Thursday, November 30, 2006

Starburst Galaxy

Starburst Galaxy NGC1313 Credit ESO ENLARGE Image

The captivating appearance of this image of the starburst galaxy NGC 1313, taken with the FORS instrument at ESO's Very Large Telescope, belies its inner turmoil. The dense clustering of bright stars and gas in its arms, a sign of an ongoing boom of star births, shows a mere glimpse of the rough times it has seen. Probing ever deeper into the heart of the galaxy, astronomers have revealed many enigmas that continue to defy our understanding.

The galaxy bears some resemblance to some of the Milky Way's closest neighbours, the Magellanic Clouds. NGC 1313 has a barred spiral shape, with the arms emanating outwards in a loose twist from the ends of the bar. The galaxy lies just 15 million light-years away from the Milky Way - a mere skip on cosmological scales. The spiral arms are a hotbed of star-forming activity, with numerous young clusters of hot stars being born continuously at a staggering rate out of the dense clouds of gas and dust. Their light blasts through the surrounding gas, creating an intricately beautiful pattern of light and dark nebulosity.

Starburst galaxies are fascinating objects to study in their own right; in neighbouring galaxies, around one quarter of all massive stars are born in these powerful engines, at rates up to a thousand times higher than in our own Milky Way Galaxy.

In the majority of starbursts the upsurge in star's births is triggered when two galaxies merge, or come too close to each other. The mutual attraction between the galaxies causes immense turmoil in the gas and dust, causing the sudden 'burst' in star formation.

Galaxy NGC1313
view further out
credit ESO
(AAO/ROE/Digital SKy Survey)

Strangely enough NGC 1313 seems to be an isolated galaxy. It is not part of a group and has no neighbour, and it is not clear whether it may have swallowed a small companion in its past. So what caused its asymmetry and stellar baby boom?

An explanation based on the presence of the central bar also does not hold for NGC 1313: the majority of its star formation is actually taking place not in its bar but in dense gassy regions scattered around the arms. By what mechanism the gas is compressed for stars to form at this staggering rate, astronomers simply aren't sure.

In the midst of the cosmic violence of the starburst regions lie two objects that emit large amounts of highly energetic X-rays - so-called ultra-luminous X-ray sources (ULX). Astronomers suspect that they might be black holes with masses of perhaps a few hundred times the mass of our Sun each, that formed as part of a binary star system. How such objects are created out of ordinary stars cannot be conclusively explained by current models.

ESO outreach press release 23rd Nov 2006
van den bergh 152 by Giovanni Benintende @ Universe Today
Where do baby stars come from podcast @ Universe Today
"The more you know the less you need to say." - Jim Rohn

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Tuesday, November 28, 2006

Gamma Ray Astronomy

PPARC simulation of the Microquasar LS5039 ENLARGE Image
This image was created using software developed by Dr. Rob Hynes of LSU.

Gamma-rays are produced in extreme cosmic particle accelerators such as supernova explosions and provide a unique view of the high energy processes at work in the Milky Way.

VHE (very high energy) gamma-ray astronomy is still a young field and the High Energy Stereoscopic System (H.E.S.S.) is conducting the first sensitive survey at this energy range, finding previously unknown sources.

The object that is producing the high energy radiation is thought to be a 'microquasar'. These objects consist of two stars in orbit around each other. One star is an ordinary star, but the other has used up all its nuclear fuel, leaving behind a compact corpse. Depending on the mass of the star that produced it, this compact object is either a neutron star or a black hole, but either way its strong gravitational pull draws in matter from its companion star. This matter spirals down towards the neutron star or the black hole, in a similar way to water spiraling down a plughole.

However, sometimes the compact object receives more matter than it can cope with. The material is then squirted away from the system in a jet of matter moving at speeds close to that of light, resulting in a microquasar. Only a few such objects are known to exist in our galaxy and one of them, an object called LS5039, has now been detected by the H.E.S.S. team.
[+/-] click to expand

The companion star to the compact object is a massive star that is losing material from its surface. This matter is then captured by the compact object's strong gravitational field and spirals down towards the surface. Some of this material is then ejected in two jets travelling at 20% of the speed of light. In fact, the real nature of LS5039 is something of a mystery. It is not clear what the compact object is. Some of the characteristics suggest it is a neutron star, some that it is a black hole. Not only that, but the jet isn't much of a jet; although it is moving at about 20% of the speed of light, which might seem a lot, in the context of these objects it's actually quite slow.

Nor is it clear how the gamma rays are being produced. Very high energy gamma rays emitted close to the companion star are more likely to be absorbed, creating a matter/antimatter cascade, than escape from the system.

The results were obtained using the High Energy Stereoscopic System (H.E.S.S.) telescopes in Namibia, in South-West Africa. This system of four 13 m diameter telescopes is currently the most sensitive detector of VHE gamma-rays - radiation that is a million, million times more energetic than the visible light.

These high energy gamma rays are quite rare even for relatively strong sources; only about one gamma ray per month hits a square metre at the top of the Earth's atmosphere. Also, since they are absorbed in the atmosphere, a direct detection of a significant number of the rare gamma rays would require a satellite of huge size.

The H.E.S.S. telescopes employ a trick - they use the atmosphere as detector medium. When gamma rays are absorbed in the air, they emit short flashes of blue light, named Cherenkov light, lasting a few billionths of a second. This light is collected by the H.E.S.S. telescopes with large mirrors and extremely sensitive cameras and can be used to create images of astronomical objects as they appear in gamma-rays.

More from PPARC PressRelease:
Mystery compact object producing high energy radiation
Integral Catches a new erupting blackhole

ESA's gamma-ray observatory, Integral, has spotted a rare kind of gamma-ray outburst.

The vast explosion of energy allowed astronomers to pinpoint a possible black hole in our Galaxy.

The outburst was discovered on 17 September 2006 by staff at the Integral Science Data Centre (ISDC), Versoix, Switzerland.

"The galactic centre is one of the most exciting regions for gamma ray astronomy because there are so many potential gamma-ray sources," says Roland Walter, an astronomer at the ISDC, and lead author of these results.

In this case, the outburst continued to rise in brightness for a few days before beginning a gradual decline that lasted for weeks. The way the brightness of an outburst rises and falls is known to astronomers as a light curve. "It was only after a week that we could see the shape of the light curve and realised what a rare event we had observed," says Walter.

Comparing the shape of the light curve to others on file revealed that this was an eruption thought to come from a binary star system in which one component is a star like our Sun whereas the other is a black hole.

