Earth is the third planet from the Sun and the only astronomical object known to harbor life. According to radiometric dating and other evidence, Earth formed over 4.5 billion years ago. Earth's gravity interacts with other objects in space the Sun and the Moon, Earth's only natural satellite. Earth orbits around the Sun in a period known as an Earth sidereal year. During this time, Earth rotates about its axis about 366.256 times. Earth's axis of rotation is tilted with respect to its orbital plane; the gravitational interaction between Earth and the Moon causes tides, stabilizes Earth's orientation on its axis, slows its rotation. Earth is the densest planet in the Solar System and the largest and most massive of the four rocky planets. Earth's outer layer is divided into several rigid tectonic plates that migrate across the surface over many millions of years. About 29 % of Earth's surface is land consisting of islands; the remaining 71% is covered with water by oceans but lakes and other fresh water, which all together constitute the hydrosphere.

The majority of Earth's polar regions are covered in ice, including the Antarctic ice sheet and the sea ice of the Arctic ice pack. Earth's interior remains active with a solid iron inner core, a liquid outer core that generates Earth's magnetic field, a convecting mantle that drives plate tectonics. Within the first billion years of Earth's history, life appeared in the oceans and began to affect Earth's atmosphere and surface, leading to the proliferation of anaerobic and aerobic organisms; some geological evidence indicates. Since the combination of Earth's distance from the Sun, physical properties and geological history have allowed life to evolve and thrive. In the history of life on Earth, biodiversity has gone through long periods of expansion punctuated by mass extinctions. Over 99% of all species that lived on Earth are extinct. Estimates of the number of species on Earth today vary widely. Over 7.7 billion humans live on Earth and depend on its biosphere and natural resources for their survival.

Politically, the world has around 200 sovereign states. The modern English word Earth developed from a wide variety of Middle English forms, which derived from an Old English noun most spelled eorðe, it has cognates in every Germanic language, their proto-Germanic root has been reconstructed as *erþō. In its earliest appearances, eorðe was being used to translate the many senses of Latin terra and Greek γῆ: the ground, its soil, dry land, the human world, the surface of the world, the globe itself; as with Terra and Gaia, Earth was a personified goddess in Germanic paganism: the Angles were listed by Tacitus as among the devotees of Nerthus, Norse mythology included Jörð, a giantess given as the mother of Thor. Earth was written in lowercase, from early Middle English, its definite sense as "the globe" was expressed as the earth. By Early Modern English, many nouns were capitalized, the earth became the Earth when referenced along with other heavenly bodies. More the name is sometimes given as Earth, by analogy with the names of the other planets.

House styles now vary: Oxford spelling recognizes the lowercase form as the most common, with the capitalized form an acceptable variant. Another convention capitalizes "Earth" when appearing as a name but writes it in lowercase when preceded by the, it always appears in lowercase in colloquial expressions such as "what on earth are you doing?" The oldest material found in the Solar System is dated to 4.5672±0.0006 billion years ago. By 4.54±0.04 Bya the primordial Earth had formed. The bodies in the Solar System evolved with the Sun. In theory, a solar nebula partitions a volume out of a molecular cloud by gravitational collapse, which begins to spin and flatten into a circumstellar disk, the planets grow out of that disk with the Sun. A nebula contains gas, ice grains, dust. According to nebular theory, planetesimals formed by accretion, with the primordial Earth taking 10–20 million years to form. A subject of research is the formation of some 4.53 Bya. A leading hypothesis is that it was formed by accretion from material loosed from Earth after a Mars-sized object, named Theia, hit Earth.

In this view, the mass of Theia was 10 percent of Earth. Between 4.1 and 3.8 Bya, numerous asteroid impacts during the Late Heavy Bombardment caused significant changes to the greater surface environment of the Moon and, by inference, to that of Earth. Earth's atmosphere and oceans were formed by volcanic outgassing. Water vapor from these sources condensed into the oceans, augmented by water and ice from asteroids and comets. In this model, atmospheric "greenhouse gases" kept the oceans from freezing when the newly forming Sun had only 70% of its current luminosity. By 3.5 Bya, Earth's magnetic field was established, which helped prevent the atmosphere from being stripped away by the solar wind. A crust formed; the two models that explain land mass propose either a steady growth to the present-day forms or, more a rapid growth early in Earth history followed by a long-term steady continental area. Continents formed by plate tectonics, a process driven by the continuous

