contains several hidden, massive stars. The massive stars in A1 and A2 must have formed within the last 10,000 years, since their natal gas shrouds are not yet disrupted by the powerful radiation of the newly born stars.

This "enhanced colour" picture spanning 55 light years in the above image is composed of three narrow-band-filter images obtained with Hubble's Wide Field Planetary Camera 2. The colours are red (ionized hydrogen, H-alpha, 1040 seconds), green (ionized oxygen, 1200 seconds) and blue (ionized hydrogen, H-beta, 1040 seconds).

The Ghost Head Nebula NGC 2080 is a star forming region in the Large Magellanic Cloud, a satellite galaxy of our own Milky Way.

Halloween's ancient & astronomical origins date back to the ancient Celtic festival of Samhain (pronounced sow-in).
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The Celts, who lived 2,000 years ago in the area that is now Ireland, the United Kingdom, and northern France, celebrated their new year on November 1. This day marked the end of summer and the harvest and the beginning of the dark, cold winter, a time of year that was often associated with human death. Celts believed that on the night before the new year, the boundary between the worlds of the living and the dead became blurred. On the night of October 31, they celebrated Samhain, when it was believed that the ghosts of the dead returned to earth. In addition to causing trouble and damaging crops, Celts thought that the presence of the otherworldly spirits made it easier for the Druids, or Celtic priests, to make predictions about the future. For a people entirely dependent on the volatile natural world, these prophecies were an important source of comfort and direction during the long, dark winter.

To commemorate the event, Druids built huge sacred bonfires, where the people gathered to burn crops and animals as sacrifices to the Celtic deities.

During the celebration, the Celts wore costumes, typically consisting of animal heads and skins, and attempted to tell each other's fortunes. When the celebration was over, they re-lit their hearth fires, which they had extinguished earlier that evening, from the sacred bonfire to help protect them during the coming winter.

By A.D. 43, Romans had conquered the majority of Celtic territory. In the course of the four hundred years that they ruled the Celtic lands, two festivals of Roman origin were combined with the traditional Celtic celebration of Samhain.

The first was Feralia, a day in late October when the Romans traditionally commemorated the passing of the dead. The second was a day to honor Pomona, the Roman goddess of fruit and trees. The symbol of Pomona is the apple and the incorporation of this celebration into Samhain probably explains the tradition of "bobbing" for apples that is practiced today on Halloween.

By the 800s, the influence of Christianity had spread into Celtic lands. In the seventh century, Pope Boniface IV designated November 1 All Saints' Day, a time to honor saints and martyrs. It is widely believed today that the pope was attempting to replace the Celtic festival of the dead with a related, but church-sanctioned holiday. The celebration was also called All-hallows or All-hallowmas (from Middle English Alholowmesse meaning All Saints' Day) and the night before it, the night of Samhain, began to be called All-hallows Eve and, eventually, Halloween. Even later, in A.D. 1000, the church would make November 2 All Souls' Day, a day to honor the dead. It was celebrated similarly to Samhain, with big bonfires, parades, and dressing up in costumes as saints, angels, and devils. Together, the three celebrations, the eve of All Saints', All Saints', and All Souls', were called Hallowmas.

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Seeing Colour in Nebulae from A Quantum Diaries Survivor
Celestial Mandrill Is A Cosmic Ghost from Scientific Blogging
Astronomers simulate life & death in the Universe from Science Daily
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Future Space Craft

The risks from radiation in space, and the need to keep the crew safe on long flights, may influence the shape of future spaceships.

The major radiation sources are galactic cosmic rays, charged particles: from electrons up to the heavy metal elements and 'solar particle events', which throw out protons and helium nuclei.

Exposure from the hazards of severe space radiation in long-duration deep space missions is 'the show stopper'. Protection from the hazards of severe space radiation is of paramount importance to NASA's new vision to reach the Moon, Mars and beyond.

The electrons, protons & heavy-metal ions such as iron and uranium whiz through the void and can all cause cancers. But aluminium shielding capable of staving the radiation off on extended journeys would be prohibitively heavy, burning too much fuel.

The ideal form, according to Ram Tripathi, a spaceflight engineer at NASA, is a grapefruit spiked with cherries on sticks. With positively and negatively charged metal spheres be arranged on struts jutting out of the crew capsule, in carefully controlled directions, to give the crew a high degree of electrostatic radiation cover.

Tripathi calculates the "cherries" would need to be between 10 and 20 metres in diameter and would be stationed about 50 metres from the crew capsule – the "grapefruit". These spheres would protect the crew by deflecting charged particles away from the central habitat. Spheres give you more volume and less mass, and evenly distribute the deflecting charges over their surface.