In these systems, the gravity of the black hole is ripping the Sun-like star to pieces. As the doomed star orbits the black hole, it lays down its gas in a disc, know as an accretion disc, surrounding the black hole.

Occasionally, this accretion disc becomes unstable and collapses onto the black hole, causing the kind of outburst that Integral witnessed. Astronomers are still not sure why the accretion disc should collapse like this but one thing is certain: when it does collapse, it releases thousands of times the energy than at other times.

Because such active star–black hole binaries are thought to be rare in the Galaxy, astronomers expect Integral to see such an outbursts only once every few years. That makes each and every one a precious resource for astronomers to study.

INTEGRAL catches a new erupting black hole
Additional Material to ESA's Press Release of 27 Nov. 2006

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Monday, November 27, 2006

Twin Star Explosions

(Credit: NASA/Swift/Stefan Immler) using NASA's Swift satellite

Scientists using NASA's Swift satellite stumbled upon a rare sight: two supernovas side by side in one galaxy. Large galaxies typically play host to three supernovas per century. Galaxy NGC 1316 has had two supernovas in less than five months, and a total of four supernova in 26 years, as far back as the records go. This makes NGC 1316 one of the most prodigious known producer of supernovas.

An image of the two supernovas side by side in the galaxy NGC 1316 is pictured here. The first supernova, still visible on the "right" in the image, was detected on June 19, 2006, and was named SN 2006dd. The second supernova, on the immediate "left" in the image, was detected on November 5 and has been named SN 2006mr. (Other objects in the image include a central bright spot, which is the galaxy core, and a bright object to the far left, like an earring, which is a foreground star.)

NGC 1316, a massive elliptical galaxy about 80 million light years way, has recently merged with a spiral galaxy. Mergers do indeed spawn supernovas by forcing the creation of new, massive stars, which quickly die and explode. Yet all four supernovas in NGC 1316 appear to be Type Ia, a variety previously not associated with galaxy mergers and massive star formation. Scientists are intrigued and are investigating whether the high supernova rate is a coincidence or a result of the merger.

Swift was launched two years ago, on 20 November 2004, was fully operational by January 2005, and since then has observed more than 200 gamma-ray bursts plus more than a thousand other astronomical objects.

Penn State edu - Swift alert 21st Nov 2006
More to starlight than meets the Eye

Image courtesy of Clemson University

The solar system is located at the outskirts of a majestic spiral galaxy, like the one shown in this simulated image. While it is difficult to obtain such an image from our inside location, many astronomical observations indicate that the picture shown here is a good representation.

Star counts in the infrared part of the electromagnetic spectrum with NASA's recently launched Spitzer Space Telescope led to this image, which shows that the central region has a large bar (also seen in many distant spiral galaxies) and pronounced spiral arms. Much of the star formation traced by the gamma-rays from 26-aluminum originates in stellar explosions (supernovae) that quickly follow the formation of massive stars along these spiral arms. As the spiral pattern rotates through the gas in a galaxies disk, the most massive stars light up the galaxy and seed the gas with freshly synthesized elements that are so essential to the evolution of life.

Where do elements, such as iron in our blood or calcium in our bones, come from? Astronomers say they come from thermonuclear reactions in hundreds of millions of stars that burn at high temperatures in our galaxy. Stars that are 10 or more times more massive than the sun eventually explode as supernovas, leaving traces of elements in the space between the stars of the Milky Way. When our solar system was created, astronomers say the trace elements were drawn from interstellar gases to form the Earth.

“Life depends on stars creating elements we so desperately need,” says Clemson University astrophysicist Dieter Hartmann. “It’s these elements that support life here on Earth and probably elsewhere.”

Read more >>> Science Daily release
Time is of your own making; its clock ticks in your head.
The moment you stop thought time too stops dead. Angelus Silesius

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Saturday, November 25, 2006

Glimpses of Solar light


Ramallah sunset : A minaret is silhouetted as the sun sets over the West Bank city of Ramallah. (AFP/Abbas Momani)

Northern lights dance across the sky near Palmer, Alaska, Wednesday, Nov. 22, 2006. (AP Photo/Bob Martinson)

See More spectacular pictures of
Northern Lights

Into the LIGHT
Rehearsal in Seville : Mares perform during a rehearsal of Sicab 2006, the International Horse Show of Spain, in Seville. (AFP/Cristina Quicler)

Where visible light cannot travel thru

Six years after its construction began, the CNGS facility at CERN has sent its first batch of neutrinos 732 km to Gran Sasso in Italy in a highly successful commissioning run.

The CERN Neutrinos to Gran Sasso (CNGS) facility was built to create a neutrino beam to search for oscillations between muon-neutrinos and tau-neutrinos. An intense, almost 100% pure beam of muon-neutrinos is produced at CERN in the direction of the Laboratorio Nazionale del Gran Sasso (LNGS), almost 732 km away in Italy . There, the OPERA experiment (see CERN Courier November 2006 p24) is being constructed to find interactions of tau-neutrinos among those of other neutrinos.

The production of the CNGS beam of muon-neutrinos follows the "classic" scheme that was first used in the 1960s at Brookhaven and CERN, and has been refined ever since. An intense proton beam from CERN's Super Proton Synchrotron (SPS) is sent to strike a target, in this case graphite. Protons that interact with nuclei in the target produce many particles, mostly unwanted, but including positively charged pions and kaons – mesons that decay naturally into pairs of muons and muon-neutrinos.

Two magnetic lenses – the horn and the reflector – collect these mesons within a selected momentum range and focus them into a parallel beam towards LNGS. After a decay tube nearly 1 km long, all the hadrons – i.e. protons that have not interacted in the target, pions and kaons that have not yet decayed, and so on – are absorbed in a hadron stopper; only neutrinos and muons can traverse this solid block of graphite and iron.

The muons, which are ultimately absorbed downstream in around 500 m of rock, are measured first in two detector stations. Only the neutrinos are left to travel onwards through the top layer of the Earth's crust towards LNGS.

Konrad Elsener, Edda Gschwendtner and Malika Meddahi @ CERN courier

The neutrino is of scientific interest because it can make an exceptional probe for environments that are typically concealed from the standpoint of other observation techniques, such as optical and radio observation.
[+/-] Click here to expand

The first such use of neutrinos was proposed in the early 20th century for observation of the core of the Sun. Direct optical observation of the solar core is impossible due to the diffusion of electromagnetic radiation by the huge amount of matter surrounding the core. On the other hand, neutrinos generated in stellar fusion reactions are very weakly interacting and therefore pass right through the sun with few or no interactions. While photons emitted by the solar core may require 1,000 years to diffuse to the outer layers of the Sun, neutrinos are virtually unimpeded and cross this distance at nearly the speed of light.