Castor oil

Castor oil is a vegetable oil pressed from castor beans. The name comes from its use as a replacement for castoreum. Castor oil is a colourless to pale yellow liquid with a distinct taste and odor, its boiling point is 313 °C and its density is 961 kg/m3. It is a triglyceride in which 90 percent of fatty acid chains are ricinoleates. Oleate and linoleates are the other significant components. Castor oil and its derivatives are used in the manufacturing of soaps, lubricants and brake fluids, dyes, inks, cold resistant plastics and polishes, nylon and perfumes. Castor oil is well known as a source of a monounsaturated, 18-carbon fatty acid. Among fatty acids, ricinoleic acid is unusual in that it has a hydroxyl functional group on the 12th carbon; this functional group causes ricinoleic acid to be more polar than most fats. The chemical reactivity of the alcohol group allows chemical derivatization, not possible with most other seed oils; because of its ricinoleic acid content, castor oil is a valuable chemical in feedstocks, commanding a higher price than other seed oils.

As an example, in July 2007, Indian castor oil sold for about US$0.90 per kilogram whereas U. S. soybean and canola oils sold for about US$0.30 per kilogram. Annually 270,000–360,000 tonnes of castor oil are produced for a variety of uses. In the food industry, castor oil is used in food additives, candy, as a mold inhibitor, in packaging. Polyoxyethylated castor oil is used in the food industries. In India and Nepal food grains are preserved by the application of castor oil, it stops rice and pulses from rotting. For example, the legume pigeon pea is available coated in oil for extended storage. Use of castor oil as a laxative is attested to in the circa 1550 BC Ebers Papyrus, was in use for several centuries prior; the United States Food and Drug Administration has categorized castor oil as "generally recognized as safe and effective" for over-the-counter use as a laxative with its major site of action the small intestine where it is digested into ricinoleic acid. Despite castor oil being used in an attempt to induce labor in pregnant women, to date there is not enough research to show whether it is effective to dilate the cervix or induce labor.

Therapeutically, modern drugs are given in a pure chemical state, so most active ingredients are combined with excipients or additives. Castor oil, or a castor oil derivative such as Kolliphor EL, is added to many modern drugs, including: Miconazole, an antifungal agent. Optive Plus and Refresh Ultra, are artificial tears to treat dry eye. Castor oil is one of the components of Vishnevsky liniment. In naturopathy castor oil has been promoted as a treatment for a variety of human health conditions, including cysts; the claim has been made. However, according to the American Cancer Society, "available scientific evidence does not support claims that castor oil on the skin cures cancer or any other disease." Castor oil has been used in cosmetic products included as a moisturizer. It has been used to enhance hair conditioning in other products and for supposed anti-dandruff properties. Castor oil is used as a bio-based polyol in the polyurethane industry; the average functionality of castor oil is 2.7, so it is used as a rigid polyol and in coatings.

One particular use is in a polyurethane concrete where a Castor Oil emulsion is reacted with an isocyanate and a Cement and Construction aggregate. This is applied thickly as a slurry, self-levelling; this base is further coated with other systems to build a resilient floor. It is not a drying oil, meaning that it has a low reactivity with air compared to oils such as linseed oil and tung oil. Dehydration of castor oil yields linoleic acids. In this process, the OH group on the ricinoleic acid along with a hydrogen from the next carbon atom are removed yielding a double bond which has oxidative cross-linking properties yielding the drying oil. Castor oil can be broken down into other chemical compounds. Transesterification followed by steam cracking gives undecylenic acid, a precursor to specialized polymer nylon 11, heptanal, a component in fragrances. Breakdown of castor oil in strong base gives 2-octanol, both a fragrance component and a specialized solvent, the dicarboxylic acid sebacic acid.

Hydrogenation of castor oil saturates the alkenes. Castor oil may be epoxidized by reacting the OH groups with Epichlorohydrin to make the triglycidyl ether of castor oil, useful in epoxy technology; this is available com

Gerry Alexander

Franz Copeland Murray Alexander OD, known as Gerry Alexander, was a Jamaican cricketer who played 25 Test matches for the West Indies. He was a wicket-keeper who had 90 dismissals in his 25 Test appearances and, though his batting average was around 30 in both Test and first class cricket, his only first-class century came in a Test on the 1960–61 tour of Australia. Alexander was the last white man to captain the West Indies cricket team, he led the West Indies against Pakistan at home in 1958, on the tour of India and Pakistan in 1958–59 and against England in 1960. He would not tolerate the indiscipline of Roy Gilchrist on the tour of India and sent him home before the team reached Pakistan, he was educated at Wolmer’s Boys' School, founded in 1729 and is one of the oldest schools in the West Indies. He attended Gonville and Caius College, Cambridge, he played for the Cambridge cricket team in both 1952 and 1953, winning a Blue in both years for appearing in the University Match against Oxford.

