[time-cop]

well mr hubble aint so clever,he missed out m3227895beta a small binary star to the right of ngc285,  naaah im talking tosh,ace piccy tho [8D]

http://www.armybarmy.org

[neilep]

XMM-Newton observes fossil galaxy cluster


XMM-Newton observations of the fossil
galaxy cluster RX J1416.5+2315, show a cloud of hot gas emitting X-rays (in
blue). The cloud, reaching temperatures of about 50 million degrees, extend
over 3.5 million light years and surround a giant elliptical galaxy believed to
have grown to its present size by cannibalising its neighbours.

Credit: Credits: Khosroshahi, Maughan,
Ponman, Jones, ESA, ING




 
Taking advantage of the high sensitivity of ESA's XMM-Newton and the sharp vision of NASA's Chandra X-Ray space observatories, astronomers have studied the behaviour of massive fossil galaxy clusters, trying to find out how they find the time to form…
Many galaxies reside in galaxy groups, where they experience close encounters with their neighbours and interact gravitationally with the dark matter - mass which permeates the whole intergalactic space but is not directly visible because it doesn't emit radiation. These interactions cause large galaxies to spiral slowly towards the centre of the group, where they can merge to form a single giant central galaxy, which progressively swallows all its neighbours.

If this process runs to completion, and no new galaxies fall into the group, then the result is an object dubbed a 'fossil group', in which almost all the stars are collected into a single giant galaxy, which sits at the centre of a group-sized dark matter halo. The presence of this halo can be inferred from the presence of extensive hot gas, which fills the gravitational potential wells of many groups and emits X-rays.

A group of international astronomers studied in detail the physical features of the most massive and hot known fossil group, with the main aim to solve a puzzle and understand the formation of massive fossils. In fact, according to simple theoretical models, they simply could not have formed in the time available to them!

The fossil group investigated, called 'RX J1416.4+2315', is dominated by a single elliptical galaxy located one and a half thousand million light years away from us, and it is 500 thousand million times more luminous than the Sun.

The XMM-Newton and Chandra X-ray observations, combined with optical and infrared analyses, revealed that group sits within a hot gas halo extending over three million light years and heated to a temperature of 50 million degrees, mainly due to shock heating as a result of gravitational collapse.

Such a high temperature, about as twice as the previously estimated values, is usually characteristic of galaxy clusters. Another interesting feature of the whole cluster system is its large mass, reaching over 300 trillion solar masses. Only about two percent of it in the form of stars in galaxies, and 15 percent in the form of hot gas emitting X-rays. The major contributor to the mass of the system is the invisible dark matter, which gravitationally binds the other components.

According to calculations, a fossil cluster as massive as RX J1416.4+2315 would have not had the time to form during the whole age of the universe. The key process in the formation of such fossil groups is the process known as 'dynamical friction', whereby a large galaxy loses its orbital energy to the surrounding dark matter. This process is less effective when galaxies are moving more quickly, which they do in massive 'clusters' of galaxies.

This, in principle, sets an upper limit to the size and mass of fossil groups. The exact limits are, however, still unknown since the geometry and mass distribution of groups may differ from that assumed in simple theoretical models.

"Simple models to describe the dynamical friction assume that the merging galaxies move along circular orbits around the centre of the cluster mass", says Habib Khosroshahi from the University of Birmingham (UK), first author of the results. "Instead, if we assume that galaxies fall towards the centre of the developing cluster in an asymmetric way, such as along a filament, the dynamic friction and so the cluster formation process may occur in a shorter time scale," he continues. Such a hypothesis is supported by the highly elongated X-ray emission we observed in RX J1416.4+2315, to sustain the idea of a collapse along a dominant filament."

The optical brightness of the central dominant galaxy in this fossil is similar to that of brightest galaxies in large clusters (called 'BCGs'). According to the astronomers, this implies that such galaxies could have originated in fossil groups around which the cluster builds up later. This offers an alternative mechanism for the formation of BCGs compared to the existing scenarios in which BCGs form within clusters during or after the cluster collapse.

"The study of massive fossil groups such as RX J1416.4+2315 is important to test our understanding of the formation of structure in the universe," adds Khosroshahi. "Cosmological simulations are underway which attempt to reproduce the properties we observe, in order to understand how these extreme systems develop," he concludes.

SOURCE: EUREKALERT

Men are the same as women, just inside out !

[neilep]

Evolutionary Back Story: Thoroughly modern spine supported human ancestor
Bruce Bower

Bones from a spinal column discovered at a nearly 1.8-million-year-old site in central Asia support the controversial possibility that ancient human ancestors spoke to one another.




WIDE OPEN. A recently discovered Homo erectus vertebra
from central Asia (left) displays a larger spinal cord canal than does
 a corresponding bone (right) from a skeleton that had been found in
Kenya.

Meyer


Excavations in 2005 at Dmanisi, Georgia, yielded five vertebrae from a Homo erectus individual, says anthropologist Marc R. Meyer of the University of Pennsylvania in Philadelphia. The finds occurred in previously dated sediment that has yielded several skulls now attributed to H. erectusThe new discoveries represent the oldest known vertebrae for the genus Homo, Meyer announced last week at the annual meeting of the Paleoanthropology Society in San Juan, Puerto Rico. The fossils consist of one lumbar, two thoracic, and two cervical vertebrae.

Meyer and his colleagues—David Lordkipanidze and Abesalom Vekua, both of the Georgian State Museum in Tbilisi—compared the size, shape, and volume of the Dmanisi vertebrae with more than 2,200 corresponding bones from people, chimpanzees, and gorillas.

"The Dmanisi spinal column falls within the human range and would have comfortably accommodated a modern human spinal cord," Meyer says.

Moreover, the fossil vertebrae would have provided ample structural support for the respiratory muscles needed to articulate words, he asserts. Although it's impossible to confirm that our prehistoric ancestors talked, Meyer notes, H. erectus at Dmanisi faced no respiratory limitations on speech.

In contrast, the 1984 discovery in Kenya of a boy's 1.6-million-year-old skeleton, identified by some researchers as H. erectus and by others as Homo ergaster, yielded small, chimplike vertebrae. Researchers initially suspected that the ancient youth and his presumably small-spined comrades lacked the respiratory control to talk as people do today.

In the past 5 years, investigators including Bruce Latimer of the Cleveland Museum of Natural History have suggested that the prehistoric boy offers a misleading view of H. erectus' backbone. They contend that growth of the bony canal encasing his spinal cord had been stunted, and spinal cord compression would have impeded his movement and caused limb weakness.

Finding ancient, humanlike vertebrae at Dmanisi fits with Latimer's view, Meyer says. Infant malnutrition, which often arrests growth of the human vertebral canal, may have affected the H. erectus youth, Meyer suggests.

The ancient boy, who died at age 10 or so, would have required intensive protection and provisioning, Meyer asserts. "Both altruism and spoken language may have been part of the behavioral repertoire of early Homo," the Pennsylvania researcher says.

The modern-looking vertebrae at Dmanisi, remarks David Frayer of the University of Kansas in Lawrence, comport with earlier fossil-skull studies indicating that early Homo possessed a speech-ready vocal tract.

Robert C. McCarthy of Florida Atlantic University in Boca Raton disagrees. At the Paleoanthropology Society meeting, he presented vocal-tract reconstructions for various ancient Homo species suggesting that the capacity to articulate speech as well as people do now emerged exclusively in Homo sapiens around 50,000 years ago.

Before then, all members of the Homo genus—including H. sapiens—possessed a short set of neck vertebrae, resulting in a vocal tract with a restricted range of speech sounds, McCarthy and his coworkers argue.

Many populations today, including Australian aborigines, possess neck vertebrae comparable in length to those that McCarthy's team considered inadequate for modern speech, Meyer responds.


SOURCE:SCIENCENEWS.COM

Men are the same as women, just inside out !

[neilep]

The record of Rhea
CASSINI PHOTO RELEASE
Posted: May 14, 2006



Credit: NASA/JPL/Space Science Institute
Download larger image versionhere


Cassini looks down upon Rhea, whose cratered surface was already ancient before any complex life developed on Earth. The terrain seen here has probably changed little in the past billion years.

This view shows terrain on the Saturn-facing hemisphere of Rhea (1,528 kilometers, or 949 miles across). North is up.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera at a distance of approximately 94,000 kilometers (59,000 miles) from Rhea and at a Sun-Rhea-spacecraft, or phase, angle of 109 degrees. Image scale is 558 meters (1,832 feet) per pixel.

SPACEFLIGHTNOW.COM

Men are the same as women, just inside out !

