23 Degrees buzz of the week: Astronomers reveal 3-D map of local universe
| 18:31 UK time, Thursday, 26 May 2011
Just like we were excited to hear about NASA STEREO satellites capturing 3D images of the Sun, back in february - recent developments in the study of the universe has got us talking about astronomy developments once again.
Image © CfA
It took over 10 years to complete but the 2MASS Redshift survey (2MRS) conducted by the Harvard-Smithsonian Center for Astrophysics, was revealed yesterday at the 218th meeting of the American Astronomical Society, by Karen Masters (University of Portsmouth, UK).
CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.
Our fascination with astronomy, like with many other people, couldn't have been put more precisely than by Karen's statement at the press release - "I think it speaks to our desire to understand our place in the universe...I wouldn't be happy if we didn't have a complete map of the Earth. It's nice to have a complete map of where we live."
(From CfA press release)
The 2MRS mapped in detail areas previously hidden behind our Milky Way to better understand the impact they have on our motion. The motion of the Milky Way with respect to the rest of the universe has been a puzzle ever since astronomers were first able to measure it and found it couldn't be explained by the gravitational attraction from any visible matter.
2MRS chose galaxies to map from images made by the Two-Micron All-SkySurvey (2MASS). This survey scanned the entire sky in three near-infrared wavelength bands. Near-infrared light penetrates intervening dust better than visible light, allowing astronomers to see more of the sky. But without adding redshifts, 2MASS makes only a 2-D image.
Some of the galaxies mapped had previously-measured redshifts, and Huchra started painstakingly measuring redshifts for the others in the late 1990s using mainly two telescopes: one at the Fred Lawrence Whipple Observatory on Mt. Hopkins, AZ, and one at the Cerro Tololo Inter-American Observatory in Chile. The last observations were completed by 2MRS observers on these telescopes shortly after Huchra's death in October 2010.
The 2MASS Redshift Survey began measuring the galaxies' redshifts, one by one, using two telescopes in Arizona and Chile. A galaxy's light is redshifted, or stretched to longer wavelengths, by the expansion of the universe. The farther the galaxy is from Earth, the greater its redshift, so redshift measurements yield galaxy distances - the vital third dimension in a 3-D map.
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