The asteroid belt is the circumstellar disc in the Solar System located between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called minor planets; the asteroid belt is termed the main asteroid belt or main belt to distinguish it from other asteroid populations in the Solar System such as near-Earth asteroids and trojan asteroids. About half the mass of the belt is contained in the four largest asteroids: Ceres, Vesta and Hygiea; the total mass of the asteroid belt is 4% that of the Moon, or 22% that of Pluto, twice that of Pluto's moon Charon. Ceres, the asteroid belt's only dwarf planet, is about 950 km in diameter, whereas 4 Vesta, 2 Pallas, 10 Hygiea have mean diameters of less than 600 km; the remaining bodies range down to the size of a dust particle. The asteroid material is so thinly distributed that numerous unmanned spacecraft have traversed it without incident. Nonetheless, collisions between large asteroids do occur, these can produce an asteroid family whose members have similar orbital characteristics and compositions.
Individual asteroids within the asteroid belt are categorized by their spectra, with most falling into three basic groups: carbonaceous and metal-rich. The asteroid belt formed from the primordial solar nebula as a group of planetesimals. Planetesimals are the smaller precursors of the protoplanets. Between Mars and Jupiter, gravitational perturbations from Jupiter imbued the protoplanets with too much orbital energy for them to accrete into a planet. Collisions became too violent, instead of fusing together, the planetesimals and most of the protoplanets shattered; as a result, 99.9% of the asteroid belt's original mass was lost in the first 100 million years of the Solar System's history. Some fragments found their way into the inner Solar System, leading to meteorite impacts with the inner planets. Asteroid orbits continue to be appreciably perturbed whenever their period of revolution about the Sun forms an orbital resonance with Jupiter. At these orbital distances, a Kirkwood gap occurs. Classes of small Solar System bodies in other regions are the near-Earth objects, the centaurs, the Kuiper belt objects, the scattered disc objects, the sednoids, the Oort cloud objects.
On 22 January 2014, ESA scientists reported the detection, for the first definitive time, of water vapor on Ceres, the largest object in the asteroid belt. The detection was made by using the far-infrared abilities of the Herschel Space Observatory; the finding was unexpected because comets, not asteroids, are considered to "sprout jets and plumes". According to one of the scientists, "The lines are becoming more and more blurred between comets and asteroids." In 1596, Johannes Kepler predicted “Between Mars and Jupiter, I place a planet” in his Mysterium Cosmographicum. While analyzing Tycho Brahe's data, Kepler thought that there was too large a gap between the orbits of Mars and Jupiter. In an anonymous footnote to his 1766 translation of Charles Bonnet's Contemplation de la Nature, the astronomer Johann Daniel Titius of Wittenberg noted an apparent pattern in the layout of the planets. If one began a numerical sequence at 0 included 3, 6, 12, 24, 48, etc. doubling each time, added four to each number and divided by 10, this produced a remarkably close approximation to the radii of the orbits of the known planets as measured in astronomical units provided one allowed for a "missing planet" between the orbits of Mars and Jupiter.
In his footnote, Titius declared "But should the Lord Architect have left that space empty? Not at all."When William Herschel discovered Uranus in 1781, the planet's orbit matched the law perfectly, leading astronomers to conclude that there had to be a planet between the orbits of Mars and Jupiter. On January 1, 1801, Giuseppe Piazzi, chair of astronomy at the University of Palermo, found a tiny moving object in an orbit with the radius predicted by this pattern, he dubbed it "Ceres", after the Roman goddess of the patron of Sicily. Piazzi believed it to be a comet, but its lack of a coma suggested it was a planet. Thus, the aforementioned pattern, now known as the Titius–Bode law, predicted the semi-major axes of all eight planets of the time. Fifteen months Heinrich Olbers discovered a second object in the same region, Pallas. Unlike the other known planets and Pallas remained points of light under the highest telescope magnifications instead of resolving into discs. Apart from their rapid movement, they appeared indistinguishable from stars.
