Dark matter?

[Farabi]

I believed to the dark matter thing before, but after I know how the human vision pathway work, I thing it is a misunderstand.
On my opinion, the universe dark because it was huge. All photon that travel to the edge looses its power to vibrating and stopped, that is why everything is dark. As we can see, our eyes had a spectrum on a thresholded range of the vibration. I dont know how can the sun lights hurt our eyes if we directly see it, but if it is painfull, it mean our eyes is damaged. X ray is something that we cant see, but how we can see the sun light but we cant see a light above x-ray? Sun light got to be more powerfull than the visible light power.

There is no dark matter. It was just our universe is huge. Huge enough to make the light loose its power when it travels.

[Bill Cravener]

No Farabi, I think you are wrong, there is such a thing as dark matter, and the older I get the more of it I acquire. :bg

[mineiro]

 :lol :lol :lol Sr Bil lCravener  :U
The dark make us blind, and much light make us blind too.

[Tedd]

A photon of light will continue to travel forever, without losing energy, unless it is stopped by something else.
The reason beams of light appear to get dimmer as they travel is due to dispersion (they spread out) so there are less photons to see in a given area.
Lasers spread considerably less, so they can go much farther before dimming, and that's what makes them appear 'strong.'

The universe is dark because it's so large, and there is so much 'empty' space, that there are stars soooooo far away their light hasn't yet reached Earth even though it's been traveling for billions of years.
The clues for dark matter are related to gravity, not light. It's named dark because we can't detect anything (including light) coming from it; but we can see the gravitational effects it has on other things that we can detect.

We can see sunlight because our eyes are tuned to detect those frequencies. We don't see x-rays because they serve little purpose to us (and they're quite damaging to cells.) The Sun also gives out x-rays, ultra-violet, infra-red, and numerous other frequencies - it has little to do with power (x-rays are actually more powerful than visible light) and more to do with frequency.

[dedndave]

Tedd's onto it   :P

what physicists describe as "dark matter" or "dark energy" are possibly the effects of the unseen black holes that exist in the universe
i tend to think of black holes as "junk yards" of the universe - lol
they collect shit and, generally, keep it from the public eye
can't get any more technical than that on my first cup of coffee   :bg

[FORTRANS]

Hi,

   Black holes are a small part of dark matter, if a part of it
at all.  Most, if not all, black holes are accreting matter and
spitting some back out in very bright jets.  And have nothing
to do with dark energy.

   Observation of the movement of stars within galaxies, the
retention of hot gas in galaxy clusters, movement of galaxies
in galaxy clusters, and gravitational lensing show that matter
that we see only accounts for ~27% of all matter that produces
gravity.  The movement of the universe implies a dark energy
that is modifying the overall size of the universe.  Adding
that in and visible matter is less than 10% of the "stuff" that
is "in" the universe.

   Candidates for dark matter include Weakly Interacting Massive
Particles (WIMPs), Massive Compact Halo Objects (MACHOs),
axions, neutrinos, and other stuff.  Some MACHOs could be
naked black holes.

   The dark nighttime sky is known as Olbers' Paradox.  Edgar
Allan Poe wrote an essay on that problem.  Basically the sky is
dark because there hasn't been enough time to have light
coming from all points in the sky.  The universe expanding
implies there never will be enough time.

Regards,

Steve N.

[FORTRANS]

Hi,

   Something to slow you down, mostly pretty pictures.

Cheers,

Steve N

Cluster Crash Illuminates Dark Matter Conundrum
Dark Matter Ring Modeled around Galaxy Cluster CL0024+17
Dark Matter Map
Dark Matter, X-rays, and NGC 720
Distant Supernova, Dark Energy
Dark Energy, Dark Matter.

[dedndave]

great info, Steve   :U

but, i think you forgot one...
Dark Vader

:bg

[baltoro]

I just love a good mystery,...
Especially, one that makes absolutely no sense at all,...

[dedndave]

i like this one
it serves to remind us that we don't know everything there is to know about the world we live in

[baltoro]

DAVE !!!
That seems to be your favorite theme,...
I myself don't believe that Dark Matter is a reality. I think we just don't understand gravity at the cosmogenic level,...

[dedndave]

truthfully, we don't understand gravity on any level - lol
my favorite physics "problem"
Newton helped a lot by deriving some formulas to describe it's behaviour
however, they do not explain the true nature of it's existance
very much a piece of the "unified theory" puzzle

[hutch--]

The funny part is that there is no evidence for dark matter or dark energy at all, both have been postulated to account for observable phenomenon in the universe. We know from spectral shift that the universe is expanding and at an an accelerating rate but even that assumes the reaches of the universe over billions of years behave in the same manner as close observable phenomenon.

As a rough description the "Big Bang" theory more of less fits the observable data but it hardly gives you a working chronology of any great reliability. The problem is there is no easily constructed method of verification of cosmological theory as the universe in the form we understand it is beyond a scale that we can travel around.

[baltoro]

HUTCH,
You stated it perfectly. If you examine Newtonian solutions for the orbital configuration of just our local Solar System,...and, if you then try to extend these statistics dynamically either forward or back in time,...the solutions diverges into chaos within a period of a few hundred thousand years.

[dedndave]

that's right
we don't know what's going on beyond the "walls" of our universe
i.e., the big bang was an event that occured something like 14.8 billion years ago
we cannot see beyond that - and even if we could, we don't have great technology for seeing things