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12:51 AM
@TimB: well 3.4k rep doesn't mean ~10 avg rep / answer if you got close to 1k rep on a single answer :P
 
1:24 AM
btw, when does @bowlturner usually pop in here? :)
 
2:07 AM
@ArtOfCode Mi Yodeya has an independent Twitter account. We tweet questions that catch people's fancy, retweet comments others make about the site, and share occasional other on-topic links. (We don't have a blog.)
@bilbo_pingouin huh. You win. :-)
@Shalvenay you can get some hints from the activity graph on his chat profile.
 
 
1 hour later…
3:14 AM
@HDE226868 and this is what it would look like from a planet with atmosphere? Cool! (All those NASA pictures of colored nebulas -- usually reds and blues -- made me think the colors weren't real but there was some sort of color-shifting going on for the photos.)
@HDE226868 so, once I figure out the type of star, is the color pattern deterministic? (We're talking about a star sitting inside a reflection nebula. It's part of a binary system; the planet orbits the other star.)
I can ask this as a question on the site; the reason I asked here first was that I didn't know if it was a "duh, obvious" thing that would make for a boring question.
 
 
8 hours later…
11:04 AM
A note for whoever does the next topic challenge - it might be worth reserving some editorial judgment and using this challenge idea instead of the top-voted - it's time-sensitive and won't happen again for another 4 years.
3
 
11:24 AM
0
Q: Should Worldbuilding set up a Twitter account?

ArtOfCodeA number of Stack Exchange sites have their own Twitter accounts, which are controlled by a bot that tweets hot questions. Some sites on the network have decided they don't like this, and have created their own independent Twitter account for the site, which is controlled by a group of humans wh...

 
11:56 AM
Any more questions for the Will Hicks panel?
@MonicaCellio I think it would be a worthwhile question - we already have some stuff about sky inside a nebula though so read that first :)
 
12:23 PM
@ArtOfCode we can still wait for the next challenge... actually that would sound better
to have the leap day in the challenge
:)
 
@bilbo_pingouin Aye, that's what I mean. Next one starts tomorrow, so we can just pick that one instead.
 
no I meant, next one starts tomorrow... we can pick whatever stands at the top
the following starts on the 15th
so the 29th will be within the challenge
 
12:58 PM
makes sense to me
 
1:39 PM
by the way, @ArtOfCode, the current challenge is based on two tags. Does your script handle that?
now that I write the question, I seem to remember discussing it before. But if so, then sorry I forgot.
 
2:01 PM
@bilbo_pingouin I think it does. When I checked it looked like it should do, anyway.
If not, someone'll have to use it twice, once for each tag, and then cross-check the lists.
 
the thing is that I'm not sure what was the intended rule anyway... should the two tags be used together, or should either would be fine?
 
Either, I think.
 
probably a question to @James ^^
 
2:17 PM
0
Q: World Under Ice Questions Too Broad?

Tim BI've noticed a series of questions all closed as too broad: The Ice of Eurasia, in Full Detail The Poles, Great Lakes Earth If the Laurentide Ice Sheet Swallowed More of North America The Neo-Tethys Sea, in Full While they are all quite broad (and cover a big chunk of land) I don't agree tha...

 
2:32 PM
@MonicaCellio Some of those are false-color photos taken in other wavelengths (infrared, for example). Infrared and UV photos tend to look the most realistic when transformed like that; radio, x-ray, and gamma-ray photos don't look too real.
But yeah, quite a few are real-color visible wavelength photos.
@MonicaCellio I'm not sure. It depends a decent amount on a star's color, so a white or blue star (think O or B) embedded in a reflection nebula might make the nebula a bit bluer.
But it also depends on the composition of the nebula.
So yeah, asking a question on the site might be good.
It's definitely not an obvious question.
In general, by the way, these nebulae are biased towards being blue.
 
 
4 hours later…
7:00 PM
@HDE226868 it looks like I have to work out my star types first, and then I can ask this question. :-) This started with one of my questions about the binary-star system, where I posited a G-class primary star and an unspecified secondary star that I wanted to be bright (but not planet-crushing) and you suggested the reflection nebula. Gamma Cephei, is K- and M-class; I don't know if that could support human-like life.
This article suggests that F, G, and K are promising, but that only addresses unary stars. Hmm, I guess I have a question brewing before my nebula-light question.
 
