 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
Einstein May Have Been Right After All
Baltimore - Feb 24, 2004 The good news from NASA's Hubble Space Telescope is that Einstein was right--maybe. A strange form of energy called "dark energy" is looking a little more like the repulsive force that Einstein theorized in an attempt to balance the universe against its own gravity. Even if Einstein turns out to be wrong, the universe's dark energy probably won't destroy the universe any sooner than about 30 billion years from now, say Hubble researchers. "Right now we're about twice as confident than before that Einstein's cosmological constant is real, or at least dark energy does not appear to be changing fast enough (if at all) to cause an end to the universe anytime soon," says Adam Riess of the Space Telescope Science Institute, Baltimore. Riess used Hubble to find nature's own "weapons of mass destruction" -- very distant supernovae that exploded when the universe was less than half its current age. The apparent brightness of a certain type of supernova gives cosmologists a way to measure the expansion rate of the universe at different times in the past. Riess and his team joined efforts with the Great Observatories Origins Deep Survey (GOODS) program, the largest deep galaxy survey attempted by Hubble to date, to turn the Space Telescope into a supernova search engine on an unprecedented scale. In the process, they discovered 42 new supernovae in the GOODS area, including 6 of the 7 most distant known. Cosmologists understand almost nothing about dark energy even though it appears to comprise about 70 percent of the universe. They are desperately seeking to uncover its two most fundamental properties: its strength and its permanence. In a paper to be published in the Astrophysical Journal, Riess and his collaborators have made the first meaningful measurement of the second property, its permanence. Currently, there are two leading interpretations for the dark energy, as well as many more exotic possibilities. It could be an energy percolating from empty space as Einstein's theorized "cosmological constant," an interpretation which predicts that dark energy is unchanging and of a prescribed strength. An alternative possibility is that dark energy is associated with a changing energy field dubbed "quintessence." This field would be causing the current acceleration -- a milder version of the inflationary episode from which the early universe emerged. When astronomers first realized the universe was accelerating, the conventional wisdom was that it would expand forever. However, until we better understand the nature of dark energy--its properties--other scenarios for the fate of the universe are possible. If the repulsion from dark energy is or becomes stronger than Einstein's prediction, the universe may be torn apart by a future "Big Rip," during which the universe expands so violently that first the galaxies, then the stars, then planets, and finally atoms come unglued in a catastrophic end of time. Currently this idea is very speculative, but being pursued by theorists. At the other extreme, a variable dark energy might fade away and then flip in force such that it pulls the universe together rather then pushing it apart. This would lead to a "big crunch" where the universe ultimately implodes. "This looks like the least likely scenario at present," says Riess. Understanding dark energy and determining the universe's ultimate fate will require further observations. Hubble and future space telescopes capable of looking more than halfway across the universe will be needed to achieve the necessary precision. The determination of the properties of dark energy has become the key goal of astronomy and physics today. Community Email This Article Comment On This Article Related Links The Space Telescope Science Institute SpaceDaily Search SpaceDaily Subscribe To SpaceDaily Express Nuclear Space Technology at Space-Travel.com
JHU-STScI Team Maps Dark Matter In Startling Detail
Baltimore MD (SPX) Dec 12, 2005Clues revealed by the recently sharpened view of the Hubble Space Telescope have allowed astronomers to map the location of invisible "dark matter" in unprecedented detail in two very young galaxy clusters.
--------------------------------------------------------- It's new. And it's downright terrific! Celestron's CPC Schmidt-Cassegrain telescope is the scope you've been waiting for! It offers new alignment technology, advanced engineering, and bold new design at a new, low price! In fact, Celestron's Professional Computerized (CPC) scope with revolutionary SkyAlign Alignment Technology redefines everything that amateur astronomers are looking for. It offers quick and simple alignment, GPS technology, unsurpassed optical quality, ease of use, advanced ergonomics, enhanced computerization and, most important, affordability. Want to view M-31 tonight? One button takes you there!
Shop for telescopes online at Telescopes.com! today!
|
|
|
| The content herein, unless otherwise known to be public domain, are Copyright 1995-2006 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA PortalReports are copyright European Space Agency. All NASA sourced material is public domain. Additionalcopyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement |
