adityasasidhar/Wikipedia_Cleaned huggingface dataset:
Today, almost 90% of all brass alloys are recycled. Brass is not ferromagnetic. Brass scrap is collected and transported to the foundry. In the foundry, it is melted and recast into billets. The billets are heated and stretched into the form and size that is wanted.
Different varieties or forms of alloys can be made from the same constituent materials (substances from which the alloy is formed). These different forms or varieties can be formed by using different amounts of the constituents.
"Raw" material is materials such as ores which we can clean and mix with other materials to make another material like steel, for example. Cotton is a raw material used to make textiles, which are used to make clothes. Material is not matter, though. Matter is everything in existence. Material is used for things that have use. Refined materials are materials that have been refined, like metal, reduced or converted into better, more useful materials like clothes and tools. Refined materials are usually mixes of other materials, like glue or steel.
The brain is the part of the body which lets living beings think. It does some bodily functions, such as telling the rest of the body what to do.
It gets input from sense organs, and changes behavior in response to this information. In humans, the brain also controls our use of language, and is capable of abstract thought. The brain is the main control centre of the whole body. The brain is made up of special cells called nerves, which are connected with each other and with other nerves in our body.
In all animals, the brain is protected in some way. In ourselves, and all vertebrates, it is protected by the bones of the skull. In woodpeckers, the brain is protected by the tongue, which wraps around the brain.
The brain does the thinking, learning, and feeling for the body. For humans, it is the source of consciousness. The brain also controls basic autonomic body actions, like breathing, digestion, heartbeat, that happen automatically. These activities, and much else, are governed by unconscious functions of the brain and nervous system. All the information about the world gathered by our senses is sent through nerves into the brain, allowing us to see, hear, smell, taste, and feel things. The brain processes this information, and we experience it as pictures, sounds, and so on. The brain also uses nerves to tell the body what to do, for example by telling muscles to move or our heart to beat faster.
In mammals, the brain is made of three main parts: the cerebrum, the cerebellum, and the brainstem. The surface of the cerebrum is the cerebral cortex, which all vertebrates have. Mammals also have an extra layer, the neocortex. This is the key to the behaviour which is typical of mammals, especially humans.
The cortex has sensory, motor, and association areas. The sensory areas are the areas that get and process information from the senses. The motor areas control voluntary movements, especially fine movements performed by the hand. The right half of the motor area controls the left side of the body, and vice versa. Association areas produce a meaningful experience of the world and supports abstract thinking and language. This enables us to interact effectively. Most connections are from one area of the cortex to another, rather than to subcortical areas; The figure may be as high as 99%.
The thalamus puts together the input from most of the senses. It is the place in the brain which makes the "picture" we have of the world outside us. The thalamus sits centrally under the cerebral cortex.
The cerebellum coordinates muscles so they work together. It is also the centre of keeping position and balance, and motor skills. It is one of the most ancient parts of the brain and sits at the back underneath the cerebral cortex.
The brain stem is at the back of the brain (actually underneath it in humans). It joins the rest of the brain with the spinal cord. It has lots of different parts that control different jobs in the body: for instance, the brain stem controls breathing, heartbeat, sneezing, eye blinking, and swallowing. Body temperature and hunger are also controlled by parts of the brain stem. Roughly speaking, it deals with the more automated aspects of nervous function.
The volume of the human brain (relative to the size of the whole body) is very large, compared to that of most other animals. The human brain also has a very large surface (called cortex) for its size, which is possible because it is very wrinkled. If the human cortex were flattened, it would be close to a square meter in area. Some other animals also have very wrinkled brains, such as dolphins and elephants. Here is a rule of thumb: the larger an animal is, the larger its brain will be. Even allowing for that, the human brain, and in particular the neocortex, is very large. We know it increased in size "four-fold" over the last several million years of evolution. There are ideas about why this happened, but no-one is quite sure. Most theories suggest complex social activity and the evolution of language would make a larger brain advantageous. As an additional note, Einstein's brain weighed only 1,230 grams, which is less than the average adult male brain (about 1,400 grams). The detailed organisation of a brain obviously matters, but in ways which are not understood at present.
Neurons have a cell body ("soma" or "cyton"), dendrites and an axon. Dendrites and axons are nerve fibers. There are about 86 billion neurons in the human brain. Almost all brain cells are neurons. The human brain has about 16 billion neurons in the cerebral cortex. The neurons are supported by glial cells and astrocytes.
There are three classes of neurons: motor neurons, sensory neurons and inter neurons.
Mature neurons never divide: that is the general rule. They do not undergo cell division. In most cases, neurons are generated by special types of stem cells. A type of glial cell, called astrocytes, have also been seen to turn into neurons. In humans, neurogenesis (the origin of new nerve cells) largely ceases during adulthood but in two brain areas, the hippocampus and the olfactory bulb, there is strong evidence for substantial numbers of new neurons..
