Wednesday, February 28, 2007

Intergalactic Art

Bubble Worlds - from
Stacey Whaley
@ Intergalacticart

Please note this is a Mind Expanding Draft.
Exploring Phase Transitions of Matter, Energy, Light ...
And will also take a closer look at cell division in biology
Planets of the solar system, stars in galaxies, in the cosmos we see

The concept of entropy in thermodynamics is central to the second law of thermodynamics, which deals with physical processes and whether they occur spontaneously. Spontaneous changes occur with an increase in entropy.

Spontaneous changes tend to smooth out differences in temperature, pressure, density, and chemical potential that may exist in a system, and entropy is thus a measure of how far this smoothing-out process has progressed. In contrast, the first law of thermodynamics deals with the concept of energy, which is conserved.

Hydrostatic equilibrium is the reason stars don't implode, or explode. In astrophysics, in any given layer of a star, there is a balance between the thermal pressure (outward) and the weight of the material above pressing downward (inward). This balance is called hydrostatic equilibrium. A star is like a balloon.

In a balloon, the gas inside the balloon pushes outward and the Earth's atmospheric pressure plus the elastic material supply just enough inward compression to balance the gas pressure. In the case of a star, the star's internal gravity supplies the inward compression. The isotropic gravitational field compresses the star into the most compact shape possible: a sphere.

"Is the 'visible world' or cosmos an isolated system, and not itself just a bubble in a larger sea, incidentally a bubble in a sea so vast, we would have no idea of knowing where or how to start assuming when equilibrium might or would be reached"

"Is cell life the ultimate manifestation of Nature in Nature" Quasar9
Bubble Worlds - from Stacey Whaley @ Intergalacticart

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Monday, February 26, 2007

Pulsar's creation.

Volume rendering of 3-D simulation of a pulsar's formation. Credit: Image courtesy of North Carolina State University

Pulsars are rapidly rotating neutron stars formed in supernova explosions, which occur when a massive star reaches the end of its life and explodes. The remaining matter is compressed into a dense, rapidly spinning mass – a neutron star, or pulsar – so-called because scientists first discovered them due to their regularly timed radio emissions.

Pulsars spin very rapidly – 20 or more times per second. Scientists have assumed that the spin was caused by the conservation of angular momentum from a star that was spinning before it exploded.

“Think about figure skaters,” Blondin says. “They start a spin with their arms and legs farther out from the body, and increase their rotation speed when they pull their limbs in more tightly. That’s what the conservation of angular momentum is – the idea that if you take a large object with a slight rotation and compress it down, the rotation speed will increase.”

However, scientists had no idea if the stars that were producing the pulsars were even spinning to begin with. Blondin and his colleague decided to create a computer model of a supernova explosion using the new Cray X1E supercomputer at the National Center for Computational Sciences, the only computer with enough processing power to accomplish the task. The resultant model demonstrated that a pulsar’s spin doesn’t have anything to do with whether or not the star that created it was spinning; instead, the spin is created by the explosion itself.

“We modeled the shockwave, which starts deep inside the core of the star and then moves outward,” Blondin says. “We discovered that as the shockwave gains both the momentum and the energy needed to blow outward and create the explosion, it starts spiraling all on its own, which starts the neutron star at the center of the star spinning in the opposite direction. None of the previous two-dimensional modeling of supernova explosions had picked up on this phenomena.”

Dr. John Blondin, professor of physics in NC State’s College of Physical and Mathematical Sciences, along with colleague Anthony Mezzacappa at the Oak Ridge National Laboratory.
Their findings are published in the Jan. 4 edition of the journal Nature.

Latest Spin on Neutron Stars from Louise Riofrio
Scientist Discovers New Explanation For Pulsar's Spin from Science Daily

Sunlight heats ice on surface of comet McNaught

The unique images reveal three clear jets of gas, which are seen to spiral away from the nucleus as it rotates, like a Catherine Wheel firework.

"These jets are produced when sunlight heats ices on the surface of the comet, causing them to evaporate into space and create 'geyser' like jets of gas and small dust particles, which stretch over 13,000 km into space - greater than the diameter of the Earth - despite the fact that the nucleus of the comet is probably less than 25 km in diameter,"

By comparing images like this taken at different times, astronomers should be able to calculate how fast the nucleus rotates from the changing pattern of jets.

Other images also reveal that while the gas forms spiral jets, the large dust particles released from the comet follow a different pattern, as they are thrown off the comet's surface on the brightly lit side towards the Sun, producing a bright fan, which is then blown back by the pressure of sunlight itself.

Unique Observations Of Comet McNaught Reveal Sprinkling Nucleus
Comet McNaught. Image courtesy of European Southern Observatory

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Saturday, February 24, 2007

Rosetta over Mars

Rosetta Swing-by 250 km over Martian surface
The Rosetta swing-by of Mars is the second of four gravity assist manoeuvres that are required to place Rosetta on course for its final destination.

Timeline: Mars swingby at 36 000 km per hour
The closest approach of the swing-by will take place at 01:54 UT, 25 February 2007, when the spacecraft will pass 250 km above the surface of Mars.

Rosetta's NAVCAM captured the black & white image of Mars at 19:32 CET from a distance of 237 477 km.

In the upper left it is possible to identify the Elysium Mons region centred at approximately 147° East. Mars' equator runs horizontally approximately across the middle of the image.

Just northeast of the 'double finger' feature, visible in the lower half of the disk, is Aeolis Mensae mountain, located at 140° East.

The small double feature visible in the upper-right quadrant is the Cerberus Fossae ridge.

Spectacular view approaching Mars Animations from ESA
Beautiful new images of Mars - OSIRIS UPDATE 25/02/07
Stunning view of Rosetta skimming past Mars - 25/02/07
Rosetta successfully swings-by Mars – next target: Earth
A gravitational slingshot is the use of the gravity of a planet to alter the path and speed of an interplanetary spacecraft. It is a commonly used manoeuvre for visiting the outer planets, which would otherwise be prohibitively expensive, if not impossible, to reach with current technologies. It is also known as a "gravity assist".

A slingshot manoeuvre around a planet changes a spacecraft's velocity relative to the Sun, even though it preserves the spacecraft's speed relative to the planet.

Consider a spacecraft on a trajectory that will take it close to a planet.