He won a Blue at football, went on to win an England amateur cap and an FA Amateur Cup winner’s medal in 1953 playing for Pegasus. He played cricket for Cambridgeshire in 1954 and 1955, he represented Great Britain at football in 1956 in a qualifying game versus Bulgaria on 12 May 1956 at Wembley. The match ended 3-3. Having not played a first-class match since 1953, he appeared for Jamaica in two matches against the touring Duke of Norfolk's XI in March 1957, he appeared in a trial match for the West Indies tour to England that summer, sharing a stand of 134 with Wes Hall. As a result he was chosen as wicketkeeper for the touring team, though his selection was controversial, he only appeared in the final two Tests of that series, Rohan Kanhai being preferred as a makeshift keeper for the first three. Alexander distinguished himself in neither match, scoring 0 not out, 11, 0 and 0 and not keeping well, West Indies lost both matches by an innings. After the series John Goddard, the captain, retired.

For the first time it seemed possible. However Frank Worrell declined the position because he was studying for a degree in economics at Manchester University, the other senior players Everton Weekes and Clyde Walcott were not considered suitable, thus Alexander was offered the job and, as his Telegraph obituarist writes "through patience and encouragement... succeeded in forging the array of talent in the West Indies side into a coherent and successful team."In his first series as captain, in 1958, West Indies won at home by three matches to one against Pakistan. He performed better both as batsman and keeper, including playing an important innings of 57 in the second innings of the second Test."West Indies next toured India and Pakistan. For the first time since World War II they had to manage without any of the “three Ws”, the core of their batting: Worrell and Walcott, they won three Tests against India and drew the remaining two. On the only occasion that they were in difficulties, against the leg-spin of Subhash Gupte in the second Test, Alexander scored 70 to save the day."Against North Zone in the last match of the Indian leg of the tour, Roy Gilchrist, who in earlier matches had shown a tendency to bowl beamers when angry or frustrated, unleashed a barrage of such deliveries against Swaranjit Singh, whom Alexander had known at Cambridge.

Gilchrist ignored his captain's instruction to cease this form of attack. During the lunch interval Alexander substituted Gilchrist. Subsequently Gilchrist was sent home, while the other players proceeded to Pakistan for the remainder of the tour. Alexander told Gilchrist: “You will leave by the next flight. Good afternoon.” This was the end of Gilchrist's Test career. There were suggestions. West Indies lost their first two Tests against Pakistan but won the third, Pakistan's first home defeat; the following winter, West Indies lost by one Test to nil against England, with four matches drawn, under Alexander's captaincy. He had the consolation of finishing the series with 23 victims as wicketkeeper, equalling John Waite’s world record; the West Indies lost in the second Test in Trinidad, the crowd rioted when they collapsed in their first innings. As a white man and a Jamaican, Alexander was an unpopular figure with the Trinidad crowd. Frank Worrell's return to the West Indies team for that series encouraged CLR James, the editor of The Nation, to campaign for him to replace Alexander as captain, Worrell was chosen to lead the tour to Australia the following winter.

Alexander took the decision well, was supportive of Worrell, a close friend. According to his obituarist: "The dismissed captain had taken over a side in total disarray and laid the foundations for future triumphs."He had a remarkably successful tour of Australia with the bat, scoring 60, 5, 5, 72, 0, 108, 63, 87 not out, 11 and 73 in the Tests. His century at Sydney was an important factor in enabling West Indies to win, was the only one of his first-class career, he kept wicket well. At the end of the tour he retired from cricket. After retiring as a cricketer he returned to the West Indies, where he pursued a career as a veterinary surgeon, he became Chief Veterinary Officer. In 1982 Jamaica awarded him the Order of Distinction for his contribution to sport, he died on 16 April 2011 at the age of 82 in Jamaica. His wife Barbara had died only four weeks previously. Gerry Alexander at ESPNcricinfo