Rosa Rubicondior: Refution Creationism - Waving Goodbye To Childish Superstitions

The Milky Way.

ESA - Gaia discovers our galaxy’s great wave

Astronomers, using data from the European Space Agency's (ESA's) Gaia space telescope, have discovered a vast wave passing through the Milky Way Galaxy, spreading out from the centre like ripples in a pond but with a wave length of about 13,000 light-years. The origins of this wave are still a matter for speculation and will require further data before they can be determined.

With evidence such as this, only a creationist eager to prove that they’re too tough to be persuaded by mere facts could believe that the description of the universe in Genesis is a complete and accurate account of reality, far surpassing in accuracy and reliability anything that science can produce. And only someone desperate to believe it could imagine that the description in Genesis is some sort of metaphor or allegory with a deeper meaning, rather than a hopelessly bad guess made by ignorant Bronze Age storytellers.

How our knowledge of the Milky Way has improved over time is a measure of the extraordinary progress cosmology has made in just over a century. When Albert Einstein was writing his papers on relativity, it was widely assumed that the Milky Way *was* the universe. Then, about a hundred years ago, astronomers discovered that the galaxy rotates around a centre, and in the 1950s it was found to be warped. Meanwhile, Edwin Hubble demonstrated that the Milky Way is just one of billions of galaxies and that the universe is vastly larger than previously imagined — and still expanding. Now, we can detect the motions of stars within the galaxy that reveal this ripple spreading outwards.

Meanwhile, Bible literalists are stuck with an understanding that has not advanced since the Bronze Age, based on a book which says Earth is fixed and immobile at the centre of everything, and that the stars are tiny lights attached to a dome over the world. Until around 600 years ago, the Church vigorously persecuted anyone who argued otherwise, desperate to preserve its power based on the claim that its holy book was the inerrant word of God. It was not until 1992 that the Catholic Church finally admitted that Galileo Galilei was right — 41 years after it had accepted the evidence for the Big Bang. Such is the muddle that religious dogma based on ancient, evidence-free superstitions creates.

The news of the wave spreading across the Milky Way comes in the form of a paper in the journal Astronomy & Astrophysics and a news release from ESA.

Gaia discovers our galaxy’s great wave
Our Milky Way galaxy never sits still: it rotates and wobbles. And now, data from the European Space Agency’s Gaia space telescope reveal that our galaxy also has a giant wave rippling outwards from its centre.
We’ve known for about a hundred years that the galaxy’s stars rotate around its centre, and Gaia has measured their speeds and motions. Since the 1950s, we've known that the Milky Way's disc is warped. Then in 2020 Gaia discovered that this disc wobbles over time, similarly to the motion of a spinning top.

And now it has become clear that a great wave stirs the motion of stars in our galaxy over distances of tens of thousands of light-years from the Sun. Like a rock thrown into a pond, making waves ripple outwards, this galactic wave of stars spans a large portion of the Milky Way’s outer disc.

The Milky Way's great wave illustrated.

The unexpected galactic ripple is illustrated in this figure above. Here the positions of thousands of bright stars are shown in red and blue, overlaid on Gaia’s maps of the Milky Way.

In the left image, we look at our galaxy from ‘above’. On the right, we see across a vertical slice of the galaxy and look at the wave side-on. This perspective reveals that the ‘left’ side of the galaxy curves upward and the ‘right’ side curves downward (this is the warp of the disc). The newly discovered wave is indicated in red and blue: in red areas, the stars lie above, and in blue areas the stars lie below the warped disc of the galaxy.

Even if no spacecraft can travel beyond our galaxy, Gaia’s uniquely accurate vision – in all three spatial directions (3D) plus three velocities (moving towards and away from us, and across the sky) – is enabling scientists to make these top-down and edge-on maps.

From these, we can see that the wave stretches over a huge portion of the galactic disc, affecting stars around at least 30–65 thousand light-years away from the centre of the galaxy (for comparison, the Milky Way is around 100 thousand light-years across).

