منتدي شادوهان الام

البالبالبا

Admin — Thu, 30 May 2013 16:31:04 GMT

بسم الله الرحمن الرحيم

اما بعد كما وعدتكم بأن احضر لكم استيلات واضافات بس صراحه المجله ديه انتم اتفجئتم منها

بس احب افهم المبتدئ

اقسم بالله المجله ديه بتنباع بفلوس لأن المجله ديه فيها السكربت جاهز وكمان استيلات جاهزه واضافات بقيمه 650 دولار

بس مش مشكله

ثاني شئ ده نسخه من موقعي بدليل المواضيع والاخبار

مركز رفع شادوهان

المهم بقي الفقرات

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مشاكل وحلول

الدرس الاول

الدرس الثاني

الدرس الثالث

الدرس الرابع

الدرس الخامس

الدرس السادس

الدرس السابع

الاستيلات

قالب العيد من جوملا العرب

كل عام وانتم بخير أمتنا الاسلامية وكل عام وانتم إلى الله أقرب نقدم اليكم الهدية الثانية لهذا العيد بقالب العيد لعامنا الهجري 1430 وهو محاكاة لاستايل احدى المنتديات العربية .

هذا القالب يعتبر من القوالب ذات الألوان الطاغية بحيث يحتوي على ..

هيدر مصور يمكن التعديل عليه وكتابة اسم موقعك .
قائمة منسدلة رائعة .
22 مكان موديل لتنويع الموديلات في موقعك مع امكانية تغيير شكل الموديل .
تصميم جذاب مريح للعين .
متوافق مع جميع المتصفحات الرئيسية حتى ie6, ie7.

تحميل القالب

قالب متنافسون لا أعداء
التحميل

القالب الرمضاني الثاني .. من جوملا العرب

القالب الرمضاني الثاني من جوملا العرب .. هذه المرة يحمل عبق عربي خالص وتصميم مختلف .. حيث فاجأنا مطور باستايلات رمضانية رائعة فكان واجبنا تحويل احدها الى جوملا وهذا هو استايل ليالي رمضان من مطور محول الى قالب جوملا العرب الخامس .. والثاني لرمضان مع كافة المميزات لقوالب جوملا العرب , فهذا القالب يحتوي على ..

هيدر فلاشي رائع مأخوذ من هيدر مطور ووضع عليه بعض التأثيرات الجديدة .
قائمة منسدلة رائعة .
22 مكان موديل لتنويع الموديلات في موقعك مع امكانية تغيير شكل الموديل .
تصميم جذاب مريح للعين .
ايقونات إسلامية للمواضيع والقوائم .

التحميل

قالب News Pro الإخباري المتطور

هذا القالب من شركة JoomlaXtc وهو الأفضل الأجدر بأن يكون موقعا إخبارياً لما يحتويه من إضافات برمجية رائعة جدا وتأثيرات خيالية داخل القالب وسنشاهدها بالتفصيل معاً في هذا المقال لشرح المميزات

تصميم خفيف جدا قليل من الصور التجميلة .
كثير من الابداعات البرمجية في الموديلات والاضافات البرمجية .
موديلات السلايدشو وعرض الفيديوهات والتغطيات الحية .

التحميل

قالب رمضان الأول .. القالب الرابع لجوملا العرب النسخة:1.0

اكمالا لمشوار حصريات جوملا العرب في رمضان .. يقدم لكم الموقع قالب رمضان الأول وهو عبارة عن قالب بسيط يتميز ب

هيدر فلاشي بارتفاع 270 بيكسل وعرض الصفحة كاملة .
قائمة منسدلة ذهبية رائعة .
22 مكان موديل لتنويع الموديلات في موقعك .
تصميم بسيط وخلفية ثابتة طول الصفحة .

التحميل

انتظروني مع استيلات اخري

ولاحظو ان التحميل مباشر

يالا علي الاضافات

هيا اقسام

Dark EnrgY

Admin — Fri, 18 Jan 2013 17:03:37 GMT

The discovery in 1998 that the Universe is actually speeding up its expansion was a total shock to astronomers. It just seems so counter-intuitive, so against common sense. But the evidence has become convincing.

The evidence came from studying distant Type Ia supernovae. This type of supernova results from having a white dwarf star in a binary system. Matter transfers from the normal star to the white dwarf until the white dwarf attains a critical mass (the Chandrasekhar limit) and undergoes a thermonuclear explosion. Because all white dwarfs achieve the same mass before exploding, they all achieve the same luminosity and can be used by astronomers as "standard candles." Thus by observing their apparent brightness, astronomers can determine their distance using the 1/r² law.

By knowing the distance to these supernovae, we know how long ago they occurred. In addition, the light from the supernova has been red-shifted by the expansion of the Universe. By measuring this redshift from the spectrum of the supernova, astronomers can determine how much the Universe has expanded since the explosion. By studying many supernovae at different distances, astronomers can piece together a history of the expansion of the Universe.

