Has anyone found evidence of dark matter within galaxies? Or is this strictly a "Halo" thing?
Star
Star
- Status
The existence of DM inside a galaxy was what initially started us thinking about it. The presence of DM in the halo regions has been studied later, in an effort to map and understand it's overall distribution.
The orbital velocities of stars within galaxies cannot be explained by the amount of visible mass (stars dust etc), so the postulate for dark matter. Also the motion of galaxies in clusters needs extra unseen mass to hold them together. Gravitational lensing of galaxy clusters shows that this dark matter extends well beyond visible galaxies ie in their halo's. Matching what we know from star motions in galaxy.
The stars of a galactic halo spread throughout a roughly spherical volume that includes and extends beyond the spiral arms and core.
These was an idea that the dark matter could be in the form of objects like black holes, brown dwarfs, old white dwarfs etc ie Massive Compact Halo Objects. (MACHO). But a search using gravitational microlensing looking toward the Magellanic clouds showed very little sign of such objects. Similar studies looking toward the galactic center show no great population of black holes etc. So best guess is that dark matter is made up of Weakly Interacting Massive Particles (WIMPS).
A modified version of gravity MOND also can explain the motions of stars, galaxies ... It might have trouble explaining the gas heating seen in the collision of 2 galaxy clusters.
The stars of a galactic halo spread throughout a roughly spherical volume that includes and extends beyond the spiral arms and core.
These was an idea that the dark matter could be in the form of objects like black holes, brown dwarfs, old white dwarfs etc ie Massive Compact Halo Objects. (MACHO). But a search using gravitational microlensing looking toward the Magellanic clouds showed very little sign of such objects. Similar studies looking toward the galactic center show no great population of black holes etc. So best guess is that dark matter is made up of Weakly Interacting Massive Particles (WIMPS).
A modified version of gravity MOND also can explain the motions of stars, galaxies ... It might have trouble explaining the gas heating seen in the collision of 2 galaxy clusters.
bdewoody":pvfotpv6 said:
If you mean antimatter, no.
I think the consensus is that antimatter has negative nuclei and positive elctrons.
However, imo dark energy behaves like some kind of matter-opposite. Dark energy seems to
have no mass, unlike matter. It also seems to expand spacetime, unlike matter; it even seems
to behave like anti-gravity, unlike matter which is related to gravity.
bdewoody":1swgce2z said:
Assuming you do indeed mean anti-matter, no.
From a distance, anti-matter would look and act exactly like regular matter, producing and absorbing electromagnetoic radiation (which is how we detect matter in space) in the same way.
I was just wondering because Galaxies seem to act like solids. Combine that much dark matter mass and regular matter mass all in the same place and perhaps it acts like a solid.
If I take a circle of paper and punch a pencil through it, then spin it, the middle spins at the same rate as the outside edge, and this is because the circle of paper is solid, it is one thing (two if you count the pencil)
A galaxy behaves the same way, as though it were a solid, one thing instead of billions of little things, or better yet, billions of little things acting as one thing. But one solid thing. At least in this aspect it does.
Star
If I take a circle of paper and punch a pencil through it, then spin it, the middle spins at the same rate as the outside edge, and this is because the circle of paper is solid, it is one thing (two if you count the pencil)
A galaxy behaves the same way, as though it were a solid, one thing instead of billions of little things, or better yet, billions of little things acting as one thing. But one solid thing. At least in this aspect it does.
Star
A galaxy doesn't act like a solid at all!
First of all, it is made of billions of stars each in it's own orbit. And second, the outer stars do not roate at the same rate as the inside stars (like a solid). It's just that they don't rotate as slowly as they would if there were not some invisble mass.
First of all, it is made of billions of stars each in it's own orbit. And second, the outer stars do not roate at the same rate as the inside stars (like a solid). It's just that they don't rotate as slowly as they would if there were not some invisble mass.
Ahhh I see, I was under the impression that they moved at the same or near the same speed.
So how much faster are these stars moving in comparison to how fast they should be moving?
Star
So how much faster are these stars moving in comparison to how fast they should be moving?
Star
bdewoody":11erlf7k said:
in the dark :lol:
Did you mean dark matter or dark energy? And what is your thought process [if matter]?
[if energy:] When antimatter was conceived, I think we should have called it electronegative ordinary matter, so
when dark energy was conceived we could have called it antimatter?
Re: Risky asteroid 2009 WM1(Nov 2009)
In High School at a swimming party, I was given a problem to solve. They did not have a solution and did not
know what happened. It took 28 years to solve. In the solution, Al was transpormed to Hydrogen and back to Al.
Could it be that is you use Fe instead and calculate the Hydrogen in the Solar System including the Solar Wind,
etc. and multiply it by 1620 that you could account for the Missing Matter ???
