Wednesday, June 30, 2010

EM vs. Gravity:

Back in my first entry for the month of May, I mentioned a rather amazing experience I had with a pair of ridiculously strong magnets. I haven't mentioned it before, but those magnets ended up in Dr. Takamiya's office over the summer, allowing me to experiment (ok, play) with them in my free time.

In case you were wondering how big these magnets are, I took some pictures today during lunch of me releasing one magnet from below the bookshelf the other one was sitting on.

That photo was a 1/60 second exposure with flash, which should give you some idea of how fast that magnet is moving: very. It took me over 20 tries to capture this particular photo; every other time the magnet either hadn't left my hand yet or was already stuck fast against the board.

Monday, June 28, 2010

Astronomical frontiers.

Not much to write today, I spent most of the day resting and recovering from my sunburn of yesterday. In lieu of words, I offer this lovely panorama from the summit of Mauna Kea:

Edit (3/13/18): I've remade this panorama in Hugin, but you can still see the original hand-made version by mousing over the image.

Assuming you can make out the telescopes, from left to right we have the United Kingdom Infrared Telescope (UKIRT), the Caltech Submillimeter Observatory (CSO), the James Clerk Maxwell Telescope (JCMT), the Submillimeter Array (SMA), Subaru, Keck I & II, NASA's Infrared Telescope Facility (IRTF), the Canada-France-Hawaiʻi Telescope (CFHT), and finally Gemini North on the right. There are, in fact, only two telescopes on the summit that are not in this picture: the UH 2.2-meter telescope (directly behind me while taking this picture) and Hōkū Keʻa, the new UH 0.9-meter telescope that was finally installed this semester (and just achieved first light on the 17th, I heard. It's hidden behind UKIRT in this picture).

(If anyone is having trouble identifying the telescopes, I'd be happy to create a labeled version for you. Just let me know.)

Addendum: I just now realized that while there are technically no more telescopes on the summit of Mauna Kea than were mentioned in the preceding paragraph, there is one more close to the summit. That one would be the Very Large Baseline Array telescope, which is pictured two posts prior to this one, on the entry for June 24.

Sunday, June 27, 2010

Sand, surf, `n silverswords.

This morning, due to the excellent weather, I went to the beach for the first time since last August. I then discovered that I have a strong case of thalassophobia, which I just managed to hold off long enough to go swimming for 15 minutes, followed by happy tide-pooling for an hour and half afterwards.

I love the tide pools around here, so full of interesting little creatures! I saw so many fish of so many kinds today that I can't keep them all straight. I found a limpet nearly the size of a golf ball several feet above the water (and yes, it easily resisted my puny efforts to unseat it), lots of little snails (mostly of the Nerite family), and my personal favorite: hermit crabs!

Many moons ago, back in California, I used to keep hermit crabs as pets, and they never failed to amuse me with their antics (or amaze me with their Houdini-like ability to escape). Here, you can walk up to most any tide pool and see them skittering and climbing around in it. They use all different kinds of snail shells, often giving them a clownish and humorous appearance.

Anyway, I promised to write about my Mauna Kea trip last week, so here we go. I went out to see the silverswords (`āhinahina) last Saturday, and was fortunate enough to find one in bloom. Each rosette of a silversword may grow anywhere from 5 to 20 years before flowering, after which it dies, so I was quite thrilled to see one.

Argyroxiphium sandwicense in flower. (from the Greek, argyrion, silver, and xiphius, sword. And sandwicense from the name given to the Hawaiian islands by James Cook in the 1770's)

While bending over to get a closeup photo of the flowers, I made a startling discovery: silversword flowers smell really good!

You can clearly see that these plants are in the sunflower (and marigold) family, Asteraceae.
This was a startling discovery to me because I'd read a bit about silverswords before seeing them for the first time, and nowhere was it mentioned that the flowers had any noticeable scent. I couldn't place what the scent reminded me of at the time, but while writing this post I realized that it was remarkably similar to the scent of sunflowers, just a bit sweeter. It's a fairly strong scent too, as I discovered just by bending down to take a picture. I'd guess the strength of the smell is only a little less than that of a typical rose. I don't know how many times I'll ever have this opportunity again considering the rarity of flowering, so I'm quite glad I've been able to enjoy the fragrant odor of a silversword in blossom.

