Canopus, or Alpha Carinae in the Bayer designation system, is the brightest star in its constellation (Carina) and the brightest star in the southern night sky.
Canopus is quite unusual, because its distance from Earth was not known until the 1990s. Before the launching of the Hipparcos satellite telescope, distance estimates for the star varied widely, from 96 light years to 1200 light years. Hipparcos established Canopus as lying 310 light years (96 parsecs) from our solar system.
The difficulty in measuring Canopus' distance stemmed from its being a "less luminous supergiant". Such stars are rare and poorly understood. They are stars that can be either in the process of evolving to or away from red giant status. This in turn made it difficult to know how intrinsically bright Canopus is, and therefore how far away it might be. Direct measurement was the only way to solve the problem. Canopus is too far away for Earth-based parallax observations to be made, so the star's distance was not known with certainty until the early 1990s.
Canopus is 13,600 times more luminous than the Sun and the most intrinsically bright star within about 700 light years. In fact, from 1 astronomical unit, Canopus would have an apparent magnitude of -37. Canopus appears less bright than Sirius in our sky only because Sirius is much closer to the Earth (8.6 light years).
The surface temperature of Canopus is 7350 ± 30 K. Its diameter has been measured at 0.6 astronomical units (the measured angular diameter being 0.006 arcseconds), 65 times that of the Sun. If it were placed at the centre of the solar system, it would extend three-quarters of the way to Mercury. An Earth-like planet would have to lie three times the distance of Pluto for its star to appear the same size in the sky as our own sun. Canopus is a strong source of X-rays, which are probably produced by its corona, magnetically heated to around 15 million K.
Canopus is part of the Scorpius-Centaurus Association, a group of stars which share similar origins.
Bayer designation
The Bayer designation for stars uses to assign names to stars. For example:
It usually starts with the letter alpha (α) assigned to the brightest star in the constellation, then going down the to assign letters for other stars (beta, gamma, delta, etc.) in order of decreasing brightness.
Demographics of Pakistan
The Demographics of Pakistan are a study of the population and the people. It is estimated that Pakistan's population was over 170,000,000 in mid 2008. Pakistan had an estimated population of 169,300,000 as of July 2007. Between 1951-1998, the number of people in Pakistan's cities and towns (known as the urban population) increased sevenfold. And by the next decade the population is expected to exceed 176 million. In the past, the country's population had a quite high growth rate. Dramatic social changes have led to rapid urbanisation and the emergence of megacities. Between 1990-2003, Pakistan sustained its historical lead as the most urbanised nation in South Asia, with city dwellers making up 34% of its population.
Pakistan has a multicultural and multi-ethnic society and has one of the largest refugee populations in the world as well as a young population.
Pakistan's next national census will take place in 2008.
The majority of southern Pakistan's population lives along the Indus River. In the northern half, most of the population lives about an arc formed by the cities of Faisalabad, Lahore, Rawalpindi, Islamabad, Gujranwala, Sialkot, Nowshera, Swabi, Mardan and Peshawar.
Fahrenheit (disambiguation)
Fahrenheit may refer to:
Culture of Iran
The culture of Iran includes the art, language, cinema and music of the country. The culture of Iran has been influenced by many different things, by religion and by its ancient history. The nation has different ethnic groups including Persians, Turks and Kurds.
Apollo 17
Apollo 17 was the last flight to send people to the moon. It was done by NASA, the American space group.
It went up to space on December 7, 1972, carrying three astronauts: Eugene Cernan, Harrison Schmitt and Ronald Evans. On December 11, 1972, Cernan and Schmitt became the last humans to land on the moon, while Evans stayed in orbit around the Moon.
About 500,000 people viewed the flight of Apollo 17. A Saturn V rocket took flight from the Kennedy Space Center in America.
About two hours after leaving Earth the bit with the people in it went away from the main rocket. The bit with the people in it had two parts, the Apollo Command Module called "America" and the Apollo Lunar Module called "Challenger". "America" was the moon control space ship and "Eagle" was the moon-landing space ship. 3 days later the team entered Lunar Orbit (orbit around the moon). A day later the "Challenger" went away from "America". The "Challenger" landed safely on the moon with Eugene Cernan and Harrison Schmitt inside.
Cultural geography
Cultural Geography is the study of cultures, customs, foods, clothing, music, architecture, traditions, religions and languages of the world - and how and why these cultures are spread across the world.
An example would be the Arab World, there are many nations inhabited by Arabic people, from Morocco in the north-west of Africa and lies near to Spain, to Syria which borders Turkey - and Yemen which is near to Ethiopia.
Arab world
The Arab world (; pronounced: al-`alam al-`arabi) are the Arabic language-speaking countries stretching from the Atlantic Ocean in the west to the Arabian Sea in the east, and from the Mediterranean Sea in the north to the Horn of Africa and the Indian Ocean in the southeast. It consists of 24 countries and territories with a combined population of some 325 million people spanning at least 2 billion acres across two continents.
Horn of Africa
The Horn of Africa (alternatively Northeast Africa, and sometimes Somali Peninsula) is a peninsula in East Africa that protrudes into the Somali Sea and Guardafui Channel, and lies along the southern side of the Gulf of Aden.
The biggest ethnic group which lives in the Horn of Africa are the Cushites. Cushites include people like Afars, Oromos, and Sidama. Some people said that its a good idea for Cushites to help each other with making money and politics. This aim is sometimes called "Pan-Hornism".
There are four countries in the Horn of Africa. They are Eritrea, Ethiopia, Somalia and Djibouti. The northernmost areas of the Horn are Ras Kasar in the west, settled by the Rashaida tribe, and Alula in the east, settled by Dishiishe. The easternmost area is Ras Hafun, settled by Leelkase, and the southernmost in Ras Kamboni, settled by Dhulbahante.
The Horn of Africa became famous for taking longer to be colonized than other African countries. Those countries which fought back were Ethiopia, led by Menelik II, and the Daraawiish State, led by Ismail Mire. Eritrea was part of Ethiopia, but fought the Eritrean War of Independence from 1961 to 1991.
Horn of Africa can also mean the greater region containing the countries of Eritrea, Djibouti, Ethiopia and Somalia. The greater region covers about 2,000,000 km² (or 772,200 square miles) and is inhabited by about 94.2 million people (Ethiopia: 79 million, Somalia: 10 million, Eritrea: 4.5 million, and Djibouti: 0.7 million).
East Africa
East Africa is the most eastern region of the African continent. There are different ways to describe the area East Africa covers - it can be defined by geography or countries. It has some of the earliest found fossils of humans.
Gulf of Aden
The Gulf of Aden (, pronounced "Khalyj 'Adan"; ) is a gulf in the Indian Ocean. To its south is the Guardafui Channel, the Somali Sea and Somalia. To its north is Yemen. In the northwest, it connects with the Red Sea through the Bab el Mandeb strait. In the southwest, it connects with the Somali Sea through the Guardafui Channel.
Battle of Miani