History Of Galaxy Classification

During the 18th and 19th centuries, Sir William Herschel and his son Sir John Herschel both observed that 'nebulae' came in a range of different shapes and sizes. Sir Wiliam attempted a classification based on brightness, form and size. Nebulae were either:
Sir John Herschel extended this classification system, making a clear distinction between galactic nebulae (what we now refer to as nebulae) and non-galactic nebulae (now referred to as galaxies).

As photography and spectroscopy improved the standard of observations, further classifications were attempted. In 1919, Curtis considered all nebulae to be either planetary, diffuse or spirals (at that time, less than 10% of photographed nebulae showed any spiral structure. Due to the great distances of the galaxies, it would have been difficult to resolve any spiral structure).

In the early 1920s, Edwin Hubble made observations of non-galactic nebulae with the 100-inch telescope at Mount Wilson Observatory, USA. Non-galactic did not mean the same as extragalactic - it only referred to nebulae that were away from the galactic plane (where most of the planetary and diffuse nebulae were seen). In 1925, Hubble reported that individual stars had been seen in M31 and M33, including novae and Cepheid variable stars. This led to the realisation that these objects were in fact collections of stars beyond the Milky Way. These remote stellar systems were galaxies. The term nebula now refers exclusively to galactic objects such as the gaseous clouds where stars are born (emission and reflection nebula) and the planetary nebulae produced by low to intermediate mass stars during the later stages of their lives.

The 'tuning fork' diagram was introduced by Hubble in 1925 as means of classifying extra-galactic nebulae as either elliptical (from circular to lenticular), spiral or barred spiral (in both cases, classed according to the size of the bulge and the amount of winding of the spiral arms);. The terms 'early' and 'late' (see galaxy types) are sometimes used to indicate which end of the tuning fork a galaxy is found (left=early, right=late), as Hubble thought his classification might indicate an evolutionary sequence. The tuning fork is no longer considered an evolutionary sequence, and these terms are now used only for historical reasons.

The modern classification of galaxies distinguishes between ellipticals, spirals, barred spirals and irregular galaxies. Spirals are further classified according to their luminosity class using a system introduced by van den Bergh in 1960. 

Solar system

Our solar system consists of an average star we call the Sun, the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. It includes: the satellites of the planets; numerous comets, asteroids, and meteoroids; and the interplanetary medium. The Sun is the richest source of electromagnetic energy (mostly in the form of heat and light) in the solar system. The Sun's nearest known stellar neighbor is a red dwarf star called Proxima Centauri, at a distance of 4.3 light years away. The whole solar system, together with the local stars visible on a clear night, orbits the center of our home galaxy, a spiral disk of 200 billion stars we call the Milky Way. The Milky Way has two small galaxies orbiting it nearby, which are visible from the southern hemisphere. They are called the Large Magellanic Cloud and the Small Magellanic Cloud. The nearest large galaxy is the Andromeda Galaxy. It is a spiral galaxy like the Milky Way but is 4 times as massive and is 2 million light years away. Our galaxy, one of billions of galaxies known, is traveling through intergalactic space.
The planets, most of the satellites of the planets and the asteroids revolve around the Sun in the same direction, in nearly circular orbits. When looking down from above the Sun's north pole, the planets orbit in a counter-clockwise direction. The planets orbit the Sun in or near the same plane, called the ecliptic. Pluto is a special case in that its orbit is the most highly inclined (18 degrees) and the most highly elliptical of all the planets. Because of this, for part of its orbit, Pluto is closer to the Sun than is Neptune. The axis of rotation for most of the planets is nearly perpendicular to the ecliptic. The exceptions are Uranus and Pluto, which are tipped on their sides.

Composition Of The Solar System

The Sun contains 99.85% of all the matter in the Solar System. The planets, which condensed out of the same disk of material that formed the Sun, contain only 0.135% of the mass of the solar system. Jupiter contains more than twice the matter of all the other planets combined. Satellites of the planets, comets, asteroids, meteoroids, and the interplanetary medium constitute the remaining 0.015%. The following table is a list of the mass distribution within our Solar System.

• Sun: 99.85%
• Planets: 0.135%
• Comets: 0.01% ?
• Satellites: 0.00005%
• Minor Planets: 0.0000002% ?
• Meteoroids: 0.0000001% ?
• Interplanetary Medium: 0.0000001% ?

Interplanetary Space

Nearly all the solar system by volume appears to be an empty void. Far from being nothingness, this vacuum of "space" comprises the interplanetary medium. It includes various forms of energy and at least two material components: interplanetary dust and interplanetary gas. Interplanetary dust consists of microscopic solid particles. Interplanetary gas is a tenuous flow of gas and charged particles, mostly protons and electrons -- plasma -- which stream from the Sun, called the solar wind.

