Friday, April 28, 2006
So, you want to be an astrophysicist? Part 2.5 - grad school
It is safe to talk about grad school again...
You're in grad school. Yay.
Now wtf do you do...
Well, you need to jump through the hurdles first.
Most places have some course and seminar requirements, you may in some cases test out of them or waive them, but think about whether you really want to. Odds are that your undergraduate curriculum was not complete or advanced enough in at least some areas. Yes, you want to get on with research, but you also want to be solid on the fundamentals.
Take the stoopid exams, whatever they call them, usually some variation on candidacy or comps or both.
Most places admit students they expect to pass, a few have a policy of admit everyone and then flunk whoever out, most don't.
So, trained experts have determined you have the innate capability of most likely passing those exams, with a bit of work. Or possibly shitloads of work. So just do it.
Take seminar courses. They are usually on the "hot topics", and usually very good.
As a grad student I liked to take classes, real classes (mostly math, I still want more math) and seminars, up through my final year. A lot of students want to be done with classes as soon as possible, a lot of advisors think classes are a waste of time and dilute research efforts. I disagree, but not strongly.
GO TO TALKS!
Seriously, and I don't just say that because I'm in charge of colloquia.
Every place has some mix of formal colloquia, informal lunch talks and meetings.
Go to as many as you can stand. Especially at the beginning and at the end of your time. And in the middle...
The colloquiua are usually either "hot topic" talks, or major reviews of sub-fields. Lunch talks are more likely "in progress" talks. Either way you ought to want to hear about it. This is what the faculty think is hot, was hot recently or will be hot soon.
Go especially if it is outside your sub-field, you might learn something!
Introduce yourself to the speaker if possible. Go to lunch or dinner or coffee, or meet formally, if you can. Be nice.
These people will often remember you, they may be your future employers, or friends of your future employer, they are virtually certain to be reviewing a proposal or something of yours eventually. Astronomy is a small field and people talk.
While you're at it - if you have the oomph, go to stuff outside your department. University wide talks, seminars, things in other departments, even classes. A friend of mine in grad school claimed he could eat for free 5 days a week by attenting the right pattern of seminars and colloquia (not recommended, you can live on cookies and chips and coffee, but not well).
Ok, research. Yes, you should do some.
If you know what you want to work on, get going on it as soon as you can.
If you don't know, start exploring around as soon as feasible.
Go talk to faculty. Mostly they don't bite.
DO NOT ASK ABOUT MONEY! If you're doing it for money, then you're in the wrong business.
Ask to do research you are interested in doing.
Do your homework first, check the web page, glance through a paper or three. If you are not interested in doing research, you know, exploring the universe, adding new knowledge to mankinds inventory of nature and technology, then you should not be doing a PhD.
It is possible that what you think you're interested in is not suitable (in the stoopid profs opinion) for PhD research... it may be done, wrong, not interesting, undoable or just not interesting enough. The Prof may be wrong, but the word "advisor" has a meaning. You want to be advised, take it under consideration.
Try again, or ask for input or both. Some people have lists of projects to do, some people have some general ideas, and some people want to hear what you think. Radical thought.
If the answer from a potential advisor is "no" don't take it personally, and maybe try again, faculty have external lives that may preclude working with students or on particular projects at any given time.
If the project is good, a lot of the time money will be found...
Being a research assistant is good, but it won't kill you to be a teaching assistant for a while. You should be a TA for at least 6 months anyway. If you hate teaching, find out early in grad school, not when you become faculty!
If the department permits, or encourages it, then try doing a research project in a sub-field that is not what you think you want to do for a thesis.
Think very seriously about whether you want to do theory, observation, data analysis or instrumentation.
You may end up doing things you never imagined out of necessity (like theorists go take observations, cause if they don't no one else will; or observers running simulations, or building the instrument they need to do the observations etc etc).
Do you have the aptitude? Do you have the background? Can you learn?
Career goals should matter some, think about whether you want to stay in research? In academia? Industry? Observatories? NASA?
You want to pick up certain skills and experiences depending on which is your primary focus. Be ready to be disappointed, the competition is fierce. But most PhDs end up in some combination of interesting or well paid jobs. Opportunity cost is usually recovered even if you end up doing something other than you planned.
It is worth thinking about the medium term future of your chosen sub-field; is it expanding, new faciltiies coming online, is it peaking, or in decline? BUT, predicting the future is futile, particularly now. I don't know anyone who could confidently tell you which sub-field will see growth in the next decade. JWST is the biggest bet, if it launches and works.
Survey science and database mining look promising; so do mm-wave obserbations; I also suspect computer simulations will be a growth field again - BUT, if you had asked me 1-2 years ago my predictions would have been different and very, very wrong.
Pick and advisor you can get on with. Scientists are often "characters". Way high up on the list of "things you do not want to do" is being stuck with a PhD advisor you do not get along with.
BUG YOUR ADVISOR.
Er, but first make sure you pick an advisor who likes to be bugged...
There are two kinds of advisors - those who meet formally with students and expect progress; and those who bump into people in the corridor and blearily say "oh, you're working with me, right? Well, so, how is it going then...?"
KNOW YOURSELF: if you need the push of regular progress reports, then don't sign up with a hands-off advisor.
If you do want to bug your advisor, bring something to the meeting: progress, news, an idea, a question, a complaint. Something.
Self-motivate: particularly if you work with a hands-off type. Everyone procrastinates, but you're not going to have your hand held in most departments, you fizzle out, you're finished (eventually, when someone finally notices).
You're supposed to be working on new original stuff that you find interesting. So do it.
Finally: READ!!! Pro-actively. Check arXiv regularly and thoroughly. Read the papers relevant to you and anything else that looks interesting.
Read the references! They are there for a reason.
Read the citations - if a paper is interesting, papers which cite it are also likely to be interesting. Use the ADS "C" option liberally and look through it quickly.
If in doubt ask you advisor, or just read it anyway.
Next, the slightly tricky issue of what we actually "do", research wise type of thingy. Might take a while...
Fractal Dust Sims
Explicit numerical modeling of dust aggregates from sub-micron grains, in the presence of short range non-Coulomb forces is an excellent short term student project; 6-12 month starter in numerical simulations. Fun, high risk, but potentially interesting.
Offered it a couple of times, no one bit.
'Course getting funding to do it properly could be a bit tricky. Not much in "blue sky, wild idea" research nowadays.
Maybe it could be sold as nanotech, understanding dust chain formation in microgravity to safeguard space qualified electronic components...
iPod iChing - Anomalies at 70 μ?
So, Mighty iPod dood, we will do the easy topical question, and ask: are the "strange things happening" at around 70 microns in the Adleberger experiments actual signs of non-Newtonian deviation on small scales?
Whoosh goes the randomizer.
- The Covering: Toy Symphony 3 - Mozart
- The Crossing: La Fourmi Amoureuse - Henri Dés
- The Crown: Black Wind Blowing - Billy Bragg and Wilco
- The Root: Ihr eingeweihten Diener der Gotter Osiris und Isis - Mozart
- The Past: She's Got a New Spell - Billy Bragg
- The Future: Bakaradrengur Syngur - Thorbjorn Egner
- The Questioner: I Won't Share You - The Smiths
- The House: Can You Swing Your Arms? - Twin Sisters
- The Inside: If I Didn't Love You - Squeeze
- The Outcome: Nicaragua, Niacaraguita - Billy Bragg
Well, that doesn't look good.
The Future is the "Song of the Baker's Boy" in which the recipe for "pepper cookies" goes badly wrong (but in way critical to the plot, to be fair).
The Questioner is a bit scary.
The Outcome is a celebration of a revolution, which is curious.
The House clearly things this is just handwaving games...
The Inside reflect the motif of the Questioner answer. Yikes.
The Crossing is frivolous but The Crown is somber...
The Root is intriguing!