As the spacecraft approaches the planet, the planet's gravity will pull on the spacecraft, speeding it up. After passing the planet, the gravity will continue pulling on the spacecraft, slowing it down. The net effect on the speed is zero, although the direction may have changed in the process. (Image Cassini trajectory)

New Engine Helps Satellites Blast Off With Less Fuel
The Georgia Tech engine operates with an efficient ion propulsion system. Xenon (a noble gas) atoms are injected into the discharge chamber. The atoms are ionized, (electrons are stripped from their outer shell), which forms xenon ions.

The light electrons are constrained by the magnetic field while the heavy ions are accelerated out into space by an electric field, propelling the satellite to high speeds.

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Mystery over Australia

Mystery Over Australia. Credit & Copyright: Ray Palmer

Click on Image to enlarge this stunning view through dark skies over western Australia and the highlights of the southern Milky Way -- including the famous Southern Cross, the dark Coal Sack Nebula, and bright reddish emission regions surrounding massive star Eta Carinae.

The thirty minute long colour film exposure also captured a bright but mysterious object that moved slowly across the sky for over an hour. Widely seen, the object began as a small point and expanded as it tracked toward the North (left), resulting in a comet-like appearance in this picture. What was it?

Reports are now identifying the mystery glow with a plume from the explosion of a malfunctioned Russian rocket stage partially filled with fuel. The rocket stage was marooned in Earth orbit after a failed communication satellite launch almost a year ago on February 28, 2006. A substantial amount of debris from the breakup can be tracked.

Discover the Cosmos with Astronomy Picture of the Day
20MB Video with spectacular explosion from Gordon Garradd
Currently there are approximately 2465 artificial satellites orbiting the Earth and 6216 pieces of space debris as tracked by the Goddard Space Flight Center. Over 16,291 previously launched objects have decayed into the Earth's atmosphere.

Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time. On 24 Feb 2007 there were 846 known PHAs

Wishing You All A Magical weekend!

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Friday, February 23, 2007

String of Cosmic Pearls

A String of 'Cosmic Pearls' Surrounds an Exploding Star

On Feb 23 1987 astronomers witnessed one of the brightest stellar explosions in more than 400 years. The titanic supernova, called SN 1987A, blazed with the power of 100 million suns for several months following its discovery. Observations of SN 1987A, made since by NASA’s Hubble Space Telescope and many other major ground- and space-based telescopes, have significantly changed astronomers' views of how massive stars end their lives. Astronomers credit Hubble's sharp vision with yielding important clues about the massive star's demise.

This Hubble telescope image shows the supernova’s triple-ring system, including the bright spots along the inner ring of gas surrounding the exploded star. A shock wave of material unleashed by the stellar blast is slamming into regions along the inner ring, heating them up, and causing them to glow. The ring, about a light-year across, was probably shed by the star about 20,000 years before it exploded

Full story ... from Hubblesite releases

XMM-Newton view of supernova SN 1987A

XMM-Newton’s anniversary view of supernova SN 1987A
Twenty years after the first detection of SN 1987A, the nearest supernova ever detected since the invention of the telescope, XMM-Newton provided a fresh-new view of this object. The source keeps brightening - XMM-Newton confirms.

SN 1987A provides the unique opportunity for detailed studies of the earliest stages of a supernova remnant. Observations across the whole electromagnetic spectrum revealed a detailed picture of the circumstellar medium produced by the stellar wind from the massive pregenitor star during its 'supergiant' phases.

The X-rays we see mainly originate from the interaction of the supernova shock with this circumstellar medium. Their detailed analysis will gain further insights into the physics of the explosion and may reveal eventually the presence of a central compact object like a neutron star.

More on Supernova 1987a - by Stefan @ Backreaction
The Theory of Evolution of Supernovae from Dialogues of Eide
Taurus-Auriga: XMM-Newton reveals a magnetic surprise

As part of a large programme to survey Taurus-Auriga at X-ray wavelengths, XMM-Newton systematically targeted AB Aurigae and the other young stars in this region, using its European Photon Imaging Camera (EPIC). AB Aurigae stood out brightly in the image, indicating that it was releasing X-rays.

At 2.7 times the mass of the Sun, AB Aurigae is one of the most massive stars in the Taurus-Auriga star-forming cloud. Although amongst nearly 400 smaller stars, its ultraviolet radiation plays a key role in shaping the cloud. Its massive status puts it in a class known as Herbig stars, named after their discoverer George Herbig.

X-rays are expected to come from young stars with strong magnetic fields but computer calculations have repeatedly suggested that Herbig stars do not have the correct internal conditions to generate an appreciable magnetic field. Yet for twenty years, astronomers have been detecting X-ray emission from them.

Full story ... XMM-Newton reveals a magnetic surprise
Map of TAURUS, AURIGA (Chariot), GEMINI, ORION & The Pleiades by uiuc
Cosmic Lighthouses: Astrophysicists from the Max Planck Institute
Explain Differences In Brightness Of Supernova Explosions

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Wednesday, February 21, 2007

Integral View of Sky

Credits: IBIS survey team

Integral expands our view of the gamma-ray sky
The upper image shows the sky distribution of four of the main soft gamma-ray source populations observed in the third Integral/IBIS survey catalogue. This newly-released catalogue contains 421 sources. Of the known systems, the low-mass X-ray binaries (LMXB) are old systems mainly populating the galactic bulge, the high-mass X-ray binaries (HMXB) are younger systems seen along the galactic plane, and the active galactic nuclei (AGN) are extragalactic sources seen over the whole sky. Around one out of four of the sources seen by Integral are unidentified, and their distribution is also shown.

The lower picture is a false colour image of the central region of our galaxy. This is a composite image based on all-sky IBIS/ISGRI maps in three energy windows (between 17 and 100 keV) and represents the true 'X-ray colours' of the sources. Red sources are dominated by emission below 30 keV, while blue sources have harder spectra, emitting strongly above 40 keV.

One of the most remarkable "relic" gamma-ray clouds of the new catalog, the source HESS J1825-137 which is 100 light-years across. The zoomed box shows the much smaller X-ray nebula (data from the XMM-Newton satellite), surrounding the middle-aged (21000 years old) pulsar PSR B1823-13. (Credit: Astroparticule et Cosmologie (APC), CNRS)

High-Energy 'Relic' Wind Reveals Past Behavior Of Dead Stars
Winds from pulsars have been known for many years. The most famous example is that from the pulsar in the center of the Crab Nebula, a bright cloud of expanding gas from a star that exploded in the year 1054. In that case, the wind generates X-rays (which have less energy than gamma rays) through synchrotron radiation and gamma rays through the inverse Compton scattering. These X-rays and gamma rays are seen coming from gas a few light years across at most.

