A Map of the Universe, 10 Years In the Making 130
gabbo529 writes "Astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) have created a map of the universe called the 2MASS Redshift Survey. The astronomers put in 10 laborious years in creating the map and it is what they call the most complete 3-D map of the local universe (out to a distance of 380 million light-years) ever created. 2MASS Redshift Survey extends closer to the Galactic plane than any other map of the universe before it; the region is generally obscured by dust."
So... (Score:5, Funny)
Re:So...not ten years out of date (Score:5, Insightful)
The map is not ten years out of date.
It is 380 million years out of date, in places.
Instead, it took ten years to find out how out of date it really was.
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I was going to say something similar, but you beat me to it. Yeah... time, space and the speed of light are all to be figured. For all we know, none of those stars and galaxies even exist at this moment. They could have been destroyed to make way for some sort of space highway project already. (Don't forget your towel!)
In some respects, the idea of mapping the known universe is like mapping out a splash of water captured in super slow motion. It's all very interesting, but by the time you might be able
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How much could the universe have changed in 380 million years.
Oh... ya... An awful lot. This [youtube.com] is what was observed from a single location, looking at a very small portion of the sky (approx 1/10,000), looking for a specific type of supernova. In 3 years, in 1/10,000th of the sky, they identified 241 new supernovas.
I know you can't extrapolate that tiny sample set out to the whole period. That would be far too easy. (241 * 10000) * 380 million years. Nope, that'd b
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I wouldn't know. I never used NC. I was always very happy with my copy of DesqView, with 3 windows running my BBS, and the fourth for whatever I wanted to do. Oh, the good old days. :)
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No, their high resolution picture is a (relatively) low result 2d single plane map. And honestly, I can't even begin to guess at the distances. I'll assume that's what the red shift color scale is, but then that indicates that the colors of the stars they represent.
I'd assume that we (earth) is the center of the universe, as it's what we can see from here. The coordinates are nice and all, but I don't have a frame of reference to guess which direction is what.
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I'd love too see that done in Universe Sandbox.
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Right, but a mess of colors on a 2d image then doesn't give us an indication of what color the planets are, nor can we easily identify distance.
They have the source data that generated the image. There's no way any of us (ok, most of us) are going to try to reverse engineer the list from the image. Even if we did reverse engineer direction and distance, that still doesn't give us indication of motion in the galaxies or around other bodies, but I guess we could at least find t
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That plot is absolutely rubbish. I do know what redshift is, I do know the coordinates they're using on the plot, and I even understand why they might want to do a 2D plot (because that's basically we see from Earth; everything is projected onto the celestial sphere; and if you converted to distances you'd be making a lot of model-specific assumptions). But that plot is still absolutely rubbish. Surely they can do better than that? At the very least they could do a 3D plot in redshift-space. That's not hard
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Ya, I just re-read what I wrote. I can't believe I wrote planets. I frequently am talking to my girlfriend while I'm writing, so sometimes I type what I'm saying rather than what I'm thinking. :)
Most of what we're seeing are galaxies, supernovas, and even galactic clusters.
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Oh I totally agree with you. At the least they could have released a 3D chart with galactic coordinates and redshift as the axes, even if they didn't convert to distances -- or converted to distances and printed the caveats about that conversion being model-dependent. It woudl really help visualisation. I imagine it'll happen soon though; it didn't take long for someone to import the SDSS data (release 1 or release 3, last time I checked, unless it was actually 2dF) into Celestia and someone will do the sam
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Try NASA/IPAC Infrared Science Archive, for NASA's Infrared and Submilimeter Data [caltech.edu] all of the data is there, 277 columns by a little over 257 million rows. It should be trivial to write a Perl script to massage the data and feed it into POVRAY for the 3D representation, might take quite a while to get your output.
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Ohhh, the evil you have brought upon us..
I just built out two Linux servers, with AMD Phenom II X6 1090T Processor and 16GB RAM and 16TB RAID5. Those are office servers, so they're only busy during the week. Then a Windows workstation, AMD Phenom II x4 955 running at 3.8Ghz with 8GB RAM and a 2TB RAID 0.
