Vortex

A vortex (plural: vortices) is a spinning, often turbulent, flow of fluid. Any spiral motion with closed streamlines is vortex flow. The motion of the fluid swirling rapidly around a center is called a vortex. The speed and rate of rotation of the fluid are greatest at the center, and decrease progressively with distance from the center.

Vortex created by the passage of an aircraft wing, revealed by colored smoke

Properties

Vortices display some special properties:
The fluid pressure in a vortex is lowest in the center where the speed is greatest, and rises progressively with distance from the center.This is in accordance with Bernoulli's Principle. The core of a vortex in air is sometimes visible because of a plume of water vapor caused by condensation in the low pressure of the core. The spout of a tornado is a classic and frightening example of the visible core of a vortex. A dust devil is also the core of a vortex, made visible by the dust drawn upwards by the turbulent flow of air from ground level into the low pressure core.
The core of every vortex can be considered to contain a vortex line, and every particle in the vortex can be considered to be circulating around the vortex line. Vortex lines can start and end at the boundary of the fluid or form closed loops. They cannot start or end in the fluid. (See Helmholtz's theorems.) Vortices readily deflect and attach themselves to a solid surface. For example, a vortex usually forms ahead of the propeller disk or jet engine of a slow-moving airplane. One end of the vortex line is attached to the propeller disk or jet engine, but when the airplane is taxiing the other end of the vortex line readily attaches itself to the ground rather than end in midair. The vortex can suck water and small stones into the core and then into the propeller disk or jet engine.
Two or more vortices that are approximately parallel and circulating in the same direction will quickly merge to form a single vortex. The circulation of the merged vortex will equal the sum of the circulations of the constituent vortices. For example, a sheet of small vortices flows from the trailing edge of the wing or propeller of an airplane when the wing is developing lift or the propeller is developing thrust. In less than one wing chord downstream of the trailing edge of the wing these small vortices merge to form a single vortex. If viewed from the tail of the airplane, looking forward in the direction of flight, there is one wingtip vortex trailing from the left-hand wing and circulating clockwise, and another wingtip vortex trailing from the right-hand wing and circulating anti-clockwise. The result is a region of downwash behind the wing, between the pair of wingtip vortices. These two wingtip vortices do not merge because they are circulating in opposite directions.
Vortices contain a lot of energy in the circular motion of the fluid. In an ideal fluid this energy can never be dissipated and the vortex would persist forever. However, real fluids exhibit viscosity and this dissipates energy very slowly from the core of the vortex. (See Rankine vortex). It is only through dissipation of a vortex due to viscosity that a vortex line can end in the fluid, rather than at the boundary of the fluid. For example, the wingtip vortices from an airplane dissipate slowly and linger in the atmosphere long after the airplane has passed. This is a hazard to other aircraft and is known as wake turbulence.

Observations
A vortex can be seen in the spiraling motion of air or liquid around a center of rotation. Circular current of water of conflicting tides form vortex shapes. Turbulent flow makes many vortices. A good example of a vortex is the atmospheric phenomenon of a whirlwind or a tornado or dust devil. This whirling air mass mostly takes the form of a helix, column, or spiral. Tornadoes develop from severe thunderstorms, usually spawned from squall lines and supercell thunderstorms, though they sometimes happen as a result of a hurricane.
In atmospheric physics, a mesovortex is on the scale of a few miles (smaller than a hurricane but larger than a tornado). [2] On a much smaller scale, a vortex is usually formed as water goes down a drain, as in a sink or a toilet. This occurs in water as the revolving mass forms a whirlpool. This whirlpool is caused by water flowing out of a small opening in the bottom of a basin or reservoir. This swirling flow structure within a region of fluid flow opens downward from the water surface.