The Past really says it all:
The laws of gravity are very, very strict
And you're just bending them for your own benefit
So, ambiguity and obsession.
The Past would seem to say no, but the Outcome if revolution?
I don't know what is going on.
As always, the Key as explained by Sean
Thursday, April 27, 2006
Most are contradictory
Therefore most, or all, are wrong.
There are three kinds of theorists:
- Those who are right
- Those who are wrong for the right reasons
- Those who are "not even wrong"
This is of course not a unique decomposition, there is also this one, which is near orthogonal to the previous one:
There are three kinds of theorists:
- Those who think they are right
- Those who "shut up and calculate"
- Those who are interesting
Also, as I tell the "Stars for Poets" class: science is not an adversarial process, but scientists often are. (journalists please note)
Hm, does that mean the Napoleonic Code is an emergent property of the Common Law...?
Fractal Dust, LEDs and Cracks in the Cosmos
Dust aggregates formed in microgravity aboard the CODAG Shuttle experiment.
Micron sized SiO2 spheres rapdily aggregated in microgravity into low dimension fractal structures (Blum et al "Growth and Form of Planetary Seedlings: Results from a Microgravity Aggregation Experiment," Phys. Rev. Lett. 85, 2426 (2000). )
Physics News Update 775:"...At the APS meeting, Eric Adelberger, leader of the Washington group, summarized some of the other efforts underway in his lab such as the search for evidence of extra dimensions in the form of departures from Newtonian gravity (for instance, the inverse-square dependence) at a size scale of tens of microns. In fact, he said that something strange was happening at a measurement scale of about 70 microns; the most likely explanation of this, he conceded, was an experimental artifact."
So, a few years ago I did something whacky but fun.
Each year the Gravity Research Foundation runs an essay competition.
It is nice opportunity to indulge in some speculation that may not be mature enough for an actual fer reel letter, but is worth thinking about, a little bit.
So, back in 2001, I was thinking about fractal dust.
The Blum et al paper had just come out, and I had just come back from the Cosmic Genesis and Fundamenal Physics Workshop at Sonoma, so I was just freshly updated on the Large Extra Dimensions speculation...
Now, at the time there was a bubbling puzzle in planet formation, namely how Neptune and Uranus ever got started during the lifetime of the solar system, the timescaled inferred for aggregation were just too long, the gas and dust disk would be gone before planet formation got under way. (This is a non-problem now, best bet scenario is that Neptune formed much further in and was scattered out at early times, but it motivated the chain of thought).
So... thought I, that's funny.
IF micron dust grains are fractal, with low effective dimensions, then grain growth is rapid, and almost mass independent at low mass.
And, lo and behold, they are fractal, with effective dimension ~ 1.3.
Ok, neat. But, how could that be?
Well, one explanation is that when sub-micron grains aggregate, they see a strong non-Coulomb force at small radii, and coalescence is at high specifical angular momenta. This naturally leads to open, fractal structure growth, for a while, until impacts start compactifying the "dust bunnies". (see below)
Cool. Well, we can calculate that, and there are several candidates (van der Waals forces, heterogenous temporary free charge etc etc), but why not look at non-Newtonian gravity on small scales.
So, we plug'n'chug, and this works, for 2 Large Extra Dimensions, and a effective radius of curvature (this also works in Randall-Sundrum theory) is about 80 μ
So, I wrote it up, sent it to GRF, got an honourable mention, and IJMPD 10.6 781 publication.
Also got a writeup by Marcus Chown in New Scientist, and again with the even whackier follow up on Bose-Einstein condensates and Large Extra Dimensions
The interesting thing is not the planet formation, it is whether the fractal dust formation really is due to non-Newtonian gravity and hence "predicted" a n=2 Large Extra Dimension deviation at less than 100 μ.
So... maybe Adelberger is not seeing an experimental artifact.
We can hope, would make life a lot more interesting.
Oh, and I still think something like the BEC stuff would work, but maybe people can tell that I am not an actual experimental designer kinda person...
Experimental hints of Gravity in Large Extra Dimensions?
Recent conjectures suggest the universe may have large extra dimensions, through which gravity propagates. This implies gross departures from Newton's law of gravity at small length scales.
Here I consider some implications for particle dynamics on scales comparable to the compactification radius, $R_c \ltorder 1$ mm.
During planet formation, coalescence of micron sized dust grains to planetesimals is a rate critical step.
Blum et al (2000) found dust grain aggregates form low fractal dimension structures in microgravity, consistent with high angular momentum coalescence.
I consider the effects of non-Newtonian gravity on dust aggregation on scales less than $R_c$ and show they naturally coalesce into low dimensional structures with high specific angular momentum.
We infer $R_c \approx 80$ microns.
out till fall...
Well we got no choice
all the girls and boys
Makin' all that noise cause they found new toys.
Oh we can't salute ya
can't find a flag
If that don't suit ya
that's a drag.
School's out for summer
school's out forever
School's been blown to pieces.
No more pencils
no more books
No more teacher's dirty looks.
Well we got no class and we got no principles
And we got no innocence
We won't even think of a word that rhymes.
School's out for summer
school's out forever
school's been blown to pieces.
No more pencils
no more books
No more teacher's dirty looks.
Out for summer
out till fall
We might not come back at all.
School's out forever
school's out for summer
school's out completely.
Wednesday, April 26, 2006
Where would you put the comma?
But, this sentence needs a comma.
"But beyond the snarky implication that Fox News has become the semi-official network of the Republican Party lies the reality that Fox has been far more successful than the White House communications office at packaging a vision in which Bush is a hero."
Where would you put it, before or after "lies"?
Latter option does leave the sentence slightly incomplete in interesting ways.
On The Proper Subject Order in High School
A furor arose in the letter pages, debating the merits endlessly. Which first, which last? (also here).
Now, I think we can all agree on the basics - there are not enough resources to teach all subfields each year of high school, and I am told scheduling is also impossible if people are taking subjects for more than two years (one year intro, one advanced for college hopefuls). So, decisions have to be made.
I have thought about this, and I think that having general phys ed as grounding in the first year is essential; then basketball, because it requires the least amount of equipment to set up; then baseball; and leave football to the final year. Your typical high school student is not ready for football before their final year anyway, playing it earlier just invites injury.
Now, people argue that the final year should be general phys ed, and that football should be taught first, no later than sophomore year, so that the top players can do a second AP year to prepare for college, which they must do no later than junior year for consideration by the top programs. Now this may be fine for private prep schools, but the realities of public education, and the difficulty in finding qualified coaches clearly precludes this. Maybe the largest schools can do junior level football, or allow exceptional players to play a year early, so they can get a second year before college, but realistically the fraction of players which have the innate talent to compete at the next level is so small that it is simply not an issue for most schools.
A friend of mine suggested leaving general phys ed to the middle schools, and moving all athletic classes up a year; then the advanced students aiming for college would have time to take senior AP classes, maybe even two or three sports for the absolute top athletes, in schools with the resources to offer that. Then, the regular students could take Driver's Ed in their final year, which is when it is most needed anyway. This could be a good compromise, particularly for the larger urban schools.
What puzzles me is, having come through the European system, how they managed to do everything from shooting and archery, to yoga, through soccer, hockey and rugby, and still manage the scheduling. Even in a relatively small school. Must be some ineffable structural difference in the education management system.
The Real Problem
I guess that means the DoE goal is halfway accomplished.
Given enrollment trends, though, we need to know if journalism profs could teach "stars for poets"?
I mean, I know Bérubé can but we expect versatility from the JoePa Professor.
Could your average Bob Jones University Media Studies Prof really handle "Charles Messier’s late-eighteenth century catalog of stellar objects"? I don't think so... I mean, dude was French!
PS: everyone MUST READ comment #36 in Bérubé's article by "Grumpy Physicist". Priceless.
