Poor Photons

Last night, I found myself up at the observatory again. Surprisingly it was not a Dark and Stormy Night, but there were a few clouds that kept us from opening for some time.
Personally, I find it somewhat of a downer that these photons originated in a star mumbledy-mumbledy brazillion miles away, flew through the uncharted depths of space past wonders unknown by human minds, avoided vast interstellar dust clouds and other celestial obstructions, and traveled on a path destined to intersect the imaging system of a particular telescope on a particular mountain on the third planet of a rather ordinary, uninteresting star in the spiral arm of one of billions of galaxies…only to be intercepted at the very last possible moment by a wayward floating blob of water vapor a few hundred feet above the telescope.
The final result of their mumbledy-mumbledy brazillion mile tour of the universe was not, unfortunately, to be detected by advanced equipment, analyzed by up-and-coming scientists, and hopefully used to allow said scientists to better understand the universe. Rather, the result was that a particular blob of floating water vapor was heated by some infinitesimal fraction of a degree while the scientists below shake their fists and curse the clouds.
Truly, a rather pedestrian end to a photon that has traveled so far.

Doing Math for Fun and Science

The girlfriend of one of my fellow physics students works on the Lunar Reconnaissance Orbiter project.
Tonight as a bunch of us physics folks were sitting around my apartment chatting (the girlfriend was up in the Phoenix area), my friend noticed her status message on Skype posed a practical question which I paraphrase as, “If a spacecraft 20km away from the LRO vents ~100g of hydrazine, what’s the probability of hydrazine impacting the LRO’s optical elements? You have 20 minutes.”
Taking this is as a challenge, we started calculating the answer. We knew very little details, so we made some assumptions: the hydrazine is in a spherically-symmetric expanding shell, both spacecraft are stationary relative to each other, and gravity is not a factor. In a few minutes we came up with a quick, dirty, back-of-the-envelope calculation that indicated that it would be very unlikely for any hydrazine to contact the optics and, if any did, it would be a very small amount (on the order of a few molecules).
My friend relayed our calculations and results to his girlfriend, who was surprised: she didn’t actually expect anyone to bother working stuff out. After a short while, she informed us that our calculations had been passed upstream to NASA for their consideration.
Very cool.
Of course, our calculations were almost certainly unrealistic. Even so, they provide a starting point.
Yes, physics students actually do this sort of thing in their spare time.


I’m sure I’m now on some sort of government watchlist.
Why? Just now, I have several windows open in Firefox, each with several tabs.
Among the various tabs open, one had the contact information for a local pizza parlor, another had the .223 page of Ammoman, a third had the Wikipedia article about plutonium, another about various radiation-emitting nuclear reactor accidents that have occurred, one showed the page for the D-Zero accelerator project from Fermilab, and another displayed the university’s physics department website.
I’m not entirely sure what terrible, nefarious plots the feds might think I’m up to, but they’re all true MUWHAHAHAHA! there is absolutely no truth involved in any of them. I just happened to be doing a bit of research (Fermilab, physics department), being distracted and reading about plutonium and reactor accidents (just for the heck of it), was looking for ammo deals, and was hungry. Really. I swear.

Long Shot

Anyone have any good advice for a newly-minted graduate with a B.S. in Physics and a minor in math?
After getting out of the army a few years back, I thought it’d be a good idea to finish up my bachelors degree, so I’ve spent the last few years cloistered in the Physics & Atmospheric Sciences building at the University of Arizona. Now, I’m in the home stretch: if everything goes to plan, I will graduate next spring and be married shortly thereafter.
Unfortunately, this brings up the big question, “What next?” Do I go into industry? If so, where? Doing what? Maybe work as a lab technician? Teach? At what level? Do I go on to graduate school? Where? For what ((Physics? Engineering? I really enjoy science, particularly space science (as opposed to, say, quantum mechanics), rockets, etc. and would like to stay involved in related fields. )) Should I pursue a Masters or shoot for the Doctorate?
My soon-to-be-wife is a high school math teacher in the Phoenix region. While she makes a decent salary, it’s insufficient for her to be a sugar mama. Fortunately the grad schools I’ve been looking at will cover my tuition and pay of a stipend (not much, but it’s enough to live on), and the VA will give me ~$600 or so per month plus some money for tuition and books for three years, so we should be reasonably set for money, so long as we’re smart about it.
In addition to actually doing scientific research, I enjoy teaching, and would very much like to be a university professor at some point. In nearly all cases I’ve looked at, this requires a Ph.D. and from what I’ve been able to find out, it’s generally better to get started on this sort of thing early. Alas, I seem to have a bit more generalized love of science than a focus on a specific topic, so finding the necessary focus needed for a doctoral program would be challenging.
It’s a bit of a long shot, but do any of you, the gentle reader, have any advice for a person such as myself? While comments are welcome, I’d really appreciate email, as it allows for me to respond more personally.