The objects detected by the H.E.S.S. team are far more extended. The glow of gamma rays seen from the pulsar PSR B1823-13, for example, is approximately 100 light years across. A light year is the distance a particle of light, traveling 186,000 miles per second travels in one year.

The larger size of this gamma-ray emitting region means the electrons producing the gamma rays have traveled further and so come from a period earlier in the pulsar’s history. This in turn means that studying the gamma rays from pulsar winds can give astronomers insight into the history of the pulsar itself and how its magnetic field has changed over the past tens of thousands of years.

Powerful Solar Winds colliding head-on from Universe Today
NASA Scientists Find High Energy Systems Hidden in 'Gas Cocoon'
First X-Ray detection of a Colliding Wind Binary from Science Daily

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Monday, February 19, 2007

Coronal Mass Ejection


A Coronal Mass Ejection (CME) blasting off the Sun’s surface in the direction of Earth. In this image, the left portion is composed of an EIT 304 image superimposed on a LASCO C2 coronagraph. Two to four days later, the CME cloud is shown striking and beginning to be mostly deflected around the Earth’s magnetosphere. The blue paths emanating from the Earth’s poles represent some of its magnetic field lines. The magnetic cloud of plasma can extend to 30 million miles wide by the time it reaches earth. These storms, which occur frequently, can disrupt communications and navigational equipment, damage satellites, and even cause blackouts.

The Sun connects with all the planets via the solar wind, a flow of electrically charged particles that constantly 'blows' off the Sun and creates 'space weather'. Space weather interactions can affect and erode the atmospheres of Earth and other planets, and, when channelled through a planetary magnetic field, create beautiful aurorae. Until now, physicists have been principally concerned with the way the solar wind interacts with Earth, the so-called Sun-Earth connection. Now it is time to think bigger.

Credits: ESA/David Hardy

Ulysses has made fundamental contributions to our understanding of the Sun, the heliosphere, and our local interstellar neighbourhood. Charged particles are in fact ‘tied’ by electromagnetic forces and follow the magnetic field lines in space. In the case of the Sun, which is a rotating object, so the field lines are actually twisted into spirals like water from a garden sprinkler.

In mid-December 2006, although very close to the minimum of its 11-year sunspot cycle, the Sun showed that it is still capable of producing a series of remarkably energetic outbursts.

The solar storms, which were confined to the equatorial regions, produced quite intense bursts of particle radiation that were clearly observed by near-Earth satellites. Surprisingly, similar increases in radiation were detected by the instruments on board Ulysses, even though it was three times as far away and almost over the south solar pole. Particle events of this kind were seen during the second polar passes in 2000 and 2001, at solar maximum.

Scientists are busy trying to understand how the charged particles made it all the way to the poles. "Charged particles have to follow magnetic field lines, and the magnetic field pattern of the Sun near solar minimum ought to make it much more difficult for the particles to move in latitude.

Surprises from the Sun’s South Pole from ESA Int 19/02/07
International Heliophysical Year begins from ESA Int 19/02/07
A Year of observing the Sun-Earth relationship Starts PPARC.
The New Solar System from Ryan Wyatt @ Visualising Science.

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Dark Galaxies

Ghostly galaxies speckle the universe. Unlike normal galaxies, these extreme systems contain very few stars and are almost devoid of gas. Most of the luminous matter, so common in most galaxies, has been stripped away, leaving behind a "spectral" shadow.
[+/-] Click here to expand

These intriguing galaxies-known as dwarf spheroidals are so faint that, although researchers believe they exist throughout the universe, only those relatively close to Earth have ever been observed. And until recently, no scientific model proposed to unravel their origin could simultaneously explain their exceptional content and their penchant for existing only in close proximity to much larger galaxies.

Using supercomputers to create novel simulations of galaxy formation, Kazantzidis and his collaborators found that a "dark matter" dominated galaxy begins life as a normal system. But when it approaches a much more massive galaxy, it simultaneously encounters three environmental effects - "ram pressure," "tidal shocking" and the cosmic ultraviolet background-that transform it into a mere shadow of its former self.

About 10 billion years ago, when the gas-rich progenitors of "dark matter" dominated galaxies originally fell into the Milky Way, the universe was hot with a radiation called the cosmic ultraviolet background. As a small satellite galaxy traveled along its elliptical path around a more massive galaxy, called the host, this radiation made the gas within the smaller galaxy hotter. This state allowed ram pressure - a sort of "wind resistance" a galaxy feels as it speeds along its path - to strip away the gas within the satellite galaxy.

Simultaneously, as the satellite galaxy moved closer to the massive system, it encountered the overwhelming gravitational force of the much larger mass. This force wrenched luminous stars from the small galaxy. Over billions of years of evolution, the satellite passed by the massive galaxy several times as it traversed its orbital path. Each time its stars shook and the satellite lost some of them as a result of a mechanism called "tidal shocking". These effects conspired to eventually strip away nearly all the luminous matter gas and stars, and left behind only a shadow of the original galaxy.

The remaining matter, on the other hand, was nongaseous and therefore unaffected by the ram pressure force or the cosmic ultraviolet background, the scientists posit. It did experience tidal shocking, but this force alone was not strong enough to pull away a substantial amount of the remaining matter or "dark matter".

Scientists elucidate the origin of the darkest galaxies in the universe
from Stanford University news (Image courtesy of Stanford University)

Stem cells determine the daughter cells' fate

Intestinal stem cells (ISCs) in the gut of the fruit fly, Drosophila melanogaster, directly determine the fate of their daughter cells. The signaling protein called Delta, seen here in red, determines what type of cell the ISCs will produce.

Large amounts of Delta signal the daughter cells to become gut-lining enterocytes (left panel), while small amounts of Delta signal them to become hormone-generating enteroendocrine cells (see image). (Credit: Images used with permission of the American Association for the Advancement of Science, Science, February 16, 2007)
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From roundworm to human, most cells in an animal’s body ultimately come from stem cells. When one of these versatile, unspecialized cells divides, the resulting “daughter” cell receives instructions to differentiate into a specific cell type. In some cases this signal comes from other cells. But now, for the first time, researchers at the Carnegie Institution’s Department of Embryology have found a type of stem cell that directly determines the fate of its daughters.

