Outer space, or space, is the expanse that exists beyond the Earth and between celestial bodies. Outer space is not empty—it is a hard vacuum containing a low density of particles, predominantly a plasma of hydrogen and helium, as well as electromagnetic radiation, magnetic fields, neutrinos and cosmic rays; the baseline temperature of outer space, as set by the background radiation from the Big Bang, is 2.7 kelvins. The plasma between galaxies accounts for about half of the baryonic matter in the universe. Local concentrations of matter have condensed into galaxies. Studies indicate that 90% of the mass in most galaxies is in an unknown form, called dark matter, which interacts with other matter through gravitational but not electromagnetic forces. Observations suggest that the majority of the mass-energy in the observable universe is dark energy, a type of vacuum energy, poorly understood. Intergalactic space takes up most of the volume of the universe, but galaxies and star systems consist entirely of empty space.
Outer space does not begin at a definite altitude above the Earth's surface. However, the Kármán line, an altitude of 100 km above sea level, is conventionally used as the start of outer space in space treaties and for aerospace records keeping; the framework for international space law was established by the Outer Space Treaty, which entered into force on 10 October 1967. This treaty precludes any claims of national sovereignty and permits all states to explore outer space. Despite the drafting of UN resolutions for the peaceful uses of outer space, anti-satellite weapons have been tested in Earth orbit. Humans began the physical exploration of space during the 20th century with the advent of high-altitude balloon flights; this was followed by manned rocket flights and manned Earth orbit, first achieved by Yuri Gagarin of the Soviet Union in 1961. Due to the high cost of getting into space, manned spaceflight has been limited to low Earth orbit and the Moon. On the other hand, unmanned spacecraft have reached all of the known planets in the Solar System.
Outer space represents a challenging environment for human exploration because of the hazards of vacuum and radiation. Microgravity has a negative effect on human physiology that causes both muscle atrophy and bone loss. In addition to these health and environmental issues, the economic cost of putting objects, including humans, into space is high. In 350 BCE, Greek philosopher Aristotle suggested that nature abhors a vacuum, a principle that became known as the horror vacui; this concept built upon a 5th-century BCE ontological argument by the Greek philosopher Parmenides, who denied the possible existence of a void in space. Based on this idea that a vacuum could not exist, in the West it was held for many centuries that space could not be empty; as late as the 17th century, the French philosopher René Descartes argued that the entirety of space must be filled. In ancient China, the 2nd-century astronomer Zhang Heng became convinced that space must be infinite, extending well beyond the mechanism that supported the Sun and the stars.
The surviving books of the Hsüan Yeh school said that the heavens were boundless, "empty and void of substance". The "sun and the company of stars float in the empty space, moving or standing still"; the Italian scientist Galileo Galilei knew that air had mass and so was subject to gravity. In 1640, he demonstrated. However, it would remain for his pupil Evangelista Torricelli to create an apparatus that would produce a partial vacuum in 1643; this experiment resulted in the first mercury barometer and created a scientific sensation in Europe. The French mathematician Blaise Pascal reasoned that if the column of mercury was supported by air the column ought to be shorter at higher altitude where the air pressure is lower. In 1648, his brother-in-law, Florin Périer, repeated the experiment on the Puy de Dôme mountain in central France and found that the column was shorter by three inches; this decrease in pressure was further demonstrated by carrying a half-full balloon up a mountain and watching it expand contract upon descent.
In 1650, German scientist Otto von Guericke constructed the first vacuum pump: a device that would further refute the principle of horror vacui. He noted that the atmosphere of the Earth surrounds the planet like a shell, with the density declining with altitude, he concluded that there must be a vacuum between the Moon. Back in the 15th century, German theologian Nicolaus Cusanus speculated that the Universe lacked a center and a circumference, he believed that the Universe, while not infinite, could not be held as finite as it lacked any bounds within which it could be contained. These ideas led to speculations as to the infinite dimension of space by the Italian philosopher Giordano Bruno in the 16th century, he extended the Copernican heliocentric cosmology to the concept of an infinite Universe filled with a substance he called aether, which did not resist the motion of heavenly bodies. English philosopher William Gilbert arrived at a similar conclusion, arguing that the stars are visible to us only because they are surrounded by a thin aether or a void.
This concept of an aether originated with ancient Greek philosophers, including Aristotle, who conceived of it as the medium through which the heavenly bodies move. The concept of a Universe filled with a luminiferous aether retained support among some scientists until the early 20th century; this form of aether was viewed as the medium through whi
Juja is a town in Kiambu County in Kenya. It is the home town for Jomo Kenyatta University of Technology, it is a constituency in Kiambu county represented in parliament by Hon Francis Munyua Waititu. The MCA is Kalpesh Jayantilal Shah. Representing the great people of Juja Ward at the County Government; the town hosts the main headquarters of Shujaa Host. It was voted the best in its field for the year 2019. There are several industries in Juja, home to Juja Paper which recycles brown paper. Star Plastics is another manafactuerer which makes other plastic products. Safari Stationers manufacturers of stationery products. Hydro Aluminum makers of aluminum profiles. Juja is home to The Juja City Mall, Juja Preparatory School, Mang'u High School and parts of Thika superhighway. Juja is home to Truehost Cloud, A web hosting and domain registration company The town is located about 30 kilometers North of Nairobi between Thika and Ruiru towns; the Nairobi Business Park is found in the environs of this town.
