catdynamics | March 3, 2009Sheril over at the Intersection commits a fallacy.
Worse than that, she undermines the rationale for all science in the progress.
In a post over at the Intersection, Sheril makes a variation on an old argument - the "why spend money on space when there is so much that needs doing here on Earth".
Or, specifically: "All I'm saying is, just perhaps--for the time being--we might be better off spending the kind of figures currently invested in large scale BIG 'what if?' projects on more proximate concerns...
My exuberance over the possibility of an eventual planetary census is tempered as this…
catdynamics | March 3, 2009If the US assumes liability for Credit Default Swaps issued by financial institutions, its potential exposure is many times its gross domestic product.
If the US does not take on this liability it risks annihilation of the modern financial system.
The only solution is to seize both sides.
Seriously.
I mean it
Ok, Credit Default Swaps, crudely are bond insurance - give someone a loan, and you can get insurance against the borrower defaulting (it gets more complicated, since there can be payments invoked when other triggers short of default activate, but those are refinements).
Very sensible,…
catdynamics | March 3, 2009ok, I am mightily puzzled by a technical issue and if anyone knows the answer authoritatively, then cough it up:
question is, does the radial non-adiabatic pulsation of δ Scu/SX Phæ stars really not depend on Y?
there are some theoretical papers in the literature, notably Templeton's thesis papers, which find that the period and period ratio in the δ Scu strip is not sensitive to the helium abundance
the pulsational analysis uses Guenther's solar code, combined with the Yale Rotating Evolution Code
now high Y, helium rich stars, are hotter and more luminous at fixed mass and age, but their…
catdynamics | March 3, 2009whee, we make stars go splat again!
what exactly does happen when stars collide,
just ordinary low mass main sequence stars
Glebbeek and Pols A&A 2008 - v 488 p 1007 and p 1017
BSE: binary stellar evolution code - Hurley et al 2002 from Tout et al 1997
- mass is wrong,
- lifetime is wrong,
- luminosity is wrong
If you are using the BSE prescription for merged stars.
Other than that it is pretty good...
We are adding two stars, M1 and M2 with M1+M2 < 2.5 solar masses
assume near parabolic collisions with velocities at infinity small compared to stellar surface escape velocities;…
catdynamics | March 3, 2009as you know, we're in the opening round of the decadal survey, prioritizing astronomy research and facilities for the next decade - I occasionally suspect all of astronomy has shut down while all of us either write or read white papers and policy documents on some subfield or another...
anyway, Julianne over at CV came up briefly for air to summarize what is going on
what she said.
catdynamics | March 2, 2009so, as you may have heard, AIG, the insurance giant "lost" $61 billion and change this last quarter...
welll, I found it, I think,
but I can't be sure, since it could be someone else's $60 billion, I mean one big pile of used $20s looks much like another;
anyway, the US taxpayers are going to cover AIG on this one,
so "finders keepers", eh?
and the tens of trillions in Credit Default Swaps that the major ex-investment banks are carrying on their balance sheets
they're also mine,
well most of them,
I think Goldman Sachs got some too
it was such a deal, I mean the odds were ridiculously good
I…
catdynamics | March 2, 2009once, when the Net was young, I made the mistake of doing an image search for "Miranda",
in class.
It was a natural enough a mistake, a student had asked a question about the moons of Saturn and I recalled a recent NASA image which illustrated the point I wanted to make.
Try it.
the class got a bit of an eyeful for a brief second, and a good giggle while I rapidly narrowed the search and found what I was looking for
I, of course, being an adult and stuff, have "Safe Search Off" normally.
Although that was a class computer and had generic preferences set. To "Off" I gather.
I'm not squeamish…
catdynamics | March 2, 2009is it worth blogging about science?
one of my doubts about blogging is that it really ought to be more about science
I worry when I see my ratio of random entries creep up, fillers, random rants, political stuff
but I am not terribly interested in being a conduit for press releases, or in doing gee-whizz lay person outreach, or even in patiently explaining the basics - for one thing those niches are already filled by competent and interested bloggers
so while on my current visit to the Kavli Institute, having it as part of my task to blog an ongoing workshop on an actual focused research…
catdynamics | March 2, 2009is that I will agree to take on a major administrative role of some sort
and find that I actually like it...
actually, I fear that I would like it, yet not actually be any good at it
I suppose it wouldn't be so bad if I liked and were good at it
ok, so that isn't really my greatest fear: I mean it is not up there with a giant asteroid hitting the Earth, or a bankrupt financial institution losing $60 billion in a quarter and getting bailed out by the taxpayer or a giant pandemic with high mortality rates
but, on a personal, career scale; it is definitely way up there
catdynamics | March 2, 2009monday, again, already?
we get more fresh blood, and contemplate new topics
some interesting preprints out there on astro-ph:
the Bologna group has hi-res spectroscopy of old LMC clusters, and they see the dreaded Na-O anticorrelation there also! ref
Aargh, there is no escape...
the Sweigart and collaborators have an interesting letter doing combination log(g) and photometry of EHB stars in M3.