Friday, June 25, 2010

Thoughts on astrophotography.

Things haven't been too busy around here, but they have been happening. I've just been too lazy recently to write about them. Rather than write one big block post, I'll space it out over a few days. It's taken me this long to get around to writing about it, but Saturday I went on a summit tour to Mauna Kea, during which I decided to stick around for stargazing as well. That's 10 and a half hours above 9,000 feet, which can take a bit of a toll on your energy levels.

The summit tour was nice, although once again -- as it has been 4 out of 5 of the times I've gone -- there were some scattered clouds around the summit (strangely, the one time it wasn't cloudy is when I forgot my camera, although they assure me that such cloudy days are rare up there. Apparently I am a cloud magnet). We stopped at the Very Large Baseline Array telescope on the way up to the summit, which allowed me to get this great picture of the first-quarter moon over the telescope:

Moon over VLBA.
For comparison, this telescope is 82 feet (25 m) in diameter, nearly 10 stories tall when pointed straight up, and weighs over 200 tons (I had to cut off the base so you could see the moon easily).

Stargazing in the evening went well too, although the first-quarter moon washed out most of the Milky Way, so I couldn't get a picture of it. There were a lot of people there; two different school groups, a group of Women in Engineering, plus the usual assorted tourists. Probably close to a hundred for a good part of the night.

I spent some hands-on time with one of the larger Dobsonian-mounted Newtonian telescopes, observing Saturn, Mars, the Moon (blindingly bright!), the beautiful double star Albireo (two similar brightness stars, one yellow, one blue), and the tiny but iconic Ring Nebula in Lyra. As an astronomer, I feel it's important to do some visual observing once in a while. Most of the things I observe in the telescope I have already seen in photographs, often very good ones, perhaps even by the Hubble Space Telescope. Compared to those pictures, what I see in the telescope is somewhat akin to watching a High-Definition made-for-widescreen movie on a 5-inch black-and-white screen. And yet the visual experiences are what leave me overawed and grasping for words to describe, every time. I have a special fondness for Saturn, and have seen a good many amazing pictures from the Cassini space probe currently orbiting it, but the most immediate reactions I have to it are when I'm seeing it as a tiny dot that I can just make out the rings on, with Titan and perhaps another moon or two hanging off to the side in its gravitational embrace. A picture is worth a thousand words, so they say; but a good visual observation is worth a thousand pictures any day (or night) in my book.

(of course, sometimes pictures are all you can have, which is why I will continue to keep taking them for those who don't have the privilege of seeing these things for themselves)

Next time I'll post some pictures of silverswords in bloom, along with a surprising fact I learned about them on Saturday...

Friday, June 18, 2010

Happy busyness.

Just a quick note to say that today I found out I am essentially done with the line of work I've been pursuing for the last month. I showed Dr. Takamiya some of the before-and-after spectra plots I'd produced using my motley collection of scripts, and she was quite pleased with them. Quite. She got especially excited about the presence of two lines from sulfur in the resultant plot, saying they were very difficult to isolate from the veritable forest of hydroxide lines that surround them. She even suggested I save that particular pair for eventual publication as an example, which, suffice it to say, raised my spirits for the rest of the day.
So, being done with reducing the available data, I started work on a master list of all the spectra files I've been working with, to eventually include a picture of each galaxy we've been working on with the areas we were looking at marked and labeled. Much more basic accounting work than anything, and frankly not my preference, but 'tis such data accounting that makes up most of the work in research: only when you've accounted for every data point can you draw your conclusions at the end.

Thursday, June 17, 2010

Busy happenings.

This week is quite busy for me, between working during the day and helping out with VBS in the evenings. Well, except for last night, when I went to the Vis as the driver. Sure was an awesome night, but my attempts to photograph the galactic core were thwarted by my camera's battery running out of energy.