One should keep in mind that Juja is under the Nairobi Metropolitan Authority as envisaged in the Vision 2030 of Kenya. It has 156,041. Private records from McMillan Memorial Library indicate that sometimes in 1900 when Lord William Northrop Macmillan arrived in Nairobi he was carrying two statues he had bought in West Africa, he had been told that one was Ju and the other was Ja and had been asked to preserve them – otherwise he would perish at sea. McMillan settled on the road to Thika where he bought some 19,000 acres, at a time when nobody was allowed to own more than 5,000 acres, he attributed it to the powers of Ju and Ja idols and as a result he named the large expanse Ju-Ja Farm. Because of the numerous superstition that surrounded Juja Farm, it became a no-go zone and locals used to fear entry into a land they always heard had been jinxed; as a result, McMillan’s wife took the two idols from the house and buried them in Ndarugu valley, near Thika Town. As a result, the name Juja started entering into annals of colonial history in Kenya and refused to give way to its former name ‘Weru wa Ndarugu’, the Ndarugu plains.
Juja Constituency is having 5 Wards namely Juja,Murera,Theta,Kalimoni and Witithie. Juja Ward has the highest population out of the 5 wards. Juja Ward has a lot of centers namely 1)Muchatha 2)Kanini Farm 3) Shalom 4)HardRock 5)Boma estate 6)Kay's 7) Murehma 8) Croton E 9) Riverside Kibii 10) Kipipiri 11) Mathare 12) Eastleigh 13) Mlandizi 14) Josephine's 15) Riverside Juja 16) Carnation 17) Orion 18) Greenfield 19) Joyland 20) United 21) Makena 22) Bomblast 23) Danemas 24) White house 25) Oasis 26)Kifariti 27) St Mary's 28) Woodland 29) Waroma 30)Mirimaini 31) Number4 32) George's 33) Munghetto 34) Ol Kaluo 35) Molo 36) Kisumu Ndogo 37) Westview 38) Kanawa 39) Chemi Chemi 40)Mashanani 41) Baba Martins 42) Gachororo Farmers 43) Kiaora 44) Nesco 45) Azania 46) St Paul's 47) Dam View 48)Titanic 49) Tumaini 50) Berea 51) Soko Gachororo 52) Gachororo 53)White line 54) Highpoint 55)County offices 56)Sunrise 57) Kareme 58) Cheers 59)Seagull 60) Marbles 61) Philo1 62)Mwangaza 63) Public Primary Schools Thiririka Primary School Gachororo Primary School Kalimoni Primary School Murimani Primary School Juja Farm Primary School Karamaini Primary School Nyachaba Primary School Athi Primary SchoolPublic High Schools Mangu High School Gachororo Secondary School Kalimoni Senior SchoolTechnical Colleges Kilimambogo Technical Training CollegePublic Universities Jomo Kenyatta University of Agriculture and Technology Juja serves as the Main Headquarters to a couple of organisations such as Straight Security, a private security company that provides manned security all over Kenya, Senate Hotel, a 3 star Hotel, Glowbal TechXperts limited.
Henry Wilkinson Cookson was an English clergyman and academic, who served as Master of Peterhouse, Cambridge from 1847 until his death. He was born on 10 April 1810 at the sixth son of Thomas and Elizabeth Cookson. William Wordsworth, for whose poetry he always cherished a reverential admiration, was one of his godfathers, he was educated at Kendal Grammar School and at Sedbergh School at Peterhouse, matriculating in October 1828, graduating B. A. 1832, M. A. 1835, B. D. and D. D. 1848. His private tutors were William Hopkins, he was appointed a Fellow in 1836 and a Tutor in 1839. His pupils included Sir William Thomson, he was Proctor in 1842. In 1847 he succeeded William Hodgson as Master of Peterhouse, as Rector of Glaston until 1867, when this rectory was by the new college statutes detached from the headship with which it had hitherto been combined, he was elected Vice-Chancellor on five occasions, was President of the Cambridge Philosophical Society 1865–66. In 1867 he declined it. In 1855 he married Emily Valence, elder daughter of Gilbert Ainslie, Master of Pembroke College, by whom he had one daughter.
He died, on 30 September 1876, in Peterhouse Lodge. This article incorporates text from a publication now in the public domain: Adolphus William. "Cookson, Henry Wilkinson". In Stephen, Leslie. Dictionary of National Biography. 12. London: Smith, Elder & Co. pp. 105–106