Accordingly, in 1802, William Herschel suggested they be placed into a separate category, named "asteroids", after the Greek asteroeides, meaning "star-like". Upon completing a series of observations of Ceres and Pallas, he concluded, Neither the appellation of planets nor that of comets, can with any propriety of language be given to these two stars... They resemble small stars so much. From this, their asteroidal appearance, if I take my name, call them Asteroids. By 1807, further investigation revealed two new objects in the region: Vesta; the burning of Lilienthal in the Napoleonic wars, where the main body of work had been done, brought this first period of discovery to a close. Despite Herschel's coinage, for several decades it remained common practice to refer to these objects as planets and to prefix t
Tomorrow and Tomorrow (novel)
Tomorrow and Tomorrow is a 1997 science fiction novel by Charles Sheffield. The book starts in the year 2020 and follows the protracted adventures of Drake Merlin, in his obsessive quest to save his wife from a terminal brain disease, over the course of eons. Similar premises are presented in the 2006 film The Fountain, as well as the Isaac Asimov story "The Last Question". Drake is a professional musician, with minor celebrity; when his wife Ana is diagnosed with an unspecified incurable brain disorder, Drake exhausts every option attempting to cure her. Only does he decide to have her body cryogenically stored, in the hopes future generations will discover an effective treatment. However, Drake is cautious, in case the future culture doesn't care about her plight, he has himself frozen as well. Furthermore, he devotes all his energies for a decade before his freezing to becoming an expert primary source on the musically notable people of his era, he assumes that if you become the world's foremost expert in any subject someone will want to write a book on that exact subject.
At that time the hypothetical future writer will want to awaken Drake, he can in turn awaken his wife, if treatment is available. He is awakened in the year 2500. Although society is vastly different, no cure for Ana yet exists, he spends six years apprenticed to a musical historian to pay for his reviving costs and to gain a foothold in this new world. Drake is continually laid dormant and revived, progressively into the future, all the way until the time of the Big Crunch. Human civilization alters radically over the eons, but Ana's mangled brain proves an difficult problem. Despite the incomprehensible changes surrounding in each successive awakening, Drake never loses sight of his mission. In the remote posthuman future a few billions years Drake's original biological body has disintegrated, despite the cryogenic treatment, he has become an uploaded consciousness, though still in stasis. At this point the descendants of humanity have colonized the entire Milky Way galaxy, yet an inexplicable threat is wiping out their colonies in a widening arc.
The leaders of this civilization have exhausted every answer they can conceive of and have zero information as to the cause of the threat. Their last hope is an ancient holdover, who may have ideas new to them -- namely, war; the main problem is that the beings have no idea what is happening because the planets wiped out seem the same, but they do not respond to signals, outside communication is impossible. All probes sent do not return, nor do they reply once they reach the surface of the planet. Drake becomes the commander of the residents of the galaxy, in designing weapons and defenses, ideas that have long vanished from the minds of these beings. At this time, their technology allows for powerful and deep manipulation of matter at a fundamental scale. An experimental technology called, it is a means of instantaneous teleportation using exotic physics, which has by now developed to a stage where it will have no meaning to the causal being. This caesura has a low chance of succeeding. Billions upon billions of copies of Drake are thus sent out to the planets on the border of the invasion, by means of the caesura they are teleported back to the base to collect information about the threat.
It is discovered that the threat is an exotic interplanetary type of plant life with spores that migrate between systems. These plants do not intentionally destroy the living beings on the planet, but as a result of their growth they do so. After the cause of the problem is found, the posthumans decide that the militant Drake is no longer needed or deemed a positive influence—he is seen as too warlike, they tell him to merge with all the returning Drake copies. This he agrees to, over billions of years, he collates those copies—forming a collective mind of copies of himself. In one subplot, a version of himself was randomly teleported by the caesura to a distant galaxy, he manages to return over a few billion years; the collective version of Drake resolves to use the Omega Point to gain complete knowledge of everything and to restore Ana. The story ends on an ambiguous note as Ana is revived, they seek to create a new universe by means of the caesura to live in
Asteroids are minor planets of the inner Solar System. Larger asteroids have been called planetoids; these terms have been applied to any astronomical object orbiting the Sun that did not resemble a planet-like disc and was not observed to have characteristics of an active comet such as a tail. As minor planets in the outer Solar System were discovered they were found to have volatile-rich surfaces similar to comets; as a result, they were distinguished from objects found in the main asteroid belt. In this article, the term "asteroid" refers to the minor planets of the inner Solar System including those co-orbital with Jupiter. There exist millions of asteroids, many thought to be the shattered remnants of planetesimals, bodies within the young Sun's solar nebula that never grew large enough to become planets; the vast majority of known asteroids orbit within the main asteroid belt located between the orbits of Mars and Jupiter, or are co-orbital with Jupiter. However, other orbital families exist with significant populations, including the near-Earth objects.
