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The Sun is the star at the center of the Solar System. It is a nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy mainly as light and infrared radiation. It is by far the most important source of energy for life on Earth. Its diameter is about 1.39 million kilometres (864,000 miles), or 109 times that of Earth, and its mass is about 330,000 times that of Earth. It accounts for about 99.86% of the total mass of the Solar System.
Roughly three quarters of the Sun's mass consists of hydrogen (~73%); the rest is mostly helium (~25%), with much smaller quantities of heavier elements, including oxygen, carbon, neon, and iron.The Sun is a G-type main-sequence star (G2V) based on its spectral class. As such, it is informally and not completely accurately referred to as a yellow dwarf (its light is closer to white than yellow). It formed approximately 4.6 billion years ago from the gravitational collapse of matter within a region of a large molecular cloud. Most of this matter gathered in the center, whereas the rest flattened into an orbiting disk that became the Solar System. The central mass became so hot and dense that it eventually initiated nuclear fusion in its core. It is thought that almost all stars form by this process.
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Irbid (Arabic: إرْبِد), known in ancient times as Arabella or Arbela (Άρβηλα in Ancient Greek), is the capital and largest city of the Irbid Governorate. It also has the second largest metropolitan population in Jordan after Amman, with a population of around 1,911,600. Irbid is located about 70 kilometres (43 mi) north of Amman on the northern ridge of the Gilead, equidistant from Pella, Beit Ras (Capitolias), and Um Qais, and approximately 20 kilometres (12 mi) south of the Syrian border.
Irbid was built on successive Early Bronze Age settlements and was possibly the biblical Beth Arbel and the Arbila of the Decapolis, a Hellenistic league of the 1st century BCE through the 2nd century CE.