Stem cells can participate actively in determining what type of cell their daughters will become right at the moment of stem cell division, suggesting that tissue stem cells might not just be a source of new cells, but could actually be the ‘brains’ of the tissue - the cells that figure out what type of new cell is needed at any given moment.

Because they truly can become any cell in the body, “embryonic” stem cells tend to receive a lot of attention. Yet “adult” stem cells remain in fully-developed organisms, where they replace specific cell types lost to age or disease.

Read more Stem Cells Determine Their Daughters' Fate

arxiv find dark matter from Sean @ Cosmic Variance
In Search of Dark Matter Galaxies from Centauri Dreams

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Saturday, February 17, 2007

Universal Feast

Photo thanks to Jimmy James @ Under The Ledge click image to enlarge

Logic would dictate that just as there is space time, there is Space outside TIME.

In spacetime we can take a snapshot and freeze time, we can even rewind a film on video or dvd, but we do this travelling forward thru time. Even when we look at the distant stars and galaxies in the universe, we are looking at the light that reaches us on Earth, from a time long past.
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Time (and even Space) as we shall see is relative to the observer, and as humans we are travelling thru time (and ageing over time).

It is movement that creates the impermanence of time, but there must be a Space outside Time where motion (or movement) is possible without decay, ageing, disease, suffering or death - among the multiverses that Leonard Susskind & Alex Vilenkin would like us to be aware of (see or imagine) - they seem to have ommited the one Above All where Time itself does not exist.

Just for a moment imagine yourself looking at a film of yourself on a 2D or 3D screen, now take a further step back and look at yourself in 3D+T (from outside Time).


Stephen Hawking has worked on the basic laws which govern the universe. With Roger Penrose he showed that Einstein's General Theory of Relativity implied space and time would have a beginning in the Big Bang and an end in black holes.

These results indicated it was necessary to unify General Relativity with Quantum Theory, the other great Scientific development of the first half of the 20th Century. One consequence of such a unification that he discovered was that black holes should not be completely black, but should emit radiation and eventually evaporate and disappear.

Another conjecture is that the universe has no edge or boundary in imaginary time. This would imply that the way the universe began can be completely determined by the laws of science.

Stephen Hawking

We live in the aftermath of a great explosion. This awesome event, called somewhat frivolously the big bang, took place about 14 billion years ago. We can actually see some of the cosmic history unfolding before us since that moment—light from remote galaxies takes billions of years to reach our telescopes on earth, so we can see galaxies as they were in their youth.

But there is a limit to how far we can see into space. Our horizon is set by the maximum distance light could have traveled since the big bang. Sources more distant than the horizon cannot be observed, simply because their light has not yet had time to reach Earth.

And if there are parts of the universe we cannot detect, who can resist wondering what they look like? Until recently physicists thought that the answer to this question is rather boring: it’s just more of the same – more galaxies, more stars. But now, recent developments in cosmology have led to a drastic revision of that view.

According to the new picture, distant parts of the universe are in the state of explosive, accelerated expansion, called “inflation”. The expansion is so fast that in a tiny fraction of a second a region the size of an atom is blown to dimensions much greater than the entire currently observable universe. The expansion is caused by a peculiar form of matter, called “false vacuum”, which produces a strong repulsive force.

The word “false” refers to the fact that, unlike the normal “true” vacuum, this type of vacuum is unstable and typically decays after a brief period of time, releasing a large amount of energy. The energy ignites a hot fireball of particles and radiation. This is what happened in our cosmic neighborhood 14 billion years ago – the event we refer to as the big bang.

With inflation, the two competing processes are the decay of the false vacuum and its “reproduction” by rapid expansion of the inflating regions. My calculations, and those of Andrei Linde, show that false-vacuum regions multiply much faster than they decay, and thus their volume grows without bound.

At this very moment, some distant parts of the universe are undergoing exponential inflationary expansion. Other regions like ours, where inflation has ended, are also constantly being produced. They form “island universes” in the inflating sea of false vacuum. Because of inflation, the space between the islands rapidly expands, making room for more island universes to form.

Inflation is thus a runaway process that has stopped in our neighborhood, but still continues in other parts of the universe, causing them to expand at a furious rate and constantly spawning new island universes like our own. This never ending process is referred to as “eternal inflation”.

The role of the big bang in this scenario is played by the decay of the false vacuum. It is no longer a one-time event in our past: multiple bangs went off before it in remote parts of the universe, and countless others will erupt elsewhere in the future.

Analysis shows that the boundaries of island universes expand faster than the speed of light. (Einstein’s ban on super-luminal speeds applies to material bodies, but not to geometric entities such as the boundary of an island.) It follows that, regrettably, we will never be able to travel to another island, or even send a message there. Other island universes are unobservable, even in principle.

In the global view of eternal inflation, the boundaries of island universes are the regions where big bangs are happening right now. Newly formed islands are microscopically small, but they grow without limit as they get older. Central parts of large island universes are very old: big bangs once took place there long time ago. Now they are dark and barren: all stars have long since died there. But regions at the periphery of the islands are new and must be teeming with shining stars.

The inhabitants of island universes, like us, see a different picture. They do not perceive their universe as a finite island. For them it appears as a self-contained, infinite universe. That dramatic difference in perspective is a consequence of the differences imposed by the ways of keeping time appropriate to the global and internal views of the island universe. (According to Einstein's theory of relativity, time is not fixed, but instead is observer dependent.)

Perhaps the easiest way to see this is to count galaxies. In the global view, new galaxies are continually formed near the expanding boundaries, so as time passes, we have an infinite number of galaxies in the limit. In the internal view, all this infinity of galaxies exists simultaneously (say, at time 14 billion years). The implications are extraordinary.

Since each island universe is infinite from the viewpoint of its inhabitants, it can be divided into an infinite number of regions having the same size as our own observable region. My collaborator Jaume Garriga and I call them O-regions for short. As it happens, the most distant objects visible from Earth are about 40 billion light-years away, so the diameter of our own O-region is twice that number.

