Rosa Rubicondior: The Bible's Bad Science - What The Bronze Age Pastoralists Could Never Have Guessed At

Andromeda

By Kanwar Singh - Own work, CC BY-SA 4.0, Link

NASA's Hubble Provides Bird's-Eye View of Andromeda Galaxy's Ecosystem - NASA Science

Q. How do we know the Bible could not possibly have been written by the god described in it?

A. The Bible describes the god it purports to have been inspired by as all-knowing, yet there is a great deal the Bible gets wrong, and even more that is left out. Clearly, whoever wrote it was ignorant of a great deal and almost all of what little they thought they knew they got hopelessly wrong.

For example, the opening few verses of Genesis make it plain that the authors thought the Universe consisted of a small, flat planet, on which they and everything they knew about lived. This planet had a dome over it from which the sun and moon were hung and in which the stars were embedded. The Bible even described how these stars could be shaken loose during earthquakes whereupon they would fall down to Earth.

This description of the universe bears no resemblance to the real universe and is clearly a description of what someone standing on a hill in Canaan thought his universe consisted of. It could scarcely be further from the truth.

There is simply no reason for an omniscient god to have got it so wrong; it's not even of the category of a 'lie to children', like the planetary model of an atom, designed to foster understanding of some of the properties of atoms without the complication of having to understand some quantum physics. The small, flat planet with a dome over it at the centre of the universe provides nothing by way of a useful model with which we can explain observed phenomena.

It is wrong, plainly and simply, and as such has served throughout the centuries to confuse and mislead, to endarken rather than to enlighten us.

Tell me all about the Andromeda Galaxy, please. The Andromeda Galaxy (Messier 31, NGC 224) is the closest spiral galaxy to the Milky Way and the largest galaxy in the Local Group, which also includes the Milky Way, the Triangulum Galaxy (M33), and numerous dwarf galaxies.
Basic Facts

Type: Spiral Galaxy (SA(s)b)
Distance from Earth: ~2.54 million light-years (780 kpc)
Diameter: ~220,000 light-years (compared to the Milky Way’s ~105,000 light-years)
Mass: ~1.5 trillion solar masses (Milky Way is similar but uncertain)
Number of Stars: ~1 trillion (about twice as many as the Milky Way)
Apparent Magnitude: ~3.44 (visible to the naked eye under dark skies)

Structure
Andromeda is a barred spiral galaxy, though its bar is faint compared to galaxies like the Milky Way. Its structure consists of:

Central Bulge: A dense, older population of stars with a possible supermassive black hole (~100 million solar masses).
Spiral Arms: Home to younger stars, gas, and dust, actively forming new stars.
Dust Lanes: Dark filaments of interstellar dust block light from behind, visible in images.
Satellite Galaxies: Includes M32 and M110, two dwarf elliptical galaxies orbiting Andromeda.

Motion & Future Collision with the Milky Way

Andromeda is moving toward the Milky Way at ~110 km/s (68 mi/s).
Expected to collide with the Milky Way in about 4.5 billion years, likely forming a new elliptical galaxy (sometimes called "Milkomeda" or "Milkdromeda").
Despite the collision, individual stars will likely not collide due to vast interstellar distances.

Observational History

Ancient Records: The Persian astronomer Al-Sufi described it in 964 AD as a "small cloud."
Telescope Observations: Charles Messier cataloged it as M31 in 1764.
Edwin Hubble (1920s): Proved Andromeda was an external galaxy, not a nebula within the Milky Way, by studying Cepheid variable stars to calculate its distance.

Black Hole & Star Formation

Supermassive Black Hole: ~100 million solar masses, much smaller than the Milky Way’s Sagittarius A*.
Star Formation: Active in the spiral arms, fueled by interactions with satellite galaxies.

Mythology & Name

Named after the Andromeda constellation, which itself is named after the Greek mythological princess Andromeda.
The galaxy appears as a faint, elongated smudge in dark skies, best viewed in autumn in the Northern Hemisphere.

Significance in Astronomy

Andromeda provides insights into galaxy evolution, dark matter, and galactic mergers.
It allows astronomers to study a spiral galaxy similar to our own, up close.

