back to article Astroboffins discover that half of the Milky Way's matter comes from other galaxies

Up to half the atoms in the stars, planets, moons – and even in us – could come from distant galaxies beyond the Milky Way, according to a new study. Daniel Anglés-Alcázar, coauthor of a paper to be published in the Monthly Notices of the Royal Astronomical Society and a postdoctoral fellow at Northwestern University in …

  1. jake Silver badge

    Given that no matter to speak of ...

    ... is or has been manufactured in our local galaxy, and given that the portion other than hydrogen was pretty much all manufactured in stars, and is pretty evenly distributed amongst the hydrogen, I'd say that ALL of the matter in the Milky Way came from other galaxies. Lex parsimoniae[1] & all that.

    [1] Occam's razor, for the illiterate amongst all y'all.

    1. allthecoolshortnamesweretaken

      Re: Given that no matter to speak of ...

      What do you mean, illiterate? My parents were married, I've seen the papers!

    2. Chris Miller

      Re: Given that no matter to speak of ...

      All matter and energy was once contained within the 'big bang', as was all our space-time, so it's correct (or at least, not wrong) to say that the big bang occurred within the local galaxy (and within your living room, too). All of the hydrogen and most of the helium we now observe was a product of the big bang (some helium has been created in thermonuclear processes within stars, and some is the result of nuclear decay of heavy elements created in supernovae) as was some of the lithium. The observed ratios of these elements in the universe provides strong evidence for the existence of an initial big bang.

    3. Zog_but_not_the_first Silver badge
      Boffin

      Re: Given that no matter to speak of ...

      Why the downvotes peeps?

      1. Rich 11 Silver badge

        Re: Given that no matter to speak of ...

        Why the downvotes peeps?

        Because you confuse several ideas, draw a flawed conclusion, and then come across as a knob-end for trying to sound like Boris Johnson.

        1. Tikimon
          Devil

          Re: Given that no matter to speak of ...

          Don't overlook calling non-Latin speakers illiterate!

    4. GruntyMcPugh Silver badge

      Re: Given that no matter to speak of ...

      Where did you learn astrophysics?

      Elements heavier than Hydrogen, and most Helium, have been produced in stars, Stars fuse Hydrogen and Helium into heavier elements, then they go supernova, and spread heavier elements around. Kepler observed a supernova in our galaxy.

      Where do you propose all the other matter came from? Why is it produced in other galaxies, and not our own? What is different about the stars in our galaxy, in your mind? Do they no fuse elements? Do they not go supernova?

  2. pdh

    A model is not a discovery

    So they created a mathematical model and in that model, half of our galaxy's matter came from other galaxies. That's different from what I usually think of as a "discovery".

    1. Rich 11 Silver badge

      Re: A model is not a discovery

      Fair point. This doesn't propose a new idea, but only places an approximate value on the expectation of an existing one based upon ways in which matter may well travel across the universe. That said, I'm quite happy to see the estimate being made.

  3. Schultz Silver badge
    Boffin

    Astroboffins ̶d̶i̶s̶c̶o̶v̶e̶r̶ speculate ...

    Let me recap the scientific method for you:

    (1) Scientists dream up a model that might explain our world ("hypothesis").

    (2) Scientists compare their model with observations and validate or reject their model ("validation").

    If you make a new observation that requires a new scientific model, then you made a discovery. If you create a model that is not validated by observations, as did the authors of the study described here, then you just speculate and all you have is a hypothesis. This project clearly is in stage number (1); there is no discovery.

    1. Del_Varner

      Re: Astroboffins ̶d̶i̶s̶c̶o̶v̶e̶r̶ speculate ...

      And of course, this is similar to the so-called anthropogenic climate change models, except when they find observations that don't agree with their model, they fudge the "adjust" the observations so they do.

  4. Frumious Bandersnatch Silver badge

    so ... many ... folk ... memories

    Obviously, we are stardust. We are golden.