Quantum fluctuations in the course of eternal inflation ensure that all possible values of the constants are realized somewhere in the universe. As a result, remote regions of the universe may drastically differ in their properties from our observable region. The values of the constants in our vicinity are determined partly by chance and partly by how suitable they are for the evolution of life. The latter effect is called anthropic selection.

Another recent application of the principle of mediocrity, unrelated to string theory, is to the amount of dark matter in the universe. As its name suggests, dark matter cannot be seen directly, but its presence is manifested by the gravitational pull it exerts on visible objects. The composition of dark matter is unknown. One of the best motivated hypotheses is that it is made up of very light particles called axions. The density of axionic dark matter is set by quantum fluctuations during inflation and varies from one place in the universe to another.

Alex Vilenkin

However, it is clear that just as photons can be in many possible places but are only actually in one, we as humans though we can potentially be in many places are only actually ever in one, and that one place will be wherever we happen to be in 1) our physical body, and 2) our mind or mental state.

All our other states in Vilenkin's multiverses are effectively or conceptually in a different time frame, or outside Time - but they are unlikely to be at the same time. After all we can talk to many people in an auditorium or through tv, but we can only ever hold a one to one with one person at a time, and a dialogue or conversation with a few at most - even during video conferencing.

The multiverse is like a flower from Dialogues of Eide
Quantum Phase Transitions from Science Daily releases
Universe offers 'eternal feast' by

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Friday, February 16, 2007

Blue electron light

The blue streak in this photograph shows the dramatic gain in energy made by some of the electrons in a bunch after passing through plasma (ionized gas). The white spot shows the electrons in the bunch that generated the plasma to propel the other electrons to double their energy, to 85 billion electron volts (GeV). The electrons can be photographed because they emit blue light as they pass through air.
Click on image for larger version

Electrons already travel at near light's speed in an accelerator, but physicists from the Stanford Linear Accelerator (SLAC) actually doubled the energy of the electrons, not their speed.

This achievement demonstrates a technology that may drive the future of accelerator design. To reach the high energies required to answer the new set of mysteries confronting particle physics—such as dark energy and the origin of mass—the newest accelerators are vastly larger, and consequently more expensive, than their predecessors. Very high-energy particle beams will be needed to detect the very heavy and very short-lived particles that have eluded scientists so far.

While still in early development stages, the research shows that acceleration using plasma, or ionized gas, can dramatically boost the energy of particles in a short distance.

The electrons first traveled two miles through the linear accelerator at SLAC, gaining 42 billion electron volts (or GeV) of energy. Then they passed through a 33-inch long (84-centimeter) plasma chamber and picked up another 42 GeV of energy. Like an afterburner on a jet engine, the plasma provides extra thrust. The plasma chamber is filled with lithium gas. As the electron bunch passes through the lithium, the front of the bunch creates plasma. This plasma leaves a wake that flows to the back of the bunch and shoves it forward, giving electrons in the back more energy.

The experiment created one of the largest acceleration gradients ever achieved. The gradient is a measure of how quickly particles amass energy. In this case, the electrons hurtling through the plasma chamber gained 3,000 times more energy per meter than usual in the accelerator.

A current experimental limitation is that most of the electrons in a bunch lose their energy to the plasma. Energy out of one part of the beam is put into another part.

During the last two years, the team has improved the plasma acceleration gradient by a factor of 200. One of the next steps is to attempt a two-bunch system, where the first bunch provides all the energy to the trailing bunch. In a full-scale plasma accelerator, physicists would use those second bunches to create high-energy particle collisions in their detectors.

New Accelerator Technique Doubles Particle Energy in Just One Meter
SLAC press release 14/02/07

Supergiant fast X-Ray transients

Credits: ESA This artist's impression shows a high-mass binary system, composed of a supergiant luminous star (in blue) and a compact stellar object, such as a neutron star.

As discovered by ESA's Integral observatory, many of these supergiant systems produce strong and exceptionally fast-rising X-ray outbursts lasting a few hours only, hence their name 'supergiant fast X-ray transients'.

The outbursts may depend on the way stellar material is exchanged between the supergiant star and the compact object.

The light curve at the bottom-right was retrieved by Integral from the supergiant fast X-ray transient source IGR J17544-2619 on 17 September 2003.

The curve shows a very fast X-ray outburst from the compact object, lasting about two hours only, with very fast rise and slow decay. The counterpart of this source is a luminous supergiant, unambiguously identified by ESA's XMM-Newton and NASA's Chandra X-ray observatories.

Credits: JM Blondin, North Carolina State University

This simulated sequence shows the interaction between the stellar material carried by the wind of a supergiant star and its 'receiving' companion - a compact stellar object such as a neutron star. In the vicinity of the compact object it is possible to see the development of a turbulent shocked flow.

Integral reveals new class of ‘supergiant’ X-ray binary stars
LHC - The worlds largest microscope
by Sabine Hossenfelder @ Backreaction

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Wednesday, February 14, 2007

At Heart a White Star


Hubble's Wide Field Planetary Camera 2 captured this image of planetary nebula NGC 2440 on 6th Feb 2007. The image shows a star like our Sun ending its life by casting off its outer layers of gas, which formed a cocoon around the star's remaining core. Ultraviolet light from the dying star then makes the material glow.

The burned-out star, called a white dwarf, appears as a white dot in the center. Our Milky Way Galaxy is littered with these stellar relics, called planetary nebulae.

The colours correspond to material expelled by the star. Blue corresponds to helium; blue-green to oxygen; and red to nitrogen and hydrogen.

The Colorful Demise of a Sun-like Star from hubblesite 13/02/07

Spitzer’s infrared view of the Helix nebula. Credit: NASAs Spitzer Space Telescope

Spitzer's spectacular new view of the Helix nebula shows colours as seen in infrared. The dusty white star appears as a dot in the middle of the nebula, like a red pupil in a shimmering cloud of gas with an eerie resemblance to a giant eye.

Comets Clash at Heart of Helix Nebula Spitzer Media release 12/02/07
More on Debris Disk Around a Dead Star from Centauri Dreams.
The bright White Light from our closest star - The Sun

The Sun as it appears through a camera lens from the surface of Earth

The Sun has a surface temperature of approximately 5,500 K, giving it a white colour, which, because of atmospheric scattering, appears yellow. This is a subtractive effect, as the preferential scattering of blue photons (that 'colour' the sky) removes enough blue light to leave a residual reddishness that is perceived as yellow.

