Our adjacent Andromeda galaxy (Messier 31, or M31) appears to flaunt a biased arrangement of satellite galaxies that defies scientific models. All but one of the M31’s brightest 37 satellites lie on the side of the Andromeda Spiral facing the Milky Way galaxy. The strange thing is the syier 110, which is easily visible in amateur images of the Andromeda galaxy.
“The M31 is the only system that we know to show such an extreme degree of asymmetry,” Kosuke Jamie Kanehisa of Institutfür Physikund Astronomie, at the University of Pottsdam in Germany, told Space.com.
According to CosmologyStandard model of universe Filled with vast clouds of Dark matter. Among these clouds, it’s big Galaxy Andromeda, us, etc. milky way Grow – and they grow by merge In countless small wharf galaxies drawn into gravity of dark matter. The d-star galaxies found around today’s large galaxies are leftovers from this formation process. According to this photo of “hierarchical growth,” these d-star satellite galaxies should randomly spread around larger galaxies. But that’s not something astronomers find.
Most of the M31’s dwarf satellites are limited to planes around the Andromeda Galaxy. As confirmed Early 2025 Hubble Space Telescopeand similar satellite surfaces exist around the Milky Way. There is also provisional evidence of the satellite plane around the nearby galaxy, Centaur A. For galaxies far away in galaxies, it is difficult to find and measure the distance of a faint d star. But even the plane of satellite scientists confirms that it is difficult to explain in standard models of cosmology.
And now the M31 and its satellites are even more mysterious, with almost all satellites located on the side of the M31 facing the Milky Way.
A new simulation by Kanehisa, along with his Potsdam colleagues Marcel Pawlowski and Noam Libeskind, shows that the likelihood of having such a biased arrangement is less than 0.3%, according to the standard model of cosmology. Still, the galaxy closest to us is to beat those odds. So when is a coincidence a coincidence a coincidence, and when does it open a window into a deeper mystery?
All the galaxies of star d orbit the M31 at various speeds and distances. In another billion years, they will expand. So, in the face of this, the current alignment can be considered by chance. However, the unlikely chance of this coincidence occurring means that it is a kind of coincidence that scientists struggle to believe.
If something in the universe appears in a certain way, it is usually because something has done it that way. Still, there is no solid evidence so far pointing to any particular explanation, except that this alignment is present. The cause must be recent.
“The following is speculation, but I expect the underlying culprits behind the contradictions of the M31 system with cosmological expectations will be a history of some unique accumulation,” Kanehisa said. “The fact that we can see the M31 satellite in this unstable configuration today — the strange thing to say the least, may point to the recent fall of many who may be linked to the major mergers Andromeda appears to have experienced between 200 million and 3 billion years ago.”
This major merger included medium-sized galaxies consumed by the larger Andromeda galaxies. Hubble Space Telescope Recent Dive deeper into Andromeda I was able to track the M31 failure. The merger remains in its wake. Cannibalism from the galaxy that M31 ate, and cannibalism from the galaxy that produces a burst of star formation. However, even if the dwarf galaxy, which has been late in the merger of that galaxy, has yet to fully explain why it is on the side of the M31 facing our Milky Way galaxy.
Another idea is that the d-star galaxy on our side of the M31 literally refers to the perpetrator? It’s not that fast. If our Milky Way played a role, we might expect our d-star satellite system to show its own system biased towards the M31, but they are not, and the gravitational tidal force between the two galaxies is not strong enough to draw the d-star of M31 into this arrangement.
There are also some caveats to note about the eccentricity that the M31 satellite may exhibit.
Accurate data on the movement of dwarf galaxies is known for only four of the M31 satellites (5 if IC 10 is counted, a contested member of the M31 system). This means that the simulation can be a little rough. However, astronomers aim to determine at least one M31 dwarf movement to high accuracy within one or two. Gaia Space measurement mission.
“If we have a more substantial sample of M31 dwarves with appropriate movement, we should be better positioned to study the temporal evolution of observed asymmetry,” Kanehisa said. In other words, you can better understand how long this biased alignment can remain.
Another warning is that there are likely many fanters remaining that have yet to be discovered on the satellite star’s dwarf galaxies around M31. We know that this is probably the case, as Cosmology’s standard model predicts that there should be more d-satellites in both the M31 and our Milky Way than we currently discover. These undiscovered dwarfs are small and have fewer stars, making them difficult to identify. Indeed, the most faint d-star galaxy currently known around the M31 is named andromeda xxxvfound across the M31 and does not fall into other people’s biased patterns.
“We need to wait and see if global asymmetry persists in detection of boring dwarfs, but if we find that only brighter dwarfs are involved in asymmetry, this will raise more questions about their origins,” Kanehisa said.
The final warning is that the alignment of the M31’s system is probably not as unlikely as we think. Galaxies other than our local groups map dwarf families in detail. Galaxies are too far and too faint, and those that can be detected do not have accurate distance measurements, so it is impossible to say for certain which side of the parent galaxy is on.
“We cannot yet be certain that similar extreme systems do not exist there or that such systems are negligible rare,” Kanehisa said.
The little family of Andromeda Galaxy is a mystery. First, it’s an unusual flat plane, with over half of them on track, and now this biased thing. It only shows that what turns out to be the most alien to us is sometimes our closest neighbor.
The survey results were published in the journal on April 11th. Natural Astronomy.