The solar wind can be measured by spacecraft, and it has a large effect on comet tails. It also has a measurable effect on the motion of spacecraft. The speed of the solar wind is about 400 kilometers (250 miles) per second in the vicinity of Earth's orbit. The point at which the solar wind meets the interstellar medium, which is the "solar" wind from other stars, is called the heliopause. It is a boundary theorized to be roughly circular or teardrop-shaped, marking the edge of the Sun's influence perhaps 100 AU from the Sun. The space within the boundary of the heliopause, containing the Sun and solar system, is referred to as the heliosphere.
The solar magnetic field extends outward into interplanetary space; it can be measured on Earth and by spacecraft. The solar magnetic field is the dominating magnetic field throughout the interplanetary regions of the solar system, except in the immediate environment of planets which have their own magnetic fields.

The Terrestrial Planets

The terrestrial planets are the four innermost planets in the solar system, Mercury, Venus, Earth and Mars. They are called terrestrial because they have a compact, rocky surface like the Earth's. The planets, Venus, Earth, and Mars have significant atmospheres while Mercury has almost none. The following diagram shows the approximate distance of the terrestrial planets to the Sun.

The Jovian Planets

Jupiter, Saturn, Uranus, and Neptune are known as the Jovian (Jupiter-like) planets, because they are all gigantic compared with Earth, and they have a gaseous nature like Jupiter's. The Jovian planets are also referred to as the gas giants, although some or all of them might have small solid cores. The following diagram shows the approximate distance of the Jovian planets to the Sun.

• Formation of the Solar System.

Our Milkyway Galaxy
This image of our galaxy, the Milky Way, was taken with NASA's Cosmic Background Explorer's (COBE) Diffuse Infrared Background Experiment (DIRBE). This never-before-seen view shows the Milky Way from an edge-on perspective with the galactic north pole at the top, the south pole at the bottom and the galactic center at the center. The picture combines images obtained at several near-infrared wavelengths. Stars within our galaxy are the dominant source of light at these wavelengths. Even though our solar system is part of the Milky Way, the view looks distant because most of the light comes from the population of stars that are closer to the galactic center than our own Sun. (Courtesy NASA)

Our Milky Way Gets a Makeover
Like early explorers mapping the continents of our globe, astronomers are busy charting the spiral structure of our galaxy, the Milky Way. Using infrared images from NASA's Spitzer Space Telescope, scientists have discovered that the Milky Way's elegant spiral structure is dominated by just two arms wrapping off the ends of a central bar of stars. Previously, our galaxy was thought to possess four major arms.
This artist's concept illustrates the new view of the Milky Way, along with other findings presented at the 212th American Astronomical Society meeting in St. Louis, Mo. The galaxy's two major arms (Scutum-Centaurus and Perseus) can be seen attached to the ends of a thick central bar, while the two now-demoted minor arms (Norma and Sagittarius) are less distinct and located between the major arms. The major arms consist of the highest densities of both young and old stars; the minor arms are primarily filled with gas and pockets of star-forming activity.
The artist's concept also includes a new spiral arm, called the "Far-3 kiloparsec arm," discovered via a radio-telescope survey of gas in the Milky Way. This arm is shorter than the two major arms and lies along the bar of the galaxy.
Our sun lies near a small, partial arm called the Orion Arm, or Orion Spur, located between the Sagittarius and Perseus arms. (Courtesy NASA/JPL-Caltech)

Spiral Galaxy, NGC 4414
The majestic galaxy, NGC 4414, is located 60 million light-years away. Like the Milky Way, NGC 4414 is a giant spiral-shaped disk of stars, with a bulbous central hub of older yellow and red stars. The outer spiral arms are considerably bluer due to ongoing formation of young, blue stars, the brightest of which can be seen individually at the high resolution provided by the Hubble camera. The arms are also very rich in clouds of interstellar dust, seen as dark patches and streaks silhouetted against the starlight. (Courtesy NASA/STSCI)

Obliquity of the Eight Planets
This illustration shows the obliquity of the eight planets. Obliquity is the angle between a planet's equatorial plane and its orbital plane. By International Astronomical Union (IAU) convention, a planet's north pole lies above the ecliptic plane. By this convention, Venus, Uranus, and Pluto have a retrograde rotation, or a rotation that is in the opposite direction from the other planets. (Copyright 2008 by Calvin J. Hamilton)