The high-energy photons (gamma and X-rays) released in fusion reactions take a long time to reach the Sun's surface, slowed down by the indirect path taken, as well as by constant absorption and reemission at lower energies in the solar mantle. Estimates of the "photon travel time" range from as much as 50 million years to as little as 17,000 years.

After a final trip through the convective outer layer to the transparent "surface" of the photosphere, the photons escape as visible light.

Each gamma ray in the Sun's core is converted into several million visible light photons before escaping into space. Neutrinos are also released by the fusion reactions in the core, but unlike photons they very rarely interact with matter, so almost all are able to escape the Sun immediately.

For many years measurements of the number of neutrinos produced in the Sun were much lower than theories predicted, a problem which was recently resolved through a better understanding of the effects of neutrino oscillation.
LHC - The worlds largest microscope
by Sabine Hossenfelder @ Backreaction

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Monday, February 12, 2007

The travels of Ulysses


Less than one hundred years ago, the south pole of Earth was a land of utter mystery. It was terra incognita until intrepid Explorers Roald Amundsen and Robert F. Scott, fighting wind, disorientation and a fantastic almost-martian cold reached the Pole in 1911 and 1912

The situation is much the same today on the sun. "The sun's south pole is uncharted territory," says solar physicist Arik Posner of NASA headquarters. "We can barely see it from Earth, and most of our sun-studying spacecraft are stationed over the sun's equator with a poor view of higher latitudes."

There is, however, one spacecraft that can travel over the sun's poles. "On February 7th, Ulysses reached a maximum heliographic latitude of 80 degrees South - almost directly above the South Pole," says Posner who is the Ulysses Program Scientist for NASA.

Ulysses has flown over the sun's poles only twice before--in 1994-95 and 2000-01. The flybys were brief, but enough to prove that the poles are strange and interesting places.

Consider the following:

1. The sun's north magnetic north pole sticks out the south end of the sun. Magnetically, the sun is upside down!

"Most people don't know it, but we have the same situation here on Earth," notes Posner. "Our magnetic north pole sticks out of the geographic south pole."

"Both the sun's and Earth's magnetic poles are constantly on the move, and they occasionally do a complete flip, with N and S changing places."

This flipping happens every 11 years on the sun in synch with the sunspot cycle. It happens every 300,000 years or so on Earth in synch with--what? No one knows. "Studying the polar magnetic field of the sun might give us some clues about the magnetic field of our own planet."

2. There are coronal holes over the sun's pole. These are places where the sun's magnetic field opens up and allows solar wind to escape. "Flying over the sun's poles, you get slapped in the face by a hot, million mph stream of protons and electrons," Ulysses is experiencing and studying this polar wind right now.

3. Something keeps cosmic rays out of the sun's polar regions. The current flyby gives us a chance to investigate this phenomenon.

4. Another mystery: There is evidence from earlier flybys that the north pole and the south pole of the sun have different temperatures. "We're not sure why this should be," says Posner, "and we're anxious to learn if it is still the case." Today's south polar flyby will be followed by a north polar flyby in early 2008, allowing a direct north vs. south comparison.

Today the spacecraft Ulysses is gliding 300 million km (2 AU) above the sun's 'Antarctic.'

That's a safe distance and a good place to sample the sun's polar winds and magnetic fields.
Ulysses - Exploring Space over the Sun's Poles from ESA
Deep Space Voyage to High Latitudes over the Solar Poles. from NASA
On matters closer to Earth. I shall soon (next month) be starting a closer scrutiny of medical advances, standards in health care and nhs practices in Cambridge on the other site Torchwood

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Saturday, February 10, 2007

Galactic Centre

Stars of the Galactic Center - Credit: Susan Stolovy (SSC/Caltech) et al., JPL-Caltech, NASA

The center of our Milky Way is hidden from the prying eyes of optical telescopes by clouds of obscuring dust and gas.

But in this stunning vista, the Spitzer Space Telescope's infrared cameras, penetrate much of the dust revealing the stars of the crowded galactic center region. A mosaic of many smaller snapshots, the detailed, false-color image shows older, cool stars in bluish hues. Reddish glowing dust clouds are associated with young, hot stars in stellar nurseries. The galactic center lies some 26,000 light-years away, toward the constellation Sagittarius.

At that distance, this picture spans about 900 light-years.

Discover the Cosmos with Astronomy Picture of The Day
A Cold, Bright Universe from Centauri Dreams
Magnetic Explosions In The Distant Universe from Science Daily
Hubble illuminates large Cluster of Diverse Galaxies Hubblesite.

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Friday, February 09, 2007

Polar Lights

In an old television tube (not the recent LCD or plasma TV screens), accelerated electrons hit a phosphorescent screen and cause the phosphor to glow. The acceleration region generating the aurora works similarly.

Electrons in the atmosphere get accelerated in an 'acceleration region' between about 5000 and 8000 kilometres altitude, and rush down to the Earth's ionosphere – a region of the upper atmosphere. They finally crash into ionospheric atoms and molecules, transferring to them some of the energy and cause them to glow, creating aurorae.

Giant electrical circuits power the magical open-air light show of the auroras, forming arcs in high-latitude regions like Scandinavia. New results obtained thanks to ESA's Cluster satellites provide a new insight into the source of the difference between the two types of electrical circuits currently known to be associated to the auroral arcs.

Auroras form in high latitude regions of Earth, and appear in many different shapes.

The aurora in the early evening sky forms a green arc that stretches across the sky in an east-west direction. The longitudinal extent (length) of an auroral arc can be as large as several thousands kilometres, but its width can be as small as 100 metres.
The deep mechanisms that rule the creation of such beutiful natural light displays (also called polar lights), have been the subject of studies that have been keeping solar and plasma scientists busy for years, with more to come. While early rockets and ground-observations have already provided a few important clues for the understanding of these phenomena, the real break-throughs in our knowledge have started with dedicated auroral satellites, such as S3-3, Dynamics Explorer, Viking, Freja and FAST, and have now come to full fruition with ESA's multi-point mission Cluster.