    > We could consider ourselves space travelers

    or a "starman, waiting in the sky"

    > we could consider ourselves space travelers

    Well, a spaceman did come travelling

    > "a computer model of supernovae explosions,"

    Your Galactic tendency to conjugate adjectives is showing

    > kicked out by a powerful wind

    Now you're just taking the piss

  5. Sorry that handle is already taken. Silver badge

    I make it lots, rather than many

    Since the distance between galaxies often stretches over many light years

    Even the nearest star to our sun is many light years away. Our nearest major galaxy, Andromeda, is ~2.5 million ly away.

    1. eldakka Silver badge
      Alien

      Re: I make it lots, rather than many

      Ahh, that's the closest major galaxy. There are at least a dozen satellite dwarf galaxies (like the Megallanic Clouds) within a two or three hundred thousand lightyears orbiting the Milky Way, even more if you look further out.

      But the Milky Way won't be 'stealing' from Andromeda, it will (probably) merge with and become a part of Andromeda, in a new merged galaxy.

      Galaxy cannibalism is normal and natural.

      Right now we are ingesting a dwarf galaxy, Sagittarius Dwarf Spheroidal Galaxy, so parts of it are 'in' the Milky Way (so 0 light years away...) while the core of it is in a death spiral around us in will eventually, a few hundred million years, merge fully into the Milky Way.

    2. Anonymous Coward
      Anonymous Coward

      Re: I make it lots, rather than many

      Given that the paper is going to be published then I think we have to assume that it has some validity but perhaps its meaning has been somewhat mangled in this article.

      The salient points appear to be:

      "computer model of supernovae explosions"

      "models of galaxy formation during the early stages of the universe"

      "takes several billion years"

      "other galaxies, up to one million light years away"

      So it refers to a time when the Universe was quite a bit younger than it is today and when all of the galaxies would have been closer together.

      1. Tom 38 Silver badge
        Gimp

        Re: I make it lots, rather than many

        Ah, the joys of being young and energetic and sucking matter off hot passing dwarfs...

        Wait, what? More dried frog pills please!

  6. Neil Barnes Silver badge
    Boffin

    Since the distance between galaxies often stretches over many light years

    Why, galaxies are almost as far away as the stars are!

  7. Anonymous Coward
    Anonymous Coward

    Oh great, what happens to the galaxy after brexit then?

    1. Rich 11 Silver badge

      We lose access to the Single Galactic Market and all those nice, tariff-free Pan-Galactic Gargle Blasters.

  8. Your alien overlord - fear me

    But

    But where did the matter from other galaxies come from? And why isn't the matter from the Milky Way going to form other galaxies? Or are we at the center (sink hole) of the Universe?

    1. Rich 11 Silver badge

      Re: But

      But where did the matter from other galaxies come from?

      From the clouds of hydrogen and helium produced after the Big Bang. When those early-population stars went nova (very quickly and very violently) they spread their heavier fusion products around, some of it becoming incorporated into later stars. The stars in those original low-metallicity galaxies are theorised to have long since burned out, and indeed none have been observed so far.

    2. Tom 38 Silver badge

      Re: But

      Our galaxy is young, we picked up many small galaxies by running in to them. We'll get picked up by another, larger, older galaxy at some point, probably long after this sun burns out

  9. John Smith 19 Gold badge
    Go

    It's one of those "I'm surprised this has not been tried sooner"

    Obviously people have known that if the only way to make higher elements was fusion then we are all the remnants of supernovae explosions.

    The (potential) surprise is how far away some of those explosions were. As a layman if I'd thought about it at all I'd have expected them to be within our own stellar "neighbourhood," definitely within out own galaxy due to needing to exceed galactic escape velocity otherwise.

    Which apparently quite a lot of matter could.

    The next challenge will be to see if you can prove the origin of those atoms, which I think will be difficult. Still an interesting idea.

    1. DJO Silver badge

      Re: It's one of those "I'm surprised this has not been tried sooner"

      Obviously people have known that if the only way to make higher elements was fusion then we are all the remnants of supernovae explosions.

