by soft+gentle 44 Replies latest watchtower beliefs
I heard that there was a equal amount of matter and dark matter, in the begining.. when they colide massive explosion.. there is a slight advantage to matter. all the dark matter is gone.. the universe is what is left.. this was an experiment with the particle colider, I saw on some science channel..
any way my 2cents..
late tate
Lol!
I am with WMF, i think he is mixing things together. An atom is mostly composed of empty space, but it is a lot more than 90% so i dont think that is the factoid he is getting wrong.
At its basis there is something funky about the claim: 'Space' indicate volume, and mass is an odd measure of volume. I think he refer to one of two things:
my money is on the later since it is (after all) easier to confuse rest mass of a quark with space inside an atom (hey... they are both small!) than confusing an atom with the entire universe.
I got no clue why this has anything to do with god.
Tater: You are thinking about antimatter, ie. matter made out of the anti-particles of ordinary matter. Dark matter is very real*, and there is a lot more dark matter than ordinary matter.
* assuming dark matter exist, ofcourse, so far we only have indirect (but very encouraging!) observations of it, it has so far not made anything go click in an accelerator ;-).
@ bohm... yes you are right, was thinking that as i wrote... it was anti matter.. they were talking about, my bad..
* assuming dark matter exist, ofcourse, so far we only have indirect (but very encouraging!) observations of it, it has so far not made anything go click in an accelerator ;-).
Many scientists are skeptical of the dark matter/dark energy suppositions. Not only is there zero experimental evidence, but there is not even a hint of such constructs in any present particle theory.
Until further proof is available - the effects attributed to dark matter/dark energy could very well be coming from something else.
And no, it is ridiculous to suggest that atoms are 99% dark matter.
I'm not going to pretend to be the authority on dark matter here, but neither should most of the people posting in this thread who are clearly assuming quite a bit.
It sounds like he was partially right. Most people know that the majority of an atom is empty space; however, that doesn't mean that empty space doesn't weigh anything. This is where dark matter and dark energy come into play, because all of weight of atoms in a human body that can be measured don't account for a large majority of our mass. Recently, scientists have started to change the way they think about empty space...perhaps it's not really empty after all; rather, it's a frothing, highly excited field of dark energy that is waiting to pop into existence.
It was a year or so back that I first read of this, but you can see on Nasa's website with a google search that most of the mass in the universe (70%-90%) is unaccounted for by the mass of atoms alone. It seems we are somewhat floating in a dark matter / energy soup that accounts for most of the mass in the universe.
James, when they add up the mass of all atoms in the universe, it's not even close to what the universe weighs...this is why something massive that we can see or directly measure has to exist, to account for the missing mass we measure. This is hardly controversial. Dark matter and dark energy is simply a placeholder, a gap filler, for the mass and energy that is obviously acting on galaxies and other massive objects for which no other explanation exists.
http://www.scientificamerican.com/article.cfm?id=what-are-dark-matter-and
Ultimately, very strong arguments have been made that at most 5 percent of the mass-energy density of the universe, and 20 percent of the mass of clusters, is in the form of atoms.
http://imagine.gsfc.nasa.gov/docs/science/know_l2/dark_matter.html
"Dark matter" refers to matter of an unknown nature that many astronomers and cosmologists think must make up the majority of the mass in the universe. Its presence is revealed by the gravitational effects on objects that we can see. According to the current understanding of how gravity works, the way the visible matter behaves indicates that there should be much more matter than we can detect — and therefore, much more mass exerting a gravitational influence — in objects in space, like stars in galaxies, or galaxies in clusters. The clusters move at speeds that are too high to be attributed just to the visible galaxies.
http://map.gsfc.nasa.gov/universe/uni_matter.html
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 1% margin of error). This is equivalent to a mass density of 9.9 x 10 -30 g/cm 3 , which is equivalent to only 5.9 protons per cubic meter. Of this total density, we now know the breakdown to be:
4.6% Atoms. More than 95% of the energy density in the universe is in a form that has never been directly detected in the laboratory! The actual density of atoms is equivalent to roughly 1 proton per 4 cubic meters.