The charged spheres would be made of lightweight hollow aluminium, the material shielding the crew capsule would incorporate carbon nanotubes – in a novel composite with aluminium. The nanotubes are light, they can take a pounding from heavy incoming ions.

Or we could have spaceships with a more conventional shape like a submarine, the starship enterprise, the space shuttle or nerva, with a false skin filled with smaller spheres (or even tubes) having the same desired effect, deflecting radiation and adding volume, without overwhelmingly increasing the mass.


Laser power stations, drawing energy from the local environment, might one day propel spacecraft throughout the solar system. NASA studies of advanced planetary missions have ranged from small robotic probes to multiple-spacecraft human exploration missions.
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The completed International Space Station will have a mass of about 1,040,000 pounds. It will measure 356 feet across and 290 feet in length, with almost an acre of solar panels to provide electrical power to six laboratories.

The assembled space station will provide the first laboratory complex where gravity, a fundamental force on Earth, can be controlled for extended periods. This control of gravity opens up an unimaginable world where almost everything grows differently than on Earth. For example, purer protein crystals can be grown in space than on Earth. By analyzing crystals grown on the ISS, scientists may be able to develop medicines that target particular disease-causing proteins.

Such crystals for research into cancer, diabetes, emphysema and immune disorders grown on the space station have already shown promise. New drugs to fight influenza and post-surgery inflammation are already in clinical trials, and future research will benefit from the extended exposure to weightlessness available on the station.

Many of the changes in the human body that result from space flight mimic those seen on Earth as a result of aging. Understanding of the causes of these changes may lead to the development of countermeasures against bone loss, muscle atrophy, balance disorders and other symptoms common in an aging population.

The Johnson Space Centre, together with scientists and researchers at NASA's other field centers, is working on the technologies that will be required for further exploration of the universe in the next years. For example, a new rocket team at Marshall is developing revolutionary technologies that will make space transportation as safe, reliable and affordable as today's airline transportation.

Hospitals, business parks and solar electric power stations that beam clean, inexpensive energy back to Earth are likely to dot the "space-scape" 40 years from now. Space adventure tourism and travel, orbiting movie studios, and worldwide, two-hour express package delivery also appear just over the horizon.

By 2040, it's expected to cost only tens of dollars per pound to launch humans or cargo to space; today, it costs as much as $10,000 per pound. Bridging that gap requires intense research and technology development focused on accelerating breakthroughs that will serve as keys to open the space frontier for business and pleasure.

Space transportation technology breakthroughs will launch a new age of space exploration, just as the silicon chip revolutionized the computer industry and made desktop computers commonplace.

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The New Space Race by Brian Appleyard @ The Sunday Times
The first Sino-European Satellite completes four year mission ESA
The Johnson Space Centre Celebrates 40 Years of Human Space Flight
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Beta Pictoris

NASA's Hubble Space Telescope revealed two dust disks circling the nearby star Beta Pictoris. The images confirm a decade of scientific speculation that a warp in the young star's dust disk may actually be a second inclined disk, which is evidence for the possibility of a planet that is at least as big as Neptune. Credit: NASA

Puffy debris disks around three nearby stars could harbour Pluto-sized planets-to-be, a new computer model suggests.

The "planet embryos" are predicted to orbit three young, nearby stars, located within about 60 light years or less of our solar system. Beta Pictoris & AU Microscopii are both about 12 million years old, while a third star, Fomalhaut, is aged at 200 million years old.


If confirmed, the objects would represent the first evidence of a never-before-observed stage of early planet formation. Another team recently spotted "space lint" around a nearby star that pointed to an even earlier phase of planet building, when baseball-sized clumps of interstellar dust grains are colliding together.

The thickness of a dust ring or debris disk depends on the size of objects orbiting inside it. The ring of dust thins as the star system ages, but if enough dust has clumped together to form an embryonic planet, it knocks the other dust grains into eccentric orbits. Over time, this can puff up what was a razor-thin disk.

The new finding will be detailed in an upcoming issue of the Monthly Notices of the Royal Astronomical Society.
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Solar Storm rips tail of Comet - from NASA. See short movie
Circumstellar Debris Disks resemble our Kuiper Belt from Hubble
Dawn's early light, Ceres & Vesta by Amara @ Scientific Blogging
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Planetary Nebulae

Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA) STScI-PRC07-33a

The colourful, intricate shapes in these NASA Hubble Space Telescope images reveal how the glowing gas ejected by dying Sun-like stars evolves dramatically over time.

These gaseous clouds, called planetary nebulae, are created when stars in the last stages of life cast off their outer layers of material into space. Ultraviolet light from the remnant star makes the material glow. Planetary nebulae last for only 10,000 years, a fleeting episode in the 10-billion-year lifespan of Sun-like stars.