[neilep]

Dwarfs gave way to giants
HARVARD-SMITHSONIAN CENTER FOR ASTROPHYSICS NEWS RELEASE
Posted: May 17, 2006

The first galaxies were small - about 10,000 times less massive than the Milky
 Way. Billions of years ago, those mini-furnaces forged a multitude of hot,
massive stars. In the process, they sowed the seeds for their own
destruction by bathing the universe in ultraviolet radiation. According to
theory, that radiation shut off further dwarf galaxy formation by both ionizing
 and heating surrounding hydrogen gas. Now, astronomers Stuart Wyithe
(University of Melbourne) and Avi Loeb (Harvard-Smithsonian Center for
Astrophysics) are presenting direct evidence in support of this theory.



This artist's conception shows a collection of hot, blue stars
comprising an early dwarf galaxy surrounded by red hydrogen gas. Credit:
David A. Aguilar (CfA)
 
 
Wyithe and Loeb showed that fewer, larger galaxies, rather than more
numerous, smaller galaxies, dominated the billion-year-old universe. Dwarf
galaxy formation essentially shut off only a few hundred million years after the
 Big Bang.


"The first dwarf galaxies sabotaged their own growth and that of their
siblings," says Loeb. "This was theoretically expected, but we identified the
first observational evidence for the self-destructive behavior of early
galaxies."

Their research is being reported in the May 18, 2006 issue of Nature.


Nearly 14 billion years ago, the Big Bang filled the universe with hot matter in
the form of electrons and hydrogen and helium ions. As space expanded and
cooled, electrons and ions combined to form neutral atoms. Those atoms
efficiently absorbed light, yielding a pervasive dark fog throughout space.
Astronomers have dubbed this era the "Dark Ages."


The first generation of stars began clearing that fog by bathing the universe
in ultraviolet radiation. UV radiation splits atoms into negatively charged
electrons and positively charged ions in a process called ionization. Since the
 Big Bang created an ionized universe that later became neutral, this second
phase of ionization by stars is known as the "epoch of reionization." It took
place in the first few hundred million years of existence.


"We want to study this time period because that's when the primordial soup
evolved into the rich zoo of objects we now see," said Loeb.


During this key epoch in the history of the universe, gas was not only ionized
, but also heated. While cool gas easily clumps together to form stars and
galaxies, hot gas refuses to be constrained. The hotter the gas, the more
massive a galactic "seed" must be to attract enough matter to become a
galaxy.


Before the epoch of reionization, galaxies containing only 100 million solar
masses of material could form easily. After the epoch of reionization, galaxies
required more than 10 billion solar masses of material to be assembled.


To determine typical galaxy masses, Wyithe and Loeb looked at light from
quasars - powerful light sources visible across vast distances. The light from
 the farthest known quasars left them nearly 13 billion years ago, when the
universe was a fraction of its present age. Quasar light is absorbed by
intervening clouds of hydrogen associated with early galaxies, leaving telltale
 bumps and wiggles in the quasar's spectrum.

By comparing the spectra of different quasars along different lines of sight,
Wyithe and Loeb determined typical galaxy sizes in the infant universe. The
presence of fewer, larger galaxies leads to more variation in the absorption
seen along various lines of sight. Statistically, large variation is exactly what
 Wyithe and Loeb found.

"As an analogy, suppose you are in a room where everybody is talking,"
explains Wyithe. "If this room is sparsely populated, then the background
noise is louder in some parts of the room than others. However if the room is
 crowded, then the background noise is the same everywhere. The fact that
we see fluctuations in the light from quasars implies that the early universe
was more like the sparse room than the crowded room."


Astronomers hope to confirm the suppression of dwarf galaxy formation using
the next generation of telescopes - both radio telescopes that can detect
distant hydrogen and infrared telescopes that can directly image young
galaxies. Within the next decade, researchers using these new instruments
will illuminate the "Dark Ages" of the universe.


Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for
Astrophysics (CfA) is a joint collaboration between the Smithsonian
Astrophysical Observatory and the Harvard College Observatory. CfA
scientists, organized into six research divisions, study the origin, evolution
and ultimate fate of the universe.

SOURCE: SPACEFLIGHTNOW.COM

Men are the same as women, just inside out !

[neilep]

Hubble captures a 'five-star' rated gravitational lens
HUBBLE EUROPEAN SPACE AGENCY INFORMATION CENTRE NEWS RELEASE
Posted: May 22, 2006

The Hubble Space Telescope has captured the first-ever picture of a distant quasar lensed into five images. In addition, the image holds a treasure of lensed galaxies and even a supernova.


Credit: ESA, NASA, K. Sharon (Tel Aviv University) and E. Ofek (Caltech)
Download larger image version here
 
 
The most unique feature in a new image taken with the NASA/ESA Hubble Space Telescope is a group of five quasar images produced by a process called gravitational lensing, in which the gravitational field of a massive object - in this case, a cluster of galaxies - bends and amplifies light from an object - in this case, a quasar - farther behind it.

Although other multiply lensed quasars have been seen before this newly observed ³quintuple quasar² is the only case so far in which multiple quasar images are produced by an entire galaxy cluster acting as a gravitational lens.

The background quasar is the brilliant core of a galaxy. It is powered by a black hole, which is devouring gas and dust and creating a gusher of light in the process. When the quasar's light passes through the gravity field of the galaxy cluster that lies between us and the quasar, the light is bent by the space-warping gravity field in such a way that five separate images of the object are produced surrounding the cluster's centre. The fifth quasar image is embedded to the right of the core of the central galaxy in the cluster. The cluster also creates a cobweb of images of other distant galaxies gravitationally lensed into arcs.

The galaxy cluster creating the lens is known as SDSS J1004+4112 and was discovered as part of the Sloan Digital Sky Survey. It is one of the more distant clusters known (seven billion light-years, redshift z=0.68), and is seen when the Universe was half its present age.

Gravitational lensing occurs for extremely concentrated masses like the cores of galaxies or galaxy clusters. Their strong gravity warps the surrounding space, and light travelling through that warped space bends its direction. Multiple images of a distant light source may be seen, each taking a different path through the warped space.



Credit: ESA, NASA, K. Sharon (Tel Aviv University) and E. Ofek (Caltech)
 
 
A gravitational lens will always produce an odd number of lensed images, but one image is usually very weak and embedded deep within the light of the lensing object itself. Though previous observations of SDSS J1004+4112 have revealed four of the images of this system, Hubble's sharp vision and the high magnification of this gravitational lens combine to place a fifth image far enough from the core of the central imaging galaxy to make it visible as well.

The galaxy hosting the background quasar is at a distance of 10 billion light years (at redshift 1.74). The quasar host galaxy can be seen in the image as faint red arcs. This is the most highly magnified quasar host galaxy ever seen.

The Hubble picture also shows a large number of stretched arcs that are more distant galaxies lying behind the cluster, each of which is split into multiple distorted images. The most distant galaxy identified and confirmed so far is 12 billion light years away (a redshift of 3.33, corresponding to only 1.8 billion years after the Big Bang).

By comparing this image to a picture of the cluster obtained with Hubble a year earlier, the researchers discovered a rare event - a supernova exploding in one of the cluster galaxies. This supernova exploded seven billion years ago, and the data, together with other supernova observations, are being used to try to reconstruct how the Universe was enriched by heavy elements through these explosions.

SOURCE;SPACEFLIGHTNOW.COM



Men are the same as women, just inside out !

[neilep]

A new ruler available to measure the universe
LAWRENCE BERKELEY NATIONAL LABORATORY NEWS RELEASE
Posted: May 22, 2006

A team of astronomers led by Nikhil Padmanabhan and David Schlegel has published the largest three-dimensional map of the universe ever constructed, a wedge-shaped slice of the cosmos that spans a tenth of the northern sky, encompasses 600,000 uniquely luminous red galaxies, and extends 5.6 billion light-years deep into space, equivalent to 40 percent of the way back in time to the Big Bang.



A schematic view of the new SDSS three-dimensional map,
which includes regular galaxies (black points) and luminous red
galaxies (red points) and extends 5.6 billion light-years, 40
percent of the distance to the edge of the visible universe. Credit:
LBNL
 

Schlegel is a Divisional Fellow in the Physics Division of Lawrence Berkeley National Laboratory, and Padmanabhan will join the Lab's Physics Division as a Chamberlain Fellow and Hubble Fellow in September; presently he is at Princeton University. They and their coauthors are members of the Sloan Digital Sky Survey (SDSS), and have previously produced smaller 3-D maps by using the SDSS telescope in New Mexico to painstakingly collect the spectra of individual galaxies and calculate their distances by measuring their redshifts.

"What's new about this map is that it's the largest ever," says Padmanabhan, "and it doesn't depend on individual spectra."

The principal motive for creating large-scale 3-D maps is to understand how matter is distributed in the universe, says Padmanabhan. "The brightest galaxies are like lighthouses -- where the light is, is where the matter is."

Schlegel says that "because this map covers much larger distances than previous maps, it allows us to measure structures as big as a billion light-years across."

A natural ruler in space

The variations in galactic distribution that constitute visible large-scale structures are directly descended from variations in the temperature of the cosmic microwave background, reflecting oscillations in the dense early universe that have been measured to great accuracy by balloon-borne experiments and the WMAP satellite.

The result is a natural "ruler" formed by the regular variations (sometimes called "baryon oscillations," with baryons as shorthand for ordinary matter), which repeat at intervals of some 450 million light-years.

"Unfortunately it's an inconveniently sized ruler," says Schlegel. "We had to sample a huge volume of the universe just to fit the ruler inside."

Says Padmanabhan, "Although the universe is 13.7 billion years old, that really isn't a whole lot of time when you're measuring with a ruler that's marked only every 450 million light-years."

The distribution of galaxies reveals many things, but one of the most important is a measure of the mysterious dark energy that accounts for some three-fourths of the universe's density. (Dark matter accounts for roughly another 20 percent, while less than 5 percent is ordinary matter of the kind that makes visible galaxies.)

"Dark energy is just the term we use for our observation that the expansion of the universe is accelerating," Padmanabhan remarks. "By looking at where density variations were at the time of the cosmic microwave background" -- only about 300,000 years after the Big Bang -- "and seeing how they evolve into a map that covers the last 5.6 billion years, we can see if our estimates of dark energy are correct."

The new map shows that the large-scale structures are indeed distributed the way current ideas about the accelerating expansion of the universe would suggest. The map's assumed distribution of dark matter, which although invisible is affected by gravity just like ordinary matter, also conforms to current understanding.

Dead, red galaxies

What made the big new 3-D map possible were the Sloan Digital Sky Survey's wide-field telescope, which covers a three-degree field of view (the full moon is about half a degree), plus the choice of a particular kind of galactic "lighthouse," or distance marker: luminous red galaxies.

"These are dead, red galaxies, some of the oldest in the universe -- in which all the fast-burning stars have long ago burned out and only old red stars are left," says Schlegel. "Not only are these the reddest galaxies, they're also the brightest, visible at great distances."

The Sloan Digital Sky Survey astronomers worked with colleagues on the Australian Two-Degree Field team to average the color and redshift of a sample of 10,000 red luminous galaxies, relating galaxy color to distance. They then applied these measurements to 600,000 such galaxies to plot their map.

Padmanabhan concedes that "there's statistical uncertainty in applying a brightness-distance relation derived from 10,000 red luminous galaxies to all 600,000 without measuring them individually. The game we play is, we have so many that the averages still give us very useful information about their distribution. And without having to measure their spectra, we can look much deeper into space."

Schlegel agrees that the researchers are far from achieving the precision they want. "But we have shown that such measurements are possible, and we have established the starting point for a standard ruler of the evolving universe."

He says "the next step is to design a precision experiment, perhaps based on modifications to the SDSS telescope. We are working with engineers here at Berkeley Lab to redesign the telescope to do what we want to do."

"The Clustering of Luminous Red Galaxies in the Sloan Digital Sky Survey Imaging Data," by Nikhil Padmanabhan, David J. Schlegel, Uros Seljak, Alexey Makarov, Neta A. Bahcall, Michael R. Blanton, Jonathan Brinkmann, Daniel J. Eisenstein, Douglas P. Finkbeiner, James E. Gunn, David W. Hogg, Zeljko Ivezic', Gillian R. Knapp, Jon Loveday, Robert H. Lupton, Robert C. Nichol, Donald P. Schneider, Michael A. Strauss, Max Tegmark, and Donald G. York, will appear in the Monthly Notices of the Royal Astronomical Society

SOURCE: SPACEFLIGHTNOW.COM


Men are the same as women, just inside out !

[neilep]

Underwater Hotel

Currently under construction in Dubai, Hydropolis is the world's
first underwater luxury hotel. It will include three elements: the
land station, where guests will be welcomed, the connecting tunnel,
which will transport people by train to the main area of the hotel,
and the 220 suites within the submarine leisure complex.

This will be a hotel where those who do not dive - or do not even
swim - can experience the tranquillity and inspiration of the
underwater world.




In order to enter this surreal space, visitors will begin at the
 land station. This 120m woven, semicircular cylinder will arch over
a multi-storey building.






The upper storeys of the land station house a variety of facilities,
including a cosmetic surgical clinic, a marine biological research
laboratory and conference facilities.




The world of science fiction becoming reality.





SOURCE: http://www.alltraveltips.com/underwaterhotel.html



Men are the same as women, just inside out !

[neilep]

Crunch time for Planet Pluto  
By Nicola Cook
BBC Horizon  


Pluto moves from 30 to 50 times the Sun-Earth distance over its 248-
year orbit. It has two moons in addition to Charon (the smaller
object pictured here). The gravity on Pluto is about 6% of Earth's;
the surface temperature -233C.


 
At its conference this August, the International Astronomical Union (IAU) will make a decision that could see Pluto lose its status as a planet.

For the first time, the organisation will be officially defining the word "planet", and it is causing much debate in the world of astronomy.

There is only one thing that everyone seems to agree on: there are no longer nine planets in the Solar System.

Matters were brought to a head by the discovery in January of last year of a potential 10th planet, temporarily named 2003 UB313.

Professor Mike Brown and his team at the California Institute of Technology have already discovered several large objects on the edge of the Solar System, but 2003 UB313 is special because it is bigger than Pluto.

The question now facing the IAU is whether to make this new discovery a planet.

Pressing issue

Co-discoverer Dr Chad Trujillo thinks the solution is pretty straightforward.

"The logically consistent thing would be to either have 2003 UB313 a planet, and Pluto be a planet; or have neither be a planet," he told the BBC's Horizon programme.

But Pluto is already an unusual planet. It is made predominantly of ice, and is smaller even than the Earth's Moon.

 



In 1992, Professor Dave Jewitt and Dr Jane Lu at the University of Hawaii discovered a new collection of objects beyond Neptune called the Kuiper Belt. Some suggest Pluto should no longer be considered a planet, but a Kuiper Belt Object.

As Professor Jewitt says: "We always say we found plus one Kuiper Belt, and minus one planet. And the one we lost, of course, is Pluto."

There are many astronomers who agree with Dave Jewitt and would opt for an eight-planet Solar System, with neither Pluto or 2003 UB313 making the grade; but a number of astronomers are arguing for a more specific definition of a planet.

Kuiper Belt researcher Dr Marc Buie, of the Lowell Observatory in Arizona, has come up with a clear planetary definition he would like to see the IAU adopt.

Different categories

"I believe the definition of planet should be as simple as possible, so I've come up with two criteria," he said.

"One is that it can't be big enough to burn its own matter - that's what a star does. On the small end, I think the boundary between a planet and not a planet should be, is the gravity of the object stronger than the strength of the material of the object? That's a fancy way of saying is it round?"

 

This definition could lead to a Solar System with as many as 20 planets, including Pluto, 2003 UB313, and many objects previously classified as moons or asteroids.

One possible resolution to the debate is for new categories of planet to be introduced. Mercury, Venus, the Earth and Mars would be "rocky planets". The gas-giants Jupiter, Saturn, Uranus and Neptune would be a second category.

Pluto, 2003 UB313, and any other objects passing the "roundness test", would be reclassified as a third type of planet - perhaps "icy dwarfs".

Whatever the final outcome, by September there will no longer be nine planets in the Solar System.



Bye-Bye Planet Pluto is broadcast on BBC Two at 2100 BST this Thursday, 22 June
 


SOURCE: BBC.CO.UK

Men are the same as women, just inside out !

[neilep]

Hubble reveals two dust disks around nearby star
SPACE TELESCOPE SCIENCE INSTITUTE NEWS RELEASE
Posted: June 28, 2006

Detailed images of the nearby star Beta Pictoris, taken by NASA's Hubble Space Telescope, confirm the existence of not one but two dust disks encircling the star. The images offer tantalizing new evidence for at least one Jupiter-size planet orbiting Beta Pictoris.



