String Revival.

• Autores: Govert Schilling
• Localización: Scientific American, ISSN 0036-8733, Vol. 292, Nº. 2, 2005, págs. 25-25
• Idioma: inglés
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• Resumen

  • The article focuses on the possible connection between cosmic strings and lensing effects. Cosmic strings are hypothetical one-dimensional defects in the fabric of spacetime. A U.S.-Ukrainian team of astronomers led by Rudolph E. Schild of the Harvard-Smithsonian Center for Astrophysics now claims that the mysterious behavior of a double quasar near the Big Dipper can best be explained by an intervening loop of cosmic string. The image of the quasar is being split in two by the gravity of a massive galaxy in the line of sight. In the mid-1990s, however, the two images winked synchronously--the brightnesses of both rose and fell together several times over a year. In the August 2004 Astronomy and Astrophysics, Schild and his colleagues show that all possible explanations for this behavior fail, except for gravitational lensing by a small loop of cosmic string close to our own Milky Way galaxy. The moving cosmic string would have acted as an additional gravitational lens, affecting both quasar images simultaneously. Meanwhile a Russian-Italian team found a much stronger cosmic string candidate in the constellation Corvus: a galaxy split into two uncannily similar and completely undistorted images. INSET: COSMIC STRINGS FROM SUPERSTRINGS.