Space

Largest-ever 3D map of the universe reveals gigantic cosmic web

Largest-ever 3D map of the uni...
The first section of the 3D map of the cosmos, produced by DESI
The first section of the 3D map of the cosmos, produced by DESI
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The first section of the 3D map of the cosmos, produced by DESI
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The first section of the 3D map of the cosmos, produced by DESI
The 3D aspect of the DESI map can be seen in this moving image, as the view sweeps from the constellation Virgo towards Bootes
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The 3D aspect of the DESI map can be seen in this moving image, as the view sweeps from the constellation Virgo towards Bootes

Data from the Dark Energy Spectroscopic Instrument's (DESI's) first survey run has produced the largest and most detailed 3D map of the universe so far. The stunning image reveals the gigantic cosmic web of galaxies across billions of light-years – and this is only the beginning for the project.

The image contains 7.5 million galaxies within a distance of about 5 billion light-years in the direction of the constellation Virgo, with Earth located at the lower left. With the large-scale structure of the cosmos clearly visible, it’s not hard to see why it’s often referred to as the cosmic web, and there’s plenty that astronomers can learn from the data.

“There is a lot of beauty to it,” said Julien Guy, a scientist at Berkeley Lab, which manages the DESI project. “In the distribution of the galaxies in the 3D map, there are huge clusters, filaments, and voids. They’re the biggest structures in the universe. But within them, you find an imprint of the very early universe, and the history of its expansion since then.”

DESI collects detailed data on the color spectrum of galaxies, which can reveal how far away a particular galaxy is. Since the universe is constantly expanding, light from more distant galaxies becomes stretched out, so that its wavelengths are shifted further towards the red end of the spectrum. Therefore, generally speaking, galaxies that appear more red in color are farther away, and DESI uses this to build out its map in three dimensions.

The 3D aspect of the DESI map can be seen in this moving image, as the view sweeps from the constellation Virgo towards Bootes
The 3D aspect of the DESI map can be seen in this moving image, as the view sweeps from the constellation Virgo towards Bootes

Installed on the Mayall Telescope in Arizona, DESI takes its measurements using a rather unique setup. Light streams through six large lenses, and is then captured by an array of fiber optic cables controlled by 5,000 robotic positioners, which can move the cables into place with a precision to within 10 microns. From there, the light is sent into 10 spectrographs, which splits it into its constituent colors for analysis.

The current map was produced during DESI’s first seven months of operation in 2021, and it’s only just getting started. By the time its primary mission concludes in 2026, the instrument will have cataloged over 35 million galaxies, stretching as distant as 11 billion light-years. This treasure trove of data will bring to light new details about galaxies, black holes, quasars and dark energy, the mysterious force driving the expansion of the universe to accelerate.

Source: Berkeley Lab

5 comments
5 comments
MrB
Very interesting.. what are the green dots though? I get the gradual change between near and far galaxy light, but are some of them where the little green men live?

:)
FB36
IMHO, actually the key to solving DM (Dark Matter) mystery is analyzing/uncovering true physical/geometric structure of the real Cosmic Web!

I had seen some old articles from the 80s saying/claiming that Cosmic Web appears to be made of bubbles (where galaxies located on the surfaces of those bubbles)!

But the modern pictures of Cosmic Web created using computer simulations do not look like made of bubbles at all!
(I think because they are created based on gravitational collapse assumption (which is actually wrong!)!)

So which one is the true physical/geometric structure of the real Cosmic Web?

Why that is really important for solving the DM puzzle?:

Imagine that if spacetime was a superfluid & the effect of incoming Dark Energy was bubbling that superfluid!
(Similar to the surface of a boiling soup or inside of a rising dough!)
Then, realize, we would get a Cosmic Web made of bubbles & most galaxies would be located on the surfaces of those bubbles (withing denser spacetime superfluid!)!
& naturally, there would be also a small percentage of galaxies which are located away from those bubble surfaces & would look like DM free galaxies to us!
(& there would be also galaxies located in (large) bubble intersections, which would look like (unexpectedly!) having too much DM to us!)

(I think, if Cosmic Web really made of bubbles, that would also be a huge blow to the idea that DE being an intrinsic property of spacetime (like a Cosmological Constant)!)
Catweazle
Interesting, FB36...
How many dimensions do you think this physical/geometric structure of the real Cosmic Web is going to occupy?
IMO it cannot be constrained to three!
ljaques
Does anyone feel smaller after reading this article? A parsec is 3.26 light years (19 trillion miles) and the table scale here is rendered in megaparsecs.
Whooee! Dat space she is large, I ga-ron-tee!
EH
@FB36 - There are reasons to think that DM and DE will turn out to be illusions. ( https://arxiv.org/abs/0801.4089 ) The filamentary structures are likely due to large-scale magnetic fields. (Which implies currents and plasma but not the crazy "electric universe" idea that something other than fusion powers the stars.)