Thunder

Thunder is the sound caused by lightning. Depending on the distance and nature of the lightning, thunder can range from a sharp, loud crack to a long, low rumble (brontide). The sudden increase in pressure and temperature from lightning produces rapid expansion of the air surrounding and within a bolt of lightning. In turn, this expansion of air creates a sonic shock wave, similar to a sonic boom, which produces the sound of thunder, often referred to as a clap, crack, or peal of thunder.

Cause

The cause of thunder has been the subject of centuries of speculation and scientific inquiry. The first recorded theory is attributed to the Greek philosopher Aristotle in the fourth century BC, and an early speculation was that it was caused by the collision of clouds. Subsequently, numerous other theories were proposed. By the mid-19th century, the accepted theory was that lightning produced a vacuum.

In the 20th century a consensus evolved that thunder must begin with a shock wave in the air due to the sudden thermal expansion of the plasma in the lightning channel. The temperature inside the lightning channel, measured by spectral analysis, varies during its 50 μs existence, rising sharply from an initial temperature of about 20,000 K to about 30,000 K, then dropping away gradually to about 10,000 K. The average is about 20,400 K (20,100 °C; 36,300 °F). This heating causes a rapid outward expansion, impacting the surrounding cooler air at a speed faster than sound would otherwise travel. The resultant outward-moving pulse is a shock wave, similar in principle to the shock wave formed by an explosion, or at the front of a supersonic aircraft.

Saudi Arabia

Saudi Arabia (ⁱ/ˌsɔːdiː əˈreɪbiə/, ⁱ/ˌsaʊ-/), officially known as the Kingdom of Saudi Arabia (KSA), is an Arab state in Western Asia constituting the bulk of the Arabian Peninsula. With a land area of approximately 2,150,000 km² (830,000 sq mi), Saudi Arabia is geographically the second-largest state in the Arab world after Algeria. Saudi Arabia is bordered by Jordan and Iraq to the north, Kuwait to the northeast, Qatar, Bahrain, and the United Arab Emirates to the east, Oman to the southeast, and Yemen to the south. It is the only nation with both a Red Sea coast and a Persian Gulf coast, and most of its terrain consists of arid inhospitable desert or barren landforms.

The area of modern-day Saudi Arabia formerly consisted of four distinct regions: Hejaz, Najd, and parts of Eastern Arabia (Al-Ahsa) and Southern Arabia ('Asir). The Kingdom of Saudi Arabia was founded in 1932 by Ibn Saud. He united the four regions into a single state through a series of conquests beginning in 1902 with the capture of Riyadh, the ancestral home of his family, the House of Saud. The country has since been an absolute monarchy, effectively a hereditary dictatorship governed along Islamic lines. The ultra-conservative Wahhabism religious movement within Sunni Islam has been called "the predominant feature of Saudi culture", with its global spreading largely financed by the oil and gas trade. Saudi Arabia is sometimes called "the Land of the Two Holy Mosques" in reference to Al-Masjid al-Haram (in Mecca), and Al-Masjid an-Nabawi (in Medina), the two holiest places in Islam. The Kingdom has a total population of 28.7 million, of which 20 million are Saudi nationals and 8 million are foreigners.

North Thunder

North Thunder or (in Arabic: رعد الشمال) is the joint military exercises held between Saudi Arabia and Egypt on the territory of the Kingdom of Saudi Arabia with the participation of a number of Arab and Islamic countries notably the United Arab Emirates, Bahrain, Sudan, Jordan, Pakistan, and Yemen.

The goal of the exercises

Maneuvers aim to raise the technical and combat efficiency rates of combat elements of participation, and implementation of loading scheme and strategic transport of troops from their concentration areas to the load and access ports, so as to achieve the points and goals of training desired accessible, leading to higher efficiency and combat readiness rates for the implementation of joint missions between the participating States forces to face risks and challenges that target the security and stability of the region.

Maneuvers executed

Has been planned for the first maneuvers Raad north to start on February 26, 2016 for a period of two weeks northeast of King Khaled Military City in Saudi Arabia, with the participation of several military branches are artillery, tanks, and infantry, and air defense systems, naval forces.

Pakistan Aeronautical Complex

The Pakistan Aeronautical Complex, (or PAC), is a major aerospace, defence, aviation contractor, and military corporation producing aerial systems for both military and civilian usage, situated in Kamra, Attock District .

Founded in 1971 by the Pakistan Air Force (PAF), the PAC designs, develops, and build aircraft and avionics systems for the Inter–Services of the country; it also provides its services for civilian aircraft. In addition, the PAC performs local maintenance and works on the aircraft MLU systems of foreign-built military and civilian aircraft. It is solely owned by the PAF as its corporate interests and its corporate appointments are directly made by the Chief of air staff from the Air HQ of the PAF.

Mainly focusing on avionics, aviation, and high-tech electronics, the PAC also manufactures military systems for army and navy, which are listed as "valued customers". Many of these products are specially suited for the Pakistan Armed Forces needs, while others are also marketed to foreign militaries. While it collaborated with several countries corporate organizations, the PAC often jointly works with the Turkish TAI and the Chinese CATIC.