Many ancient civilizations began in the Fertile Crescent in the Middle East. These were Sumer, Babylonia and Assyria in the area called Mesopotamia. The Abrahamic religions that believe in one God also started in the Middle East. (Judaism and Christianity began in ancient Palestine and Islam began in Arabia.) Today, the Middle East is the homeland of Arabs, Turks, Persians, Kurds, and Jews, among many other ethnic groups. Islam is the most common religion in the Middle East. Islam came to most of the Middle East's lands in the 7th century AD, during the first Muslim conquests of the Sasanian Empire and parts of the Byzantine Empire.
A point is a position in space which has no size, but which does have position.
A line is the path of one point that is moving. A line is a type of geometric figure. A line has length, but no width. A line is made up of an endless number of points.
A line can be straight or curved. In geometry, the word "line" means a "straight line". A straight line is the shortest distance between two points. A straight line is traced by a point moving in a direction that does not change.
A "curved line" is sometimes called a curve. The edge of a circle is not straight. It is an example of a curve.
A "line segment" is part of a line. Here are examples of straight line segments:
Lines can get their names from any two points on the line. For example, if a line contains two different points, named formula_1 and formula_2, then the line can be called either formula_3, or formula_4.
Sometimes, lines are named with just one symbol. A letter such as formula_5 might be used.
Some vegetables which are botanically fruits (such as tomatoes) are considered to be vegetables in the culinary (eating) sense. This is why they appear in this article. For sources, see individual pages. See also List of fruits.
The following is a small list of stars. On this list, stars should be placed by their English wiki title, unless a common name is clearly more used.
Technically, there was never a scientific definition of the term "planet" before 2006. When the Greeks observed the sky thousands of years ago, they discovered objects that acted differently than stars. These points of light seemed to wander around the sky throughout the year. The term "planet" derives from the Greek word "planets" - wanderer.
This is list of farthest galaxy from Milky Way. Remember, the farther away from a galaxy, the greater the redshift of galaxy. Redshift is when objects appear in a red color because they move away from us.
This list of the nearest galaxies to Earth is ordered by increasing distance. Many of the distances are only estimates, and some may be incorrect by 50% or more. The distance ranking in this list should be seen only as a guess. Distances are given in light years (ly).
The following is a list of main sequence stars with confirmed extrasolar planets. Note that the masses of the planets are lower bounds only. If a planet is detected by the spectral line displacement method referred to above, no information is gained about the inclination of the planet's plane of orbit around its star, and a value for this is needed to calculate the mass. It has become customary to arbitrarily assume that the plane is exactly lined up with the line of sight from Earth (this produces the lowest possible mass consistent with the spectral line measurements).
The following is a list of water sports, divided by category. This list is not complete. Some of the sports include only one part
The list of tunnels is a link page for any road tunnel, railway tunnel, or waterway tunnel anywhere in the world.
A chemical can donate a proton if the hydrogen atom is attached to an electronegative atom like oxygen, nitrogen, or chlorine. Some acids are strong and others are weak. The weak acids hold on to some of their protons, while the strong acids let go of all of them. All acids will release hydrogen ions into solutions. The amount of ions that get released per molecule will determine if the acid is weak or strong. Weak acids are acids that partially release the hydrogen atoms that are attached. These acids, then, may lower pH by dissociation of hydrogen ions, but not completely. Weak acids generally have a pH value of 4-6 while strong acids have a pH value of 1 to 3.
Acids and bases typically exist together in equilibrium. This means that within a sample of an acid, some molecules will give up their protons and others will accept them. Even water is a mixture of an acidic ion, HO (called a hydronium ion) and a basic ion, OH (called a hydroxide ion). When acids are diluted (mixed in water) they release H+ ions. These H ions cannot exist independently, so they combine with water to form Hydronium ion. A hydronium ion will give up its proton to a hydroxide ion, forming two molecules of HO, which is neutral. This reaction happens continuously in a sample of water, but overall the sample is neutral because there are equal amounts of hydronium and hydroxide in the sample. For most reactions, however, the acids and bases are not present in equal amounts, and this imbalance is what allows a chemical reaction to occur.
A mental illness is an illness of the mind. The term includes psychiatric disorder, psychological disorder, mental disease, mental breakdown, nervous breakdown, mental health conditions. People with a mental illness may behave in strange ways or have strange thoughts. Mental illnesses can affect the day-to-day functioning of a person.
The Qur'an () is the central holy book of Islam. The Qur'an is considered by Muslims to be "The Word of Allah (God)". This book is believed to have been revealed to the prophet Muhammad. Some Muslims call it the "Final Testament".
For Muslims, the Qur'an is Allah's last revelation, the last in a chain of many revelations such as the "Tawrat" (Torah), the "Zabur" (Psalms), the "Injeel" (Gospel), the "Scrolls of Abraham", and the "Scrolls of Moses". It has been written and read only in Arabic for more than 1,400 years. But, because many Muslims around the world do not understand Arabic, the meaning of the Qur'an is also given in other languages, so that readers can understand better what the Arabic words in the Qur'an mean. These books are like dictionaries to the Qur'an - they are not read as part of the religion of Islam, to replace the Arabic Qur'an. Muslims believe that these translations are not the true Qur'an; only the Arabic copy is the true Qur'an.
