The Eye of the Universe
On Presenting the Facts of Science
The is the start of a new series of essays. We will take a break from diving ‘under the hood’ to describe how science works as a human activity. For now I am going to present a series of images that depict what we have learned, so far, and try to explain them.
Here is an image by Pablo Carlos Budassi.1 It is a logarithmic depiction of objects in the universe, centered on the sun and ending with the cosmic microwave background radiation, or CMB.
Being a logarithmic depiction, the empty space inside Mercury’s orbit is exaggerated; only sun grazing comets go there. The planets of the solar system are bunched closely together in a narrow spatial ring. The stars of the Milky Way form a ring around the solar system, with the dark ‘blind spot’ behind the galactic core. Nearby galaxies are the next ring, and the distant galaxies begin the filaments that represent the great walls of clusters of galaxies. The increasingly red color represents the redshifts of light as the observed expansion of the universe increases with distance. At the far edge is the CMB.
It almost looks like a human eye, with the pupil holding everything out to the nearby galaxies and the more distant galaxies comprising the filaments of the iris.
My main criticism of it is the depiction of the Milky Way as a whole galaxy atop the Milky Way ring, this is misleading. The planets are too large and the Oort Cloud (the source of most of our comets) is missing, but that probably can’t be helped. I also don’t understand why there is a Big Bang ring outside the CMB ring; yes, notionally it is there, but in principle we cannot observe it. It also can’t be helped that it is a two dimensional representation of the three dimensional reality.
Still, this is an awesome illustration. I am grateful that we have people who can create such things. More to come!
Postscript: it has been pointed out to me by a faithful reader that there are medieval illustrations that are strikingly similar, except that the earth is at the center. Modern astronomers sometimes simplify calculations by making the earth immobile and the sun mobile, this is termed the fictitious sun in the professional literature, for obvious reasons. So this modern illustration could have had the earth at the center, but to make sense it would have had to include a footnote explaining what the fictitious sun is.
For more on Pablo Carlos Budassi see https://commons.wikimedia.org/wiki/User:Unmismoobjetivo