Hello.
I want to put this post to talk about latest news around astronomy, Its a new astronomical news page......
I'll appreciate if u help me with this post........
Thank u All
Hello.
I want to put this post to talk about latest news around astronomy, Its a new astronomical news page......
I'll appreciate if u help me with this post........
Thank u All
ویرایش توسط planetstruck : 04-11-2011 در ساعت 09:36 AM دلیل: Adding words,Correcting Grammar points
The magnetic field strength in the core is 50 times stronger than that at Earth’s surface.
By University of California, Berkeley — Published: December 20, 2010
A cross-section of Earth's interior shows the outer crust, the hot gooey mantle, the liquid outer core, and the solid, frozen inner core (gray). Graphic: Calvin J. Hamilton
A University of California, Berkeley, geophysicist has made the first-ever measurement of the strength of the magnetic field inside Earth's core, 1,800 miles (2,900 kilometers) underground.
The magnetic field strength is 25 Gauss, or 50 times stronger than the magnetic field at the surface that makes compass needles align north-south. Although geophysicists predict this number is in the middle of the range, it puts constraints on the identity of the heat sources in the core that keep the internal dynamo running to maintain this magnetic field.
"This is the first really good number we've had based on observations, not inference," said Bruce A. Buffett from University of California, Berkeley. "The result is not controversial, but it does rule out a very weak magnetic field and argues against a very strong field."
A strong magnetic field inside the outer core means there is a lot of convection and a lot of heat being produced, which scientists would need to account for, Buffett said. The presumed sources of energy are the residual heat from 4 billion years ago when the planet was hot and molten, the release of gravitational energy as heavy elements sink to the bottom of the liquid core, and the radioactive decay of long-lived elements such as potassium, uranium, and thorium.
A weak field — 5 Gauss, for example — would imply that little heat is being supplied by radioactive decay, while a strong field, on the order of 100 Gauss, would imply a large contribution from radioactive decay.
"A measurement of the magnetic field tells us what the energy requirements are and what the sources of heat are," Buffett said.
About 60 percent of the power generated inside Earth likely comes from the exclusion of light elements from the solid inner core as it freezes and grows, he said. This constantly builds up crud in the outer core.
The Earth's magnetic field is produced in the outer two-thirds of the planet's iron/nickel core. This outer core, about 1,400 miles (2,300 km) thick, is liquid, while the inner core is a frozen iron and nickel wrecking ball with a radius of about 800 miles (1,300 km) — roughly the size of the Moon. A hot, gooey mantle and a rigid surface crust surround the core.
The cooling Earth originally captured its magnetic field from the planetary disk in which the solar system formed. That field would have disappeared within 10,000 years if not for the planet's internal dynamo, which regenerates the field thanks to heat produced inside the planet. The heat makes the liquid outer core boil, or "convect," and as the conducting metals rise and then sink through the existing magnetic field, they create electrical currents that maintain the magnetic field. This roiling dynamo produces a slowly shifting magnetic field at the surface.
"You get changes in the surface magnetic field that look a lot like gyres and flows in the oceans and the atmosphere, but these are being driven by fluid flow in the outer core," Buffett said.
Buffett is a theoretician who uses observations to improve computer models of Earth's internal dynamo. Now at work on a second-generation model, he admits that a lack of information about conditions in the Earth's interior has been a big hindrance to making accurate models.
He realized, however, that the tug of the Moon on the tilt of Earth's spin axis could provide information about the magnetic field inside. This tug would make the inner core precess — that is, make the spin axis slowly rotate in the opposite direction — which would produce magnetic changes in the outer core that damp the precession. Radio observations of distant quasars — extremely bright, active galaxies — provide precise measurements of the changes in Earth's rotation axis needed to calculate this damping.
"The Moon is continually forcing the rotation axis of the core to precess, and we're looking at the response of the fluid outer core to the precession of the inner core," he said.
By calculating the effect of the Moon on the spinning inner core, Buffett discovered that the precession makes the slightly out-of-round inner core generate shear waves in the liquid outer core. These waves of molten iron and nickel move within a tight cone only 100 to 130 feet (30 to 40 meters) thick, interacting with the magnetic field to produce an electric current that heats the liquid. This serves to damp the precession of the rotation axis. The damping causes the precession to lag behind the Moon as it orbits Earth. A measurement of the lag allowed Buffett to calculate the magnitude of the damping, and the magnetic field inside the outer core.
