Search found 314 matches

by Shadowfish
Mon May 28, 2012 7:24 pm UTC
Forum: Mathematics
Topic: Writing a paper about Cellular Automata
Replies: 44
Views: 7317

Re: Writing a paper about Cellular Automata

It sounds like rudi has noticed that some subset of initial conditions yield reversible dynamics for some number of iterations , and that the evolution starting from these initial conditions can be reversed in a straightforward way. This leads to the questions: 1) Will the CA evolve from a reversibl...
by Shadowfish
Mon Mar 26, 2012 3:22 pm UTC
Forum: News & Articles
Topic: Obsession over grades is killing American Education
Replies: 188
Views: 22878

Re: Obsession over grades is killing American Education

I want to post this on reddit when I get home. Where should I link to?
by Shadowfish
Mon Mar 19, 2012 4:16 pm UTC
Forum: News & Articles
Topic: Fascinating, if chilling, look at NSA activity
Replies: 93
Views: 12195

Re: Fascinating, if chilling, look at NSA activity

I am grateful that the government is taking decisive action to protect America from the terrorists that hate our freedoms. We are at war with Terror. The enemy is all around us. Terrorists, drug lords, music pirates, and hackers are working night and day to eradicate our way of life, and it is imper...
by Shadowfish
Sun Mar 04, 2012 5:06 pm UTC
Forum: Movies and TV Shows
Topic: My Little Pony: Friendship is MAGIC!
Replies: 1371
Views: 303994

Re: My Little Pony: Friendship is MAGIC!

This made me so happy. Of course any solution that involves flying wouldn't occur to Fluttershy.
by Shadowfish
Wed Feb 22, 2012 4:16 pm UTC
Forum: Science
Topic: How can I get good at nanotech
Replies: 5
Views: 2662

Re: How can I get good at nanotech

Your adviser will expect you to be completely worthless and burdensome for the first two years or so. When you start being really useful, it's time to graduate. That's not to say you shouldn't start reading now, but don't expect to become competent on your own.
by Shadowfish
Mon Nov 14, 2011 3:47 pm UTC
Forum: Movies and TV Shows
Topic: My Little Pony: Friendship is MAGIC!
Replies: 1371
Views: 303994

Re: My Little Pony: Friendship is MAGIC!

The fleur-de-lis mark made me think of a single pony out there somewhere with that mark, with nopony else to talk to. (Alternatively, the population of Prance is uninteresting because, collectively, their only talent is being able to speak with one another.) I think the ponies in Prance spe...
by Shadowfish
Tue Aug 16, 2011 2:31 pm UTC
Forum: Movies and TV Shows
Topic: My Little Pony: Friendship is MAGIC!
Replies: 1371
Views: 303994

Re: My Little Pony: Friendship is MAGIC!

This. This is what being a brony is all about. Love and tolerate my good friends. Love and tolerate. Cultural note: "love and tolerate" originally meant "Don't flame trolls, they'll get bored and go away". Recall, the fandom started on 4chan, the world capitol of trolling and ha...
by Shadowfish
Mon Aug 15, 2011 2:11 pm UTC
Forum: Mathematics
Topic: Choosing an advisor
Replies: 4
Views: 1069

Re: Choosing an advisor

Also, talk to the current students and find out if they are happy or not, and why.
by Shadowfish
Mon Aug 15, 2011 1:36 am UTC
Forum: Mathematics
Topic: Choosing an advisor
Replies: 4
Views: 1069

Re: Choosing an advisor

I was lucky when applying to grad school. I was accepted by a large physics department that is well-known for being good in a subfield of physics which I enjoy, and which I had some experience with. After a semester of TAing, I randomly jumped into a research group without exploring all my options v...
by Shadowfish
Tue Jul 19, 2011 3:24 pm UTC
Forum: Mathematics
Topic: Chaos pendulum
Replies: 19
Views: 3910

