Just Speak In English_Topic: No topic

[Vahed]

Thanks...i will do that

[Parnyan]

hi dears
Nebula
Nebula, a localized mass of the gases and finely divided dust particles that are spread throughout interstellar space. Before the invention of the telescope, the term nebula (Latin, “cloud”) was applied to all celestial objects of a diffuse appearance. As a result, many objects now known to be star clusters or galaxies were called nebulae.

Nebulae exist within other galaxies as well as in our own, the Milky Way. They are classified as planetary nebulae, supernova remnants, and diffuse nebulae, including reflecting, emission, and dark nebulae. Small, very bright nebulae known as Herbig-Haro objects are found in dense interstellar clouds, and are probably the products of gas jets expelled by new stars in the process of formation.

Planetary nebulae, or planetaries, are so called because many of them superficially resemble planets through telescopes. They are actually shells of material that an old star of average mass sheds during a late, red giant stage in its evolution, before becoming a white dwarf. The Ring Nebula in the constellation Lyra, a typical planetary, has a rotational period of 132,900 years and a mass calculated to be about 14 times that of the Earth's sun. Several thousand planetaries have been discovered in the Milky Way. More spectacular but fewer in number are nebulae that are the fragments of supernova explosions, perhaps the most famous of which is the Crab Nebula in Taurus, now fading at the rate of about 0.4 per cent per year. Nebulae of this kind are strong emitters of radio waves, as a result of the explosions that formed them and the probable pulsar remnants of the original star.

Diffuse nebulae are extremely large, often many light years wide, with no definite outline and a tenuous, cloud-like appearance. They are either luminous or dark. The former shine as a result of the light of neighbouring stars. They include some of the most striking objects in the sky, such as the Great Nebula in Orion (the middle “star” in the Sword). The tremendous streams of matter in the diffuse nebulae are intermingled in violent, chaotic currents. Many thousands of luminous nebulae are known. Spectral studies show that light emanating from them consists of reflected starlight and also, in so-called emission nebulae, of stimulated radiation coming from ionized gases and dust in the nebulae.

Dark, diffuse nebulae are observed as nonluminous or faintly luminous clouds, obscuring portions of the Milky Way. They are too distant from the stimulation of neighbouring stars to reflect or emit much light of their own. One of the most famous dark nebulae is the Horsehead Nebula in Orion, so named after the shape of the dark mass silhouetted in front of a more luminous nebular region. The longest dark rift observed on photographic plates of the star clouds of the Milky Way is a succession of dark nebulae. Both dark and luminous nebulae are considered likely sites for the processes of dust-cloud condensation that lead to the formation of new stars.

[shahrzad2006]

hi my dear friends
i miss you, it has been a long time sience i wrote here .well finally my exams finished but my teachers doublicated our homeworks so i can't find time. so please forgive me i know i 'm not on my words.
bbye

[shahrzad2006]

THE HAPPIEST DAY, THE HAPPIEST HOUR

by Edgar Allan Poe

The happiest day- the happiest hour
My sear'd and blighted heart hath known,
The highest hope of pride and power,
I feel hath flown.

Of power! said I? yes! such I ween;
But they have vanish'd long, alas!
The visions of my youth have been-
But let them pass.

And, pride, what have I now with thee?
Another brow may even inherit
The venom thou hast pour'd on me
Be still, my spirit!

The happiest day- the happiest hour
Mine eyes shall see- have ever seen,
The brightest glance of pride and power,
I feel- have been:

But were that hope of pride and power
Now offer'd with the pain
Even then I felt- that brightest hour
I would not live again:

For on its wing was dark alloy,
And, as it flutter'd- fell
An essence- powerful to destroy
A soul that knew it well.

[Vahed]

thanks ...thanks ...thanks! really thank you specially dear parnyan & Shahrzad & amin pleas go on it!

[Parnyan]

White dwarf
White Dwarf, very small, dense, hot star, the end point in the evolution of a star such as the Sun. White dwarfs have masses similar to that of the Sun, but diameters about that of the Earth; hence their densities are extremely high, typically many tonnes per cubic centimetre. To reach such densities, the matter of which they are composed must be in a so-called degenerate state, in which the normal structure of the atom breaks down and the electrons and protons are packed as closely together as physically possible. Stars become white dwarfs after they have swollen up into red giants and lost their outer layers, forming planetary nebulae; the white dwarf is the exposed core of the star, now no longer producing energy by nuclear reactions. Although white dwarfs are very hot when they are first formed, with surface temperatures up to 100,000 K (180,000° F), being so small they are inevitably very faint, with luminosities around a thousandth of that of the Sun. White dwarfs gradually cool and fade to invisibility over billions of years. The greatest possible mass for a white dwarf is 1.4 times that of the Sun, the so-called Chandrasekhar limit.