Neutrinos are also useful for probing astrophysical sources beyond our solar system. Neutrinos are the only known particles that are not significantly attenuated by their travel through the interstellar medium. Optical photons can be obscured or diffused by dust, gas and background radiation. High-energy cosmic rays, in the form of fast-moving protons and atomic nuclei, are not able to travel more than about 100 megaparsecs due to the GZK cutoff. Neutrinos can travel this distance, and greater distances, with very little attenuation.

The galactic core of the Milky Way is completely obscured by dense gas and numerous bright objects. However, it is likely that neutrinos produced in the galactic core will be measurable by Earth-based neutrino telescopes in the next decade.

The most important use of the neutrino is in the observation of supernovae, the explosions that end the lives of highly massive stars. The core collapse phase of a supernova is an almost unimaginably dense and energetic event. It is so dense that no known particles are able to escape the advancing core front except for neutrinos. Consequently, supernovae are known to release approximately 99% of their energy in a rapid (10 second) burst of neutrinos. As a result, the usefulness of neutrinos as a probe for this important event in the death of a star cannot be overstated.

Determining the mass of the neutrino is also an important test of cosmology. Many other important uses of the neutrino may be imagined in the future. It is clear that the astrophysical significance of the neutrino as an observational technique is comparable with all other known techniques, and is therefore a major focus of study in astrophysical communities.

In particle physics the main virtue of studying neutrinos is that they are typically the lowest mass, and hence lowest energy examples of particles theorized in extensions of the Standard Model of particle physics. For example, one would expect that if there is a fourth class of fermions beyond the electron, muon, and tau generations of particles, that a fourth generation neutrino would be the easiest to generate in a particle accelerator.

Neutrinos are also obvious candidates for use in studying quantum gravity effects. Because they are not affected by either the strong interaction or electromagnetism, and because they are not normally found in composite particles (unlike quarks) or prone to near instantaneous decay (like many other standard model particles) it is easier to isolate and measure gravitational effects on neutrinos at a quantum level.

Neutrinos for beginners & Icecream by Sabine Hossenfelder
Tunnelling in Faster than Light by Plato @ Dialogues of Eide

Thursday, November 23, 2006

The Sun's Poles

Credits: JPL-ESA, 1994 ESA Space

Ulysses starts third passage over the Sun's south pole.

Launched in 1990, the European-built spacecraft is engaged in the exploration of the heliosphere, the bubble in space blown out by the solar wind. Given the capricious nature of the Sun, this third visit will undoubtedly reveal new and unexpected features of our star's environment.

The first polar passes in 1994 (south) and 1995 (north) took place near solar minimum, whereas the second set occurred at the height of solar activity in 2000 and 2001.

As Ulysses approaches the polar regions for the third time, the Sun has settled down once again and will be close to its minimum. Ulysses orbits the Sun once every 6.2 years, making it perfect for studying the 11-year solar activity cycle. One can really say that Ulysses is exploring the heliosphere in four dimensions - covering all three spatial dimensions as well as time.

Even though the Sun will be close to its activity minimum just as it was in 1994-95, there is one fundamental difference: the Sun's magnetic field has reversed its polarity. In addition to the 11-year activity cycle, the Sun has a magnetic cycle of 22 years, known as the Hale Cycle. Ulysses, now in its 17th year in orbit, is giving scientists the chance to observe the heliosphere from a unique, out-of-ecliptic vantage point and with the same set of instruments over almost a complete Hale Cycle.

The Ulysses science team is expecting to find that the change in polarity of the Sun's magnetic field will have a clear effect on the way cosmic ray particles reach our location in the inner heliosphere. During the last solar minimum, positively charged particles had a slightly easier time reaching the polar regions; this time, the negatively charged electrons should have the advantage.

But there could be surprises. In 1994, the pole-to-equator difference in the number of particles observed, although present, was much smaller than expected. This lead to several new models for the way charged particles move in the complex environment of interplanetary space. The new observations will test if these new theories are correct.

Another surprise from the first polar passes was the fact that the heliosphere is not as symmetric as previously believed. The Sun's magnetic field was found to be slightly stronger in the south than in the north. Scientists be watching out for this effect as Ulysses swings from the south pole to the north in 2007.

Ulysses returns to the Sun's polar cap NASA release 20th Nov 2006
Ulysses embarks on third set of polar passes 17th November 2006
Ulysses Starts New Journey Around The Sun's Poles 21st Nov 2006
The Weblog Awards 2006 - A chance for you to nominate
the best Educational Blogs >>> Nominations Best Science Blogs
Famous Quotes
Action is the foundational key to all success. Pablo Picasso

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Wednesday, November 22, 2006

Glory in the Skies

A Multi-ring glory surrounds an aircraft's shadow. by Philip Laven

A glory is an optical phenomenon produced by light backscattered (a combination of diffraction, reflection and refraction) towards its source by a cloud of uniformly-sized water droplets. A glory has multiple colored rings. The angular size is much smaller than a rainbow, about 5° to 20°, depending on the size of the droplets.

Since it is seen in the direction opposite the sun, it is most commonly observed when on a mountain above the clouds, or while airborne, with the glory surrounding the airplane's shadow on clouds.

If you look toward the antisolar point, the place in the clouds directly opposite the sun, if the aircraft is low enough, you will find the shadow of the plane. Surrounding the shadow is the glory, a bright white glow surrounded by one or more shimmering rings of color.

These rings are formed when light is scattered backwards by individual water droplets in the cloud. The more uniform the size of the droplets, the more rings you will see. They swell and contract as you travel over clouds with smaller or larger droplets.

In China, this phenomenon is called Buddha's light (佛光). It was often observed on cloud-shrouded high mountains, such as Huangshan Mountains and Mount Emei. Records of the phenomenon at Mount Emei date back to A.D. 63. The colorful halo always surrounds the observer's own shadow, and thus was often taken to show the observer's personal enlightenment (associated with Buddha or something divine) until modern science explained the optics behind the phenomenon.

