Talk:Andromeda–Milky Way collision/Archive 1

Comment on deletion proposal
Where is the information on this speculative theory going to be put? On the Andromeda galaxy page? In general I don't like information to be lost unless it's provably fringe science, but if this theory is moved to the Andromeda Galaxy, and maybe shortened, then everything will be fine with me. Rursus declamavi;  22:40, 13 February 2007 (UTC)

This sort of thing would fit into a discussion of the dynamics of the Local Group, though Local Group has nothing mentioning dynamics in it presently. Sagittarius_Dwarf_Elliptical_Galaxy necessarily talks about galactic collisions involving the Milky Way, and there is some mention of the process in galaxy formation. My preference would be to have this get included in an article about dynamics of the Local Group; it's probably too large to fit within the Local Group article itself. BSVulturis 16:03, 15 February 2007 (UTC)


 * Hmm. The article was to be kept anyway, which is a good thing. Otherwise, where would the information have been put? In Andromeda (too big already), in Milky Way (too big already), in Local Group maybe. But now it gets an article for future improvements. I'll take a look for missing (?) links from the mentioned places, to assure the article gets its readers. Rursus declamavi;  18:20, 18 February 2007 (UTC)

some notes
The opening sentence attributes this theory to the toronto and harvard astronomers, however I have not seen anywhere where they claim that they originated the theory. The work takes it for granted that a collision will occur and then they simulate the outcome. The earliest reference to the radial velocity dates to Slipher in 1912 and I suspect that other astronomers have proposed this theory before.

This article seems to imply that the work of Dubinski is a definite prediction of what will happen, however he clearly states that it is speculation.

"The Milky Way and the Andromeda galaxy will likely fall together and merge within a few billion years. In this speculative simulation, the two galaxies..." and "I have set up a model system of colliding galaxies that reflects the current state of our the Milky Way and Andromeda system. There are still some uncertainties about the exact trajectories and masses of the two galaxies but I have set up a plausible case where they fall together and collide..." 

--mikeu 15:06, 17 February 2007 (UTC)

Should there be a mention that such a collision repudiates the Big Bang Theory which postulates that all galaxies are moving away from each other due to the expansion of space? If all the matter of the Universe was created at a singularity which expanded then everything must be moving away from everything else. As its clearly not, the Big Bang Theory has a serious problem. —Preceding unsigned comment added by 94.116.162.109 (talk) 10:19, 4 March 2011 (UTC)

Are there any peer reviewed references to this subject?
I am a scientist that would like to learn more about this proposed theory. Does anyone know if there any peer-reviewed references to this topic? Lunokhod 00:11, 19 February 2007 (UTC)


 * I have been looking, and have not been able to find one.--mikeu 02:28, 19 February 2007 (UTC)

Here's a just-published paper that covers the topic to a nice level of detail: http://arxiv.org/abs/0705.1170v1 (T.J. Cox & Abraham Loeb, The Collision Between The Milky Way And Andromeda, Harvard-Smithsonian Center for Astrophysics) &mdash; RJH (talk) 16:09, 11 May 2007 (UTC)

The more recent being: http://adsabs.harvard.edu/abs/2012ApJ...753....9V — Preceding unsigned comment added by 212.186.52.60 (talk) 13:19, 5 September 2012 (UTC)

Future event?
While it's pretty sure that the collision, if it occurs, will occur in the future, 4.5 billion years is a long time. The depth of our knowledge concerning the Andromeda-Milky Way collision is not likely to increase very much within the lifetime of the human race, let alone Wikipedia. Therefore, I removed the template saying it was a future event. If I erred, please tell me. DrExtreme 20:36, 3 March 2007 (UTC)


 * The event may not happen at all. Hornberry 15:08, 5 March 2007 (UTC)


 * It is kinda funny to have a future tag, though, so I'd put it back just for whimsy... Wl219 06:13, 26 March 2007 (UTC)