"If you transform the original opinion (call it ’x‘) by making a parody, we can write this as:
x’ = P x
where ’P‘ is the “parody” operation. Now from all possible opinions, one can construct linear combinations that are eigenstates of the operator P (the proof is trivial, and left as an exercise for the student). That is, x’ = a x, where a is a constant. And since a parody of a parody gets one back to the original state, PP = 1, and thus allowable values for a are +1 or -1.
Most sensible opinions have a=-1: when you parody them, you invert their sense.
There must exist, however, sets of opinions that have a=+1; that is, they are ‘invariant under the parody operation’. When subjected to parody, the parodied opinions are indistinguishable from the original opinion."
- Grumpy Physicist
Damn. I wish I had written that...
Tuesday, April 25, 2006
Musical Links to Enjoy
Monday, April 24, 2006
Avian 'flu - maybe not so mild after all
Argument, simply put, is that only acute cases were being diagnosed and those are necessarily the ones where the patient is in danger of dying, so the mortality rate is artificially inflated by selection bias. We only know of the sparse really bad cases.
If only, the argument goes, we did a random sample of a population where a case had been found, we would likely find many asymptomatic or mild cases that never came to medical attention.
Or, unfortunately, maybe not...
Not definitive but curious.
Good news is then, that the H5N1 strain really has a hard time spreading; the bad news is that it is very lethal. As is.
SALT Big Time
First Light: 47 Tuc
WaPo put The South African Large Telescope on the front page.
SALT is an 11 meter segmented optical telescope, optimised for spectroscopic surveys in the optical.
Design concept is based on the venerable Hobby-Eberly Telescope (with some engineering learning experience passed along...).
The key aspect to HET and SALT are that they are basically fixed telescopes which use the secondary to track targets over
a relatively limite range in azimuth and declination. So you sacrifice flexibility but gain light gathering power and cost.
The construction costs, for the size of telescope, is an order of magnitude lower than a full two-degrees-of-freedom telescope.
The telescopes are somewhat limited in both the range of targets they can reach in the sky, and the time they can stay on target, but they are big light buckets and work well for large scale spectroscopic surveys and synoptic spectroscopy.
HET, for example, has been doing steady work doing spectroscopic followup of Sloan and Chandra targets, as well as planet hunting (which requires high resolution synoptic spectroscopy).
Friday, April 21, 2006
I Need to Read
| So Good! :D|
You scored 72% Best Seller and 71% Classic!
|Oh, yes, somehow you made it. Did you cheat? I hope not. Sophocles is reported to have said, "I would prefer even to fail with honor than to win by cheating." Meh, I'll trust you this time. Anyway, I hope you've had a good time.|
|My test tracked 2 variables How you compared to other people your age and gender:|
|Link: The Book Character-Savvy Test written by Vorpal_Bunny on Ok Cupid, home of the 32-Type Dating Test|
Grr. 87th percentile by age and gender on Classics.
50th percentile on Best Seller.
Glad that at least it wasn't the other way around.
Must. Read. More. Again.
iPod iChing - Varying μ?
Busy, busy friday. So, we ask the obvious question...
iPod - is the effective mass ratio of the electron to the proton actually varying on cosmological time scales?
Whoosh goes the randomizer.
- The Covering: Bad Penny - Billy Bragg
- The Crossing: Staldraðu við - Stuðmenn
- The Crown: Eric the Half A Bee - Monty Python
- The Root: Nature Boy - Nick Cave and the Bad Seeds
- The Past: Can You Swing Your Arms- Twin Sisters
- The Future: Oh Well - Fiona Apple
- The Questioner: Lilli Stríðir Refnum - Thorbjorn Egner
- The House: Late Night, Maudlin Street - Morrissey
- The Inside: Litirnir - Edda
- The Outcome: Dammi tu forza, o cielo! - La Traviata
#11 is The Boy Feels Strange - Melissa Etheridge and #12 is Shipbuilding - Robert Wyatt
Oh, man, that results is so not there.
The Crossing is a "hang out and take it easy" kinda laid back tune;
The Crown is just a classic, and so appropriate it boggles the mind.
The Questioner is "the little mouse teases the fox". Heh.
The Inside is "Colours" - a children's song teaching people about wavelength determination of electromagnetic radiation...
The Future suits.
The Outcome is just eerie...
As always, the Key as explained by Sean
is it worth the effort?
it is the time of year when there are reports of fights and harassment between students. Lot of honking of cars, squealing of tires and overheard mutterings of "fuck".
So... walking back to the office I hear some student screaming abuse - at me it turns out, he didn't appreciate me crossing the road at a marked crosswalk with a stop sign. Slowed him down for half a second I guess.
Now this is a big campus, but surprisingly not actually that big, and he was in a fairly distinctive car. Very distinctive car.
Senior I believe, with a friend.
I was mildly bemused, then a bit angry.
So, is it worth it? Should I followup and let them experience some consequences for being obnoxious assholes?
I don't know if they figured they were safely anonymous, or if they didn't figure someone in jeans and t-shirt would be faculty.
Either way it was a stupid thing to do, but stupid enough to make their lives extremely miserable for a couple of weeks, or do
I just figure it is one of those things and let go...?
Thursday, April 20, 2006
iPod iChing - Furry Black Holes?
Not yet friday, but a quickie, to focus the mind...
iPod, dood, are Black Holes Furry?
- The Covering: I Was Born - Natalie Merchant
- The Crossing: The Flight of the Bumble-bee - Roge
- The Crown: Young Ned of the Hill - the Pogues
- The Root: While My Heart is Still Beating - Roxy Music
- The Past: Once Upon a Time: Storybook Story (them from the Princess Bride) Knopfler
- The Future: I Wanna Be Loved - Elvis Costello
- The Questioner: Scenes from Childhood: Knight of the Rocking Horse - Schumann
- The House: I'm Burning - Jesus Jones
- The Inside: Don't Worry About the Government - Talking Heads
- The Outcome: Accident Waiting to Happen - Billy Bragg
Huh. I will wait to ponder this.
Only one person in the world knows wtf this one is about, intriguing...
Regular service may resume tomorrow.
As always, the Key as explained by Sean
What to expect in grad school
A mini-survival guide for graduate school - less is more, sometimes
That actually makes me feel better.
David Brin always used to say that the only happy people at university were graduate students in stable relationships whose research was going well.
Ok, he only said it about One Particular University. But he had a point.
Are y'all messing about with Google? 'Cause apparently they release earnings tonight...
Or, maybe Google is just Omniscient and Know Something I Don't. Or maybe just desperate.
Google is a Good God.
Something for Lubo
Happy Birthday Matt
Happy Birthday Matt
Rheinold et al Phys Rev Lett 151101, v96 (2006) claim a lab measurement showing that μ = mp/me has changed over time.
They compare measurements of UV spectra of molecular hydrogen in the lab sensitive to the electron/proton mass ratio with redshifted measurements of the same transition (so observed in the optical in the local rest frame), and conclude with 3.5σ confidence that there has been a 20 part per million change in the effective mass ratio.
Well, I believe the lab measurements. The QSO observations were done with UVES on the VLT and are of redshift ~ 2-3 quasars.
Hm, they are measuring absolute wavelengths, so the simplest explanation is that the narrow H2 lines are systematically offset from the lines used to determine the redshift of the complex doing the absorbing - not intrinsically silly, depending on how close they are and what is being measured, haven't tracked down the VLT paper.
File this under "something to keep an eye on", but be skeptical.
this space deliberately left blank
Wednesday, April 19, 2006
True Trilogies You Ought to Read
- Feynman Lectures
- The Art of Computer Programming
- Stephenson's Baroque Cycle
- Lord of the Rings
Sadly the number of theses I have to ready by friday number 4...
Tuesday, April 18, 2006
Oxford Research Group - Iran March 2006
Iranian Nukes: Plain Language version
There is more discussion at Cosmic Variance and Nuclear Mangos, but I wanted to straighten and simplify what I think the key immediate issue is, partly for my own line of thought.