Individual asteroids are classified by their characteristic spectra, with the majority falling into three main groups: C-type, M-type, S-type. These were named after and are identified with carbon-rich and silicate compositions, respectively; the sizes of asteroids varies greatly. Asteroids are differentiated from meteoroids. In the case of comets, the difference is one of composition: while asteroids are composed of mineral and rock, comets are composed of dust and ice. Furthermore, asteroids formed closer to the sun; the difference between asteroids and meteoroids is one of size: meteoroids have a diameter of one meter or less, whereas asteroids have a diameter of greater than one meter. Meteoroids can be composed of either cometary or asteroidal materials. Only one asteroid, 4 Vesta, which has a reflective surface, is visible to the naked eye, this only in dark skies when it is favorably positioned. Small asteroids passing close to Earth may be visible to the naked eye for a short time; as of October 2017, the Minor Planet Center had data on 745,000 objects in the inner and outer Solar System, of which 504,000 had enough information to be given numbered designations.
The United Nations declared 30 June as International Asteroid Day to educate the public about asteroids. The date of International Asteroid Day commemorates the anniversary of the Tunguska asteroid impact over Siberia, Russian Federation, on 30 June 1908. In April 2018, the B612 Foundation reported "It's 100 percent certain we'll be hit, but we're not 100 percent sure when." In 2018, physicist Stephen Hawking, in his final book Brief Answers to the Big Questions, considered an asteroid collision to be the biggest threat to the planet. In June 2018, the US National Science and Technology Council warned that America is unprepared for an asteroid impact event, has developed and released the "National Near-Earth Object Preparedness Strategy Action Plan" to better prepare. According to expert testimony in the United States Congress in 2013, NASA would require at least five years of preparation before a mission to intercept an asteroid could be launched; the first asteroid to be discovered, was considered to be a new planet.
This was followed by the discovery of other similar bodies, with the equipment of the time, appeared to be points of light, like stars, showing little or no planetary disc, though distinguishable from stars due to their apparent motions. This prompted the astronomer Sir William Herschel to propose the term "asteroid", coined in Greek as ἀστεροειδής, or asteroeidēs, meaning'star-like, star-shaped', derived from the Ancient Greek ἀστήρ astēr'star, planet'. In the early second half of the nineteenth century, the terms "asteroid" and "planet" were still used interchangeably. Overview of discovery timeline: 10 by 1849 1 Ceres, 1801 2 Pallas – 1802 3 Juno – 1804 4 Vesta – 1807 5 Astraea – 1845 in 1846, planet Neptune was discovered 6 Hebe – July 1847 7 Iris – August 1847 8 Flora – October 1847 9 Metis – 25 April 1848 10 Hygiea – 12 April 1849 tenth asteroid discovered 100 asteroids by 1868 1,000 by 1921 10,000 by 1989 100,000 by 2005 ~700,000 by 2015 Asteroid discovery methods have improved over the past two centuries.