 * Hmm, I think it would be amusing to label it a future event, too. It's not technically incorrect, either, as even DrExtreme admitted. -Mysterius 22:26, 9 August 2007 (UTC)


 * I thought we still weren't sure whether it was going to happen? Something about not having an accurate enough measure of Andromeda's lateral velocity? That at least is something our knowledge about may increase. (Also, what exactly is your projected lifespan for the human race? What limits it?) --DocumentN 04:29, 17 September 2007 (UTC)

Viewing
I think the sentence "If the theory is correct, the stars and gas contained in Andromeda will be visible to a naked-eye viewer (if one exists on Earth at the time) in approximately three billion years." is kind of funny, considering that Earth will by that time will have long been incincerated by our dying sun. Just thought I'd point that out, Masterof148 Correct me if I'm wrong, but I believe the image caption "as it might be seen from Earth" subtracts credibility from the article. 86.92.226.147 (talk) 23:38, 29 May 2008 (UTC)
 * It'll actually be about 5 billion years before the sun leaves the main sequence. See sun for more information. WilyD 23:31, 16 April 2007 (UTC)
 * According to the sun article, in only 1 billion years the earth's surface will be too hot to sustain liquid water24.58.175.197 (talk) 17:21, 31 October 2008 (UTC)john wilkinson

Citation not needed for math
I deleted the {fact} tag on this sentence:
 * ... the nearest star to the Sun is in fact almost thirty million solar diameters away from the Earth

This is a simple calculation based on pulling the relevant numbers from those two articles. —johndburger 13:37, 18 May 2007 (UTC)

Merge with Milkomeda
There is no need for a separate article to discuss the proposed name for the new galaxy—Wikipedia is not a dictionary. —johndburger 23:27, 24 March 2008 (UTC)


 * I wouldn't even bother with the merge. It was a joke, not an unofficial nickname.  Loeb jokingly calls this future galaxy "Milkomeda," but others have also referred to it as "Milkymeda" or the "Andromeda Way."   --mikeu (talk) 00:49, 25 March 2008 (UTC)
 * Indeed, at best you could include an offhand comment that he called it as such here. Wily D 13:50, 25 March 2008 (UTC)
 * Agree with the above comments - at most the name deserves a brief mention in this article. Milkomeda should be redirected here in case someone does look it up. Cosmo0 (talk) 12:21, 27 March 2008 (UTC)

Yah, that's about all I was thinking was merge-worthy—I did the deed, including the redirect, and cleaning up the only link to the other article. —johndburger 01:38, 28 March 2008 (UTC)

LOL
So, Wikipedia has an article about a certain but future event. The likelyhood of Wikipedia's existence at that time, or at a relevant time, is subjective, but still...

Just think about let's say about The Library from Alexandria... —Preceding unsigned comment added by 89.137.70.184 (talk) 20:16, 5 April 2008 (UTC)


 * I personally think it's likely that Wikipedia, or some daughter/granddaughter/(great great...) great grandaughter project of Wikipedia will exist at this time. No matter what beings exist in that future time, they will find the wiki concept useful. --86.135.222.11 (talk) 15:29, 13 September 2008 (UTC)
 * In billions of years? I seriously doubt the written word will survive the next thousand years. —Preceding unsigned comment added by 84.70.139.69 (talk) 13:54, 14 September 2009 (UTC)

Hm... I'm skeptical. --76.71.238.169 (talk) 00:54, 20 September 2008 (UTC)

ejection
What happens if the sun isn't ejected? It seems there is very little risk from star collisions, but what about the lose gas in the two galaxies? Isn't that supposed to make a mess?