Instances
1. In the hydrodynamic interpretation of the behaviour of electromagnetic fields, the acceleration of electric fluid in a particular direction creates a positive vortex of magnetic fluid. This in turn creates around itself a corresponding negative vortex of electric fluid.
2. Smoke ring : A ring of smoke which persists for a surprisingly long time, illustrating the slow rate at which viscosity dissipates the energy of a vortex.
3. Lift-induced drag of a wing on an aircraft.
4. The primary cause of drag in the sail of a sloop.
5. Whirlpool: a swirling body of water produced by ocean tides or by a hole underneath the vortex where the water would drain out, such as a bathtub. A large, powerful whirlpool is known as a maelstrom. In popular imagination, but only rarely in reality, can they have the dangerous effect of destroying boats. Examples are Scylla and Charybdis of classical mythology in the Straits of Messina, Italy; the Naruto whirlpools of Nankaido, Japan; the Maelstrom, Lofoten, Norway.
6. Tornado : a violent windstorm characterized by a twisting, funnel-shaped cloud. A less violent version of a tornado, over water, is called a waterspout.
7. Hurricane : a much larger, swirling body of clouds produced by evaporating warm ocean water and influenced by the Earth's rotation. Similar, but far greater, vortices are also seen on other planets, such as the permanent Great Red Spot on Jupiter and the intermittent Great Dark Spot on Neptune.
8. Polar vortex : a persistent, large-scale cyclone centered near the Earth's poles, in the middle and upper troposphere and the stratosphere.
9. Sunspot : dark region on the Sun's surface (photosphere) marked by a lower temperature than its surroundings, and intense magnetic activity.
10. The accretion disk of a black hole or other massive gravitational source.
11. Spiral galaxy : a type of galaxy in the Hubble sequence which is characterized by a thin, rotating disk. Earth's galaxy, the Milky Way, is of this type.

Gemstone

Sapphire
Sapphire (Greek: sappheiros) refers to gem varieties of the mineral corundum, an aluminium oxide (α-Al2O3), when it is a color other than red, in which case the gem would instead be a ruby. Trace amounts of other elements such as iron, titanium, or chromium can give corundum blue, yellow, pink, purple, orange, or greenish color. Pink-orange corundum are also sapphires, but are instead called padparadscha.
Because it is a gemstone, sapphire is commonly worn as jewelry. Sapphire can be found naturally, or manufactured in large crystal boules. Because of its remarkable hardness, sapphire is used in many applications, including infrared optical components, watch crystals, high-durability windows, and wafers for the deposition of semiconductors.

Sapphire from Madagascar

Natural sapphires
Sapphire is one of the two gem varieties of corundum, the other being the red ruby. Although blue is the most well known hue, sapphire is any color of corundum except red. Sapphire may also be colorless, and it also occurs in the non-spectral shades gray and black. Pinkish-orange sapphire is known as padparadscha.
The cost of natural sapphire varies depending on their color, clarity, size, cut, and overall quality as well as geographic origin. Significant sapphire deposits are found in Eastern Australia, Thailand, Sri Lanka, Madagascar, East Africa and in the United States at various locations (Gem Mountain) and in the Missouri River near Helena, Montana. Sapphire and rubies are often found together in the same area, but one gem is usually more abundant.

Blue sapphire
Color in gemstones breaks down into three components: hue, saturation, and tone. Hue is most commonly understood as the "color" of the gemstone. Saturation refers to the vividness or brightness or "colorfulness" of the hue, and tone is the lightness to darkness of the hue. Blue sapphire exists in various mixtures of its primary and secondary hues, various tonal levels (shades) and at various levels of saturation (brightness): the primary hue must, of course, be blue.
Blue sapphires are evaluated based upon the purity of their primary hue. Purple, violet and green are the normal secondary hues found in blue sapphires. Violet and purple can contribute to the overall beauty of the color, while green is considered a distinct negative. Blue sapphires with no more than 15% violet or purple are generally said to be of fine quality. Blue sapphires with any amount of green as a secondary hue are not considered to be fine quality. Gray is the normal saturation modifier or mask found in blue sapphires. Gray reduces the saturation or brightness of the hue and therefore has a distinctly negative effect.
The color of fine blue sapphires can be described as a vivid medium dark violet to purplish blue where the primary blue hue is at least 85% and the secondary hue no more than 15% without the least admixture of a green secondary hue or a gray mask. The 422.99 carats (84.60 g) Logan sapphire in the National Museum of Natural History, Washington D.C. is one of the largest faceted gem-quality blue sapphires in the world.