What makes this even more compelling is our ability, thanks to Gaia, to also measure the motions of stars within the galactic disc. The intriguing part is not only the visual appearance of the wave structure in 3D space, but also its wave-like behaviour when we analyse the motions of the stars within it. This observed behaviour is consistent with what we would expect from a wave.

Eloisa Poggio, first author
Istituto Nazionale di Astrofisica (INAF), Italy.
[Eloisa Poggio]… led the team of scientists that discovered the wave.

The Milky Way’s great wave in motion

The motions of the stars are made visible with the white arrows in the edge-on image of the Milky Way above. What can be noticed, is that the wave pattern of the vertical motions (represented by the arrows) is slightly shifted horizontally relative to the wave pattern formed by the star's vertical positions (indicated by the red/blue colours).

Think of a ‘wave’ performed by a crowd in a stadium. Given that galactic timescales are much longer than ours, imagine seeing this stadium wave frozen in time, much like how we observe the Milky Way. Some individuals would be standing upright, some would have just sat down (as the wave passed), and others would be preparing to stand up (as the wave approaches them).

In this analogy, the people standing upright correspond to the regions coloured in red in our face-on and edge-on maps. And, if we consider motions, the individuals with the largest positive vertical motions (represented by the largest white arrows pointing upwards) are those who are just starting to stand up, ahead of the incoming wave.

Eloisa and her colleagues were able to track down this surprising motion by studying the detailed positions and movements of young giant stars and Cepheid stars. These are types of stars that vary in brightness in a predicable way, which can be seen by telescopes like Gaia over large distances.

Because young giant stars and Cepheids move with the wave, the scientists think that gas in the disc might also be taking part in this large-scale ripple. It is possible that young stars retain the memory of the wave information from the gas itself, from which they were born.

Scientists do not know the origin of these galactic shakes. A past collision with a dwarf galaxy could be a possible explanation, but they need to investigate further.

The warped galactic disc of the Milky Way wobbles like a spinning top.

The great wave could also be related to a smaller-scale rippling motion seen 500 light-years from the Sun and extending over 9000 light-years, the so-called Radcliffe Wave.

However, the Radcliffe Wave is a much smaller filament, and located in a different portion of the galaxy’s disc compared to the wave studied in our work (much closer to the Sun than the great wave). The two waves may or may not be related. That’s why we would like to do more research.

Eloisa Poggio.

The upcoming fourth data release from Gaia will include even better positions and motions for Milky Way stars, including variable stars like Cepheids. This will help scientists to make even better maps, and thereby advance our understanding of these characteristic features in our home galaxy.

Johannes Sahlmann, Not an author of the paper.
ESA’s Gaia Project Scientist.

Publication:
E. Poggio, S. Khanna, R. Drimmel, E. Zari, E. D’Onghia, M. G. Lattanzi, P. A. Palicio, A. Recio-Blanco and L. Thulasidharan
The great wave - Evidence of a large-scale vertical corrugation propagating outwards in the Galactic disc.
Astronomy & Astrophysics, 699 (2025) A199; DOI: https://doi.org/10.1051/0004-6361/202451668

Of course, the astronomers at ESA never set out to make the authors of Genesis look like scientifically illiterate, superstitious mythmakers — that’s merely an incidental consequence of revealing the facts and allowing us to compare them with what those ancient storytellers invented. What it does highlight, however, is just how far human understanding of the universe has advanced in the 3,500–4,000 years since the creation myths in the Bible first emerged from the campfire tales of tribal pastoralists in the ancient Middle East — in what Christopher Hitchens memorably called "the fearful infancy of our species."

It takes a remarkable degree of wilful blindness to ignore that reality and dismiss centuries of scientific progress as either illusory or the work of some malevolent force, all while reaping the benefits of a modern, science-based civilisation. It takes an extraordinary lack of self-awareness to use a computer and the Internet to proclaim that science doesn’t work.

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