      You only need supernovae for elements heavier than Iron and the elements heavier than Iron are only found in the human body in parts per trillion. The elements between Helium and Iron are from ordinary boring novae and other unremarkable stellar deaths, only really big mothers go supernova.

  10. Solarflare

    Is it just me, or is this the sort of thing which is usually preceeded by a large sip of your pint and then "Well, technically..."

  11. Nick Ryan Silver badge

    Solexit

    Damn immingrant star matter coming into our solar system. I demand that we leave the galaxy and go it alone, we can negotiate our own matter/energy transfers and don't need no stinking galaxy and it's gravity imposing things on us. Bloody extrasolar bodies think they can boss us around? We'll show 'em who's boss by exploding our own star. That'll teach them.

    1. Roj Blake Silver badge

      Re: Solexit

      Extragalactic immigrants, coming over here with their vital transition elements. It's a disgrace, I tell you!

      1. Destroy All Monsters Silver badge

        Re: Solexit

        The galactic enrichment will be great, I tell you. Why, quite a lot of stars have extragalactic-sounding names already.

        up to one million light years away

        That's smaller than the local group by quite a bit: Local Group

        It basically includes the "dwarf galaxies" around The Galaxy, and yes these are regularly hoovered up for stray materials if not swallowed whole.

    2. John Smith 19 Gold badge
      Joke

      Re: Solexit

      We wants it

      We needs it

      We must have hard Solexit.

  12. Zog_but_not_the_first Silver badge
    Boffin

    "kicked out by a powerful wind"

    I think you'll find out that a wind is the movement of a medium, rather than what's happening here (essentially matter moving through spacetime). Yes, I know, "solar wind" but that's just an analogy too.

    1. Cuddles Silver badge

      Re: "kicked out by a powerful wind"

      "wind is the movement of a medium...

      Yes, I know, "solar wind" but that's just an analogy too."

      No it isn't. Solar wind is movement of a medium. The mechanism that starts it moving is different from wind on Earth, but once it's left the surface of the Sun "wind" is an entirely accurate term for the bulk movement with no analogies required.

      1. Zog_but_not_the_first Silver badge
        Trollface

        Re: "kicked out by a powerful wind"

        I'd like to argue with you Cuddles, but against such a user name I am powerless. You monster!

  13. sitta_europea Bronze badge

    I don't buy it.

    1. Rich 11 Silver badge

      It's free.

  14. Paul Smith

    Was April 1st involved somewhere?

    Galaxies that are closer then stars?

    'Winds' carrying material between galaxies? And what material were those winds made of?

    Up to half the mass of our galaxy having traveled here from other galaxies? Ejected by supernovas?

    So half the mass of our Galaxy should have been ejected outwards as well? Wheer are the trails of matter?

    How often do supernovas happen? Three have been seen from Earth in the last thousand years, so, not very often.

    This isn't scientific, it is just silly.

    1. Cuddles Silver badge

      Re: Was April 1st involved somewhere?

      "Galaxies that are closer then stars?"

      No, that is not suggested in any way anywhere within either this article of the paper it discusses. You've made that up yourself.

      "'Winds' carrying material between galaxies? And what material were those winds made of?"

      Everything. Primarily hydrogen and helium, but the whole point is that they were composed of all heavier elements as well.

      "Up to half the mass of our galaxy having traveled here from other galaxies? Ejected by supernovas?"

      Yes.

      "So half the mass of our Galaxy should have been ejected outwards as well?"

      No. As the article clearly states, the flow is primarily from smaller to larger galaxies. Since the Milky Way is the largest galaxy within the distances in question, any outwards flow would have been significantly smaller, although no doubt there was still some transfer.

      "Wheer are the trails of matter?"

      Between the galaxies. Aside from the intergalactic medium being far too tenuous to actually observe such a flow directly, the article clearly notes (again, you did actually read it, right?) that the study was about the early universe which wouldn't be expected to be the same as today.

      "How often do supernovas happen? Three have been seen from Earth in the last thousand years, so, not very often."