Larger versionHERE


The finding ends a decade of speculation that an odd warp in the young star's debris disk may actually be another inclined disk. The recent Hubble Advanced Camera for Surveys view ­ the best visible-light image of Beta Pictoris ­ clearly shows a distinct secondary disk that is tilted by about 4 degrees from the main disk. The secondary disk is visible out to roughly 24 billion miles from the star, and probably extends even farther, said astronomers.

The finding, by a team of astronomers led by David Golimowski of Johns Hopkins University in Baltimore, Md., appears in the June 2006 issue of the Astronomical Journal. To see the faint disk, astronomers used the Advanced Camera for Surveys' coronagraph, which blocked the light from Beta Pictoris. The disk is fainter than the star because its dust only reflects light.

The best explanation for the observations is that a suspected unseen planet, about one to 20 times the mass of Jupiter and in an orbit within the secondary disk, is using gravity to sweep up material from the primary disk.

"The Hubble observation shows that it is not simply a warp but two concentrations of dust in two separate disks," Golimowski said. "The finding suggests that planetary systems could be forming in two different planes. We know this can happen because the planets in our solar system are typically inclined to Earth's orbit by several degrees. Perhaps stars forming more than one dust disk may be the norm in the formative years of a star system."

Dynamical computer models by David Mouillet and Jean-Charles Augereau of Grenoble Observatory in France suggest how a secondary dust disk can form. A planet in an inclined orbit gravitationally attracts small bodies of rock and/or ice, called planetesimals, from the main disk, and moves them into an orbit aligned with that of the planet. These perturbed planetesimals then collide with each other, producing the tilted dust disk seen in the new Hubble images.

Astronomers do not know how the planet, if it exists, settled into an inclined orbit. However, computer simulations by multiple research teams show that planet embryos which start out in a very thin plane, can, through gravitation interactions, rapidly scatter into orbits that become inclined to the primary disk. Whatever the process, the four degree inclination of the suspected perturbing planet in Beta Pictoris is not unlike the several degree spread seen in our solar system.

"The actual lifetime of a dust grain is relatively short, maybe a few hundred thousand years," Golimowski explained. "So the fact that we can still see these disks around a 10- to 20-million-year-old star means that the dust is being replenished by collisions between planetesimals."

Beta Pictoris is located 63 light-years away in the southern constellation Pictor. Although the star is much younger than the Sun, it is twice as massive and nine times more luminous. Beta Pictoris entered the limelight over 20 years ago when NASA's Infrared Astronomical Satellite detected excess infrared radiation from the star. Astronomers attributed this excess to the presence of warm circumstellar dust.

The dust disk was first imaged by ground-based telescopes in 1984. Those images showed that the disk is seen nearly edge-on from Earth. Hubble observations in 1995 revealed an apparent warp in the disk.

Subsequent images obtained in 2000 by Hubble's Space Telescope Imaging Spectrograph confirmed the warp. The latter study was led by Sara Heap of NASA's Goddard Space Flight Center in Greenbelt, Md. At that time, Heap and her colleagues suggested that the warp may be a secondary disk tilted about 4 degrees from the main disk. Several teams of astronomers attributed the warp to a planet in a tilted orbit out of the plane of the main disk.

Astronomers using ground-based telescopes also found various asymmetries in the star's disk. Infrared images taken in 2002 by the Keck II Observatory in Hawaii showed that another, smaller inner disk may exist around the star in a region the size of our solar system. Golimowski's team did not spot the disk because it is small and is blocked by the Advanced Camera's coronagraph. This possible inner disk is tilted in the opposite direction from the disk seen in the new Hubble images. This misalignment implies that the tilted disks are not directly related. Nevertheless, they both may bolster evidence for the existence of one or more planets orbiting the star.

SOURCE: SPACEFLIGHTNOW.COM



Men are the same as women, just inside out !

[neilep]

FSU Etruscan expert announces historic discovery at ancient site

Tallahassee, Fla. -- Digging on a remote hilltop in Italy, a Florida State University classics professor and her students have unearthed artifacts that dramatically reshape our knowledge of the religious practices of an ancient people, the Etruscans.




View of the Etruscan site at Cetamura, with a rock platform hypothesized to be an Etruscan altar of the second century BCE.




"We are excavating a monumental Etruscan building evidently dating to the final years of Etruscan civilization," said Nancy Thomson de Grummond, the M. Lynette Thompson Professor of Classics at FSU and director of the university's archaeology programs in Italy. Within the building, de Grummond's team located in early June what appears to be a sacrificial pit and a sanctuary -- finds remarkable for the wealth of items they are yielding that appear to have been used in religious rituals.

Nearly every summer since 1983, de Grummond has taken groups of FSU students into Italy's Tuscany region to participate in archaeological digs at Cetamura del Chianti, a site once inhabited by the Etruscans and ancient Romans. In the final days of this year's program, de Grummond and her students unearthed what she calls "the most thrilling" find she has seen in 23 years at Cetamura.

She explained that the Etruscans, who once ruled most of the Italian peninsula, were conquered and absorbed by the Romans in the second and first centuries B.C.E. ("Before the Common Era"). Prior to that time, however, they were a highly advanced civilization that constructed roads, buildings and sewer systems and developed the first true cities in Europe. They also built large, complex religious sanctuaries -- which may have been the purpose served, in part, by the Cetamura structure.

"The building has a highly irregular plan, with stone foundations 3 or 4 feet thick," she said. "One wing of the building is about 60 feet long, flanking a space that has walls running at right angles. Some walls run on a diagonal to the grid, or are curved. There are paved areas alternating with beaten earth floors and what I believe to be a large courtyard in the middle. Some of the foundations are so heavy and thick that they could easily have supported multistoried elements.


Etruscan potsherd with an incised inscription with the name of the god Lurs, worshipped at Cetamura.


Within the building's courtyard, de Grummond said, is a freestanding sandstone platform that likely served as an altar. A few feet away, she and her students unearthed "the most fascinating find of all -- a pit filled with burnt offerings for the gods.

"In all, the pit contained approximately 10 vessels, some miniature and thus clearly intended only as gifts for the gods," de Grummond said. "On the other hand, several of the vessels were quite large, including one storage vessel, probably for grain, and a huge pitcher, probably for wine. There also were little cups for drinking and a bowl for eating, as well as a small beaker of the type that holds oil or spices. All of these vessels were ceramic, some ritually broken and but with most or all of the fragments buried together in the pit. Further, most of the pots seem to be locally made rather than imported. They were offering to the gods their own special creations.

"We should be able to restore these vases and have quite a splendid array of Etruscan pottery dating from a single moment and a particular place in their history," de Grummond said.

Also of great interest to de Grummond was the discovery of some 10 iron nails deposited in the pit, all in an excellent state of preservation.

"These reflect what we know from ancient texts in Latin that note that the Etruscans treated nails as sacred, and regarded them as symbolizing inexorable fate," she said. "They had a ritual practice in regard to their deity Nurtia in which they would hammer a nail into the wall of the temple each year as a tribute to the goddess. We cannot yet be sure about the cultic significance of the nails of Cetamura, but they may well relate to the passage of time and thus to the sacred calendar of the Etruscans."

One of de Grummond's students also unearthed an Etruscan inscription on a shard of pottery that contained the name of a little-known Etruscan god, Lurs.
.

"Almost nothing is known about Lurs, but we may have at Cetamura some very rare evidence about his worship," she said.

De Grummond is a leading scholar on the religious practices of the Etruscans, a people whose culture profoundly influenced the ancient Romans and Greeks. "The Religion of the Etruscans," a book written and edited by de Grummond and Erika Simon, another expert in classical archaeology who served as the Langford Family Eminent Scholar in Classics at FSU in 1999, was published last spring. De Grummond soon will release another book, "Etruscan Myth, Sacred History and Legend."

De Grummond said she hopes to continue excavating the Cetamura sacred area, and building on nearly a quarter-century of knowledge that she has gathered there.

"It is a bit eerie to have excavated something so central to my own lifelong interest in the myth, religion and rituals of the Etruscans," she said. "Without a doubt, this is one of the most exciting of the discoveries I have experienced."

SOURCE: EUREKAALERT.

Men are the same as women, just inside out !

[4getmenot]

Now i know why they say "it's just the tip of the iceburg"lol..



k

[neilep]

Cassini's radar mapper finds possible lakes on Titan
CASSINI PHOTO RELEASE





Want a bigger piccy ?..then click HERE

The Cassini spacecraft, using its radar system, has discovered very strong evidence for hydrocarbon lakes on Titan. Dark patches, which resemble terrestrial lakes, seem to be sprinkled all over the high latitudes surrounding Titan's north pole.

