Vega vs Sheffield

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Vega is the brightest star in the northern constellation of Lyra. It has the Bayer designation α Lyrae, which is Latinised to Alpha Lyrae and abbreviated Alpha Lyr or α Lyr. This star is relatively close at only 25 light-years from the Sun, and, together with Arcturus and Sirius, one of the most luminous stars in the Sun's neighborhood. It is the fifth-brightest star in the night sky, and the second-brightest star in the northern celestial hemisphere, after Arcturus. Vega has been extensively studied by astronomers, leading it to be termed "arguably the next most important star in the sky after the Sun". Vega was the northern pole star around 12,000 BC and will be so again around the year 13,727, when its declination will be +86° 14′. Vega was the first star other than the Sun to be photographed and the first to have its spectrum recorded. It was one of the first stars whose distance was estimated through parallax measurements. Vega has functioned as the baseline for calibrating the photometric brightness scale and was one of the stars used to define the zero point for the UBV photometric system.

Vega is only about a tenth of the age of the Sun, but since it is 2.1 times as massive, its expected lifetime is also one tenth of that of the Sun; both stars are at present approaching the midpoint of their life expectancies. Vega has an unusually low abundance of the elements with a higher atomic number than that of helium. Vega is also a variable star that varies slightly in brightness. It is rotating rapidly with a velocity of 236 km/s at the equator. This causes the equator to bulge outward due to centrifugal effects, and, as a result, there is a variation of temperature across the star's photosphere that reaches a maximum at the poles. From Earth, Vega is observed from the direction of one of these poles.Based on an observed excess emission of infrared radiation, Vega appears to have a circumstellar disk of dust. This dust is likely to be the result of collisions between objects in an orbiting debris disk, which is analogous to the Kuiper belt in the Solar System. Stars that display an infrared excess due to dust emission are termed Vega-like stars.

Source: Wikipedia

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Sheffield is a city and metropolitan borough in South Yorkshire, England. The name derives from the River Sheaf which runs through the city. Historically part of the West Riding of Yorkshire, with some southern suburbs annexed from Derbyshire, the city has grown from its largely industrial roots to encompass a wider economic base. The population of the City of Sheffield is 584,853 (mid-2019 est.) and it is one of the eight largest regional English cities that make up the Core Cities Group. Sheffield is the second-largest city in the Yorkshire and the Humber region and the third-largest English district by population. The metropolitan population of The city of Sheffield is 1,569,000.The city is in the eastern foothills of the Pennines, and the valleys of the River Don and its four tributaries, the Loxley, the Porter Brook, the Rivelin and the Sheaf. Sixty-one per cent of Sheffield's entire area is green space, and a third of the city lies within the Peak District national park. There are more than 250 parks, woodlands and gardens in the city, which is estimated to contain around 4.5 million trees.Sheffield played a crucial role in the Industrial Revolution, with many significant inventions and technologies having developed in the city.

In the 19th century, the city saw a huge expansion of its traditional cutlery trade, when stainless steel and crucible steel were developed locally, fuelling an almost tenfold increase in the population. Sheffield received its municipal charter in 1843, becoming the City of Sheffield in 1893. International competition in iron and steel caused a decline in these industries in the 1970s and 1980s, coinciding with the collapse of coal mining in the area. The 21st century has seen extensive redevelopment in Sheffield, along with other British cities. Sheffield's gross value added (GVA) has increased by 60% since 1997, standing at £11.3 billion in 2015. The economy has experienced steady growth averaging around 5% annually, greater than that of the broader region of Yorkshire and the Humber.The city has a long sporting heritage and is home to both the world's oldest football club, Sheffield F.C., and the world's oldest football ground, Sandygate. Games between the two professional clubs, Sheffield United and Sheffield Wednesday, are known as the Steel City derby. The city is also home to the World Snooker Championship and the Sheffield Steelers, the UK's first professional ice hockey team.

Source: Wikipedia