Tuesday, October 31, 2006

Closer to the Edge

Click to view animation
(2.6 Mb -- no audio).

Supermassive black holes are a prime target for Suzaku. These are voids in the center of most galaxies containing the mass of millions to billions of suns, all confined within a region about the size of our solar system. The black hole itself emits no light, but the process of accreting matter causes the entire region to be extremely bright in all wavelengths. Close to the edge of a black hole, X-rays are the dominant wavelength. Suzaku is sensitive to the X-ray energies emitted close to supermassive black holes, such as quasars.

The observations include clocking the speed of a black hole's spin rate and measuring the angle at which matter pours into the void, as well as evidence for a wall of X-ray light pulled back and flattened by gravity.

The findings rely on a special feature in the light emitted close to the black hole, called the "broad iron K line,” once doubted by some scientists because of poor resolution in earlier observations, now unambiguously revealed as a true measure of a black hole's crushing gravitational force. This technique can be exploited in future X-ray missions

Click to view animation
(3.6 Mb -- no audio).

Zoom into the center of a spiral galaxy to reveal a black hole. Cutaway of accretion disks reveals inside of the black hole. The chaotic black hole activity is hard to discern. >From our perspective, all activity is enshrouded in dust and gas in a region that's only a pinpoint a few light-years across in the center of a galaxy hundreds of thousands of light-years across, all typically hundreds of millions of light-years from Earth. The Suzaku satellite is sensitive to key X-ray energies that enable scientists to discern properties of the black hole. Some X-rays are emitted at the edge of the black hole; others are reflected off of dust clouds several light-years away. Suzaku provides the most complete picture of this black hole activity, and when combined with optical and radio observations, even more can be learned

Click to view animation
(2.5 Mb -- no audio).

Shown here is the tale of two hot blobs of matter moving around a black hole. Scientists can trace the movement through spectral analysis. The broad iron K line is the signature of hot iron plasma in the presence of strong gravity. In the absence of gravity, hot iron will produce a clean spike on a spectrograph at 6.4 kiloelectron volts. Because a black hole's gravity will tug at light itself, this iron line, when emitted near a black hole, is stretched, or broadened. The result is something that resembles the outline of a mountain range instead of a single spike. And yet the spectral signature gets even more complicated: As matter moves around a black hole, moving away and then closer to us, the spectral line undergoes a Doppler shift. The X-rays increase in energy when emitted from mater moving towards us (called a blue-shift) and decrease in energy when moving away from us (called a red-shift).

Click to view animation
(4.3 Mb -- no audio).

Scientists can discern whether a black hole is spinning or not by studying the matter and energy around the black hole. If the black hole is spinning, matter can orbit more tightly. This is called the "innermost stable circular orbit," the closest you can get to a black hole without falling in. The faster the black hole spins, the tighter the orbit. Because gravity is stronger closer to the black hole, light is stretched more. So a spinning black hole has a spectrum that's "broader" --- a reflection of iron gas that usually emits X-rays at 6.4 kiloelectron volts but instead is broadened or stretched to lower energies. How low and how broad is a reflection of how fast the black hole is spinning and how close matter gets to it.
NASA news 5th Oct 2006 Scientists Nudge Closer to the Edge of a Black Hole
Spooky Nebula from Astronomy PIC OF THE DAY
Finiteness of supergravity theories by Lubos Motl
Famous Quotes
Knowledge comes, but wisdom lingers.
Alfred Lord Tennyson

Monday, October 30, 2006

Galactic Snake

Where Galactic snakes live High Resolution Image

Snake on a Galactic Plane!
Animated Galactic Snake
Something scary appears to be slithering across the plane of our Milky Way galaxy in this new Halloween image from NASA's Spitzer Space Telescope. The snake-like object is actually the core of a thick, sooty cloud large enough to swallow dozens of solar systems. In fact, astronomers say its "belly" may be harboring beastly stars in the process of forming.

This infrared image from NASA's Spitzer Space Telescope shows what astronomers are referring to as a "snake" (upper left) and its surrounding stormy environment.

The galactic creepy crawler to the right of the snake is another thick cloud core, in which additional burgeoning massive stars might be lurking. The colorful regions below the two cloud cores are less dense cloud material, in which dust has been heated by starlight and glows with infrared light. Yellow and orange dots throughout the image are monstrous developing stars; the red star on the "belly" of the snake is 20 to 50 times as massive as our sun. The blue dots are foreground stars.

The red ball at the bottom left is a "supernova remnant," the remains of massive star that died in a fiery blast. Astronomers speculate that radiation and winds from the star before it died, in addition to a shock wave created when it exploded, might have played a role in creating the snake.

Spitzer was able to spot the two black cloud cores using its heat-seeking infrared vision. The objects are hiding in the dusty plane of our Milky Way galaxy, invisible to optical telescopes. Because their heat, or infrared light, can sneak through the dust, they first showed up in infrared images from past missions. The cloud cores are so thick with dust that if you were to somehow transport yourself into the middle of them, you would see nothing but black, not even a star in the sky. Now, that's spooky!

Spitzer's new view of the region provides the best look yet at the massive embryonic stars hiding inside the snake. Astronomers say these observations will ultimately help them better understand how massive stars form. By studying the clustering and range of masses of the stellar embryos, they hope to determine if the stars were born in the same way that our low-mass sun was formed -- out of a collapsing cloud of gas and dust -- or by another mechanism in which the environment plays a larger role.

The snake is located about 11,000 light-years away in the constellation Sagittarius. This false-color image is a composite of infrared data taken by Spitzer's infrared array camera and multiband imaging photometer. Blue represents 3.6-micron light; green shows light of 8 microns; and red is 24-micron light.
NASA news 27th October 2006
Light Echo from Star V838 Monocerotis

These are the most recent NASA Hubble Space Telescope views of an unusual phenomenon in space called a light echo. Light from a star that erupted nearly five years ago continues propagating outward through a cloud of dust surrounding the star. The light reflects or "echoes" off the dust and then travels to Earth.