For most self-identified Muslims, the Qur'an is used with the hadith to interpret Sharia law (Islamic holy law). It is by far the most important and authoritative document, however, and supersedes hadiths and all earlier revelations, such as the Torah and the Bible. Saudi Arabia holds that the Qur'an is the country's constitution, although it is supplemented by more recent documents in modern Arabic.
For Shi'a Muslims, the Qur'an is used together with interpretations by special imams, especially such being a descendant from Muhammad's family, the "Ahl al-Bayt". Others use the Islamic methodology of (), which refers to interpreting the Qur'an with/through the Bible. This approach adopts canonical Arabic versions of the Bible, including the Tawrat and the Injil, both to illuminate and to add exegetical depth to the reading of the Qur'an. Notable Muslim (commentators) of the Bible and Qur'an who weaved biblical texts together with Qur'anic ones include Abu al-Hakam Abd al-Salam bin al-Isbili of Al-Andalus and Ibrahim bin Umar bin Hasan al-Biqa'i.
The Qur'an was not written all together in book-form while Muhammad was alive; it was kept by oral communication and brief written records. The prophet did not know how to read nor write, but according to Muslims, the prophet's cousin Ali ibn abi Talib, among others, used to write the texts on something when Muhammad was alive. After prophet Muhammad died, Omar ibn Khattab, one of the khulafa u rashidan, compiled the quran into a single book.
The verses of the Qur'an speak about many different topics. For example, the verses of chapter 80 (Abasa) speak about the evils of ableism, also called able-bodyism or ablecentrism. Or verse 2:15 speaks about the evils of being two-faced.
Who believe! fulfil (all) obligations. Lawful unto you (for food) are all four-footed animals. Dead meat, blood, pig, any food which has been blessed by a (false) god other than Allah; an animal whose death resulted from strangulation, bludgeoning, arrows, falling, or bloodloss; an animal which was partly consumed by a wild animal or an animal which is sacrificed on a stone altar are forbidden. However, if faced with starvation, exceptions are allowed.
Radiocarbon dating showed with a probability of more than 95%, the parchment was from between 568 and 645 AD. So the manuscript is at least 1,370 years old. It is the earliest, or among the earliest, in existence.
The fragments are written in ink on sheep or goat skin. They are mounted on a modern paper to help preserve them. They are going on display at the Barber Institute in Birmingham in October 2015.
Sir Anthony Charles Lynton "Tony" Blair (born 6 May 1953) is a British politician who served as Prime Minister of the United Kingdom from 1997 to 2007. He was Leader of the Labour Party from 1994 to 2007 and Member of Parliament (MP) for Sedgefield from 1983 to 2007. On the day he stood down as Prime Minister and MP, he was made official Envoy of the Quartet on the Middle East on behalf of the United Nations, the European Union, the United States and Russia.
An accident is when something goes wrong when it is not meant to. Physical accidents are things like collisions, injuries, and falling. Non-physical accidents are things like telling someone a secret without meaning to, forgetting something important, or deleting an important computer file.
Many things are sold to treat acne, the most popular being .Benzoyl peroxide:
Although acne appears most often in teenagers, it also appears first in people in their 20s and 30s. People of all ages get acne.
This may be the most common myth, which is not true. Washing your face twice a day can be effective and beneficial, but too much can dry out your skin, which can lead to other skin problems.
There is no proven link between chocolate, pizza, potato chips, french fries, cheeseburgers, etc., and acne outbreaks. Recent research has indicated a link between acne and non-organic dairy products.
Dinosaurs are a group of Archosaur reptiles of the clade Dinosauria. Dinosaurs are related to birds and crocodiles. They were the most powerful land animals of the Mesozoic era. Over 500 different genera of dinosaurs are known. Fossils of dinosaurs have been found on every continent.
Dinosaurs began in the Upper Triassic, about 230 million years ago (mya). The earliest date of a dinosaur fossil is that of "Eoraptor" and "Herrerasaurus" from Argentina, and "Saturnalia" from Brazil, 237 to 228 mya.
By the early Jurassic they were the top land vertebrates, and dominated most environments on land. They continued until the K/T extinction event 66 million years ago.
From the fossil record, it is known that birds are living feathered dinosaurs. They evolved from earlier theropods during the later Jurassic. They were the only line of dinosaurs to survive to the present day.
Dinosaurs had adaptations that helped make them successful. The first known dinosaurs were small predators that walked on two legs. All their descendants had an upright posture, with the legs underneath the body. This transformed their whole life-style. There were other features. Most of the smaller dinosaurs had feathers, and were probably warm-blooded. This would make them active, with a higher metabolism than modern reptiles. Social interaction, with living in herds and co-operation, seems certain for some types. The existence of communal egg-laying sites is best understood if the adults travelled in herds, as herbivores do today.
