Wilkinson Microwave Anisotropy Probe
The Wilkinson Microwave Anisotropy Probe (WMAP) is a NASA Explorer mission that launched June 2001 to make fundamental measurements of cosmology -- the study of the properties of our universe as a whole. WMAP has been stunningly successful, producing our new Standard Model of Cosmology. WMAP's data stream has ended. Full analysis of the data is now complete. Publications have been submitted as of 12/20/2012.
WMAP TEAM RECEIVES THE 2012 GRUBER COSMOLOGY PRIZE
"The Gruber Foundation proudly presents the 2012 Cosmology Prize to Charles Bennett and the Wilkinson Microwave Anisotropy Probe team for their exquisite measurements of anisotropies in the relic radiation from the Big Bang---the Cosmic Microwave Background. These measurements have helped to secure rigorous constraints on the origin, content, age, and geometry of the Universe, transforming our current paradigm of structure formation from appealing scenario into precise science."
Other Members of the WMAP team are:
Chris Barnes, Rachel Bean, Olivier Doré, Joanna Dunkley, Benjamin M. Gold, Michael Greason, Mark Halpern, Robert Hill, Gary F. Hinshaw, Norman Jarosik, Alan Kogut, Eiichiro Komatsu, David Larson, Michele Limon, Stephan S. Meyer, Michael R. Nolta, Nils Odegard, Lyman Page, Hiranya V. Peiris, Kendrick Smith, David N. Spergel, Greg S. Tucker, Licia Verde, Janet L. Weiland, Edward Wollack, and Edward L. (Ned) Wright.
For more information about the prize visit: 2012 Gruber Cosmology Prize Press Release
WMAP's Top Ten
The WMAP science team has…
... has put the "precision" in "precision cosmology" by reducing the allowed volume of cosmological parameters by a factor in excess of 68,000. The three most highly cited physics and astronomy papers published in the new millennium are WMAP scientific papers--- reflecting WMAP's enormous impact.
…mapped the pattern of tiny fluctuations in the Cosmic Microwave Background (CMB) radiation (the oldest light in the universe) and produced the first fine-resolution (0.2 degree) full-sky map of the microwave sky.
…determined the universe to be 13.77 billion years old to within a half percent.
…nailed down the curvature of space to within 0.4% of "flat" Euclidean.
…determined that ordinary atoms (also called baryons) make up only 4.6% of the universe.
…completed a census of the universe and finds that dark matter (matter not made up of atoms) is 24.0%
…determined that dark energy, in the form of a cosmological constant, makes up 71.4% of the universe, causing the expansion rate of the universe to speed up. - "Lingering doubts about the existence of dark energy and the composition of the universe dissolved when the WMAP satellite took the most detailed picture ever of the cosmic microwave background (CMB)." - Science Magazine 2003, "Breakthrough of the Year" article
… mapped the polarization of the microwave radiation over the full sky and discovered that the universe was reionized earlier than previously believed. - "WMAP scores on large-scale structure. By measuring the polarization in the CMB it is possible to look at the amplitude of the fluctuations of density in the universe that produced the first galaxies. That is a real breakthrough in our understanding of the origin of structure." - ScienceWatch: "What's Hot in Physics", Simon Mitton, Mar./Apr. 2008.
…detected that the amplitude of the variations in the density of the universe on big scales is slightly larger than smaller scales. This, along with other results, supports "inflation", the idea is that the universe underwent a dramatic period of expansion, growing by more than a trillion trillion fold in less than a trillionth of a trillionth of a second. Tiny fluctuations were generated during this expansion that eventually grew to form galaxies.
… determined that the distribution of these fluctuations follows a bell curve with the same properties across the sky, and that there are equal numbers of hot and cold spots in the map. The simplest version of the inflation idea predicted these properties and remarkably, WMAP’s precision measurement of the properties of the fluctuations has confirmed these predictions, in detail.
THE END OF THE BEGINNING
"The last word from WMAP marks the end of the beginning in our quest to understand the Universe. WMAP has brought precision to cosmology and the Universe will never be the same."
-Adam Riess, recipient of the 2011 Nobel Prize in physics
STEVEN HAWKING
"Stephen Hawking recently told New Scientist that WMAP's evidence for inflation was the most exciting development in physics during his career."