Buffett noted that the calculated field — 25 Gauss — is an average over the entire outer core. The field is expected to vary with position.
"I still find it remarkable that we can look to distant quasars to get insights into the deep interior of our planet," Buffett said.
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i love so much "quantum loops" and that is about it!
Physicists from the Faculty of Physics, University of Warsaw have put forward -- on the pages of Physical Review D -- a new theoretical model of quantum gravity describing the emergence of space-time from the structures of quantum theory. It is not only one of the few models describing the full general theory of relativity advanced by Einstein, but it is also completely mathematically consistent. "The solutions applied allow to trace the evolution of the Universe in a more physically acceptable manner than in the case of previous cosmological models," explains Prof. Jerzy Lewandowski from the Faculty of Physics, University of Warsaw (FUW).
While the general theory of relativity is applied to describe the Universe on a cosmological scale, quantum mechanics is applied to describe reality on an atomic scale. Both theories were developed in the early 20th century. Their validity has since been confirmed by highly sophisticated experiments and observations. The problem lies in the fact that the theories are mutually exclusive.
According to the general theory of relativity, reality is always uniquely determined (as in classical mechanics). However, time and space play an active role in the events and are themselves subject to Einstein's equations. According to quantum physics, on the other hand, one may only gain a rough understanding of nature. A prediction can only be made with a probability; its precision being limited by inherent properties. But the laws of the prevailing quantum theories do not apply to time and space. Such contradictions are irrelevant under standard conditions -- galaxies are not subject to quantum phenomena and quantum gravity plays a minor role in the world of atoms and particles. Nonetheless, gravity and quantum effects need to merge under conditions close to the Big Bang.
Traditional cosmological models describe the evolution of the Universe within the framework of the general theory of relativity itself. The equations at the core of the theory suggest that the Universe is a dynamic, constantly expanding creation. When theorists attempt to discover what the Universe was like in times gone by, they reach the stage where density and temperature in the model become infinite -- in other words, they lose their physical sense. Thus, the infinities may only be indicative of the weaknesses of the former theory and the moment of the Big Bang does not have to signify the birth of the Universe.
In order to gain at least some knowledge of quantum gravity, scientists construct simplified quantum models, known as quantum cosmological models, in which space-time and matter are expressed in a single value or a few values alone. For example, the model developed by Ashtekar, Bojowald, Lewandowski, Pawłowski and Singh predicts that quantum gravity prevents the increase of matter energy density from exceeding a certain critical value (of the order of the Planck density). Consequently, there must have been a contracting universe prior to the Big Bang. When matter density had reached the critical value, there followed a rapid expansion -- the Big Bang, known as the Big Bounce. However, the model is a highly simplified toy model.
The real answer to the mystery of the Big Bang lies in a unified quantum theory of matter and gravity. One attempt at developing such a theory is loop quantum gravity (LQG). The theory holds that space is weaved from one-dimensional threads. "It is just like in the case of a fabric -- although it is seemingly smooth from a distance, it becomes evident at close quarters that it consists of a network of fibres," describes Wojciech Kamiński, MSc from FUW. Such space would constitute a fine fabric -- an area of a square centimetre would consists of 1066 threads.
Physicists Marcin Domagała, Wojciech Kamiński and Jerzy Lewandowski, together with Kristina Giesel from the Louisiana State University (guest), developed their model within the framework of loop quantum gravity. The starting points for the model are two fields, one of which is a gravitational field. "Thanks to the general theory of relativity we know that gravity is the very geometry of space-time. We may, therefore, say that our point of departure is three-dimensional space," explains Marcin Domagała, PhD (FUW).
The second starting point is a scalar field -- a mathematical object in which a particular value is attributed to every point in space. In the proposed model, scalar fields are interpreted as the simplest form of matter. Scalar fields have been known in physics for years, they are applied, among others, to describe temperature and pressure distribution in space. "We have opted for a scalar field as it is the typical feature of contemporary cosmological models and our aim is to develop a model that would constitute another step forward in quantum gravity research," observes Prof. Lewandowski.
