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... Science Frontiers ONLINE No. 103: Jan-Feb 1996 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Einstein's nemesis: di herculis DI Herculis is an 8th-magnitude eclipsing binary about 2,000 light years from earth. These two young blue stars are very close -- only one fifth the distance from earth to our sun. They orbit about a common center of gravity every 10.55 days. So far, no problem! The puzzle is that, as the two stars swing around one another, the axis of their orbit rotates or precesses too slowly. General relativity predicts a precession of 4.27 /century, but for DI Herculis the rate is only 1.05 /century. This does not sound like a figure large enough to get excited about, but it deeply troubles astronomers. D. Popper, an astronomer at UCLA, says: "The observations are pretty clear. I don't think there's any question there's a discrepancy and, frankly, it is an important one and it's unresolved." Accentuating the challenge to general relativity is the discovery that a second eclipsing binary, AC Camelopardalis, also violates general relativity in the same way. It seems that wherever gravitational fields are extremely strong and space-time, therefore, highly distorted, general relativity fails. Ironically, it was a very similar sort of astronomical observation that helped make general relativity a pillar of the scientific edifice early in the 20th. century. The orbit of Mercury precesses a ...
Terms matched: 1 - Score: 49 - 15 May 2017 - URL: /sf103/sf103a04.htm
... a huge forest but hardly disturbed the ground. Recently, Mirror Matter has been invoked to explain the ups and downs of terrestrial biodiversity. R. Foot and Z. Silagadze propose that the 26-millionyear periodicity in terrestrial extinctions -- claimed to be present in the fossil record -- is due to a solar-system planet made of Mirror Matter (and therefore invisible). This postulated planet has a period of 26-million years and regularly gravitationally jostles the Oort Cloud of comets on the periphery of the solar system. These jolts unleash torrents of devastating comets upon the inner solar system every 26-million years, thereby blasting the earth and its sensitive biological cargo. This supposed Mirror-Matter planet happens to be the conceptual double of a Normal-Matter, hypothetical planet named Nemesis, which was proposed in the 1980s to account for the same periodical extinctions in the fossil record. However, diligent searches did not locate Nemesis. Of course, if Nemesis were made of Mirror Matter, as now proposed, it would have escaped telescopic detection then and would still elude our telescopes today! (Schilling, Govert; "Through the Looking Glass," New Scientist, p. 16, April 28, 2001.) Comment. Not only is a crater missing at the Tunguska site, but no one has been able to positively identify the immense impact crater that we suppose must have been excavated when untold numbers of tektites rained down upon Australia, Southeast Asia, and the Indian Ocean about 800,000 years ago. See item under GEOLOGY. From Science Frontiers # ...
Terms matched: 1 - Score: 34 - 15 May 2017 - URL: /sf136/sf136p03.htm
... a grayish ice cube, fizzes at its edges, and soon wastes away to a puddle of water? If you wish, you can accelerate the substance's demise by touching a match to it; it is packed with potential energy. The substance is methane hydrate, and it is found in prodigious quantities in oceanic sediments. Each cubic centimeter of methane hydrate contains about 160 cubic centimeters of methane at standard conditions; it is a concentrated source of natural gas. In fact, methane hydrate deposits in the world's oceans hold twice as much carbon as all the coal, oil, and gas reserves on land! But methane hydrate may be much more than a future fuel source; it may have been humanity's savior in eons gone by; it may be our future nemesis. You see, methane hydrate is very unstable; changes of temperature or pressure on a global basis can trigger the release of immense volumes of this greenhouse gas from oceanic deposits. For example, when the Ice Ages lowered ocean levels by locking up water in the advancing ice caps, pressures on ocean-bottom methane hydrate lessened and, according to some speculators, released enough gas so that the increased greenhouse heating turned back the Ice Ages. (Was Gaia at work here?) On the other hand, if present human activities are truly stoking the greenhouse effect, ocean temperatures should rise, possibly destabilizing methane hydrate deposits and thereby aggravating the greenhouse effect. Such positive feedback could cook the biosphere. (Anonymous; "Did Methane Curb Ice Ages," New Scientist, p. ...
Terms matched: 1 - Score: 15 - 15 May 2017 - URL: /sf077/sf077g12.htm
... Science Frontiers ONLINE No. 103: Jan-Feb 1996 Other pages Home Page Science Frontiers Online All Issues Last Issue Next Issue Sourcebook Project Sourcebook Subjects Contents Archaeology A REMARKABLE MAYAN SUSPENSION BRIDGE Did irish monks build this new england chamber circa 700 ad? Two probable frauds Astronomy Einstein's nemesis: di herculis A BRIEF HISTORY OF QUANTIZED TIME Biology Passenger pigeons not extinct! I HISS THEREFORE I AM Geology Target: south america Fossil mantle plume under south america But what about the hawaiian volcanic chain? Geophysics A SUBTERRANEAN TROMBONE Anomalous radar echoes and visual phenomenon "BLUE JETS" EMITTED UPWARD FROM TOPS OF THUNDERCLOUDS Stythe = choke damp Psychology Seeing is feeling Mathematics How to find a piece of pi ...
Terms matched: 1 - Score: 15 - 15 May 2017 - URL: /sf103/index.htm
... million-year periodicities of three terrestrial phenomena: Biological extinctions in the fossil record, Magnetic field reversals, and Terrestrial-crater ages. Could there be a connection between the clumped meteorite ages and these terrestrial phenomena? Perlmutter and Muller propose that all of these phenomena are the consequence of periodic storms of comets that invade the inner solar system from the direction of the Oort Cloud of comets that purportedly hovers at the fringe of the solar system. These comets not only devastate the earth but also collide with the asteroids, knocking off those bits and pieces we call meteorites. (Anonymous; "Do Meteorite Ages Tell of Comet Storms?" Astronomy, 17:12, January 1989.) Comment. Unanswered above is the question of why comet storms should be periodic. One hypothesis is that Nemesis, the so-called Death Star, a dark companion of our sun, lurks out there, periodically nudging the Oort Cloud of comets, causing it to release some of its comets. From Science Frontiers #62, MAR-APR 1989 . 1989-2000 William R. Corliss ...
Terms matched: 1 - Score: 13 - 15 May 2017 - URL: /sf062/sf062a05.htm
