> Disk galaxies like the Milky Way form stars “inside-out” — starting from the center and working outwards through the disk. So, as a general rule, the farther out astronomers look, the younger the stars are.
Do they meant looking out from Earth (which is actually nearer to the center of a spiral arm than to either end) or out from the galactic bulge. Either way doesn't make sense.
But why? Star forms when enough hydrogen (or maybe also helium) clusters together with gravity to spark fusion IIRC. The center of Milky way ain't some ultra dense place where stars are just trillions of kms from each other to support somehow earlier star formation.
Or did ie dark matter/energy somehow coalesce on the outer edge later? Milky way is supposed to be very old place, almost as old as universe itself so one would expect more homogeneous distribution, at least as a layperson.
Looking from Earth at the stars closer to the center of a galaxy, they are found to be older. Looking from Earth at the stars closer to the edge of a galaxy, they are found to be younger.
To use an analogy, to add to everybody else: it's like rings on a tree stump. The innermost part of the stump is the oldest; the outer the youngest. Earth is on one of those in-between rings, neither the oldest nor the newest - doesn't matter which of the in-betweens, to be honest.
Suppose now that you're an ant on the middle ring of that tree stump. No matter which way you're looking from Earth's middle-ring, either the rings will get gradually older and then younger with increasing distance (if you're looking towards the center-ish), or the rings will get strictly younger (if you're looking away from the center-ish).
This analogy obviously breaks down if you delve into details but that should give a better intuition to what's going on.
Earth isn't relevant. The stars at the center of the galaxy developed first, and development proceeded from the inside out, so the youngest stars are on the edge ... then they get older from there on out, as the stars beyond the edge broke away from the galaxy. The bottom of the age U is the location of the formative edge.
Seriously. Being meaningless and insignificant gives you more freedom, and nowhere to hide from what you do with it. I’ve never understood cosmic dread. It feels like a release valve instead of a threat.
I think they have been looking for the edge for years, and the discovery had come gradually over some time. So I don't think that "casually" fits there and "today" doesn't make things better.
Better, adblocker-friendly article (original press release): https://www.um.edu.mt/newspoint/learn/2026/theedgeofthemilky...
Paper: https://www.aanda.org/articles/aa/full_html/2026/04/aa58144-...
Title: "Astronomers find the edge of the Milky Way"
First sentence in the article: "Astronomers have located the edge of the Milky Way’s star-forming disk for the first time"
Wouldn't you expect someone from a publication called "Sky & Telescope" to know that these two are different things?!
Also, in diagrams showing our galaxy, I would greatly appreciate a "you are here" marker which points out the location of our solar system...
Looks like leaving the solar system was just the tutorial level。 Next main quest:breaking out of the Miky Way.
Is this a non-sequiter or just poorly phrased?
Do they meant looking out from Earth (which is actually nearer to the center of a spiral arm than to either end) or out from the galactic bulge. Either way doesn't make sense.
It is beyond obvious what they mean.
Poorly phrased. The most recent stars are on the edges. The inner stars were first, hence the “working outwards”.
But why? Star forms when enough hydrogen (or maybe also helium) clusters together with gravity to spark fusion IIRC. The center of Milky way ain't some ultra dense place where stars are just trillions of kms from each other to support somehow earlier star formation.
Or did ie dark matter/energy somehow coalesce on the outer edge later? Milky way is supposed to be very old place, almost as old as universe itself so one would expect more homogeneous distribution, at least as a layperson.
I actually am not following what the ambiguity is - stars farther out from the center are younger, no?
The Earth isn't the center of the galaxy, so this feels confusing/confused:
> So, as a general rule, the farther out astronomers look, the younger the stars are.
The father out from the center of the galaxy they look, the younger the stars are.
The location of the Earth is completely irrelevant. "closer" and "farther" refer to the center of the galaxy.
When does "starting in the center" mean anything besides "starting in the center"?
The earth is not the center of the galaxy
He didn't say that. He said earth is nearer to the center of a spiral arm.
the location of earth has precisely zero to do with the topic
What does the center of a spiral arm have to do with the center of the galaxy?
The Earth is where the astronomers are. If they are looking outward (away from the center) then the further they look, the younger the stars.
Try: "the farther out [from the center] astronomers look"
Looking from Earth at the stars closer to the center of a galaxy, they are found to be older. Looking from Earth at the stars closer to the edge of a galaxy, they are found to be younger.
To use an analogy, to add to everybody else: it's like rings on a tree stump. The innermost part of the stump is the oldest; the outer the youngest. Earth is on one of those in-between rings, neither the oldest nor the newest - doesn't matter which of the in-betweens, to be honest.
Suppose now that you're an ant on the middle ring of that tree stump. No matter which way you're looking from Earth's middle-ring, either the rings will get gradually older and then younger with increasing distance (if you're looking towards the center-ish), or the rings will get strictly younger (if you're looking away from the center-ish).
This analogy obviously breaks down if you delve into details but that should give a better intuition to what's going on.
From Earth (where astronomers are) looking "out"ward (away from the bulge).
Earth isn't relevant. The stars at the center of the galaxy developed first, and development proceeded from the inside out, so the youngest stars are on the edge ... then they get older from there on out, as the stars beyond the edge broke away from the galaxy. The bottom of the age U is the location of the formative edge.
Just the daily post that makes me feel small and insignificant.
I prefer that feeling much more than the modern sense from social media where everyone is abnormally important
Seriously. Being meaningless and insignificant gives you more freedom, and nowhere to hide from what you do with it. I’ve never understood cosmic dread. It feels like a release valve instead of a threat.
Incredible. "Hi honey, what did you do at work today? Casually discovered the edge of the galaxy. How are you?"
I think they have been looking for the edge for years, and the discovery had come gradually over some time. So I don't think that "casually" fits there and "today" doesn't make things better.
Great. Next Laniakea