Baby Astronaut Posted December 31, 2008 Share Posted December 31, 2008 (edited) When they show a diagram of the observable universe or the cosmic microwave background, are they showing the observable universe as we see it now, or do they calculate where everything is supposed to be today and give us the projected approximations in the image? (Edit -- in other words, do they map the universe in "real time" or in observational/past time?) And if they don't usually show us the new projected locations of all cosmic bodies, is there anyone or a group that has created (or attempted) such a map? Edited December 31, 2008 by Baby Astronaut Link to comment Share on other sites More sharing options...
Klaynos Posted December 31, 2008 Share Posted December 31, 2008 They map what we see when we look at the skies. There's no moving positions or anything, there would be no point. Link to comment Share on other sites More sharing options...
Baby Astronaut Posted December 31, 2008 Author Share Posted December 31, 2008 Sure there would be a point. To look at our universe in real time, how it exists today. Otherwise we're just glancing at history instead of the modern universe. At least where concerns positions of galaxies, super clusters and how far everything has really traveled due to cosmic expansion. Link to comment Share on other sites More sharing options...
Martin Posted December 31, 2008 Share Posted December 31, 2008 (edited) Sure there would be a point. To look at our universe in real time, how it exists today. Otherwise we're just glancing at history instead of the modern universe. At least where concerns positions of galaxies, super clusters and how far everything has really traveled due to cosmic expansion. In general terms I kind of sympathize, but you may have gotten off on the wrong foot by mentioning the 2D maps of the sky (e.g. the CMB maps referred to). 2D sky maps wouldn't be changed by expansion. Maybe you should specify that you would like to see 3D maps of chunks of space, constructed to show realtime positions. there is also the issue of scale. On a small local scale, with individual stars, they have their own individual motions. And astronomers could determine where they are today and plot that. The map wouldn't look very different, I suspect, because the motions are so small. But one could do it. Thing is, you couldn't show that on the same 3D map that shows clusters of galaxies because the scale is so different. If a galaxy is a dot, then how do you show stars? Maybe what you are talking about would turn out to be an interactive map, where you could zoom, and change scale, and change your standpoint, view things from a different angle. Anyway yes it would be nice to have control of time and scale in the maps one uses. I'm not clear on how the information would be presented. It's not immediately obvious to me what the format would need to be, in order to make for a significant benefit. Maybe you have some specfic ideas? Edited December 31, 2008 by Martin 1 Link to comment Share on other sites More sharing options...
snp.gupta Posted January 1, 2009 Share Posted January 1, 2009 In general terms I kind of sympathize, but you may have gotten off on the wrong foot by mentioning the 2D maps of the sky (e.g. the CMB maps referred to).2D sky maps wouldn't be changed by expansion. Maybe you should specify that you would like to see 3D maps of chunks of space, constructed to show realtime positions. there is also the issue of scale. On a small local scale, with individual stars, they have their own individual motions. And astronomers could determine where they are today and plot that. The map wouldn't look very different, I suspect, because the motions are so small. But one could do it. Thing is, you couldn't show that on the same 3D map that shows clusters of galaxies because the scale is so different. If a galaxy is a dot, then how do you show stars? Maybe what you are talking about would turn out to be an interactive map, where you could zoom, and change scale, and change your standpoint, view things from a different angle. Anyway yes it would be nice to have control of time and scale in the maps one uses. I'm not clear on how the information would be presented. It's not immediately obvious to me what the format would need to be, in order to make for a significant benefit. Maybe you have some specfic ideas? May I add a point here??? (See the boldface above) No part of sky CMB map is similar to any other part of sky. As one of our friend suggested, for CMB, one can give an analogy like some kind of fog. We see - well- fog and stare inside it. After some training of the eyes we see the faint contours of our neighboring house. It is simply because the fore ground radiation depends on the different sources like stars, Galaxies and astronomical bodies. They vary from place to place. The radiation differs depending on foreground. That’s why we see contours, what do you say? Link to comment Share on other sites More sharing options...
Baby Astronaut Posted January 1, 2009 Author Share Posted January 1, 2009 Would a moderator please close the thread? Or delete it? I'm starting another one. I knew it was a mistake to include the CMB but neglected to remove it before hitting the post button. I'll just rephrase the question elsewhere so no one begins with the wrong impression on the first post here. Link to comment Share on other sites More sharing options...
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