[Parnyan]

North Star
North Star or Pole Star, conspicuous star in the northern hemisphere, the closest to the point towards which the axis of the Earth is directed, thus roughly marking the location of the celestial North Pole. The Pole Star has been used by navigators throughout recorded history and is still used for determining true azimuth and latitude. The positions of the celestial poles change as the Earth's axis moves with the Earth's precessional motion (seeEcliptic), and as the celestial North Pole assumes different positions relative to the constellations, different stars become the Pole Star.
During the past 5,000 years the position of the celestial North Pole has moved from the star Thuban, or Alpha () Draconis, in the constellation Draco, to within one degree of the bright star Polaris, also known as Alpha () Ursae Minoris, in the constellation Ursa Minor (Little Bear). Polaris is a multiple star of the second magnitude, and is located at a distance of about 300 light years from the Earth. It is easy to locate in the sky because two easily identifiable stars in the constellation Ursa Major (the Great Bear), which are called the Pointers, point to the star Polaris.
In the year 7500 the brightest star in the constellation Cepheus, Alpha () Cephei, will mark the pole, and in the year 15000 the star Vega, in the constellation Lyra, will be the pole star. About 9,000 years after that, Polaris will again become the North Star

[Parnyan]

hi dears
Ursa Major
Ursa Major, the Great Bear, a conspicuous constellation in the northern celestial hemisphere, near the North Pole. It was known to the ancient Greeks as the Bear and the Wagon and to the Romans as the Great Bear or as the Septentriones (Seven Ploughing Oxen). The seven brightest stars of the constellation form an easily identified outline, resembling a giant ladle. In Europe, the pattern is known as the Plough, as Charles's (Charlemagne's) Wain, or as the Wagon; in the United States it is the Big Dipper; among the Hindus, it represents the seven rishis, or holy sages of ancient times.
Of the seven stars constituting the Plough, six are of the second magnitude and one is of the third magnitude. Two of the second-magnitude stars, Alpha () and Beta (β) Ursae Majoris, point directly to the North Star, or Polaris, and hence are called the Pointers. At the bend of the “handle” is the readily apparent double star known as Mizar, or Zeta () Ursae Majoris. Mizar, the first double star discovered, consists of two components having magnitudes of 2.4 and 4, respectively. The brighter component was itself found in spectroscopic studies (1889) to be a double star; subsequently, in 1908, it was discovered that the other component is a spectroscopic double.

[Parnyan]

What happens when black holes collide?


It is possible for two black holes to collide. Once they come so close that they cannot escape each other's gravity, they will merge to become one bigger black hole. Such an event would be extremely violent. Even when simulating this event on powerful computers, we cannot fully understand it. However, we do know that a black hole merger would produce tremendous energy and send massive ripples through the space-time fabric of the Universe. These ripples are called gravitational waves.

Nobody has witnessed a collision of black holes yet. However, there are many black holes in the Universe and it is not preposterous to assume that they might collide. In fact, we know of galaxies in which two supermassive black holes move dangerously close to each other. Theoretical models predict that these black holes will spiral toward each other until they eventually collide.

Gravitational waves have never been directly observed. However, they are a fundamental prediction of Einstein's theory of general relativity. Detecting them would provide an important test of our understanding of gravity. It would also provide important new insights into the physics of black holes. Large instruments capable of detecting gravitational waves from outer space have been built in recent years. Even more powerful instruments are under construction. The moment they detect their first gravitational wave, you are sure to hear about it

[Vahed]

AGRICULTURE REPORT - October 8, 2006: Raising Chickens

This is the VOA Special English Agriculture Report.

Raising chickens or other birds for the eggs and meat they produce is a popular family and business activity almost everywhere in the world. The birds eat grain, seeds and grasses. They also eat small pieces of food that people throw away. Many of these materials would be wasted if the birds did not eat them. Chicken eggs and meat contain high quality protein and other substances important in the human diet.
For many centuries, chickens were allowed to run free to find food by themselves. Then people used fences to keep small groups of birds known as flocks from running away. After the chickens were kept inside a fence, people had to provide food for them.
Early in the last century, raising flocks of thousands of birds became a successful business for many people. But the size of these flocks caused some serious problems, including pollution caused by chicken waste.
Disease is one of the biggest problems in large flocks. The birds are kept close together all the time. So if one bird becomes sick, the sickness spreads. All the chickens in a flock can die from a serious disease. Diseases that affect chickens are different in different areas of the world. So medicines that have been successful in treating chickens in local areas should be used
People who raise chickens should try to prevent disease. Experts advise these steps: Feed the birds a balanced diet. This will help them resist infections. Do not add adult birds to your flocks. If you must add adult birds, keep them separate from the flock for five to fifteen days to make sure they are healthy.
Cover the floor of the buildings where the chickens are kept with material like straw, rice husks or sawdust. Change this material often.
After you sell the chickens, completely empty the building where they were kept. Clean and wash the building. Then leave it empty for four weeks before putting in new chickens.
Diseases affecting birds are not simple to understand and treat, so expert medical advice is important. You can get more information about caring for chickens and other birds from the organization Volunteers in Technical Assistance. Computer users can reach VITA through the Internet at w-w-w dot v-i-t-a dot o-r-g.