- Dagestan (/ˌdæɡɪˈstæn, -ˈstɑːn/ DAG-ə-STA(H)N; Russian: Дагестан; IPA: [dəɡʲɪˈstan]), officially the Republic of Dagestan, is a republic of Russia situated in the North Caucasus of Eastern Europe, along the Caspian Sea. It is located north of the Greater Caucasus, and is a part of the North Caucasian Federal District. The republic is the southernmost tip of Russia, sharing land borders with the countries of Azerbaijan and Georgia to the south and southwest, the Russian republics of Chechnya and Kalmykia to the west and north, and with Stavropol Krai to the northwest. Makhachkala is the republic’s capital and largest city; other major cities are Derbent, Kizlyar, Izberbash, Kaspiysk, and Buynaksk.
- Speed of light (Wikipedia)
The speed of light in vacuum, commonly denoted c, is a universal physical constant that is important in many areas of physics. The speed of light c is exactly equal to 299,792,458 metres per second (approximately 300,000 kilometres per second; 186,000 miles per second; 671 million miles per hour). According to the special theory of relativity, c is the upper limit for the speed at which conventional matter or energy (and thus any signal carrying information) can travel through space.