Scientists have speculated that liquid methane or ethane might form lakes on Titan, particularly near the somewhat colder polar regions. In the images, a variety of dark patches, some with channels leading in or out of them, appear. The channels have a shape that strongly implies they were carved by liquid. Some of the dark patches and connecting channels are completely black, that is, they reflect back essentially no radar signal, and hence must be extremely smooth. In some cases rims can be seen around the dark patches, suggesting deposits that might form as liquid evaporates. The abundant methane in Titan's atmosphere is stable as a liquid under Titan conditions, as is its abundant chemical product, ethane, but liquid water is not.

For all these reasons, scientists interpret the dark areas as lakes of liquid methane or ethane, making Titan the only body in the solar system besides Earth known to possess lakes. Because such lakes may wax and wane over time, and winds may alter the roughness of their surfaces. Repeat coverage of these areas should test whether indeed these are bodies of liquid.

These two radar images were acquired by the Cassini radar instrument in synthetic aperture mode on July 21, 2006. The top image centered near 80 degrees north, 92 degrees west measures about 420 kilometers by 150 kilometers (260 miles by 93 miles). The lower image centered near 78 degrees north, 18 degrees west measures about 475 kilometers by 150 kilometers (295 miles by 93 miles). Smallest details in this image are about 500 meters (1,640 feet) across.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.


SOURCE: SPACEFLIGHTNOW.COM

Men are the same as women, just inside out !

[neilep]

Going out with a bang
Lunar orbiter to impact
BY STEPHEN CLARK
SPACEFLIGHT NOW


A pioneering space probe has set a course for a dramatic end to its three-year mission in September, when it will collide with the Moon in a spectacular send-off for scientists to learn new information about the lunar surface.


This artist's impression shows the trajectory of the SMART-1 spacecraft in the final phase of its mission. Credits: ESA

BIG PICCY right here

 
Going out with a bang
Lunar orbiter to impact
BY STEPHEN CLARK
SPACEFLIGHT NOW
Posted: July 24, 2006

A pioneering space probe has set a course for a dramatic end to its three-year mission in September, when it will collide with the Moon in a spectacular send-off for scientists to learn new information about the lunar surface.


This artist's impression shows the trajectory of the SMART-1 spacecraft in the final phase of its mission. Credits: ESA
Download larger image version here
 
 
The innovative SMART-1 technology demonstrator is about to wrap up a highly successful mission testing a range of new spacecraft concepts and systems for potential use in the future. The Swedish-built craft also conducted a broad science program using an array of instruments.

The end will come with a fiery crash into the Moon's nearside at about 0541 GMT (1:41 a.m. EDT) on September 3, according to the best data now available. This time is only certain within seven hours.

The exact timing of the impact will slightly change as the probe's orbit evolves in several upcoming trim maneuvers designed to fine-tune the craft's approach. Five such burns are planned for July 27, July 28, August 25, and on the final two days before SMART-1 hits the surface.

Scientists' "best guess" on the impact site puts it in the Moon's mid-southern latitudes in a region known as the Lake of Excellence. The location is believed to be of mostly volcanic origin and areas of highlands and hills are also nearby. The area is also known as Lacus Excellentiae in Latin.

At the time of impact, the Lake of Excellence will be shrouded in darkness - only slightly illuminated by light from the Earth in a phenomenon called "earthshine." The boundary between bright sunshine and nighttime on the Moon will be located not far away, possibly allowing material blown above the surface to reach altitudes high enough to be lit by sunlight.

Ground controllers in Germany had to command a two-week series of thruster firings to raise the low point of SMART-1's trek around the Moon to push back the inevitable crash from about August 17 to the current date of September 3. The plan also brought the forecasted impact site into the direct view of scientists on the ground. If left undisturbed, the 630-pound probe would have smacked into the far side of the Moon facing away from Earth.

The set of orbit-raising maneuvers began June 19 and ended on July 2 - about five days ahead of schedule.

Astronomers at observatories across the globe plan to try to see the plume of debris ejected high above the lunar surface as SMART-1 drives into the Moon. Organized groups at the European Southern Observatory in Chile, Kitt Peak in Arizona, telescopes in Hawaii, and other locations will attempt to spot the impact and its aftermath

The most favorable position for observing an on-time impact will be in North and South America and Hawaii. There, the quarter Moon will be high in the sky for prime viewing.

Larger telescopes could detect a flash at the moment of impact due to vaporized hydrazine fuel. A few minutes later, dust and rocks thrown high above the Moon might be seen. If the debris reaches an altitude of over 12 miles, it could be lit by sunlight. If so, amateur astronomers with smaller backyard telescopes could see the dust cloud backdropped by the darker lunar surface.

"We are calling upon astronomical observatories and amateurs worldwide to participate in a coordinated observation effort with SMART-1, including the final orbits until impact," said European Space Agency SMART-1 project scientist Bernard Foing.

Instruments to be operating during SMART-1's final hours include an infrared spectrometer, an X-ray spectrometer, and a tiny camera to take pictures of the Moon as the spacecraft passes near the surface.

The material propelled into sunlight will be closely analyzed to determine details such as its mineral composition and physical properties. Some of the debris could be excavated from underground during SMART-1's crash, so scientists are especially interested in learning about the sub-surface of the Moon.

During SMART-1's final orbits, the spacecraft should be speeding just a few miles above the lunar surface. Accurate predictions of the expected impact time and location are hard to produce because of unknown variations in topography along the probe's trajectory over the Moon. Officials say an unexpected mountain or cliff could cause the craft to crash earlier than anticipated.

By early September, SMART-1 will complete one orbit of the Moon about every five hours. With each orbit's closest approach to the surface, the probe will slowly descend further.

Two low passes before the most likely impact time are also being closely watched in case SMART-1 hits the Moon early. If the spacecraft strikes the Moon at 0037 GMT, observers in South America and the Canary Islands will garner the best view of the event. One orbit earlier - at 1933 GMT on September 2 - astronomers based in Europe and Africa will have the best chance to view the crash.

At first contact, engineers believe SMART-1 will gently glide down at a vertical speed of just under 45 miles per hour, assuming the impact is on a relatively flat surface. However, the craft will be traveling at a horizontal clip of well over 4,000 miles per hour. The low-angle impact could carve a crater up to three feet deep and a couple dozen feet wide.

The testbed carries an efficient ion engine that is fueled by a relatively small amount of xenon fuel and electricity. Strides have also been made in autonomous navigation through ground software that can remotely track the craft's position and velocity through images of stars taken by an on-board camera. Several communications tests through lasers and higher radio frequencies were also carried out.

On the scientific front, SMART-1 has captured and returned up to 1,000 images per week during the past 15 months. Its miniature visible camera is fitted with several color filters, so scientists were also able to take several black-and-white pictures of the same area and artificially create a color image.

The spacecraft's instruments have also been working on studies of lunar composition and the search for ice hidden in the bottoms of polar craters. SMART-1 has also collected evidence on the Moon's evolution and origin. Extensive mapping operations have also been a priority for planning in advance of future lunar missions.

SMART-1 has been circling the Moon since November 2004, almost 14 months after launching aboard an Ariane 5 rocket in September 2003. The probe took a circuitous route to the Moon, completing 332 orbits around Earth while using its electric propulsion system to gently nudge it higher before finally slipping into lunar orbit.

While transitioning to a stable science orbit a few months later, SMART-1 was quickly granted a mission extension in February 2005 that allowed the mission to continue operations through August of this year.

The mission is the first member of the European Space Agency's Small Missions for Advanced Research in Technology program. SMART missions are designed to test new technologies before employing them on more expensive projects.
 
SOURCE: SPACEFLIGHTNOW.COM

Men are the same as women, just inside out !

[neilep]

New view of quasar emerges
HARVARD-SMITHSONIAN CENTER FOR ASTROPHYSICS NEWS RELEASE


In the distant, young universe, quasars shine with a brilliance unmatched by anything in the local cosmos. Although they appear starlike in optical telescopes, quasars are actually the bright centers of galaxies located billions of light-years from Earth.



This artist's conceptual drawing shows the core of a quasar known as
 Q0957+561. Observations indicate that the quasar contains a 4-billion solar-mass object that astronomers have dubbed a
magnetospheric eternally collapsing object, or MECO for short.
Credit: Christine Pulliam (CfA)

The seething core of a quasar currently is pictured as containing a disk of hot gas spiraling into a supermassive black hole. Some of that gas is forcefully ejected outward in two opposing jets at nearly the speed of light. Theorists struggle to understand the physics of the accretion disk and jets, while observers struggle to peer into the quasar's heart. The central "engine" powering the jets is difficult to study telescopically because the region is so compact and Earth observers are so far away.

