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Topic: Baryonic dark matter

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	Baryonic dark matter - Wikipedia, the free encyclopedia (Site not responding. Last check: 2007-10-31)
		Baryonic dark matter is the dark matter (matter that doesn't emit light) composed of baryons, i.e.
		The total amount of baryonic dark matter can be calculated from big bang nucleosynthesis, and observations of the cosmic microwave background.
		If one assumes that all of the dark matter in the universe consists of baryons, then there is far too much deuterium in the universe.
	www.sciencedaily.com /encyclopedia/baryonic_dark_matter (196 words)

	Baryonic dark matter (Site not responding. Last check: 2007-10-31)
		matter thatdoesn't emit light) composed of baryons, i.e.
		Both tell that the amount of baryonic dark matter is muchsmaller that the total amount of dark matter.
		If oneassumes that all of the dark matter in the universe consists of baryons, then there is far too much deuterium in the universe.
	www.therfcc.org /baryonic-dark-matter-40906.html (168 words)

	Baryonic dark matter (Site not responding. Last check: 2007-10-31)
		matter that doesn't emit light) of baryons i.e.
		Both tell that the amount of dark matter is much smaller that the amount of dark matter.
		If one assumes all of the dark matter in the consists of baryons then there is far much deuterium in the universe.
	www.freeglossary.com /Baryonic_dark_matter (373 words)

	Cold Dark Matter and Intelligent Design
		The intelligent design suggests that cold dark matter could be made up of closed-string particles, which constitute the higher dimensional spirit world.
		The baryonic dark matter is made up of protons and neutrons such as non-luminous gas and stars.
		The majority of dark matter, however, is the cold dark matter which might be the spirit matter.
	www.web-books.com /GoodPost/Articles/DarkMatter.htm (684 words)

	HubbleSite - Astrofiles about "Hubble Rules Out a Leading Explanation for Dark Matter"
		Baryonic dark matter candidates include extra-solar planets, remnants of stellar evolution such as comets, objects not massive enough to ignite hydrogen fusion called brown dwarfs, dying embers of stars such as cold white dwarfs and neutron stars, as well as interstellar and intergalactic gases.
		Since all visible matter is only a small fraction of the total mass in the universe, the amount of dark mass that is present will determine the evolutionary future of the universe.
		Matter would gather in sizes comparable to current galaxies or smaller, and eventually build to become clusters and superclusters due to the gravitational attraction of the galaxies.
	www.hubblesite.org /newscenter/archive/1994/41/astrofile (1145 words)

	ARVAL-STScI - Dark Matter
		Dark matter [blue colored] and normal matter [red colored] have been wrenched apart by the tremendous collision of two large clusters of galaxies.
		This normal matter is bound in the cluster by the gravity of an even greater mass of dark matter.
		In contrast, the dark matter was not slowed by the impact, because it does not interact directly with itself or the gas except through gravity.
	www.oarval.org /darkmatt.htm (1334 words)

	laura baudis (Site not responding. Last check: 2007-10-31)
		the nature of dark matter in our galaxy is one of the great unresolved problems in science and several lines of evidence suggest that most of it might be non-baryonic.
		attractive candidates for non-baryonic dark matter are slow thermal relics born in an early phase of the universe.
		in the past, i was involved in direct dark matter detection and neutrinoless double decay experiments with high-purity ge diodes, such as the heidelberg-moscow experiment, the heidelberg dark matter search experiment (hdms) and the genius project.
	www.phys.ufl.edu /%7Elbaudis (325 words)

	Dark matter
		The dark matter that accounts for the critical density should, at least in the case of some kinds of dark matter, participate in the density fluctuations on large scales.
		The nature of the dark matter predicted by inflation is a profound and unresolved puzzle.
		Baryonic dark matter does exist: it is far more uncertain whether there exists enough to solve any of the dark matter problems, that is to say, dark matter in galaxy halos, dark matter in galaxy clusters and superclusters, or dark matter in an amount suficient to close the universe.
	astron.berkeley.edu /~mwhite/darkmatter/essay.html (3290 words)