- Iran is a signatory of the Non-Proliferation Treaty.
As such it is entitled to develop civilian nuclear power, and to receive assistance from the nuclear powers to do so.
The assistance may include proliferation safeguards and IAEA supervision.
- Iran has had a nuclear power program for over 30 years dating back to the Shah.
They bought a large (1 GigaWatt) fission reactor from the Russians (current contractor), Bushehr-1. On the gulf coast, it is in a complex that is intended to host more reactors. The Iraqis bombed it in 1984 (several times 1985-88 according to Wiki) I believe; progress on reconstruction was intermittent and it is not yet operational. It is complete, or essentially complete, in construction. What is missing is the fuel - several tons of moderately enriched uranium. The Russians have repeatedly posponed delivery of the fuel.
The Iranians are angry over this, there are huge cost overruns and excessive delays.
The reactor is due to go online, delivering power to the grid in october this year.
To do so, the Russians have either already sent the fuel to Iran, or must to so in the very near future.
The Iranians will need to do some off-line operation to shake down the reactor before it goes online.
That means this summer.
- It is actually sensible for Iran to have a nuclear power program. They are large, need to supply a lot of electricity to their grid, and long term they are better off having substantial baseline nuclear power and sell the oil and gas instead of burning it to produce electricity.
- Both the USA and Iranian internal political situations are such that each assumes the other is operating in bad faith.
Not just "normal bad faith", both assume the other intends a worst possible outcome.
Internal political situation in both countries is unusually volatile and there may be play in exacerbating external tensions for internal political leverage.
- Iran has reasons to want nuclear weapons in a hurry, looking at their situation from the outside with a neutral perspective.
They are surrounded by potentially hostile powers, several of which are nuclear powers, and have recently fought a major war in which WMDs were used against them when the opponent was faltering.
The "axis-of-evil" speech and subsequent events suggest that bilateral deterrence is prudent for the axis-of-evil countries.
Contrast the treatment of North Korea with Iraq.
- Over the last 15-20 years, Iran has setup and tested everything they need to have a completely independent nuclear fuel cycle. They can mine uranium. They have tested plutonium production and extraction and done lab scale experiments on plutonium chemistry and matierals science. They have experimented with uranium enrichment and have in construction facilities to do their own enrichment, which can be done to moderate levels for fuel for powers, or continued to highly enriched levels for bomb construction. What they have not apparently done yet is set up production of their own nuclear materials on large scale. They are brushing very close to their treaty committments under NPT but have not made a blatant open breach with their treaty agreements. They're pushing it.
- So: how can you get nukes in a hurry.
- There are three kinds of nuclear weapons:
- Well, simplest way is to buy them.
There are at least three potential suppliers.
This has some problems - you don't know if they sold you a dud unless you test; if you test you better have bought several. which is harder than one, and then the game is also up. World will know, and they will know who sold it to you.
Intelligence agencies ought to be able to isotopically single out where any nuke came from, and I don't think the Iranians know enough to successfully "spike" any test to mask the production signature.
You can't really deter with bought nukes, just retaliate.
- The Big Worry in the media is the HEU bomb, since the Iranians are setting up enrichment.
Now, a moderately wealthy nation with ~ 100 physicists (10-20 good, rest competent); few hundred chemists and engineers (competent) and couple of thousand honest construction workers and machine tool operators, and with large electrical power supply, can go from zero to full HEU production, enough to make many kilograms per year, in about 3 years.
IF the politicians don't micromanage the process, and the technical people are motivated and honest.
With modern management techniques, it would probably take 10 years.
An enrichment facility allows a NPT signatory to cut loose, they don't need a nuclear power to supply part of the fuel loop, they don't have to honour any external reprocessing safeguards. They can either have their own completely internal power cycle, build bombs, or both.
Iran is probably 5-10 years from doing this. It will not get them a bomb this year.
They can do it somewhat quicker if they take commercial moderately enriched uranium and enrich that rather than raw ore.
So, they could divert civilian fuel to their own enrichment plant to make HEU quickly. They could hide or obfuscate the process by mixing unenriched uranium in to make up for the missing bit, leaving less enriched uranium. The reactor should still work, but less efficiently. Risky but they might be able to obfuscate long enough to finish enrichment to HEU levels.
- You can make nuclear reactors that work on natural (unenriched) uranium.
These are somewhat harder to build, the simplest most robust design use "heavy water".
Iran has a heavy water production facility.
IF they built a moderate power HIDDEN nuclear reactor and it went operational more than a year ago, they could have made enough plutonium for a bomb or two, and possibly be producing one-to-few per year.
It seems unlikely they could have done this and gone operational without USA or Israel noticing.
- In my opinion Iran has a window to make several Pu-239 bombs quickly right around now, at a considerable diplomatic cost.
The way they can do this is to get the fuel for Busherh-1 reactor, and after the core is turned on, shut the reactor down early and pull out the partially burned fuel and chemically extract the Pu-239.
This would require an open and blatant violation of IAEA safeguards, a breech of the NPT, and possibly the expulsion of the Russian engineers at the reactor (or their detention or passive acquiescence). It would certainly be noticed.
BUT, if everything else is already in place, the Iranians could then very quickly extract Pu-239 from the partially burned fuel. Enough for something like 3-10 bombs, depending on their efficiency and design capabilities.
Their window to this is the next 3-9 months. If the fuel is in too long it is useless until the next refueling cycle.
IF the Russians have or will soon deliver the fuel for Bushehr-1.
I would be most curious to know if anyone else know for sure whether it has been shipped to Iran.
The Iranians know this.
The Israelis know this.
Probably some people in Washington DC know this. Certainly people in some other particular locations in the US know this.
IF you fear Iranian intentions, and assume worst case scenarios, this scenario rationalises a pre-emptive strike, before the Iranians have the opportunity to do a fast burn at Bushehr-1.
Since you might as well be hung for a sheep as a lamb, any strike then escalates to a full pre-emptive knock-out against all identified Iranian nuclear facilities.
Fission bombs made with highly enriched uranium [HEU] (>> 80% of the U-235 isotope, natural uranium is 99+% U-238 isotope) - these are moderate yield ( ~ ten kilotons TNT equivalent); this is what was dropped on Hiroshima. They are very simple to make if you have the HEU. They are heavy, and hard to put on missiles.
Fission bombs made from plutonium, specifically Pu-239 (used on Nagasaki). These have low-moderate yield (kiloton to over 100 kiloton). These are harder to engineer, and a new design is thought to require testing if you want to be sure they will work. They can also be "boosted" to somewhat higher yields, testing would probably be required for that. They can be made light and compact, with some practise.
Thermonucelar weapons (fusion or H-bombs). These use fission bombs (Pu-239 type) as triggers to start much more energetic (fusion) nuclear reactions. They are hard to do, and probably not an issue in the foreseeable future. They can be made to have very, very high explosive yield (tens of megatons - thousand times more powerful than fission bombs).
So, realistically, to build nuclear weapons, you need either pure plutonium-239, or highly enriched uranium.
Countries that have become nuclear powers have used both techniques. The associated engineering is not trivial, but it is solved, fairly well known and just not that intrinsically hard. It is literally 1940s-50s technology.
Most of the media focus is on Iran's announcements on uranium enrichment, in part because of the implications for the long term, in part because it is being played up by analysts and pundits, and in part because it is how Pakistan got their bomb, and they aided Iran covertly.
To make Pu-239 you need a working nuclear reactor (a big one is better, higher throughput).
You put unenriched or depleted uranium, rich in U-238 isotope in the reactor (either in the core, or around it in a "blanket").
If you keep it in a short time (~ 3-4 months or less) neutrons from U-235 fission "breed" U-238 into Pu-239.
If you keep the uranium in too long you get Pu-240 and Pu-241 which "poison" explosive fission, the bombs either explore incompletely with low yield, or possibly detonate spontaneously without a trigger.