Astronomer Rudy Schild of the Harvard-Smithsonian Center for Astrophysics (CfA) and his colleagues studied the quasar known as Q0957+561, located about 9 billion light-years from Earth in the direction of the constellation Ursa Major, near the Big Dipper. This quasar holds a central compact object containing as much mass as 3-4 billion Suns. Most would consider that object to be a "black hole," but Schild's research suggests otherwise.

"We don't call this object a black hole because we have found evidence that it contains an internally anchored magnetic field that penetrates right through the surface of the collapsed central object, and that interacts with the quasar environment," commented Schild.

The researchers chose Q0957+561 for its association with a natural cosmic lens. The gravity of a nearby galaxy bends space, forming two images of the distant quasar and magnifying its light. Stars and planets within the nearby galaxy also affect the quasar's light, causing small fluctuations in brightness (in a process called "microlensing") when they drift into the line of sight between Earth and the quasar.

Schild monitored the quasar's brightness for 20 years, and led an international consortium of observers operating 14 telescopes to keep the object under steady around-the-clock watch at critical times.

"With microlensing, we can discern more detail from this so-called 'black hole' two-thirds of the way to the edge of the visible universe than we can from the black hole at the center of the Milky Way," said Schild.

Through careful analysis, the team teased out details about the quasar's core. For example, their calculations pinpointed the location where the jets form.

"How and where do these jets form? Even after 60 years of radio observations, we had no answer. Now the evidence is in, and we know," said Schild.

Schild and his colleagues found that the jets appear to emerge from two regions 1,000 astronomical units in size (about 25 times larger than the Pluto-Sun distance) located 8,000 astronomical units directly above the poles of the central compact object. (An astronomical unit is defined as the average distance from the Earth to the Sun, or 93 million miles.) However, that location would be expected only if the jets were powered by reconnecting magnetic field lines that were anchored to the rotating supermassive compact object within the quasar. By interacting with a surrounding accretion disk, such spinning magnetic field lines spool up, winding tighter and tighter until they explosively unite, reconnect and break, releasing huge amounts of energy that power the jets.

"This quasar appears to be dynamically dominated by a magnetic field internally anchored to its central, rotating supermassive compact object," stated Schild.

Further evidence for the importance of the quasar's internally anchored magnetic field is found in surrounding structures. For example, the inner region closest to the quasar appears to have been swept clean of material. The inner edge of the accretion disk, located about 2,000 astronomical units from the central compact object, is heated to incandescence and glows brightly. Both effects are the physical signatures of a swirling, internal magnetic field being pulled around by the rotation of the central compact object - a phenomenon dubbed the "magnetic propeller effect."

Observations also suggest the presence of a broad cone-shaped outflow from the accretion disk. Where lit by the central quasar, it shines in a ring-like outline known as the Elvis structure after Schild's CfA colleague, Martin Elvis, who theorized its existence. The surprisingly large angular opening of the outflow that is observed is best explained by the influence of an intrinsic magnetic field contained within the central compact object in this quasar.

In light of these observations, Schild and his colleagues, Darryl Leiter (Marwood Astrophysics Research Center) and Stanley Robertson (Southwestern Oklahoma State University), have proposed a controversial theory that the magnetic field is intrinsic to the quasar's central, supermassive compact object, rather than only being part of the accretion disk as thought by most researchers. If confirmed, this theory would lead to a revolutionary new picture of quasar structure.

"Our finding challenges the accepted view of black holes," said Leiter. "We've even proposed a new name for them - Magnetospheric Eternally Collapsing Objects, or MECOs," a variant of the name first coined by Indian astrophysicist Abhas Mitra in 1998. "Astrophysicists of 50 years ago did not have access to the modern understanding of quantum electrodynamics that is behind our new solutions to Einstein's original equations of relativity."

This research suggests that, in addition to its mass and spin, the quasar's central compact object may have physical properties more like a highly redshifted, spinning magnetic dipole than like a black hole. For that reason, most approaching matter does not disappear forever, but instead feels the motor-like rotating magnetic field and gets spun back out. According to this theory, a MECO does not have an event horizon, so any matter that is able to get by the magnetic propeller is gradually slowed down and stopped at the MECO's highly redshifted surface, with just a weak signal connecting the radiation from that matter to a distant observer. That signal is very hard to observe and has not been detected from Q0957+561.

This research was published in the July 2006 issue of the Astronomical Journal.



SOURCE:SPACEFLIGHTNOW.COM




Men are the same as women, just inside out !

[neilep]

 
Planet-forming disks might put the brakes on stars
JET PROPULSION LABORATORY NEWS RELEASE


Astronomers using NASA's Spitzer Space Telescope have found evidence that dusty disks of planet-forming material tug on and slow down the young, whirling stars they surround.
 


This artist's concept demonstrates how a dusty planet-forming disk
can slow down a whirling young star, essentially saving the star
from spinning itself to death. Credit: NASA/JPL-Caltech

Young stars are full of energy, spinning around like tops in half a day or less. They would spin even faster, but something puts on the brakes. While scientists had theorized that planet-forming disks might be at least part of the answer, demonstrating this had been hard to do until now.

"We knew that something must be keeping the stars' speed in check," said Dr. Luisa Rebull of NASA's Spitzer Science Center, Pasadena, Calif. "Disks were the most logical answer, but we had to wait for Spitzer to see the disks."

Rebull, who has been working on the problem for nearly a decade, is lead author of a new paper in the July 20 issue of the Astrophysical Journal. The findings are part of a quest to understand the complex relationship between young stars and their burgeoning planetary systems.

Stars begin life as collapsing balls of gas that spin faster and faster as they shrink, like twirling ice skaters pulling in their arms. As the stars whip around, excess gas and dust flatten into surrounding pancake-like disks. The dust and gas in the disks are believed to eventually clump together to form planets.

Developing stars spin so fast that, left unchecked, they would never fully contract and become stars. Prior to the new study, astronomers had theorized that disks might be slowing the super speedy stars by yanking on their magnetic fields. When a star's fields pass through a disk, they are thought to get bogged down like a spoon in molasses. This locks a star's rotation to the slower-turning disk, so the shrinking star can't spin faster.

To prove this principle, Rebull and her team turned to Spitzer for help. Launched in August of 2003, the infrared observatory is an expert at finding the swirling disks around stars, because dust in the disks is heated by starlight and glows at infrared wavelengths.

The team used Spitzer to observe nearly 500 young stars in the Orion nebula. They divided the stars into slow spinners and fast spinners, and determined that the slow spinners are five times more likely to have disks than the fast ones.

"We can now say that disks play some kind of role in slowing down stars in at least one region, but there could be a host of other factors operating in tandem. And stars might behave differently in different environments," Rebull said.

Other factors that contribute to a star's winding down over longer periods of time include stellar winds and possibly full-grown planets.

If planet-forming disks slow down stars, does that mean stars with planets spin more slowly than stars without planets? Not necessarily, according to Rebull, who said slowly spinning stars might simply take more time than other stars to clear their disks and develop planets. Such late-blooming stars would, in effect, give their disks more time to put on the brakes and slow them down.

Ultimately, the question of how a star's rotation rate is related to its ability to support planets will fall to planet hunters. So far, all known planets in the universe circle stars that turn around lazily. Our sun is considered a slowpoke, currently plodding along at a rate of one revolution every 28 days. And, due to limits in technology, planet hunters have not been able to find any extrasolar planets around zippy stars.

"We'll have to use different tools for detecting planets around rapidly spinning stars, such as next-generation ground and space telescopes," said Dr. Steve Strom, an astronomer at the National Optical Astronomy Observatory, Tucson, Ariz.

Other members of Rebull's team include Drs. John Stauffer of the Spitzer Science Center; S. Thomas Megeath at the University of Toledo, Ohio; and Joseph Hora and Lee Hartmann of the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass. Hartmann is also affiliated with the University of Michigan, Ann Arbor.



SOURCE: SPACEFLIGHTNOW.COM
 


Men are the same as women, just inside out !

[neilep]

New definition would add 3 "planets" to Solar System
ASTRONOMICAL UNION NEWS RELEASE
Posted: August 16, 2006

The world's astronomers, under the auspices of the International Astronomical Union (IAU), have concluded two years of work defining the difference between "planets" and the smaller "solar system bodies" such as comets and asteroids. If the definition is approved by the astronomers gathered 14-25 August 2006 at the IAU General Assembly in Prague, our Solar System will include 12 planets, with more to come: eight classical planets that dominate the system, three planets in a new and growing category of "plutons" - Pluto-like objects - and Ceres. Pluto remains a planet and is the prototype for the new category of "plutons."




