Andromeda Galaxy Discoveries Pose Challenge to Modern Cosmology

Hello wonderful person, this is Anton, and today we're going to discuss some of the more unusual discoveries and some of the more unusual studies about our neighbor, the Andromeda Galaxy. The galaxy also known as Messier 31, and essentially the largest spiral galaxy next to the Milky Way at a distance of 2.5 million light years. And a galaxy that seems to be on a collision course with the Milky Way, but that collision is still uncertain. But what is certain is that the galaxy seems to be a little bit unusual and doesn't actually seem to fit a lot of models and cannot be easily explained using modern cosmology. As a matter of fact, you could almost say that this galaxy surprisingly violates modern cosmology, at least to some extent. And so in this video, we're going to discuss one of the recent studies that once again confirms this bizarre anomaly, but unfortunately also doesn't actually provide any explanation whatsoever. But first, I wanted to start with one of the most recent studies in regards to its center, because even here we have some new discoveries. And this is in regards to the central galactic region that basically contains the supermassive black hole. And obviously, like so many other galaxies, including the Milky Way, the Andromeda Galaxy also contains a black hole. But compared to the Milky Way, this one here is actually a little bit too massive. In a recent study here, the mass was confirmed to be approximately 100 million solar masses, or about 22 times more massive than the one in the Milky Way. And here, even though the galaxy is just a little bit bigger than the Milky Way, for some reason it seems to contain a much more massive central black hole. This might actually become important in a few minutes. But it also is surprisingly quiet. It's only showed occasional signs of activity, and for the most part, seems to be surrounded by a relatively dense cluster of stars, making this a highly populated region. As a matter of fact, one of the strange features in this galaxy is the fact that it seems to contain two central regions, or basically two large concentrations, separated by about five light years, in this image designated as P1 and P2. With both regions containing a lot of really bright A-type stars, and huge amounts of dust. But exactly why there is a double nucleus has always been a bit of a mystery. Now one explanation suggests that maybe one of these regions is just a bunch of stars orbiting around a central black hole, with a lot of these stars potentially having a very high eccentricity, so they move really far away from the black hole, but how this would form is of course unknown. Obviously, a galactic collision or a black hole collision could have created something like this, but there's really no evidence for anything yet. Alternatively, maybe the second nucleus is some kind of a remnant of an ancient galaxy that was basically observed by the Andromeda a very long time ago. But this is now believed to be maybe not a good explanation, simply because such a nucleus should not exist for so long, and would have already broken apart a long time ago. Either way, this has always been a bit of a mystery. But because this galaxy is so close to us, to astronomers this is a perfect opportunity to study how galaxies evolve alongside central black holes. And that's because here we can actually see the galactic core pretty well. And so not so long ago, scientists were able to combine observations from the X-ray observatories, such as the famous Chandra telescope, with detections of neutrinos by facilities like the IceCube neutrino detector in Antarctica, with these new discoveries basically linking neutrino production with X-ray flares. We're essentially confirming that whenever we see more neutrinos coming from this region, it seems to be connected to the supermassive black hole, because we also see X-ray flares. And even though X-rays were coming from several regions, with the region you see right here known as SSS producing a lot of X-rays, surprisingly it's the region known as P2 that was producing most of the neutrinos, which has already been suggested as the main region where the black hole seems to reside. And so here once again, P2 was confirmed to be the home of the central black hole, as suggested by previous studies. But more importantly, scientists have also confirmed that for some reason, since 2006, this black hole has actually been in a kind of a state of elevated activity. Or basically since 2006, it was actually producing quite a lot of flares, for reasons that are still unknown. There was a major eruption in 2006, there was another one in 2013, and more are expected soon because even now, there seems to be an elevated X-ray flux. Or basically the black hole seems to be producing more X-rays than it should. And so there are definitely quite a lot of mysteries right here in the center. But a much bigger mystery that was also described in one of the recent studies, was just discovered coming from the outskirts, or from various dwarf galaxies around the Andromeda. And while technically the Andromeda galaxy's dwarf satellites have always been a bit mysterious, mostly because of their orbit. For example, back in 2006, one of the major discoveries about this galaxy was that, for some reason, quite a lot of companion galaxies here were actually orbiting in a kind of a single plane. And here's one of the images produced back in 2006. Basically here, several galaxies orbit in a kind of a polar plane. And it was not entirely clear why or how to explain this. We obviously expect planets to orbit in a single plane around a developing star, but this is not expected of a galaxy. Based on various galactic simulations such as Illustrious Project, and specifically TNG-50, we actually expect a lot of these dwarf galaxies to kind of orbit all over the place. This is referred to as near isotropic, which is kind of expected of all galaxies. And it's sort of observed around the Milky Way as well. Yet here, the Andromeda didn't seem to possess this, at least for some of these galaxies. But in this recent study, the mystery kind of intensified. The study by Kosuki, Jamie, Kanahisa, and the team you see right here, sort of confirmed that, surprisingly confirmed that many satellites around Andromeda seem to have a bizarre asymmetry. And asymmetry that's super difficult to explain. Here