cfa 3d map

Take a Flight Through Our Universe, Thanks to New 3-D Map of the Sky

9 Aug , 2012 by

The Sloan Digital Sky Survey III (SDSS-III) has released the largest three-dimensional map of massive galaxies and distant black holes ever created, and it pinpoints the locations and distances of over a million galaxies. It covers a total volume equivalent to that of a cube four billion light-years on a side.

A video released with the map takes viewers on an animated flight through the Universe as seen by SDSS. There are close to 400,000 galaxies in the animation, which places zoomed-in images of nearby galaxies at the positions of more distant galaxies mapped by SDSS.

“We want to map the largest volume of the universe yet, and to use that map to understand how the expansion of the universe is accelerating,” said Daniel Eisenstein (Harvard-Smithsonian Center for Astrophysics), the director of SDSS-III.

The map is the centerpiece of Data Release 9 (DR9), which publicly releases the data from the first two years of a six-year survey project. The release includes images of 200 million galaxies and spectra of 1.35 million galaxies. (Spectra take more time to collect than photographs, but provide the crucial third dimension by letting astronomers measure galaxy distances.)

“Our goal is to create a catalog that will be used long after we are done,” said Michael Blanton of New York University, who led the team that prepared Data Release 9.

The release includes new data from the ongoing SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), which will measure the positions of massive galaxies up to six billion light-years away, as well as quasars – giant black holes actively feeding on stars and gas – up to 12 billion light-years from Earth.

BOSS is targeting these big, bright galaxies because they live in the same places as other galaxies and they’re easy to spot. Mapping these big galaxies thus provides an effective way to make a map of the rest of the galaxies in the universe.

With such a map, scientists can retrace the history of the universe over the last six billion years. With that history, they can get better estimates for how much of the universe is made up of “dark matter” – matter that we can’t directly see because it doesn’t emit or absorb light – and “dark energy,” the even more mysterious force that drives the accelerating expansion of the universe.

“Dark matter and dark energy are two of the greatest mysteries of our time,” said David Schlegel of Lawrence Berkeley National Laboratory, the principal investigator of BOSS. “We hope that our new map of the universe can help someone solve the mystery.”

This release is being issued jointly with the SDSS-III Collaboration.

All the data are available now on the Data Release 9 website at http://www.sdss3.org/dr9. The new data are being made available to astronomers, as well as students, teachers, and the public. The SkyServer website includes lesson plans for teachers that use DR9 data to teach astronomy and other topics in science, technology, and math. DR9 data will also feature in a new release of the Galaxy Zoo citizen science project, which allows online volunteers to contribute to cutting-edge astronomy research.

Image caption: This is a still image from the fly-through video of the SDSS-III galaxies mapped in Data Release 9. Credit: Miguel A. Aragón (Johns Hopkins University), Mark SubbaRao (Adler Planetarium), Alex Szalay (Johns Hopkins University), Yushu Yao (Lawrence Berkeley National Laboratory, NERSC), and the SDSS-III Collaboration

Source: CfA

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Zoutsteen
Member
Zoutsteen
August 9, 2012 7:29 AM

Like an angry snowstorm, but one you enjoy watching.

Mike Petersen
Guest
Mike Petersen
August 9, 2012 8:34 AM

With each spot of light in this video representing a galaxy as large (on average) as our own, it only takes a few seconds to realize just how immense space really is.
Impressive.

HeadAroundU
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HeadAroundU
August 9, 2012 12:58 PM

This is pretty impressive.

Lawrence B. Crowell
Member
Lawrence B. Crowell
August 9, 2012 1:46 PM
The SDSS looks out to where the red shift factor is z = .15. This means the galaxies are moving out at v = zc = 4.5×10^4km/s. If we use the Hubble relationship v = Hd, for H = 74km/sec/Mpc (7.4×10^{-5}km/s/pc or 2.27×10^{-5}km/s/ly) we can compute the distance out with d = v/H, d = (4.5×10^4km/s)/(2.27×10^{-5}km/s/ly) = 1.98×10^9ly. This is a fraction of the distance out to the cosmological horizon ~ 1.2×10^{10}ly. The CMB is around 4.5×10^{10}ly and the particle horizon is about 5×10^{11}ly. The cosmological horizon is the limit beyond which we can’t send a message to a galaxy beyond it. The particle horizon is the limit beyond which we can observe the universe. Consequently this video… Read more »
henk
Member
henk
August 9, 2012 2:34 PM

What a great video. How many galaxies are there in our universe ? Could we find a way to know something like that. I really do not know

bugzzz
Member
bugzzz
August 9, 2012 4:08 PM

I think I read the current estimate is about 100 billion galaxies. Each with about 100 billion stars. Then what if there’s more than one universe?? smile

Philip Wilson
Guest
August 9, 2012 5:06 PM

That is the visible universe. We don’t know what portion of the universe we live in (never mind others) the light cone limited visible universe comprises.

Tony Nelson
Guest
August 9, 2012 4:08 PM

It would be interesting to start out zoomed in on our own galaxy, with a caption that says “You are here”, so we can see where we are with respect to all the other galaxies.

Russ Gibbons
Guest
August 9, 2012 4:22 PM

How much time (in billion year units) would it take to make the journey shown in the video? If traveling near the speed of light.

Aqua4U
Member
August 9, 2012 5:23 PM

Who said it’s impossible for mankind to travel faster than the speed of light? The Sloan Digital Time Machine proves that it IS possible! At least, in the mind’s eye…. Nice!

Tim OBrien
Guest
Tim OBrien
August 12, 2012 6:35 PM

yup, needs a ‘You are here’ sign….

nuoji
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nuoji
August 15, 2012 1:30 PM

tinyurl.com/cyk9xz2
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