The 422.99 carats (84.60 g) blue Logan sapphire

Color change sapphire
A rare variety of sapphire, known as color change sapphire, exhibits different colors in different light. Color change sapphires are blue in outdoor light and purple under incandescent indoor light. Color changes may also be pink in daylight to greenish under fluorescent light. Some stones shift color well and others only partially, in that some stones go from blue to bluish purple. While color change sapphires come from a variety of locations, the gem gravels of Tanzania is the main source.
Certain synthetic color-change sapphires are sold as “lab” or “synthetic” alexandrite, which is accurately called an alexandrite simulant (also called alexandrium) since the latter is actually a type of chrysoberyl---an entirely different substance whose pleochroism is different and much more pronounced than color-change corundum (sapphire).

Treatments

Sapphires may be treated by several methods to enhance and improve their clarity and color. It is common practice to heat natural sapphires to improve or enhance color. This is done by heating the sapphires to temperatures between 500 and 1800 °C for several hours, or by heating in a nitrogen-deficient atmosphere oven for seven days or more. Low Tube heating is where the stone is placed in a ceramic pot over charcoal, in which a man blows air through a bamboo tube to the charcoal creating more heat. The stone becomes a more blue in color but loses some of the silk. When high heat temperatures are used, the stone loses all of the silk and becomes clear under magnification. Evidence of sapphire and other gemstones being subjected to heating goes back to, at least, Roman times. Un-heated stones are quite rare and will often be sold accompanied by a certificate from an independent gemological laboratory attesting to "no evidence of heat treatment".
Diffusion treatments are somewhat more controversial as they are used to add elements to the sapphire for the purpose of improving colors. Typically beryllium (Be) is diffused into a sapphire with very high heat, just below the melting point of the sapphire. Initially (c. 2000) orange sapphires were created with this process, although now the process has been advanced and many colors of sapphire are often treated with beryllium. It is unethical to sell beryllium-treated sapphires without disclosure, and the price should be much lower than a natural gem or one that has been enhanced by heat alone.
Treating stones with surface diffusion is generally frowned upon; as stones chip or are repolished/refaceted the 'padparadscha' colored layer can be removed. (There are some diffusion treated stones in which the color goes much deeper than the surface, however.) The problem lies in the fact that treated padparadschas are at times very difficult to detect, and they are the reason that getting a certificate from a reputable gemological lab (e.g. Gubelin, SSEF, AGTA, etc.) is recommended before investing in a padparadscha.
According to Federal Trade Commission guidelines, in the United States, disclosure is required of any mode of enhancement that has a significant effect on the gem's value

Extrasolar planet

Gliese 581 c

Gliese 581 c (pronounced /ˈɡliːzə/) or Gl 581 c is a "Super-Earth", a large extrasolar terrestrial planet, orbiting the red dwarf star Gliese 581. Assuming that the planet's mass is close to the lower limit determined by radial velocity measurements (the true mass is unknown), it was the smallest known extrasolar planet around a main sequence star, but on April 21, 2009, another planet orbiting Gliese 581, Gliese 581 e, was announced with an approximate mass of 1.9 earth masses, which is now the smallest known extrasolar planet around a main sequence star. Gliese 581 c generated interest because it was initially reported to be the first potentially Earth-like planet in the habitable zone of its star, with a temperature right for liquid water on its surface, and by extension, potentially capable of supporting extremophile forms of Earth-like life. However, further research on the potential effects of the planetary atmosphere casts doubt upon the habitability of Gliese 581 c and indicates that the fourth planet in the system, Gliese 581 d, is a better candidate for habitability. In astronomical terms, the Gliese 581 system is relatively close to Earth, at 20.3 light years (192 trillion km or 119 trillion miles) in the direction of the constellation of Libra. This distance, along with the declination and right ascension coordinates, give its exact location in our galaxy. It is identified as Gliese 581 by its number in the Gliese Catalogue of Nearby Stars; it is the 87th closest known star system to the Sun.


Discovery
The discovery of the planet by the team of Stéphane Udry University of Geneva's Observatory in Switzerland was announced on April 24, 2007. The team used the HARPS instrument (an echelle spectrograph) on the European Southern Observatory 3.6 m Telescope in La Silla, Chile, and employed the radial velocity technique to identify the planet's influence on the star. The Canadian-built MOST space telescope was used to conduct a follow-up study over the next six weeks. No transit was detected over this time, so a direct measurement of the planet has not yet been possible; however, the star's apparent magnitude changed very little, indicating that it provides a stable source of light and heat to Gliese 581 c.
The team released a paper of their findings dated April 27, 2007, published in the July, 2007 journal Astronomy and Astrophysics. In the paper they also announced the discovery of another planet in the system, Gliese 581 d, with a minimum mass of 7.7 Earth masses and a semi-major axis of 0.25 astronomical units.