Because of the extra distance the scattered light travels, it reaches the Earth long after the light from the stellar outburst itself. Therefore, a light echo is an analog of a sound echo produced, for example, when sound from an Alpine yodeler echoes off of the surrounding mountainsides.

The echo comes from the unusual variable star V838 Monocerotis (V838 Mon), located 20,000 light-years away on the periphery of our Galaxy. In early 2002, V838 Mon increased in brightness temporarily to become 600,000 times brighter than our Sun. The reason for the eruption is still unclear.

Hubble has been observing the V838 Mon light echo since 2002. Each new observation of the light echo reveals a new and unique "thin-section" through the interstellar dust around the star. The new images of the light echo were taken with Hubble's Advanced Camera for Surveys in November 2005 (left) and September 2006 (right). Particularly noticeable in the images are numerous whorls and eddies in the interstellar dust, which are possibly produced by effects of magnetic fields.
hubblesite 26th Oct 2006 News Release Number: STScI-2006-50
The Soul Nebula by Frank Barnes @ Universe Today
Lighting Up a Dead Star's Layers @ NASA news release 26 Oct 2006
Gamma Rays from edge of supermassive black-hole from Max Planck Society
The Higgs boson and memory by Plato
Bursting bubbles of new Universes by Plato
Probing the perfect liquid by Plato

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Saturday, October 28, 2006

BlackPearl on wet Sand

Black Pearl on wet sand courtesy of Talithah's black beauties

The seemingly eternal paradox of living & life
lost somewhere between the suffering & strife

Everyday so much joy to be found, so much delight
from the morning sun to the brightest star at night

One feels the wind rushing by, one feels the thrills
one seeks life's pleasures, bliss with its many frills

As I run, and run, and run, it is towards you I race
such beauty, such joy, such sublime finery & grace
warmest breath, passion wild, to cherish and embrace

Wishing you all a Magical weekend, as ever
I invite you to visit more beautiful horses from sandypik
to vote for me in the captions competion @ belleofthebrawl
to look at beautiful paintings & artwork from mischiefangel
and amazing art & animals from katie @ montanagypsy
View the Magic of Tokyo & HG's from Karaoke Queen
Famous Quotes Talent does what it can;
genius does what it must. Edward Bulwer-Lytton
Famous Quotes Success is getting what you want.
Happiness is wanting what you get. Dale Carnegie

Friday, October 27, 2006

Circumstellar Disk

Subaru Telescope ENLARGE Image

The Role of a Circumstellar Disk
A star is born when gas collects within a molecular cloud. The gas is mainly in the form of molecular hydrogen. Because gas has angular momentum, it can't land directly onto the surface of a star. Instead, it forms a thin, disk-like structure around a star, and slowly loses momentum as it orbits the star and so that the star can eventually pull it in. Without such a "circumstellar disk", a star could not collect mass from its birth cloud.

Beyond its function as the gas supply for star formation, a circumstellar disk also provides raw material for planets. Material left over from the star formation gradually stick together, making pebbles and rocks. These amass together to form even larger bodies, such as 100-meter-wide planetesimals. All of this material continues to rotate around the star while it grows into ever-larger bodies. Eventually, if conditions are right, this accretion process produces a rocky planet similar to Earth.

Recent observational studies of circumstellar disks have been taking advantage of the thermal emission and scattered light from the solid material in disks. However, in the early epochs of a disk's existence, these solids only comprise about one percent of the total disk mass. The rest is still in the gas phase, and mainly in molecular form (like carbon monoxide). Looking at a disk and studying its carbon monoxide component rather than its dust grains, means we are looking at the gas disk, which is the main component of the disk.

A circumstellar disk only exists for a short time while its central star is collecting gas from it. To understand how a disk evolves, imagine that the entire lifetime of the star was only a hundred years. The circumstellar disk would only exist from three days to a month before it dissipates altogether. A star has only one chance to form a planetary system during the relatively short life of its circumstellar disk. If the ionizing radiation from the star prevents the dust disk from accreting into planets before it dissipates, then the star's chance to become the center of a solar system is lost forever. When and how a disk dissipates, therefore, has direct consequences for the possibility of planetary formation.
Photo-evaporation of a Disk
Top: An image of HD 141569A from HST (Clampin et al. 2003 AJ,126, 385). The inner 200AU of the disk is masked.
Middle: The spectral data combined into a single image showing the spatial distribution of gas and its velocity. The horizontal axis is the distance from the star and the vertical axis is the velocity.
Bottom: A close up of the middle panel. The combination of a high-resolution spectrograph with adaptive optics technology allows access to the inner most part of the disk hidden behind the mask in the HST data.
The size of the central opening in the disk suggests that photo-evaporation is responsible for its clearing. It is also possible that one or more planets could be sweeping up material as they orbit around the star. There is, as yet, no evidence for such planets.