In the last years of the 18th century, Baron Franz Xaver von Zach organized a group of 24 astronomers to search the sky for the missing planet predicted at about 2.8 AU from the Sun by the Titius-Bode law because of the discovery, by Sir William Herschel in 1781, of the planet Uranus at the distance predicted by the law. This task required that hand-drawn sky charts be prepared for all stars in the zodiacal band down to an agreed-upon limit of faintness. On subsequent nights, the sky would be charted again and any moving object would be spotted; the expected motion of the missing planet was about 30 seconds of arc per hour discernible by observers. The first object, was not discovered by a member of the group, but rather by accident in 1801 by Giuseppe Piazzi, director of the observatory of Palermo in Sicily, he discovered a new star-like object in Taurus and followed the displacement of this object during several nights. That year, Carl Friedrich Gauss used these observations to calculate the orbit of this unknown object, found to be between the planets Mars and Jupiter.
Piazzi named it after Ceres, the Roman goddess of agriculture. Three other asteroids (2 Pallas, 3 Juno, 4 Ves
The Cyborg from Earth
The Cyborg from Earth is a 1998 science fiction novel by Charles Sheffield. It is the fourth in a series of unrelated stories, published by Tor Books in their Jupiter line; the novel starts in a future dystopian Earth where the upper class lives a life of privilege, while most others live in the "pool", an endless crowd of unemployable youths depending on government assistance or crime for survival. The book is told from the perspective of the main character, Jefferson Kopal, a young member of an immensely wealthy and powerful spaceship building family founded by his Great Grandfather, Rollo Kopal, an admiral in the Space Navy; as part of the bylaws, all voting members of the company must have served honorably in the navy. Young Jeff is about to take his final test... "Jefferson Kopal is a coward. He knows it, if he doesn't do something about it soon, so will everyone else." This is the self-evaluation of the novel's main protagonist. Jeff is about to take his final test before a Navy Review Board to see if he is fit for duty as an officer in the Space Navy.
After failing the test most valiantly, Jeff is assigned to the Navy's Border Command, an apparent exile from the solar system and prestigious Central Command, where all the great Kopals have served. Jeff is assigned to a ship that will take him into the Messina Dust Cloud, which residents of the Solar System call Cyborg Territory. After a confrontation with his cousin, Jeff heads into space. Adjustment to naval life is at first hard on engineers, he is able to show his true interest, engineering. Captain Dufferin, the Commanding Officer, feels that the Kopals are a plague on the Space Navy and intends to make Jeff suffer for his last name. Jeff is sent to the forward observation bubble prior to the jump to The Messina Dust Cloud. While contemplating his current situation, Jeff notices the formation of a "space sounder," a terrifying anomaly, known to destroy whole star ships, coming directly for the ship. Jeff warns the Bridge but blacks out as the ship takes evasive action to avoid certain death.
When Jeff awakes, he finds that he has been abandoned by Captain Dufferin and the majority of the crew. Mercy Hooglich, one of the'jinners Jeff had befriended, explains how the captain and other officers had taken the runabout back to the Solar System, are going to charge Jeff with dereliction of duty. Jeff learns that his injuries were so extensive that to be saved, the medical technology of the Cloud, nanotechnology, had to be used; the remainder of the story revolves around the "rebellion" of the Cloud Territory as well as Jeff fighting to restore his name and place in the family business. In the end, Jeff finds that he is not a coward and everyone else knows that as well; the engines used by Vanguard Mining's spacecraft are Diabelli Omnivores. This particular brand of engine is used throughout Sheffield's books, across many different fictional settings
Divergence is a science fiction novel by American writer Charles Sheffield, part of his Heritage Universe series. The book, the sequel to Summertide, takes place millennia in the future when most of the Orion Arm of the galaxy has been colonized by humans and other races. Among the various star systems of this arm of the galaxy, a number of million-year-old artifacts have been discovered, remnants of a mysterious race called the Builders; the characters of this book start just a few days after the previous book left off to go in search of a newly discovered artifact. This book introduces a few new characters; the characters work together to discover a new theory about the origins and current condition of the Builders. During this process, they discover that an old menace to the universe, thought to be extinct, has been unleashed upon the Orion Arm of the Milky Way once again; the novel includes excerpts from the Lang Universal Artifact Catalog, from the Universal Species Catalog. The sequel to Divergence is Transcendence
Dictionaries traditionally define literacy as the ability to read and write. In the modern world, this is one way of interpreting literacy. One more broad interpretation sees literacy as competence in a specific area; the concept of literacy has evolved in meaning. The modern term's meaning has been expanded to include the ability to use language, images and other basic means to understand, gain useful knowledge, solve mathematical problems and use the dominant symbol systems of a culture; the concept of literacy is expanding across OECD countries to include skills to access knowledge through technology and ability to assess complex contexts. A person who travels and resides in a foreign country but is unable to read or write in the language of the host country would be regarded by the locals as illiterate; the key to literacy is reading development, a progression of skills which begins with the ability to understand spoken words and decode written words, which culminates in the deep understanding of text.