The Solar System
During the past three decades a myriad of space explorers have escaped the confines of planet Earth and have set out to discover our planetary neighbors. This picture shows the Sun and all nine planets of the solar system as seen by the space explorers. Starting at the top-left corner is the Sun followed by the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. (Copyright 1998 by Calvin J. Hamilton)

Sun and Planets
This image shows the Sun and nine planets approximately to scale. The order of these bodies are: Sun, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. (Copyright Calvin J. Hamilton)

Jovian Planets
This image shows the Jovian planets Jupiter, Saturn, Uranus and Neptune approximately to scale. The Jovian planets are named because of their gigantic Jupiter-like appearance. (Copyright Calvin J. Hamilton)

The Largest Moons and Smallest Planets
This image shows the relative sizes of the largest moons and the smallest planets in the solarsystem. The largest satellites pictured in this image are: Ganymede (5262 km), Titan (5150 km), Callisto (4806 km), Io (3642 km), the Moon (3476 km), Europa (3138 km), Triton (2706 km), and Titania (1580 km). Both Ganymede and Titan are larger than planet Mercury followed by Io, the Moon, Europa, and Triton which are larger than the planet Pluto. (Copyright Calvin J. Hamilton)

Diagram of Portrait Frames
On February 14, 1990, the cameras of Voyager 1 pointed back toward the Sun and took a series of pictures of the Sun and the planets, making the first ever "portrait" of our solar system as seen from the outside. This image is a diagram of how the frames for the solar system portrait were taken. (Courtesy NASA/JPL)

All Frames from the Family Portrait
This image shows the series of pictures of the Sun and the planets taken on February 14, 1990, for the solar system family portrait as seen from the outside. In the course of taking this mosaic consisting of a total of 60 frames, Voyager 1 made several images of the inner solar system from a distance of approximately 6.4 billion kilometers (4 billion miles) and about 32° above the ecliptic plane. Thirty-nine wide angle frames link together six of the planets of our solar system in this mosaic. Outermost Neptune is 30 times further from the Sun than Earth. Our Sun is seen as the bright object in the center of the circle of frames. The insets show the planets magnified many times. (Courtesy NASA/JPL)

Portrait of the Solar System
These six narrow-angle color images were made from the first ever "portrait" of the solar system taken by Voyager 1, which was more than 6.4 billion kilometers (4 billion miles) from Earth and about 32° above the ecliptic. Mercury is too close to the Sun to be seen. Mars was not detectable by the Voyager cameras due to scattered sunlight in the optics, and Pluto was not included in the mosaic because of its small size and distance from the Sun. These blown-up images, left to right and top to bottom are Venus, Earth, Jupiter, Saturn, Uranus, and Neptune. (Courtesy NASA/JPL)


The following table lists statistical information for the Sun and planets:

	Distance (AU)	Radius (Earth's)	Mass (Earth's)	Rotation (Earth's)	# Moons	Orbital Inclination	Orbital Eccentricity	Obliquity	Density (g/cm3)
Sun	0	109	332,800	25-36*	9	---	---	---	1.410
Mercury	0.39	0.38	0.05	58.8	0	7	0.2056	0.1°	5.43
Venus	0.72	0.95	0.89	244	0	3.394	0.0068	177.4°	5.25
Earth	1.0	1.00	1.00	1.00	1	0.000	0.0167	23.45°	5.52
Mars	1.5	0.53	0.11	1.029	2	1.850	0.0934	25.19°	3.95
Jupiter	5.2	11	318	0.411	16	1.308	0.0483	3.12°	1.33
Saturn	9.5	9	95	0.428	18	2.488	0.0560	26.73°	0.69
Uranus	19.2	4	17	0.748	15	0.774	0.0461	97.86°	1.29
Neptune	30.1	4	17	0.802	8	1.774	0.0097	29.56°	1.64
Pluto	39.5	0.18	0.002	0.267	1	17.15	0.2482	119.6°	2.03

* The Sun's period of rotation at the surface varies from approximately 25 days at the equator to 36 days at the poles. Deep down, below the convective zone, everything appears to rotate with a period of 27 days.

