Hypothetical science and dark matter

Bullet Cluster, hot gas in pink, dark matter in blue

In several previous posts in this blog, I have pointed out that physicists and cosmologists frequently forget the real world and construct theories based on speculations not based on concrete data, observations, or experiments, but only in their imagination. Let’s look at a few examples:

·         Is physics losing touch with reality? In this post, published in 2017, I used as examples the various theories about multiverses, the theory of everything, and some ideas that would make it possible to build a time machine (in principle, but hardly in practice).

·         Is physics: science or literature? In this post, published in 2018, I referred to Freeman Dyson's procedure for extracting energy from stars and the idea that an advanced civilization could resist the accelerated expansion of the universe.

·         Pathological science, wishful science, or ironic science? This post, published in 2023, points out eleven cases of scientific research without experimental basis.

It often happens that these unconfirmed theories, which therefore should not be considered part of the universally accepted body of science, rely on one another, which obviously diminishes their credibility. Let's look at an example:

We know that the existence of dark matter has been proposed to explain the internal movements of galaxies and the galactic lensing effect. In both cases, applying Einstein's theory of general relativity, it seems that these galaxies should contain much more mass than they apparently do. But the existence of dark matter has not yet been experimentally demonstrated because no particles that could be part of its composition have been detected, even though it has been calculated that the total amount of dark matter in the universe should be about five times greater than that of ordinary matter, which is composed mainly by the particles we all know: protons, neutrons, electrons, and neutrinos.

The standard cosmological model assumed (without proof) the existence of dark matter and was adjusted so that the total amount of matter equaled the sum of ordinary and dark matter: about 30% of the total needed for the universe to be flat. Furthermore, the cosmological constant was reintroduced into Einstein's equation (whose effect was named dark energy) to add the remaining 70% and ensure the universe is flat and undergoing accelerating expansion, as observed in 1998. But the cosmological model does not validate the existence of dark matter and dark energy, because their existence has been postulated from the beginning.

As I mentioned in a 2016 post in this blog (Dark matter or a new theory), there is an alternative to the existence of dark matter: Einstein's theory may not be valid for galaxies. Of course, so far, no one has been able to offer a convincing alternative theory. I discussed this in a 2025 post: What’s the matter with dark matter?

A recent news report echoes a new theory that assumes the existence of dark matter (which, as I've said, is not proven) to draw conclusions about Earth's magnetic field. I'll summarize this new proposal briefly:

·         If dark matter exists, there must be a large amount of it around Earth.

·         Let's assume that dark matter has a small amount of electric charge. In that case, its presence in our vicinity should affect Earth's magnetic field, introducing a hum that should be detected by the networks of magnetometers we are using to measure it.

·         The authors of the aforementioned article, a Chinese team, have looked for this hum in the measurements of the magnetometers, but haven't found it.

·         From this, they have deduced an upper limit for the electric charge of the dark matter surrounding Earth.

Note the chain of hypotheses: a) dark matter exists, although we cannot detect it; b) it may have some electric charge; c) but it must have almost nothing, because we cannot detect its effects.

To make matters worse, another recent news report doubts of the existence of dark matter by applying the MOND theory, an alternative to Einstein's General Relativity.

The same post in Spanish

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Manuel Alfonseca