The first fossils were recognised as dinosaurs in the early 19th century. Some of their bones were found much earlier, but were not understood. William Buckland, Gideon Mantell and Richard Owen saw these bones were a special group of animals. Georges Cuvier was also important in explaining what dinosaurs were. Dinosaurs are now major attractions at museums around the world. They have become part of popular culture. There have been best-sellng books and movies. New discoveries are reported in the media.
Dinosaurs are so varied that it is not easy to find what they all share. A reasonable list would include many features of the skeleton which are not familiar to the general reader.
Dinosaurs were, at the start, small and bipedal: they walked on their hind legs. They laid eggs in nests, and included both carnivores and herbivores. We now know that birds are their living descendents, and more about that later.
Changes in the basic set-up of dinosaurs happened because of adaptations to different lifestyles. From the start of their fossil record, there were both herbivores and carnivores.
Dinosaurs were a varied group of animals. Adaptive radiation happened. This let them live in many ecological niches. Paleontologists have identified over 500 different genera and 1,000 species of non-avian dinosaurs. Their descendants, the birds, number 9,000 living species, and are the most diverse group of land vertebrates.
The largest dinosaurs were herbivores (plant-eaters), such as "Apatosaurus" and "Brachiosaurus". They were the largest animals to ever walk on dry land. Other plant-eaters, such as Iguanodon, had special weapons to help them fight off the meat-eaters. For example, "Triceratops" had three horns on its head shield, "Ankylosaurus" was covered in boney plates, and "Stegosaurus" had spikes on its tail.
The carnivores were bipedal (walked on their back legs), though not as we do. Their body was more towards the horizontal, balanced at the back by their tail. Some were very large, like "Tyrannosaurus", "Allosaurus" and "Spinosaurus", but some were small, like "Compsognathus". It was the smaller sized meat-eaters that may have evolved into birds. The first fossil bird, "Archaeopteryx", had a skeleton which looked much like that of the dinosaur "Compsognathus", as T.H. Huxley commented.
Despite their great success over a long period, there were life-styles which the dinosaurs never evolved. None ever evolved to live entirely in water, as many mammals do, though "Spinosaurus" was semi-aquatic. They never entirely dominated the small terrestrial niche. All through the Mesozoic most small vertebrates were mammals and lizards. We have much to learn still about the smaller fauna of the Mesozoic.
The extinctions at the end of the Cretaceous were caused by a catastrophic event: a massive meteorite hit the Earth (the Chicxulub impact). We now know where it hit: in the Yucantan peninsula in what is now Mexico.
Several other impact craters, and massive volcanic activity in the Deccan Traps in India, have been dated to about the time of the extinction event. These geological events may have reduced sunlight and hindered photosynthesis, leading to a massive disruption in Earth's ecology.
Did any terrestrial dinosaurs survive the great extinction event? Yes they did, because we now know that birds are descended from dinosaurs. But dinosaurs as generally understood were eliminated. Several fossils have been found in the Hell Creek Formation about 40,000 years later than the K/T extinction event. Many scientists dismiss the "Paleocene dinosaurs" as re-worked, that is, washed out of their original places and then re-buried in much later sediments. An associated skeleton (e.g. more than one bone from the same individual) found above the K/T boundary would be convincing, but no such finds have been reported.
"Jurassic Park" in 1990 started a new phase in dinosaur popular culture.
The Stone Age was a prehistoric time when people made tools from stone such as flint. It began when people created the first stone tools about 3.3 million years ago. About 99% of human history happened during the Stone Age. It lasted for about 3.4 million years, and ended between 4,000 BC and 2,000 BC and started in 15000 BC.
Stone Age people also made tools out of wood and bone. However, these materials do not last as long as stone. For this reason, most of the Stone Age tools archaeologists have found are made of stone.
Archaeologists divide the Stone Age into three sections: Palaeolithic ("old stone"), Mesolithic ("middle stone"), and Neolithic ("new stone"). During the Neolithic period, people invented farming and pottery, and started to care for animals like cows and pigs.
Sometime between 3000 BC and 2000 BC, people discovered the art of (making metals). This probably happened in the Middle East. People used copper first, then learned how to make bronze. When people started using these metals instead of stone, the Stone Age ended and the Bronze Age began.
Some groups of people in Papua New Guinea continued to use Stone Age technology into the 20th century. They used stone-tipped weapons to kill animals for food and clothing. They made shelters using animal skin.
Food that was eaten in the Stone Age was berries (e.g. blackberries), fish, animals (e.g. mammoth) and animal organs.
Because of the Nazi government, at least 50 million people died. About 28.7 million soldiers and people died in the fighting. The war also killed 19.3 million civilians and prisoners of war. Nazi forces committed many war crimes and atrocities during the war. They killed their enemies sometimes with mobile death squads or put them in concentration camps and death camps. Hitler and his men persecuted and killed Jews and other ethnic, religious, and political minorities. In what is called the Holocaust, the Nazis killed six million Jews, Roma people, homosexuals, Slavs, and many other groups of people.