Intel was one of the pioneering Microprocessor manufacturers when it created the 4004 processor in 1971. This was followed by the 8080 processor in the late 70's, which was developed into the 8086 and 8088 processors in 1979. It was only when, in 1981 IBM selected the 8086 processor for its new Personal Computer, the IBM PC, did the Intel processor design gain its opportunity to be used widely. The Intel 8086/8088 range of processors were based upon Complex Instruction Set Computing (CISC) which allows the number of bytes per instruction to vary according to the instruction being processed. This is unlike Reduced Instruction Set Computing (RISC) which has fixed length instructions (typically set at 32 bits each). The architechture pioneered by Intel has become known as "x86" due to the early naming system where processors were called 8086, 80186 (not used in PC's), 80286, 80386, and 80486. In 1982 Intel introduced the 80286 (or 286) processor. This featured significant enhancements over the 8086/8088 line, mainly by introducing protected mode and the ability to address up to 16 megabytes of memory. The 286 processor was used in the IBM XT range. 1985 saw the introduction of the 80386 (or 386), which was the first processor to use 32 bit addressing, allowing it to utilise up to 4 Gigabytes of memory. A cut down version of the 386 known as the 386SX was introduced which had a lower memory throughput, as it could only access 16 megabytes of memory. The 386 processor was manufactured in many different versions and ran at speeds from 16 Mhz through to 40 Mhz. The 80486 processor family was introduced in 1989. It featured little enhancements over than the 386 other than the fact that it had more transistors and could run at higher clock speeds. Like its predecessor the 386, the 486 was offered in budget (486 SX, minus the math co-processor) and standard (486 DX) versions. The 486 initially ran at clock speeds of 25 MHz (SX only) and 33 MHz. As it was developed the 486 was enhanced with a clock doubled processor core (486 DX-2) allowing it to run at speeds of 50, 66 and 75 MHz, and then tripled (DX-4) which ran up to 100 MHz. 1993 saw the introduction of the Pentium processor, first at speeds of 60 and 66 MHz. This was the first Intel processor not to use the x86 naming system. This processor was enhanced with MMX instructions in January 1997 and ran up to speeds of 233 Mhz. Intel's 6th generation processor was introduced as the Pentium Pro in 1995. This ran at speeds of 166, 180 and 200 MHz. What was significant was the integration of the processors 2nd level cache memory onto the processor module itself. This processor was enhanced with MMX instructions in 1997 with its development into the Pentium II. This marked a departure for Intel as it moved away from the old socket method of mounting processors with the introduction of Slot 1. The Pentium II runs at speeds from 233 to 450 MHz. 1998 saw the development of this familiy into the Celeron and Xeon families for the budget and server/workstation markets respectively.

 

Romeo and Juliet is a tragedy written early in the career of playwright William Shakespeare about two young "star-cross'd lovers"^[1] whose deaths ultimately unite their feuding families. It was among Shakespeare's most popular plays during his lifetime and, along with Hamlet and Macbeth, is one of his most frequently performed plays. Today, the title characters are regarded as archetypal young lovers.

Romeo and Juliet belongs to a tradition of tragic romances stretching back to antiquity. Its plot is based on an Italian tale, translated into verse as The Tragical History of Romeus and Juliet by Arthur Brooke in 1562, and retold in prose in Palace of Pleasure by William Painter in 1582. Shakespeare borrowed heavily from both, but developed supporting characters, particularly Mercutio and Paris, in order to expand the plot. Believed to be written between 1591 and 1595, the play was first published in a quarto version in 1597. This text was of poor quality, and later editions corrected it, bringing it more in line with Shakespeare's original text.

Shakespeare's use of dramatic structure, especially effects such as switching between comedy and tragedy to heighten tension, his expansion of minor characters, and his use of sub-plots to embellish the story, has been praised as an early sign of his dramatic skill. The play ascribes different poetic forms to different characters, sometimes changing the form as the character develops. Romeo, for example, grows more adept at the sonnet over the course of the play.

Romeo and Juliet has been adapted numerous times for stage, film, musical and opera. During the Restoration, it was revived and heavily revised by William Davenant. David Garrick's 18th-century version also modified several scenes, removing material then considered indecent, and Georg Benda's operatic adaptation omitted much of the action and added a happy ending. Performances in the 19th century, including Charlotte Cushman's, restored the original text, and focused on greater realism. John Gielgud's 1935 version kept very close to Shakespeare's text, and used Elizabethan costumes and staging to enhance the drama. In the 20th century the play has been adapted in versions as diverse as MGM's comparatively faithful 1936 film, the 1950s stage musical West Side Story, and 1996's MTV-inspired Romeo + Juliet.

The play begins with a street brawl between Montagues and Capulets. The Prince of Verona intervenes and declares that further breach of the peace will be punishable by death. Later, Count Paris talks to Lord Capulet about marrying his daughter, but Capulet is wary of the request because Juliet is only thirteen. Capulet asks Paris to wait another two years and invites him to attend a planned Capulet ball. Lady Capulet and Juliet's nurse try to persuade Juliet to accept Paris' courtship.