While in LA, it took 45 minutes to comute to work on the Freeway. The ideal come to me that the Freeway was a
fluids lab. With you reaction time included. I decided to creat a bubble and see if would go faster in my commute.
It took with the bubble which is an interesting thing. It took only 15 minutes to travel up the Old highway into the
Valley. The thought came to me who needs three times more people in LA? The Highway Dept. decided to improve
the commute time on the same route. It took 4.5 hours to do what I was doing in 15 minutes. WOW !!!!!
In our fluids course, the instructor told an interesting story. A builder of war ships got tired of having the Japanese
stealing his plans and building advanced ships. So, he designed a ship that would tip over. Just before the prints
diagrams wer printed, he had the drafts make two changes which made the ship look good. The japanese built
and either the Emperior's Wife and the Head of the Japanese Navy were on the ship similar to the Movie Titanic or
the Wife only. The Ship went down the ramp and tilted over dumping the Wife or Wife and the Head of their Navy
in the Ocean. They lost Face, and Pearl Habor occured. WOW !!!!!!!!
Sincerely yours,
Don
Graduate Engineer and Scientist
P.S. With my ideas two Phd.s are brought in as my mentor said. One on my answer and one on the other side.
It was hard not to not interact with the Phd.s and influence the answer, but I did. The true answer developed
on it's own. I found out the Phd's think they are so smart, but the true smart Phd's are humble and I admired
the humble Phd's.
Have a great day !!!!!!!!
In High School at a swimming party, I was given a problem to solve. They did not have a solution and did not
know what happened. It took 28 years to solve. In the solution, Al was transpormed to Hydrogen and back to Al.
Could it be that is you use Fe instead and calculate the Hydrogen in the Solar System including the Solar Wind,
etc. and multiply it by 1620 that you could account for the Missing Matter ???
While in LA, it took 45 minutes to comute to work on the Freeway. The ideal come to me that the Freeway was a
fluids lab. With you reaction time included. I decided to creat a bubble and see if would go faster in my commute.
It took with the bubble which is an interesting thing. It took only 15 minutes to travel up the Old highway into the
Valley. The thought came to me who needs three times more people in LA? The Highway Dept. decided to improve
the commute time on the same route. It took 4.5 hours to do what I was doing in 15 minutes. WOW !!!!!
In our fluids course, the instructor told an interesting story. A builder of war ships got tired of having the Japanese
stealing his plans and building advanced ships. So, he designed a ship that would tip over. Just before the prints
diagrams wer printed, he had the drafts make two changes which made the ship look good. The japanese built
and either the Emperior's Wife and the Head of the Japanese Navy were on the ship similar to the Movie Titanic or
the Wife only. The Ship went down the ramp and tilted over dumping the Wife or Wife and the Head of their Navy
in the Ocean. They lost Face, and Pearl Habor occured. WOW !!!!!!!!
Sincerely yours,
Don
Graduate Engineer and Scientist
P.S. With my ideas two Phd.s are brought in as my mentor said. One on my answer and one on the other side.
It was hard not to not interact with the Phd.s and influence the answer, but I did. The true answer developed
on it's own. I found out the Phd's think they are so smart, but the true smart Phd's are humble and I admired
the humble Phd's.
Have a great day !!!!!!!!
I interviewed Michio Kaku earlier this year (for EnlightenNext magazine) and we got to speaking about dark matter. What struck me most was that he said an entire mountain of dark matter could pass through us right now and we wouldn't even notice it. Its interactions with normal matter are presumably nonexistent except for its gravitational effect, and the gravity of a mountain-sized mass is negligible next to that of the earth.
In a previous series of interviews I did in my continuing fascination with dark matter & dark energy (you can see the edited results here: http://www.enlightennext.org/magazine/j ... e-dark.asp), a biophysicist named Deno Kazanis speculated that what we're calling dark matter may actually be the "subtle matter/energy" that mystics have spoken of for millennia. If so, he suggested, it could provide a scientific basis for paranormal phenomena -- from auras to ghosts to UFOs and beyond. And the dark matter, in that scenario, would be coexistent with ordinary matter pretty much everywhere that normal matter occurs (so dark matter would be surrounding your body, for instance). It's a wild idea, but it's kept me wondering...
In any case, I'm intrigued by this general idea that dark matter is potentially everywhere -- and we only notice it on the galactic scale because we're currently only able to measure it (via gravitational effects) on such an enormous scale. But with time, our ability to detect and locate it will become more precise.