Hitler failed high school exams in Linz twice. In 1905, he left school. He became interested in the anti-Semitic (anti-Jewish), Pan-German teachings of Professor Leopold Poetsch. In September 1907, he went to Vienna and took an entrance examination. On 1 and 2 October, he failed the second examination. Hitler went back to Linz at the end of October. In December 1907, Hitler's mother died and, because of that, he was depressed. Hitler's mother was Catholic, but Hitler is not known to have been personally interested in Christianity.
In 1909, Hitler again went to Vienna to study art. He tried to become a student at the Academy of Arts, but failed the first entrance examination. He made many paintings and sold them at low prices. Hitler said he first became an anti-Semite in Vienna. This city had a large Jewish community.
In 1913, Hitler was 24 years old. At that time, all young Austrian men had to join the army. Hitler did not like the Austrian army and the Austro-Hungarian Empire because of its many ethnic groups, so he left Austria for Germany. He lived in the German city of Munich.
On 16 August 1914, Hitler joined the Bavarian army. He fought for the German Empire in World War I. Hitler served in Belgium and France in the 16th Bavarian Reserve Regiment. He spent nearly the whole time on the Western Front. He was a runner, one of the most dangerous jobs on the Front. That means he ran from one position to another one to carry messages. On 1 November 1914, Hitler became a Gefreiter (which was like being a private first class in the United States Army, or a lance corporal in the British Army). The government awarded him the Iron Cross Second Class on 2 December 1914.
In March 1918, Hitler participated in the Spring Offensive. On 4 August 1918, Hitler was awarded the Iron Cross First Class by the Jewish Hugo Gutmann. After Germany surrendered, Hitler was shocked, because the German army still held enemy area in November 1918.
Hitler is credited with starting World War II by ordering the German Army to invade Poland. His army took over western Poland, and later most of Europe, including France and a large part of the Soviet Union.
Forty hours after Hitler and Eva Braun got married in Berlin, Germany, both of them committed suicide by poisoning themselves with cyanide, then Hitler shot himself in the head with his gun. Before this, Hitler ordered that their bodies be burned. This prevented him from being captured alive by soldiers of the Red Army, who were closing in on him. Despite this, there are theories that Hitler did not die in 1945, but that he instead escaped to Argentina. These theories are very unpopular, with most historians dismissing them.
Ian Kershaw, a historian who wrote a biography (life story) of Hitler, describes him as a modern symbol of evil. "Never in history has such ruination ... been [linked] with the name of one man." However, Kershaw and some other historians believe that it is more important to look at the wider problems in Germany at the time, rather than at Hitler himself, to explain why the war and the Holocaust happened.
Publius Vergilius Maro (; traditional dates 15 October 70 BC21 September 19 BC), usually called Virgil or Vergil ( ) in English, was a poet in the Latin language. His poems are about gods and their mythology. Virgil's most famous epic poem is called the "Aeneid".
As a young man, Mozart tried but failed to establish himself as a composer in Paris. He returned to Salzburg where he was briefly employed in the court of the Archbishop of Salzburg. He was restless, aware of his genius, and thought Salzburg too small for his talent. He relocated to Vienna where he met with some success. He married Constanze Weber and fathered two sons. He died in Vienna after a brief but unknown illness.
Wolfgang Amadeus Mozart ("Wolfi" or Wolferl") was born in Salzburg to Leopold and Anna Maria Mozart. Leopold was a violinist in the orchestra of the archbishop of Salzburg and the author of a best-selling introduction to playing the violin.
Mozart's sister Maria Anna ("Nannerl") was a talented girl. The two children received their musical and academic education from their father. The family toured Europe for a few years, performing for royals and aristocrats.
During 1719, the great composer George Frideric Handel, who had moved to England, came to Germany to visit his mother. Bach wanted to meet Handel, who was only 30 km away, but these two famous musicians never met. Handel wanted to spend his limited time in Germany with his mother who was old and frail, knowing that it would be the last time he would see her.
In 1723 Bach moved to Leipzig to take the job of "Cantor" at the St Thomas Church, a very large church in the town. As "Cantor" he was in charge of all the music, both at St Thomas and at another church nearby. He also had to compose music for the town. It was an excellent job, and more secure than being at a court. The schools were good for his sons. Bach stayed in Leipzig until his death. He loved his job most of the time and worked very hard. He composed many cantatas for the church services. These services were very long, lasting about three hours. Many of the cantatas he wrote last about 30 minutes. He had assistants to play the organ. Bach himself directed the choir and the orchestra. There were probably 16 singers in the choir and 18 players in the orchestra. He wrote the "St Matthew Passion" and the "St John Passion". Both these works, which are very long, tell the story of Jesus dying on the cross. They are among the most famous pieces of music ever written. He also wrote cantatas for special occasions such as weddings or funerals.
Bach wrote many fugues, eventually he decided to write a collection called "The Art of Fugue". His plan was to publish it, but he died before he could finish it (his son later published it in his honor, as Bach's last published piece). In the last year or two of his life, he became blind in spite of two eye operations. In the 19th century more people became interested in Bach, and many of his works were published after he had been dead more than a hundred years.
