Age of the Earth

The age of the Earth is estimated to be 4.54 ± 0.05 billion years. This age may represent the age of the Earth's accretion, or core formation, or of the material from which the Earth formed; this dating is based on evidence from radiometric age-dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples. Following the development of radiometric age-dating in the early 20th century, measurements of lead in uranium-rich minerals showed that some were in excess of a billion years old; the oldest such minerals analyzed to date—small crystals of zircon from the Jack Hills of Western Australia—are at least 4.404 billion years old. Calcium–aluminium-rich inclusions—the oldest known solid constituents within meteorites that are formed within the Solar System—are 4.567 billion years old, giving a lower limit for the age of the Solar System. It is hypothesised that the accretion of Earth began soon after the formation of the calcium-aluminium-rich inclusions and the meteorites.

Because the time this accretion process took is not yet known, predictions from different accretion models range from a few million up to about 100 million years, the difference between the age of Earth and of the oldest rocks is difficult to determine. It is difficult to determine the exact age of the oldest rocks on Earth, exposed at the surface, as they are aggregates of minerals of different ages. Studies of strata - the layering of rocks and earth - gave naturalists an appreciation that Earth may have been through many changes during its existence; these layers contained fossilized remains of unknown creatures, leading some to interpret a progression of organisms from layer to layer. Nicolas Steno in the 17th century was one of the first naturalists to appreciate the connection between fossil remains and strata, his observations led him to formulate important stratigraphic concepts. In the 1790s, William Smith hypothesized that if two layers of rock at differing locations contained similar fossils it was plausible that the layers were the same age.

William Smith's nephew and student, John Phillips calculated by such means that Earth was about 96 million years old. In the mid-18th century, the naturalist Mikhail Lomonosov suggested that Earth had been created separately from, several hundred thousand years before, the rest of the universe. Lomonosov's ideas were speculative. In 1779 the Comte du Buffon tried to obtain a value for the age of Earth using an experiment: He created a small globe that resembled Earth in composition and measured its rate of cooling; this led him to estimate. Other naturalists used these hypotheses to construct a history of Earth, though their timelines were inexact as they did not know how long it took to lay down stratigraphic layers. In 1830, geologist Charles Lyell, developing ideas found in James Hutton's works, popularized the concept that the features of Earth were in perpetual change and reforming continuously, the rate of this change was constant; this was a challenge to the traditional view, which saw the history of Earth as dominated by intermittent catastrophes.

Many naturalists were influenced by Lyell to become "uniformitarians" who believed that changes were constant and uniform. In 1862, the physicist William Thomson, 1st Baron Kelvin published calculations that fixed the age of Earth at between 20 million and 400 million years, he assumed that Earth had formed as a molten object, determined the amount of time it would take for the near-surface temperature gradient to decrease to its present value. His calculations did not account for heat produced via radioactive decay or, more convection inside the Earth, which allows the temperature in the upper mantle to remain high much longer, maintaining a high thermal gradient in the crust much longer. More constraining were Kelvin's estimates of the age of the Sun, which were based on estimates of its thermal output and a theory that the Sun obtains its energy from gravitational collapse. Geologists such as Charles Lyell had trouble accepting such a short age for Earth. For biologists 100 million years seemed much too short to be plausible.

In Darwin's theory of evolution, the process of random heritable variation with cumulative selection requires great durations of time. According to modern biology, the total evolutionary history from the beginning of life to today has taken place since 3.5 to 3.8 billion years ago, the amount of time which passed since the last universal ancestor of all living organisms as shown by geological dating. In a lecture in 1869, Darwin's great advocate, Thomas H. Huxley, attacked Thomson's calculations, suggesting they appeared precise in themselves but were based on faulty assumptions; the physicist Hermann von Helmholtz and astronomer Simon Newcomb contributed their own calculations of 22 and 18 million years to the debate: they independently calculated the amount of time it would take for the Sun to condense down to its current diameter and brightness from the nebula of gas and dust from which it was born. Their values were consistent with Thomson's calculations. However, they assumed; the process of solar nuclear fusion was not yet known to science.