For efficient power production you want the fuel in the reactor for a long time, and separating Pu-239 from Pu-240 is very hard. Separating Pu-239 from U-238 is quite easy, it is chemistry. It can be done quickly if you are willing to take moderate risks.
So, how could Iran get nuclear weapons?
The political and economic consequences would be very bad. Potentially catastrophic.
Quite frankly, I think the US internal reaction would be a severe schism, while the Iranians would unify.
US political pundits seem to think the opposite, that the Iranians would schism and overthrow the current government while the US would consolidate around the government.
This is why I am seriously concerned that the US may launch a pre-emptive air strike on Iran in the near future.
Oh, I get the sense that the DC "beltway pundits" have become accustomed to thinking of airstrikes as "no big deal". With Iraq from 1991-2003 having repeated small airstrikes, and the bombings in the Balkans in the mid-90s, there seems to be some perception that Iran could just sock it up and accept that the US might choose to send a few squadrons of heavy bombers over. No biggie, grouch about it for a few weeks maybe, some transient market panic, what the call a trading opportunity in Congressional staff offices. (Hm, be interesting to see if oil and gold futures are trading from laptops in DC at anomalous levels).
It is a big deal. Iran is kinda prickly about the whole thing, and nations that are on the receiving end of pre-emptive large air strikes traditionally count it as Acts of War. Ye Olde All Out War, not these late twen-cen half-ass wars.
It would not be fun at all.
- Well, simplest way is to buy them.
This is an anecdotal, selection biased peeve, but...
A lot of children's books have pictures of the crescent moon, from the context it is clear that the setting is early evening in the northern hemisphere, so it must be a waxing moon.
So wtf do more than half of them (anecdotally) have the crescent pointing to the right?
Is this some art aesthetic?
This is so trivial, yet so easy to do right with negligible extra effort.
And then we wonder why "Stars for Poets" students have a hard time understanding the geometry of the phases of the moon, they've been subliminally indoctrinated since birth to see the moon with the wrong crescent. Assuming they actually read books back then.
One of these days:
I've been dicing-with-death all semester carrying the laptop balanced on top of my folder to and from class. Today it finally took a dive to the floor... case is dinged, DVD drive is making worrying nosies, and the battery now claims to be good for 80+ hours (I could be onto something here). But it still works, for now.
I already knew that carrying the 12" Dongle in my back pocket was not a good idea; earlier this semester I sat on it and bent the "green pin". Fortunately my lecture notes look pretty good in magenta.
iTunes theme of the day - alternating Violent Femmes with Billy Bragg's International (extended play version).
And I have four senior theses to read in 3 days. Oo-ja.
Monday, April 17, 2006
assuming ~ 4 years mean time per grade, and an "up-or-out" policy, I estimate ~ 50-100 retirements per year.
About half of those should be Army and USMC officers.
Parsing the data more finely, something like 10 2-star Army generals retire each year. USMC is about 1/3 the size of the Army.
These numbers scale linearly with the change in assumptions about time in grade etc.
BUT... how could the media and US public possibly take seriously a comment that it could be "used to make anthrax or smallpox"!?
Now, I ain't a biologist, and I ain't brave enough to make stuff like that without something more solid than canvas around me; but how could any half-educated person seriously think that anthrax and smallpox were both possibly produced in these things.
The two are nothing alike.
NASA: Long Term Sod All
Anyway, short version:
NO LTSA - ever, if I parse the message correctly
ATP and BEFS share a pot, which is 30% or so smaller.
No word on ADP. (Let me know if you hear anything).
NASA solicits a number of "unsolicited proposals" each year (these are open, anyone can apply solicitations - as opposed to the "you, you and you (or just You) - give us a quote for this here particular Giga$ project Now, Please).
Mostly these are done through the ROSES omnibus solicitation.
Now, most solicitations are "mission specific", some mission funded is "guaranteed" to center researchers, or scientists who did instrument development etc. This comes with funding.
The "great observatories" have their own "guest" proposal rounds, independent of the ROSES, where you can apply for time (including archival and theory work, though the theory budgets range from zero to tiny). With time, comes money (see it is true!). This is a signficant funding line for university and external researchers, but, it is spotty, haphazard and spread thin.
It is, for example, very hard to put together multi-year funding for a postdoc researcher from any one Hubble observing project (only the very largest, and rarest, proposals have enough money to pay for ~ 3 years of postdoc). And since competition is fierce, it is hard, and unpredictable, whether any given researcher or team will have back-to-back proposals to roll science staff over from year-to-year.
Enter ROSES. Some of the key lines of ROSES research are the LTSA, ADP, ATP and Foundation Science proposals.
These are NOT mission specific, they need to be relevant to NASA, in some cases must be NON mission specific, or specific only to future planned missions (especially the Foundation Science stuff).
They are also typically multi-year; 1-3 years typically, except LTSA (Long Term Space Astrophysics) which is usually for 5 year projects.
LTSA is also valuable because a significant part of the funding is set aside for junior researchers. This typically either allows senior research associates to self-fund for multi-year projects, or for junior faculty to get a serious research program going before tenure (it also helps in the transition, senior postdocs with LTSAs often quickly become faculty hiring postdocs for the last 2-4 years of the funding!). LTSA is also one of the "tickets" junior faculty want to get stamped to get tenure...
LTSA is long term, as close to "blue sky research" as NASA does.
Now, last year LTSA applications were temporarily suspended for a year with the then budget squeeze.
This year, it was re-suspended, then put in limbo pending review, and now apparently it is reviewed, and...
It is now dead.
I suspect three problems; it costs money, something like 1% of the current projected cost overrun for the Crewed Exploration Vehicle each year.
It is a long term committment, it reduces funding flexibility in the out years, where the budget projections are even worse.
And, it is not tied to missions, it is planning for the future. And, NASA is not planning any science missions for the future, so why do research on that stuff?
So, it is, according to reliable sources, cut. Gone. Dead. Or maybe it is just sleeping...
PS I am told that looking at "technology solicitations" in the current proposal round is interesting.
These are split between lots of different sub-divisions, so getting the overall picture requires work.
I have heard this work has been done, and there is a 70% cut in technology development for future missions.
ie there is not technology development for future missions now, essentially only late stage implementation of current tech for missions in the pipeline is being done.
But, since no new missions are planned this of course does not matter.
I mean a decade from now NASA can just press a red button and Staples will deliver some brand new bleeding edge tech space qualified and ready.
It must be true, I saw it on television.
NASA: boring meetings
I am informed, anecdotally, but from someone who ought to know, that: NASA will no longer sponsor science meetings at "resort locations"!
It is not clear to me if this is specific to one or some divisions within the Science Missions Directorate, or if it is agency wide, but either way it is a stupid idea.
At least one meeting in Hawaii has already been cancelled, allegedly because of this new policy. At a very substantial cost to the organisers because of lost deposits, by the way.
This is stupid for many reasons, not the least of which is that essentially all of Hawaii is a "resort location" by any definition (and, no, I do not know what definition is being used), and Hawaii is a good location for astro and space meetings. For one thing it is one of the few places where you can actually see the stars.
I would think the good Senators from Hawaii would have something to say about this, it will cost Hawaii and the University of Hawaii plenty.
However. Scientists get really jaded about meetings. There are a lot of them.
To get people fired up and to the meetings it helps to have them in interesting locations. It is not necessary, it just helps.
But, interesting locations are also where a lot of hotels and conference facilties are found. Universities are also often at interesting locations.
Stupid. Stupid enough it almost has to be true.
"Penny wise, pound foolish"
Some engineering still to be done on packaging, the blue phosphor could be longer lived, but they appear to have good spectral energy distributions, high application flexibility and very high efficiencies. Like cut 10+% of grid electricity consumption efficient. Every bit helps.
Manufacturing costs need to come down, which should come with scale of production; expect early adoption "gizmo" users will be having some within a year or two.
