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Topic: Missing mass problem

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	Dark energy - Wikipedia, the free encyclopedia
		At this mass, the white dwarf is unstable to thermonuclear runaway and explodes as a type Ia supernova with a characteristic brightness.
		Scalar fields are predicted by the standard model and string theory, but an analogous problem to the cosmological constant problem (or the problem of constructing models of cosmic inflation) occurs: renormalization theory predicts that scalar fields should acquire large masses.
		By 1998, the missing mass problem of big bang nucleosynthesis and large scale structure was established, and some cosmologists had started to theorize that there was an additional component to our universe, with properties very similar to dark energy.
	en.wikipedia.org /wiki/Dark_Energy (2754 words)

	Dark matter - Wikipedia, the free encyclopedia
		Determining the nature of this missing mass is one of the most important problems in modern cosmology and particle physics.
		Zwicky estimated the total amount of mass in a cluster of galaxies, the Coma Cluster, based on the motions of the galaxies near the edge of the cluster.
		Experimentally, however, the total kinetic energy is found to be much greater: in particular, assuming the gravitational mass is due to only the visible matter of the galaxy, stars far from the center of galaxies have much higher velocities than predicted by the virial theorem.
	en.wikipedia.org /wiki/Missing_mass (3444 words)

	The Mass Contained in Clusters (Site not responding. Last check: 2007-10-23)
		They must have masses of this size to explain how they are held together by gravity, but only about 1/10 of this mass can be identified with matter that is emitting visible light.
		This is known as the `missing mass problem'.
		The hot X-ray gas is estimated have a mass comparable to the visible matter of the galaxies in such clusters, but this is still far too little matter (by a factor of 5 to 10) to account for the gravitational forces that are holding the clusters together.
	csep10.phys.utk.edu /astr162/lect/gclusters/masses.html (249 words)

	Mass and Energy (Site not responding. Last check: 2007-10-23)
		Since the strength of the ZPE and the size of the damping constant are two of the key factors that determine the mass of the point particle, the simultaneous increase in both these factors means that the mass of the atomic particle measured in the atomic environment will also increase.
		Other work indicates that mass measured macroscopically such as those in deflection experiments, depends on the total energy of the system which remains unchanged as the ZPE increases, whereas the mass measured in an atomic environment is dependent upon the strength of the ZPE.
		Since, as Dicke points out, “the inertial mass is given by the energy of the system”, it seems that macroscopic, or inertial, means of measurement are measuring a quantity that is related to the total energy of the system.
	www.setterfield.org /MassandEnergy.htm (5679 words)

	Examples of LBT Science
		Indeed the Palomar 200-inch telescope was originally built to address this problem and to determine the value of Hubble's constant (the proportionality between distance and velocity which determines the age of the universe) and of the deceleration parameter (which measures the amount of matter or energy in the universe).
		Also connected with these questions is the problem of the origin of the chemical elements which, apart from hydrogen and helium, were formed almost entirely after matter began to condense into discrete objects such as galaxies and stars.
		The LBT will play a major role in solving these problems, which in essence address the questions of how the material content of the universe evolved from the postulated uniform distribution of the "hot big bang" to the current distribution of galaxies, stars and planets of composition capable of supporting life.
	medusa.as.arizona.edu /lbto/whybuild/sciex.html (1104 words)

	~@Com~\|~~BIG BANG THEORY UNDER FIRE~~ (Site not responding. Last check: 2007-10-23)
		It has been suggested that this singularity problem can be solved by postulating a universe of zero net energy;(2) a universe wherein the positive kinetic energy, the potential energy, and the Einsteinian equivalent energy of the mass of the universe is equal and opposite to the negative energy of gravity.
		One of the older problems of BBT, that of its postulated large-scale smoothness of the universe, appears to be the result of what was originally a simplifying assumption(5-8) that was made to aid in the solution of Einstein's equations of general relativity on which the BB is based.
		As in the case of the previously mentioned problems, the enormous rate of expansion of the early BB universe as postulated by inflation theory, is said to provide a solution to the flatness problem.
	nowscape.com /big-ban2.htm (7813 words)

	Cosmology
		Some of the greatest current problems in astrophysics arise from consideration of how the galaxies formed, and what is the nature of the mass of the universe (we can only identify 10 percent of what must be there!).
		A mass less than this value, will mean that the universe will go on expanding for ever, while a greater value will mean that the universe will expand to a maximum size, and then will start to contract -- eventually returning to a very small volume.
		Astronomers think that the mass of the universe is equal to this critical value, but we can only 'see' one tenth of the matter necessary to reach this value.
	www.oarval.org /cosmology.htm (1013 words)