In 1895 John Perry challenged Kelvin's figure on the basis of his assumptions on conductivity, Oliver Heaviside entered the dialogue, considering it "a vehicle to display the ability of his operator method to solve problems of astonishi

Trevor Manuel

Trevor Andrew Manuel is a South African politician who served in the government of South Africa as Minister of Finance from 1996 to 2009, during the presidencies of Nelson Mandela, Thabo Mbeki and Kgalema Motlanthe, subsequently as Minister in the Presidency for the National Planning Commission from 2009 to 2014 under former President Jacob Zuma. Trevor Manuel was born in Kensington, during the apartheid era and was classified as a Cape Coloured, his mother, Philma van Söhnen, was a garment factory worker, his father, Abraham James Manuel, was a draughtsman. According to Manuel's "family legend", his great-grandfather was a Portuguese immigrant. Manuel was educated in the city, he matriculated from the Harold Cressy High School in 1973 and studied Civil and Structural Engineering, during his detention, law. Manuel entered public life in 1981 as the General Secretary of the Cape Areas Housing Action Committee, after which he became a National Executive member of the United Democratic Front. In September 1985 Manuel was detained and banned until 31 August 1990.

However, Manuel's ban was lifted on 25 March 1986 after it was ruled that it was not in line with the provisions of the Internal Security Act. On 15 August 1986 Manuel was again detained under the emergency regulations for two years until July 1988, he was released from detention under severe restrictions but promptly detained again in September 1988, this time until February 1989. His release came with stringent restriction orders. After the unbanning of the African National Congress, Manuel was appointed as deputy co-ordinator in the Western Cape Province. At the ANC's first regional conference in 1990 Manuel was elected publicity secretary. At the ANC's 1991 national conference Manuel was elected to the National Executive Committee. In 1992 Manuel became head of the ANC's Department of Economic Planning. Manuel was elected as an ANC Member of Parliament in 1994 and was appointed by President Nelson Mandela as Minister of Trade and Industry; the World Economic Forum selected Manuel as a "Global Leader for Tomorrow" in 1994, he has received numerous international awards and recognition for his accomplishments.

South Africa reported its first budget surplus in 2007. A combination of increased prosperity, high commodity prices and a wider tax base were credited with the surge of revenue. Manuel increased spending for education and sanitation. In the 2002 election to the ANC's National Executive Committee, Manuel placed first. At the ANC conference in Polokwane in December 2007, he was again elected to the National Executive Committee, this time in 57th place with 1,590 votes. In April 2008 Manuel was announced chancellor of the Cape Peninsula University of Technology. In September 2008, the International Monetary Fund commissioned a "Committee on IMF Governance Reform", to be chaired by Manuel; this report was submitted in March 2009. According to papers seen by The Citizen, Manuel approved a contract on modernisation at the SA Revenue Service, worth R100 million standing at R1 billion, without following due processes. In August 2017, HAWK asked Trevour Manuel and Pravin Gordhan to provide an affidavit on setting up SARS intelligence unit to spy on politicians.

On 23 September 2008, Trevor Manuel resigned as Finance Minister along with a number of other cabinet members after the resignation of President Thabo Mbeki, unsettling the financial market, but it was subsequently announced that he would be willing to continue to serve under the next president. Manuel explained the resignation as a principled gesture, he expressed surprise at the market's reaction, he was retained in his post in the cabinet of Mbeki's successor, Kgalema Motlanthe, announced on 25 September. On 2 March 2011, Manuel published an open letter to Jimmy Manyi, the spokesperson for the South African government, in which he accused him of racism and compared him to Hendrik Verwoerd; this letter was precipitated by the remarks that Manyi made about a change in the labour laws he had proposed in his previous position of Director-General of Labour. These changes affect the racial quota that employers in South Africa are to apply to their work force, they needed to reflect the ethnic composition of the local community.

Such a change would have severe consequences for the Coloured community of the Western Cape as well as for the Indian community of KwaZulu-Natal. For the former only 10 % of jobs would be available in regions. Manyi claimed that there was a "surplus" of Coloureds in the West-Cape and that this'problem' should be solved by making the members of this community spread over other provinces—a solution similar to that of relocation under apartheid. Manuel's sharp reaction to Manyi's remarks provoked an sharp response from Paul Ngobeni, a prominent backer of Jacob Zuma and John Hlophe. Trevor Manuel married Lynne Matthews in 1985; the couple had three sons Govan and Jaime. The couple separated in 2001 and divorced in 2007. Manuel married Maria Ramos on 27 December 2008 at the age of 52; the Hawks indicted Manuel and his one-time deputy, Jabu Moleketi, to provide affidavits on the creation of a special investigative unit in the South African Revenue Service that spied on politicians. The National Prosecuting Authority has been probing the unit in an investigation in which former finance minister Pravin Gordhan was summoned.