Reading development involves a range of complex language-underpinnings including awareness of speech sounds, spelling patterns, word meaning and patterns of word formation, all of which provide a necessary platform for reading fluency and comprehension. Once these skills are acquired, a reader can attain full language literacy, which includes the abilities to apply to printed material critical analysis and synthesis; the inability to do so is called "illiteracy" or "analphabetism". Experts at a United Nations Educational and Cultural Organization meeting have proposed defining literacy as the "ability to identify, interpret, create and compute, using printed and written materials associated with varying contexts"; the experts note: "Literacy involves a continuum of learning in enabling individuals to achieve their goals, to develop their knowledge and potential, to participate in their community and wider society". Literacy emerged with the development of numeracy and computational devices as early as 8000 BCE.
Script developed independently at least five times in human history Mesopotamia, the Indus civilization, lowland Mesoamerica, China. The earliest forms of written communication originated in Serbia, followed by Sumer, located in southern Mesopotamia about 3500-3000 BCE. During this era, literacy was "a functional matter, propelled by the need to manage the new quantities of information and the new type of governance created by trade and large scale production". Writing systems in Mesopotamia first emerged from a recording system in which people used impressed token markings to manage trade and agricultural production; the token system served as a precursor to early cuneiform writing once people began recording information on clay tablets. Proto-cuneiform texts exhibit not only numerical signs, but ideograms depicting objects being counted. Egyptian hieroglyphs emerged from 3300-3100 BCE and depicted royal iconography that emphasized power amongst other elites; the Egyptian hieroglyphic writing system was the first notation system to have phonetic values.
Writing in lowland Mesoamerica was first put into practice by the Olmec and Zapotec civilizations in 900-400 BCE. These civilizations used glyphic writing and bar-and-dot numerical notation systems for purposes related to royal iconography and calendar systems; the earliest written notations in China date back to the Shang Dynasty in 1200 BCE. These systematic notations were found inscribed on bones and recorded sacrifices made, tributes received, animals hunted, which were activities of the elite; these oracle-bone inscriptions were the early ancestors of modern Chinese script and contained logosyllabic script and numerals. Indus script is pictorial and has not been deciphered yet, it may not include abstract signs. It is thought that the script is thought to be logographic; because it has not been deciphered, linguists disagree on whether it is a complete and independent writing system. These examples indicate that early acts of literacy were tied to power and chiefly used for management practices, less than 1% of the population was literate, as it was confined to a small ruling elite.
According to social anthropologist Jack Goody, there are two interpretations that regard the origin of the alphabet. Many classical scholars, such as historian Ignace Gelb, credit the Ancient Greeks for creating the first alphabetic system that used distinctive signs for consonants and vowels, but Goody contests, "The importance of Greek culture of the subsequent history of Western Europe has led to an over-emphasis, by classicists and others, on the addition of specific vowel signs to the set of consonantal ones, developed earlier in Western Asia". Thus, many scholars argue that the ancient Semitic-speaking peoples of northern Canaan invented the consonantal alphabet as early as 1500 BCE. Much of this theory's development is credited to English archeologist Flinders Petrie, who, in 1905, came across a series of Canaanite inscriptions located in the turquoise mines of Serabit el-Khadem. Ten years English Egyptologist Alan Gardiner reasoned that these letters contain an alphabet, as well as references to the Canaanite goddess Asherah.
In 1948, William F. Albright deciphered the text using additional evidence, discovered subsequent to G