The name planetary nebula has nothing to do with planets. They got their name because their round shapes resembled planets when seen through the small telescopes of the eighteenth century.

The Hubble images show the evolution of planetary nebulae, revealing how they expand in size and change temperature over time. A young planetary nebula, such as He 2-47, is small and dominated by relatively cool, glowing nitrogen gas. In the Hubble images, the red, green, and blue colours represent light emitted by nitrogen, hydrogen, and oxygen, respectively.

Over thousands of years, the clouds of gas expand away and the nebulae become larger. Energetic ultraviolet light from the star penetrates more deeply into the gas, causing the hydrogen and oxygen to glow more prominently, as seen near the center of NGC 5315. In the older nebulae, such as IC 4593, at bottom, left, and NGC 5307, at bottom, right, hydrogen and oxygen appear more extended in these regions, and red knots of nitrogen are still visible.
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These four nebulae all lie in our Milky Way Galaxy. Their distances from Earth are all roughly the same, about 7,000 light-years. The snapshots were taken with Hubble's Wide Field Planetary Camera 2 in February 2007. Like snowflakes, planetary nebulae show a wide variety of shapes, indicative of the complex processes that occur at the end of stellar life.

He 2-47, is dubbed the "starfish" because of its shape. The six lobes of gas and dust, which resemble the legs of a starfish, suggest that He 2-47 puffed off material at least three times in three different directions. Each time, the star fired off a narrow pair of opposite jets of gas. He 2-47 is in the southern constellation Carina.

NGC 5315, the chaotic-looking nebula at top, reveals an x-shaped structure. This shape suggests that the star ejected material in two different outbursts in two distinct directions. Each outburst unleashed a pair of diametrically opposed outflows. NGC 5315 lies in the southern constellation Circinus.

IC 4593, is in the northern constellation Hercules. NGC 5307, displays a spiral pattern, which may have been caused by the dying star wobbling as it expelled jets of gas in different directions. NGC 5307 resides in the southern constellation Centaurus.

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A Grand Vision for European Astronomy from ESO
A New Reduction of the Hipparcos Catalogues from ESA
Mysterious radio signal from deep space @ Cosmos Magazine
Mysterious Energy Burst Stuns Astronomers from Science Daily
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Feasting Blackhole bubbles

These NASA Hubble Space Telescope images of the galaxy's central region clearly show one of the bubbles rising from a dark band of dust. The other bubble, emanating from below the dust band, is barely visible, appearing as dim red blobs in the close-up picture of the galaxy's hub (the colourful picture at right).

The background image represents a wider view of the galaxy, with the central region defined by the white box.

These extremely hot bubbles are caused by the black hole's voracious eating habits. The eating machine is engorging itself with a banquet of material swirling around it in an accretion disk (the white region below the bright bubble). Some of this material is spewed from the disk in opposite directions. Acting like high-powered garden hoses, these twin jets of matter sweep out material in their paths.

The jets eventually slam into a wall of dense, slow-moving gas, which is traveling at less than 223,000 mph (360,000 kph). The collision produces the glowing material. The bubbles will continue to expand and will eventually dissipate.

Credits: NASA and Jeffrey Kenney (Yale University)
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Journey to the Black Hole from Space dotcom
Black Holes and Naked Singularities from Science Daily
Searching for Objects Even Stranger Than Black Holes from Universe Today
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Teardrop in the Sky

A spinning star found feeding on its stellar companion, whittling it down to an object smaller than some planets. Pulsars are the cores of burnt out "neutron" stars that spin hundreds of times per second.

The object’s minimum mass is only about 7 times the mass of Jupiter. But instead of orbiting a normal star, this low-mass body orbits a rapidly spinning pulsar every 54.7 minutes, at an average distance of only about 230,000 miles (slightly less than the Earth-Moon distance).

"This object is merely the skeleton of a star," says study team member Craig Markwardt of NASA's Goddard Space Flight Center in Maryland. "The pulsar has eaten away the star's outer envelope, and all that remains is its helium-rich core."

The system was discovered in early June when NASA's Swift and Rossi X-ray Timing Explorer (RXTE) satellites picked up an outburst of X-rays and gamma rays in the direction of the Milky Way galactic center in the constellation Sagittarius, and named SWIFT J1756.9-2508.
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Scientists think that several billion years ago, the system consisted of a very massive star and a smaller star about 1 to 3 times the mass of our sun. The bigger star evolved quickly and exploded as a supernova, leaving behind a spinning stellar corpse known as a neutron star. Meanwhile, the smaller star began to evolve as well, eventually puffing up into a red giant whose outer envelope encapsulated the neutron star.