	Star survey reveals part of the "missing mass" of the galaxy consists of ancient, dying stars
		There is the matter that glows, like stars and clouds of heated gas, that they can see and there is matter that is invisible, that cannot be seen but must exist because it exerts a detectable gravitational influence on the visible matter.
		Others maintain that not enough ordinary matter was made when the universe was created to account for all the dark matter that must exist so it must be made of something far more exotic.
		Dark matter has puzzled astronomers since Fritz Zwicky’s observation in 1933 that clusters of galaxies don't contain enough visible stars to explain their rotation.
	www.eurekalert.org /pub_releases/2001-03/VU-Ssrp-2203101.php (1206 words)

	exotic matter
		not made of baryons – the subatomic particles, such as protons and neutrons, of which ordinary matter is composed.
		Almost certainly most of the dark matter in the universe is non-baryonic and therefore made up of one or more forms of exotic matter.
		But we also know that, whatever dark matter is, it’s the primary source of gravitation in the universe; so it must have played a crucial role in determining the structure of everything from galaxies to the large scale arrangement of superclusters (clusters of clusters) of galaxies.
	www.daviddarling.info /encyclopedia/E/exotic_matter.html (1375 words)

	[No title]
		By measuring the gravitational pull of some unknown "dark matter" on the visible stars and galaxies, astronomers have determined that this mysterious material which seems to permeate the universe has a weight that is 60 times that of the stars and 7 times that of all baryons, including gas and solid material in space.
		There is so much of this dark energy, sometimes called quintessence or the cosmological constant, that it in effect has a weight almost twice that of all matter, dark or visible.
		In addition, she said, such a large quantity of baryons in galaxies like the Milky Way could not be reconciled with accepted theories of how elements formed in the Big Bang explosion in which the universe is thought to have been born.
	cdms.berkeley.edu /press/NYT_02_29_00.html (1001 words)

	What is Dark Matter?
		If the early baryon density was low, then it was hard for a proton to find a neutron with which to make helium before too many of the neutrons decayed away to account for the amount of helium we see today.
		And there must be some non-baryonic dark matter to account for the remaining 95% of the matter required to give omega, the mass of the Universe, in units of critical mass, equal to unity.
		Dark Matter (Proceedings of the XXIIIrd Recontre de Moriond), J. Audouze and J. Tran Thanh Van.
	math.ucr.edu /home/baez/physics/Relativity/GR/dark_matter.html (810 words)

	non-baryonic matter
		Matter that, unlike all the kind kinds of matter with which we are familiar, is not made of baryons (including the neutrons and protons found in all atomic nuclei).
		Therefore, the imprints left by the non-baryonic matter in the cosmic background radiation would be different than those left by the baryonic matter.
		This attribute could be used to measure the contribution of non-baryonic matter to the total amount of mass in the universe.
	www.daviddarling.info /encyclopedia/N/non-baryonic_matter.html (213 words)

	More than Meets Eye
		Inflationary theory predicts that the universe is flat--that the average density of matter in the universe exactly equals the critical density required to close the universe.
		Some dark matter may simply be ordinary, or "baryonic" matter made of protons, neutrons and electrons that fails to emit radiation detectable on Earth.
		Hot dark matter, on the other hand, is made up of light-weight particles that move near the speed of light.
	archive.ncsa.uiuc.edu /Cyberia/Cosmos/MoreMeetsEye.html (750 words)

