Our galactic neighbor Andromeda has a number of satellite galaxies – and they show strangely on us

If you buy links to our articles, the future and its syndicate partners can earn a commission.

Our neighboring Andromeda galaxy (Messier 31 or M31) seems to have a one -sided arrangement of satellite galaxies that defy scientific models, and blunt astronomers who also try to find out why so many of the family members of this galaxy show in our direction. All up to one of the brightest 37 satellites of M31 are on the side of the Andromeda spiral, which faces our milky galaxy -the strange out -out spiral 110, which is easily visible in amateur pictures of the Andromeda galaxy.

“M31 is the only system that we know that we show such an extreme measure of asymmetry,” Kosuke Jamie Kanehisa from the Institute of Physics and Astronomy at the University of Potsdam in Germany told Space.com.

Accordingly cosmologyStandard model that universe Is filled with huge clouds dark matter. Large within these clouds Galaxies Like Andromeda and ours Milky Way grow – and they grow over merger With countless smaller dwarf galaxies that were drawn from which Gravity the dark matter. The dwarf galaxies that we see today in large galaxies are the remains of this formation process. According to this picture of “hierarchical growth”, these dwarf satellite galaxies should randomly be distributed around larger galaxies. However, this does not quite find what astronomers find.

A large part of the M31 dwarf satellites are limited to an airplane around Andromeda galaxy. As confirmed In early 2025 from the Hubble world space telescopeAnd a similar satellite aircraft exists around the Milky Way. There are also preliminary evidence of a level of satellites around another nearby galaxy, Centaurus A. For galaxies that are still nearby, it is difficult to find weak dwarf galaxies and measure the distance to them so that astronomers cannot safely say what these systems do. But even the levels of satellite scientists are difficult to explain in the standard model of cosmology.

And now M31 and its satellites have become even more mysterious, and almost all satellites are located on the M31 website, which are geared towards the Milky Way.

New simulations of Kanehisa and his Potsdam colleagues Marcel Pawlowski and Noam Libeskind show that, according to the standard model of cosmology, the likelihood that such a ordered arrangement is less than 0.3%. And yet the closest galaxy beats this chances for us. When is a coincidence just a coincidence and when does it open a window in a deeper secret?

The dwarf galaxies circle M31 at different speeds and distances; They will be more common in another billion years. At first glance, the current orientation could only be seen as a chance. However, the low probability that this coincidence will occur means that it is the kind of chance to believe in the scientists.

If something appears in a certain way in the cosmos, it is usually because something has meant that it is. Nevertheless, there is no fixed evidence that has so far indicated a certain explanation, except that this orientation is now present. Its cause must be new.

“The following is speculation, but I expect that the underlying guilty -based culprit behind the discrepancy of the M31 system with cosmological expectations is a unique history of accretion,” said Kanehisa. “The fact that we see the satellites of M31 in today’s unstable configuration- which is at least strange- could point out that many have recently been viewed about two to three billion years ago in relation to the great merger in terms of Andromeda.”

This great merger included a medium-sized galaxy that was consumed by the larger Andromeda galaxy. The youngest of the Hubble Space Telescope deep in Andromeda Was able to pursue the disorder in M31 that the merger left in its entourage: stars that were eaten by the galaxy eaten by M31 and creates a star formation. Even if the dwarf galaxies are the latest arrivals that remain behind this galaxy merger, it still doesn’t quite explain why they are all on the M31 website and are opposite our Milky Way.

Another thought is, could the dwarf galaxies literally point to the perpetrator on our M31 side? Not so fast. If our Milky Way played a role, we could expect our dwarf satellites to show their own Einsieden M31 – but they don’t and the gravitational times between the two galaxies are not strong enough to draw M31S dwarfs into this arrangement.

There are also some restrictions that are referred to about the unlikely shooting of M31 satellites.

Exact data regarding the movement of dwarf galaxies are only known for four of the satellites of the M31 (five when IC 10 is counted, which is a controversial member of the M31 system), which means that simulations can be a bit rough. However, astronomers aim to determine the applications for at least a dozen M31 dwarfs within one further or two year with the publication of the next data record. Gaia Astrometric mission.

“As soon as we have a more extensive sample of M31 dwarfs with suitable movements, we should be better positioned in order to examine the time development of the observed asymmetry,” said Kanehisa. In other words, we could better understand how long this one -sided orientation can stay in place.

Another restriction is that there are probably many weaker, still undiscovered satellite dwarf galaxies around M31. We know that this is probably the case, since the standard model of cosmology predicts that there should be more dwarf satellites in both M31 and in our Milky Way than we have currently found. These undiscovered dwarfs would be small and contain only a few stars, which makes it difficult to identify. In fact, the weakest dwarf galaxy, which is currently known for M31, named Andromeda XXXVwas found on the other side of M31 and does not fall into the one -sided pattern of the others.

“We have to wait and see whether the global asymmetry with the detection of weaker dwarfs will be created. If we find that only lighter dwarfs have participated in the asymmetry, this would also raise further questions about their origin,” said Kanehisa.

Related stories:

– How did Andromeda’s dwarf galaxies form? The Hubble telescope finds more questions than answers

-The Hubble world space telescope reveals the richest view of the Andromeda galaxy (picture)

– Tental stars could ruin our view of thousands of exoplanets, Hubble telescopes

The last restriction is that the alignment of the M31 system may not be as unlikely as we think. Only very few galaxies beyond our local group have interpreted their dwarf families in detail – the galaxies are simply too far away and too weak, and those we can see have no precise distance measurements, so we cannot safely say which side of your parents galaxy you are on.

“We cannot yet be sure that similar extreme systems do not exist out there or that such systems are negligible,” said Kanehisa.

The dwarf family of Andromeda Galaxy is a mystery. At first it was the unusual flat aircraft around which more than half of them creep up, and now this shootout. It only shows that sometimes it is our closest neighbors who turn out to us as on strangers.

The results were published on April 11th in the magazine Natural astronomy.