This caused the two stars to draw closer together, while simultaneously ejecting the red giant's envelope into space.

After billions of years, little remains of the companion star, and it's uncertain whether it will survive. "It's been taking a beating, but that's part of nature," said study team member Hans Krimm, also of NASA Goddard.

Today, the two objects are so close to each other that the neutron star's powerful gravity siphons gas from its companion to form a spinning disk around itself. The disk occasionally dumps large quantities of gas onto the neutron star, creating an outburst like the one detected in June.

Image Credit: Aurore Simonnet/Sonoma State University

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Hubble Captures Stars Going Out in Style
Planet Survives Star's Death Throes from LiveScience
The Universe through the looking glass from NASA Science
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Exploding Lunar Eclipse

Most of us appreciate lunar eclipses for their silent midnight beauty. NASA astronomer Bill Cooke is different: he loves the explosions.
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On Tuesday morning, Aug. 28th, Earth's shadow settled across the Moon for a 90-minute total eclipse: full story. In the midst of the lunar darkness, Cooke tries to record flashes of light - explosions caused by meteoroids crashing into the Moon and blasting themselves to smithereens.

Lunar explosions are nothing new. Cooke's team has been monitoring the Moon since late 2005 and they've recorded 62 impacts so far. "Meteoroids that hit Earth disintegrate in the atmosphere, producing a harmless streak of light. But the Moon has no atmosphere, so 'lunar meteors' plunge into the ground," he says. Typical strikes release as much energy as 100 kg of TNT, gouging craters several meters wide and producing bursts of light bright enough to be seen 240,000 miles away on Earth through ordinary backyard telescopes.

"About half of the impacts we see come from regular meteor showers like the Perseids and Leonids," said team-member Danielle Moser. "The other half are 'sporadic' meteors associated with no particular asteroid or comet."

Read more on "Exploding Eclipse" from NASA

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Quad Galaxy Collision

One of the biggest galaxy collisions ever observed is taking place at the centre of this image from Spitzer.
The four white blobs in the middle are large galaxies that have begun to tangle and ultimately merge into a single gargantuan galaxy.


The whitish cloud around the colliding galaxies contains billions of stars tossed out during the messy encounter. Other galaxies and stars appear in yellow, orange and red hues. Blue shows hot gas that permeates this distant region of tightly packed galaxies.

NASA's Spitzer Space Telescope serendipitously spotted the quadruple merger during a routine survey of a distant galaxy cluster, called CL0958+4702, located nearly 5 billion light years away.

Spitzer's infrared eyes observed an unusually large fan-shaped plume of light emerging from a gathering of four elliptical galaxies. Three of the galaxies are about the size of the Milky Way, while the fourth is three times as large.
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The plume turned out to be billions of elderly stars ejected and abandoned during the clash. About half of the stars in the plume will later fall back into the galaxies.

Spitzer observations also show that, unlike most known mergers, the galaxies involved in the quadruple collision are bereft of gas, the source material that fuels star birth. As a result, astronomers predict relatively few new stars will be born in the new, combined galaxy.


Artist's concept showing what the night sky might look like from a hypothetical planet around a star tossed out of an ongoing four-way collision between big galaxies.

Credit: NASA/JPL-Caltech/Harvard-Smithsonian CfA

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Galactic Collisions Set Quasars Ablaze from Universe Today
Astronomers Spot Brightest Galaxies in the Distant Universe CfA
First Light for World's Largest 'Thermometer Camera' ESO release
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NASA's Endeavour launch

National Aeronautics and Space Administration announced the launch countdown schedule for space shuttle Endeavour.

NASA delays launch of Endeavour by 24 hours because of unexpected work to resolve an air leak in the crew cabin. Engineers installed a replacement valve taken from the space shuttle Atlantis. Lift off is now set for the evening of Wednesday 8th August.
The launch window lasts 5 minutes.

During the 11-day mission to the ISS International Space Station, Endeavour's crew will add another truss segment to the expanding station, install a gyroscope and add an external spare parts platform.

The flight will also include at least three spacewalks and will debut a new system that enables docked shuttles to draw electrical power from the station to extend visits to the outpost. If the system functions as expected, three days will be added to the mission.

The STS-118 mission is the 119th space shuttle flight, the 20th flight for Endeavour and the 22nd U.S. flight to the ISS. The mission would be Endeavour's first flight in more than four years.
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Space Shuttle Endeavour's Cargo from Space Com
Nuclear fusion could power NASA spacecraft in two decades from Goldenship
The European Space Agency's DARWIN proposals online from Centauri Dreams
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Uncovering the Veil Nebula

The Veil Nebula from Vimeo. Click on arrows for full screen view.