Anyway, between those things, I'm being kept on my toes, so you probably won't hear much from me for the remainder of the week.

Monday, June 14, 2010

Mind-blowing moments of the galactic kind.

I've been a little scatterbrained lately with having been up extremely late (or early!) several nights recently, with another two coming up. Tonight we're going observing at the Institute for Astronomy with the UH 2.2-meter 'scope again, and then Tuesday night I'm heading up to the Vis for stargazing. I went there last night as well as part of the University Astrophysics club, with the intent to use the imaging system since it was only one day past new moon. Unfortunately, the weather refused to cooperate, being partly cloudy for much of the night, especially in the early evening, and even downright drizzling on us for a bit (which necessitated scurrying around to cover up sensitive telescopes). However, near the end of the night the weather cleared up enough to let us collect some data on NGC6302, the "Bug Nebula".  I'm hoping to finally put together the data I've collected so far pretty soon and actually have some astrophotos for you to see. I might even work on that tonight...

Last night was also special because I really saw the core of the Milky Way for the first time, and it nearly blew my mind. While I have seen the core before, from California, I saw it from Mauna Kea for the first time last night, and it was awesome. My impression had always been that the band of the Milky Way was no thicker in the vicinity of the core than it was anywhere along its length, but with the clear skies of Mauna Kea I was able to see it looming over me, bulging out from either side. Dark dust and gas clouds were also silhouetted against the myriad stars of the galactic core more clearly than I've ever seen them before. I wanted to get a picture of it, but was afraid of bringing my camera out and having it get rained on. Certainly, though, it is very high on my list of priorities for next time I go back. I'm still itching to try out my birthday tripod for astrophotography!

Sunday, June 13, 2010

Experiments in sleep-deprived post-writing.

As I write this, it is 4 o`clock Saturday morning (Hawaiian Standard Time), and I have been observing for 10 and a half hours, and awake for a little over 19. Unlike Wednesday night (well, Thursday morning), when wind speeds in excess of 50 mph at the summit forced us to close up early, the weather tonight has been more amenable, with moderate seeing (hovering around 1 arcsecond, which is quite good for most observatories on Earth, but poor for Mauna Kea with its often 0.5 arcsecond seeing).

(Seeing is simply a measure of how well you can resolve two objects at the telescope. If you have seeing of one arcsecond, you can resolve two objects one arcsecond apart, assuming an optimally built and focused telescope [an arcsecond is 1/3600 of a degree of arc, a very small angular measurement].)

Observing can be pretty boring work. I expect to be here for nearly two more hours, which makes almost 11 and a half hours of observing in a row. [Edit: it turned out to be a little less than an hour and a half, I forgot twilight came so early in the summer] We're using the SNIFS camera on the UH 2.2-meter telescope, which has a lot of automation built-in that results in large portions of down time for us. The good part of this is that I will soon have more data to work with, because the data I've been analyzing has all come from SNIFS. With the scripts I've written, it is a simple matter to run the data through and catch it up to the rest of the data.

Writing posts while sleep-deprived to this extant is turning out to be harder than I anticipated, so I'm going to stop now and focus on staying awake. We have one more night scheduled for the current run, on Sunday, which I plan to be at. Due to a misunderstanding, the WFGS2 camera that we might have used did not have its dewar of liquid nitrogen refilled, so we'll be using SNIFS again (being a spectrometer, it does not have such a critical need to be kept cold). The upside, once again, is more data for me to work with!

Thursday, June 10, 2010

All-nighter news.

Things have been rather quiet lately so not much to say, I've just been working and catching up on my sleep. That is rather important, as I'm leaving for an all-night observing run tonight in less than an hour. It's not to the summit this time, just up to the Institute for Astronomy to use the University 1.88-meter scope remotely, but it's still pretty cool. I'm also planning to bring my computer and get some more work done (since I'm going to be there for almost 12 hours straight, might as well get something done while I'm there).

Sunday, June 6, 2010

Burning questions of a Saturday morning.

