Talk about your 40-foot perspective: An international team of researchers has put together an absolutely brilliant 3D video map of the nearby universe out to a distance of 300 million light-years. The video is a not-so-subtle reminder of how freakishly tiny we are in the larger scheme of things.
Top image: A map showing all galaxies in the nearby universe. Each galaxy is color-coded to signify distance, with blue representing the closest and red signifying the most distant — up to 300 million light-years away. Credit: University of Hawaii.
It’s called the Cosmic Flows project and it’s an effort to map both visible and dark matter densities around our galaxy up to a distance of 300 million light-years. The map, which is presented in video format, shows our immediate intergalactic neighborhood through a series of dynamic 3D representations that are rotated, panned, and zoomed. It's the most detailed map ever created of our local vicinity, and it does a remarkable job showing us what our neighbourhood looks like.
It's important to remember that this cosmography of the local universe represents a miniscule fraction of the whole thing – about 0.32%. The observable universe is over 93 billion light-years in diameter (that's the visible universe; this is an unknown, likely infinitesimal, fraction of “the whole thing”). So as humbling as this is, the bigger picture is more daunting, still. (Then again, perhaps you're the kind of person who finds the Universe inspiring. Which, how can we blame you, really?)
The video is over 17 minutes long, but don't let that put you off. Things pick up quickly after the 1:15 mark.
The video map was compiled by Hélène Courtois, Daniel Pomarède, R. Brent Tully, Yehuda Hoffman, and Denis Courtois. "The complexity of what we are seeing is almost overwhelming," says Courtois in the video.
“The ability to translate and zoom helps the viewer follow structures in three dimensions and grasp the relationships between features on different scales while retaining a sense of orientation,” write the authors in the study.
And indeed, the video map reveals a local universe filled with a complex series of clusters, filaments (massive thread-like structures that form the boundaries between large voids in the universe), and voids — those vast, empty regions of space. As for us, our Milky Way is situated within a supercluster of 100,000 galaxies.
Fascinatingly, the map also shows the distribution of dark matter and energy; dark energy is the mysterious force that’s causing the expansion of the universe to accelerate. We can’t visually see this, but scientists can deduce its presence by its effect on the motions of galaxies and stars. Dark matter constitutes about 80% of the total matter in the universe. The properties of the local universe were determined by analyzing redshift surveys and measurements of odd-ball velocities.
The video was announced last week at the conference "Cosmic Flows: Observations and Simulations" in Marseille, France. The findings are set to be published in the Astronomical Journal, but it can be read at arXiv: “Cosmography of the Local Universe.”