Physical characteristics

Mass
The existence of Gliese 581 c and its mass have been measured by the radial velocity method of detecting extrasolar planets. The mass of a planet is calculated by the small periodic movements around a common centre of mass between the host star Gliese 581 and its planets. When all four planets are fit with a Keplerian solution, the minimum mass of the planet is determined to be 5.36 Earth masses.

Radius
Since Gliese 581 c has not been detected directly, there are no measurements of its radius. Furthermore, the radial velocity method used to detect it only puts a lower limit on the planet's mass, which means theoretical models of planetary radius and structure can only be of limited use. However, assuming a random orientation of the planet's orbit, the true mass is likely to be close to the measured minimum mass.

Scale comparison of the relative sizes of the Earth and Gliese 581c, assuming Gliese 581c is a rocky body with a mass close to the minimum mass determined by the radial velocity method.

Orbit
Gliese 581 c has an orbital period ("year") of 13 Earth days and its orbital radius is only about 7% that of the Earth, about 11 million km, while the Earth is 150 million kilometres from the Sun. Since the host star is smaller and colder than the Sun—and thus less luminous—this distance places the planet on the "warm" edge of the habitable zone around the star according to Udry's team. Note that in astrophysics, the "habitable zone" is defined as the range of distances from the star at which a planet could support liquid water on its surface: it should not be taken to mean that the planet's environment would be suitable for humans, a situation which requires a more restrictive range of parameters. A typical radius for an M0 star of Gliese 581's age and metallicity is 0.00128 AU, against the sun's 0.00465 AU. This proximity means that the primary star should appear 3.75 times wider and 14 times larger in area for an observer on the planet's surface looking at the sky than the Sun appears to be from Earth's surface.

Habitability and Climate
The study of Gliese 581 c by the von Bloh et al. team has been quoted as concluding "The super-Earth Gl 581c is clearly outside the habitable zone, since it is too close to the star. "The study by Selsis et al. claims even "a planet in the habitable zone is not necessarily habitable" itself, and this planet "is outside what can be considered the conservative habitable zone" of the parent star, and further that if there was any water there and it was lost when the red dwarf was a strong X-ray and EUV emitter, it could have surface temperatures ranging from 700 K to 1000 K (427 to 727 °C). Temperature speculations by other scientists are based on the temperature of (and heat from) the parent star Gliese 581 and have been calculated without factoring in the wide margin of error (96 °C/K) for the star's temperature of 3432 K to 3528 K.

Planetary habitable zones of the Solar System and the Gliese 581 system compared.

Source from Wikipedia

Nuclear Radiation

The release of radiation is a phenomenon unique to nuclear explosions. There are several kinds of radiation emitted; these types include gamma, neutron, and ionizing radiation, and are emitted not only at the time of detonation (initial radiation) but also for long periods of time afterward (residual radiation).

Initial Nuclear Radiation

Initial nuclear radiation is defined as the radiation that arrives during the first minute after an explosion, and is mostly gamma radiation and neutron radiation.
The level of initial nuclear radiation decreases rapidly with distance from the fireball to where less than one roentgen may be received five miles from ground zero. In addition, initial radiation lasts only as long as nuclear fission occurs in the fireball. Initial nuclear radiation represents about 3 percent of the total energy in a nuclear explosion.
Though people close to ground zero may receive lethal doses of radiation, they are concurrently being killed by the blast wave and thermal pulse. In typical nuclear weapons, only a relatively small proportion of deaths and injuries result from initial radiation.

Residual Nuclear Radiation

The residual radiation from a nuclear explosion is mostly from the radioactive fallout. This radiation comes from the weapon debris, fission products, and, in the case of a ground burst, radiated soil.
There are over 300 different fission products that may result from a fission reaction. Many of these are radioactive with widely differing half-lives. Some are very short, i.e., fractions of a second, while a few are long enough that the materials can be a hazard for months or years. Their principal mode of decay is by the emission of beta particles and gamma radiation.

