Colliding and Interacting Galaxies

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Galaxies are not small compared to the distances between them. Therefore, they crash together over hundreds of millions of years, creating new stars and disrupting their shapes. This is part of my complete intro Astronomy class that I taught at Willam Paterson University and CUNY Hunter.
This remaster tried to get rid of the background music so there’s some artifacts.
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@Dragrath1 Ай бұрын

Oh hello seems KZbin has brought you back into my feed. I think you meant Andromeda is approaching us not the Milky Way galaxy lol. In the context of galaxy collisions and their timescale the first encounter with what is today the Sagittarius dwarf spheroidal galaxy was 5.8 billion years ago but the remnant core still persists today with its tidal streams wrapped around our galaxy as it has gone through our galaxy several times. Also from the combination of GAIA astrometry with galactic spectroscopic surveys it is pretty clear that despite the mismatched size the collision of the Sagittarius dwarf spheroidal it had a fairly profound effect on stirring up star formation with the collision inducing the largest single starburst episode within the Milky Way's history accounting for the galaxy forming somewhere around half of the total stars the Milky Way has ever formed within a roughly billion year window. An interval which just so happens to overlap with the formation of our solar system which began 4.7 billion years ago. I suspect it is not a coincidence that the Sun formed at the tail end of the Milky Way's single largest star formation episode. Anyway as for the simulations on the Milky Way and Andromeda I think I remember that model it was from a bit over a decade ago and had those pretty illustrations. Unfortunately that simulation there is a bit out of date as thanks to the expanded surveys and high precision astrometry provided by GAIA an avalanche of new data show things are way more complicated and interesting. The main consequence is these models have pushed the timing of the collision back several billion years as evidence indicated that Andromeda will miss the Milky way on its first pass over shooting our galaxy. This change is largely a consequence of the discovery that the Large Magellanic Could is much more massive than indicated by its stellar luminous mass with a total gravitational mass range closer of more than a tenth and less than a third the total mass of the Milky Way with the most likely range being somewhere around a quarter of the Milky Way's total mass with the galaxy and its dozen or so satellite galaxies being on their first pass of the Milky Way. Because of this higher mass the LMC and its retinue of galaxies (i.e. galaxies which share its proper motion relative to the Milky Way) the LMC is having a number of discernable effects on the Milky Way galaxy already the first effect of this proximity being the bending/diversion of the Milky Way's stellar streams within its galactic halo. This is not the only impact as the LMC offsets the barycenter of the LMC Milky Way system outside of the galactic center inducing what appears to be a sloshing effect on our galaxy and might possibly even be related to the discovered warping within our galaxies disk. Furthermore it also finally gives us a reasonable explanation for the Magellanic streams as with the new higher total mass value the LMC has enough gravity to support its own significant gas halo which encompasses the LMC and its closest satellite the SMC which becomes deformed in a shock front as the Magellanic system rams through the Milky Way's own larger gas halo. Because of this mass the LMC system is on a one way trip towards a head on collision as its momentum is broken by the galaxy halo interactions and the high gravitational attraction ensures the LMC will be unable to leave resulting in the Large Magellanic Cloud colliding directly between 1 and 2 billion years from now likely initiating a large starburst episode. The discoveries involved with regards to the revelations of the LMC are quite fascinating and sadly have not gotten nearly enough attention given the large implications they have for the future evolution of the Local group as the first encounter with Andromeda will not happen until around 5 billion years time due to Andromeda overshooting the Milky Way. There is also some cool history form the Milky Way and Andromeda which we are starting to piece together for example Andromeda "just" went through a major starburst episode 2 billion years ago much like the Milky Way did with the collision of the Sagittarius dwarf spheroidal galaxy. The milky way has had a number of collisions but there seems to have been a fairly long lull after the GAIA Enceladus finished somewhere around 9 billion years ago. At least there doesn't seem to have been any major collisions during that time. This is the golden age of galactic archeology so many new discoveries of our ever dynamic disequilibrium galaxy.