      That's extremely often. We're not even dealing with geological time here, but astronomical. Something that has been observed happening many times locally in the tiny span of modern human history will happen a hell of a lot over the course of several billion years. Secondly, you've again missed the part about the study looking at the early years of the universe; early, low-metallicity stars had much shorter lifespans so the rate of supernovae was much higher at the relevant time. Finally on this point, your number is just plain wrong, probably by an order of magnitude or more. In the last thousand years there have been three supernovae recorded for which we've been able to identify the remains with modern observations. Far more events have been recorded that almost certainly were supernovae but that we can't now prove, and many others would have been missed entirely.

      "This isn't scientific, it is just silly."

      The paper in question is scientific, your nonsensical rambling that bears no relation to either the paper or the article you're commenting on is silly.

      1. Paul Smith

        Re: Was April 1st involved somewhere?

        "Since the distance between galaxies often stretches over many light years, "

        To a normal person, 'many' usually means less then three digits. Since all but a few stars are considerably further then that, this suggests galaxies are closer then stars.

        The size of the galaxy does not affect the number of supernova and as a large galaxy, we have more super nova then a small galaxy. 3 Observed supernova in a millennium even at 100% efficiency, and you are talking between 100 and 1000 solar masses. Lets pick a nice round figure, say 0.58 solar masses a year. In the life of the universe, (1.3x10^10 years) supernova may have moved 7.5x10^9 solar masses, which is just over 1% of the estimated mass of our galaxy (5.8x10^11 solar masses).

        Looks like somebody can't add...

        1. Tom 38 Silver badge
          FAIL

          Re: Was April 1st involved somewhere?

          Looks like someone is making a ridiculous argument to stay "right" on the internet. "Many" meaning less than 1000, get a grip.

        2. Anonymous Coward
          Anonymous Coward

          Re: Was April 1st involved somewhere?

          @Paul Smith

          I think you should stick to Fashion, Science doesn't quite seem to be your cup of tea...

        3. Cuddles Silver badge

          Re: Was April 1st involved somewhere?

          "To a normal person, 'many' usually means less then three digits."

          No it doesn't.

          "The size of the galaxy does not affect the number of supernova and as a large galaxy, we have more super nova then a small galaxy."

          I like how the first half of the sentence directly contradicts the second half. "Large galaxies don't have more supernovae, therefore our large galaxy has more supernovae". Classic. Maybe you realised just how stupid the first part actually was halfway through typing.

          "Looks like somebody can't add..."

          Looks like someone hasn't read the paper they're flailing around trying to criticise. Instead of pulling random numbers out of your nether regions and whining about how something you don't understand isn't science, try reading what it is the science actually says.

          1. Paul Smith

            Re: Was April 1st involved somewhere?

            You are right. I didn't read the as yet unpublished paper. I read the El reg article about the paper and that is what I commented on.

            The maths do not come close to adding up.

  15. Alistair Silver badge
    Joke

    Heard around the black monolith

    Oh my god, its full of galactic farts.

  16. Sorry that handle is already taken. Silver badge

    Hmm

    I've noticed that many of the "mainstream" media outlets, even ones that should have a better understanding of science, seem to be reporting on this that life on earth (or even humans!) came from another galaxy.

    What.

  17. dnicholas Bronze badge

    This is scientist code for "we have no fracking idea how this works, have some CGI"

  18. John Smith 19 Gold badge
    Coat

    Once again some of the most exciting (or frightening*, depending on context) words in science

    "I did not expect that."

    Which usually means that in some quite small segment of the global knowledge base of facts we call science things are about to get interesting.

    *Like when you've underestimated the output of your desktop fusion device by a million and you realize it should have been tested inside a concrete bunker about 10 miles away from any people, instead of in your office.

  19. adam 40 Bronze badge
    Paris Hilton

    The big bang didn't happen in my living room...

    ... it happened in my bedroom! (Tra laaa)

    Anyhow it only seems logical that panspermia would come along for the ride with the wind from the other galaxies, so yes, life probably came from somewhere else, billions of years ago.

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