In the model developed by physicists from Warsaw, time emerges as the relation between the gravitational field (space) and the scalar field -- a moment in time is given by the value of the scalar field. "We pose the question about the shape of space at a given value of the scalar field and Einstein's quantum equations provide the answer," explains Prof. Lewandowski. Thus, the phenomenon of the passage of time emerges as the property of the state of the gravitational and scalar fields and the appearance of such a state corresponds to the birth of the well-known space-time. "It is worthy of note that time is nonexistent at the beginning of the model. Nothing happens. Action and dynamics appear as the interrelation between the fields when we begin to pose questions about how one object relates to another," explains Prof. Lewandowski.
Physicist from FUW have made it possible to provide a more accurate description of the evolution of the Universe. Whereas models based on the general theory of relativity are simplified and assume the gravitational field at every point of the Universe to be identical or subject to minor changes, the gravitational field in the proposed model may differ at different points in space.
The proposed theoretical construction is the first such highly advanced model characterized by internal mathematical consistency. It comes as the natural continuation of research into quantization of gravity, where each new theory is derived from classical theories. To that end, physicists apply certain algorithms, known as quantizations. "Unfortunately for physicists, the algorithms are far from precise. For example, it may follow from an algorithm that a Hilbert space needs to be constructed, but no details are provided," explains Marcin Domagała, MSc. "We have succeeded in performing a full quantization and obtained one of the possible models."
There is still a long way to go, according to Prof. Lewandowski: "We have developed a certain theoretical machinery. We may begin to ply it with questions and it will provide the answers." Theorists from FUW intend, among others, to inquire whether the Big Bounce actually occurs in their model. "In the future, we will try to include in the model further fields of the Standard Model of elementary particles. We are curious ourselves to find out what will happen," says Prof.
Lewandowski
i think lqc is the best theory that can describe what happend before big bang but it maybe false because i think linking general gravity to quantm mechanics is very hard and so imposible and it's too exciting theroy for me for that reason!if they can explain what happend after rewriting general geravity in quantumeic basis & is 100% possible with out having a paradox it will be such as a quack in physics and other science!
ScienceDaily (Jan. 11, 2011) — One of the strangest space objects ever seen is being scrutinized by the penetrating vision of NASA's Hubble Space Telescope. A mysterious, glowing green blob of gas is floating in space near a spiral galaxy. Hubble uncovered delicate filaments of gas and a pocket of young star clusters in the giant object, which is the size of our Milky Way galaxy.
The Hubble revelations are the latest finds in an ongoing probe of Hanny's Voorwerp (Hanny's Object in Dutch), named for Hanny van Arkel, the Dutch teacher who discovered the ghostly structure in 2007 while participating in the online Galaxy Zoo project. Galaxy Zoo enlists the public to help classify more than a million galaxies catalogued in the Sloan Digital Sky Survey. The project has expanded to include the Hubble Zoo, in which the public is asked to assess tens of thousands of galaxies in deep imagery from the Hubble Space Telescope.
In the sharpest view yet of Hanny's Voorwerp, Hubble's Wide Field Camera 3 and Advanced Camera for Surveys have uncovered star birth in a region of the green object that faces the spiral galaxy IC 2497, located about 650 million light-years from Earth. Radio observations have shown an outflow of gas arising from the galaxy's core. The new Hubble images reveal that the galaxy's gas is interacting with a small region of Hanny's Voorwerp, which is collapsing and forming stars. The youngest stars are a couple of million years old.
"The star clusters are localized, confined to an area that is over a few thousand light-years wide," explains astronomer William Keel of the University of Alabama in Tuscaloosa, leader of the Hubble study. "The region may have been churning out stars for several million years. They are so dim that they have previously been lost in the brilliant light of the surrounding gas."
Recent X-ray observations have revealed why Hanny's Voorwerp caught the eye of astronomers. The galaxy's rambunctious core produced a quasar, a powerful light beacon powered by a black hole. The quasar shot a broad beam of light in Hanny's Voorwerp's direction, illuminating the gas cloud and making it a space oddity. Its bright green color is from glowing oxygen.
"We just missed catching the quasar, because it turned off no more than 200,000 years ago, so what we're seeing is the afterglow from the quasar," Keel says. "This implies that it might flicker on and off, which is typical of quasars, but we've never seen such a dramatic change happen so rapidly."
The quasar's outburst also may have cast a shadow on the blob. This feature gives the illusion of a gaping hole about 20,000 light-years wide in Hanny's Voorwerp. Hubble reveals sharp edges around the apparent opening, suggesting that an object close to the quasar may have blocked some of the light and projected a shadow on Hanny's Voorwerp. This phenomenon is similar to a fly on a movie projector lens casting a shadow on a movie screen.