Radiation Effects on Humans

Certain body parts are more specifically affected by exposure to different types of radiation sources. Several factors are involved in determining the potential health effects of exposure to radiation. These include:

1) The size of the dose (amount of energy deposited in the body)
2) The ability of the radiation to harm human tissue
3) Which organs are affected

The most important factor is the amount of the dose - the amount of energy actually deposited in your body. The more energy absorbed by cells, the greater the biological damage. Health physicists refer to the amount of energy absorbed by the body as the radiation dose. The absorbed dose, the amount of energy absorbed per gram of body tissue, is usually measured in units called rads. Another unit of radation is the rem, or roentgen equivalent in man. To convert rads to rems, the number of rads is multiplied by a number that reflects the potential for damage caused by a type of radiation. For beta, gamma and X-ray radiation, this number is generally one. For some neutrons, protons, or alpha particles, the number is twenty.

Hair

The losing of hair quickly and in clumps occurs with radiation exposure at 200 rems or higher.

Brain

Since brain cells do not reproduce, they won't be damaged directly unless the exposure is 5,000 rems or greater. Like the heart, radiation kills nerve cells and small blood vessels, and can cause seizures and immediate death.

Thyroid

The certain body parts are more specifically affected by exposure to different types of radiation sources. The thyroid gland is susceptible to radioactive iodine. In sufficient amounts, radioactive iodine can destroy all or part of the thyroid. By taking potassium iodide can reduce the effects of exposure.

Blood System

When a person is exposed to around 100 rems, the blood's lymphocyte cell count will be reduced, leaving the victim more susceptible to infection. This is often refered to as mild radiation sickness. Early symptoms of radiation sickness mimic those of flu and may go unnoticed unless a blood count is done.According to data from Hiroshima and Nagaski, show that symptoms may persist for up to 10 years and may also have an increased long-term risk for leukemia and lymphoma. For more information, visit Radiation Effects Research Foundation.

Heart

Intense exposure to radioactive material at 1,000 to 5,000 rems would do immediate damage to small blood vessels and probably cause heart failure and death directly.

Gastrointestinal Tract

Radiation damage to the intestinal tract lining will cause nausea, bloody vomiting and diarrhea. This is occurs when the victim's exposure is 200 rems or more. The radiation will begin to destroy the cells in the body that divide rapidly. These including blood, GI tract, reproductive and hair cells, and harms their DNA and RNA of surviving cells.

Reproductive Tract

Because reproductive tract cells divide rapidly, these areas of the body can be damaged at rem levels as low as 200. Long-term, some radiation sickness victims will become sterile.

Dose-rem Effects
5-20 Possible late effects; possible chromosomal damage.

20-100 Temporary reduction in white blood cells.

100-200 Mild radiation sickness within a few hours: vomiting,
diarrhea, fatigue; reduction in resistance to infection.

200-300 Serious radiation sickness effects as in 100-200 rem and
hemorrhage; exposure is a Lethal Dose to 10-35% of the
population after 30 days (LD 10-35/30).

300-400 Serious radiation sickness; also marrow and intestine
destruction; LD 50-70/30.

400-1000 Acute illness, early death; LD 60-95/30.

1000-5000 Acute illness, early death in days; LD 100/10.

Effects of Nuclear Weapons

The Fireball

The fireball, an extremely hot and highly luminous spherical mass of air and gaseous weapon residues, occurs within less than one millionth of one second of the weapon's detonation. Immediately after its formation, the fireball begins to grow in size, engulfing the surrounding air. This growth is accompanied by a decrease in temperature because of the accompanying increase in mass. At the same time the fireball rises, like a hot-air balloon. Within seven-tenth of one millisecond from detonation, the fireball from a 1-megaton weapon is about 134 meters across, and this increases to a maximum value of about 1.73 kilometers in 10 seconds. It is then rising at rate of 76 - 106 meters per second. After a minute, the fireball has cooled to such an extent that it no longer emits visible radiation. It has then risen roughly 7.2 kilometers from the point of burst.

Illustrated components of a nuclear explosion.

The Mushroom Cloud

As the fireball increases in size and cools, the vapors condense to form a cloud containing solid particles of the weapon debris, as well as many small drops of water derived from the air sucked into the rising fireball.

The early formation of the mushroom cloud.

Depending on the height of burst, a strong updraft with inflowing winds, called "afterwinds," are produced. These afterwinds can cause varying amount of dirt and debris to be sucked up from the earth's surface into the cloud. In an air burst with a moderate (or small) amount of dirt and debris drawn up into the cloud, only a relatively small proportion become contaminated with radioactivity. For a burst near the ground, however, large amounts of dirt and debris are drawn into the cloud during formation.