In a previous series of interviews I did in my continuing fascination with dark matter & dark energy (you can see the edited results here: http://www.enlightennext.org/magazine/j ... e-dark.asp), a biophysicist named Deno Kazanis speculated that what we're calling dark matter may actually be the "subtle matter/energy" that mystics have spoken of for millennia. If so, he suggested, it could provide a scientific basis for paranormal phenomena -- from auras to ghosts to UFOs and beyond. And the dark matter, in that scenario, would be coexistent with ordinary matter pretty much everywhere that normal matter occurs (so dark matter would be surrounding your body, for instance). It's a wild idea, but it's kept me wondering...
In any case, I'm intrigued by this general idea that dark matter is potentially everywhere -- and we only notice it on the galactic scale because we're currently only able to measure it (via gravitational effects) on such an enormous scale. But with time, our ability to detect and locate it will become more precise.
The sock has already been explained. Electrostatic discharge builds up in the dryer opening a wormhole to the missing sock dimension. The only way to prevent this is to collapse the worm hole with three dryer sheets.
duh
As far as dark matter being the Aether, I don't know. Mystics like to do stuff with shiny flashy things. They get you to watch one hand while the other empties your pockets. But even if you were right then that would imply that dark matter would have a measurable charge, (something for the mystics to "tap") and if that were the case I think it would interact differently with normal matter with an opposite charge.
Star
duh
As far as dark matter being the Aether, I don't know. Mystics like to do stuff with shiny flashy things. They get you to watch one hand while the other empties your pockets. But even if you were right then that would imply that dark matter would have a measurable charge, (something for the mystics to "tap") and if that were the case I think it would interact differently with normal matter with an opposite charge.
Star
Hi, first post here, I hope it's not dumb as ****. Is it not possible that a very large part of the "missing mass" is an enourmous black hole, that's not in the center of a galaxy, but in the "center" of the universe? I mean the galaxies must orbit around something, right?
I suppose it doesn't... But if you think about it, it's not impossible. I'm not sure about what's the biggest scale we know about is (groups of galaxy-groups perhaps) but ultimately mustn't they also orbit around something? And that something... mustn't it orbit around something else? Intuitionally it feels like it boils down to some object really being the center of all things. First we thought the earth was the center of the universe, then the sun, then we realized the sun is orbiting the Milky Way, and then we discovered more galaxies etc. I feel like there can be many more "steps" (perhaps there are, of which I'm not aware), only they're at such a large scale they're very hard to observe. Sorry if I strayed a bit OT.
First of all, there is no center of the Universe....
and secondly, every point in the Universe is its center
weird, isn't it
and secondly, every point in the Universe is its center
weird, isn't it
NoSplitvision":1rezbvbl said:
No
The Universe is not orbiting around any singular point...partly because there is no center to the Universe.
The whole Universe has expanded from every point equally. There is no center for anything to orbit around.
Yes intuitively it does. Unfortunately, and it is the hardest thing to understand, that intuition is wrong.
Far more than theories... depending on what you mean by that word theory.
If you suggesting it is wild unsupported speculation, it's far stronger than that.
It is a theory that is supported by all evidence collected to date. Could it be wrong? Sure. Is there any realistic evidence that supports the idea it is wrong? No.
If you suggesting it is wild unsupported speculation, it's far stronger than that.
It is a theory that is supported by all evidence collected to date. Could it be wrong? Sure. Is there any realistic evidence that supports the idea it is wrong? No.
Currently the expanding universe theory and the big bang are the closest theories that match observations.
Its important to remember that a theory for the universe must be all inclusive. If all Galaxies were orbiting a common "center" of the Universe, then would that not mean that they were accelerated twords the center of the Universe,(remember, any change in direction or velocity in space is considered "acceleration", even if you slowed down) and (correct me if I am wrong here) would that not be a property of a contracting Universe, and not an expanding one?
Star
Its important to remember that a theory for the universe must be all inclusive. If all Galaxies were orbiting a common "center" of the Universe, then would that not mean that they were accelerated twords the center of the Universe,(remember, any change in direction or velocity in space is considered "acceleration", even if you slowed down) and (correct me if I am wrong here) would that not be a property of a contracting Universe, and not an expanding one?
Star
No, I think according to the question about the universe in rotation,
and depending on the size of the universe, galaxies would be moving in certain definite directions.
...Something similar to the mysterious dark flow patch, except everywhere.
(If the universe was only as small as the observable universe, for example, then that would put
the Milky Way at or near the center. And only in this situation, all galaxies would revolve around
or near the Milky Way.)
and depending on the size of the universe, galaxies would be moving in certain definite directions.
...Something similar to the mysterious dark flow patch, except everywhere.
(If the universe was only as small as the observable universe, for example, then that would put
the Milky Way at or near the center. And only in this situation, all galaxies would revolve around
or near the Milky Way.)
Fascinating discussion. What about the acceleration (or even speed) of dark matter - would that impact it's effect on surrounding objects?
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