Atmospheric Optics by Les Cowley
Thanksgiving Skies by Dr Tony Phillips @ NASA 21 Nov 2006
Airglow by Astroprof @ Astroprof's Page
Fog Bow over California Astronomy Picture of the day
Central theme is the Sun by Plato @ Dialogues of Eide
Double Rainbow from Annelisa Lynch @ Words that flow
The Weblog Awards 2006 - A chance for you to nominate
the best Educational Blogs >>> Nominations Best Science Blogs

Monday, November 20, 2006

Awesome Detectors



The Sudbury Neutrino Observatory is a collaborative effort among physicists from Canada, the U.K., and the U.S. Using 1,000 tons of so-called heavy water and almost 10,000 photon detectors, they measure the flux, energy, and direction of solar neutrinos, which originate in the sun. SNO, located 6,800 feet underground in an active Ontario nickel mine, can also detect the other two types of neutrinos, muon neutrinos and tau neutrinos. In 2001, just two years after the observatory opened, physicists at SNO solved the 30-year-old mystery of the "missing solar neutrinos." They found that the answer lies not with the sun—where many physicists had suspected that solar neutrinos undergo changes—but with the journey they take from the core of the sun to the Earth.

2001-2002: Proof of solar neutrino oscillation
The Sudbury Neutrino Observatory (SNO), the first neutrino detector that can pick up all three known types of neutrinos, resolves conclusively that, in the case of the missing solar neutrinos, the neutrinos are not, in fact, missing. SNO finds that the total number of neutrinos from the sun is remarkably close to what John Bahcall predicted three decades earlier. Ray Davis's experimental work is vindicated as well, because SNO finds that only about a third of the solar neutrinos that reach Earth are still in the same state that Davis could measure. Roughly two-thirds change type—or oscillate—during the journey.

The Ghost Particle homepage
Case of the Missing Particles
Neutrinos for beginners by Sabine Hossenfelder
Result of effective changes in the cosmos by Plato
The Weblog Awards 2006 - A chance for you to nominate
the best Educational Blogs >>> Nominations Best Science Blogs

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Saturday, November 18, 2006

Night of Falling Stars

The Leonids 2001 by Wally Pacholka, ENLARGE Image
Joshua Tree National Park, near Palm Springs, California, USA Nov. 18

"The Night of the Falling Stars,"
is a composite of four one-minute exposures.

Expect a Meteor shower of Leonids on Sunday, Nov. 19th
as Earth passes through a stream of debris from a comet

Astronomy Picture of The Day - The Leonids
Space Weather gallery - The Leonids 19 Nov 2006

And from Sunflower Optimism in the spirit of making a wish,
a link to those making small dreams come true @ Make A Wish

Friday, November 17, 2006

Wishing On A Star

"These Leonids are shooting right through the Southern Cross."
The Leonids 2001 by
Greg Quicke, Broome, Western Australia Nov. 18

Expect a Meteor shower of Leonids on Sunday, Nov. 19th
Earth will pass through a stream of debris from comet 55P/Tempel-Tuttle

"We expect an outburst of more than 100 Leonids per hour," says Bill Cooke, the head of NASA's Meteoroid Environment Office in Huntsville, AL. This pales in comparison to the Leonid storms of 2001 and 2002, when sky watchers saw thousands of meteors. Even so, a hundred per hour would make the Leonids one of the best showers of 2006.

The mid-November region of Earth's orbit is littered with debris from Comet Tempel-Tuttle. Every time the comet visits the inner solar system (once every 33 years), it lays down a new stream of dust, pebbles and rock. This creates a sort of "minefield" for Earth to navigate every November.

Not all of these debris streams are alike. For example: A Leonid stream we hit in 1998 was full of rock-sized debris. They made brilliant fireballs when they hit the atmosphere. The stream we're hitting this year is just the opposite. It's mostly fine dust.

Left: A minefield of Leonid debris streams. The streams intersect the plot at nearly right angles, so they resemble 2D clouds rather than 3D filaments. Credit J. Vaubaillon.

Debris streams are segregated—dusty vs. rocky—by the force of sunlight. Consider the stream directly ahead of us: "It was ejected from the comet in 1933," says Cooke. "At first, the debris was a mixture of many sizes." But as years passed, the smaller particles diverged from the larger ones. Radiation pressure—the delicate pressure of sunlight itself—pushed the light dust onto a collision course with Earth. Heavier rock-sized fragments resisted the pressure and lagged behind.

Perhaps in some future year we'll encounter the larger debris from 1933 and receive an overdue display of fireballs. How would they get here? "Nudged by Jupiter," suggests Cooke. Jupiter's gravity is strong enough to alter the course of heavier fragments. Indeed, by guiding debris toward us, Jupiter is indirectly responsible for many bright Leonid displays in the past.

While meteor forecasters have done a splendid job predicting Leonid outbursts in recent years — they could be wrong in 2006. The outburst might happen at an unexpected time or it might be better than expected.

Cooke urges enthusiasts everywhere to keep an eye out for Leonid meteors the nights of Nov. 17th – 19th. "The best time to look," he says, "is just before local dawn when the constellation Leo is high in the sky."

Leonid Photo Gallery Meteors 2001
Return of the Leonids NASA 14 Nov 2006
Discovering the Quantum Universe by Plato
What is dark matter -/- dark energy by Plato
The Three Ring Circus - dark energy by Plato
Have a great weekend, and don't forget "Make a Wish" - Quasar9

Wednesday, November 15, 2006

The Space Foundation

The Space Foundation has publicly released The Space Report: The Guide to Global Space Activity, was released in a series of briefings held today in Washington, D.C., and continuing this week in New York City.

Among its revelations: the space industry now tops $180 billion in global revenues, and a newly created index of space equities has outperformed both the S and P 500 and NASDAQ.

The Space Foundation
Accelerating electrons & Cosmic Rays

This extraordinarily deep Chandra image shows Cassiopeia A (Cas A, for short), the youngest supernova remnant in the Milky Way.

Credit: NASA/CXC/ UMass Amherst/M.D.Stage et al.

For the first time, astronomers have mapped the rate of acceleration of cosmic ray electrons in a supernova remnant. The new map shows that the electrons are being accelerated at close to the theoretically maximum rate. This discovery provides compelling evidence that supernova remnants are key sites for energizing charged particles.

The map was created from an image of Cassiopeia A, a 325-year-old remnant produced by the explosive death of a massive star. The blue, wispy arcs in the image trace the expanding outer shock wave where the acceleration takes place. The other colors in the image show debris from the explosion that has been heated to millions of degrees.