Re: Chaos pendulum

Side comment about the "no closed form solution" thing: I know that no one in this thread has actually said this, but a lot of people have the idea that chaotic systems never have a closed form solution. The two ideas are not really related. Most chaotic systems have no closed form solutio...
by Shadowfish
Wed May 04, 2011 1:19 pm UTC
Forum: Science
Topic: Electrostatic Discharge
Replies: 7
Views: 1166

Re: Electrostatic Discharge

You should see a doctor about that.
by Shadowfish
Thu Apr 28, 2011 4:08 pm UTC
Forum: Science
Topic: Nonlinear Schrodinger Equation
Replies: 7
Views: 1557

Re: Nonlinear Schrodinger Equation

Hey all. I'm reading about the derivation of the NLSE ( http://aflb.ensmp.fr/AFLB-303/aflb303m376.pdf ) and while I understand the math, the physical meaning of the equation is hard for me to grasp. As I understand it: a particle is represented/formulated as a complex-valued function. If you take t...
by Shadowfish
Wed Feb 23, 2011 6:39 pm UTC
Forum: News & Articles
Topic: "Nutjob Bills in the Montana Legislature"
Replies: 124
Views: 9791

Re: "Nutjob Bills in the Montana Legislature"

18. Declare that global warming is good. (House Bill 549)


Why won't they consider my bill which declare that maple syrup is a room temperature superconductor?
by Shadowfish
Wed Feb 16, 2011 6:39 pm UTC
Forum: News & Articles
Topic: Riots in Egypt
Replies: 380
Views: 33384

Re: Riots in Egypt

That's a horrifyingly tasteless article. What does her sex life have to do with anything? Or the repeated references to how attractive she is? That is not at all appropriate.
by Shadowfish
Mon Sep 20, 2010 5:00 am UTC
Forum: Science
Topic: DeBroglie Wavelength and relative motion
Replies: 8
Views: 1796

Re: DeBroglie Wavelength and relative motion

I figured there was a pretty good chance that Mavrisa knew trig but not that much complex stuff, so I said cosine instead of exp(i ...). There's no reason to bring in complex exponentials if you don't have to. You do not need to talk about squaring the magnitude of the wave function here. What I sai...
by Shadowfish
Sun Sep 19, 2010 10:30 pm UTC
Forum: Science
Topic: DeBroglie Wavelength and relative motion
Replies: 8
Views: 1796

Re: DeBroglie Wavelength and relative motion

Marvisa wrote: Then I thought, well wouldn't two observers travelling at different speeds observe different results from the same experiment (say, one plotting the interference pattern of a beam of electrons fired through two slits)? Relativistically, yes. Classically, no. (Here i assume you mean t...
by Shadowfish
Sun Sep 19, 2010 8:57 pm UTC
Forum: Science
Topic: DeBroglie Wavelength and relative motion
Replies: 8
Views: 1796

Re: DeBroglie Wavelength and relative motion

This is way simpler than Charlie! is making it sound, I think. The two relevant formulas are Frequency=energy/h, or f=e/h Wavelength=h/momentum, or lambda=h/p Together, these two equations give you the "phase" of the wave at a given point in space and time. The meaning of phase is that a w...
by Shadowfish
Sun Aug 29, 2010 4:52 pm UTC
Forum: Science
Topic: Advice on career choice
Replies: 21
Views: 2522

Re: Advice on career choice

At doogly's link above, all the physicists with BS's ended up either in engineering positions or as "scientists" doing what sounds like engineering. While I'm sure that BS Physics grads have more diverse careers, it's probably due more to necessity than versatility. In a pinch, most engin...
by Shadowfish
Sun Aug 29, 2010 2:24 am UTC
Forum: Science
Topic: Advice on career choice
Replies: 21
Views: 2522

Re: Advice on career choice

I think I understand this now: it doesn't matter too much what your undergrad is in, it's more the skills you learn in getting that degree that matter. People are prized for their analytically thinking in certain fields, and they can pick up the practical knowledge pretty easily once they have that...
by Shadowfish
Tue Jul 06, 2010 4:32 pm UTC
Forum: News & Articles
Topic: The Rational Optimist
Replies: 28
Views: 3411