These results will be published in
the Astrophysical Journal in late 2006 or early 2007.
Subaru Telescope Press release 23rd October 2006
Inner Rim of A Molecular Disk Spatially Resolved in Infrared CO Emission Lines.
The Research Group: Miwa Goto (Max Planck Institute for Astronomy, Heidelberg, Germany) Tomonori Usuda (Subaru Telescope, NAOJ) C. P Dullemong (MPIA) Th. Henning (MPIA) H. Linz (MPIA) B. Stecklum (MPIA) Hiroshi Suto (NAOJ)
Probing the perfect liquid &
The string saga of star shine by Plato
Dark Matter & Chocolate by Sabine @ BackReaction
Fermilab discovers exotic relatives of Protons & Neutrons
Famous Quotes
It is human nature to think wisely and act in an absurd fashion.
Anatole France

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Wednesday, October 25, 2006

The Antennae Galaxies

STScI-PRC2006-46 ::: ENLARGE Image ::: Hubblesite ZOOM

The Antennae Galaxies/NGC 4038-4039
This new NASA Hubble Space Telescope image of the Antennae galaxies is the sharpest yet of this merging pair of galaxies. During the course of this collision billions of stars will be formed. The brightest and most compact of these star birth regions are called super star clusters.

The two galaxies started to interact several hundred million years ago, making the Antenae galaxies one of the nearest and youngest examples of a pair of colliding galaxies. Nearly half of the faint objects in the Antennae image are young clusters containing tens of thousands of stars. The orange blobs to the left and right of the image centre are the cores of the original galaxies and consist mainly of old stars criss-crossed by filaments of dust. The two galaxies are dotted with brilliant blue star forming regions surrounded by glowing hydrogen gas, appearing pink in the image.

The new image allows astronomers to better distinguish between the stars and super star clusters created in the collision of two spiral galaxies. By age dating the clusters in the image, astronomers find that only about 10 percent of the newly formed super star clusters in the Antennae will survive beyond the first 10 million years. The vast majority of the super star clusters formed during this interaction will disperse, with the individual stars becoming part of the smooth background of the galaxy. It is however believed that about a hundred of the most massive clusters will survive to form regular globular clusters, similar to the globular clusters found in our own Milky Way galaxy.

The Antennae galaxies take their name from the long antenna-like "arms" extending far out from the nuclei of the two galaxies, best seen by ground-based telescopes. These "tidal tails" were formed during the initial encounter of the galaxies some 200 to 300 million years ago. They give us a preview of what may happen when our Milky Way galaxy will collide with the neighboring Andromeda galaxy in several billion years.

Credit: NASA, ESA, and
the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration
Acknowledgment: B. Whitmore (Space Telescope Science Institute)

The Big Bang dialogues

1) A Gravitational collapse of what?
2) Does gravity precede the Big Bang
3) Do we now favour Smolin's: "this Universe came into being thru a pin prick or small blackhole in another universe?"
4) A Big Bang theory with no collision? then how can the collider presume to take us back to the Big Bang
5) Ok - so no collision, but what is it exploded that contained the seed for all the matter we see in the universe ...
6) This logic or thinking would favour Smolin's theory that we are indeed a blackhole within (or from) another blackhole, like a seed contains the DNA to turn it into a tree -in the right environment- and sperm contains the DNA to turn it into another different human -in the right nucleus or egg-
Incidentally if you can have dolly the cloned sheep you can have replica (cloned) blackholes - but what happened to dolly the sheep? didn't last as long

If we detect radiation from North Korea, Pakistan and India - we have proof of nuclear tests or nuclear explosions. But if we didn't have old film or footage (recorded images) of Hiroshima and Nagasaki how could we presume to know what was there before 1945. Would we then trace the radiation back to the atomic explosions and conclude a big bang took place - and Japan appeared out of nowhere???
Is Ground zero anything other than a 'blackhole' in spacetime.

The string saga of star shine by Plato
Dark Matter & Chocolate by Sabine @ BackReaction
Famous Quotes Millions saw the apple fall,
but Newton was the one who asked why. Bernard Baruch
Newton tried to understand & explain why apples fall. Quasar9

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Tuesday, October 24, 2006

Spitzer's Cosmic Ball

NASA/JPL-Caltech/D. Elmegreen (Vassar)

Cosmic Ball
Something appears to be peering through a shiny red mask, in this new false-colored image from NASA's Spitzer Space Telescope. The mysterious blue eyes are actually starlight from the cores of two merging galaxies, called NGC 2207 and IC 2163. The mask is the galaxies' dusty spiral arms.

The string saga of star shine by Plato
Dark Matter & Chocolate by Sabine @ BackReaction

Symmetry in Supergravity: Double Pupil by cyberchaos

Magnetic Dipole Radiation from MIT education

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Monday, October 23, 2006

Quote of the Day

Famous Quotes
Only the educated are free.

Restless Universe
Restless Universe thumbsnap


Hi Plato,
whilst I have no problem following the process of thought in Science: Physics, Chemistry, Biology & Maths

I am still of the opinion that Science and knowledge only reveal what is possible: Mobile phone communications will not work unless we follow the processes by which they work. Computing & The Internet does not work, and does not work faster unless we follow 'defined' steps.

Of course there are many programmes, many computer languages - and the hardest of all is the 'perfect' or accurate computer (maths) translator among the many human languages.

Theories on the other hand are not necessarily fact or truth.
The theory of the big bang is a theory - it does not tell us the origin of the Universe or the actual cause of it, any more accurately than the Koran
The theory of Evolution does not tell us the origin of biological life, and even less the origin of human life, certainly no more clearly than the Bible or the Koran
And neither theory tells us of the origin of Mind - and only ignorant man would presume that Mind is something peculiar only to human 'beings'

We can only interpret the Physical world by observation and theory, but the eye and mind can often be deceived by men's lies, or even by a trick of the light.
Radius of the little circle by Plato
into the infrared by Louise Riofrio
Stirring Things UP by Louise Riofrio
Celestial Sphere by Louise Riofrio

Saturday, October 21, 2006

Lived Fast Died Young

Image Credit: Nicolle Rager Fuller/NSF physorg: newman - gamma_h_star

Stars shine by burning hydrogen. The process is called nuclear fusion. Hydrogen burning produces helium "ash." As the star runs out of hydrogen (and nears the end of its life), it begins burning helium. The ashes of helium burning, such as carbon and oxygen, also get burned. The end result of this fusion is iron. Iron cannot be used for nuclear fuel. Without fuel, the star no longer has the energy to support its weight. The core collapses. If the star is massive enough, the core will collapse into a black hole. The black hole quickly forms jets; and shock waves reverberating through the star ultimately blow apart the outer shells. Gamma-ray bursts are the beacons of star death and black hole birth.

