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BLACK HOLES.
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Definition, creation, theory, methods of discovery, observation & analysis.... More...
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Paper Abstract:
Definition, creation, theory, methods of discovery, observation & analysis.
Paper Introduction:
BLACK HOLES
Background
Many areas of astronomical research are inter related so that knowledge gained in one area causes a rethinking of other issues and provides evidence to solve old and new problems. One area of research that offers information useful to astronomers and physicists on many different issues is the search for black holes, an ongoing process that has been enhanced by the creation of the Hubble Space Telescope, and a central location for studying black holes is the Space Telescope Science Institute, the nerve center of the Hubble.
Black holes are theorized celestial bodies with a surface gravity so strong that nothing can escape from them, including light. If a star more massive than the Sun should undergo gravitational collapse at t
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An ongoing search inside a mountain in central Italyrecently reported the possibility that a new particle which may be a WIMPhas been found. If a star moremassive than the Sun should undergo gravitational collapse at the end ofits evolution, it will form either a white dwarf, a neutron star, or ablack hole, depending primarily on its mass. "Has a Dark Particle Come to Light?"Science. "Black Hole Hunters." Astronomy, 48-55. "Probing the Milky Way's BlackHeart." Science. There is a good deal of natural radioactivity in the rock andother materials surrounding the detectors, meaning there is a huge amountof background signals. Black holes are theorized celestial bodies with a surface gravity sostrong that nothing can escape from them, including light. "The hunt for black holes." Technolocy Review (January1, 1995), 16-17. However, the WIMPs wouldnot have collapsed because they cannot radiate photons to shed energy. WIMPS BackgroundBlack holes have been cited as one of the reasons the amount of matter inthe universe appears to be less than required to explain the gravitationalpull seen in the universe and to fulfill ideas suggested by the Big Bangtheory and the possibility of a closed universe. Iffound, it could account for some or all of the mysterious dark matter thatastronomers believe far outweighs the galaxy's glowing stars and gasclouds. It consists of nine9.7-kilogram crystals of doped sodium iodide -- a material thatscintillates, or generates a flash of light, when one of its nuclei orelectrons recoils after interacting with another particle. (May 1999). Other scientistsare examining the idea that at the very center of our galaxy, there is aninvisible black hole, and that just outside it, electrons torn from matterfalling into the black hole gyrate around magnetic field lines,broadcasting radio waves. Yet they remain elusive, their interiors forever shrouded behind a gravitational attraction from which not even light can escape (Olson 5 ). Black holes could come in a range ofsizes if they exist, from small ones formed under conditions at thebeginning of the universe to gigantic black holes that might lie at thecenter of galaxies. Related Research A recent meeting of the world's leading cosmologists in Chicagooffered a new candidate for the role of dark matter, a hypotheticalparticle called a Wimpzilla, which would be millions to trillions of timesmore massive than a Wimp. Graham, David. Olson, Steve. There are only two ways todetect black holes. Theyalso found a tremendous amount of electromagnetic radiation streaming fromthe galaxy's core and cite this as further confirmation of a black hole.Astronomers have known for decades that M87 is a weak version of a quasar,a type of galaxy emitting a display of electromagnetic energy brighter thanthe rest of the stars in the galaxy. Observations and Analysis The Johns Hopkins team is headed by Holland Ford and Richard Harms,and they benefited from the improved optics of the Hubble. Photodetectorsare used to gather the light, and the results are stored on computers foranalysis. Pierluigi Belli, a Universityof Rome physicist who is a member of the collaboration, oversees theproject called DAMA (for DArk MAtter). Other possible ways muchof the matter in the universe might be hidden have also been proposed -- itis thought that as much as 9 percent of the amount of matter needed toexplain observed gravitational phenomena is hidden in some fashion. As suchmolecules bunch up and are heated to high temperatures, x-rays are emitted,and such x-rays have been detected in eclipsing binary star systems inwhich the x-ray source is not visible. One teaminvestigating this issue was at Johns Hopkins University, where the groupstudied M87, a giant elliptical galaxy in Virgo some 5 million light-yearsaway. It recently picked up thestrongest hint so far of passing WIMPs, showing a particle countthat appears to vary with the seasons as the Earth's orbit carries it intoa galactic wind of WIMPs and then out again. The theory is that a black hole wouldcreate just such an effect as material