Re: The Rational Optimist

I'm having trouble figuring out how this could possibly be true: The poorest 25% of Britons today are richer — have higher incomes, after taking inflation into account — than the richest 25% of Britons in 1961. Did the richest 25% of Britons in 1961 even have jobs? Wasn't not having a job one of th...
by Shadowfish
Tue Jul 06, 2010 2:28 pm UTC
Forum: News & Articles
Topic: The Rational Optimist
Replies: 28
Views: 3411

Re: The Rational Optimist

I'm having trouble figuring out how this could possibly be true:
The poorest 25% of Britons today are richer — have higher incomes, after taking inflation into account — than the richest 25% of Britons in 1961.
by Shadowfish
Mon May 10, 2010 7:47 pm UTC
Forum: News & Articles
Topic: New US Supreme Court Justice Nominated
Replies: 37
Views: 3748

Re: New US Supreme Court Justice Nominated

Pardon my newbishness, but what does "merits of the case' mean in this context? Does it refer to the practical implications that a ruling in favor of one side would have? Does it refer to the strength of the legal arguments which a side uses? I would think that evaluating the merits of a case r...
by Shadowfish
Mon May 10, 2010 5:47 pm UTC
Forum: News & Articles
Topic: New US Supreme Court Justice Nominated
Replies: 37
Views: 3748

Re: New US Supreme Court Justice Nominated

Ah, I see your point better now. I also see how it is problem that her philosophy is not clear.
by Shadowfish
Mon May 10, 2010 4:53 pm UTC
Forum: News & Articles
Topic: New US Supreme Court Justice Nominated
Replies: 37
Views: 3748

Re: New US Supreme Court Justice Nominated

It seems to me that the supreme court deals with more academic questions than real-world questions. They interpret the constitution in cases where the interpretation is not obvious. These are decisions about how whole classes of future court cases should be decided, rather than how to deal with one ...
by Shadowfish
Fri Apr 23, 2010 11:38 pm UTC
Forum: Science
Topic: Blackbody Radiation and Wierd Thermodynamics
Replies: 12
Views: 1546

Re: Blackbody Radiation and Wierd Thermodynamics

I'm not sure if this is reasonable to look at photovoltaics cells as heat engines or not. If it is reasonable to consider them heat engines, the they could not possibly do better than the Carnot efficiency, 1-/frac{T_{cold}}{T_{hot}} The hot reservoir is the sun, with a temperature of about 6000K, a...
by Shadowfish
Fri Feb 19, 2010 12:14 am UTC
Forum: Science
Topic: Too many scientists?
Replies: 79
Views: 10512

Re: Too many scientists?

Are all theorists the same as far as industry is concerned?
by Shadowfish
Thu Feb 18, 2010 11:09 pm UTC
Forum: Science
Topic: Too many scientists?
Replies: 79
Views: 10512

Re: Too many scientists?

If you just want to do physics for a few more years and then move into some other career, consider going for a masters. But a phd can be a great experience- if you go in aware that you are putting off starting a career and establishing yourself to learn. Different areas of physics have more industr...
by Shadowfish
Thu Feb 18, 2010 8:46 pm UTC
Forum: Science
Topic: Too many scientists?
Replies: 79
Views: 10512

Re: Too many scientists?

So is there any point in going to grad school in physics if you are pretty sure that you are not in the small fraction of people who will "make it" to professor? (I'm smart, but I have not delusions of being in the top .1%) How's the industrial physics market? Are you just pricing yourself...
by Shadowfish
Wed Feb 17, 2010 7:50 pm UTC
Forum: Science
Topic: Too many scientists?
Replies: 79
Views: 10512

Re: Too many scientists?

A postdoc's salary is enough to have a home for one person, but it is difficult to support a family on it, and you could very will be doing postdocs into your mid to late 30s. Further, you won't move across the country, but the world on postdocs. And finally, if staying in a geographical area is im...
by Shadowfish
Wed Feb 17, 2010 5:00 pm UTC
Forum: Science
Topic: Too many scientists?
Replies: 79
Views: 10512

Re: Too many scientists?