The Earth's atmosphere is the layer of gasses around the Earth. It is held in place by Earth's gravity. It is today made up mainly of nitrogen (78.1%). It also has plentiful oxygen (20.9%) and small amounts of argon (0.9%), carbon dioxide (~ 0.035%), water vapor, and other gases. The atmosphere protects life on Earth by absorbing (taking) ultraviolet rays from the Sun. It makes our days cooler and our nights warmer.
The most important thing to remember about the Earth and other planets is that "they do not come from the Sun". They or their materials were picked up by the Sun's gravitation as it moved through space. The Sun is just composed of hydrogen, with a little bit of helium. Nothing else. The material which makes up planets and their satellites is almost entirely heavier elements whose origin was in earlier supernovae explosions. The planets do give off small quantities of hydrogen and helium: this comes from the decay of larger radioactive molecules whose origin is also ancient supernovae.
Regions where one layer changes to the next have been named "-pauses." So the tropopause is where the troposphere ends ( high). The stratopause is at the end of the stratosphere. The mesopause is at the end of the mesosphere.
These are boundaries.
The human penis is a male body part found on the outside of the body. It is used for urination and for sexual intercourse. The main sexual function of the penis is to be inserted into a female's vagina and deliver semen which may cause pregnancy. The penis also provides pleasure during other types of sexual activity, including foreplay, oral sex, and solo sex (which doctors say is normal and healthy).
There are many slang words for "penis". They include "dick", "cock", and "schlong". A euphemism for "penis" is "male member". The general area where the penis is located is called the crotch. Sometimes people who do not want to use the word penis use the word crotch instead. For example, someone might say a rapper "grabbed his crotch" rather than "grabbed his penis."
Females have a clitoris, which is like a penis, although the outside part of the clitoris is much smaller than the penis. Most of the clitoris is inside the body. Part of the shaft of the clitoris is covered by a thin layer of skin called the clitoral hood, which is similar to the foreskin of the penis, discussed below. Both the penis and the clitoris are erectile organs, meaning they can become larger and harder when touched, rubbed, or stimulated in other ways.
The human penis exits the abdomen above the scrotum and hangs freely outside the body. The main visible part is called the shaft.
The human penis is made up of three rod-shaped tissues. It has two corpora cavernosa (special pieces of muscle) next to each other and a corpus spongiosum (spongy muscle) between them.
The end of the corpus spongiosum forms the glans penis. The glans penis is covered by the foreskin in uncircumcised males. The rounded base of the glans is called the corona. The area on the bottom of the penis, where the foreskin is attached, is known as the frenulum of prepuce.
The urethra, the tube where urine and semen travel through, runs down the corpus spongiosum (spongy tissue), and opens at the tip of the penis. The opening is called the urinary meatus. Sperm are made in the testes (ball-like organs) and stored in the epididymis (layer of tissue) around the testes. During ejaculation, sperm are pushed up the vas deferens. Fluids are added by the seminal vesicles, the prostate gland and the bulbourethral glands to make semen.
A penis can become erect ("hard") if a male is sexually aroused (or sometimes during sleep, even though there is no sexual stimulation). In an erection, the penis fills with blood. The blood makes the penis become longer, thicker and harder. Veins taking blood away from the penis get smaller, so less blood is taken through. Arteries bringing blood to the penis get wider, bringing more blood to the penis. Erections sometimes occur in the male fetus (before birth), and occur naturally from birth onwards. It is normal for the penis to be erect when a male wakes up. This is commonly called morning wood. It is also normal for male teenagers and men to have an erection several times per night when sleeping. If this does not happen, the person may have a bad medical problem or depression (a mental health problem.) Not being able to have an erection can also be caused by various common drugs, including antidepressants and drugs taken to control high blood pressure. During the day, an erection sometimes happens for no reason, or when undressing. This is most common in young teenagers and is normal. People call this a "spontaneous" (sudden or surprise) erection. A slang word for an erection is a "boner."
Ejaculation is when semen is pushed from the penis. It usually happens during an orgasm. Males can ejaculate during sexual intercourse or by masturbation. There are usually 40 million or more sperm in the semen ejaculated. Semen usually has a slight smell of chlorine and ammonia. It is not poisonous, but it is very bad if it gets in someone's eye. The enzymes semen contains to penetrate the egg in a female will also attack the eye. Be careful not to ejaculate into your eye or your partner's eye. Semen contains proteins and fructose (a kind of sugar.) Some people say it tastes sweeter if the man eats a lot of fruit. Scientists have not proven that. Smoking, or drinking coffee, tea or colas that contain caffeine can create a bitter flavor. Semen is slimy when wet. Eventually, it dries in the air and hardens like glue.
In reproductive sexual intercourse between a male and female, the erect penis is inserted into the vagina and moved in and out. The vagina places pressure on the penis, which can cause the male to have an orgasm and ejaculate into the vagina, causing insemination (meaning that semen enters the female's reproductive system.)