It came from the edge of the visible universe, the most distant explosion ever detected. In this week's issue of Nature, scientists at Penn State University and their U.S. and European colleagues discuss how this explosion, detected on 4 September 2005, was the result of a massive star collapsing into a black hole.

The explosion, called a gamma-ray burst, comes from an era soon after stars and galaxies first formed, about 500 million to 1 billion years after the Big Bang. The universe is now 13.7 billion years old, so the September burst serves as a probe to study the conditions of the early universe.

"This was a massive star that lived fast and died young," said David Burrows, senior scientist and professor of astronomy and astrophysics at Penn State, a co-author on one of the three reports about this explosion published this week in Nature. "This star was probably quite different from the kind we see today, the type that only could have existed in the early universe.
Full article Physorg 8th March 2006

Observations involve theory Central-theme-is-Sun
Observations involve theory doppelganger-favors-oscillate
National Trust Autumn Colours
Famous Quotes
Winning is not everything, but wanting to win is. Vince Lombardi

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Thursday, October 19, 2006

Paradoxical Universes

A Creationist Universe gives birth to atheist Minds


An Evolutionary Universe creates theist Minds

Famous Quotes
The danger of the past was that men became slaves.
The danger of the future is that man may become robots.
Erich Fromm

What you choose to be a slave to - Is proof of free will
What you choose to believe -
will make you a slave, or make you free

Tuesday, October 17, 2006

Stellar Nursery

Selection of fave pics Thanks to: JoAnne, Amara and
other contributors and visitors to: cosmic variance fav pics

More Celestial images from
cool cosmos
noao galaxies
Orion Nebula + zoom
Crab Nebula + zoom
M51 large by robert gendler

NASA under Contract NAS5-26555.
Unless otherwise specifically stated, no claim to copyright is being asserted by STScI and it may be freely used as in the public domain in accordance with NASA's contract.

Extracting Beauty from Chaos by Plato
The Milky Way's Black Hole?? by Plato
Famous Quotes
Thinking is one thing no one has ever been able to tax.
Charles Kettering

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Saturday, October 14, 2006

Team effort

Free Image hosting by ImageSnap
Team-effort by Sandy

Wendy and Promise
taking a break from grazing
to scratch each others back.

For beautiful horses and more about
the Thoroughbred Foundation visit Life with Horses
Famous Quotes
Never doubt that a small group of thoughtful,
committed citizens can change the world;
indeed, it's the only thing that ever has. Margaret Mead

Tuesday, October 10, 2006

Active Galaxies

Artist's concept of an active galaxy.
Credit: Aurore Simonnet
Sonoma State University

Nearly every massive galaxy seems to have a supermassive black hole, but only a few percent appear to be active. Our galaxy's central black hole is dormant, and this and similar black holes are not included in the Swift satellite census. All black holes were likely once active, and why some remain active and others are dormant in the modern, local universe is a mystery.

The all-sky survey contains more than 200 supermassive black holes called Active Galactic Nuclei, or AGN, and provides a definitive census of black hole activity in the local universe. The team uncovered many new black holes that were previously missed, even in well-studied galaxies, and other surprises as well.

AGN have a mass of millions to billions of suns, which are confined within a region about the size of our solar system. The term "active" refers to the process of actively pulling in gas and whole stars and generating copious amounts of energy from a tiny galactic core in the process. Examples include quasars and Seyfert galaxies.

The Swift satellite was built primarily to study gamma-ray bursts. During waiting times between bursts, Swift's Burst Alert Telescope, which is sensitive to the highest-energy X-rays, scans the sky. AGN generate X-rays as well as many other forms of light. Many AGN, however, are hidden behind dust and gas, which block lower-energy light, such as visible light. Because higher-energy X-rays are so penetrating, Swift can detect AGN missed by other surveys, allowing for an unbiased count.

For more visit: NASA Performs Headcount of Local Black Holes
Chandra Reviews Black hole Musical

A gigantic sonic boom generated by a supermassive black hole has been found with NASA's Chandra X-ray Observatory, along with evidence for a cacophony of deep sound.

This discovery was made by using data from the longest X-ray observation ever of M87, a nearby giant elliptical galaxy. M87 is centrally located in the Virgo cluster of galaxies and is known to harbor one of the Universe's most massive black holes.

Scientists detected loops and rings in the hot, X-ray emitting gas that permeates the cluster and surrounds the galaxy. These loops provide evidence for periodic eruptions that occurred near the supermassive black hole, and that generate changes in pressure, or pressure waves, in the cluster gas that manifested themselves as sound.

"We can tell that many deep and different sounds have been rumbling through this cluster for most of the lifetime of the Universe," said William Forman of the Harvard-Smithsonian Center for Astrophysics (CfA).

The outbursts in M87, which happen every few million years, prevent the huge reservoir of gas in the cluster from cooling and forming many new stars. Without these outbursts and resultant heating, M87 would not be the elliptical galaxy it is today

"If this black hole wasn't making all of this noise, M87 could have been a completely different type of galaxy," said team member Paul Nulsen, also of the CfA, "possibly a huge spiral galaxy about 30 times brighter than the Milky Way."

The outbursts result when material falls toward the black hole. While most of the matter is swallowed, some of it was violently ejected in jets. These jets are launched from regions close to the black hole (neither light nor sound can escape from the black hole itself) and push into the cluster's gas, generating cavities and sound which then propagate outwards.