As the total energy of the cosmic rays behind the shock wave increases, the magnetic field behind the shock is modified, along with the character of the shock wave itself. Researching the conditions in the shocks helps astronomers trace the changes of the supernova remnant with time, and ultimately better understand the original supernova explosion.
Chandra Discovers Relativistic Pinball Machine Science Daily 15th Nov 2006

Tuesday, November 14, 2006

Future Energy in the US

Renewable resources could produce 25 percent of the electricity and motor vehicle fuels used in the United States by 2025 at little or no additional cost if fossil fuel prices remain high enough and the cost of producing renewable energy continues falling in accord with historical trends, according to a RAND Corporation study issued today.

Rand: "Renewable Energy Could Play Larger Role In U.S. Future"
from Science Daily 14th November 2006
A bit more gnawing on the Stern bone by Soat @ Science Blogs
The Cosmic connection to climate by Plato

Kavli - Science, Money & Philanthropy
Many scientists lament that money for basic research is becoming harder to obtain, as governments, corporations and other big funders seek specific breakthroughs that can be applied relatively quickly. Kavli, however, is adamant about giving money for open-ended research whose ultimate fruits may not yet be in sight.

Just a few years after seriously beginning his mission to stimulate advances in nanotechnology, neuroscience and astronomy, Kavli has launched 14 research centers in academia's most rarified halls, including Harvard, Yale, Stanford, Caltech and MIT, plus schools in Europe and China. While some are using Kavli's money to probe the nature of "dark matter" in the universe, others are exploring the minuscule brain structures active in human cognition.

Kavli expects to eventually create 20 such centers. And beginning in 2008, $1 million Kavli Prizes in nanotech, neuroscience and astrophysics will be awarded every two years by the Academy of Sciences in Norway, where Kavli was born and first yearned to better grasp man's place in the universe.

"I like to look far into the future," Kavli said in his slightly lilting Norwegian accent. "I think it's important for the benefit of all human beings."

Kavli strives to leave mark on science more from USA Today
Famous Quotes
Reality leaves a lot to the imagination. John Lennon

Monday, November 13, 2006

The Celestial & The Atomic

There is an almost perfect parallel between math describing the motion of celestial objects, like the sun (shown here in an ultraviolet image), and atomic objects.

Image courtesy of NASA

Imagine a group of celestial bodies say, the Sun, the Earth, and a Space craft moving along paths determined by their mutual gravitational attraction.

The mathematical theory of dynamical systems describes how the bodies movein relation to one another. In such a celestial system, the tangle of gravitational forces creates tubular "highways" in the space betweenthe bodies. If the spacecraft enters one of the highways, it is whisked along without the need to use very much energy. With help from mathematicians, engineers and physicists, the designers of the Genesis spacecraft mission used such highways to propel the craft to its destinations with minimal use of fuel.

In a surprising twist, it turns out that some of the same phenomena occur on the smaller, atomic scale. This can be quantified in the study of what are known as "transition states", which were first employed in the field of chemical dynamics. One can imagine transition states as barriers that need to be crossed in order for chemical reactions to occur (for"reactants" to be turned into "products"). Understanding the geometry of these barriers provides insights not only into the nature ofchemical reactions but also into the shape of the "highways" in celestial systems.

The connection between atomic and celestial dynamics arises because the same equations govern the movement of bodies in celestial systems and the energy levels of electrons in simple systems and these equations are believed to apply to more complex molecular systems as well.

This similarity carries over to the problems' transition states; the difference is that which constitutes a "reactant" and a "product" is interpreted differently in the two applications. The presence of the same underlying mathematical description is what unifies these concepts.

Because of this unifying description, it can be said that: "The orbits used to design spacemissions thus also determine the ionization rates of atoms and chemical-reaction rates of molecules!"

The mathematics that unites these two very different kinds of problems is not only of great theoretical interest for mathematicians, physicists, and chemists, but also has practical engineering value in space mission design and chemistry.
More from Science Daily releases 5th October 2005

Dynamic Systems Theory:
The Lorenz attractor &
Gauss' Modular flow

Image by
Etienne Ghys/Jos Leys

A collaboration between a mathematician and an artist-geometer has resulted in some of the most mathematically sophisticated and aesthetically gripping animations ever seen in the field. Their visualizations of cutting-edge research in dynamical systems theory not only provide a dramatic new way of visiting mathematical worlds once seen only in the mind's eye, but also point to a new era for the use of computer graphics in communicating and carrying out mathematical research.

In 1963, the meteorologist Edward Lorenz was studying a very simplified numerical model for the atmosphere, which led him to the amazing strange attractor popularized through the famous butterfly effect: the flapping wings of a butterfly might cause some tiny change in the state of the atmosphere which can in turn lead to hurricanes!
"We would like to describe a close topological connection between these two mathematical objects."
Feature column by Ghys & Leys
More from Science Daily releases 13th Nov 2006
Famous Quotes Fate loves the fearless. James Russell Lowell

Saturday, November 11, 2006

Riding with the Clouds


Awaken to Another Majestic November Morning
puffy white cotton clouds floating lazily in the blue sky
The gentle breeze softly blowing the leaves in the wind,
the 'chill' still in the air warming from the mild radiance
of the bright and yellow star, the sun high up in the sky

And so Nature each dawn brings in the new day
the spirits of horses riding clouds like sun rays
they run and they run just for fun and just to play
this is the nature of spirited horses, this is nature's way
so let me here wish you all a great weekend and a good day!

The one left behind and others from Angel Dust @ Mischief Angel
Showing off some of my paintings from Mysti @ Season for Angels
Sackett's good morning kiss by Montana Gypsy @ katies kaleidoscope
Barn work - Buster with Phil and others from TRF @ Life with Horses

Friday, November 10, 2006

Giant Stellar Flares

Image above: This movie shows a massive solar flare from October 2003, captured by the SOHO satellite. Note the burst of high-speed particles after the flare creating a snowstorm effect. The stellar flare that Swift detected from a star system called II Pegasi was millions of times more powerful. Credit: NASA-ESA/SOHO/EIT

The flaring star in II Pegasi is 0.8 times the mass of the sun; its companion is 0.4 solar masses.
The stars are close, only a few stellar radii apart. As a result, tidal forces cause both stars to spin quickly, rotating in step once in 7 days compared to the sun's 28-day rotation period. Fast rotation is conducive to strong stellar flares.