When a star significantly heavier than our Sun runs out of fuel, it collapses and blows itself apart in a catastrophic supernova explosion. A supernova releases so much light that it can outshine a whole galaxy of stars put together.

The exploding star sweeps out a huge bubble in its surroundings, fringed with actual stellar debris along with material swept up by the blast wave. This glowing, brightly-coloured shell of gas forms a nebula: a supernova remnant. Such a remnant can remain visible long after the initial explosion fades away.

Scientists estimate that the supernova explosion occurred some 5000 to 10 000 years ago and could have been witnessed and recorded by ancient civilizations. These would have seen a star increase in brightness to roughly the brightness of the crescent Moon.
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A series of three new images taken with the NASA/ESA Hubble Space Telescope reveals magnificent sections of one of the most spectacular supernova remnants in the sky - the Veil Nebula. The entire shell spans about 3 degrees, corresponding to about 6 full Moons. The small regions captured in the new Hubble images provide stunning close-ups of the Veil. Fascinating smoke-like wisps of gas are all that remain visible of what was once a Milky Way star.



The intertwined rope-like filaments of gas in the Veil Nebula result from the enormous amounts of energy released as the fast-moving debris from the explosion ploughs into its surroundings and creates shock fronts. These shocks, driven by debris moving at 600 000 kilometres per hour, heat the gas to millions of degrees. It is the subsequent cooling of this material that produces the brilliantly coloured glows.

Like the larger scale ground-based observations, the high-resolution Hubble images display two characteristic features: sharp filaments and diffuse emission. These correspond to two different viewing geometries: sharp filaments correspond to an edge-on view of a shock front, and diffuse emission corresponds to a face-on view.



The Hubble images of the Veil Nebula are striking examples of how processes that take place hundreds of lightyears away can sometimes resemble effects we see around us in our daily life. The structures have similarities to the patterns formed by the interplay of light and shadow on the bottom of a swimming pool, rising smoke or ragged cirrus clouds.



Supernovae are extremely important for understanding our own Milky Way. Although only a few stars per century in our Galaxy will end their lives in this spectacular way, these explosions are responsible for making all chemical elements heavier than iron in the Universe. Many elements, such as copper, mercury, gold, iodine and lead that we see around us here on Earth today were forged in these violent events thousands of millions of years ago.
The expanding shells of supernova remnants were mixed with other material in the Milky Way and became the raw material for new generations of stars and planets.

The chemical elements that constitute the Earth, the planets and animals we see around us - and as a matter of fact our very selves - were built deep inside ancient stars and in the supernova explosions that result in the nebula we are seeing here. The green in the grass and the red of our blood are indeed the colours of stardust.

Also known as Cygnus Loop, the Veil Nebula is in the constellation of Cygnus, the Swan, about 1500 lightyears away from Earth.

Wide-field ground-based photo of the Veil Nebula
Image credit & copyright: NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration. Acknowledgment: J. Hester (Arizona State University)

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LISA - Beyond Einstein

The Beyond Einstein Program consists of five proposed missions:

two major observatories and three smaller probes. Technology development already is under way on the proposed observatories. The Laser Interferometer Space Antenna (LISA) would orbit the sun and measure gravitational waves in our galaxy and beyond.

Constellation-X would peer at matter falling into supermassive black holes. The planned probes would investigate the nature of dark energy, the physics of the Big Bang, and the distribution and types of black holes in the universe.

LISA is one project under study by the Einstein Probes Office. To study gravitational waves, LISA would “float” over them, much like a buoy on choppy seas. Image credit: NASA

Original Source: NASA will study Strange Cosmic Phenomena
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Einstein's Theory of General Relativity ~podcast~ from Universe Today
Spitzer Finds Water Vapour on Hot, Alien Planet press release 11/07/07
NASA's Stardust & Deep Impact to Observe More Comets And Extrasolar Planets
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Summer Moon Illusion

Sometimes you can't believe your eyes. This weekend is one of those times. On Saturday night, June 30th, step outside at sunset and look around. You'll see a giant moon rising in the east. It looks like Earth's moon with the usual craters and seas, but something's wrong. This full moon is strangely inflated. It's huge!

You've just experienced the Moon Illusion.

Sky watchers have known for thousands of years that low-hanging moons look unnaturally big. Cameras don't see it, but human eyes do; it's a genuine illusion.

Above: A time-lapse sequence of the moon rising over Seattle. To the camera, the moon appears to be the same size no matter what its location on the sky. Credit and copyright: Shay Stephens.