 * That gas has a density of something like 1 - 10 atoms per cubic centimeter. What is a bit of an issue is that Sagittarius A* or Andromeda's Black Hole will turn into a quasar, which could be unhappy.  Does Wet merger have an article? Wily D  02:45, 1 September 2008 (UTC)

It may not matter what would happen to the sun in the collision -- if such occurs. According to the article on the Sun, due to the Solar evolution along its sequence (10% increase/billion years in sun's luminosity), in ONE billion years the earth's surface temperature will be too hot to sustain liquid water. So, we don't have 5 billion years (the lifetime of the Sun as the main sequence star); we don't even have 2-3 billion years (the projected speculative collision with the Andromeda). We only have less than one billion years! (Unless there are other unknown life-ending events even before then). So, we've already gone through the most of the earth's life-existence history. How old age creeps up on you...Of course, if we moved to another planet, or changed the earth's orbit -- likely achievable levels of technology if nothing intercedes in the meantime, then we could be around to mind what happens to the sun in the collision.24.58.175.197 (talk) 18:15, 31 October 2008 (UTC)john wilkinson

Date for event Incorrect
I wanted to point out that the pre1vious statement on Wikipedia which stated that this collision was due to take 1place in 7 billion years time is incorrect. This is not logical because the two galaxies, Milky Way and Andromeda are only two billion light years away from each other and are traveling at about 250,000 miles per second closer to each other. Also the Sun will be departing its main sequence lifetime and starting up the asymptomatic giant branch as it will be quickly running out of hydrogen fuel. If this event actually were due to take place in 7 billion years Mercury and Venus would have long been engulfed by our deceased Sun which at this point would be a white dwarf. On a final note some websites and scientists are only predicting two or three billion years time which the Sun would be beginning to exit out of its main sequence but would still be a stable star. I don't want to see any more changes about such dramatically long time scales regarding this event.

...... the hell are you on??? Traveling fast than the speed of light towards each other! No. O_o —Preceding unsigned comment added by 41.145.33.209 (talk) 23:32, 24 February 2010 (UTC)

Changing some of the wording
I am going to change some of the wording to reflect the fact that this event is not a 100% certainty and make Earth a wikilink andyzweb (talk) 21:04, 16 October 2009 (UTC)

Change in time estimation
Changed "3-5 billion" to "3 to 5 billion" in the main section at the top of the article to improve readability.

93.96.103.199 (talk) 19:45, 6 January 2011 (UTC)


 * The intro has now been changed to read simply "4 billion". What is the uncertainty in this figure?  Is it ±1 billion as the previous comment suggests, or is it more?  Also, is this supposed to be when the halos first touch, or when they reach their closest center-to-center distance?  Does anyone know?  --Lasunncty (talk) 08:12, 6 August 2013 (UTC)

Dark matter halos are hypothetical, yet discussed as fact
Seems to me the following line should be rewritten to reflect the hypothetical nature of dark matter and dark matter halos. "This suggests that the dark matter halos, although possibly not the actual disks, of the galaxies will collide." — Preceding unsigned comment added by 204.86.71.226 (talk) 20:06, 13 March 2012 (UTC)

Increase in cosmic rays & supernovae?
One might speculate that the interaction may lead to a significant increase in cosmic ray generation, plus a higher risk of nearby supernova events from the formation of starburst regions. I wonder if there is anything about this in the literature? Regards, RJH (talk) 18:01, 11 May 2012 (UTC)

Today's News
They will collide. 94.30.84.71 (talk) 19:50, 1 June 2012 (UTC)

Random stuff trying to debunk Big Bang theory
I found some random stuff on this article that appears to be from someone trying to pick a bone with the Big Bang Theory. For example, I just removed "There is also the possibility that the whole Big Bang thoery is bunk because it proposes all matter moving away from a central point." from the section on "Possible Quasars," also "Such collisions of stellar systems suggest that the Big Bang theory is deficient, that a wide spread evolution of the universe is in fact true." from the section on "Certainty." They had a number of signs of vandalism, and they had no real relevance to the article. I just thought I'd mention this here so people could be on the lookout for re-occurrences of this kind of thing. 76.191.17.73 (talk) 03:12, 15 June 2012 (UTC)


 * Thanks for taking care of that. The additions in question were made by . They appear to be little more than unsourced ramblings or borderline vandalism. Will keep an eye on the page and the user. -- Racer X11 Talk to me Stalk me  03:51, 15 June 2012 (UTC)