Orgasm and ejaculation can happen during many types of sex acts including anal and oral sex, and when masturbating. A condom should be used during anal sex to avoid getting a urinary tract infection. Masturbation can include touching and rubbing the penis and other sensitive areas of the body, such as the scrotum, and other places in the genital area. This can be done naked or through clothes. Sometimes the penis is squeezed between the partner's thighs without being inserted into the body. This is called intercrural sex. Sometimes the penis is rubbed against the other person's body. The people can be naked or wearing clothes. When two males rub their penises together or against each other's body, it is called frottage. Ejaculation may also happen without touching during sleep (called a 'wet dream'). This is common, especially for pre-teen and teenage boys. It is uncommon in adults. While it can feel almost magical to ejaculate during a dream, boys don't like the mess it creates. Boys usually don't have wet dreams if they masturbate before sleeping every night. A male must have started puberty before he can ejaculate. (Sometimes when a boy who has not started puberty masturbates, a small amount of urine comes out.) During orgasm, muscles push semen from the penis. Semen moves through the urethra and comes out of the hole at the tip of the penis.
A man can put a condom on his penis to prevent semen from entering the female's reproductive system. A condom is very thin, so having sex still feels good. It is normally made of latex. If used correctly, a condom usually stops the woman from getting pregnant and having a baby. The condom also lowers the chance of getting a sexually transmitted infection from the sexual partner or giving a sexually transmitted infection to the sexual partner. While condoms are most commonly used during vaginal sex, a condom can also be used during oral sex, anal sex, and masturbation.
Vaccinating young people (both girls and boys) before the age when they first have sex can reduce their risk of getting one infection called HPV. The United States CDC says the HPV vaccine should be given at age 11 or 12 years but can be started at age 9. HPV increases the risk of cancer, including cancer in the throat or neck if people have oral sex (licking, kissing or sucking on the penis.) HPV can be under the foreskin if the penis has a foreskin, and in the semen whether the penis is circumcised or uncircumcised.
The human penis is longer than in other primates except for the chimpanzee. The chimpanzee's penis is about the same length. The penis is bigger in circumference on humans than on other primates.
The foreskin is a fold of skin that covers the end of the penis. The foreskin is a bit thicker than an eyelid. Cutting off the foreskin is called circumcision. The foreskin is connected to the head of the penis. During circumcision, most or all of the foreskin is removed from the penis. This simple change to the penis is very common in many countries of the world including the United States and Israel. Circumcision is done for medical reasons because it lowers the chance of ever getting cancer of the penis to near zero. The foreskin removed during circumcision is a possible source of penile cancer. Childhood circumcision has a strong protective effect against penile cancer in later life. Penile cancer has been nearly eliminated in populations of males circumcised shortly after birth. Circumcision virtually eliminates the risk of invasive penile cancer. Being uncircumcised is a risk factor for penile cancer. Invasive penile cancer is cancer that spreads in the body. It is uncommon but often causes the man to die. Circumcision also reduces the risk of cancer of the cervix in female sexual partners. Cervical cancer is very common. It causes over 300,000 deaths of women worldwide every year. Circumcision reduces, but does not eliminate, the risk of getting or spreading HIV/AIDS. Circumcision became more common in Africa after HIV/AIDS began. The use of condoms also reduces the risk of getting or spreading HIV/AIDS, but many people in Africa cannot afford condoms or choose not to use them.
Circumcision is usually performed on infant males for medical reasons, or for religious reasons, especially for Jews and Muslims, or cultural reasons in the United States, the Philippines, and South Korea. "Cultural reasons" means reasons such as beliefs that the penis stays cleaner or looks more beautiful when circumcised. "Cultural reasons" also includes tradition, meaning parents wanting their son's penis to look like the father's penis and like other boys' penises. In the United States, one of the reasons for it being a tradition is that it was once a requirement in the navy and popular in other parts of the military. The World Health Organization estimates that the overall male circumcision rate in the United States is somewhere between 76 and 92 percent. Circumcision was also very common in Canada, although that is no longer the case, due in part to changes in government rules about paying for circumcision. Through the first half of the twentieth century, up to about the late 1960s and even the early 1970s, it was common for men in the United States and Canada to swim naked (without bathing suits) at high school, college, and YMCA pools. It was also common that men showered together in schools and in the military. Since it was common for boys and young men to be naked, many parents wanted their sons to look like other American males. Parents did not want their sons to look different from the majority.
Some males have the foreskin cut off when they are adults because they have problems with their foreskin. Some males have the foreskin cut off because they want to change how their penis looks. Few boys are born without a foreskin or with a very short foreskin, called aposthia, naturally circumcised.
In common speech, you can say that someone is "cut" or "uncut", meaning circumcised or not circumcised. For example, one teenage boy might ask another teenage boy, "Are you cut?" While this is slang English, it is not considered profanity.
In some religions, babies and young boys have their foreskins cut off. This is expected in Islam and Judaism. It is not required according to Christianity. Among Christians in the United States, it is more common among Protestants than among Catholics. In the United States, circumcision is less common among boys and men whose families came from Mexico, who are usually Catholic. In Judaism, infant males are required to have their foreskin removed as a sign of the covenant (ancient promise) made with God.