	Assignment 10: Dark Matter (Site not responding. Last check: 2007-10-23)
		We measure the mass of the universe by estimates of the missing mass in galaxies and clusters of galaxies.
		Because of Fritz Zwicky's investigation of the missing mass problem, 90% of the universe remains to be found.
		The "missing matter problem" is important because it has people questioning the validity of current theories about how the universe was formed, and how it will ultimately end.
	www.aloha.net /~qopnop/assign10.htm (607 words)

	Chandra Education - Coma Activities & Image
		Your graph shows you that the intensity of the cluster steadily decreases from the center.(How is this different from the Cas-A result?) This is indicative of a mass of X-ray gas filling a region with the brightest area at the gravitational center of the cluster.
		This "missing matter" is inferred by observations of individual galaxies as well.
		For if we just assume that this missing matter exists, we are forced to predict other consequences in the appearances and motions of stars and galaxies that don’t really seem to fit the observed data.
	chandra-ed.harvard.edu /galaxies/coma_activity6.html (519 words)

	The fate of the Universe
		But there is a further missing mass problem, one that works on a scale even larger than that of our Galaxy, that is, out in the realm of galaxy clusters (some containing over 1,000 galaxies) and clusters of clusters ('superclusters').
		There is not enough ordinary matter to explain the total mass known to exist in galaxy clusters, and nowhere near enough to provide the mass-energy density needed to balance the Universe between eternal expansion and eventual re-collapse.
		The lower limit is itself too low to account for any significant fraction of the missing mass of the Universe, but the mass of the neutrino may well turn out to be greater.
	www.iac.es /galeria/agraham/Preprints/flatness/flatness-full.html (2527 words)

	SCIENTISTS SPEAK ABOUT STELLAR EVOLUTION - 2 (Site not responding. Last check: 2007-10-23)
		In as much as the gravitational force increases as the distance decreases, the force that is adequate to hold the cluster together should be more than adequate to drew the constituent stars together into a single mass, and why this does not happen has never been ascertained.
		A full 97 percent of the mass needed to hold galaxies together is missing.
		It seemed to be missing—hence the tag `missing mass."—Marcia Bartusiak, "Missing: 97% of the Universe," Science Digest, 91:51, December 1983.
	www.pathlights.com /ce_encyclopedia/02-star6.htm (1375 words)

	Samuel LIndsay-Levine
		The missing mass problem is extremely disquieting...We are talking about 90 percent of the mass of the universe, present but not speaking.
		The mass of the neutrons should be of the same order of magnitude as the electron mass and in any event not larger than 0.01 proton masses.
		Ultimately, although the neutrino was shown to have mass, and this went some way towards increasing the total mass we see in the universe, it was not sufficient to fully explain the missing mass problem.
	www.its.caltech.edu /~sciwrite/journal03/A-L/Linday-Levine.html (2760 words)

	Space Time Mass Home Page
		- The Missing Mass is one of the most important problems in modern astronomy - it is one of the biggest disagreements between our theories and what we can actually see in the sky, and has implications for the eventual fate of the Universe.
		Missing Mass is Around as Energy from the Big Bang - There has been a lot of debate over the nature of missing matter in the universe and people have been putting forward many candidates for this missing matter.
		MOA Project -- Missing Mass - Missing Mass M I C R O L E N S I N G O B S E R V A T I O N S I N A S T R O P H Y S I C S There are six major objectives for the MOA team.
	www.space-time-mass.com /faq.html (1092 words)

	Sacramento Peak: The Universe
		The expansion of the Universe is slowed down by the gravity of all the mass that is in the Universe.
		The mass density of visible matter (i.e., galaxies) in the Universe is estimated at 3e-28 kg/m^3 (3e-31 times the mass density of water).
		If the missing mass were mostly in the form of hydrogen atoms (which is not at all clear) then the number of atoms would be about 4e79.
	www.cs.umass.edu /~immerman/stanford/universe.html (2344 words)

	M (Site not responding. Last check: 2007-10-23)
		:A unit equal to one solar mass, that is, the mass of the Sun.
		mini fl hole: A fl hole the size of a pinhead (and thus the mass of an asteroid) or less, thought to be left over from the big bang; Stephen Hawking deduced that such mini fl holes should seem to emit radiation at a rate that allows a temperature to be assigned to it.
		missing-mass problem: The discrepancy between the mass visible and the mass derived from calculating the gravity acting on members of clusters of galaxies.
	astronomy.sierra.cc.ca.us /Resources/Reference/M.htm (914 words)