Friday, April 14, 2006
Talking With The Taxman About Poetry
iPod iChing - hidden fields
Whoosh goes the randomizer. Whoosh.
- The Covering: Waiting for the Great Leap Forward - Billy Bragg (Live Bootleg)
- The Crossing: New Year's Day - U2
- The Crown: The Few - Billy Bragg
- The Root: Black Wind Blowing - Billy Bragg and Wilco
- The Past: Suffer Little Children - The Smiths
- The Future: Dial-A-Cliche - Morrissey
- The Questioner: Litla Kvæðið um Litlu Hjónin - Davíð Stefánsson
- The House:I've Been Working On the Railroad - Twin Sisters
- The Inside: Four Sticks - Led Zeppelin
- The Outcome: Ofboðslega Frægur - Stuðmenn
#11 is Good Shit by Cornershop and #12 is V Rondo - Mozart...
The Outcome is "Extremely Famous" by the best classic rock group Iceland has produced. A somewhat sardonic ode to the "ordinary guy" we all knew in school who became a Big Shot but still acts folksy.
The Questioner is a very damning poem about the little lonely old couple who grew apart - because they had no children. The moral of the story is ambivalent, you can conclude either that the children were essential, or that the whole thing was a mistake.
The Root is spot on, and The House is appropriate as it so often is... The Past is just horrid...
Extra bonus points to those who figure out wtf this question was about...
As always, the Key as explained by Sean
Hann er einn af þessum stóru,
sem í menntaskólann fóru
og sneru þaðan valinkunnir andans menn.
Ég sá hann endur fyrir lögnu,
í miðri Keflavíkurgögnu,
hann þótti helst til róttækur og þykir enn.
Já hann er, enginn venjulegur maður,
og hann býr, í næsta nágrenni við mig,
og hann er alveg ofboðslega frægur,
hann tók í höndina á mér, heilsaði mér
og sagði: KOMDU SÆLL OG BLESSAÐUR
(ég fór gjörsamlega í kút)
Hann sagði: KOMDU SÆLL OG BLESSAÐUR
(ég hélt ég myndi fríka út)
Hann hefur samið fullt af ljóðum,
alveg ofboðslega góðum,
sem fjalla aðallega um sálar líf þíns
Þau er ekki af þessum heimi,
þar sem skáldið er á sveimi
miðja vegu milli malbiksins og regnbogans.
Já hann er enginn venjulegur maður...
Við ræddum saman heima og geyma,
ég hélt mig hlyti að vera að dreyma
(en ég var örugglega vakandi).
Mér fannst hann vera anzi bráður,
hann spurði hvort ég væri fjáður
og hvort ég væri allsgáður og akandi.
Já hann er enginn venjulegur maður...
Thursday, April 13, 2006
Negative Security Assurance
In order to provide incentive for non-proliferation, the nuclear power states offered a negative security assurance, that as a matter of treaty they would not use nuclear weapons on non-nuclear signatories of the NPT (with some fuzziness, like allies of nuclear powers could be attacked [ie a Soviet armoured division crossing Poland was not safe even if Poland was a NPT signatory], and more recently, bio and chem weapons might receive nuclear retaliation).
By threatening pre-emptive nuclear strikes on an NPT signatory, not as retaliation for an attack violating the treaty, the US has effectively destroyed negative security assurances (and this was not an empty promise, the US refrained from nukes in Korea and Vietnam, the French did not use nukes, nor did the Russians in Afghanistan or the Brits against Argentina).
So, why would anyone now honour the Non-Proliferation Treaty?
It seems clear that with the new policy, the only "safe" course is for each nation to get a deterrent quickly. This is the first lesson of the post "axis-of-evil" world.
And there are 10-20 nations who could so so very quickly, and another 10-20 who could with a very major effort.
And, while there is some marginally stable equilibrium for bilateral mutual assured destruction between sane players, finding stable equilibra for multiplayed MAD scenarios is hard. Impossible if one or more player is not rational.
I do not want to see nuclear weapons used in anger on the planet I live on.
More on Iranian Nukes
Few more comments:
the Russians supply Iran with their technology, under the NPT.
The Bushehr reactor dates back to the Shah's rule. It is late in part because
the Iraqis bombed it in 1984 (if I recall correctly).
The fuel for Bushehr is supposed to be returned to Russia for reprocessing
to prevent plutonium extraction and is supposed to stay in the core for a year or longer to make sure the Pu-239 is contaminated with Pu-240 and Pu-241.
If Bushehr-1 is fueled and turned on, and the Iranians then block or expel the IAEA, with the acquiesence or expulsion of the Russians, then they can have bomb grade Pu-239 in 3-4 months by doing a short burn which creates minimal Pu-240/241. This is inefficient for power production, good for bomb making.
Depending on how good their design is, a 4 month run could make enough Pu-239 for 3-10 bombs, and same again every 4 months until they run out of fuel. If they can do their own enrichment, or if they build heavy water reactors, then they never run out of fuel to breed plutonium.
If they learned the plutonium chemistry from their lab experiments in the 90s, then they can get metallic Pu extracted, cast and machined very quickly. Weeks.
This is why the situation is escalating, Bushehr is supposed to go on the grid in 6 months. That means they must load the fuel now, and start test runs.
It would mean open defiance of IAEA and the UN, but that is right where the Iranians are headed now.
U-235 fission bombs, with yields up to some tens of kilotons of TNT equivalent are easy; you make 2-3 sphere segments, keep them apart and shoot them at each other inside a metal tube when you're ready. Boom.
If you try that with Pu-239, according to reliable sources, it squibs. It goes partly critical faster than it can assemble into a sphere, and the heat pushes the plutonium a part. You get a very incomplete explosion, with bits of melted and burned plutonium metal. Messy and mostly useless.
Similarly too much Pu-240 or Pu-241 in you plutonium and it can't be assembled without going critical prematurely, possibly spontaneously.
The way around that is to have a small plutonium core, with the remaining segments in spherical shell, like the skin of a soccer ball. Then you implode the segments onto the core using high velocity explosive in a simultaneous and very symmetric implosion. Tricky, but straighforward. Require fast detonation, high velocity, pure explosive (which can be bought); and fast switches (which can be bought) - this is 1940s tech.
This gives you controllable yield over maybe a factor of 10-100 without much fuss.
If you want much broader yield range, or very light compact warheads, or something that will trigger thermonuclear fusion reactions, then you need good engineers and some experiments (or experience for hire). 1950s tech.
If you want something that will make a very big boom as deterrent to attack or invasion, which can be installed as a mine, or in truck/ship, and you don't care if it is dirty due to incomplete burn or "only" 10 kilotons instead of 30 kT, then you're done.
Just churn them out one or two per month as long as the reactor runs and the labs are open.
Several actual issues are coming together, only one of which is the US internal political situation.
The Iranian government is acting as if it intends to exit the NPT and go nuclear.
The Iranians have completed the technology development to go indenpendent of the NPT signatories and can do the full cycle internally without relying on Russian fuel supply or reprocessing.
The Bushehr reactor is finally due to actually go on line full of moderately enriched uranium which could be used for quick production of an initial batch of bombs. This has been delayed to the point that the Iranians ought to be seriously annoyed about it, the reactor should have been on-line several years ago.
It seem neither side is negotiating in good faith.
Wednesday, April 12, 2006
Tale of a Tremendous Cheddar...
Iranian Nuclear Speculations
I don't know Iran; I don't have access to any classified information on nuclear weapons.
I do know something about physics...
First of all, Iran is clearly been working on putting together a full nuclear cycle for about 20 years
That means they want to be able to do it all in-house: mining, enrichment, burning, plutonium extraction, power generation and bomb production.
It is clear that they did the science in the early-to-mid-90s, they tested centrifuges, built small high neutron flux reactors and got small amounts of plutonium extracted.
So, they learned Pu chemistry, what isotopes you get with different burns, and maybe some metallurgy.
