layer8 22 hours ago
withinboredom 6 hours ago
Thanks. Cloudflare took so long to determine whether or not I was bot-shaped that I just came to the comments.
rob74 13 hours ago
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...

thaumasiotes 8 hours ago
> Also, in diagrams showing our galaxy, I would greatly appreciate a "you are here" marker which points out the location of our solar system...

What would that mean?

Try locating France on this map: https://en.wikipedia.org/wiki/File:T_and_O_map_Guntherus_Zin...

rob74 8 hours ago
Ok, I would be happy with an approximate location too. On that map, I would place France in Europa right beside the mediterraneum, pretty much on the Occidens side (although not at the very edge).
thaumasiotes 7 hours ago
Well, to ask you again, what do you think "an approximate location" would mean? How would the labeling be done?

It's easy enough to take the rob74 position of "I'm going to choose an arbitrary point on this artist's conception and paste a 'you are here' sticker over it", but what would be the point?

wvbdmp 6 hours ago
Well, we’re clearly not in the center, for one thing.
kridsdale1 4 hours ago
It’s right where the V (Latin U) symbol is.
dotancohen 22 hours ago
Is this a non-sequiter or just poorly phrased?

  > 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.
eventualcomp 15 hours ago
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.

malfist 21 hours ago
When does "starting in the center" mean anything besides "starting in the center"?

The earth is not the center of the galaxy

furyofantares 15 hours ago
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.
assimpleaspossi 19 hours ago
He didn't say that. He said earth is nearer to the center of a spiral arm.
malfist 15 hours ago
What does the center of a spiral arm have to do with the center of the galaxy?
assimpleaspossi 7 hours ago
I don't know but that's not what I'm talking about.
dylan604 16 hours ago
the location of earth has precisely zero to do with the topic
assimpleaspossi 7 hours ago
And your reply has zero to do with what I'm talking about.
happytoexplain 21 hours ago
I actually am not following what the ambiguity is - stars farther out from the center are younger, no?
kadoban 20 hours ago
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.

rafram 15 hours ago
The father out from the center of the galaxy they look, the younger the stars are.
jibal 14 hours ago
The location of the Earth is completely irrelevant. "closer" and "farther" refer to the center of the galaxy.
two_handfuls 4 hours ago
They don't mean that the stars migrate out (then further stars would be older), they mean that stars further away from the center start forming later (so further stars are younger).

I agree that the phrasing can be confusing.

_factor 22 hours ago
Poorly phrased. The most recent stars are on the edges. The inner stars were first, hence the “working outwards”.
kakacik 10 hours ago
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.

Ekaros 9 hours ago
You need certain density to start formation progress. Then you get more density as it drags more stuff via gravity from intergalactic void. So new stars form at edges when there is finally enough stuff pulled by gravity of whole galaxy to there for the formation to happen.

It seems that you need quite large concentrations(as in scale of whole universe average) to actually get to star formation. Otherwise stars would be uniform trough the universe.

Then again I am not astronomer.

ww520 20 hours ago
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.
JumpCrisscross 20 hours ago
Try: "the farther out [from the center] astronomers look"
jibal 14 hours ago
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.
furyofantares 15 hours ago
From Earth (where astronomers are) looking "out"ward (away from the bulge).
colechristensen 22 hours ago
It is beyond obvious what they mean.
neals 22 hours ago
Just the daily post that makes me feel small and insignificant.
dylan604 22 hours ago
I prefer that feeling much more than the modern sense from social media where everyone is abnormally important
rambojohnson 16 hours ago
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.
chirau 9 hours ago
How are claims like these verified?
kridsdale1 4 hours ago
Looking up.
onchainintel 15 hours ago
Incredible. "Hi honey, what did you do at work today? Casually discovered the edge of the galaxy. How are you?"
ordu 12 hours ago
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.
hulitu 8 hours ago
I'm still searching for the location of the Restaurant at the end of the universe.
mrsvanwinkle 2 hours ago
It's not a search problem it's a grammar problem: https://pages.cs.wisc.edu/~param/quotes/guide.html
TZubiri 9 hours ago
Oh thank goodness, I've been looking for that.
yrcyrc 22 hours ago
Great. Next Laniakea