Meanwhile, at the house of Montague, Benvolio talks with his cousin Romeo, Lord Montague's son, about Romeo's recent depression. Benvolio discovers that it stems from unrequited love for a girl named Rosaline, one of Lord Capulet's nieces. Persuaded by Benvolio and Mercutio, Romeo attends the ball at the Capulet house in hopes of meeting Rosaline. However, Romeo instead meets and falls in love with Juliet. After the ball, in what is now called the "balcony scene", Romeo sneaks into the Capulet courtyard and overhears Juliet on her balcony vowing her love to him in spite of her family's hatred of the Montagues. Romeo makes himself known to her and they agree to be married. With the help of Friar Laurence, who hopes to reconcile the two families through their children's union, they are secretly married the next day.

Juliet's cousin Tybalt, incensed that Romeo had sneaked into the Capulet ball, challenges him to a duel. Romeo, now considering Tybalt his kinsman, refuses to fight. Mercutio is offended by Tybalt's insolence, as well as Romeo's "vile submission",^[3] and accepts the duel on Romeo's behalf. Mercutio is fatally wounded when Romeo attempts to break up the fight. Grief-stricken and racked with guilt, Romeo confronts and slays Tybalt.

Montague argues that Romeo has justly executed Tybalt for the murder of Mercutio. The Prince, now having lost a kinsman in the warring families' feud, exiles Romeo from Verona and declares that if Romeo returns, "that hour is his last". Romeo secretly spends the night in Juliet's chamber, where they consummate their marriage. Lord Capulet, misinterpreting Juliet's grief, agrees to marry her to Count Paris and threatens to disown her when she refuses to become Paris's "joyful bride". When she then pleads for the marriage to be delayed, her mother rejects her.

Juliet visits Friar Laurence for help, and he offers her a drug that will put her into a death-like coma for "two and forty hours".^[4] The Friar promises to send a messenger to inform Romeo of the plan, so that he can rejoin her when she awakens. On the night before the wedding, she takes the drug and, when discovered apparently dead, she is laid in the family crypt.

The messenger, however, does not reach Romeo and, instead, he learns of Juliet's apparent death from his servant Balthasar. Heartbroken, Romeo buys poison from an apothecary and goes to the Capulet crypt. He encounters Paris who has come to mourn Juliet privately. Believing Romeo to be a vandal, Paris confronts him and, in the ensuing battle, Romeo kills Paris. Still believing Juliet to be dead, he drinks the poison. Juliet then awakens and, finding Romeo dead, stabs herself with his dagger. The feuding families and the Prince meet at the tomb to find all three dead. Friar Laurence recounts the story of the two "star-cross'd lovers". The families are reconciled by their children's deaths and agree to end their violent feud. The play ends with the Prince's elegy for the lovers: "For never was a story of more woe / Than this of Juliet and her Romeo.

Trunyan is another ancient village inhabited by people who call themselves the “Bali Aga” or old Bali who live in ways that are vastly different from other Balinese. The Bali Aga's temple in this village is named Puser Jagat, meaning Navel of the Universe. Its architecture is highly unusual, and stands in the protective shade of a massive banyan tree.

The Bali Aga has a strange way of burial. Instead of cremating their corpses, the Bali Aga simply places them under this banyan tree. The odor is mysteriously masked by a special arboreal fragrance emitted by the banyan tree.

The village of Trunyan is squeezed tightly between the lake and the outer crater rim of Batur, an almighty volcano in Kintamani. This is a Bali Aga village, inhabited by descendants of the original Balinese, the people who predate the arrival of the Hindu Majapahit kingdom in the 16th century. It is famous for the Pura Pancering Jagat temple, but unfortunately visitors are not allowed inside. There is also a couple of traditional Bali Aga-style dwellings, and a large banyan tree, which is said to be more than 1,100 years old. At Kuban sub-village close to Trunyan is a mysterious cemetery that is separated by the lake and accessible only by boat, there is no path along the steep walls of the crater rim.

Unlike the Balinese people, Trunyan people do not cremate or bury their dead, but just lay them out in bamboo cages to decompose, although strangely there is no stench. A macabre collection of skulls and bones lies on the stone platform and the surrounding areas. The dead bodies don't produce bad smells because of the perfumed scents from a huge Taru Menyan tree growing nearby. Taru means 'tree' and Menyan means 'nice smell'. The name of Trunyan was also derived from these two words. The women from Trunyan are prohibited from going to the cemetery when a dead body is carried there. This follows the deeply rooted belief that if a woman comes to the cemetery while a corpse is being carried there, there will be a disaster in the village, for example a landslide or a volcanic eruption. Such events have been frequent in the village's history, but whether women had anything to do with it is a matter of opinion.