K-type stars aren't too different from the Sun (G-type). Life could be supported by that. I would be a bit worried about the M-type dwarf. Aside from the low luminosity issue, red dwarfs are sometimes prone to strong flares that can be detrimental to habitability.
At 10 AU, though, that shouldn't be an issue.
In a binary star system, F, G, and K stars are still fine, provided you keep the planet in the habitable zone of the primary.
 
I am a bit more open minded regarding life-supporting stars. "Stars must be yellow" reminds me a little about "Why do meteors always land in craters?"
or "Why is the eye's peak wavelength sensitivity equal to the Sun's peak output wavelength?"
 
7:18 PM
@HDE226868 thanks! Yes, I want a primary star with a planet in the habitable zone and a second star bright enough to light up that planet too (nebula-aided is fine, and in fact neat so even if I don't need it I'd want to keep it). M struck me as not bright enough even with the nebula assist; didn't know about the flares.
 
Oh, so I finally got somewhere on an answer to my stars-without-nuclear-fusion question, and guess what: The Kelvin-Helmholtz mechanism is really the best shot. I completely forgot about T Tauri stars, which can spend ~10$^8$ years contracting on the Hayashi track before joining the main sequence. All I have to do is extend that by ten.
@MonicaCellio Yeah, M-type dwarfs aren't my favorite because of that. They're not terrible, just occasionally dangerous. Other M-type stars aren't on the main sequence (e.g. red giants, red supergiants, and some related ones like AGB stars and some subgiants).
 
like polar bears
 
@Hohmannfan "life" is broad; perhaps it's a weakness of mine, but I tend to reach for "human-like life" because it seems easier to connect with readers. A really talented writer could make readers connect with the intelligent denizens of M-class systems, that resemble humans not at all, but I'm not that good yet. :-)
 
@MonicaCellio That is OK, there is a reason that 99% of all books focus on the Earth, not the rest of the universe.
 
@HDE226868 Got a link to the answer?
 
7:22 PM
@HDE226868 heh, didn't know about the cloud cover there.
 
@MonicaCellio In fact, most of those Earth-books tend to focus around that tiny crust
 
@TimB I haven't posted it yet; I'm only halfway done.
What I need to do is add some mass loss and replenishment via some mechanism like a souped-up accretion disk.
 
ok, cool. If you can when you can :)
 
@Multiple @conversations @pinging !
 
I'd be interested to read it
 
7:24 PM
@TimB I'll see when I can finish it. There's a decent amount of writing to do, because I have to work out how the star will oscillate above and below the plane of the disk.
 
@Hohmannfan yeah, I want a world that is Definitely Not Earth, and I want to play with the effects of having the two stars on the residents. I don't just want this to be "Joe Generic-Human transplanted to this other place", but I don't want to start from scratch describing the mind, habitat, and society of my lizards or whatever, either.
 
And I have to figure out a mass loss mechanism and figure out how to estimate accretion rates. I may end up posting a mainly qualitative answer first and then updating it with some order-of-magnitude calculations.
 
If anyone is interested in a worldbuilding project centred around a red dwarf, I stumbled upon this: worlddreambank.org/L/LIB.HTM
In fact, the whole collection of worlds is something to look at: worlddreambank.org/P/PLANETS.HTM
 
7:57 PM
posted on January 31, 2016 by Tim Boura

Welcome to a new concept for Universe Factory. In this blog post a panel of people are going to work together to deconstruct my recent… Continue reading on Medium »

2
 
8:09 PM
1
Q: What would this nebula look like from a planet?

Monica CellioI have a binary system. The primary star is F- or G-class; the secondary is K-class, 20AU away, and in a small reflection nebula (suggested here). A planet orbits the primary in the habitable zone. This article suggests that F, G, and K classes can all support habitable planets; it's talking a...

 
8:54 PM
@MonicaCellio Yeah, I was the first upvote.
 
@HDE226868 :-)
 
1
Q: How would the night sky appear from the inside of a Star Cluster?

GreyGaminIn some star clusters, the stars are packed as densely as a light year apart or less. Many clusters do not appear to have black holes in the center, though they remain relatively stable in their orbits and longevity. Assuming a cluster about 100 light years across, and planet(s) cable of suppor...

^ Oh yeah.
Wish we could close as a dupe of the Astronomy question, though. They're virtually identical.
Should I just re-work the blog post into an answer?
 
9:23 PM
@HDE226868 sounds like a good approach, yeah (with link for more, if you like). You've already done the work, after all!
 
9:34 PM
@MonicaCellio Okay, yeah, I basically did that.
 
10:05 PM
@TimB Maybe I can post a qualitative-ish version by this time tomorrow.
 

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