The color of cloud is initially red or reddish brown, due to the presence of nitrous acid and oxides of nitrogen. As the fireball cools and condensation occurs, the color changes to white, mainly due to water droplets (as in an ordinary cloud)

The cloud consists chiefly or very small particles of radioactive fiision products and weapon residues, water droplets, and larger particles of dirt and debris carried up by the afterwinds.

The eventual height reached by the radioactive cloud depends upon the heat energy of the weapon and upon the atmospheric conditions. If the cloud reaches the tropopause, about 9.6 - 12.87 kilometer above the Earth's surface, there is a tendency for it to spread out. But if sufficient energy remains in the radioactive cloud at this height, a portion of it will ascend into the more stable air of the stratosphere.

The mushroom cloud forming at the Nevada Test Site.

The cloud attains its maximum height after about 10 minutes and is then said to be "stabilized". It continue to grow laterally, however, to produce the characteristic mushroom shape. The cloud may continue to be visible for about and hour or more before being dispersed by the winds into the surrounding atmosphere where it merges with natural clouds in the sky.

Thermal Pulse Effects

One of the important differences between a nuclear and conventional weapon is the large proportion of a nuclear explosion's energy that is released in the form of thermal energy. This energy is emitted from the fireball in two pulses. The first is quite short, and carries only about 1 percent of the energy; the second pulse is more significant and is of longer duration (up to 20 seconds).

The thermal pulse charring the paint

The energy from the thermal pulse can initiate fires in dry, flammable materials, such as dry leaves, grass, old newspaper, thin dark flammable fabrics, etc. The incendiary effect of the thermal pulse is also substantially affected by the later arrival of the blast wave, which usually blows out any flames that have already been kindled. However, smoldering material can reignite later.

The major incendiary effect of nuclear explosions is caused by the blast wave. Collapsed structures are much more vulnerable to fire than intact ones. The blast reduces many structures to piles of kindling, the many gaps opened in roofs and walls act as chimneys, gas lines are broken open, storage tanks for flammable materials are ruptured. The primary ignition sources appear to be flames and pilot lights in heating appliances (furnaces, water heaters, stoves, etc.). Smoldering material from the thermal pulse can be very effective at igniting leaking gas.
Thermal radiation damage depends very strongly on weather conditions. Cloud cover, smoke, or other obscuring material in the air can considerably reduce effective damage ranges versus clear air conditions.

The energy from the thermal pulse can initiate fires in dry, flammable materials, such as dry leaves, grass, old newspaper, thin dark flammable fabrics, etc. The incendiary effect of the thermal pulse is also substantially affected by the later arrival of the blast wave, which usually blows out any flames that have already been kindled. However, smoldering material can reignite later.

Effects of the thermal pulse on clothing

Thermal radiation also affects humans both directly - by flash burns on exposed skin - and indirectly - by fires started by the explosion.