Chandra's M87 observations also give the strongest evidence to date of a shock wave produced by the supermassive black hole, a clear sign of a powerful explosion. This shock wave appears as a nearly circular ring of high-energy X-rays that is 85,000 light years in diameter and centered on the black hole.

For more & animations visit Chandra Reviews Black Hole Musical
more links to NOVA origins by Lubos Motl

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Monday, October 09, 2006

Cosmic Radiation

Cosmic radiation
entering Earth's atmosphere.

An essential role for remote stars in everyday weather on Earth has been revealed by the Danish National Space Center in Copenhagen.

A team at the Danish National Space Center has discovered how cosmic rays from exploding stars can help to make clouds in the atmosphere. The results support the theory that cosmic rays influence Earth's climate.

It is already well-established that when cosmic rays, which are high-speed atomic particles originating in exploded stars far away in the Milky Way, penetrate Earth's atmosphere they produce substantial amounts of ions and release free electrons.
Now, results from the Danish experiment show that the released electrons significantly promote the formation of building blocks for cloud condensation nuclei on which water vapour condenses to make clouds.
Hence, a causal mechanism by which cosmic rays can facilitate the production of clouds in Earth's atmosphere has been experimentally identified for the first time.

The Danish team officially announced their discovery, published by the Royal Society, the British national academy of science.

Read more on the SKY experiment
neutrinos & cosmic particles by Plato
neutrinos for beginners by Sabine Hossenfelder
Explaining Cosmic Rays by Clifford @ Asymptotia
more on Climate Sciences by Stoat @ Scienceblogs
Saturn's Clouds in Silhouette

False colour image
made with data from

Cassini's visual & infrared
mapping spectrometer,
which can image the planet
at 352 different wavelengths
Image credit: NASA/JPL/SSI
Cassini February, 2006
Click to enlarge

False-colour mosaic of Saturn
The strange red colour is the glow of thermal radiation from inside Saturn’s warm interior, which is visible on the night-side of the planet.

The northern hemisphere is brighter because the atmosphere is relatively clear - this reveals the turbulent lower clouds. Cassini took this image when it was 1 million miles from Saturn.

Read the full story @ universetoday
more on Saturn's Rings by Louise Riofrio
mission to Saturn Cassini Huygens NASA
Famous Quotes
Never give in and never give up.
Hubert H. Humphrey

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Saturday, October 07, 2006

Free like The Wind

Haleem by gurrygudfinns Every Day words by Quasar9

Every day I rise, to a blissful new day
Every day I rise, just for fun and to play
Every New day I'm born, again and again
Every New day I'm grateful rain or no rain
Every New day, you can watch me as I train
Every New day, like the wind with flowing mane

For more beautiful horses visit Life with Horses
Almost famous quote: "There is One thing I know for sure,
there are thousands of ways to live life - being happy or being sad"
Wishing you all a mighty fine weekend & light filled day everyday.

Thursday, October 05, 2006

Strange Moonlight

Harvest Moon by javacafe

Not so long ago, before electric lights, farmers relied on moonlight to harvest autumn crops. With everything ripening at once, there was too much work to to do to stop at sundown. A bright full moon—a "Harvest Moon"— allowed work to continue into the night.

The moonlight was welcome, but as any farmer could tell you, it was strange stuff. How so? See for yourself. The Harvest Moon of 2006 rises on October 6th, and if you pay attention, you may notice a few puzzling things:

1. Moonlight steals colour from whatever it touches. Regard a rose. In full moonlight, the flower is brightly lit and even casts a shadow, but the red is gone, replaced by shades of gray. In fact, the whole landscape is that way. It's a bit like seeing the world through an old black and white TV set.

"Moon gardens" turn this 1950s-quality of moonlight to advantage. White or silver flowers that bloom at night are both fragrant and vivid beneath a full moon. Favourites include Four-O'clocks, Moonflower Vines, Angel's Trumpets—but seldom red roses.

2. If you stare at the gray landscape long enough, it turns blue. The best place to see this effect, called the "blueshift" or "Purkinje shift" after the 19th century scientist Johannes Purkinje who first described it, is in the countryside far from artificial lights. As your eyes become maximally dark adapted, the blue appears. Film producers often put a blue filter over the lens when filming night scenes to create a more natural feel, and artists add blue to paintings of nightscapes for the same reason. Yet if you look up at the full moon, it is certainly not blue. Note: Fine ash from volcanoes or forest fires can turn moons blue, but that's another story.

3. Moonlight won't let you read. Open a book beneath the full moon. At first glance, the page seems bright enough. Yet when you try to make out the words, you can't. Moreover, if you stare too long at a word it might fade away. Moonlight not only blurs your vision but also makes a little blind spot. Note: As with all things human, there are exceptions. Some people have extra-sensitive cones or an extra helping of rods that do allow them to read in the brightest moonlight.

This is all very strange. Moonlight, remember, is no more exotic than sunlight reflected from the dusty surface of the moon. The only difference is intensity: Moonlight is about 400,000 times fainter than direct sunlight.

So what do we make of it all? The answer lies in the eye of the beholder. The human retina is responsible.
The retina is like an organic digital camera with two kinds of pixels: rods and cones. Cones allow us to see colours (red roses) and fine details (words in a book), but they only work in bright light. After sunset, the rods take over.

Rods are marvelously sensitive (1000 times more so than cones) and are responsible for our night vision. According to some reports, rods can detect as little as a single photon of light! There's only one drawback: rods are colourblind. Roses at night thus appear gray.