Photo Credits: Jan Curtis, Fairbanks, Alaska

Artistic view of electrons, responsible for aurora, spiralling down magnetic field lines. The U-shaped potential structure illustrates the region where electrons get accelerated on their way down to the upper atmosphere. Here they are stopped by collisions with neutral atoms and molecules, primarily oxygen and nitrogen, at altitudes of a few hundreds kilometres down to 80 kilometres. Each collision transfers part of the electron energy to these atmospheric particles. In turn, they get rid of this energy excess by emitting visible emissions in specific wavelength (or colours) such as green (oxygen) or purple (nitrogen).

It has been observed that these electric potential structures are mainly of two types - symmetric (U-shaped) or asymmetric (S-shaped), and typically occur at the boundaries between magnetospheric regions with different properties.

The former type (U-shaped) was found at a plasma boundary between the so-called ‘central plasma sheet’, situated in the magnetotail at equatorial latitudes, and the ‘plasma sheet boundary layer’, an adjacent area located at higher latitudes. The latter type (S-shaped) was found at the boundary between the ‘plasma sheet boundary layer’ and the polar cap, further up in latitude.

Image Credits: ESA
Read more
Cluster – new insights into the electric circuits of polar lights
Auroras: Paintings in the sky from Exploratorium
Looking at exoplanet atmospheres from Centauri Dreams
Magnetic Explosions In The Distant Universe from Science Daily

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Thursday, February 08, 2007

Quantum Light

Physicists at Cambridge MA exhange Light & Matter

For the first time physicisists have stopped and extinguished a light pulse in one part of space and then revived it in a completely separate location. They accomplished this feat by completely converting the light pulse into matter that travels between the two locations and is subsequently changed back to light.

Matter, unlike light, can easily be manipulated, and the experiments provide a powerful means to control optical information. The findings, published this week by Harvard University researchers in the journal Nature, could present an entirely new way for scientists and engineers to manipulate the light pulses used in fiber-optic communications, the technology at the heart of our highly networked society.

"We demonstrate that we can stop a light pulse in a supercooled sodium cloud, store the data contained within it, and totally extinguish it, only to reincarnate the pulse in another cloud two-tenths of a millimeter away," says Lene Hau, Professor of Physics and of Applied Physics in Harvard's Faculty of Arts and Sciences and School of Engineering and Applied Sciences.

Read more on Matter & Light United from Harvard University

Scientists at Harvard University first showed how ultra-cold atoms can be used to freeze and control light to form the "core" – or central processing unit – of an optical computer. Optical computers would transport information ten times faster than traditional electronic devices, smashing the intrinsic speed limit of silicon technology.

This research could be a major breakthrough in the quest to create super-fast computers that use light instead of electrons to process information.

Some substances, like water and diamonds, can slow light to a limited extent. More drastic techniques are needed to dramatically reduce the speed of light. Hau's team accomplished "light magic" by laser-cooling a cigar-shaped cloud of sodium atoms to one-billionth of a degree above absolute zero, the point where scientists believe no further cooling can occur. Using a powerful electromagnet, the researchers suspended the cloud in an ultra-high vacuum chamber, until it formed a frigid, swamp-like goop of atoms.

When they shot a light pulse into the cloud, it bogged down, slowed dramatically, eventually stopped, and turned off. The scientists later revived the light pulse and restored its normal speed by shooting an additional laser beam into the cloud.

Hau's cold-atom research began in the mid-1990s, when she put ultra-cold atoms in such cramped quarters they formed a type of matter called a Bose-Einstein condensate. In this state, atoms behave oddly, and traditional laws of physics do not apply. Instead of bouncing off each other like bumper cars, the atoms join together and function as one entity.

The first slow-light breakthrough for Hau and her colleagues came in March 1998. Later that summer, they successfully slowed a light beam to 38 miles per hour, the speed of suburban traffic. That's 2 million times slower than the speed of light in free space. By tinkering with the system, Hau and her team first made light stop completely in the summer of 2000.

Light waves that travel very slowly without distortion could eventually help simplify and reduce the cost of high-speed optical communications. (Image courtesy of National Institute Of Standards And Technology)

Light is so fast that it takes less than 2 seconds to travel from the Earth to the moon. This blazing fast speed is what makes the Internet and other complex communications systems possible. But sometimes light needs to be slowed down so that signals can be routed in the right direction and order, converted from one form to another or synchronized properly.

Ultraslow Optical Solitons in a Cold Four-State Medium
Physical Review Letters, Vol. 93. Issue 14

NIST physicists showed it is possible to use a very stable pulsed laser to create a soliton that travels slowly through a cryogenic gas of rubidium atoms for more than 5 centimeters without noticeable distortion. The scientists now plan to translate the theory into practical experiments. Currently, 300 kilometers of fiber are required to delay an optical signal for one thousandth of a second, whereas only a few centimeters of fiber might be needed using the new class of soliton.

Solitons first were discovered in the 1800s when a naval engineer observed a water wave travel more than a mile within a canal without dissipating. Light wave solitons generated within optical fibers are now the subject of intense research worldwide. Their very short, stable pulse shapes might be used to pack more information into fiber-optic communication systems. But when previously known forms of optical solitons are slowed down, attenuations and distortions (and therefore losses of data) occur quickly, before the light has travelled even 1 millimeter.
Magsails on the Solar Wind? by Centauri Dreams
Measurements Recast Usual View Of Elusive Force from Science Daily
Towards Quantum Computing: Artificial Atoms Make Microwave Photons Countable

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Monday, February 05, 2007

Extra Spatial Dimensions


Physicists at the University of Wisconsin-Madison have devised an approach that may help unlock the hidden shapes of alternate dimensions of the universe.

A new study demonstrates that the shapes of extra dimensions can be "seen" by deciphering their influence on cosmic energy released by the violent birth of the universe 13 billion years ago. The method, published 02/02/07 in Physical Review Letters, provides evidence that physicists can use experimental data to discern the nature of these elusive dimensions.

String theory, proposes that everything in the universe is made of tiny, vibrating strings of energy, to encompass the physical principles of all objects from immense galaxies to subatomic particles. Though currently the front-runner to explain the framework of the cosmos, the theory remains, to date, untested.

The mathematics of string theory suggests that the world we know is not complete. In addition to our four familiar dimensions (three-dimensional space and time) string theory predicts the existence of six extra spatial "hidden" dimensions curled in tiny geometric shapes at every single point in our universe.