Young stars spin fast and flare more actively, and the early sun likely generated solar flares on par with II Pegasi. Yet II Pegasi could be at least a billion years older than our middle-aged 5-billion-year-old sun. "The tight binary orbit in II Pegasi acts as a fountain of youth, enabling older stars to spin and flare as strongly as young stars," said Steve Drake of NASA Goddard, a co-author with Osten on an upcoming Astrophysical Journal paper.

The key finding in the II Pegasi flare was the detection of higher-energy X-rays. Swift's Burst Alert Telescope usually detects gamma-ray bursts, the most powerful explosions known, which arise from star explosions and star mergers. The II Pegasi flare was energetic enough create a false alarm for a burst detection. Scientists quickly knew this was a different kind of event, however, when the flare overwhelmed Swift's X-ray Telescope, a second instrument.

Higher-energy "hard" X-ray detection in this case is the telltale signal of electron particle acceleration, creating what is called non-thermal X-rays. NASA's RHESSI mission sees this in the sun's solar flares. While lower-energy "soft" X-rays from thermal emission have been seen on other stars, scientists have never seen hard X-rays on any flaring star other than the sun. Because the hard X-rays occur earlier in the flare and are responsible for heating the coronal gas, they reveal unique information about the flare's initial stages.

Had the sun flared like II Pegasi, these hard X-rays would have overwhelmed the Earth's protective atmosphere, leading to significant climate change and mass extinction. Ironically, one theory posits that stellar particle outbursts are needed to condition dust to form into planets and perhaps life.

The Swift observation demonstrates that such outbursts do occur."Swift was built to catch gamma-ray bursts, but we can use its speed to catch supernovae and now stellar flares," said Swift Project Scientist Neil Gehrels of NASA Goddard. "We can't predict when a flare will happen, but Swift can react quickly once it senses an event.

Swift catches Stellar bursts & giant flares from NASA 06 Nov 2006

Science Daily release:
A Leading Edge
Camera For Molecules

Researchers at the Max Planck Institute for Nuclear Physics in Heidelberg have visualised vibration and rotation in the nuclei of a hydrogen molecule as a quantum mechanical wave packet.

What is more, this has been achieved on an extremely short spatio-temporal scale. They "photographed" the molecule using intensive, ultrashort laser pulses at different points in time and compiled a film from the separate images. This allowed them to visualise the quantum mechanical wave pattern of the vibrating and rotating molecule (Physical Review Letters, Online-Edition, November 6, 2006).

Cameras and light microscopes are not viable options when photographing molecules: a hydrogen molecule is around 5,000 times smaller than the wavelength of visible light and it is therefore not possible to create an optical image of these molecules. Instead, for some time Max Planck researchers have been using pump-probe technology to make high-resolution and ultrahigh-speed images. The molecules are first "bumped" with a "pump" laser pulse and then after a specific time measured with a "probe" laser pulse.
Molecular Photography by JoAnne Hewett @ Cosmic Variance
Double-eyed vortex at Venus' South Pole from ESA 09 Nov 2006
Lisa Randall on Xtra dimensions by Sabine Hossenfelder 09 Nov 2006

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Thursday, November 09, 2006


Orion Nebula NASA, ESA, M. Robberto
(Space Telescope Science Institute/ESA) and the Hubble Space Telescope Orion Treasury Project Team ENLARGE Image

Originally, the word "nebula" referred to almost any extended astronomical object (other than planets and comets). The word "nebula" comes from the Greek word for "cloud." Before astronomers knew that galaxies were distant collections of stars, galaxies were also called nebulae because of their fuzzy appearance. Today, we reserve the word nebula for extended objects consisting mostly of gas and dust.

Nebulae come in many shapes and sizes, and form in many ways. In some nebulae, stars form out of large clouds of gas and dust; once some stars have formed inside the cloud, their light illuminates the cloud, making it visible to us. These star formation regions are sites of emission and reflection nebulae, like the famous Orion Nebula shown in the picture above.

Emission nebulae are clouds of high temperature gas. The atoms in the cloud are energized by ultraviolet light from a nearby star and emit radiation as they fall back into lower energy states (neon lights glow in much the same way). Emission nebulae are usually red, because hydrogen, the most common gas in the universe, most commonly emits red light. Reflection nebulae are clouds of dust that simply reflect the light of a nearby star or stars. Reflection nebulae are usually blue, because blue light scatters more easily. Emission and reflection nebulae are often seen together and are sometimes both referred to as diffuse nebulae. In some nebulae, the star formation regions are so dense and thick that light cannot get through. Not surprisingly, these are called dark nebulae.

Another type of nebula, called a planetary nebula, results from the death of a star. When a star has burned through so much material that it can no longer sustain its own fusion reactions, the star's gravity causes it to collapse. As the star collapses, its interior heats up. The heating of the interior produces a stellar wind that lasts for a few thousand years and blows away the outer layers of the star. When the outer layers have blown away, the remaining core remnant heats the gases, which are now far from the star, and causes them to glow. The resulting "planetary nebulae" (so named because they look like gas giant planets through a telescope) are shells of glowing gas that surround a small core. Astronomers estimate that our galaxy contains about 10,000 planetary nebulae. Planetary nebulae are a common part of the normal stellar life cycle, but they are short-lived, lasting only about 25,000 years.

The life of a star whose mass is greater than 1.4 times the mass of the Sun ends more violently, and leaves behind a different type of nebula called a supernova remnant. When such a star runs out of fuel and collapses, an enormous shock wave sweeps through the star at high speed, blasting away various layers and leaving behind a core called a neutron star and an expanding shell of matter known as a supernova remnant.

A supernova's shock wave is much more violent than the stellar wind that marks the end of a low mass star.

Near the core of the remnant, electrons emit radiation called "synchrotron radiation" as they spiral toward the neutron star at speeds close to the speed of light. The ultraviolet portion of this radiation can strip electrons off, or "ionize" the outer filaments of the nebula, causing them to glow. In addition, the ejected matter sweeps up surrounding gas and dust as it expands, producing a shock wave that excites and ionizes the gas in the supernova remnant nebula, which is at low density but extremely hot (up to 1,000,000° K!). The most famous supernova remnant is the Crab Nebula in Taurus (M1). The light of the inner core is from synchrotron radiation, while the outer regions glow in many colors from emission of many gases, including red for hydrogen.
Spitzer & Hubble view Orion's Trapezium from Universe Today
Famous Quotes For take thy balance if thou be so wise
And weigh the wind that under heaven doth blow;
Or weigh the light that in the east doth rise;
Or weigh the thought that from man's mind doth flow. Voltaire


Tuesday, November 07, 2006

ESA on Climate Change


The United Nations annual summit on climate change
this week in Nairobi, Kenya, seeks to negotiate a successor to the Kyoto Protocol strategy, which becomes obsolete in 2012, to restrict emissions of heat-trapping gases that drive climate change. ESA joins the activities to share results of its satellite-based Kyoto-supporting services.