If rods are so sensitive, why can't we use them to read by moonlight? The problem is, rods are almost completely absent from a central patch of retina called the fovea, which the brain uses for reading. The fovea is densely packed with cones, so we can read during the day. At night, however, the fovea becomes a blind spot. The remaining peripheral vision isn't sharp enough to make out individual letters and words.

Finally, we come to the blueshift. Consider this passage from a 2004 issue of the Journal of Vision:

"It should be noted that the perception of blue, or any colour for that matter in a purely moonlit environment is surprising, considering that the light intensity is below the detection threshold for cone cells. Therefore if the cones are not being stimulated how do we perceive the blueness?" --"Modeling Blueshift in Moonlit Scenes using Rod-Cone Interaction" by Saad M. Khan and Sumanta N. Pattanaik, University of Central Florida.

The authors of the study went on to propose a bio-electrical explanation--that signals from rods can spill into adjacent blue-sensitive cones under conditions of full-moon illumination (see the diagram). This would create an illusion of blue. "Unfortunately," they point out, "direct physiological evidence to support or negate the hypothesis is not yet available."
The blueshift is sometimes attributed to the spectral response of rods. Although rods are nominally colour blind, they do not respond equally to all colours: Rods are more sensitive to blue-green photons and less sensitive to red photons. You can see this in your moonlit rose. By day, the red flower dominates the green leaves. At night, the situation is reversed. The green leaves are more vivid than the red flower.

No matter which part of the rose stands out most, however, the ensemble is still gray. This is because the rods have no mechanism for separating colours. Shades of gray are all we get.

Cones are able to separate colours because they come in three varieties: red-sensitive, green-sensitive, and blue-sensitive. The brain can sort out the colour of an object by noting which kind of cone it stimulates most.
Rods, on the other hand, come in one variety only--monochromatic, which brings us back to the mystery of the blue shift. If rods can't separate colours, how does the brain register a blue rather than gray landscape?
Khan and Pattanaik's hypothesis of rod signals "bleeding" into adjacent blue-sensitive cones provides a possible but untested explanation.

Dates and Times: The Moon is full on Oct 7th at 0313 UT
or 11:13 pm EDT on Oct. 6th: Moon phase calendar.
Source science.nasa.gov headlines strangemoonlight 28th Sept 2006
Web Links:
The Eye and Night Vision -- from the USAF Special Report
Webvision -- The organization of the Retina and the Visual System
The Purkinje shift -- (Wikipedia)
Rods and Cones -- (Hyperphysics)
Night Rendering -- a study of moonlight in art and computer graphics
What do dogs see? -- (Journal of Veterinary Medicine)
How Vision Works -- (HowStuffWorks)
The Vision for Space Exploration
Famous Quotes
I not only use all the brains that I have,
but all that I can borrow. Woodrow Wilson

Wednesday, October 04, 2006

Extreme Planets

NASA/JPL-Caltech/R. Hurt (SSC) ENLARGE Image

This artist's concept depicts the pulsar planet system discovered by Aleksander Wolszczan in 1992. Wolszczan used the Arecibo radio telescope in Puerto Rico to find three planets - the first of any kind ever found outside our solar system - circling a pulsar called PSR B1257+12. Pulsars are rapidly rotating neutron stars, which are the collapsed cores of exploded massive stars. They spin and pulse with radiation, much like a lighthouse beacon. Here, the pulsar's twisted magnetic fields are highlighted by the blue glow.

All three pulsar planets are shown in this picture; the farthest two from the pulsar (closest in this view) are about the size of Earth. Radiation from charged pulsar particles would probably rain down on the planets, causing their night skies to light up with auroras similar to our Northern Lights. One such aurora is illustrated on the planet at the bottom of the picture.

Since this landmark discovery, more than 160 extrasolar planets have been observed around stars that are burning nuclear fuel. The planets spotted by Wolszczan are still the only ones around a dead star. They also might be part of a second generation of planets, the first having been destroyed when their star blew up. The Spitzer Space Telescope's discovery of a dusty disk around a pulsar might represent the beginnings of a similarly "reborn" planetary system.

Source sscws1.ipac.caltech.edu 5thApril 2006

NASA/JPL-Caltech/R. Hurt (SSC) ENLARGE Image

Out of the Dust, A Planet is Born
In this artist's conception, a possible newfound planet spins through a clearing in a nearby star's dusty, planet-forming disc. This clearing was detected around the star CoKu Tau 4 by NASA's Spitzer Space Telescope. Astronomers believe that an orbiting massive body, like a planet, may have swept away the star's disc material, leaving a central hole.

The possible planet is theorized to be at least as massive as Jupiter, and may have a similar appearance to what the giant planets in our own solar system looked like billions of years ago. A graceful ring, much like Saturn's, spins high above the planet's cloudy atmosphere. The ring is formed from countless small orbiting particles of dust and ice, leftovers from the initial gravitational collapse that formed the possible giant planet.

If we were to visit a planet like this, we would have a very different view of the universe. The sky, instead of being the familiar dark expanse lit by distant stars, would be dominated by the thick disc of dust that fills this young planetary system. The view looking toward CoKu Tau 4 would be relatively clear, as the dust in the interior of the disc has fallen into the accreting star. A bright band would seem to surround the central star, caused by light scattered back by the dust in the disc. Looking away from CoKu Tau 4, the dusty disc would appear dark, blotting out light from all the stars in the sky except those which lie well above the plane of the disc.

Source sscws1.ipac.caltech.edu 27th May 2004
Famous Quotes
About the time we can make the ends meet,

somebody moves the ends. Herbert Hoover

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Monday, October 02, 2006

Proto-Planet Formation

Watching How Planets Form: Anatomy Of A Planet-forming Disc Around A Star More Massive Than The Sun

Artist's impression of a flared proto-planetary disc, similar to what has been deduced around the 2.5 solar mass star HD 97048. Image courtesy of: European Southern Observatory
With the VISIR instrument on ESO's Very Large Telescope, astronomers have mapped the disc around a star more massive than the Sun. The very extended and flared disc most likely contains enough gas and dust to spawn planets. It appears as a precursor of debris discs such as the one around Vega-like stars and thus provides the rare opportunity to witness the conditions prevailing prior to or during planet formation.