I'm planning to go to physics grad school, and so this topic is important to me. I'm not so worried about the money, since a postdoc's salary is enough to have a home and not starve. I'm worried that I won't be able to get a permanent job. Moving across the country every two years for a different po...
by Shadowfish
Mon Feb 01, 2010 8:22 pm UTC
Forum: Mathematics
Topic: Partition function issues
Replies: 6
Views: 938

Re: Partition function issues

I'm saying that there is no such thing as p_theta. In cylindrical coordinates, every position vector is r=r*rhat+z*zhat. This says go a distance r in the appropriate direction in the xy plane and then go up a distance z. That will locate any point. The time when you use thetahat is when you are spec...
by Shadowfish
Mon Feb 01, 2010 4:03 pm UTC
Forum: Mathematics
Topic: Partition function issues
Replies: 6
Views: 938

Re: Partition function issues

Blacksails, here is one problem: p is just a general vector: \vec{p}=p_r \vec{r} + p_{\theta} \vec{\theta} + p_z \vec{z} This is not true. \vec{p}=p_r \hat{r} + p_z \hat{z} \hat{r} points to every point in the xy plane, because \hat{r} depends on position. Edit: Also, are you integrating p over all ...
by Shadowfish
Sat Jan 30, 2010 3:57 am UTC
Forum: Science
Topic: public misconceptions
Replies: 1073
Views: 137923

Re: public misconceptions

Another one that annoys me a little:

"Why is it that you can build nuclear weapons, but you can't cure the common cold?"
by Shadowfish
Thu Jan 28, 2010 1:17 am UTC
Forum: Science
Topic: public misconceptions
Replies: 1073
Views: 137923

Re: public misconceptions

Ok, I'm actually quite appalled that this thread is 31 posts long this one hasn't been mentioned yet: "Science is boring." Seriously, does no one else have a problem with this? Many of the people I've encountered this view from are not stupid - but they have this stereotype of science as ...
by Shadowfish
Wed Jan 27, 2010 5:01 am UTC
Forum: Science
Topic: public misconceptions
Replies: 1073
Views: 137923

Re: public misconceptions

Newton's third law describes international relations, the second law of thermodynamics describes the degradation morality in society, and wave function collapse is magic that makes everything you think true.
by Shadowfish
Tue Jan 26, 2010 3:36 am UTC
Forum: Mathematics
Topic: Poisson equation
Replies: 10
Views: 706

Re: Poisson equation

Edited for wrongness.
by Shadowfish
Tue Jan 26, 2010 2:50 am UTC
Forum: Mathematics
Topic: Poisson equation
Replies: 10
Views: 706

Re: Poisson equation

The Green's function is proportional to 1/r, so you will find that the the integral diverges. I don't think there is a solution to your problem.
by Shadowfish
Mon Jan 25, 2010 5:20 pm UTC
Forum: Mathematics
Topic: Double Majoring Physics/Math
Replies: 23
Views: 6278

Re: Double Majoring Physics/Math

At my school, the required classes for a physics major get you to 2 classes shy of a math minor. I ended up with a math minor without planning to get one. I know of two physics/math double majors that finished in 4 years(they were pretty smart, and spent a lot of time doing homework). So, yeah, ther...
by Shadowfish
Sat Jan 16, 2010 12:32 am UTC
Forum: General
Topic: Making friends and all that jazz.
Replies: 13
Views: 1555

Re: Making friends and all that jazz.

That's correct, I'm a biochemistry-esque person. Not totally clear yet. I did send around a giant wad of emails asking professors about their research and if I could perhaps get involved with it last year (in hopes that I could do a yearlong research project for credit, since that sort of thing hap...
by Shadowfish
Fri Jan 15, 2010 9:50 pm UTC
Forum: General
Topic: Making friends and all that jazz.
Replies: 13
Views: 1555

Re: Making friends and all that jazz.

The second problem, related somewhat, is that I'm quickly realizing I need to develop relationships with my professors if I'm going to find research opportunities, get letters of recommendations, find internships/jobs relevant to my interests etc. Unfortunately, I don't often have enough trouble wi...

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