Even when we had abandoned the childish geocentric, flat earth model, it still took us until the middle of the 20th century to fully appreciate the vastness and magnificence of the universe. Even in Einstein's day, we thought the Universe was the Milky Way galaxy; it wasn't till Erwin Hubble showed that many of the 'stars' were in fact galaxies consisting of maybe half a trillion stars, that we began to appreciate that there was so much more than we had ever imagines. We have since discovered that there are trillions of these galaxies.

Now, with the help of the Hubble and James Webb space telescopes, we are still finding out things about these galaxies by examining those closes to us such as the Milky Way's fellow galaxy, Andromeda, which, with the Triangulum Galaxy (M33), makes up a local cluster.

For example, we have recently discovered that Andromeda is not a single spiral galaxy like the Milkey way but is surrounded by a swarm of small satellite galaxes.

This is described in a recent press release from NASA and an open access paper in The Astrophysical Journal:

NASA’s Hubble Provides Bird’s-Eye View of Andromeda Galaxy’s Ecosystem
Located 2.5 million light-years away, the majestic Andromeda galaxy appears to the naked eye as a faint, spindle-shaped object roughly the angular size of the full Moon. What backyard observers don't see is a swarm of nearly three dozen small satellite galaxies circling the Andromeda galaxy, like bees around a hive.
These satellite galaxies represent a rambunctious galactic "ecosystem" that NASA's Hubble Space Telescope is studying in unprecedented detail. This ambitious Hubble Treasury Program used observations from more than a whopping 1,000 Hubble orbits. Hubble's optical stability, clarity, and efficiency made this ambitious survey possible. This work included building a precise 3D mapping of all the dwarf galaxies buzzing around Andromeda and reconstructing how efficiently they formed new stars over the nearly 14 billion years of the universe's lifetime.

This is a wide-angle view of the distribution of known satellite galaxies orbiting the large Andromeda galaxy (M31), located 2.5 million light-years away. The Hubble Space Telescope was used to study the entire population of 36 mini-galaxies circled in yellow. Andromeda is the bright spindle-shaped object at image center. All the dwarf galaxies seem to be confined to a plane, all orbiting in the same direction. The wide view is from ground-based photography. Hubble's optical stability, clarity, and efficiency made this ambitious survey possible.

In the study published in The Astrophysical Journal, Hubble reveals a markedly different ecosystem from the smaller number of satellite galaxies that circle our Milky Way. This offers forensic clues as to how our Milky Way galaxy and Andromeda have evolved differently over billions of years. Our Milky Way has been relatively placid. But it looks like Andromeda has had a more dynamic history, which was probably affected by a major merger with another big galaxy a few billion years ago. This encounter, and the fact that Andromeda is as much as twice as massive as our Milky Way, could explain its plentiful and diverse dwarf galaxy population.

Surveying the Milky Way's entire satellite system in such a comprehensive way is very challenging because we are embedded inside our galaxy. Nor can it be accomplished for other large galaxies because they are too far away to study the small satellite galaxies in much detail. The nearest galaxy of comparable mass to the Milky Way beyond Andromeda is M81, at nearly 12 million light-years.

Hubble close up snapshots of four dwarf galaxies are on image right. The most prominent dwarf galaxy is M32 (NGC 221), a compact ellipsoidal galaxy that might be the remnant core of a larger galaxy that collided with Andromeda a few billion years ago.

This bird's-eye view of Andromeda's satellite system allows us to decipher what drives the evolution of these small galaxies.

We see that the duration for which the satellites can continue forming new stars really depends on how massive they are and on how close they are to the Andromeda galaxy. It is a clear indication of how small-galaxy growth is disturbed by the influence of a massive galaxy like Andromeda.

Alessandro Savino, lead author
Department of Astronomy
University of California, Berkeley, Berkeley, CA, USA.

Everything scattered in the Andromeda system is very asymmetric and perturbed. It does appear that something significant happened not too long ago. There's always a tendency to use what we understand in our own galaxy to extrapolate more generally to the other galaxies in the universe. There's always been concerns about whether what we are learning in the Milky Way applies more broadly to other galaxies. Or is there more diversity among external galaxies? Do they have similar properties? Our work has shown that low-mass galaxies in other ecosystems have followed different evolutionary paths than what we know from the Milky Way satellite galaxies.