Read more Summer Moon Illusion from NASA
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NASA mission to Ceres & Vesta

Dawn Spacecraft launch from Cape Canaveral scheduled for July 7th

Dawn will conduct a detailed study of the structure and composition of two of the first bodies formed in our solar system: the "dwarf planet" Ceres and the massive asteroid Vesta. The mission's goals include determining the shape, size, composition, internal structure, the tectonic and thermal evolution of Vesta and Ceres.

Dawn, which will be the first spacecraft to orbit two planetary bodies on the same mission, is expected to reveal the conditions under which these objects formed. Comparing their different evolutionary paths will provide evidence about the role of size and water in planetary evolution.

Dawn is scheduled to fly past Mars by April 2009, and after more than four years of travel, the spacecraft will rendezvous with Vesta in 2011. The spacecraft will orbit Vesta for approximately nine months, studying its structure and composition. In 2012, Dawn will leave for a three-year cruise to Ceres. Dawn will rendezvous with Ceres and begin orbit in 2015, conducting studies and observations for at least five months.

Read more NASA's Dawn Mission from Science Daily
Artist's impression of the Dawn spacecraft. (Credit: W.K. Hartmann Courtesy / UCLA)
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Swift sees double Supernova

NASA's Swift Sees Double Supernova
Credit: Stefan Immler NASA/GSFC,
Swift Science Team.

Two supernovae have flared up in an obscure galaxy in the Hercules constellation.
Never before have astronomers observed two of these powerful stellar explosions occurring in the same galaxy so close together in time.

The galaxy, known as MCG +05-43-16, is 380 million light-years from Earth. Until this year, astronomers had never sighted a supernova popping off in this stellar congregation. A supernova is an extremely energetic and life-ending explosion of a star.

Making the event even more unusual is the fact that the two supernovae belong to different types:

Supernova 2007ck is a Type II event – which is triggered when the core of a massive star runs out of nuclear fuel and collapses gravitationally, producing a shock wave that blows the star to smithereens. Supernova 2007ck was first observed on May 19.

In contrast, Supernova 2007co is a Type Ia event, which occurs when a white dwarf star accretes so much material from a binary companion star that it blows up like a giant thermonuclear bomb. It was discovered on June 4, 2007. A white dwarf is the exposed core of a star after it has ejected its atmosphere; it’s approximately the size of Earth but with the mass of our Sun.

"Most galaxies have a supernova every 25 to 100 years, so it’s remarkable to have a galaxy with two supernovae discovered just 16 days apart," says Stefan Immler. In 2006 Immler used NASA’s Swift satellite to image two supernovae in the elliptical galaxy NGC 1316, but both of those explosions were Type Ia events, and they were discovered six months apart.

The simultaneous appearance of two supernovae in one galaxy is an extremely rare occurrence, but it’s merely a coincidence and does not imply anything unusual about MCG +05-43-16.

Because the two supernovae are tens of thousands of light-years from each other, and because light travels at a finite speed, astronomers in the galaxy itself, or in a different galaxy, might record the two supernovae exploding thousands of years apart.
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Screaming CMEs

Coronal Mass Ejections (CMEs) begin when the sun launches a billion tons of electrically conducting gas (plasma) into space at millions of miles per hour.

A CME cloud is laced with magnetic fields, and CMEs directed our way smash into Earth's magnetic field. If the CME magnetic fields have the correct orientation, they dump energy into Earth's magnetic field, causing magnetic storms. These storms can cause widespread blackouts by overloading power line equipment with extra electric current. But wait; there's more.

Some CMEs also bring intense radiation storms that can disable satellites or cause cancer in unprotected astronauts. As the CME blasts through space, it plows into a slower stream of plasma blown constantly from the sun in all directions, called the solar wind. The CME causes a shock wave in the solar wind. If the shock is strong enough, it accelerates electrically charged particles that make up the solar wind to high speeds, forming the radiation storm.

For animation and more, visit NASA screaming CMEs
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Colliding Supergiants

This false-color image from the Curtis Schmidt Telescope in Chile shows a large star-forming region in the Large Magellanic Cloud. The binary system LH54-425 is arrowed. It is located in the star cluster LH54.
Credit: Chris Smith and the University of Michigan Curtis Schmidt Telescope at CTIO.

Using NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite and ground-based telescopes, astronomers have determined, for the first time, the properties of a rare, extremely massive, and young binary star system.

The merger of two massive stars to make a single super star of over 80 suns could lead to an object like Eta Carinae, which might have looked like LH54-425 one million years ago.

Finding stars this massive so early in their life is very rare. These results expand our understanding of the nature of very massive binaries, which was not well understood. The system will eventually produce a very energetic supernova.