They then set up centrifuge halls and played with an AVLIS (laser isotope separator).
They also ordered a 1GW reactor from the russians, and refined uranium oxide (aka "yellowcake") into both uranium tetrafluoride, uranium hexafluoride and uranium metal.
Supposedly several tons of uranium oxide were processed.
Now: there are two ways to make bombs, at the basic level.
Get highly refined uranium-235 metal; or, fairly pure plutonium-239. In kilogram quantities.
U-235 bombs are simple and need not be tested. "A grad student could make one of those".
Pu-239 bombs are notoriously fickle and are said to need testing (although maybe not so much any more...)
If you want to go on to thermonuclear weapons, then you want Pu-239 production, and either some genuis level physicists assisted by good engineers (of which Iran has plenty), or help from someone who already figured it.
So... the claim is that Iran is about a decade away from having a nuclear bomb.
This is not necessarily true for several reasons.
What is probably true is that Iran is about a decade away from having a totally in-house bomb production line capable of providing everything for "many" bombs per year.
For that you want lots of yellowcake, a high power reactor to breed plutonium, and a refining facility to supply the reactor.
You use the U-238 rejected from the enriched U-235 to breed plutonium in a neutron absorbing blanket around the reactor,
and you use the enriched U-235 to keep the reactor going. You can spin off some power either through dual use reactors (what the USSR and UK did) or purpose built faciltiies.
What could Iran do quicker:
1) they could have bought one-to-few bombs as insurance while they get production going.
These would be vulnerable, last reserve and well kept secrets unless a demo is required, until they could make their own replacements; they might even work if they tried them.
2) they could have partially enriched uranium as starting materal for their enrichment pipeline.
Well, we know they do, because the russian power reactor was supposed to come with a few tons for power production. This can be enriched much faster than native ore to bomb levels, and you only need to enrich a little bit of it (and add some unenriched back into the bulk, so enrichment levels appear high, just not as high as they used to be). This gets you a few U-235 bombs earlier than full processing, with much fewer centrifuges.
3) they could have small operational reactors (which they do) doing lab batch production of Pu-239 through U-238 irradiation between IAEA visits. Gets you small amounts, but doable, maybe, without IAEA catching you. Maybe enough for two bombs, one to test, one to save. Eventually.
4) Busherhr reactior is by various accounts either 80% complete, or been up and running for 1-3 years.
If they left the exterior partly built, but the core is running without several hundred MW of electricity coming out, then it
is probably in plutonium breeding mode.
It takes a few months to cycle the Pu out, so they could have done one-few production batches, enough for several untested bombs to be assembled. If it is up and running for 1+ year.
PS: 5) Iran built a heavy water production facility, if they successfully built a hidden small heavy water reactor burning unenriched or low enriched uranium, then they could have been doing small scale Pu production for a few years. Big If.
The last option is the worst-case scenario.
If Israel or US has half-decent human or technical intelligence they know whether Bushehr is running, and someone within the government still knows what that could do, I think. At least over in Israel.
Israel is getting very antsy about this whole thing.
I'm thinking > 50% odds of a large airstrike in late April or early May this year.
It will be telegraphed, but "we" collectively will not believe they're actually going to do it, 'cause it is "completely nuts".
Either way Iran will be a nuclear power by 2015 and quite possibly much earlier.
They may become a very irate nuclear power, or merely just a paranoid one. Depends.
PS: argh, double post. Bad blogger...
IAEA has Bushehr-1 connecting to the grid in October 2006
If they are really planning to hook-up by Oct, then the fuel is either being delivered no later than, er, now; or, it is already there. News reports conflict about whether the fuel of enriched uranium was shipped or held up last year. Which is the case is very important for Iran's status.
If I were an Iranian engineer, I would have no-load runs several months before planning to go on the grid.
If I were an Iranian weapons designer I would do short burns and reprocess the blankets in those months, which means Iran could have started extracting Pu sometime between late 2005 and Real Soon Now.
If I were a Russian engineer I would go home now.
This is how to make scientific inferences
Money Magazine ranks the Top 50 jobs
College Professor comes second, right after software engineer.
So we infer that professors of software engineering are the happiest people of all?
Or is it professors who do engineering of software?
Or software engineers who profess?
'course Physical Scientists is way down at #16... one above the engineers and two above the curriculum developers.
Now I am confused. What if you're a physicist PhD who is a professor of software engineering who is developing a curriculum?
Is there really a separate profession of curriculum developers?
Management Analysts are ranked below Physicians, and, man, their mean salary sucks.
Fortunately Mental Health Counselor beats out Lawyer but Lawyers are ranked above Biologists?! and Environmental Scientists? Must be a salary weighing.
At least Registered Nurses are ranked above School Administrators.
Most growth is predicted for Physical Therapist Assistants but CSIs and Hydrologists are way up there too
Astronomers are pretty far down there in the big listing, low growth prospects but interesting mean salary. Money Magazine forecasts 79 new jobs in US Astronomy in the next decade.
I suspect they are badly miscounting - they must be not counting NASA scientists, and probably miss US off-shore facilities, there is likely to be steady state in university astronomer, growth in observatory personnel, and shrinkage in NASA positions.
They forecast a decrease in demand for Mathematicians, 33 jobs to be lost, along with Computer-Controlled Tool Operators (metal and plastic [but not wood?]), Fire Inspectors and Semiconductor Processors (I thought that was a thing, not a person, and that there was growth potential there...)
Hm, what to do with all those extra mathematicians, lets think...
Tangled Bank Tours Seattle
Never been to Seattle, need to fix that Real Soon Now...
I hear some people like it so much that they just up and leave for there given the slightest (or most excellent) opportunity.
Tuesday, April 11, 2006
Time Tree of Life
a database of taxonomic divergence times, primarily from DNA sequencing and fitting to best estimated divergence times,
but with geological timscale bounds included (which potentially introduces interesting asymmetries in the error estimates, but that is for another time).
The taxa comparison is endlessly fascinating, not all pairs work, but it is good to know that 100 Myrs separate us from Cats and Dogs both
Fun site, evolutionary genomics,
including theWest Indian amphibian and reptile database.
The Last 750 Million Years...
Another handy web site for intro classes: Berkeley does plate tectonics, backwards, forwards and in pieces.
My favourite bit is the Indian subcontinent racing across the Pacific. SPLAT.
Strangely, this is best viewed on a computer with a crap web connection. Too fast nowadays. Needs to be reanimated.
Shadow Illusions: Goethe's Revenge
A and B are the same shade of gray
Really, they are. I downloaded and checked the pixel values way back when.
Found this some years ago when explaining optics to an intro Honours class.
Edward Adelson at MIT has some more interesting optical perception illusions.
Some other ones: Green/Pink X
Monday, April 10, 2006
One Day I Will Rule the World - no surprise there
Imminence of the Eschaton: Google Our Future
it is not being considered as an option;
it has been considered as an option and been rejected;
it has been considered as an option and accepted...
End of discussion.
Oh, and saying that something is "completely nuts" is orthogonal to answering whether it is planned, intended or will happen...
it is an opinion about the advisability of an action, not an answer as to whether the action is to happen.
Jack the Lad has quite a way with language.
PS: ok, paranoia is a diverting sideline, and Krugman (behind the NYT wall) has a take on it this morning.
Seriously: get worried if two or more of the following occur
1-2 more aircraft carriers deploy to the "west Pacific" without a matching carrier returning to harbour
several 2-4 star generals quietly resign to spend time with their families
Whiteman AFB goes into a news blackout
Friday, April 07, 2006
Terrestrial Planet Finder - A,B.C... "c" first
High Contrast Imaging Testbed results from JPL (Trauger, 2004).
From Stapelfeldt's presentation at the 2005 Aspen workshop.
The Terrestrial Planet Finder
Two missions were proposed, TPF-c and TPF-i, I'll briefly discuss the former here.