Daniel Weisz, principal investigator
Department of Astronomy
University of California, Berkeley, Berkeley, CA, USA.

For example, half of the Andromeda satellite galaxies all seem to be confined to a plane, all orbiting in the same direction.

That's weird. It was actually a total surprise to find the satellites in that configuration and we still don't fully understand why they appear that way.

Daniel Weisz.

This animation begins with a view of the neighboring Andromeda galaxy. We zoom through a scattering of foreground stars and enter the inky blackness of intergalactic space. We cross 2.5 million light-years to reach the Andromeda system, consisting of 36 dwarf satellite galaxies orbiting the giant spindle-shaped Andromeda galaxy at image center. An ambitious survey by the Hubble Space Telescope was made to plot the galaxy locations in three-dimensional space. In this video we circle around a model of the Andromeda system based on real Hubble observational data.
NASA, ESA, Christian Nieves (STScI), Alessandro Savino (UC Berkeley); Acknowledgment: Joseph DePasquale (STScI), Frank Summers (STScI), Robert Gendler

The brightest companion galaxy to Andromeda is Messier 32 (M32). This is a compact ellipsoidal galaxy that might just be the remnant core of a larger galaxy that collided with Andromeda a few billion years ago. After being gravitationally stripped of gas and some stars, it continued along its orbit. Galaxy M32 contains older stars, but there is evidence it had a flurry of star formation a few billion years ago. In addition to M32, there seems to be a unique population of dwarf galaxies in Andromeda not seen in the Milky Way. They formed most of their stars very early on, but then they didn't stop. They kept forming stars out of a reservoir of gas at a very low rate for a much longer time.

Star formation really continued to much later times, which is not at all what you would expect for these dwarf galaxies. This doesn't appear in computer simulations. No one knows what to make of that so far.

Alessandro Savino.

We do find that there is a lot of diversity that needs to be explained in the Andromeda satellite system. The way things come together matters a lot in understanding this galaxy's history.

Daniel Weisz.
Hubble is providing the first set of imaging where astronomers measure the motions of the dwarf galaxies. In another five years Hubble or NASA's James Webb Space Telescope will be able to get the second set of observations, allowing astronomers to do a dynamical reconstruction for all 36 of the dwarf galaxies, which will help astronomers to rewind the motions of the entire Andromeda ecosystem billions of years into the past.

Abstract
From >1000 orbits of HST imaging, we present deep homogeneous resolved star color–magnitude diagrams that reach the oldest main-sequence turnoff and uniformly measured star formation histories (SFHs) of 36 dwarf galaxies (−6 ≥ MV ≥ −17) associated with the M31 halo, and for 10 additional fields in M31, M33, and the Giant Stellar Stream. From our SFHs, we find: (i) The median stellar age and quenching epoch of M31 satellites correlate with galaxy luminosity and galactocentric distance. Satellite luminosity and present-day distance from M31 predict the satellite quenching epoch to within 1.8 Gyr at all epochs. This tight relationship highlights the fundamental connection between satellite halo mass, environmental history, and star formation duration. (ii) There is no difference between the median SFH of galaxies on and off the great plane of Andromeda satellites. (iii) ~50% of our M31 satellites show prominent ancient star formation (>12 Gyr ago) followed by delayed quenching (8–10 Gyr ago), which is not commonly observed among the MW satellites. (iv) A comparison with TNG50 and FIRE-2 simulated satellite dwarfs around M31-like hosts shows that some of these trends (dependence of SFH on satellite luminosity) are reproduced in the simulations while others (dependence of SFH on galactocentric distance, presence of the delayed-quenching population) are weaker or absent. We provide all photometric catalogs and SFHs as High-Level Science Products on MAST.

Savino, Alessandro; Weisz, Daniel R.; Dolphin, Andrew E.; Durbin, Meredith J.; et al The Hubble Space Telescope Survey of M31 Satellite Galaxies. IV. Survey Overview and Lifetime Star Formation Histories
The Astrophysical Journal 979(2); p 205; DOI: 10.3847/1538-4357/ada24f

Copyright: ©2025 The authors.
Published by IOP Publishing. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)