	CERN Courier - Missing baryons found in hot - IOP Publishing - article (Site not responding. Last check: 2007-10-31)
		While it is well known that ordinary baryonic matter constitutes only about 5% of the total energy content of the universe, it is probably less commonly appreciated that about half of this "known" matter has never been identified, even in our galaxy's neighbourhood.
		Baryons - the three-quark particles such as protons and neutrons - are used to define ordinary matter, because the other known particles are either like pions, too short-lived, or like electrons, too light to contribute significantly to the mass of the universe.
		According to cosmologists, however, all this amounts to only about half of the existing baryonic matter in the universe, which is itself only about 5% of the matter-energy content of the universe.
	www.cerncourier.com /main/article/45/2/14 (624 words)

	Queen's Physics Department
		Dark matter is also necessary to hold groups and rich clusters of galaxies together.
		An appealing possibility is that dark matter is made of ordinary baryonic material (i.e., protons, neutrons, etc.) that simply doesn't radiate.
		Our work suggests that future dark matter detection experiments should be able to see features in energy and angular spectra that are associated with the structure of the Milky Way's dark halo.
	www.astro.queensu.ca /~widrow (807 words)

	SPACE.com -- Understanding Dark Matter and Light Energy
		This mysterious "dark matter" is believed by most scientists to be the most common stuff in the universe, perhaps making up 90 percent or more of the total mass.
		Dark matter -- or something that we have yet to find -- exerts a gravitational pull on objects in and around distant galaxies, and even on light emitted by those objects, say scientists at NASA's Goddard Space Flight Center.
		Normal matter -- you, your computer and the air you breathe -- is made of atoms, which are composed of protons, neutrons and electrons.
	www.space.com /scienceastronomy/astronomy/dark_matter_sidebar_010105.html (674 words)

	The website of Halton Arp - Forum (Site not responding. Last check: 2007-10-31)
		The Big Bang posits that most of the matter in the universe is non-baryonic (exotic particles) and that only a small fraction of matter is baryonic (normal protons, neutrons, and electrons).
		So if the dark matter is baryonic, you have a major problem for the Big Bang, because the nucleosynthesis pillar is blown apart, but you can still have your general relativity, which to this point seems to have survived the tests put to it.
		Dark Energy is one of the most remarkable bandwagons in the history of science.
	www.haltonarp.com /?c=view_topic.include.cfm&view_topic_id=11&page_index=49 (1532 words)

	Glossary of Astronomical and Cosmological Terms
		dark matter: a form of matter that does not emit light, absorb light, or scatter light.
		hot dark matter: a type of dark matter that was moving at close to the speed of light 10,000 years after the Big Bang.
		The neutralino is the lightest electrically neutral supersymmetric partner, and it is a candidate for cold dark matter.
	www.astro.ucla.edu /~wright/glossary.html (1935 words)

	Baryonic matter (Site not responding. Last check: 2007-10-31)
		From Latin materia (matter, stuff, material), derivative of Latin mater (mother).
		Matter always consists of a mass and a volume.
		This journal covers the whole of condensed matter physics including soft condensed matter and nanostructures, plus experimental, theoretical and simulation studies.
	www.serebella.com /encyclopedia/article-Baryonic_matter.html (525 words)

	WMAP Cosmology 101: Matter in the Universe
		New forms of matter: particle physicists, scientists who work to understand the fundamental forces of nature and the composition of matter, have speculated that there are new forces and new types of particles.
		It is also able to determine some of the properties of the non-baryonic matter: the interactions of the non-baryonic matter with itself, its mass and its interactions with ordinary matter all affect the details of the cosmic microwave background fluctuation spectrum.
		WMAP determined that the universe is flat, from which it follows that the mean energy density in the universe is equal to the critical density (within a 2% margin of error).
	map.gsfc.nasa.gov /m_uni/uni_101matter.html (1033 words)

	Spaceflight Now \| Breaking News \| White dwarfs shed light on dark matter
		Some of the invisible "dark matter" that makes up most of the mass of our galaxy may be in the form of previously undetected white dwarf stars, astronomers reported this week.
		The mystery of dark matter dates back to the 1930s, when astronomer Fritz Zwicky measured rotation rates of galaxies that were much higher than expected given their estimated masses.
		While the focus of the paper is on the potential for white dwarfs to explain the dark matter in the galaxy, the research also plays a role in understanding stellar evolution.
	www.spaceflightnow.com /news/n0103/23darkmatter (1073 words)