The Terrestrial Planet Finder-coronograph was a visible light mission, intended to do direct imaging of nearby extrasolar terrestrial planets in visible light.
The essential difficulty in doing this is not that the planet is very faint, it is quite faint but not impossibly so, rather the problem is contrast.
An Earth-like planet a few light years away is very close to its parent star (less than 1" away on the sky for plausible orbits within the "habitable zone") and the reflected light of the planet is approximately a billion times fainter than the light of the star.
So, to see the planet, you must block out the light of the star - this is for two reasons, one is that an exposure deep enough to image the planet would lead to detector burn out from the star light, crudely speaking; and, the diffracted light from the star spreads out, swamping the light from the planet. This is unavoidable for any physical optical system.
You would think that just putting a mask over the star would block the light, but the diffraction of light around the mask will, in general, again swamp the light from any planet.
Fortunately, there are clever ways around that - you can't completely get around the problem of diffraction, but you can do some trade-offs: essentially, if you put in a funky shape "mask" across the telescope beam, you can change the shape of the diffracted light - the simplest pattern is the circular Airy disc, in general the diffraction pattern is the 2-D Fourier transform of the mask, for those of you who think in Fourier space...
In particular, you can choose a finite region within the image plane, where very little light is diffracted, almost none at all, at the price of having more diffraction elsewhere, but you just throw away that part of the image and search the dark patch away from the central bright spike. Then you rotate the telescope (or mask) and map out an annulus around the star.
Problem solved. (see for an early implementation of such masks)
And, as proof of concept that this is doable to the sensitivity level required, HCIT at JPL has shown billion-to-one contrast imaging, of monochromatic laser light in vacuum in the lab.
Rest is engineering (well, not quite, the edges of the mask need to be smooth at the atomic level, so nano-fabing is required, rather amusingly the blocked out mask areas need to be quite thick since a one-part-in-billion leak will ruin the image, there are issues of alignment and centering, the optical path has to be completely clean, and there may be some quantum optical issues, eg different polarization models may reach different levels of cancellations because of edge effects, where the electrical field of the photon interacts differently with the mask edge depending on whether it is parallel or orhogonal to the edge).
And then they were shut down and "indefinitely deferred".
It was a very ambitious mission, large mirror (and funky shape because no current launcher has a payload fairing with large enough a diameter to hold a large enough a mirror), and lots of tech to be developed.
But, it was exciting, doable, and likely to produce breakthroughs.
The engineering teams are dispersed, no new funding in the pipeline and the supporting science defunded with no calls for proposals in the pipeline.
So, what now.
Well. We could put it on the Moon. Heh.
Just kidding. Well, no, actually, not really. Moon is good.
There are new technologies on the horizon which may enable a smaller scope mission which will do something, particularly if results from the Kepler planet finder are promising; and of course the Europeans are turtling along in the inimatable way Darwin - Darwin as proposed is an interferometer, analogous to TPF-i.
More on those later.
There are also new high contrast imaging technologies some of which look rather interesting (like PIAA). We'll discuss those next.
Prospects are a bit depressing right now, but this too shall pass. Its funny, but it always seems to work out in the end, mostly.
iPod iChing - meta questions
So, iPod, do you answer questions of fact faithfully?
Whoosh. Randomizer goes whoosh...
- The Covering: Dein is Mein Ganzes Herz - Three Tenors
- The Crossing: La fille aux cheveux de lin - Claudio Arrau
- The Crown: Patti Broddgöltur - Thorbjorn Egner
- The Root: The Wheels on the Bus - Twin Sisters
- The Past: The Boy Done Good - Billy Bragg
- The Future: Peter & Wolf: Introduction - Prokviev
- The Questioner: Do Nothing - Specials
- The House: Staring at the Rude Boys - The Ruts
- The Inside: Fantaisie de Concert II - Perlman
- The Outcome: III Romance = Mozart
#11 is Savez-Vous Planter Les Choux - Sien Diels (huh?!) and #12 is Kátt er í hverjum bæ - Gáttaþefur (that's a cheerful christmas song).
Hmm. Tricky. I think I'm being scolded... and The House has Attitude! The Crown is the song of the porcupine...
The Future - hm, a lesson that ends well?
The Covering sounds like a "yes"; but who is the girl with the flax hair in the Crossing?
The Past: The boy done good, the girl done better,
The seasons turn and we're still together,
The sky is still blue and tomorrow is another day
I am not enough of a classicist to interpret The Outcome, seems kinda light hearted.
As always, the Key as explained by Sean
See him walk along this lonely street
Trying to find, find a future
New pair of shoes are on my feet
Cause fashion is my only culture
Nothing ever change (x2)
People say to me just be yourself
It makes no sense to fallow fashion
How could I be anybody else
I don't try I've got no reasons
Nothing ever change (x2)
I'm just living in a life without meaning
I walk and walk - do nothing
I'm just living in a life without feeling
I talk and talk - say nothing
I walk along this same lonely street
Still trying to find, find a reason
This man comes and smacks me in the teeth
I don't complain it's not my conscious
Nothing ever change (x2)
I'm just living in a life without meaning
I walk I walk - do nothing
I'm living in a life without thinking
I talk I talk - say nothing
Thursday, April 06, 2006
gravitational lensing - iSight geeks
Matt Turk has written a hack to illustrate gravtiational lensing with video input from iSight through a Mac. Just singular isothermal sphere lens, hack it yourself for other geometries, eh?
see here for lensing project page
and for powers of four blog entry
I will note that the possibilities here are endless, for people wanting realistic multiple magnified images...
Adventures in Academia - the lengths to which students will go...
So here I am, droning along in class: blah, blah swing amplification blah blah m=2 instability blah blah Lindblad blah blah corotation resonance blah blah
when, suddenly, subliminal parental instincts kick in, out of the corner of my eye I see the dreaded upwardly pointing sharp pencil moving Argh! No!
Too late, one of my grad students has very elegantly done a cheek piercing, in class... much hilarity and several cc of venal blood follow.
Fortunately, residual parental instincts continue flowing, and I get out a (clean) kleenex (snot from one year olds, dried over 12 hours doesn't count, does it?). Blood is mopped up and measures taken.
Back to the existence of the inner Lindblad resonance in barred spiral galaxies.
Good news is: all the students are now awake, and, The Wife is Right - those pointy pencils are a Real Hazard. Big Kid take note please.
Wednesday, April 05, 2006
what was that about transition fossils...?
The Fish that crawled out of the water...
Nature reports a spectacular "transition" fossil, of a large fish showing partial adaptation for living on land.
And so it goes...
Florida edu goes "Old Europe"
Florida high school students need to declare major
"TALLAHASSEE, Fla., March 25 (AP) — The Florida House passed a bill on Thursday that would make the state the first to require high school students to declare a major, just as college students do."
This is very much the "European" style for high school - you start specialising around 16 +/- and are better prepared for university, at least in theory, but narrower and some options are already restricted or precluded.
I'm ambivalent. I went through such a system, worked for me, I pretty much knew what I wanted to do, but a lot of 15-16 year olds don't, or they discover they don't have the aptitude or drive to do what they thought, and the current US system makes browsing and switching much easier all through to ~ 3rd year of university. At the expense of a relatively broad but generally more shallow education through BA/BSc
So, this is good for people who know what they want and stick with it, not so good for the rest.
Unless you think forcing people to make a decision is an inherent good, which it can be.
Protoplanets around Pulsars?
This is interesting...
Deepto Chakrabarty et al have Spitzer observations showing a debris disk around a young pulsar consistent with a protoplanetary fall-back disk post-supernova. (Damn, I wish I'd been on that SSU...)
Been speculated about for decades, nice to see; guess we have to take timing anomalies in young pulsars seriously now.
But, I don't think it is directly relevant to either of the known pulsar planet systems PSR 1257+12 or PSR1620-26, I could be wrong, but three planet formation mechanisms just for pulsar systems. Ouch.