Around 25 billion tonnes of extra carbon dioxide is released into the atmosphere annually by human activities, mainly through wildfires, land clearance and the burning of fossil fuels. The total amount of carbon dioxide in the atmosphere has increased by a quarter since the start of the Industrial Revolution 150 years ago.

Carbon-storing forests need mapping for the Kyoto Protocol to work In addition to reducing greenhouse emissions to clear the air of excess carbon dioxide, plant growth absorbs carbon from the atmosphere, so the Protocol includes a mechanism for signatories to offset emissions against increases in the stock of carbon stored in vegetation, especially forests.

What the Protocol requires for such offsetting to take place is annual reporting of land use changes – especially afforestation, reforestation and deforestation (ARD) - associated with shifts in the terrestrial carbon stock, to be carried out at the national level.

ESA has a long-standing commitment to extend the use of satellite data beyond science into operational applications, and in particular to strengthen the effectiveness of international conventions. To this end, a project called GSE Forest Monitoring (GSE-FM), which began in February 2003, integrates the most relevant and recent scientific research and monitoring practices with the latest analytical tools and information technologies aimed at detecting changes in forest area and density in order to establish baselines and projections and estimate averted emissions.

Satellite data enable forecasts for offshore industry
Renewable energy has limitless resources, but harnessing its full potential requires careful management of the fluctuations in the energy source. Earth Observation (EO) from space can assist with timely information on available resources such as met-ocean conditions, solar radiation and snow water content as well as environmental factors affecting the yield such as weather conditions, land cover and surface roughness.

The ability of satellites to deliver synoptic information (providing spatial variability) and long-term time series from the archive (providing temporal variability) make them particularly useful to optimise energy production and complement traditional in-situ measurements, which are costly and provide only local information.

more from ESA at UN Summit on Climate Change 6th Nov 2006
Aeronautics Engineers Design Silent, Eco-friendly Plane

MIT and Cambridge University researchers unveiled the conceptual design for a silent, environmentally friendly passenger plane at a press conference Monday, Nov. 6, at the Royal Aeronautical Society in London.

Public concern about noise is a major constraint on expansion of aircraft operations. The 'silent aircraft' can help address this concern and thus aid in meeting the increasing passenger demand for air transport.

The project aims to develop aircraft by 2030.
The conceptual design addresses both the engines and the structure, or airframe, of a plane. Half of the noise from a landing plane comes from the airframe.

Other key features of the design include:
[] An overall shape that integrates body and wings into a "single" flying wing. As a result, both the body and wings provide lift, allowing a slower approach and takeoff, which would reduce noise. The shape also improves fuel efficiency.
[] The elimination of the flaps, or hinged rear sections on each wing. These are a major source of airframe noise when a plane is taking off and landing.
[] Engines embedded in the aircraft with air intakes on top of the plane rather than underneath each wing. This screens much of the noise from the ground.
[] A variable-size jet nozzle that allows slower jet propulsion during takeoff and landing but efficient cruising at higher speeds.

more from Science Daily releases 7th november 2006
Famous Quotes
Winners never quit and quitters never win.
Vince Lombardi

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Monday, November 06, 2006

Light Continues to Echo

Light Continues
To Echo Three Years
After Stellar Outburst

ACS image of V838 Mon.
Credit: NASA, ESA, and
The Hubble Heritage Team

The Hubble Space Telescope's latest image of the star V838 Monocerotis (V838 Mon) reveals dramatic changes in the illumination of surrounding dusty cloud structures. The effect, called a light echo, has been unveiling never-before-seen dust patterns ever since the star suddenly brightened for several weeks in early 2002.

The illumination of interstellar dust comes from the red supergiant star at the middle of the image, which gave off a pulse of light three years ago, somewhat similar to setting off a flashbulb in a darkened room. The dust surrounding V838 Mon may have been ejected from the star during a previous explosion, similar to the 2002 event.

The echoing of light through space is similar to the echoing of sound through air. As light from the stellar explosion continues to propagate outwards, different parts of the surrounding dust are illuminated, just as a sound echo bounces off of objects near the source, and later, objects further from the source. Eventually, when light from the back side of the nebula begins to arrive, the light echo will give the illusion of contracting, and finally it will disappear.

V838 Mon is located about 20 000 light-years away from Earth in the direction of the constellation Monoceros, placing the star at the outer edge of our Milky Way galaxy. The Hubble telescope has imaged V838 Mon and its light echo several times since the star's outburst. Each time Hubble observes the event, different thin sections of the dust are seen as the pulse of illumination continues to expand away from the star at the speed of light, producing a constantly changing appearance. During the outburst event whose light reached Earth in 2002, the normally faint star suddenly brightened, becoming 600 000 times more luminous than our Sun.

The new image of V838 Mon, taken with Hubble's Advanced Camera for Surveys, was prepared from images obtained through filters that isolate blue, green, and infrared light. These images have been combined to produce a full-colour picture that approximates the true colours of the light echo and the very red star near the centre.

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
Source: European Space Agency
V838 Monos revisited February 6, 2005
Deja-Vu How to be in two places at Once? by Plato
Understanding the Tonal Sound & colour by Plato

Famous Quotes
Education's purpose is to replace an empty mind with an open one.
Malcolm Forbes

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Saturday, November 04, 2006

Sheer Majestic Energy

Picture courtesy of netkerveros "Lost in Translation"

Swimming across the ocean
mighty in size and strength
pleasures simple and plain
the Seven Seas My domain

From this one medium to the next
Move fast & flow like light and text
emerging from the deep to kiss the Sun
is what most of all I like to do best

Wishing you all a magical weekend I invite you to visit:

Pictures of the hunter pace & other events from sandypik
Short poetry and images of space from First Light Machine
"I think there is still this far reaching philosophical question about what really started time? If nothing existed then how could we assume anything could arise from it?"
Back to the beginning of Time from Plato
Famous Quotes
I have never been hurt by what I have not said. Calvin Coolidge

Friday, November 03, 2006

Cosmic Bubble

Image courtesy of NRAO/AUI and Jayanne English (U. Manitoba)
& Jeroen Stil, supported by Russ Taylor (U. Calgary); NRAO/AUI & MSX

A Majestic Gas Shell Revealed by the VLA.
What appears to be the hole of an elongated smoke ring in this National Radio Astronomy Observatory image really is an enormous, nearly empty, bubble blown into the dusty, gas disk of our Milky Way Galaxy.