List of people subject to banning orders under apartheid

Stella Maris College, Chennai

Stella Maris College is a Roman Catholic Latin Rite institution of higher education for women in Chennai, India. It is an autonomous college affiliated to the University of Madras and is residential; the college, under the direction of the Society of the Franciscan Missionaries of Mary, is a minority institution that provides university education in a Christian atmosphere for deserving students those belonging to the Catholic community. It has five hostels - Snehalaya, Klemens, St. Josephs and Nava Nirmana. Beginning in a small one-storey building on 15 August 1947, with an enrollment of 32 students, the college has at present over 5,500 students housed in large buildings on the campus of "The Cloisters", Cathedral Road, Chennai; the college has 19 undergraduate and 12 postgraduate programmes. Research programmes such as M. Phil, PhD, postgraduate diploma courses are part of the academic curriculum; the college is under the management of the Institute of the Franciscan Missionaries of Mary. It was founded on 15 August 1947 with an enrollment of 32 students in the intermediate class.

Stella Maris was granted permanent recognition in 1951. The college has the unique credit of having initiated bachelor's degrees in Western Music and History of Fine Arts, as well as master's degrees in Social Work and Indian Music, at the University of Madras. Additionally, it was the first women's college in Madras to offer M. A. degree courses in English and Fine Arts. In 1960, the college moved from Santhome to a more spacious campus, "The Cloisters", Cathedral Road, Chennai; the following few decades saw tremendous growth and development in the college with several firsts and distinctions. The college was one of the few chosen to start the pilot project of the National Service Scheme in 1968. A spacious library was erected on the occasion of the Silver Jubilee of the college in 1972 and occupies a place of pride on the campus as well as in Chennai. From 1978 onwards there was a shift in the admission policy, keeping in mind the thrust of the college towards social justice. Conscious of the growing need for academic freedom, the college launched into autonomy in 1987.

Com. and Mathematics. On the occasion of the Golden Jubilee, the St. Clare's Centre- a four-story building that houses the administrative offices, an audio-visual room, computer laboratories, several classrooms- was erected. With ten years of experiential learning processes behind it, the college restructured its system of education by introducing a credit-based system in 1997, offering many new academic programmes that encourage interdisciplinary associations. Coaching for the Civil Services exams was launched in November 2009; the college conducts coaching classes for both faculty and students who are preparing to appear for the NET and SLET exams. Advanced Zoology and Biotechnology Bioinformatics Biotechnology Business Administration Chemistry Commerce Computer Applications Economics English History & Tourism Information Technology International Studies Languages Mathematics Physics Plant Biology and Plant Biotechnology Psychology Public Relations Religion and Value Education Social Work Sociology Visual Arts Vocational Programmes: Sustainable Energy Management Food Processing and Quality Control Diploma Courses:Computer Science Medical Laboratory Technology As of 2014, the college has undertaken around twelve environmental initiatives including light-emitting diode cluster lights, solar-powered streetlights, source segregation, vermi-composting, waste water recycling plant.

In January 2014, the college opted for green energy with the installation of a 50-kilo watt roof-top solar power plant on its campus. The plant, installed by Omega Natural Polarity Private Limited at a cost of ₹ 5 million, has 200 solar panels and caters to six percent of the total power requirement on the campus, powering lights and fans in the college. Samantha Akkineni, actress G. Thilakavathi IPS, police officer and Tamil writer Sheela Murthy, U. S. immigration attorney Malini Parthasarathy, The Hindu Anju Bhargava, political operative Preetha Reddy, managing director of Apollo Hospitals Rama Ravi, Carnatic vocalist Savitha Sastry, dancer Geeta Menon, educator. Brindha sivakumar, daughter of Actor sivakumar and sister of Actor suriya and Actor karthi Jayalalitha, Actress