In the 1990's two teams of astronomers, the Supernova Cosmology Project (Lawrence Berkeley National Laboratory) and the High-Z Supernova Search (international), were looking for distant Type Ia supernovae in order to measure the expansion rate of the Universe with time. They expected that the expansion would be slowing, which would be indicated by the supernovae being brighter than their redshifts would indicate. Instead, they found the supernovae to be fainter than expected. Hence, the expansion of the Universe was accelerating!

In addition, measurements of the cosmic microwave background indicate that the Universe has a flat geometry on large scales. Because there is not enough matter in the Universe -- either ordinary or dark matter -- to produce this flatness, the difference must be attributed to a "dark energy". This same dark energy causes the acceleration of the expansion of the Universe. In addition, the effect of dark energy seems to vary, with the expansion of the Universe slowing down and speeding up over different times.

Astronomers know dark matter is there by its gravitational effect on the matter that we see, and there are ideas about the kinds of particles it must be made of. By contrast, dark energy remains a complete mystery. The name "dark energy" refers to the fact that some kind of "stuff" must fill the vast reaches of mostly empty space in the Universe in order to be able to make space accelerate in its expansion. In this sense, it is a "field" just like an electric field or a magnetic field, both of which are produced by electromagnetic energy. But this analogy can only be taken so far, because we can readily observe electromagnetic energy via the particle that carries it, the photon.

Some astronomers identify dark energy with Einstein's Cosmological Constant. Einstein introduced this constant into his general relativity when he saw that his theory was predicting an expanding universe, which was contrary to the evidence for a static universe that he and other physicists had in the early 20th century. This constant balanced the expansion and made the Universe static. With Edwin Hubble's discovery of the expansion of the Universe, Einstein dismissed his constant. It later became identified with what quantum theory calls the energy of the vacuum.

In the context of dark energy, the cosmological constant is a reservoir which stores energy. Its energy scales as the Universe expands. Applied to the supernova data, it would distinguish effects due to the matter in the Universe from those due to the dark energy. Unfortunately, the amount of this stored energy required is far more than observed and would result in very rapid acceleration -- so much so that the stars and galaxies would not form. Physicists have suggested a new type of matter, "quintessence," which would fill the Universe like a fluid which has a negative gravitational mass. However, new constraints imposed on cosmological parameters by Hubble Space Telescope data rule out at least simple models of quintessence.

Other possibilities being explored are topological defects, time-varying forms of dark energy, or a dark energy that does not scale uniformly with the expansion of the Universe.

Light Curves, Spectra, and Images

Admin — Fri, 18 Jan 2013 16:58:00 GMT

Tools for All Astronomers

Because most of the objects that astronomers observe are so far away, we cannot touch them. Observing the light that they emit is often the only means we have of understanding them. Studying the light that comes from a source can tell us a great deal about what kind of object it is -- we can measure the energy of the light coming from the source, we can measure the amount of light coming from the source, and we can make an image of the source. If we graph the amount of light at different energies, we can make a spectrum. We can also measure the brightness of the source over time, making what is called a light curve. By making an image of the source, we see what it looks like.

The concept of an image is probably the most familiar -- telescopes like the Hubble Space Telescope produce many beautiful images. But images can also be made using light we can't see with our eyes, such as infrared or ultraviolet. Graphical data, like spectra and light curves, are very valuable to astronomers as well. Among other things, a spectrum can give us information about an object's composition, mass, and motion. A light curve can analyze short-term or long-term changes in the brightness of a source -- useful for bursting objects, binary systems of stars, and pulsars. Click on one of the below links to learn more about light curves, spectra, and images!

The History of Gamma-ray Astronomy

Admin — Fri, 18 Jan 2013 16:45:16 GMT

Long before experiments could detect gamma-rays emitted by cosmic sources, scientists had known that the Universe should be producing such high energy photons. Hard work by several brilliant scientists had shown us that a number of different processes which were occurring in the Universe would result in gamma-ray emission. These processes included cosmic ray interactions with interstellar gas, supernova explosions, and interactions of energetic electrons with magnetic fields. In the 1960s, we finally developed the ability to actually detect these emissions and we have been looking at them ever since!

Gamma-rays coming from space are mostly absorbed by the Earth's atmosphere. So gamma-ray astronomy could not develop until it was possible to get our detectors above all or most of the atmosphere, using balloons or spacecraft. The first gamma-ray telescope carried into orbit, on the Explorer XI satellite in 1961, picked up fewer than 100 cosmic gamma-ray photons. These appeared to come from all directions in the Universe, implying some sort of uniform "gamma-ray background". Such a background would be expected from the interaction of cosmic rays (very energetic charged particles in space) with gas found between the stars.

