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Ephemeris: 10/28/2025 – The structure of the universe

October 28, 2025 Comments off

This is Ephemeris for Tuesday, October 28th. Today the Sun will be up for 10 hours and 20 minutes, setting at 6:36, and it will rise tomorrow at 8:17. The Moon, 1 day before first quarter, will set at 11:38 this evening.

Dark matter makes up about 85% of all the matter in the universe, even though we can’t see it. It creates a kind of lattice on which the galaxies form. In looking out into the universe we see that there is a structure to it, not just random clusters of galaxies. The structure of the universe seems to be like a foam of bubbles where galaxies form along the intersection of these bubbles. The bubbles themselves are called voids. And with the expansion of the universe these voids are growing because space itself is expanding. So it’s not so much that the galaxies are fleeing each other, but that the voids are growing, pushing the galaxies apart. The galaxies are just going along for the ride.

The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.

Addendum

The plot shows that the galaxies are not uniformly distributed in space. They are seen to form along filaments
This is the 2 Micron All Sky Survey (2MASS) which is an infrared survey of galaxies relatively close to us in an equal area projection. Each of the 30 by 30° squares has the same area. The horizontal dark area in the center it’s called the zone of avoidance, that is where the Milky Way is blocking the galaxies behind it, due to its clouds of gas and dust. The plot shows that the galaxies are not uniformly distributed in space. They are seen to form along filaments. The plot is also color-coded from violet to red showing the red shift, which shows the galaxy’s speed of recession, and increased distance. Click or tap on the image to enlarge it.

Categories: Cosmology, Ephemeris Program, Galaxies, Universe