Where Is the Centre of the Universe?

© 2025 Kieron Conway - All rights reserved.

There are two things that can help us answer this question, although you may not be happy about the outcome. But the conclusion might cheer you up!

The ΛCDM Model

The current theory describing the history of the universe from time = 0 to the present is known as the ΛCDM (Lambda–Cold Dark Matter) model.

Λ (Lambda) refers to Einstein’s cosmological constant. It has had a checkered history (Einstein once called it his “biggest mistake” ) but it’s now back in favour, representing the effect of dark energy, the mysterious force that accelerates the universe’s expansion.

CDM stands for Cold Dark Matter: “cold” meaning that dark matter particles move at low velocities. Dark matter provides the missing gravitational mass needed to explain why the spiral arms of galaxies don’t fly apart.

The ΛCDM model is remarkably successful because it explains three key observations far better than other models. These three observations are;

1. The primordial element ratios. ΛCDM correctly predicts the proportions of hydrogen, deuterium, and helium formed in the early universe, confirmed by astronomical measurements.

   
   

2. The expansion of space.The model predicts that distant galaxies recede from us faster the farther away they are, a relationship first demonstrated by Edwin Hubble in the 1920s.

   
   

3. The Cosmic Microwave Background (CMB). ΛCDM accurately predicts the spectrum of the CMB, the afterglow of the early universe and when it occurred. This light was released about 380,000 years after time = 0, when the universe first became transparent. Those photons have travelled for 13.8 billion years, their wavelengths stretched by cosmic expansion into the microwave region. However, If you were able to hitch a lift on a CMB photon as it escaped, you would see no change in frequency or wavelength after its incredible journey to earth. The redshift is a relative effect caused by the expansion of space between the emission of the photons and our observation.

   
   

Thanks to these successes, ΛCDM is our best description of how the universe evolved from a hot, dense state, perhaps smaller than a proton, to its current vastness.

So, What Does ΛCDM Say About the Centre of the Universe?

According to the mathematics of the model, there is no centre.

What? No centre? Where’s the proof?

The proof lies in the CMB.

CMB radiation reaches Earth uniformly from all directions. NASA’s COBE satellite (Cosmic Background Explorer, launched in 1989) mapped this radiation with great precision, searching for any directional irregularities that might reveal a preferred point in space like a centre.

The results show that the early universe was extremely homogeneous (evenly distributed) and isotropic (the same in all directions) and, on large scales, it still is today. Tiny variations in the CMB seeded the formation of stars, galaxies, and the cosmic web over billions of years.

If there had been a single “centre” where the Big Bang occurred, we would see directional asymmetries in the CMB pointing toward it. None exist: not even a hint.

What About an Edge?

Again, the mathematics, and the CMB, say no. If the universe had an edge, we would see signs of it in the background radiation, but we don’t.

So, no centre and no edge. The equations of the ΛCDM model say so, and the CMB provides the evidence to confirm it.

Conclusion

There is no single centre. However, and here's what might make you feel a bit better; every point in the cosmos can be regarded as a centre because expansion occurs uniformly everywhere.

The Universe at the grand scale

If you zoom out from your view of space and keep zooming out, you reach a point where all the discrete structures of galaxies that we can see in the night sky, vanish and we see what's called the “cosmic-fluid” at this grand scale. You lose sight of all local structures.

Every observer in the universe, no matter where they are, can zoom out to the cosmic-fluid scale and they appear to be at the centre of their observable universe.

All the tiny little “molecules” of the cosmic-fluid are moving away from each other and you are in the centre of your observable universe.

That should make you feel better!

For a brilliant visual explanation of all this, watch the Veritasium video “What Actually Expands in an Expanding Universe?” In particular, watch from 6:00 minutes to 6:59, which vividly illustrates how every observer sees themselves at the centre of expansion as they zoom out to the cosmic-fluid state of the observable universe.

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