-2013 Smart Guide,New Scientist
WMAP AWARDED GRUBER PRIZE
"WMAP has had a transformative impact on the field of cosmology. It provided strong confirmation of our basic picture of the universe and added unprecedented precision. It is the benchmark for almost every other cosmological measurement and sets a very high bar for future experiments."
-Neil Turok, Director of the Perimeter Institute for Theoretical Physics
WMAP MISSION SCORES 'WORLD'S MOST CITED' IN SCIENCE PUBS
"WMAP results were among the most-cited scientific papers in the world across all scientific disciplines [in 2011], not just in physics and astronomy. It also happened in 2003, 2007 and 2009. This time WMAP captured the first, second and third spots in the rankings in a single year—a science trifecta."
- Johns Hopkins University Gazette, 2012/04/23
THE RED-HOT RESEARCH PAPERS OF 2011
"Achieving particular distinction atop the list are three reports from the Wilkinson Microwave Anisotropy Probe (WMAP), launched in 2001. ... Paper #1 in the table, delivering the "cosmological interpretations" of the WMAP seven-year data, had already been cited more than 500 times before the end of its first year of publication."
- Science Watch/ The Hottest Research of 2011 by Christopher King ----The List
"Every astronomer will remember the moment he heard the results from WMAP."
"Before the WMAP results, astronomers and physicists had put together a very implausible picture of our universe. It had a tiny amount of ordinary matter. It had a modest amount of dark matter, whatever that is. It had an overwhelming amount of dark energy, which is a strange beast. I have to confess I was very skeptical of this picture. But the WMAP results have convinced me."
"The announcement today represents a rite of passage for cosmology from speculation to precision science."
- John Bahcall of the Institute for Advanced Study in Princeton, N.J.
"WMAP is the instrument that finally allowed scientists to hear the celestial music and figure out what sort of instrument our cosmos is... WMAP has nearly perfect pitch."
"It ends a decades-long argument about the nature of the universe and confirms that our cosmos is much, much stranger than we ever imagined."
"All the arguments of the last few decades about the basic properties of the universe—its age, its expansion rate, its composition, its density—have been settled in one fell swoop."
-Science Magazine 2003, "Breakthrough of the Year" article
The precise and accurate WMAP result is "now the frame of reference for all cosmological investigations." It "dramatically shrinks the volume of parameter space that describes our universe."
-ScienceWatch: "What's Hot in Physics", Simon Mitton, Mar./Apr. 2008
"In a sentence, the observations are spectacular and the conclusions are stunning," said Brian Greene of Columbia University in New York City. "WMAP data support the notion that galaxies are nothing but quantum mechanics writ large across the sky." "To me, this is one of the marvels of the modern scientific age."
StarChild Question of the Month for July 2001
Question:
What is the shape of the universe?
Answer:
One of the most profound insights of General Relativity was the conclusion that mass caused space to curve, and objects travelling in that curved space have their paths deflected, exactly as if a force had acted on them. If space itself is curved, there are three general possibilities for the geometry of the universe. Each of these possibilites is tied to the amount of mass (and thus to the total strength of gravitation) in the universe, and each implies a different past and future for the universe.
First, let's look at shapes and curvatures for a two-dimensional surface. Mathematicians distinguish 3 qualitatively different classes of curvature, as illustrated in the following image:
The flat surface at the left is said to have zero curvature, the spherical surface is said to have positive curvature, and the saddle-shaped surface is said to have negative curvature.
The preceding is not too difficult to visualize, but General Relativity asserts that space itself (not just an object in space) can be curved, and furthermore, the space of General Relativity has 3 space-like dimensions and one time dimension, not just two as in our example above. This IS difficult to visualize! Nevertheless, it can be described mathematically by the same methods that mathematicians use to describe the 2-dimensional surfaces. So what do the three types of curvature - zero, positive, and negative -mean to the universe?
If space has negative curvature, there is insufficient mass to cause the expansion of the universe to stop. In such a case, the universe has no bounds, and will expand forever. This is called an open universe.
If space has no curvature (i.e, it is flat), there is exactly enough mass to cause the expansion to stop, but only after an infinite amount of time. Thus, the universe has no bounds and will also expand forever, but with the rate of expansion gradually approaching zero after an infinite amount of time. This is termed a flat universe or a Euclidian universe (because the usual geometry of non-curved surfaces that we learn in high school is called Euclidian geometry).