"Planets form in massive, gaseous and dusty proto-planetary discs that surround nascent stars. This process must be rather ubiquitous as more than 200 planets have now been found around stars other than the Sun," said Pierre-Olivier Lagage, from CEA Saclay (France) and leader of the team that carried out the observations. "However, very little is known about these discs, especially those around stars more massive than the Sun. Such stars are much more luminous and could have a large influence on their disc, possibly quickly destroying the inner part."

The astronomers used the VISIR instrument [1] on ESO's Very Large Telescope to map in the infrared the disc surrounding the young star HD 97048. With an age of a few million years [2], HD 97048 belongs to the Chameleon I dark cloud, a stellar nursery 600 light-years away. The star is 40 times more luminous than our Sun and is 2.5 times as massive.

The astronomers could only have achieved such a detailed view due to the high angular resolution offered by an 8-metre size telescope in the infrared, reaching a resolution of 0.33 arcsecond. They discovered a very large disc, at least 12 times more extended than the orbit of the farthest planet in the Solar System, Neptune. The observations suggest the disc to be flared. "This is the first time such a structure, predicted by some theoretical models, is imaged around a massive star," said Lagage.

Such a geometry can only be explained if the disc contains a large amount of gas, in this case, at least as much as 10 times the mass of Jupiter. It should also contain more than 50 Earth masses in dust.
The dust mass derived here is more than thousand times larger than what is observed in debris discs and Kuiper belt-like structures found around older, 'Vega-like' stars, such as Beta Pictoris, Vega, Fomalhaut and HR 4796. The dust around these stars is thought to be produced by collisions of larger bodies. The dust mass observed around HD 97048 is similar to the mass invoked for the (undetected) parent bodies in the more evolved systems. HD 97048's disc is thus most likely a precursor of debris discs observed around older stars.

"From the structure of the disc, we infer that planetary embryos may be present in the inner part of the disc," said Lagage. "We are planning follow-up observations at higher angular resolution with ESO's VLT interferometer in order to probe these regions."

The scientists report their discovery in the 28 September issue of Science Express, the rapid online publication service of the journal Science: "Anatomy of a flaring proto-planetary disc around a young intermediate-mass star", by P.-O. Lagage et al.
The team is composed of Pierre-Olivier Lagage, Coralie Doucet, and Eric Pantin, (CEA Saclay, France), Sebastien Charnoz (Paris 7 Denis Diderot University), Emilie Habart (Institut d'Astrophysique Spatiale, Orsay, France), Gaspard Duch?TMne, Fran?ßois M?©nard, and Christophe Pinte (Laboratoire d'Astrophysique de Grenoble, France), and Jan-Willem Pel (Groningen University, The Netherlands)

[1] VISIR - the VLT Imager and Spectrometer for the InfraRed - is a complex multi-mode instrument designed to operate in the 10 and 20 microns atmospheric windows, i.e. at wavelengths up to about 40 times longer than visible light and to provide images as well as spectra at a wide range of resolving power up to ~ 30 000. It can sample images down to the diffraction limit of the 8.2-m Melipal telescope (0.3 arcsec at 10 microns wavelength, i.e. corresponding to a resolution of 500 m on the Moon).
[2] By comparison, the Sun is about 4.6 billion years old. Translated to a human timescale, these young stars would be just 3 days old, compared to the Sun's 40 years.

Source European Southern Observatory
Original text
Science Daily 30th September 2006.

Astronomers Discover Planet Building Is Big Mess

ENLARGE Image: Medium
This artist's concept illustrates how planetary systems arise out of massive collisions between rocky bodies. These catastrophes continue to occur around stars even after they have developed full-sized planets, when they are as old as one hundred million years. For reference, our own Sun, at 4.5 billion years old, is far past this late stage of planet formation. In this image, a young star is shown circled by full-sized planets, and rings of dust beyond. These rings, also called "debris discs" arise when embryonic planets smash into each other. One of these collisions is illustrated in the inset above. Spitzer was able to see the dust generated by these collisions with its powerful infrared vision. Credit: NASA/JPL-Caltech/T. Pyle (SSC-Caltech)

Planets are built over a long period of massive collisions between rocky bodies as big as mountain ranges.

Observations from NASA's Spitzer Space Telescope reveal surprisingly large dust clouds around several stars. These clouds most likely flared up when rocky, embryonic planets smashed together. The Earth's own Moon may have formed from such a catastrophe. Prior to these results, astronomers thought planets were formed under less chaotic circumstances.
"It's a mess out there," said Dr. George Rieke of the University of Arizona, Tucson, first author of the findings and a Spitzer scientist. "We are seeing that planets have a long, rocky road to go down before they become full grown."
Spitzer was able to see the dusty aftermaths of these collisions with its powerful infrared vision. When embryonic planets, the rocky cores of planets like Earth and Mars, crash together, they are believed to either merge into a bigger planet or splinter into pieces. The dust generated by these events is warmed by the host star and glows in the infrared, where Spitzer can see it.

They mirror what we know about the formation of our own planetary system. Recent observations from studies of our Moon's impact craters also reveal a turbulent early solar system. "Our Moon took a lot of violent hits when planets had already begun to take shape," Rieke said.

According to the most popular theory, rocky planets form somewhat like snowmen. They start out around young stars as tiny balls in a disc-shaped field of thick dust. Then, through sticky interactions with other dust grains, they gradually accumulate more mass. Eventually, mountain-sized bodies take shape, which further collide to make planets.
Previously, astronomers envisioned this process proceeding smoothly toward a mature planetary system over a few million to a few tens of millions of years. Dusty planet-forming discs, they predicted, should steadily fade away with age, with occasional flare-ups from collisions between leftover rocky bodies.

Rieke and his colleagues have observed a more varied planet-forming environment. They used new Spitzer data, together with previous data from the European Space Agency's Infrared Space Observatory and the joint NASA, United Kingdom and the Netherlands' Infrared Astronomical Satellite. They looked for dusty discs around 266 nearby stars of similar size, about two to three times the mass of the Sun, and various ages. Seventy-one of those stars were found to harbor discs, presumably containing planets at different stages of development. But, instead of seeing the discs disappear in older stars, the astronomers observed the opposite in some cases.

"We thought young stars, about one million years old, would have larger, brighter discs, and older stars from 10 to 100 million years old would have fainter ones," Rieke said. "But we found some young stars missing discs and some old stars with massive discs."
This variability implies planet-forming discs can become choked with dust throughout the discs' lifetime, up to hundreds of millions of years after the host star was formed. "The only way to produce as much dust as we are seeing in these older stars is through huge collisions," Rieke said.

Before Spitzer, only a few dozen planet-forming discs had been observed around stars older than a few million years. Spitzer's uniquely sensitive infrared vision allows it to sense the dim heat from thousands of discs of various ages. "Spitzer has opened a new door to the study of discs and planetary evolution," said Dr. Michael Werner, project scientist for Spitzer at NASA's Jet Propulsion Laboratory, Pasadena, Calif.
"These exciting new findings give us new insights into the process of planetary formation, a process that led to the birth of planet Earth and to life," said Dr. Anne Kinney, director of the universe division in the Science Mission Directorate at NASA Headquarters, Washington. "Spitzer truly embodies NASA's mission to explore the universe and search for life," she said.
JPL manages the Spitzer Space Telescope for NASA's Science Mission Directorate. Artist's concepts and additional information about the Spitzer Space Telescope is available at
NASA Jet Propulsion
Original text:
Science Daily 19th October 2004.

Spitzer Sees Dusty Aftermath Of Pluto-Sized Collision

ENLARGE Image: Medium
Massive Smash-Up at Vega: This artist concept illustrates how a massive collision of objects, perhaps as large as the planet Pluto, smashed together to create the dust ring around the nearby star Vega. New observations from NASA's Spitzer Space Telescope indicate the collision took place within the last one million years. Astronomers think that embryonic planets smashed together, shattered into pieces, and repeatedly crashed into other fragments to create ever finer debris. (Credit: NASA/JPL-Caltech/T. Pyle (SSC/Caltech))

Astronomers say a dusty disc swirling around the nearby star Vega is bigger than earlier thought. It was probably caused by collisions of objects, perhaps as big as the planet Pluto, up to 2,000 kilometers (about 1,200 miles) in diameter.

NASA's Spitzer Space Telescope has seen the dusty aftermath of this "run-in." Astronomers think embryonic planets smashed together, shattered into pieces and repeatedly crashed into other fragments to create ever-finer debris. Vega's light heats the debris, and Spitzer's infrared telescope detects the radiation.

Vega, located 25 light-years away in the constellation Lyra, is the fifth brightest star in the night sky. It is 60 times brighter than our Sun. Observations of Vega in 1984, with the Infrared Astronomical Satellite, provided the first evidence for dust particles around a typical star. Because of Vega's proximity and because its pole faces Earth, it provides a great opportunity for detailed study of the dust cloud around it.

Like a drop of ink spreading out in a glass of water, the particles in Vega's dust cloud don't stay close to the star long. The dust we are seeing in the Spitzer images is being blown out by intense light from the star. We are witnessing the aftermath of a relatively recent collision, probably within the last million years.
Scientists say this disc event is short-lived. The majority of the detected material is only a few microns in size, 100 times smaller than a grain of Earth sand. These tiny dust grains leave the system and dissipate into interstellar space on a time scale less than 1,000 years. But there are so many tiny grains. They add up to a total mass equal to one third of the weight of our moon.

The mass of these short-lived grains implies a high dust-production rate. The Vega disc would have to have an improbably massive reservoir of planet-building material and collisions to maintain this amount of dust production throughout the star's life (350 million years, 13 times younger than our Sun). "We think a transient disc phenomenon is more likely," Su said.

Astronomers were struck by other characteristics of Vega's debris disc, including its physical size. It has a radius of at least 815 astronomical units, roughly 20 times larger than our solar system. One astronomical unit is the distance from Earth to the Sun, which is 150million kilometers (93- million miles). A study of the disc's surface brightness indicates the presence of an inner hole at a radius of 86 astronomical units (twice the distance between Pluto and the Sun). Large embryonic planets at the edge of this inner hole may have collided to make the rest of the debris around Vega.

"Spitzer has obtained the first high spatial-resolution infrared images of Vega's disc," said Dr. Michael Werner, co-author and project scientist for Spitzer at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Its sensitive infrared detectors have allowed us to see that Vega is surrounded by an enormous disc of debris."

JPL manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. JPL is a division of Caltech. The multi-band imaging photometer for Spitzer, which made the new disc observations, was built by Ball Aerospace Corporation, Boulder, Colo.; the University of Arizona; and Boeing North American, Canoga Park, Calif. Additional information about the Spitzer Space Telescope is available at http://www.spitzer.caltech.edu.
University of Arizona
Original text:
Science Daily 18th January 2005.

Famous Quotes History is a gallery of pictures
in which there are few originals and many copies.
Alexis de Tocqueville

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