They say no helium enrichment ref
PS: hmmmmm - so, what happens if stars with higher Y lose more mass on the RGB?
Could there be a conspiracy to come out at near constant L?
Aargh!
Ok, that would…
catdynamics | February 27, 2009Ed continues, and does case A, B and C mass transfer.
Conservatively, mostly.
From an NWU crowd talk at CfA
For conservative mass transfer, mass and orbital angular momentum are conserved.
If you let mass leave the system, as it often does, and carry away some specific angular momentum, as it will, then things get more complicated.
So: M = M1 + M2 is constant
generally M1 >= M2
q = M2/M1
Jorb = M1M2 √ (G a/M1 M2) is constant
semi-major axis changes a/ai = (M01M02/M1M2)2
Since is is conservative, dM2/dt = - dM1/dt
and (1/a)da/dt = -2dM1/dt (1/M1 - 1/M2)
start mass…
catdynamics | February 27, 2009have you ever wondered what it is that graduate students do?
yeah, me too.
Well, know you can find out, from the horses' mouth
thursday afternoon was dedicated to a rapid fire "so, what have the graduate students been up to" as five of the students here at the program gave presentations on their research projects and what they've been up to in the last few weeks
good practise for them, and a learning experience all round
no pressure, just because about 87.3941% of their likely future employers were in the room, the atmosphere here is very collegial and laid back
Sourav on "Disturbed Blue…
catdynamics | February 27, 2009Is the title of the talk Juan Maldacena gave thursday morning.
I missed the live delivery, due to my deplorable inability to be in two different places at the same time, but, as always webcast video and podcast are here
Enjoy.
Ok, it is string theory, but Juan always gives good talks.
Or he did the other time I saw him give a talk.
catdynamics | February 26, 2009to the Astronomy Unit of the SB Natural History Museum, and the UCSB Circus of Physics
good show
but, guys, next time calculate the EMF first, or even just do a dry run, taking the head off the physicist's daughter would sooooo not have been a career move...
worked out well as it happened though
catdynamics | February 26, 2009there was a legal case in Iceland a few years ago, it was an convoluted property rights case, can't remember the details, but it involved who had ownership when there was delivery but no payment nor explicit assumption of ownership and then a third party intercedes
anyway, the interesting thing about the case, is that it was decided on precedent case law, from a case from about 1000 years earlier
having a continuous constitutional and common law with an extended history can be quite enabling
the Vikings were mostly traders, rather than raiders, and property rights were quite important,…
catdynamics | February 26, 2009so apparently insurance conglomerate giant AIG is on the verge of bankruptcy, again, despite something of order $200 billion bailout from the US, which now owns 79.9% of the company
the news solution is to request the US government guarantee the outstanding CDS that AIG issued
I propose a solution
So, AIG is "Too Big To Fail" - they have too many pension annuities, hold trust funds for progeny of the political elite, and other critical social functions
AIG also, apparently, has enormous one sided exposure to Credit Default Swaps.
When people started taking out very low premium insurance on…
catdynamics | February 26, 2009FSP tells it like it is: where there is nothing for money, and the lads are expensive
pay cuts, btw, are globally a bad idea, even if they are tempting locally
they are massively deflationary, because the cut generally all goes to discretionary spending, - a university doing cross-the-board pay cuts of faculty and staff will trash the economy of most college towns
catdynamics | February 26, 2009yesterday I missed the post-Newtonian discussion, which is a bummer, but I was busy explaining to a hoard of pre-Ks why Mars looked green...
so now we go back to blowing things up
yes, it turns out that not all whites are the same, and trying to project onto that shade of white which has just a tint of blue in it, is not the same as your eggwhite screen, when using an RGB projector.
I should have riffed on Kim Stanley Robinson, I guess, but I didn't.
Look!
Hubble Space Telescope! Astronauts! Rockets! Aliens!
Today, we return to massive binaries and long GRBs in particular, which lets me…
catdynamics | February 24, 2009CR has a fascinating video from KCET on "trashout"
the poingancy and waste that comes from foreclosure and peoples' inability to cope
video is here
the waste, the trashing of furniture and equipment and items is horrendous,
but the cost in labour of slowing down and sorting through the stuff, and partitioning it and storing it and making sure it is safe and clean is prohibitive
there might be crowdsourcing solutions to this, but the liability issues probably preclude any formal or informal organized scavenging - if nothing else, if they put out a note for people to come help themselves,…