Such interstellar bubbles are sculpted by the force of the wind and radiation from typically a few dozen hot, massive stars along with the explosive impact of dying stars which are called supernovae. The force sweeps up the disk's gas that is in its path, creating a gas shell surrounding a bubble.

The neighbourhood of our own solar system resides in such a cavity. However the shell in this image, catalogued (using its coordinates) as galactic shell GS 62.1+0.2-18, is located at a distance of 30,000 light years from Earth, and measures 1,100 by 520 light years. Despite its distance, this "smoke ring" appears so large on the sky that the apparent width of the full moon would fit eight times inside it.

The bright yellowish-orange dots scattered across this image are clusters of young, massive stars surrounded by hot gas and are called nebulae. Astronomers from the International/VLA Galactic Plane Survey have determined that none of these clusters harbor the stars that blew the giant shell since none of the clusters are at the same distance as the shell.

Indeed they all are located closer to the Earth than the shell is.

Probably, the stars that blew GS 62.1+0.2-18's hole perished as supernova explosions. This image shows only a small part of a survey which uses both the Very Large Array and the Green Bank Telescopes to trace, in detail, the cool gas in our Galaxy. This gas has been coloured purple, blue and green in this image.

In order to show the locations of star clusters, the image of gas was overlaid with 2 additional images. The one of radio emission associated with regions of hot gas was coloured orange, while heated dust, imaged in infrared by the Midcourse Space Experiment satellite, was coloured red.

Cosmic Bubble Image Wins NRAO Contest
This study is published by VGPS investigators in the Astronomical Journal,
Volume 132, number 3, page 1158.
Investigator(s): J. M. Stil, A. R. Taylor, J. M. Dickey, D. W. Kavars, P. G. Martin, T. A. Rothwell, A. I. Boothroyd, Felix J. Lockman, and N. M. McClure-Griffiths


VLA Discovers
Giant Rings
Galaxy Cluster

Astronomers using the National Science Foundation's Very Large Array (VLA) radio telescope have discovered giant, ring-like structures around a cluster of galaxies. The discovery provides tantalizing new information about how such galaxy clusters are assembled, about magnetic fields in the vast spaces between galaxy clusters, and possibly about the origin of cosmic rays.

These giant, radio-emitting rings probably are the result of shock waves caused by violent collisions of smaller groups of galaxies within the cluster

The newly-discovered ring segments, some 6 million light-years across, surround a galaxy cluster called Abell 3376, more than 600 million light-years from Earth. They were revealed because fast-moving electrons emitted radio waves as they spiraled around magnetic field lines in intergalactic space.

Read more NRAO Ring Cluster release 03 Nov 2006
Understanding the Tonal by Plato
Bursting bubbles of new universes by Plato
Super-supermassive Black-hole from Universe Today
Almost famous Quote: “It’s certainly true that we don’t yet know whether the universe is eternal or whether it had a beginning, and we certainly don’t understand the details of its origin.” “The truth is, we just don’t know. I’m guessing eternal, but we just don’t know.”
Sean Carroll @ Cosmic Variance
Famous Quotes
Always remember that you are absolutely unique.
Just like everyone else. Margaret Mead

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Wednesday, November 01, 2006

Star formation at work

AKARI's Infrared Camera (IRC), provides a close-up view of part of the Large Magellanic Cloud.

This false-colour composite image was taken by the AKARI satellite in near- and mid-infrared wavelengths (3, 7 and 11 microns), and shows a portion of the Large Magellanic Cloud.

This galaxy, a place of intense star formation, was observed by AKARI during its whole-sky survey and, for this image, during detailed observations.

This image shows many old stars (visible as white dots) in addition to the interstellar clouds. It enables astronomers to study the way stars recycle their constituent gases and return them to the interstellar medium at the end of their lives.

These and new data obtained by AKARI will unlock the secrets of how both the Large Magellanic Cloud and our own Galaxy have formed and evolved to their current state.

AKARI's Far-infrared view of
the Large Magellanic Cloud
The Large Magellanic Cloud is a neighbouring galaxy to the Milky Way, the galaxy to which our Solar System belongs. It is located extremely close by astronomical standards, at a distance of 160 000 light years and it contains about 10 thousand million stars, about one tenth of our Galaxy's stellar population.

The image is a far-infrared (60, 90 and 140 microns) view obtained by the Far-Infrared Surveyor (FIS) instrument on board AKARI. It reveals the distribution of interstellar matter – dust and gas – over the entire galaxy. Dust grains in these interstellar clouds are heated by the light from newly born stars, and subsequently re-radiate this energy in the form of infrared light. So, the infrared emission indicates that many stars are currently being formed. Such copious star formation activity across a whole galaxy is called a 'star burst'.

The nature of the Large Magellanic Cloud is further revealed by the contrasting distribution of the interstellar matter and the stars. The interstellar matter forms a disk-like structure whilst the stars are located in the 'spindle' shape in the lower half of the image. This shows that the two components are clearly displaced from one another.

Astronomers believe that the observed star formation and the displacement of these two components in the Large Magellanic Cloud were both triggered by the gravitational force generated by our own Galaxy, the Milky Way.

The bright region in the bottom-left of the image is known as the 'Tarantula Nebula'. It is a very productive factory of stars.

The Large Magellanic
Cloud in visible light
Click to ENLARGE

ESA International
1st November 2006
Press Release
more from PPARC
Micrometre: a measurement for wavelengths of infrared radiation.
Some people in astronomy and the semiconductor business use the old name micron
Distances shorter than 1 µm 1 micrometre (micron)
Items with lengths between 1-10 µm (microns)
1.55 µm — wavelength of
light used in optical fibre
6 µm —
anthrax spore
6-8 µm — diameter of a human
red blood cell
7 µm — diameter of the
nucleus of typical eukaryotic cell
7 µm — width of strand of
spider web
1-10 µm — diameter of typical
about 10 µm — size of a
fog, mist or cloud water droplet
Distances longer than 10 µm
Science Daily: Large & small stars in Harmonious coexistence
Famous Quotes Even though your kids will consistently
do the exact opposite of what you're telling them to do,
you have to keep loving them just as much. Bill Cosby

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