If the definition is approved by the astronomers gathered at the IAU
 General Assembly in Prague, our Solar System will consist of 12
planets: Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn,
Uranus, Neptune, Pluto, Charon and 2003 UB313. The three new
proposed planets are Ceres, Charon (Pluto's companion) and 2003
UB313. Credit: The International Astronomical Union/Martin Kornmesser



With the advent of powerful new telescopes on the ground and in space, planetary astronomy has gone though an exciting development over the past decade. For thousands of years very little was known about the planets other than they were objects that moved in the sky with respect to the background of fixed stars. In fact the word "planet" comes from the Greek word for "wanderer". But today hosts of newly discovered large objects in the outer regions of our Solar System present a challenge to our historically based definition of a "planet".

At first glance one should think that it is easy to define what a planet is - a large and round body. On second thought difficulties arise, as one could ask "where is the lower limit?" - how large, and how round should an asteroid be before it becomes a planet - as well as "where is the upper limit?" - how large can a planet be before it becomes a brown dwarf or a star?

IAU President Ron Ekers explains the rational behind a planet definition: "Modern science provides much more knowledge than the simple fact that objects orbiting the Sun appear to move with respect to the background of fixed stars. For example, recent new discoveries have been made of objects in the outer regions of our Solar System that have sizes comparable to and larger than Pluto. These discoveries have rightfully called into question whether or not they should be considered as new ‘planets.' "

The International Astronomical Union has been the arbiter of planetary and satellite nomenclature since its inception in 1919. The world's astronomers, under the auspices of the IAU, have had official deliberations on a new definition for the word "planet" for nearly two years. IAU's top, the so-called Executive Committee, led by Ekers, formed a Planet Definition Committee (PDC) comprised by seven persons who were astronomers, writers, and historians with broad international representation. This group of seven convened in Paris in late June and early July 2006. They culminated the two year process by reaching a unanimous consensus for a proposed new definition of the word "planet


The three new planets. Credit: The International Astronomical Union/Martin Kornmesser

Owen Gingerich, the Chair of the Planet Definition Committee says: "In July we had vigorous discussions of both the scientific and the cultural/historical issues, and on the second morning several members admitted that they had not slept well, worrying that we would not be able to reach a consensus. But by the end of a long day, the miracle had happened: we had reached a unanimous agreement."

The part of "IAU Resolution 5 for GA-XXVI" that describes the planet definition, states "A planet is a celestial body that (a) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (b) is in orbit around a star, and is neither a star nor a satellite of a planet." Member of the Planet Definition Committee, Richard Binzel says: "Our goal was to find a scientific basis for a new definition of planet and we chose gravity as the determining factor. Nature decides whether or not an object is a planet."

According to the new draft definition, two conditions must be satisfied for an object to be called a "planet." First, the object must be in orbit around a star, while not being itself a star. Second, the object must be large enough (or more technically correct, massive enough) for its own gravity to pull it into a nearly spherical shape. The shape of objects with mass above 5 x 1020 kg and diameter greater than 800 km would normally be determined by self-gravity, but all borderline cases would have to be established by observation.

If the proposed Resolution is passed, the 12 planets in our Solar System will be Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Charon and 2003 UB313. The name 2003 UB313 is provisional, as a "real" name has not yet been assigned to this object. A decision and announcement of a new name are likely not to be made during the IAU General Assembly in Prague, but at a later time. The naming procedures depend on the outcome of the Resolution vote. There will most likely be more planets announced by the IAU in the future. Currently a dozen "candidate planets" are listed on IAU's "watchlist" which keeps changing as new objects are found and the physics of the existing candidates becomes better known.


There will most likely be more planets announced by the IAU in the
future. Currently a dozen "candidate planets" are listed on
IAU's "watchlist" which keeps changing as new objects are found and
the physics of the existing candidates becomes better known. A
number of these planet candidates are shown here. Credit: The
International Astronomical Union/Martin Kornmesser

The IAU draft Resolution also defines a new category of planet for official use: "pluton". Plutons are distinguished from classical planets in that they reside in orbits around the Sun that take longer than 200 years to complete (i.e. they orbit beyond Neptune). Plutons typically have orbits that are highly tilted with respect to the classical planets (technically referred to as a large orbital inclination). Plutons also typically have orbits that are far from being perfectly circular (technically referred to as having a large orbital eccentricity). All of these distinguishing characteristics for plutons are scientifically interesting in that they suggest a different origin from the classical planets.

The draft "Planet Definition" Resolution will be discussed and refined during the General Assembly and then it (plus four other Resolutions) will be presented for voting at the 2nd session of the GA 24 August between 14:00 and 17:30 CEST.

The IAU is the international astronomical organisation that brings together distinguished astronomers from all nations of the world. IAU's mission is to promote and safeguard the science of astronomy in all its aspects through international cooperation. Founded in 1919, the IAU is the world's largest professional body for astronomers. The IAU General Assembly is held every three years and is one of the largest and most diverse meetings in the astronomical community's calendar.

SOURCE: SPACEFLIGHTNOW.COM  Hmmm...sticky toffee sauce is also nice ! []








Men are the same as women, just inside out !

[neilep]

Digging up troves of possible solar systems in Orion
NASA/JPL NEWS RELEASE
Posted: August 14, 2006

Astronomers have long scrutinized the vast and layered clouds of the Orion nebula, an industrious star-making factory visible to the naked eye in the sword of the famous hunter constellation. Yet, Orion is still full of secrets.


This infrared image from Spitzer shows the Orion nebula, our closest
massive star-making factory, 1,450 light-years from Earth. The
nebula is close enough to appear to the naked eye as a fuzzy star in
the sword of the popular hunter constellation. The nebula itself is
located on the lower half of the image, surrounded by a ring of
dust. It formed in a cold cloud of gas and dust and contains about 1,000 young stars. These stars illuminate the cloud, creating the
beautiful nebulosity, or swirls of material, seen here in infrared. Credit: NASA/JPL-Caltech/ T. Megeath (University of Toledo)
Download larger image version here

A new image from NASA's Spitzer Space Telescope probes deep into the clouds of dust that permeate the nebula and its surrounding regions. The striking false-color picture shows pinkish swirls of dust speckled with stars, some of which are orbited by disks of planet-forming dust.

Spitzer, with its powerful infrared vision, was able to unearth nearly 2,300 such planet-forming disks in the Orion cloud complex, a collection of turbulent star-forming clouds that includes the well-known Orion nebula.

The disks - made of gas and dust that whirl around young suns - are too small and distant to be seen by visible-light telescopes; however, the infrared glow of their warm dust is easily spotted by Spitzer's infrared detectors. Each disk has the potential to form planets and its own solar system.

"This is the most complete census of young stars with disks in the Orion cloud complex," said Dr. Thomas Megeath of the University of Toledo, Ohio, who led the research. "Basically, we have a census of potential solar systems, and we want to know how many are born in the cities, how many in small towns, and how many out in the countryside."

A look at Orion's demographics reveals that the potential solar systems populate a variety of environments. Megeath and his colleagues found that about 60 percent of the disk-sporting stars in the Orion cloud complex inhabit its bustling "cities," or clusters, containing hundreds of young stars. About 15 percent reside in small outer communities, and a surprising 25 percent prefer to go it alone, living in isolation.

Prior to the Spitzer observations, scientists thought that up to 90 percent of young stars, both with and without disks, dwelled in cities like those of Orion.

"The Orion image shows that many stars also appear to form in isolation or in groups of just a few stars," said team member Dr. John Stauffer of NASA's Spitzer Science Center at the California Institute of Technology in Pasadena. "These new data may help us to determine the type of environment in which our sun formed."

Astronomers do not know whether our middle-aged sun grew up in the stellar equivalent of the city or countryside, though most favor a large city scenario. Newborn stars like the ones in Orion tend to drift away from their siblings over time, so it is hard to trace an adult star's origins.

Megeath and his colleagues estimate that about 60 to 70 percent of the stars in the Orion cloud complex have disks. "It is an interesting question why this number isn't 100 percent. Eventually, we may be able to understand why some stars don't have disks," said Megeath.

Spitzer's infrared vision also dug up 200 stellar embryos in the Orion cloud complex, most of which had never been seen before. Stellar embryos are still too young to have developed disks.