	Frequently Asked Questions
		Some dark matter, such as dim stars, is extremely faint but does emit a minute amount of light.
		The disk rotates and at the distance of the Sun from the center of the Galaxy (roughly halfway along a radius of the disk) it is spinning at approximately 220 kilometers per second.
		Although it is possible that white dwarfs may comprise a substantial fraction of the baryonic dark matter, non-baryonic dark matter must still exist and by most estimations it dominates the mass of the universe.
	www.ast.cam.ac.uk /~sth/halowd/faq.html (1714 words)

	Dark Matter
		Dark matter as a puzzle inspires astrophysicists and particle physicists, amalgamating these research areas into the rather young discipline of astroparticle physics.
		The exercise is clear: to reveal the nature of dark matter and its role in the universe.
		To conclude, dark matter appears to be well established as a phenomenon in astrophysics, a fascinating puzzle.
	www.europhysicsnews.com /full/12/article15/article15.html (1969 words)

	SPACE.com -- 'Groundbreaking' Discovery: First Direct Observation of Dark Matter
		More than three dozen elusive whitedwarf stars have been found in a halo of objects surrounding our galaxy,marking the first direct evidence for previously unseen "darkmatter" and lending support to a widely held theory that there is muchmore to the universe than meets the eye.
		Thehunt is still on for a more exotic type of dark matter, called nonbaryonic,assumed to be made of strange particles that behave in ways not entirelyknown.
		Looking at it this way, dark matter is all aroundus, said Oppenheimer, the lead author of the study, in a telephone interview."You as a human being are in a sense dark matter, although in the infraredyou would look like a hundred-watt light bulb."
	www.space.com /scienceastronomy/astronomy/missing_matter_found_010322-1.html (898 words)

	Dark Matter Search (SEDS HST Archive 16 of 135)
		(Dark matter is material of an unknown type that makes up most of the mass of our galaxy).
		If the dark matter in our Galaxy was made of faint red stars -- as many scientists have previously conjectured -- then about 38 such stars should have been visible in this HST image.
		This region was chosen to highlight stars in the galactic halo, where dark matter exists, and to avoid the contribution of faint stars in the plane of the Galaxy.
	www.seds.org /hst/DarkMatA.html (280 words)

	Re: Explaining dark matter with black holes
		I feel compelled to point out for the readers who aren't up on dark matter that there are several kinds of "dark matter problem".
		are all candidates for baryonic dark matter Third: detailed analysis of spiral galaxy rotation curves (done in the 1960's and on) surprised people by being flat.
		So anyway, when people talk about dark matter, they are referring to many kinds of evidence for several different critters - sometimes people mean non-baryonic dark matter (axions or cosmic strings or whatever) and sometimes they mean anything not glowing; sometimes they mean something in between.
	www.lns.cornell.edu /spr/2003-05/msg0050912.html (489 words)

	Baryonic DM?
		The question it raises is, "What form does this baryonic matter take and why has it not been observed?" If DM were gas and dust it would absorb light, if bright stars they would be seen, if fl holes or dim stars they would be observed through micro-lensing events.
		they cite the possibility that baryonic dark matter can be in the form of "primordial fog particles", that should exist forming clumps, though it seems that this kind of dark matter is explained in a Top-Down scenario, while the vast majority of scientists prefer the Bottom-up scenario of structure formation.
		The baryonic mass content of galaxy clusters is dom-inated by the X-ray emitting intracluster gas, the mass of which exceeds the mass of optically luminous material by a factor ~ 6
	www.physicsforums.com /showthread.php?t=61596 (1703 words)

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