Kisah Nabi Yahya a.s

Nabi Yahya adalah seorang nabi dari Bani Israel. Pada ketika itu, ada tiga orang nabi yang dibangkitkan serentak, iaitu nabi Zakaria, Yahya dan nabi Isa. Nabi Zakaria seorang yang dihormati dikalangan kaumnya. Baginda adalah seorang tukang kayu. Baginda tidak dikurniakan zuriat hinggalah umurnya 90 tahun. Ketekunan Baginda berdoa memohon zuriat akhirnya diperkenankan Allah. Allah merakamkan kisah ini di dalam al-Quran di dalam surah al-Anbiya ayat 90;- "Lalu Kami perkenankan permintaannya, dan Kami berikan Yahya kepadanya, dan Kami jadikan isterinya berkesanggupan (untuk mengandung); sesungguhnya mereka telah berlumba-lumba dalam usaha-usaha kebaikan, dan mereka berdoa kepada Kami dengan pengharapan dan perasaan takut, dan mereka adalah orang-orang yang tunduk hatinya kepada Kami." Di dalam surah Maryam ayat ke 7, Allah mengatakan bahawa:- "Hai Zakaria!, sesungguhnya Kami menyampaikan berita gembira kepada engkau (akan beroleh) seorang anak laki-laki, namanya Yahya, yang belum Kami berikan sebelumnya nama yang serupa itu." Nabi Yahya pun lahir. Dia dilahirkan enam bulan sebelum Nabi Isa dilahirkan. Kedua-dua anak kecil ini iaitu Yahya dan Isa dibesarkan dengan pendidikan agama. Kedua-dua ini akhirnya dilantik menjadi Rasul. Mengenai Nabi Yahya, Allah telah menyatakan bahawa:- "Hai Yahya, ambilah al-Kitab (Taurat) itu dengan sungguh-sungguh. Dan Kami berikan kepadanya hikmah selagi ia masih anak-anak, dan rasa belas kasihan yang mendalam dari sisi Kami dan kesucian (dari dosa). Dan ia adalah seorang yang bertakwa, dan banyak berbakti kepada kedua orang tuanya, dan bukanlah ia orang yang sombong dan durhaka. Kesejahteraan atas dirinya pada hari ia diiahirkan, dan pada hari itu ia meninggal dan pada hari ia dibangkitkan kembali". Surah Maryam, Ayat 12-15 Nabi Yahya adalah seorang Nabi terkenal dengan seorang yang sangat penyayang. Baginda juga di sayangi bukan sahaja oleh manusia, malahan juga burung-burung dan haiwan. Bagi pandangan orang Kristian, nabi Yahya yang telah membaptiskan (mandi wajib) Nabi Isa di sungai Jordan. Di kalangan orang kristian, baginda dikenali sebagai John the Baptist. Ketika Nabi Isa telah diangkat ke langit, semua permasalahan kehidupan beragama telah dirujuk kepada Nabi Yahya. Raja Herod Agripa yang telah mengeluarkan arahan membunuh Isa akhirnya membuat angkara lagi. Kali ini, sang Raja telah menaruh hati kepada anak saudara perempuanya. Dia ingin memperisterikan anak saudaranya ini. Di dalam syaraiat, seseorang tidak boleh berkahwin dengan anak saudaranya sendiri. Hal ini ditegah oleh Nabi Yahya a.s. Baginda diperintahkan untuk mengubah hukum ini ataupun hukuman bunuh dikeluarkan sebagaimana perintah bunuh pada Isa a.s. Ini kerana ada sesetengah ahli kitab yang sanggup meminda hukum Allah ini. Nabi Yahya tetap denga pendiriannya, tidak akan mengubah hukum Allah. Akhirnya, pada satu malam, ketika baginda sedang beribadah, datanglah sekumpulan tentera upahan menyembelih baginda dan mencincang badannya. Kepalanya dihantar kepada Raja Herod Agripa sebagai bukti perintah telah dilaksana. Kepala ini kemudiannya di arak untuk menjadi ancaman sesiapa yang berani melawan raja. Kepala ini di arak hingga ke Damsyik. Kemudian seseorang telah mengambil kepala ini dan telah mengebumikannya di Damsyik. Sekarang, makam kepada Nabi Yahya ini ada di dalam masjid Umawi di Damsyiq Syria. Badannya yang dicincang dikebumikan sekitar Jerusalem. Kini, tidak ada orang yang tahu tempat sebenar makam ini terletak. Cuma, terdapat potongan tangan Nabi Yahya diambil dan disimpan di Gereja Virgin Marry. Tangan ini kemudiannya diambil dan dan diletakkan di bawah jagaan Gereja Koptik di Mesir. Pada ketika Sultan Salem 1 dari Khilafah Uthmaniah menawan Mesir, tangan ini diamanahkan kepada baginda. Kini, tangan Nabi Yahya ini ada disimpan di Muzium Topkapi di Istanbul Turki. Menziarahi Topkapi dan Masjid Umawai, menghubungkan pengetahuan mengenai satu tubuh yang dicerai-ceraikan kerana mempertahankan syariat ilahi. Di syurga nanti, seluruh para Nabi, para Siddiqin, para syuhada’ dan para solihin akan dikumpulkan. Akan diganti segala kepahitan mempertahankan agama ketika di dunia dengan kemanisan syurga yang kekal abadi. Sedangkan para penzalim di dunia, yang takabbur di dunia, akan disembamkan ke gaung neraka yang tidak tergambar dek akal. Semuanya terhina dan terazab lantaran apa yang telah mereka lakukan di dunia ini.