Ya, I'm ready to do some rendering... I'll have until I'm awake enough to be able to read all the words on their page. Parts of my brain that understand wri
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interestingly a SMP/multicore version of POVRAY is in beta testing, I threw that out there as an indigestable cookies for the trolls. A lot of trolls whine and cry over source code or original data being unavailable without a snowball's chance in hell of doing anything with it if it were, then someone serious sees it as a challenge
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Its what ten years out of date? :P
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It's rubbish. If this was any good I could zoom in down to streetlevel view.
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Eve takes place in one galaxy, this is the universe.
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Kind of like long range scans playing Star Trek on a line printer.
Redshifts, red = moving away and blue = closer? (Score:2)
If that is correct, does green mean on the same vector?
Also, it would appear that the universe within 380 millions years was not expanding but contracting, at least it appears to have more blue to me than red.
What would be neat is if they re-did the map with positions adjusted for the "redshift" where you could compare by toggling quickly back and forth, to get an idea of how much difference there is between what we see due to speed of light and the time for it to hit our eyes from the star, and what we bel
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blue = closest, red = furthest, green = in between. They're color-coding distance, not red shift per se.
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Well, not really. The press release talks about distances (hence that 380m light years bit) but the plot itself is marked up in redshifts. Then they're just colour-coding for those.
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Also, it would appear that the universe within 380 millions years was not expanding but contracting, at least it appears to have more blue to me than red.
Just a guess: that might be the gravitationally-bound local group. We're in for a collision with Andromeda in a few billion years!
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Well apparently he can't read yet wants others to. (Typical coward...) Just because it's called redshifted, it often is used to describe a shifts period, unless you need to be specific and then you might say blue. Don't blame me, it's like crackers being called hackers. Related yes, same thing no, but that is how it is used.
While of course rarer, I am pretty sure there are objects moving toward the Milky Way. IF that isn't represented, it should be noted. Perhaps it was in that key, but sparse keys will lea
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Of course there are objects moving towards us, quite a lot of them when you look towards the Virgo supercluster (because we're falling into it). However they tend to be extremely nearby, as far as cosmological distance scales go. The universal expansion is known as the "Hubble flow", and it grows rapidly as you look further and further away from us, and quickly swamps any local motion (known as "peculiar motion", although the terminology is imprecise and sometimes that only refers to the motion as projected
There be Bogs (Score:1)
Sweet! (Score:2)
Schrodinger's Dot (Score:1)
or, maybe not
Center of the universe (Score:2)
Boring... (Score:1)
Celestia? (Score:3)
We need to see this in Celestia!
Does the internet accept the challenge?
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Damn, you beat me to that comment!
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In order to make this happen, I hope to see more volumetric effects to make those nebulae pop out. Celestia with add-ons is amazing, but it can be so much more.
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Then, we'll just have to wait a bit more for streetview on Epsilon Eridani c.
Weird spiderweb/neuron concentrations (Score:2)
It's a little hard to tell from these images, but the videos I saw on a documentary show really well a concentration along web-like lines. Maybe neural connections are a better analogy. Pretty amazing that the universe isn't a homogenous mixture of galaxies.
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It is isn't it? Matter almost seems to have this attractive force.... ;) But yes, it is weird and interesting, but other phenomena has exhibited similar "web like lines" as you describe it, due to an attractive pull. I do believe that usually a lack of opposing force or push (like the space vacuum for stars, i.e. pull unimpeded) helps to facilitate.
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Here are good starting points on voids [wikipedia.org] and filaments [wikipedia.org].
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....it's a tenet of cosmology (which seems more or less justified) that if you look on large enough scales it *is* a homogeneous mixture of galaxies. If it wasn't, our cosmological models would be pure baloney. (The interesting part comes when you try and actually prove that this tangled network of strings and voids and filaments and massive clumps of superclusters averages out to a homogeneous universe, given that we can't define a meaningful average in general relativity. It seems very likely, especially
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Err, thanks.
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I would love to see an animated gif of this sphere rotated so we could see the filaments. Some small amount of post processing that would elongate the dots along the filament lines would be a tremendous help.
Obligatory Steven Wright paraphrase (Score:2)
I have a map of the Universe, it's actual size. It says One Megaparsec = One Megaparsec.
Or even worse, it says One Kessel Run = Less Than Twelve Parsecs.
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Why would a map show a "run" (course) in distance (parsecs) when that unit of measurement is obviously used in a way such as a car's 0-60 speed(but in this case distance instead of speed)?
Blank spot (Score:1)
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Obscured by the dust in our own galaxy.