When a foreskin is removed from a baby, doctors can use the skin for important medical purposes. Doctors can replace skin on someone with burns or with foot sores caused by diabetes. Foreskins that have been removed can be used for medical research.
If a male is uncut (uncircumcised) he should wash under the foreskin every day. However, young boys should not pull or push their foreskin back when washing. Not washing can cause a bad smell. People should not use soap when washing their penis. Getting soap inside the penis (in the urethra) can hurt. It is like getting soap in the eyes.
Penile skin is often slightly darker than skin in surrounding areas. This is due to a higher concentration of melanocytes in genital skin tissue. The tip (glans) of the penis is usually pink or red color even if the penis shaft skin is dark. If the man is not circumcised, the tip is usually covered by the foreskin. The foreskin is about the same color as the skin on the shaft of the penis.
If a man's penis skin changes color and he doesn't know why, he should go to a doctor. He could have an infection, diabetes or cancer. A sunburn on the penis can happen quickly. If a man is outside without clothes, he will get a sun tan. That is normal. Too much sun causes sunburn. Doctors say to use sunscreen (sun cream) before and after nude swimming. A sunburn can happen in a few minutes on a very sunny day.
Since the oldest cultures the penis has assumed a strong importance as a symbol of fertility used also in religious ceremonies to celebrate and (people hoped) to improve the reproductive capacity of men and beasts. For example, in Roman paganism, the god Priapus is characterized by a huge penis. In some places in Japan and South Korea, there are special days and public events to celebrate the penis. When an erect penis is shown in art or in cultural events, it is often called a phallus.
Some men put jewelry on their penis. This is a type of body piercing called genital piercing. One main reason is that it can make sex more pleasurable. Jewelry is sometimes at the tip (through the glans and urethra), sometimes through the foreskin, corona, or frenulum, or sometimes under the shaft of the penis.
The Sahara has one of the world's most harsh climates. Typically, the Sahara landscape experiences little rainfall, powerful winds and wide temperature ranges. In some areas, there can be no rainfall for years at a time.
In the summer, daytime air temperatures across the Sahara often reach over 100 degrees Fahrenheit. In the winter the freezing temperatures may occur in the northern Sahara, and milder temperatures, across the southern Sahara. Snow may fall occasionally in some of the higher mountain ranges and rarely, on the desert floor.
Paris (nicknamed the ""City of light"") is the capital city of France, and the largest city in France. The area is , and around 2.15 million people live there. If suburbs are counted, the population of the Paris area rises to 10.7 million people. It is the most densely populated city in the European Union, with 20.653 people per square kilometer.
Julius Caesar conquered the Celtic "Parisii" tribe in 51 BC. The largest clan of French people in Paris is Parisii in 2023. The Romans called the place "Lutetia" of the Parisii, or ""Lutetia Parisiorum"". The place got a shorter name, ""Paris"", in 212 AD.
As the Roman Empire began to fall apart in the West, the Germanic tribe called the Franks moved in, taking it in 464. In 507, their king Clovis I made it his capital. Charlemagne moved his capital to Aachen in Germany, but Paris continued as an important town and was attacked by the Vikings twice. When Hugh Capet became king of France in 987, he again made Paris his capital. For a long time, the kings only controlled Paris and the surrounding area, as much of the rest of France was in the hands of barons or English. During the Hundred Years' War, the English controlled Paris from 1420 to 1437.
Paris was the Capital of the French Empire which, as well as France, covered Spain, Belgium, Holland, Luxembourg, Switzerland, Italy, most of Germany and some of Austria, Croatia, Slovenia and Poland. The Empire ruled by Napoleon was from 1804 to 1814/1815. The Russian army seized Paris from Napoleon in 1814, and the Prussian army captured it in 1871. The next time it was captured was by the Nazi Germans in 1940. The Allies freed the city in 1944 and it has not since been captured.
Also, the city has been featured in many songs including the #1 hit song by Jay-Z and Kanye West called "Niggas in Paris".
The Holocaust, sometimes called The "Shoah" (""), was a genocide in which Nazi Germany systematically killed mainly Jews during World War II. six million Jews were killed, as well as five million others that the Nazis claimed were inferior (mainly Slavs, communists, Roma people, disabled people, homosexuals, and Jehovah's Witnesses). These people were rounded up, put in ghettos, forced to work in extermination camps, and then killed in gas chambers.
There was hatred and persecution of Jews (Anti-Semitism) in Europe for hundreds of years. Many people wrongly thought that all Jews became rich by stealing money from other people, such as Christians; that they did not like people other than their fellow Jews; and that they harmed children to use their blood for religious rituals (blood libel). These beliefs were not true and were based on stereotypes and prejudices.
People who were semitic (Jewish) were killed to begin with by carbon monoxide from motor-vehicle exhaust pipes, then by a rat-poison which contained cyanide, named Zyklon-B for selling. Zyklon was especially used in Auschwitz and one other camp.