	Cosmology's Missing Mass Problems
		By assuming visual equilibrium,* he calculated the mass-to-light ratio and determined that about 90% of the mass necessary to account for the observed ratio was missing and therefore invisible.
		In 1940 Oort estimated (based on the Mass-to-light ratio of spiral nebulae) that 90% of the mass in the local group of spiral nebulae is "missing." Oort didn't cite Zwicky's 1933 paper (BSVD).
		The implication was that mass continues to increase with radius.
	www.datasync.com /~rsf1/missmass.htm (786 words)

	Cosmology's Missing Mass Problems - Part 2
		Hubble's increasing redshifts for galaxies at greater and greater distances came to be interpreted as being evidence of the required expansion of the universe, and thus the Big Bang came to be the paradigm.
		The author contends that cosmological redshift, as a velocity/distance indicator, has led to a universe whose size is grossly overestimated, and that the inflated "scale of the universe" has contributed to the first of the missing mass problems.
		missing mass problem (the flat rotation velocity curves of galaxies/spiral nebulae) is hypothesized to be related to our failure to take into account the electrodynamic interactions of moving interstellar plasma as it affects the group transport of visible galactic matter (stars and gases).
	www.datasync.com /~rsf1/missmas2.htm (1265 words)

	Dark Matter (Site not responding. Last check: 2007-10-23)
		The nature of this dark matter, and the associated "missing mass problem", is one of the fundamental cosmological issues of modern astrophysics.
		On smaller scales such as galaxies and clusters of galaxies, dynamical estimates of the mass based on rotation curves or velocity dispersions of galaxies indicate that 90% (not 99%) of the total mass is not seen ("sub-luminous").
		This implies that the mass density of the Universe is 10% of the closure density.
	csep10.phys.utk.edu /astr162/lect/cosmology/darkmatter.html (890 words)

	[No title] (Site not responding. Last check: 2007-10-23)
		In general, it is thought that it is almost impossible for a significant portion of the dark matter to be baryonic.
		Do note, however, that even of the few percent of baryonic mass, much of it is missing too.
		So, there are in fact two missing mass problems -- the missing baryonic mass and the real missing mass problem, which must be solved by a non-baryonic particle.
	cosmology.berkeley.edu /Education/FAQ/question8.txt (298 words)

	Bureau Of Missing Masses
		One of the most intriguing mysteries of astrophysics is the so-called "missing mass" problem: the mass of heavenly bodies as estimated on the basis of how much light they emit is vastly smaller than their mass as calculated through Newton's laws of gravity and motion.
		For example, according to Newton's law of inertia, the force (F) required to produce any level of acceleration (a) of a body of mass (m) is equal to m times a, or F = ma.
		If the mass of such bodies is determined in accordance with Milgrom's theory, referred to as MOdified Nonrelativistic Dynamics, then it is possible to account for all the matter estimated on the basis of the light they emit.
	www.eurekalert.org /pub_releases/1997-06/WI-BOMM-020697.php (433 words)

	In the Beginning: Compelling Evidence for Creation and the Flood - 57. Missing Mass
		This missing mass is called “dark matter,”; because it cannot be seen and, so far, has not been detected.
		Candidates for “missing mass” include neutrinos, fl holes, dead stars, low-mass stars, and various subatomic particles and objects dreamed up by cosmologists simply to solve this problem.
		The estimated mass of the visible universe is less than a 10th of this critical value.
	www.creationscience.com /onlinebook/ReferencesandNotes56.html (792 words)

	The search for the missing universe - smh.com.au
		Deep in a Yorkshire mine, scientists are toiling to solve a cosmic puzzle that has baffled astronomers for 70 years: about 90 per cent of the universe is missing.
		But measurements suggest that the universe is not what it appears: in 1933, the Swiss astronomer Fritz Zwicky observed that clusters of galaxies do not contain enough visible stars to explain how they rotate, as if the tug of something invisible twirls the stars around their fringes.
		Now the universe's missing mass might be about to be revealed as British astronomers fine-tune sensitive detectors 1100 metres beneath the north Yorkshire moors.
	www.smh.com.au /articles/2003/05/04/1051987611300.html (697 words)

	-- Beliefnet.com
		This “missing mass” problem may hold clues to the Big Bang and to the plane of the spirit.
		The latest physics may suggest where the missing parts of the universe are and in turn provide some hints about much larger questions--including whether there is an ethereal reality all around us.
		For instance, when cosmologists “weigh” the universe by estimating the mass of the components that shine, and thus are easy to detect (mainly, stars and nebulae), it appears the galaxies don’t contain anywhere near the amount of matter necessary to keep them from flying apart.
	www.beliefnet.com /story/17/story_1763_1.html (512 words)

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