Radio studies have revealed that Hanny's Voorwerp is not just an island gas cloud floating in space. The glowing blob is part of a long, twisting rope of gas, or tidal tail, about 300,000 light-years long that wraps around the galaxy. The only optically visible part of the rope is Hanny's Voorwerp. The illuminated object is so huge that it stretches from 44,000 light-years to 136,000 light-years from the galaxy's core.
The quasar, the outflow of gas that instigated the star birth, and the long, gaseous tidal tail point to a rough life for IC 2497.
"The evidence suggests that IC 2497 may have merged with another galaxy about a billion years ago," Keel explains. "The Hubble images show in exquisite detail that the spiral arms are twisted, so the galaxy hasn't completely settled down."
In Keel's scenario, the merger expelled the long streamer of gas from the galaxy and funneled gas and stars into the center, which fed the black hole. The engorged black hole then powered the quasar, which launched two cones of light. One light beam illuminated part of the tidal tail, now called Hanny's Voorwerp.
About a million years ago, shock waves produced glowing gas near the galaxy's core and blasted it outward. The glowing gas is seen only in Hubble images and spectra, Keel says. The outburst may have triggered star formation in Hanny's Voorwerp. Less than 200,000 years ago, the quasar dropped in brightness by 100 times or more, leaving an ordinary-looking core.
New images of the galaxy's dusty core from Hubble's Space Telescope Imaging Spectrograph show an expanding bubble of gas blown out of one side of the core, perhaps evidence of the sputtering quasar's final gasps. The expanding ring of gas is still too small for ground-based telescopes to detect.
"This quasar may have been active for a few million years, which perhaps indicates that quasars blink on and off on timescales of millions of years, not the 100 million years that theory had suggested," Keel says. He added that the quasar could light up again if more material is dumped around the black hole.
Keel is presenting his results on Jan. 10, 2011, at the American Astronomical Society meeting in Seattle, Wash.
http://www.sciencedaily.com/releases...0110090425.htm
ویرایش توسط X-BLACKHOLE : 01-15-2011 در ساعت 03:25 PM
Hi There! I hope all of us have a snowy day full of fun & pleasure these days
Thank X_BACHHOLE for His/Hertopic
I found some other sources about your topic
but i couldn't find various pictures about that
. If u find any other pics please paste it here.
The space odditywas spied in 2007 by Dutch high-school teacher
Hanny van Arkel while participating in the online Galaxy Zoo project. The cosmic blob, called Hanny's Voorwerp (Hanny's Object in Dutch), appears to be a solitary green island floating near a normal-looking spiral galaxy, called IC 2497. Since the discovery, puzzled astronomers have used a slew of telescopes, including X-ray and radio observatories, to help unwrap the mystery. Astronomers found that Hanny's Voorwerp is the only visible part of a 300-light-year-long gaseous streamer stretching around the galaxy. The greenish Voorwerp is visible because a searchlight beam of light from the galaxy's core illuminated it. This beam came from a quasar, a bright, energetic object that is powered by a black hole. An encounter with another galaxy may have fed the black hole and pulled the gaseous streamer from IC 2497
Now, with the help of NASA's Hubble Space Telescope, astronomers have uncovered pocket of young star clusters (colored yellow-orange in the image) at the tip of the green-colored Hanny's Voorwerp. Hubble also shows that gas flowing from IC 2497 .(the pinkish object with the swirling spiral arms) may have instigated the star birth by compressing the gas in Hanny's Voorwerp
hi dear planetstruck
also i hope that you and your clan have a pleasurable snowy winter with funny
i'm so sorry.
i don't have more portrayal for this news that i inscribed .
but i guesstimate that this portrayal that attached to this news is manufacture and it is n't real portrayal .
ویرایش توسط planetstruck : 04-11-2011 در ساعت 10:18 AM دلیل: Correcting dictation
See asteroid profiles from recent occultations here
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ASTEROID OCCULTATION VIDEOS*
1-10-second MPG format (1.8 Meg) GPS time inserted video clip of occultation by 1587 Kahrstedt, 10-20-04.
2- 16-second AVI video clip (1.6 Meg), of occultation by 828 Lindemania, 11-10-02.
3- 372 Palma January 26, 2007. From Tehama, California, 13.5 second event.
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*Videos by Richard Nugent
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Hi my astronomical friends.