If space has positive curvature, there is more than enough mass to stop the present expansion of the universe. The universe in this case is not infinite, but it has no end (just as the area on the surface of a sphere is not infinite but there is no point on the sphere that could be called the "end" ). The expansion will eventually stop and turn into a contraction. Thus, at some point in the future the galaxies will stop receding from each other and begin approaching each other as the universe collapses on itself. This is called a closed universe.
The geometry of the universe is often expressed in terms of the "density parameter", which is defined as the ratio of the actual density of the universe to the critical density that would be required to cause the expansion to stop. Thus, if the universe is flat (contains just the amount of mass to close it) the density parameter is exactly 1, if the universe is open with negative curvature the density parameter lies between 0 and 1, and if the universe is closed with positive curvature the density parameter is greater than 1.
The density parameter determined from various methods such as calculating the number of baryons created in the big bang, counting stars in galaxies, and observing the dynamics of galaxies both near and far. With some rather large uncertainties, all methods point to the universe being open (i.e. the density parameter is less than one). But we need to remember that it is unlikely that we have detected all of the matter in the universe yet.
The current theoretical belief (because it is predicted by the theory of cosmic inflation) is that the universe is flat, with exactly the amount of mass required to stop the expansion (the corresponding average critical density that would just stop the is called the closure density). Recent observations (such as the BOOMERANG and MAXIMA cosmic microwave background radiation results, and various supernova observations) imply that the expansion of the universe is accelerating. If so, this strongly suggests that the universe is geometrically "flat".
In reality, determining the value of the density parameter and thus the ultimate fate of the universe remains one of the major unsolved problems in modern cosmology. The recently (June 30, 2001) launched MAP mission will be able to measure the value definitively within the next 5 years.
Originally posted by twhiteheadI am not suggesting that time does not exist or has not been proven to exist. I accept the concept of time regardless of it being proven or not. My statement challenged that time represents a fourth dimension. I do not believe time has been proven to be a fourth dimension. We define space in terms of three dimensions. It is only a theory that time is a fourth dimension.
Time has not been proven to exist? Did you manage to write that post instantaneously?
Originally posted by lemon limeTime is [b]not[/] the fourth dimension.
What article? Someone asked what the fourth dimension is and I said it was time.
Are you referring to what you said about a fifth dimension?
Numbering is arbitrary.
And time can be considered as a dimension.
But it is not a spatial dimension - which is what is under discussion.
Originally posted by josephwYou should add an "s"
StarChild Question of the Month for July 2001
Question:
What is the shape of the universe?
Answer:
One of the most profound insights of General Relativity was the conclusion that mass caused space to curve, and objects travelling in that curved space have their paths deflected, exactly as if a force had acted on them. If space itself is curve ...[text shortened]... 01) launched MAP mission will be able to measure the value definitively within the next 5 years.
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Originally posted by twhiteheadI assumed in his question josephw was referring to "a single frame of reference according to which the universe has a static geometry of three spatial dimensions."
This one:
http://en.m.wikipedia.org/wiki/Shape_of_the_universe
Time (or space-time) doesn't need to be considered when determining the current shape of the universe... and space is necessarily a part of that three dimensional single frame snapshot of the universe.
Originally posted by twhiteheadBut where is time itself?
How did you observe it without time?
Time itself is not observable (and thanks to the Wheeler-DeWitt equation we are OK by means of just describing the related to the one another varieties). In fact we don’t see time, all we see is the clock. When we say “This car moves”, we merely say “This car is here when the hands of your clock are here”. Instead of measuring time with our clocks, we cannot see time itself but only the hands of the clocks, which are just another physical variable. So we do not observe time itself but specific physical variables as a function of other physical variables, which we represent them As If everything is evolving in time;
By the way, what goes on beyond Planck time?
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Originally posted by twhiteheadIf space (the 3D realm in which all material objects are located and all events occur, that is) is existent, then space is indeed observable
Neither is space. We only see object in space and time. We can measure their position in space and time. Dimensions are not visible objects, they are the rulers by which we measure objects, and time is one of those rulers.
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