23% Cold Dark Matter. Dark matter is likely to be composed of one or more species of sub-atomic particles that interact very weakly with ordinary matter. Particle physicists have many plausible candidates for the dark matter, and new particle accelerator experiments are likely to bring new insight in the coming years.
72% Dark Energy. The first observational hints of dark energy in the universe date back to the 1980's when astronomers were trying to understand how clusters of galaxies were formed. Their attempts to explain the observed distribution of galaxies were improved if dark energy was present, but the evidence was highly uncertain. In the 1990's, observations of supernova were used to trace the expansion history of the universe (over relatively recent times) and the big surprise was that the expansion appeared to be speeding up, rather than slowing down! There was some concern that the supernova data were being misinterpreted, but the result has held up to this day. In 2003, the first WMAP results came out indicating that the universe was flat (see above) and that the dark matter made up only ~23% of the density required to produce a flat universe. If 72% of the energy density in the universe is in the form of dark energy, which has a gravitationally repulsive effect, it is just the right amount to explain both the flatness of the universe and the observed accelerated expansion. Thus dark energy explains many cosmological observations at once.
I'm not going to pretend to be the authority on dark matter here, but neither should most of the people posting in this thread who are clearly assuming quite a bit.
It sounds like he was partially right. Most people know that the majority of an atom is empty space; however, that doesn't mean that empty space doesn't weigh anything. This is where dark matter and dark energy come into play, because all of weight of atoms in a human body that can be measured don't account for a large majority of our mass. Recently, scientists have started to change the way they think about empty space...perhaps it's not really empty after all; rather, it's a frothing, highly excited field of dark energy that is waiting to pop into existence.
Well dorkydood, you are mostly wrong :-).
"because all of weight of atoms in a human body that can be measured don't account for a large majority of our mass."
Like i (and other) have allready written, relativistic/QFT corrections to the *rest mass* of quarks in the elementary particles account for the great majority of their mass. but this has nothing to do with space inside an atom, it has to do with the energy in gluon fields which are there because, well, there are quarks. I will give you that the weight of the atoms in your body do not add up to your mass, but if you divide by the gravitational acceleration they do ;-).
on the large scale there is dark energy which can be observed (indirectly) on the cosmic scale, but that is something else entirely.
Perhaps to illustrate why the statement by the speaker must be wrong: Suppose that "empty space" really did account for 90% of the mass of an atom. This mean ALL empty space roughly have the same density of an atom, in other words, the universe would collapse to a black hole in no time (or rather, it would allready be a giant black hole). Since we are not all dead, that is not the case.
James_Woods: The emperical status of dark matter is not as bleak as it is often laid out in popular science, see for instance: http://en.wikipedia.org/wiki/Dark_matter#Observational_evidence. True none of these are /direct/ measurements (but neither did we have direct measurements of the neutrino for quite some time), and some can be explained alternatively, but together they paint a pretty suggestive picture and i think it is fair to say that at this time the simplest explanation is dark matter.
James, when they add up the mass of all atoms in the universe, it's not even close to what the universe weighs
Two questions:
1) how on earth can they "add up the mass of all atoms in the universe"? - note that they cannot even see them all...
2) how on earth do they know what the universe weighs?
One thing is clear - dark matter / dark energy could either be the greatest scientific discovery in a generation (if proven) - OR -
It could be the 21st century version of the disproven "ether" which was supposed to transport light waves, disproven at the start of the 20th century.
With all due respect bohm, I'll go with the information on Nasa's website, which seems to support what I'm saying...unless I am misunderstanding what is stated on their website?
Most of an atom is empty space. That empty space "weighs" something. According to the several sources I've mentioned, dark matter and dark energy can account for that mass.
