The h Bar

David Z

1:20 AM

Chat session tomorrow! (15 hours from now)

Crazy Buddy

1:34 AM

Cool ;-)

David H

1:56 AM

Random physics history trivia du jour: Ernst Mach's name has a rough ancient Germanic meaning very close to "Rigorous Mechanics". As a fan of his works in the history and philosophy of classical mechanics, this is amusing me to no end at the moment. =D

user54412

3:49 AM

@tpg2114 omg I <3 latex

tpg2114

I like it when I do normal things with it

I don't like it when it fights me

user54412

@tpg2114 also, if you find an answer to this, welcome to thermonuclear supernova modeling - at which astro department would you like your Einstein fellowship?

tpg2114

@ChrisWhite I found an explanation so I'll submit my resume ;)

user54412

just make sure you account for neutrino transport ;)

tpg2114

That's too complicated for my work... thank goodness

user54412

3:55 AM

@CrazyBuddy I have a new mistress - her name is "thesis research" and she is quite high-maintenance

user54412

@tpg2114 would you believe that Type Ia supernovae (the very ones certain people got the Nobel prize for using to prove the universe's expansion is accelerating) are still unknown in terms of what they are?

tpg2114

What do you mean? Like the materials they are made of? Or how they form? Or what they do?

user54412

by process of elimination, we say "probably a white dwarf involved" but then no one is sure whether the explosion is pure deflagration, deflagration->detonation, mostly detonation, etc

user54412

or if there are two white dwarfs or just 1

user54412

or what they are made of

tpg2114

4:03 AM

How can they not tell if it's deflagration or detonation? Isn't it possible to observe the reacting material and the speed it is moving?

user54412

ahh - nope ;)

tpg2114

But not because of temporal resolution limits right :)

user54412

lol no

user54412

Type Ia's only become visible many days after exploding, when the ejecta fills a larger volume and is heated by Ni-56 -> Co-56 -> Fe-56 decay

tpg2114

How is it not visible? There's gotta be some energy emitted that's observable during early times

user54412

4:06 AM

well, if one went off in our galaxy, sure

user54412

problem is, that may only happen once every century or three

user54412

but you can bet if one did, every telescope on Earth and in orbit would point at it for at least 2 months

tpg2114

So it's more an issue of lack of observation... We'd have to happen to be looking at the right place at the right time

Or have already mapped that region of the sky so we could go back and see which star exploded if we happen to notice it later

user54412

indeed, and we're trying to get better on both fronts

user54412

actually, one of the collaborations I work with recently got a paper on arxiv while the supernova was still getting brighter - that's pretty much a first for these things

user54412

4:09 AM

and what's more, there are some Hubble images of the host galaxy

user54412

but while we can see massive stars in nearby galaxies, it's nearly impossible to see a white dwarf even in Andromeda

tpg2114

So you're where I am in some ways -- cook up artificial initial conditions in the hopes you get a later state correct and use those fake initial conditions to speculate what the real processes are

user54412

exactly :)

tpg2114

I'm scrambling to get all my work done, not going so well

I was living in my lab for 3 days, nowhere near enough time though

Didn't help I spent my morning arguing here... haha

user54412

the internet - such a trap

tpg2114

4:19 AM

Indeed

l3win

4:38 AM

Can anyone recommend me a good book on advanced topics in Combustion?

tpg2114

@l3win How advanced? And from what perspective? Theoretical, numerical, experimental?

Are you looking for turbulent combustion, laminar?

l3win

4:59 AM

I'm looking for something that covers chemical kinetics in details actually.

I guess it should therefore cover turbulence as well

Crazy Buddy

12:23 PM

@ChrisWhite Well, I can make her go in less time... Just ask away your question (and don't forget to add the bounty) :D

Anonymous

1:31 PM

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