The Orion cloud complex is about 1,450 light-years from Earth and spans about 240 light-years of space. Spitzer's wide field of view allowed it to survey most of the complex, an area of the sky equivalent to 28 full moons. The featured image shows a slice of this survey, the equivalent of four full moons-worth of sky, and includes the Orion nebula itself.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center. Caltech manages JPL for NASA. Spitzer's infrared array camera, which made the observations, was built by NASA's Goddard Space Flight Center, Greenbelt, Md. The instrument's principal investigator is Dr. Giovanni Fazio of the Harvard-Smithsonian Center for Astrophysics.


SOURCE: SPACEFLIGHTNOW.COM

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Men are the same as women, just inside out !

[neilep]

Large and small stars in harmonious coexistence
HUBBLE EUROPEAN SPACE AGENCY INFORMATION CENTRE
Posted: August 14, 2006



Credit: NASA, ESA and D. A. Gouliermis (MPIA)
Download larger image version here (careful if you have dial up...it's BIG !!


The latest photo from the Hubble Space Telescope, presented at the 2006 General Assembly of the International Astronomical Union in Prague this week, shows a star forming region in the Large Magellanic Cloud (LMC). This sharp image reveals a large number of low-mass infant stars coexisting with young massive stars.

This is a Hubble Space Telescope image of one of the hundreds of star- forming stellar systems, called stellar associations, located 180,000 light-years away in the Large Magellanic Cloud (LMC). The LMC is the second closest known satellite galaxy of our Milky Way, orbiting it roughly every 1.5 billion years.

Earlier ground-based observations of such systems had only allowed astronomers to study the bright blue giant stars in these systems, and not the low-mass stars.

This new, most detailed view to date of the star-forming association LH 95 was taken with Hubble's Advanced Camera for Surveys and provides a extraordinarily rich sample of newly formed low-mass stars, allowing a more accurate calculation of their ages and masses. An international team of astronomers, led by Dimitrios Gouliermis of the Max-Planck Institute for Astronomy (MPIA) in Heidelberg, is currently studying the Hubble data.

According to Dr. Gouliermis "Hubble's sharp vision has over the years dramatically changed the picture that we had for stellar associations in the Magellanic Clouds". The LMC is a galaxy with relatively small amounts of elements heavier than hydrogen, giving astronomers an insight into star-formation in environments different from our Milky Way.




These images reveal details of the LH 95 region. From
top to bottom and left to right they show a dense part of the
parental molecular cloud, a compact cluster of faint infant stars,
the main part of LH 95, where massive and low-mass stars coexist
close to a dusty lane, and one of the remarkable background
galaxies. Credit: NASA, ESA

Download larger image version here




 
Once massive stars - those with at least 3 times the mass of the Sun - have formed, they generate strong stellar winds and high levels of ultraviolet radiation that ionize the surrounding interstellar gas. The result is a nebula of glowing hydrogen that will expand out into the molecular cloud that originally collapsed to form these stars. The blue haze seen throughout the image around LH 95 is actually part of this bright nebula, known as DEM L 252.

Some dense parts of this star-forming region have not been completely eroded by the stellar winds and can still be seen as dark dusty filaments in the picture. Such dust lanes absorb parts of the blue light from the stars behind them, making them appear redder. Other parts of the molecular cloud have already contracted to turn into glowing groups of infant stars, the fainter of which have a high tendency to cluster.

The new Hubble view of LH 95 shows that there are at least two small compact clusters associated with such groups, one to the right, above the centre of the picture and one to the far left. These stellar nurseries host hundreds of newly discovered infant low- mass stars. Such stars have also been found by Hubble in the main part of LH 95 amongst its massive bright stellar members.

This deep image also reveals a variety of distant galaxies, seen as reddish spirals and elliptical galaxies decorating the background of LH 95.

The Large and Small Magellanic Clouds can be seen by the naked eye in the southern hemisphere.

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.


Source: SPACEFLIGHTNOW.COM

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Men are the same as women, just inside out !

[neilep]

Surprising observations shake up galactic theories
UNIVERSITY OF COLORADO-BOULDER NEWS RELEASE
Posted: August 14, 2006

A heavy form of hydrogen created just moments after the Big Bang has been found to exist in larger quantities than expected in the Milky Way, a finding that could radically alter theories about star and galaxy formation, says a new international study led by the University of Colorado at Boulder.




This is a false-color image of the star AE Aurigae (bright source of
light slightly off center of image) embedded in a region of space
containing smoke-like filaments of carbon-rich dust grains, a common
phenomenon. Such dust might be hiding deuterium, an isotope of
hydrogen, and stymieing astronomers' efforts to study star and
galaxy formation. The FUSE satellite has surveyed the local
deuterium concentration in the galaxy and found far more than
expected. Because deuterium is a tracer of star and galaxy
evolution, this discovery could radically alter theories about how
stars and galaxy form. Credit: T.A. Rector and B.A. Wolpa, NOAO,
AURA, and NSF
Download larger image versionhere

CU-Boulder astrophysicist Jeffrey Linsky said new data gathered by NASA's Far Ultraviolet Spectroscopic Explorer, or FUSE, satellite, shows why deuterium appears to be distributed unevenly in the Milky Way Galaxy. It apparently has been binding to interstellar dust grains, changing from an easily detectable gaseous form to an unobservable solid form, said Linsky, a fellow of JILA, a joint institute of CU-Boulder and the National Institute of Standards and Technology.

The FUSE deuterium study, six years in the making, solves a 35-year- old mystery concerning the distribution of deuterium in the Milky Way while posing new questions about how stars and galaxies are made, according to the research team. A paper on the subject by a team of international researchers led by Linsky is being published in the Aug. 20 issue of The Astrophysical Journal.

"Since the 1970s, we have been unable to explain why deuterium levels vary all over the place," said Linsky. "The answer we found is as unsettling as it is exciting."

Since deuterium -- a hydrogen isotope containing a proton and a neutron -- is believed burned and lost forever during star formation, scientists think the amount of deuterium present in the universe is "pure" and serves as a tracer for star creation and galaxy building over billions of years, said Linsky. While primordial deuterium in the distant, early universe has been measured at concentrations of about 27 parts per million parts hydrogen atoms, measurements by FUSE and NASA's Copernicus satellite have shown a "patchy" distribution of the element in the Milky Way galaxy, often at far lower levels.

In 2003, Princeton University's Bruce Draine, a co-author on the new study, developed a model showing that deuterium, when compared to hydrogen, might preferentially bind to interstellar dust grains. The observations by FUSE -- which can detect the telltale spectral fingerprints of deuterium in the ultraviolet energy range -- strongly support the theory, according to The Astrophysical Journal paper authors.

"Where there are high concentrations of interstellar dust in the galaxy, we see lower concentrations of deuterium gas with FUSE," said Linsky. "And where there is less interstellar dust, we are measuring higher levels of deuterium gas."

In relatively undisturbed areas of the universe -- like regions around Earth's sun, for example -- deuterium atoms systematically "leave" the gas phase and replace normal hydrogen atoms in dust grains, said Linsky. When a pocket of the universe is disturbed by events like a supernova shock wave or violent activity triggered by nearby hot stars, the dust grains are vaporized, releasing deuterium atoms back into a gas, which has been measured by FUSE, the researchers said.

Scientists assumed from astrophysical theories that at least one- third of the primordial deuterium present in the Milky Way was destroyed over time as it cycled through the stars, said Linsky. But according to the new FUSE findings, the present-day deuterium abundance is less than 15 percent below the primordial values.

"This implies that either significantly less material has been converted to helium and heavier elements in stars or that much more primordial gas has rained down onto the galaxy over its lifetime than had been thought," said Linsky. "In either case, our models of the chemical evolution of the Milky Way will have to be revised significantly to explain this important new result."

Launched in 1999, FUSE is a NASA Explorer mission developed in cooperation with the French and Canadian Space Agencies and by Johns Hopkins University, CU-Boulder and the University of California, Berkeley. CU-Boulder's Center for Astrophysics and Space Astronomy designed and built the mission's $9 million spectrograph, which collects and funnels UV light from the satellite's four telescopes.

The paper was co-authored by scientists from Princeton, Johns Hopkins and Northwestern universities, the Space Telescope Science Institute, CU-Boulder, the University of Wisconsin-Madison, the University of Texas-Austin, NASA-Goddard, the Laboratoire d'Astrophysique in Marseille, France, and the Observatoire de Paris- Meudon in Meudon, France.

Other CU-Boulder co-authors include JILA's Brian Wood, CASA's Michael Shull and CASA doctoral graduate Seth Redfield.

SOURCE: SPACEFLIGHTNOW.COM

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Men are the same as women, just inside out !