I propose that these videos are interesting to watch. I think pretty.
Best regards / Mohammad Reza Sadeghian
ویرایش توسط planetstruck : 04-11-2011 در ساعت 09:47 AM دلیل: Replacing words,Correcting Grammar poits
همیشه مراقب اشتباه دوم باش!
اشتباه اول حق توست...!
! Hi
Thanks
............................So do u
.I strongly agree with u cause I searched but there weren’t any real pics of ur news
first newssource:www.space.com
the sky event on february
Full Moon, 3:36 a.m.
The Full Moon of February is usually known as the Wolf Moon. In Algonquian it is called Snow Moon. Other names are Hunger Moon, Storm Moon, and Candles Moon.
In Hindi it is known as Magh Poornima. Its Sinhala (Buddhist) name is Navam Poya. The Full moon rises around sunset and sets around sunrise, the only night in the month when the moon is in the sky all night long. The rest of the month, the moon spends at least some time in the daytime sky.
Thu., February 24
Last Quarter Moon, 6:26 p.m.
The Last or Third Quarter Moon rises around 2 a.m. and sets around 11 a.m. It is most easily seen just after sunrise in the southern sky.
Observing Highlights
Fri., February 11, early evening
Moon close to the Pleiades
The First Quarter Moon passes just south of the brightest star cluster in the sky, the Pleiades (Messier 45) in Taurus.
Mon., February 14, 3 a.m.
Moon close to Messier 35
The waxing gibbous Moon passes close to the open cluster Messier 35 in Gemini.
Sun., February 20–Sat., March 5
Zodiacal Light
Visible in the west after evening twilight, the faint glow of interplanetary dust particles.
Planets
Mercury is too close to the Sun all month to be observed. Superior conjunction is on February 25.
Venus is a brilliant “morning star” all month.
Mars is too close to the Sun to be observed. It is in conjunction with the Sun on February 4.
Jupiter is in the western sky in the early evening, setting around 9 p.m. It spends most of the month in Pisces, but begins a brief visit to the constellation Cetus on February 24. Yes, Cetus!
Saturn rises around 10 p.m. and is visible the rest of the night in Virgo. Its rings have returned to their usual glory after being on edge for the last two years.
Uranus is in Pisces all month. It sets around 8:30 p.m.
Neptune is too close to the Sun to be observed. It is in conjunction with the Sun on February 17.
Notice that no less that three planets are in conjunction with the Sun this month.
February 09, 2011Hi there
.As I connected 2 the internet today in the morning, I found a news in yahoo which makes meshocked
.Now I wanna put it here 2 inform u
The latest news about a disputed report of a 900-foot asteroid's threat to Earth prompts a search for answers
Who says the world is only full of bad news? NASA has largely dismissed a Russian report that an asteroid larger than two football fields could hit Earth by 2036. In other words, you can relax.Known as "99942 Apophis," the 900-foot-long asteroid has had the attention of scientists for some time. According to an article from SPACE.com, back in 2004, NASA scientists announced that Apophis could hit the planet in 2029. But, after further number crunching, that prediction was later retracted
The asteroid hurtled back into the news when Russia recently predicted 99942 Apophis may hit Earth on April 13, 2036. NASA acknowledges that there is a chance this may happen, but it is far from likely. Donald Yeomans, who heads up NASA's Near-Earth Object Program Office, estimates the odds at around 1 in 250,000. And, don't worry — NASA does have a backup plan. Should the need arise, the space agency will construct machinery to change the asteroid's orbit
The Russian scientists are also hedging their bets. Professor Leonid Sokolov of St. Petersburg State University remarked that 99942 Apophis would most likely disintegrate before hitting Earth
Still, a chance is a chance, and Web searchers immediately sought more information on the errant asteroid. Online lookups for "99942 Apophis" jumped sharply while "pictures of asteroids" and "apophis nasa report" also posted strong spikes in the Search box
And while the odds of 99942 Apophis "hitting home" are blissfully slim, there are some in the scientific community who believe its high time for "Earth protection strategies" just in case. Discovery.com lists several theories as to how best tackle any objects that might be on a collision course with EarthOdds are we'll never need them. But it's better to be safe than to end up in a situation that resembles a Michael Bay movie.
ویرایش توسط planetstruck : 02-26-2011 در ساعت 10:08 AM
!Always be a first-rate version of yourself, instead of a second-rate version of somebody else
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