becomes rapidly condensed and thussuperheated as it nears the hole (Graham 16-17). Some are concerned that if rare, lumberingWimpzillas make up the dark matter, then current Wimp searches would haveno hope of turning up a signal unless the universe is populated by an evenmore bizarre mixture of the two particles (Glanz "Superheavy Particles Fromthe Big Bang?"). This implies that there is a central black hole with 1 million to 2 million times the mass of the sun. If the process of collapse is nonspherical because thestar is rotating and flattened at the poles, then gravitational waves couldbe given off just before the black hole is formed; such waves would bedetectable. Onecandidate raised by scientists are called weakly interacting massiveparticles, or WIMPs. They concluded that this could only be caused by a black hole. BLACK HOLESBackground Many areas of astronomical research are inter-related so thatknowledge gained in one area causes a rethinking of other issues andprovides evidence to solve old and new problems. Works Cited Glanz, James. The core of M87 emits a huge jet of particles traveling at near lightspeed. Methods and Observations The particle found has a mass about 6 times that of the proton. The team examined images and spectra of glowing gas near the centerof the galaxy. Debris thrown off by Wimpzillas when they decay might then explainthe rare, mysterious cosmic rays that slam into Earth's atmosphere atastonishingly high energies. Thismeans they should hardly rotate at all so that the sun should encounter theWIMPs as a kind of wind (Glanz "Has a Dark Particle Come to Light?"). Astronomers have been seeing theeffects of black holes but not the objects themselves: Once considered a theorist's fancy, black holes are now thought to reside at the core of almost all large galaxies. The other way is through the interactions of the black holewith other matter. They measuredthe M87 spinning disk's size and calculated its speed by observing how thecolor of light in the rotating disk changes slightly as light approaches orrecedes from a viewer, a phenomenon called the Doppler shift. Linda Dressel was a member of the Johns Hopkins Team and isnow at Space Telescope Science Institute where she takes spectra ofgalactic cores with the Space Telescope Imaging spectrograph. It is thus necessary to sort any WIMP signal fromthis noise, and to do this, the DAMA researchers look for a subtle seasonalvariation in the scintillation counts. Related Research Other researchers are also searching for black holes and inferringtheir existence based on observations of their effects. Goals The Hubble Space Telescope has provided a new opportunity for thoseseeking black holes because of its superior resolution, allowingastronomers to extend their search to far greater distances. Dressel has also studiedother central black holes with around 1 million solar masses and hasraised the question of whether every galaxy has a black hole (Olson 5 -51). One area of research thatoffers information useful to astronomers and physicists on many differentissues is the search for black holes, an ongoing process that has beenenhanced by the creation of the Hubble Space Telescope, and a centrallocation for studying black holes is the Space Telescope Science Institute,the nerve center of the Hubble. "Superheavy Particles From the BigBang?" Science. (October 9, 1998). Schilling, Govert. Such particles could support the effort toexplain all the forces of nature in a single framework through the so-called grand unified theory (GUT), put forth in 199 by John Ellis of CERNin Geneva, Switzerland, Dimitri Nanopoulos of Texas A&M University, andothers. Scientists have been mapping this radio emissionwith the Very Long Baseline Array, a system of linked telescopes that spansNorth America, and they have found that the emitting region is drasticallyelongated, suggesting that the black hole is somehow shooting jets ofmaterial out of the plane of the galaxy (Schilling). Researchers have set up WIMP detectors in underground laboratoriesaround the world. They foundthat the disk's speed rose steadily to as high as one million miles an hoursome 5 million light-years from the center, and they then estimated thatthe mass of a gravity source required to hold such a massive disk togetherat such high velocities would have to be 2 to 3 billion times that of thesun. (January 1, 1999). Glanz, James. When the galaxy formed from acollapsing cloud of gas, the cloud's rotation was amplified so that thevisible matter of the galaxy now spins rapidly, carrying the sun around thegalactic center at some 22 kilometers per second. One such collaboration has been working at the Gran SassoLaboratory in Italy's Apennine Mountains. (February 19, 1999). Black holes have been described for some time, and manypeople may believe many have been found. Detecting a WIMP is a matter ofsetting a trap and waiting, and DAMA is such a trap. Herobservations show gas swirling around the center of NGC 3998 at 9 , miles per hour. If the black hole is formed in a binary star system, forinstance, gas from the normal star might flow toward the black hole, itsmolecules increasing in speed to near the speed of light.
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