The system, known as LH54-425, is located in the Large Magellanic Cloud, a satellite galaxy of our Milky Way. The binary consists of two O-stars, the most massive and luminous types of stars in the Universe.
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Spectra obtained by Georgia State University astronomer Stephen Williams at the 1.5-meter (4.9 foot) telescope at the Cerro Tololo Inter-American Observatory in Chile show that the two stars contain about 62 and 37 times the mass of our Sun. “The stars are so close to each other - about one-sixth the average Earth-Sun distance - that they orbit around a common center of mass every 2.25 days,” says Douglas Gies of Georgia State University, Atlanta. With a combined mass of about 100 suns, the system is one the most extreme binaries known. The stars are probably less than 3 million years old.

Each star blows off a powerful stellar wind, and FUSE’s observations have provided the first details of what happens when the two supersonic winds collide. The wind collision zone wraps around the smaller star and produces a curved surface of superheated gases that emit X-rays and far-ultraviolet radiation. FUSE is ideal for these measurements because the lines that best indicate the properties of stellar winds show up in the far ultraviolet part of the spectrum, where FUSE is most sensitive.


FUSE project scientist George Sonneborn of NASA Goddard Space Flight Center, presented these results today in a poster at the spring 2007 American Astronomical Society meeting in Honolulu, Hawaii.

The more massive star is shedding material at a rate of 500 trillion tons per second (about 400 times greater than the rate the sun loses mass through the solar wind), with a speed of 5.4 million miles per hour. The smaller star is ejecting mass at about one-tenth the rate of its sibling. The mass loss rate of both stars is consistent with other single stars having the same temperature and luminosity.

As the stars age and swell in size, they will begin to transfer substantial amounts of mass to each other. This process could begin in a million years. The stars are orbiting so close to each other that they are likely to merge as they evolve, producing a single extremely massive star like the more massive member of the Eta Carinae binary system. Eta Carinae is one of the most massive and luminous stars in the Milky Way Galaxy, with perhaps 100 solar masses.

NASA's FUSE Satellite Catches Collision of Titans
by Bob Naeye - Goddard Space Flight Center.
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Solar Radiation Storm

Solar radiation storms are swarms of electrons, protons and heavy ions accelerated to high speed by explosions on the sun. Here on Earth we are protected from these particles by our planet's atmosphere and magnetic field.

Astronauts in Earth orbit are fairly safe, too; Earth's magnetic field extends out far enough to shield them. The danger begins when astronauts leave this protective cocoon. The Moon and Mars, for instance, have no global magnetic fields, and astronauts working on the surface of those worlds could be at risk.

Spacecraft and satellites are also affected. Subatomic particles striking CPUs and other electronics can cause onboard computers to suddenly reboot or issue nonsense commands. If, say, a satellite operator knows that a storm is coming, he can put his craft in a protective "safe mode" until the storm passes.

The type of particle most feared by astronaut safety experts is the ion, that is, an atom which has lost one or more of its charge-balancing electrons. Energetic ions can damage tissue and break strands of DNA, causing health problems ranging from nausea to cataracts to cancer.
[+/-] Click here to expand

So the goal is to predict when the ions will arrive. The key it turns out, are electrons. Electrons are always detected ahead of the more dangerous ions.

This has been known for years, but only recently has research turned the electrons first aspect of radiation storms into a forecasting tool.

The key to the breakthrough was the COSTEP instrument onboard SOHO. COSTEP is short for "Comprehensive Suprathermal and Energetic Particle Analyzer." Essentially, the device counts particles coming from the sun and measures their energies.

Arik Posner, a physicist in NASA's Science Mission Directorate, looked at hundreds of radiation storms recorded by COSTEP between 1996 and 2002, and was able to construct an empirical, predictive matrix that can be used to forecast the ions' arrival time from the electron data.

Posner's ion storm forecasting matrix.
After testing the results, the matrix was used on COSTEP data gathered in 2003, a year that had not yet been analyzed and formed no part of the matrix itself. The matrix was applied to the electron data and as a result, it successfully predicted all four major ion storms of 2003 with advance warnings ranging from 7 to 74 minutes. The method did, however, also create three false alarms from the 2003 dataset. Improvements will come as Posner works his way through even more of COSTEP's dataset.