of all 37 known dwarf galaxies, 36 seem to be positioned in a way that makes no sense. They're essentially contained in a kind of a cone of 107 degrees toward the Milky Way galaxy. Or just to help you visualize, it kind of looks like this. Notice how a lot of these galaxies seem to be in a single location, with many of them also orbiting in this somewhat strange plane. And this asymmetrical distribution right now really makes no sense. Because a lot of them seem to be aligned toward the Milky Way galaxy, and no cosmological model can explain exactly what's happening. As I mentioned, this seems to actually challenge the standard model of cosmology, at least to some extent. Because in that model, these satellites are predicted to be all over the place, forming a kind of a near isotropic distribution. Yet 36 out of 37 seem to be in this very strange cone. And while at first, obviously, this was assumed to be maybe some kind of a observational bias or lack of data. Or basically, maybe we're just not seeing many other galaxies far away from the Milky Way, just because closer galaxies are much easier to see. But despite improvements in our telescopes, and despite even better observations, this still seems to persist. This is despite the fact that we've discovered new satellites, and despite the fact that some of the brighter satellites are actually on the far side in this video. And so even though there might be some observational bias, it does not seem to answer everything. Alternative explanations suggest that this could be the result of a tidal interaction, or even a collisional interaction, between the Milky Way and the Andromeda. And that's because both galaxies, as I mentioned before, are expected to collide in the next 5 billion years. But calculations in the study suggest that tidal effects cannot actually produce anything like this at all. Just because the galaxies are still far away from each other, at 2.5 million light years, and the tidal effects in this case would be absolutely minimal. Here's actually one of the maps showing us the distribution of galaxies, and the distance between the Milky Way and the Andromeda. And even here, it becomes pretty obvious that many of these dwarf galaxies seem to be misaligned toward the Milky Way. As a matter of fact, when modelling this, when the researchers tried to recreate this by chance, it only happened 0.3% of the time. Which once again suggests that this is extremely unlikely to happen in a standard cosmological model. I mean, it's possible, just super unlikely. 99.7% unlikely. And because here the explanation is most likely physical in origin, or basically this is not the result of a bias, and these galaxies are indeed seem to be kind of lopsided, this is probably the result of some kind of a bizarre formation history for the Andromeda galaxy. But exactly what happened, and what influenced this, is of course unknown. As a matter of fact, even though the signs here point at the Milky Way's influence, we have no idea what influence this would be. If this was indeed the result of the Milky Way, there is really no explanation at all. Although there was one potential explanation that researchers do tackle in a study. Here, maybe this was all the result of some kind of a single accretion event where a lot of satellites, from some kind of a large association, all came into the galaxy at once. Or essentially this was a chunk or a cluster of satellites arriving into the Andromeda system within just a few million years. But according to researchers behind this study, this also doesn't make sense because here, such a symmetry would only exist for approximately 500 million years maximum, and many of these galaxies seem to contain very different orbits, and even very different orbital energies. Basically suggesting that they're moving at different speeds, in different directions. So there's actually not a lot of connection between them individually. With the last explanation being that, maybe, we're just seeing this galaxy at this one specific moment, when all of the satellites are for some reason in a single location. It's kind of like when we have the planetary alignment in the solar system, with all of the planets on a single site. But since this is 36 galaxies, whose orbits take hundreds of millions of years on average, such an alignment would also be super super unlikely. Not impossible, just extremely rare. Which basically leaves us with Andromeda being this unusual outlier, that seems to defy cosmological theories and raises a lot of questions about Andromeda's evolutionary history, and how this galaxy and its satellites formed. And especially because of that mystery of double nucleus I mentioned previously, which might actually connect all of this somehow, but we don't really have the exact explanation yet. Basically, here it seems to be the result of some kind of a massive collision a long time ago, which potentially formed this somewhat strange distribution. And because in this case, there are actually two mysteries when it comes to orbits of these satellites, the first mystery being the asymmetry, and the second mystery being several galaxies orbiting in a single plane, here this raises several questions on whether Andromeda is just an anomaly, or if our understanding of galactic formation is maybe incorrect. And so yeah, one of the biggest mysteries in cosmology is technically right here at our doorsteps. But luckily for us, we have telescopes like the Euclid that has just begun its operation, that will most likely discover even more mysteries around Andromeda, and will probably provide us with some answers as it discovers more of these invisible galaxies, and as the number of satellite galaxies around the Andromeda grows in the future. Once we're able to see hundreds of satellites, we'll probably be able to tell what actually happened here. But with just 37, it is maybe a bit of a bias. And so until future discoveries, or until we discover something else, that's all I wanted to mention. Check out some of the previous videos about Andromeda in the description, thank you for watching, subscribe, share this with someone who loves robots based in sciences, come back tomorrow to learn something else, support this channel on Patreon by joining the channel membership, or by buying the wonderful person t-shirt you can find in the description. Stay wonderful, I'll see you tomorrow, and as always, bye bye.