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 …
... 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.
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.
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?
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.
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
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.
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.
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.
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.
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.
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.
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.
"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.
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.
"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.
"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...
"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.
"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.
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