The Solar and Heliospheric Observatory (SOHO), is a project of international cooperation between ESA and NASA.
Artist's concept of a radiation storm approaching Earth. Courtesy of Dr. Tony Phillips

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Cosmic rays pose a threat to astronauts bound for Mars.
Researchers discuss what a big proton storm might do to someone on the Moon.
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Solar System goes for a Ride

When Galaxies Collide, our Solar System Will Go for a Ride

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Illustration: NASA/CXC/M.Weiss

For decades, astronomers have known that the Milky Way galaxy is on a collision course with the neighboring Andromeda spiral galaxy. What was unknown until now: the fate of the Sun and our solar system in that melee. New calculations by theorists T.J. Cox and Avi Loeb (Harvard-Smithsonian Center for Astrophysics) show that the Sun and its planets will be exiled to the outer reaches of the merged galaxy. Moreover, the collision will take place within the Sun's lifetime, before it becomes a burned-out white dwarf star.

"You could say that we're being sent to a retirement home in the country," said Cox. "We're living in the suburbs of the Milky Way right now, but we're likely to move much farther out after the coming cosmic smash-up."

Computer simulations by Cox and Loeb show that big changes are coming in only 2 billion years, when the Milky Way and Andromeda experience their first close pass. A viewer on Earth would see the night sky evolve from a strip of stars (the Milky Way seen edge-on) to a muddled mess as Andromeda's powerful pull flings stars from their stately orbits.

At that time, the Sun will still be a hydrogen-burning main-sequence star, although it will have brightened and heated enough to boil the oceans from the Earth.

The two galaxies will swing around each other a couple of times, intermingling their stars as gravitational forces stir them together. CfA animation movie

About 5 billion years from now, Andromeda and the Milky Way will have completely combined to form a single, football-shaped elliptical galaxy. The Sun will be an aging star nearing the red giant phase and the end of its lifetime. It and the solar system likely will reside 100,000 light-years from the center of the new galaxy - 4 times further than the current 25,000 light-year distance.

Any descendants of humans observing the future sky will experience a very different view. The strip of Milky Way will be gone, replaced by a huge bulge of billions of stars. Future scientists may look back on today's research as the first prediction of things to come.

"This is the first paper in my publication record that has a chance of being cited five billion years from now," joked Loeb.

The paper describing this research has been submitted for publication to the Monthly Notices of the Royal Astronomical Society.
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A Galactic Collision, and the Sun’s Future from Centauri Dreams
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Cat's Eye Nebula

The Cat's Eye Nebula from Hubble Credit: NASA, ESA, HEIC, and The Hubble Heritage Team (STScI/AURA) Click on Image to Enlarge

Staring across interstellar space, the alluring Cat's Eye nebula lies three thousand light-years from Earth. A classic planetary nebula, the Cat's Eye (NGC 6543) represents a final, brief yet glorious phase in the life of a sun-like star. This nebula's dying central star may have produced the simple, outer pattern of dusty concentric shells by shrugging off outer layers in a series of regular convulsions.
But the formation of the beautiful, more complex inner structures is not well understood. Seen so clearly in this sharp Hubble Space Telescope image, the truly cosmic eye is over half a light-year across. Of course, gazing into the Cat's Eye, astronomers may well be seeing the fate of our sun, destined to enter its own planetary nebula phase of evolution ... in about 5 billion years.
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Brightest Supernova

U.S. astronomers say an exploding star first observed in September 06 has become the largest and most luminous supernova ever seen.

According to observations by NASA's Chandra X-ray Observatory and ground-based optical telescopes, the supernova SN 2006gy is the brightest and most energetic stellar explosion ever recorded and may be a long-sought new type of explosion.

The top panel of this graphic is an artist's illustration that shows what SN 2006gy may have looked like if viewed at a close distance. The fireworks-like material in white shows the explosion of an extremely massive star. This debris is pushing back two lobes of cool, red gas that were expelled in a large eruption from the star before it exploded. The green, blue and yellow regions in these lobes shows where gas is being heated in a shock front as the explosion material crashes into it and pushes it backwards. Most of the optical light generated by the supernova is thought to come from debris that has been heated by radioactivity, but some likely comes from the shocked gas.

The bottom left panel is an infrared image, using adaptive optics at the Lick Observatory, of NGC 1260, the galaxy containing SN 2006gy. The dimmer source to the lower left in that panel is the center of NGC 1260, while the much brighter source to the upper right is SN 2006gy.

The panel to the right shows Chandra's X-ray image of the same field of view, again showing the nucleus of NGC 1260 and SN 2006gy. The Chandra observation allowed astronomers to determine that SN 2006gy was indeed caused by the collapse of an extremely massive star, and not the most likely alternative explanation for the explosion, the destruction of a low-mass star. If the supernova was caused by a white dwarf star exploding into a dense, hydrogen-rich environment, SN 2006gy would have been about 1,000 times brighter in X-rays than what Chandra detected.

NASA's Chandra Sees Brightest Supernova Ever
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