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As mentioned by the summary. Etc.
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that's the effect of this mess: http://apod.nasa.gov/apod/ap100709.html [nasa.gov] except at a different wavelength
Earth's faith is doomed... (Score:2)
Observations indicate that the map must be wrong (Score:2)
To construct the map, the standard assumption that red shift is proportional to distance was made. However, a growing body of observational evidence indicates that there are further sources of red shift not related to distance. This implies that the map must be wrong since it is based on an incomplete interpretation of red shift measurements.
For a good documentary where the mentioned growing body of evidence is being discussed by astronomers and astrophysicists see "The Universe - Cosmology Quest". A torr
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..... no.
that map is in redshift space. did you not notice the colour-coding at the bottom is in redshift? they've not converted it to distances at all. the most they might have done is removed objects with redshifts 0.01 or 0.05 or something like that.
try and look at what's going on before you sit there banging some tired old drum.
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You are trying to make a difference where there is none on two accounts. Firstly, taking redshift and using it as a spatial dimension for a map implies a distance interpretation or, if you wish, a uni-variate spatial interpretation of redshift. An this interpretation is obviously is wrong if, as the observational evidence indicates, there are objects with high redshift co-located with objects that have much lower redshift: the mapping is then projecting two co-located objects on different parts of the map y
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What you're doing is interpreting redshift as distance and then attacking that. In the science that will be done on this dataset then, yes, the cosmologists will employ a background model and convert the redshifts to "distances" (if you like) to do an analysis. Of course they will; that's what you have to do. If you want to apply your own pet model to it the data is freely available. Go ahead and knock yourself out. No-one's going to stop you.
But *that plot that they put out*, I mean *that one we're talking
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Well, no, not my interpretation, theirs. Quoting:
A press release like that implies a spatial interpretation: "map", '3-D", "distance"...
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That's why I emphasised "the plot we are talking about", and commented that in the press release they'd interpret it in terms of a simple model for the general public.
"But *that plot that they put out*, I mean *that one we're talking about* is in redshift space."
"in the press release obviously they're going to simplify down for a general audience"
They're going to use the standard model. And like it or fucking lump it, but the standard model interprets those redshifts as evidence for a universal expansion, w
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I feel a bit I'm talking to a brick wall here. Probably my fault getting into a more extended conversation than the original point, and not making that clear enough.
Quoting my reply to the original poster,
"The point was that *THAT PLOT THAT THEY PUT OUT* is, in contradiction to your statements "To construct the map, the standard assumption that red shift is proportional to distance was made" and "taking redshift and using it as a spatial dimension for a map implies a distance interpretation"."
That was my on
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When they interpret the map, they're going to interpret the redshift as a measure of distance. This is because they're interpreting it through the standard (big bang/Robertson-Walker) model of cosmology, which has that the universe expands. This imparts a gravitational redshift on propagating light rays -- basically the wavelength is stretched as the universe expands, which makes sense.
The analysis of the 2MASS data will be done (by the team themselves) within the bounds of Robertson-Walker cosmology. That'
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It's not in redshift space in the sense of a spatial dimension, the dots are just color coded on a 2-D projection. The plot appears to include all positive redshifts. Most of the redshifts are below 0.02. I don't think they are concentrating on the cosmological redshifts, rather all reasonably bright, low redshift galaxies - the point is to get the observational data, others can crunch and interpret it as desired.
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"It's not in redshift space in the sense of a spatial dimension"
that's what i've been trying to say, too... they just plotted RA vs declination and then redshift on a colour scale.
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taking redshift and using it as a spatial dimension for a map implies a distance interpretation
Yes it does, but since they haven't done that all you have is a strawman.
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The map is 2-D, not 3-D, the redshifts are indicated only as colors, no distance conversion has been made. All galaxies observed with a positive redshift were included, most of the dots are galaxies with redshifts under 0.02. The greatest redshifts on the map are around 0.07. This is a tiny fraction of the largest observed redshifts, less than 3%, and the volume is likely to be correspondingly small compared to the volume of the universe (something like 1/50000 of the universe's volume if the redshift-dista
Why is the equator empty? (Score:2)
The map [harvard.edu] seems to be almost empty at the equator.
I'm sure there's a logical explanation, but I've no idea what it is. Anyone care to enlighten me?
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This map is in galactic coordinates, this means our own galaxy runs along the equator of this map. It is also obscuring the view, hence the lack of data in this area of the map.
