And is it more light, or more ionization that can be understood by the apparent light and light sources?
On Sun, Jul 13, 2014 at 3:19 PM, Axil Axil <[email protected]> wrote: > Rest easy Harry > > > The article itself is confused. Whoever wrote the article had its premise > backward. > > > > > On Sat, Jul 12, 2014 at 10:27 PM, H Veeder <[email protected]> wrote: > >> >> >> >> On Sat, Jul 12, 2014 at 7:21 PM, Axil Axil <[email protected]> wrote: >> >>> Regarding the title: 400 percent less light in universe than predicted >>> >>> This article and the title are not well written. >>> >>> The title should read that there are missing light *sources* not XUV >>> light. That is, the is more light produced than there are light sources. >>> >>> [Snip] >>> >>> “It’s as if you’re in a big, brightly lit room, but you look around and >>> see only a few 40-watt lightbulbs,” >>> >>> [EndSnip] >>> >>> There are less 40-watt light bulbs than would be expected for the amount >>> of XUV light produced. These bulbs are light sources. There is too much >>> light than the light sources can produce. >>> >>> >>> >> >> Oh, my mistake, so the subject header should say "400 percent more light >> in universe than predicted" >> >> Harry >> >> >> >>> On Sat, Jul 12, 2014 at 7:03 PM, H Veeder <[email protected]> wrote: >>> >>>> CU-Boulder instrument onboard Hubble reveals the universe is ‘missing’ >>>> light >>>> >>>> http://tinyurl.com/qzs4rjo >>>> >>>> July 9, 2014 • >>>> >>>> Something is amiss in the universe. There appears to be an enormous >>>> deficit of ultraviolet light in the cosmic budget. >>>> >>>> Observations made by the Cosmic Origins Spectrograph, a $70 million >>>> instrument designed by the University of Colorado Boulder and installed on >>>> the Hubble Space Telescope, have revealed that the universe is “missing” a >>>> large amount of light. >>>> >>>> “It’s as if you’re in a big, brightly lit room, but you look around and >>>> see only a few 40-watt lightbulbs,” said the Carnegie Institution for >>>> Science’s Juna Kollmeier, lead author of a new study on the missing light >>>> published in The Astrophysical Journal Letters. “Where is all that light >>>> coming from? It’s missing from our census.” >>>> >>>> The research team—which includes Benjamin Oppenheimer and Charles >>>> Danforth of CU-Boulder’s Center for Astrophysics and Space >>>> Astronomy—analyzed the tendrils of hydrogen that bridge the vast reaches of >>>> empty space between galaxies. When hydrogen atoms are struck by highly >>>> energetic ultraviolet light, they are transformed from electrically neutral >>>> atoms to charged ions. >>>> >>>> The astronomers were surprised when they found far more hydrogen ions >>>> than could be explained with the known ultraviolet light in the universe, >>>> which comes primarily from quasars. The difference is a stunning 400 >>>> percent. >>>> >>>> Strangely, this mismatch only appears in the nearby, relatively >>>> well-studied cosmos. When telescopes focus on galaxies billions of light >>>> years away—which shows astronomers what was happening when the universe was >>>> young—everything seems to add up. The fact that the accounting of light >>>> needed to ionize hydrogen works in the early universe but falls apart >>>> locally has scientists puzzled. >>>> >>>> The mismatch emerged from comparing supercomputer simulations of >>>> intergalactic gas to the most recent analysis of observations from the >>>> Cosmic Origins Spectrograph. >>>> >>>> “The simulations fit the data beautifully in the early universe, and >>>> they fit the local data beautifully if we’re allowed to assume that this >>>> extra light is really there,” said CU-Boulder’s Oppenheimer. “It’s possible >>>> the simulations do not reflect reality, which by itself would be a >>>> surprise, because intergalactic hydrogen is the component of the universe >>>> that we think we understand the best.” >>>> >>>> The type of light that is energetic enough to turn neutral hydrogen >>>> into hydrogen ions is called “ionizing photons” and is known to come from >>>> only two sources in the universe: quasars, which are powered by hot gas >>>> falling onto supermassive black holes over a million times the mass of the >>>> sun, and the hottest young stars. Observations indicate that the ionizing >>>> photons from young stars are almost always absorbed by gas in their host >>>> galaxy, so they never escape to affect intergalactic hydrogen. But the >>>> number of known quasars is far lower than needed to produce the amount of >>>> light necessary to create the quantity of hydrogen ions measured by the >>>> research team. >>>> >>>> >>>> “If we count up the known sources of ultraviolet ionizing photons, we >>>> come up five times too short,” Oppenheimer said. “We are missing 80 percent >>>> of the ionizing photons, and the question is where are they coming from? >>>> The most fascinating possibility is that an exotic new source, not quasars >>>> or galaxies, is responsible for the missing photons.” >>>> >>>> For example, the mysterious dark matter, which holds galaxies together >>>> but has never been seen directly, could itself decay and ultimately be >>>> responsible for this extra light. >>>> >>>> “The great thing about a 400 percent discrepancy is that you know >>>> something is really wrong,” said co-author David Weinberg of Ohio State >>>> University. “We still don't know for sure what it is, but at least one >>>> thing we thought we knew about the present day universe isn’t true.” >>>> >>>> Other co-authors on the study are Francesco Haardt of the Università >>>> dell’Insubria, Romeel Davé of the University of the Western Cape, Mark >>>> Fardal of University of Massachusetts Amherst, Piero Madau of the >>>> University of California, Santa Cruz, Amanda Ford of the University of >>>> Arizona, Molly Peeples of the Space Telescope Science Institute, and Joseph >>>> McEwen of Ohio State University. >>>> >>>> The study was funded in part by NASA, the National Science Foundation >>>> and the Ahmanson Foundation. >>>> >>> >>> >> >