Additional gamma-ray experiments flew on the OGO, OSO, Vela, and Russian Cosmos series of satellites. However, the first satellite designed as a "dedicated" gamma-ray mission was the second Small Astronomy Satellite (SAS-2) in 1972. It lasted only seven months due to an electrical problem, but provided an exciting view into the high-energy Universe (sometimes called the 'violent' Universe, because the kinds of events in space that produce gamma-rays tend to be explosions, high-speed collisions, and such!). In 1975, the European Space Agency launched a similar satellite, COS-B, which operated until 1982. These two satellites, SAS-2 and COS-B, confirmed the earlier findings of the gamma-ray background, and also detected a number of point sources. However, the poor resolution of the instruments made it impossible to identify most of these point sources with individual stars or stellar systems.

Show me a movie about Dr. Compton

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The man seen in this image is Dr. Arthur Holly Compton. He won the Nobel Prize for Physics in 1927 for his work on the scattering of high-energy photons by electrons - which is something very basic to most gamma-ray detection techniques. The Compton Gamma-Ray Observatory was named in his honor after it went into orbit in April 1991. It continued to operate until June 2000, giving scientists the best look they have ever gotten of the gamma-ray universe.

So what are gamma-rays and what can they tell us about the cosmos? Gamma-rays are the most energetic form of electromagnetic radiation, with over 10,000 times more energy than visible light photons. If you could see gamma-rays, the night sky would look strange and unfamiliar. The familiar sights of constantly shining stars and galaxies would be replaced by something ever-changing. Your gamma-ray vision would peer into the hearts of solar flares, supernovae, neutron stars, black holes, and active galaxies. Gamma-ray astronomy presents unique opportunities to explore these exotic objects. By exploring the universe at these high energies, scientists can search for new physics, testing theories and performing experiments which are not possible in earth-bound laboratories.

Show me a movie about gamma-ray astronomy!

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Gamma-Ray Observing Platforms

Most gamma-rays are absorbed by the Earth's atmosphere. Thus, cosmic gamma-rays are typically observed from high-altitude balloons and satellites.

Tell me more about how scientists "see" gamma-rays

Balloons

Balloons are often the ideal vehicle for science payloads. At energies greater than about 30 keV, hard (more energetic) X-ray and gamma-ray astronomy can be done from balloons. At these high photon energies, being above 99.7 % of the Earth's atmosphere (which is where you are with a balloon float altitude of 40 km) is as good as being above 100 % of the atmosphere!

Balloon-borne hard X-ray and gamma-ray imaging telescopes provided the first images of the sky in the energy range 20-1000 keV. They discovered black hole candidate sources in the galactic center region, first imaged the cobalt-decay gamma-rays from the spectacular supernova SN 1987A, and provided the first capability to localize (and thus study) high-energy sources for comparison with more detailed lower-energy X-ray observations.

In the past, balloon flights typically remained at float altitude from several hours to one or two days, at best. Nowadays, however, there are balloons called Long-Duration Balloons (or LDBs) which typically stay aloft for 3 weeks or more. They can carry a payload of over 2000 kg, with active experiment areas of up to 30 m²! Perhaps just as importantly in the modern era, balloon experiments are relatively inexpensive (when compared to satellite missions). Ballooning today is not the same as ballooning in the past!

Filling the balloon for a flight of the GRIP payload

Satellites

Satellites provide an excellent platform from which to observe cosmic gamma-rays. One reason is that the intensity, or flux, of cosmic gamma-rays arriving at the Earth is very low when compared to other sources of high-energy photons. Thus, staying in orbit observing for many months or years allows scientists to gather more and more cosmic gamma-rays. The more "real" gamma-rays they collect, the better their data analysis can be. Since 1961 when the first satellite went into orbit carrying a detector sensitive to energies greater than 50 MeV, many satellites have flown to observe cosmic gamma-rays. While the first satellite, Explorer-11 detected only 22 cosmic gamma-rays, 621 events attributable to cosmic gamma-rays were detected by the OSO-3 satellite in 1967. Since then, the sensitivity of the detectors has increased by factors of 1000! This has allowed scientists to make many fascinating discoveries in the high-energy universe. For example, they have mapped the diffuse gamma-ray background, found gamma-ray pulsars, and discovered the still-unexplained cosmic gamma-ray bursts! NASA's Wind satellite, pictured on the right, has 2 instruments which have been monitoring these bursts since 1994.

Targ

ets of Gamma-ray Observations

Observing the Universe in gamma-rays allows us to examine things which are happening that cannot be seen with ordinary telescopes and, yet, which are very important in helping us to understand how matter and radiation interact with each other. This is especially true for understanding their interaction under extreme conditions, such as where temperatures are hundreds of millions of degrees, matter is very dense, or magnetic fields are very strong.

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Admin — Sun, 21 Oct 2012 20:40:45 GMT

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