GRB 970508 was a gamma-ray burst (GRB) detected on May 8, 1997, at 21:42 UTC. A gamma-ray burst is a highly luminous flash of gamma rays, the most energetic form of electromagnetic radiation, which is often followed by a longer-lived "afterglow" emitting at longer wavelengths (X-ray, ultraviolet, optical, infrared, and radio). GRB 970508 was detected by the Gamma Ray Burst Monitor on the Italian–Dutch X-ray astronomy satellite BeppoSAX. Astronomer Mark Metzger determined that GRB 970508 occurred at least 6 billion light years from Earth; this was the first measurement of the distance to a gamma-ray burst. Until this burst, astronomers had not reached a consensus regarding how far away GRBs occur from Earth. Some supported the idea that GRBs occur within the Milky Way, but are visibly faint because they are not highly energetic. Others concluded that GRBs occur in other galaxies at cosmological distances and are extremely energetic. Although the possibility of multiple types of GRBs meant that the two theories were not mutually exclusive, the distance measurement unequivocally placed the source of the GRB outside the Milky Way, effectively ending the debate. GRB 970508 was also the first burst with an observed radio frequency afterglow.
Read the rest of this article: <http://en.wikipedia.org/wiki/GRB_970508> _______________________________ Today's selected anniversaries: 1782: Running out of medical supplies to combat the disease scurvy, British troops surrendered to an allied Franco-Spanish force, ending the latter's invasion of the Island of Minorca in the Mediterranean Sea. <http://en.wikipedia.org/wiki/Invasion_of_Minorca%2C_1781> 1783: The first of five strong earthquakes hit the region of Calabria in present-day southern Italy, killing more than 32,000 people over a period of nearly two months. <http://en.wikipedia.org/wiki/1783_Calabrian_earthquakes> 1862: Domnitor Alexander John Cuza merged his two principalities, Wallachia and Moldavia, to form the Danubian Principalities. <http://en.wikipedia.org/wiki/Alexander_John_Cuza> 1885: Leopold II of Belgium established the Congo Free State as his personal possession in Africa through his organization International African Association and his private army, the Force Publique. <http://en.wikipedia.org/wiki/Congo_Free_State> 1917: The U.S. Congress passed the Immigration Act of 1917 with an overwhelming majority, overriding U.S. President Woodrow Wilson's veto, banning, among others, immigration from nearly all of South and Southeast Asia. <http://en.wikipedia.org/wiki/Immigration_Act_of_1917> 1958: A Mark 15 nuclear bomb now known as the Tybee Bomb disappeared off the shores of Tybee Island, Georgia, U.S. after it was jettisoned during a practice exercise when the bomber carrying it collided in midair with a fighter plane. <http://en.wikipedia.org/wiki/Tybee_Island_B-47_crash> _____________________________ Wiktionary's word of the day: affront (v): 1. To insult intentionally, especially openly; to offend purposefully. 2. To meet defiantly; to confront. 3. (obsolete) To meet or encounter face to face <http://en.wiktionary.org/wiki/affront> ___________________________ Wikiquote quote of the day: All progress has resulted from people who took unpopular positions. All change is the result of a change in the contemporary state of mind. Don't be afraid of being out of tune with your environment, and above all pray God that you are not afraid to live, to live hard and fast. To my way of thinking it is not the years in your life but the life in your years that count in the long run. You'll have more fun, you'll do more and you'll get more, you'll give more satisfaction the more you know, the more you have worked, and the more you have lived. For yours is a great adventure at a stirring time in the annals of men. --Adlai Stevenson <http://en.wikiquote.org/wiki/Adlai_Stevenson> _______________________________________________ Wikipedia Daily Article mailing list. To unsubscribe, visit: https://lists.wikimedia.org/mailman/listinfo/daily-article-l Questions or comments? Contact [email protected]