An apparent conflict in the section on black holes
The section on the SMBH says: "These black holes will converge near the center of the newly formed galaxy, ... Gas taken up by the combined black hole could create a luminous quasar .." but later says "The quasar, if it were to be created at the center of the Andromeda Galaxy, would be visible from Earth, ... However, if a quasar were to be created at the center of the Milky Way, it would not be visible due to the dust between Earth and the galactic center." There are two problems with the latter steatement, first it implies the quasar would form in one or other of the galaxies before they merge significantly and secondly the dust and gas clouds which lie between us and Sag A* at present are unlikely to remain on the line of sight as the merger distorts the structures. 192.93.164.28 (talk) 12:21, 19 September 2013 (UTC)


 * I also found that material contradictory/incoherent, so i removed it. My guess (linked sources were broken) is that these were speculations unrelated to Milkomeda re the visibility of quasars if they were centered in each pre-merged galaxy."alyosha" (talk) 18:03, 14 March 2014 (UTC)

What is the little galaxy around Andromeda and Milky Way Galaxies in the simulation video?
When Andromeda anbd Milky way collided in the simulation there was a small galaxy that seem to orbit the "Milkomeda", what galaxy is that? — Preceding unsigned comment added by CDH31211811 (talk • contribs) 23:08, 23 February 2014 (UTC)


 * You are speculating on something that does not exist in reality. David J Johnson (talk) 23:13, 23 February 2014 (UTC)


 * There is a 3rd, smaller galaxy at the beginning and throughout the simulation. Since the simulation is of the future of the the actual merger, i think it's a fair question about reality. Looking at the summary of https://en.wikipedia.org/wiki/File:Andromeda_and_Milky_Way_collision.ogg, though my French is terrible, it seems to indicate the galaxy in question is the Triangulum Galaxy. Let me know if i'm wrong. "alyosha" (talk) 18:14, 14 March 2014 (UTC)
 * No, you are correct. The galaxy in question is the Triangulum Galaxy, which happens to be the 3rd largest and brightest galaxy in the Local Group.

Typo in mobile short description
After enabling Beta and going to this article while in mobile view, the article's short description (under title) reads "Excpected further Andromeda Galaxy–Milky Way Galaxy collision". "Excpected" should be "Expected". Note: This seems impossible to fix using the editor. acc12345acc. (talk) 19:02, 9 October 2016 (UTC)

Black hole consumption of stars possibly about every ten years?
According to a Jiji Press article at http://jen.Jiji.com/jc/eng_afp?k=20170228035359a new research published in the journal Nature Astronomy suggests stars might be consumed by the central black holes at a much higher rate than previously thought - perhaps about every ten years. Sorry, I haven't read the original Nature Astronomy research article nor otherwise investigated further. I don't feel qualified to edit this Wikipedia article, so my comment here is just for reference.

(I alerted Jiji Press about an error in their original article - about 4.5 million rather than billion years was stated in that article.) --H Bruce Campbell (talk) 12:31, 2 March 2017 (UTC)

Speed of movement towards does not match with other sites on Wikipedia
Example: The article about "Future of an expanding universe" does state another speed of movement of the 2 galaxies coming closer. Please check that. E.g. if you take the time 4*10^9 years and the distance 2,5*10^6 light years as given, then you can compute the velocity. Would of course be very dubious if you computed this way. In(approximately)4.696 billion years, our galaxy will collide into another galaxy called Andromeda. — Preceding unsigned comment added by 2600:8800:1300:25b:e86e:add0:b8d1:3062 (talk • contribs)
 * I reverted 4.696 because your calculation is Original research. The first two references say 4 billion, the third says 5 billion and the fourth is offline. It may seem like a simple time=distance/speed problem, but you yourself said that would be very dubious (for one thing, gravity accelerates the galaxies as they get close. For another, there's a significant sideways velocity component.) But I agree this article should match Future of an expanding universe better. Art LaPella (talk) 04:25, 17 September 2018 (UTC)