You are here (Score:1)
"out to a distance of 380 million light-years" (Score:3)
Only 380? That's a pity. An old friend that lives 380,000,006 light years away is always inviting me over but there's no way I'd find his place without a map.
It's probably not that far as-the-crow-flies, but light takes a longer, curvy path.
How handy... (Score:1)
I might suggest taking that map along if you experiment with wormhole or quantum accelerator technologies. That is only if you get lost and have any desired to return home. Then again, torch it if you think your about to be captured. After all Hawkins thinks they will be hostile when "they" get here. He also thinks there is no God. I think he suffers from "angry-cripple-syndrome" where the sufferer's point of view is tainted by his miserable existence, hence his bleak outlook.
Anyway..hows this load into my
Random colors on a black background (Score:2)
is all it is
How can I put this map into my GPS? (Score:1)
You know its big when . . . (Score:4, Insightful)
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2MASS publish their full catalogue on their FTP server. It's painful to download, even on broadband.
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if you want to redo just the redshift plot, you don't want 2MASS. see http://science.slashdot.org/comments.pl?sid=2189074&cid=36259732 [slashdot.org]
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It's a lot more useful to be in redshift space than it would be in "real" space. To swap it to real space you have to make a lot of assumptions about the nature of the universe, and you get out something that may or may not actually correspond to the actual distribution. Redshift space is distorted by other effects, particularly for galaxies nearby where the Hubble flow is weak and peculiar motions strong (the extreme example being the Andromeda galaxy with its strong blue-shift given that it's flying strai
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So for the southern hemisphere you want to fetch the 6dF catalogue, for the northern, zcat.
The best to get those is using vizier, for instance as two tab-separated file.
zcat -- http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=VII/193 [u-strasbg.fr] -- select zcat -- select column vh only, this is recessional velocity in km/s
6dF -- http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=VII/249 [u-strasbg.fr] -- select spectra -- select column z only, this is redshift
You will find conversions between distance, velocity and redshift z in http: [wikipedia.org]
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Some of those stars must have monsters wielding plasma rifles, right?
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I mean, for fuck's sake, give me the vector coordinates and I'll make a shit load of files for everyone who wants to view the data in actual 3D -- .blend, .obj, .3ds and several levels for Alien Arena. Hell I have a script that already does this for point clouds (esp. for Kinect) that I can adapt in about 10 minuets. WAD?! (where's all the data?)
Oh sure YOU created a 3D map -- please, no -- you measured the 3D coordinates. Give them to us so we can actually see it -- Oh, I forgot, the purpose of today's research agencies and universities is to charge exorbitant fees for basic knowledge.
The bullshit 3D movies they'll come out with will pale in comparison to the crowd soured galaxy naming/classifying cross reference websites we could make -- if only they weren't Data Nazis. Of course we could suggest more red-shift surveys based on interesting imagines obtained from the Hubble and other telescopes -- Imagine being able to actually map the galaxy by virtually flying around in it, and having beautiful annotated pictures and comments appearing as you approach select parts...
I could reverse engineer their bullshit 2D map, but that would be a waste of time since they have the 3D coordinates they used to plot the map.
Knowledge like this is only of value if it's made free (as in freedom).
word.
Re:Asshats. Where's the 3D? (Score:5, Informative)
GP misunderstands problem, but it's real (Score:1)
While the GP misdiagnoses it, there is a problem.
Consider:
() The scientific literature is still far from being all open access.
Astronomy is great, with its preprint culture. Education research is surprisingly among the worst. "Oh, you wish to {teach your child, edit wikipedia, blog about} _physics_? That will be $$ per year or $$ per article here you wish to skim. Oh, math too? That will be..." Also, people are more likely to hear about papers in prestige journals, which are more likely to be paywalle
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Enjoy [caltech.edu]
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that's the view as seen from earth. so we can't be represented on that map at all -- that's what we see surrounding us, except that the celestial sphere has been mapped onto a 2d plane. you can transform that map back and put it on a sphere, and then yes, we'd be in the centre of the sphere.
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.
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under the assumption that that's an honest question, no, not really, unless you're seriously going to complain that north is "up". that plot is in galactic coordinates, which are based on the sun's position in the galaxy. http://en.wikipedia.org/wiki/Galactic_coordinate_system [wikipedia.org]