Fun at Work

While the Epic Intercubicle Nerf Battle from two weeks ago was fun, my boss just informed us of an upcoming, interesting project: aerial photography.
We need to come up with effective ways to take photos from a long pole, a kite, and a balloon. These contraptions are to be constructed and provided to high school students to do various observations around campus.
I never thought that IT work (( Hey, it helps pay the bills while I finish up my degree. )) would be this much fun.

Rocket Fail

According to the BBC, the recent rocket launched by the North Koreans failed to achive orbit. The BBC quotes the US military thusly:

In a statement on its website, the US Northern Command said North Korea launched a three-stage Taepodong-2 missile at 0230 GMT.
“Stage one of the missile fell into the Sea of Japan/East Sea. The remaining stages along with the payload itself landed in the Pacific Ocean.
“No object entered orbit and no debris fell on Japan.”

Heavens Above, a orbital object tracking database, confirms the failure.
Perhaps someone should inform the North Koreans?
Rocket science is some pretty demanding stuff. New rockets require a lot of careful design and testing, and failures are commonplace. That’s why you actually do the testing prior to launching valuable payloads. Even so, failures still occur, which is why launch insurance is a good idea.
It seems incredibly unlikely that the North Koreans would be able to independently develop a rocket and successfully put a satellite into orbit on their very first attempt. Not even the US or the former Soviet Union were able to do that without extensive testing, large numbers of rocket scientists, a lot of ICBMs, and huge amounts of funding.
Of course, the Korean state-run media would never admit such a failure. That’s one of the things I love about living in a free country: our failures, in addition to our successes, are widely reported and known (who doesn’t know about the Challenger or Columbia accidents?). We never claim to be perfect, and such failures are experiences that we learn from.
Maybe the North Koreans should prioritize their people’s basic needs (food, water, etc.) rather than wasting resources on space and nuclear programs, not to mention their massive military? It seems like they’ve got their priorities all wrong.

Useful Math Site

It’s been a while since I’ve written about science here.
Recently, I’ve had need to exchange rather complicated math formulas with someone via email.
Sending formulas like
[hat{x}hat{p},frac{hat{p}^2}{2m}]=[hat{x},hat{p}]frac{hat{p}^2}{2m}+ frac{hat{p}^2}{2m}[hat{x},hat{p}]
is difficult to do clearly via email, as there’s no real means of formatting one’s text with math markup.
Fortunately, there’s LaTeX, an excellent typesetting system that is the de facto standard for marking up documents containing math. I hear it’s also common in the publishing industry, but have no personal knowledge of that industry.
For a long message, it’s probably easier to create a LaTeX document and attach it to the email, but my messages are often less than a page, and that is a bit of a hassle. Sending the raw LaTeX markup via email would also be unsuitable. That assumes the other person (a) has the software installed to read it, and (b) the time to copy-paste the code into their program and render it.
Similar problems exist for computer programmers, and the pastebin service exists as a highly effective way of exchanging programming code with other users. Surely there’s a similar thing for math and science folks, right?
Turns out there is: the Mathbin site allows one to enter text marked up with LaTeX and display it to others without any installed software. Very handy.

Pet Peeve of the Day: Exponents

How often do you see people using the words “exponentially greater” to me “very much greater”?
Pretty often.
Of course, it’s almost always used incorrectly by the mainstream press and general public, and this irritates me greatly.
Just like how there’s a clear meaning for words like “clip” and “magazine” (and they don’t mean the same thing), there’s a very clear meaning in math and science for “exponent” and “exponential growth“, and they don’t mean “very fast”, “very large”, or anything of that nature.
Don’t get me wrong, for large exponents, exponential functions increase extremely rapidly. But one can also have negative exponents (resulting in “exponential decay”, which is used to model things like radioactive decay), or very small positive exponents which result in extremely slow growth and long e-folding times.
In short: unless one intends to describe the actual expoential growth or decay of a certain function, please refrain from describing very large things as being “exponentially greater” than some other reference point. It makes you look almost as tardful as using “decimated” (to reduce by one out of every ten) to mean “utterly destroyed.”