So there I was lying in bed this morning, still half-asleep, when I got to pondering the fact that I, like the atoms that compose me, am made up of 99.99% empty space. I then idly contemplated the fact that most of this mass was in the nuclei of my atoms, at which point I was seized by a burning desire to find out how much all the electrons in all the atoms of my body put together weighed.

I know that last I checked, I had a mass of approximately 60 kg (my weight is left as an exercise for the reader), and a little searching on the 'net produced a table with the percent-by-mass composition of an average person. Starting with the first entry in the list, I have around \(61.35\text{%}\cdot 60\ \text{kg} = 36.81\ \text{kg}\) of oxygen in me. That's 36,810 grams of oxygen. A mole of oxygen being 16.00 grams, that's almost exactly 2,300 moles of oxygen in me.

(A mole, in chemistry, is simply a very large number \(-\ 6.022\times10^{23}\), to be exact. The conversion between grams and moles is pretty easy; if you have an amount of a substance equal in grams to the atomic weight of one atom (or molecule) of that substance, you have one mole of that substance, i.e., \(6.022\times10^{23}\) atoms (or molecules) of the substance. Since the atomic weight of oxygen is 16.00 atomic mass units, one mole of oxygen is 16.00 grams of oxygen. One more of oxygen at \(0^\circ\)C and normal atmospheric pressure would occupy about 22.4 liters, or just under 6 gallons.)

Now, each oxygen atom comes with 8 electrons in tow, \(8\) electrons \(\times\) \(2,300\) moles \(\times\) \(6.022\times10^{23}=1.11\times10^{28}\) electrons. a very large number. (11.1 billion billion billion).

And that's just the first element on the list! (Although, by virtue of its nature, it is likely to provide the largest number of electrons.) Next up is carbon, which, at 22.83%, comprises 13.70 kg of me. Dividing by 12.00 grams per mole, and multiplying by 6 electrons to each carbon atom, we arrive at \(3.09\times10^{27}\) electrons from carbon, a factor of 10 less than from oxygen (not surprisingly).

Since the procedure is relatively boring, and quite simple, I will spare you further talk and simply list the amounts in the table below:

oxygen        36.81 kg  \(1.11\times10^{28}\) electrons
carbon        13.70 kg  \(3.09\times10^{27}\) electrons
hydrogen      6.00 kg   \(3.57\times10^{27}\) electrons
nitrogen      1.54 kg   \(4.64\times10^{26}\) electrons
calcium       0.86 kg   \(2.58\times10^{26}\) electrons
phosphorus    670 g     \(1.94\times10^{26}\) electrons
potassium     120 g     \(3.51\times10^{25}\) electrons
sulfur        120 g     \(3.61\times10^{25}\) electrons
sodium        84 g      \(2.42\times10^{25}\) electrons
chlorine      84 g      \(2.43\times10^{25}\) electrons
magnesium     18 g      \(5.35\times10^{24}\) electrons
iron          6.0 g     \(1.68\times10^{24}\) electrons
fluorine      2.4 g     \(6.85\times10^{23}\) electrons
zinc          1.8 g     \(5.00\times10^{23}\) electrons
silicon       0.60 g    \(1.80\times10^{23}\) electrons
rubidium      0.60 g    \(1.56\times10^{23}\) electrons
strontium     0.30 g    \(7.84\times10^{22}\) electrons
bromine       0.24 g    \(6.33\times10^{22}\) electrons
lead          0.12 g    \(2.86\times10^{22}\) electrons
copper        0.06 g    \(1.65\times10^{22}\) electrons
aluminum      60 mg     \(1.74\times10^{22}\) electrons
cadmium       60 mg     \(1.54\times10^{22}\) electrons
cerium        60 mg     \(1.50\times10^{22}\) electrons
barium        18 mg     \(4.42\times10^{21}\) electrons
iodine        18 mg     \(4.53\times10^{21}\) electrons
tin           18 mg     \(4.57\times10^{21}\) electrons
titanium      18 mg     \(4.98\times10^{21}\) electrons
boron         18 mg     \(5.01\times10^{21}\) electrons
nickel        12 mg     \(3.45\times10^{21}\) electrons
selenium      12 mg     \(3.11\times10^{21}\) electrons
chromium      12 mg     \(3.34\times10^{21}\) electrons
manganese     12 mg     \(3.29\times10^{21}\) electrons
arsenic       6.0 mg    \(1.59\times10^{21}\) electrons
lithium       6.0 mg    \(1.56\times10^{21}\) electrons
cesium        5.4 mg    \(1.35\times10^{21}\) electrons
mercury       5.4 mg    \(1.30\times10^{21}\) electrons
germanium     4.2 mg    \(1.11\times10^{21}\) electrons
molybdenum    4.2 mg    \(1.10\times10^{21}\) electrons
cobalt        2.4 mg    \(6.62\times10^{20}\) electrons
antimony      1.8 mg    \(4.54\times10^{20}\) electrons
silver        1.8 mg    \(4.72\times10^{20}\) electrons
niobium       1.2 mg    \(3.19\times10^{20}\) electrons
zirconium     0.60 mg   \(1.58\times10^{20}\) electrons
lanthanum     0.60 mg   \(1.48\times10^{20}\) electrons
gallium       0.60 mg   \(1.61\times10^{20}\) electrons
tellurium     0.60 mg   \(1.47\times10^{20}\) electrons
yttrium       0.54 mg   \(1.42\times10^{20}\) electrons
bismuth       0.42 mg   \(1.00\times10^{20}\) electrons
thallium      0.42 mg   \(1.00\times10^{20}\) electrons
indium        0.36 mg   \(9.25\times10^{19}\) electrons
gold          0.18 mg   \(4.35\times10^{19}\) electrons
scandium      0.18 mg   \(5.06\times10^{19}\) electrons
tantalum      0.18 mg   \(4.37\times10^{19}\) electrons
vanadium      0.12 mg   \(3.26\times10^{19}\) electrons
thorium       0.060 mg  \(1.40\times10^{19}\) electrons
uranium       60 μg     \(1.40\times10^{19}\) electrons
samarium      42 μg     \(1.04\times10^{19}\) electrons
beryllium     30 μg     \(8.02\times10^{18}\) electrons
tungsten      18 μg     \(4.36\times10^{18}\) electrons

(if you're wondering about the units, conveniently, 0.06 g = 60 mg and 0.06 mg = 60 μg)

If you add all those electrons up, you come up with a total of \(1.88\times10^{28}\) electrons. That's a lot of electrons -- 18.8 billion billion billion, to be exact. But how much mass do they have? And how much do they weigh?

Finding the mass is easy. The mass of an electron is \(9.11\times10^{-31}\) kg so \(1.88\times10^{28}\) of them together have a mass of 17.1 grams, which has a weight of approximately 1/25 of a pound.

Wow. All the electrons in my body make up a measly 0.0000029% of my mass. Everything else is concentrated in the nuclei of my atoms. Wild, huh?

Saturday, June 5, 2010

On the difference between desktops and laptops.

There is one essential difference between a laptop and a desktop: mobility. And there are two things that together make this freedom possible: a battery and a wireless card. Without a battery, you are very limited in going places and have no real need for a wireless connection, and without a wireless card you can go as you please but might as well be stuck within cable range of your router.

Having owned computers that were lacking in either one or the other, I have learned this very well.

(Sorry if you were looking for something deeper, that's all for today. Musings range the spectrum from profound to superficial)

Wednesday, June 2, 2010

Wonderful wireless Web-ing!

I feel like I've been talking about myself overmuch recently, but I can't resist mentioning that my replacement wireless card came in the mail today! I installed it this evening, and so far it works perfectly.
It turns out all those hours of playing with Legos came in handy: there are two little wires connecting the wireless card to the antenna in the frame, which connect using a snap-on and off interface. As I was snapping them on, I briefly wondered how much force would be required to break them, which was followed almost immediately by the discomfiting thought that it probably isn't much more than the force required to snap them on. Thankfully, everything went without a hitch, and I am now enjoying wireless freedom again.