Widdekind Posted October 20, 2012 Posted October 20, 2012 Billions of years ago, early spiral galaxies had more gas, fewer stars, yet much higher star formation rates. Over the eons, those galaxies have evidently "disked down & spun up", whilst converting their primordial gas into stars. Now, in protoplanetary disks swirling around protostars, the disk gas orbits slower than the protoplanets, which must stream through the disk gas. For, the disk gas is affected by pressure (and viscosity). Perhaps, then, something similar happens in the galactic disks of spiral galaxies? Perhaps gas orbits central SMBH more slowly than (newly formed) stars? Perhaps "gas is slow, stars are fast" ? Cp.: http://phys.org/news/2011-06-spitzer-distant-galaxies-grazed-gas.html
EquisDeXD Posted October 21, 2012 Posted October 21, 2012 (edited) I am sorry but I don't seem to be able to understand what points you are trying to make. Maybe I wasn't understanding the point you were trying to make. Were you saying that scattering from gas would cause certain objects to not be visible, and thus we wouldn't measure as much mass because the light didn't reach us? Because there's also different frequencies of light which filter through different materials gas. Infra-red light for example passes through most of the interstellar dust directly to the telescope, which is why scientists use it to peer into the center of the galaxy and look at Saggitarius A. With different combinations of light filters, they can determine the amount of stars using infra-red rays, and determine the amount of stellar gas using optical and ultra-violet rays, but despite that we still don't have an explanation for the apparent mass and lack of visible matter, there has to be matter that exists which is not made out of the same stuff as stars or gas, like singularities and neutronium at least, and/or dark matter. Edited October 22, 2012 by EquisDeXD
Spyman Posted October 22, 2012 Posted October 22, 2012 Maybe I wasn't understanding the point you were trying to make. Were you saying that scattering from gas would cause certain objects to not be visible, and thus we wouldn't measure as much mass because the light didn't reach us? No, CaptainPanic asked: If there is a halo surrounding us, don't we misjudge the distance, because part of the light is absorbed by that halo? Just like your visibility is reduced in fog? To which I replied: I am not an expert either but if our visibility is reduced due to a halo surrounding us then shouldn't scattering of light blur the images? What I meant was that IF our visibility is highly reduced as in a fog, then it is possible that we could be able to notice a blurring.
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