Maybe you can't picture a 10-dimensional world. Our minds are accustomed to only three spatial dimensions and lack a frame of reference for the other six, says UW-Madison physicist Gary Shiu, who led the new study. Though scientists use computers to visualize what these six-dimensional geometries could look like (see image), no one really knows for sure what shape they take.

A computer-generated rendering of a possible six-dimensional geometry similar to those studied by UW-Madison physicist Gary Shiu. (Image: courtesy Andrew J. Hanson, Indiana University)

According to string theory mathematics, the extra dimensions could adopt any of tens of thousands of possible shapes, each shape theoretically corresponding to its own universe with its own set of physical laws. For our universe, Nature picked one.

The many-dimensional shapes are far too small to see or measure through any usual means of observation, which makes testing this crucial aspect of string theory very difficult.

Just as a shadow can give an idea of the shape of an object, the pattern of cosmic energy in the sky can give an indication of the shape of the other six dimensions present, Shiu explains.

To learn how to read telltale signs of the six-dimensional geometry from the cosmic map, they worked backward. Starting with two different types of mathematically simple geometries, called warped throats, they calculated the predicted energy map that would be seen in the universe described by each shape. When they compared the two maps, they found small but significant differences between them.

The results show that specific patterns of cosmic energy can hold clues to the geometry of the six-dimensional shape.

Story adapted from a news release by University of Wisconsin-Madison
more Physicists Find Way To 'See' Extra Dimensions from Science Daily
Calabi Yau from WMAP by Lubos Motl
Symmetry in psychological action by Plato

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Sunday, February 04, 2007

Thor's Helmet

Credit & Copyright: Jean-Charles Cuillandre (CFHT), Hawaiian Starlight, CFHT

NGC 2359 is a striking emission nebula with an impressive popular name - Thor's Helmet Sure, its suggestive winged appearance might lead some to refer to it as the "duck nebula", but if you were a nebula which name would you choose? By any name NGC 2359 is a bubble-like nebula some 30 light-years across, blown by energetic winds from an extremely hot star seen near the center and classified as a Wolf-Rayet star. Wolf-Rayet stars are rare massive blue giants which develop stellar winds with speeds of millions of kilometers per hour. Interactions with a nearby large molecular cloud are thought to have contributed to this nebula's more complex shape and curved bow-shock structures. NGC 2359 is about 15,000 light-years distant toward the constellation Canis Major.

Discover the Universe with APoD - Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
Gliese 710 - A Red Dwarf Star heading our way by Astroprof
Famous Quotes: Man - a being in search of meaning. Plato

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Saturday, February 03, 2007

The Moon & TIME

La Luna - copyright - 2005 Jerry Lodriguss

The Moon makes a complete orbit about the Earth with respect to the fixed stars (its sidereal period) approximately once every 27.3 days. However, since the Earth is moving in its orbit about the Sun at the same time, it takes slightly longer for the Moon to show its same phase to Earth, which is about 29.5 days (its synodic period). Unlike most satellites of other planets, the Moon orbits near the ecliptic and not the Earth's equatorial plane.

Most of the tidal effects seen on the Earth are caused by the Moon's gravitational pull, with the Sun making only a small contribution. Tidal effects result in an increase of the mean Earth-Moon distance of about 4 meters per century, or 4 centimetres per year. As a result of the conservation of angular momentum, the increasing semimajor axis of the Moon is accompanied by a gradual slowing of the Earth's rotation by about 0.002 seconds per day per century

How Does Your Brain Tell Time? Study Challenges Theory Of Inner Clock

For decades, scientists have believed that the brain possesses an internal clock that allows it to keep track of time.

The changing colours reflect how a brain cell network evolves over time in response to stimuli. (Credit: Buonomano Lab)

Now a UCLA study in the Feb. 1 edition of Neuron proposes a new model in which a series of physical changes to the brain's cells helps the organ to monitor the passage of time.

The most popular theory assumes that a clock-like mechanism -- which generates and counts regular fixed movements -- underlies timing in the brain. In contrast, Buonomano suggests a physical model that operates without using a clock. He offers an analogy to explain how it works.

"If you toss a pebble into a lake," he explained, "the ripples of water produced by the pebble's impact act like a signature of the pebble's entry time. The farther the ripples travel the more time has passed.

"We propose that a similar process takes place in the brain that allows it to track time," he added. "Every time the brain processes a sensory event, such as a sound or flash of light, it triggers a cascade of reactions between brain cells and their connections. Each reaction leaves a signature that enables the brain-cell network to encode time."

The UCLA team used a computer model to test this theory. By simulating a network of interconnected brain cells in which each connection changed over time in response to stimuli, they were able to show that the network could tell time.

Their simulations indicated that a specific event is encoded within the context of events that precede it. In other words, if one could measure the response of many neurons in the brain to a tone or a flash of light, the response would not only reveal the nature of the event, but the other events that preceded it and when they occurred.

Note: This story has been adapted from a news release
issued by
University of California - Los Angeles.

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Thursday, February 01, 2007

ESA Space Propulsion

Credits: ESA - AOES Medialab

How SMART-1 has made European space exploration smarter
A unique way to travel to the Moon, new technologies successfully tested and brand-new science: a few months after the end of the SMART-1 mission scientists and engineers gathered to recap on these and all the other achievements of the first European mission to the Moon.

The innovative SMART-1 Moon mission has taught ESA, European space industry and institutes a lot about how to perform its missions even more efficiently. For example, the operational tools developed and the lessons learned are already being used on ESA missions such as Rosetta and Venus Express. The SMART-1 experience has also been used to prepare future ESA missions, such as Bepi-Colombo, which will visit the inner planet Mercury.

Credits: AOES Medialab, ESA 2002.

SMART-1 first orbits the Earth in ever-increasing ellipses. When it reaches the Moon, its orbit is altered by the Moon's gravitational field. It uses a number of these lunar 'gravity assist' manoeuvres to position itself for entering orbit around the Moon.

Using electric propulsion, ESA can send Bepi-Colombo to Mercury in just six years, whereas traditional rockets would take at least seven. Electric propulsion will also be able to transport much more scientific equipment to Mercury than a traditional spacecraft. With SMART-1, we learned how to drive an electric propulsion spacecraft.

Read More ESA Press Release 31/01/2007
Talking with the Planets by Astroprof
Cassini images mammoth cloud engulfing Titan’s North Pole from ESA

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