Tuesday, October 30, 2012

The Veil Nebula

Today, instead of pictures of spiders and caves, I have a picture of the lovely celestial object known as the Veil Nebula. Now, I'll have to be more precise than that: you see, the Veil Nebula as a whole refers to a humongous supernova remnant about 1,470 light-years away in the constellation Cygnus, the Swan. This nebula is quite large: it can be traced for almost 3 degrees in the sky, making it 6 times wider than the full Moon (and about the width of the Andromeda galaxy), while covering 36 times the area. Because it is such a diffuse ball of gas spread over such a large area (nearly a hundred light-years), it is easiest to see around the edges.

There are a few places where those edges are thicker and easier to see, and it is one of those edges that I have for you to see today. This part is known as the Western Veil nebula, and is one of the two brightest portions of the nebula. Because the nebula is so tremendously huge on the sky compared to most objects, different parts of it have actually been assigned their own numbers in the New General Catalogue (NGC). This part is known as NGC 6960.

The Western Veil Nebula, NGC 6960, in Cynus. The bright star is an unrelated foreground star, 52 Cygni.
So in this picture, you can see part of the outer arc of the supernova remnant where it's a bit thicker than average. The original explosion site was to the right and slightly below this picture, and if you look closely to the right of the bright part of the nebula you can see very faint and wispy filaments of gas. The nebula looks sort of purple-ish to me; the blue light comes from doubly-ionized oxygen, and I suspect that the red light is your basic hydrogen-alpha.

Monday, October 29, 2012

Spiders and Spelunking Pictures

After exploring the uphill ("mauka") side of Kaumana Caves last week, I got a few pictures of the trip from my friend. Now, while I hate having my picture taken in any sort of “candid” form, or your standard “everyone stand together and say ‘cheese’!” moment, I do enjoy hamming it up for the camera on occasion. With that said, here are a few pictures of me in the caves:

“After hours of contemplation, I have concluded: this is, indeed, a rock.”
(I've got quite The Thinker vibe going on here, don't I?)

This is the entrance to a neat little side tunnel off the main tube that I'd like to explore sometime.

I really, really like this picture. This is the skylight that reminded me of Portal 2.

If you read the post title and are wondering where the spiders come in, wonder no more. It involves my first encounter with the Heteropoda venatoria, also known as the brown huntsman spider or (in Hawai‘i) the cane spider.

The story begins this Sunday, as I was riding home from church on my moped, when I thought I felt something move in my hair inside my helmet, which I had left on the moped seat outside during the service. Of course it happened while sitting at a red light, leaving me with a burning desire to get to the side of the road and get my helmet off as quickly as humanly possible. When I did, imagine my surprise at finding a cane spider with a good 3-inch leg-span running around frantically inside my helmet.

I'm a bit of an arachnophobe when it comes to spiders larger than a dime that move super fast, and according to Wikipedia cane spiders are “very easily alarmed” by humans, so I think it's safe to say that both of us were pretty much equally terrified. I dropped my helmet, and the spider ran out (and boy let me tell you, those suckers move fast).

At this point, I'm proud to say that my scientist instincts kicked in and my curiosity mastered the powerful urge to flee blindly in panic (especially when the spider ran right at my feet). Quickly whipping out my camera I was able to get the following two pictures of the spider before it ran off:

I'm not sure what it is about making first contact with Hawai‘i's creepy-crawlies in my hair (see: my first encounter with a centipede), but I'm really hoping this doesn't become a trend.

Saturday, October 27, 2012

Another Tsunami Warning

You may have heard from the news recently of a magnitude-7.7 earthquake off the coast of Canada that generated a tsunami warning for much of the Pacific. I'm doing fine as usual, safe two blocks beyond the evacuation zone, and as of 11 P.M. there hasn't been much activity beyond a few tiny swells. This tsunami isn't estimated to be very large (like the last two I lived through), but the thing that makes tsunamis  dangerous is that they're notoriously difficult to predict. They can wrap around islands and sometimes the most powerful wave can be on the opposite side of the island from the direction it came from.

Anyway, I'll let you know if anything major comes out of this one. The fact that tsunamis come about once a year but are generally not large enough to do too much damage tends to make one a bit nonchalant about them.

Tuesday, October 23, 2012

Kaumana Cave Crawling

Located a little ways beyond the outskirts of Hilo just off Kaumana Drive is Kaumana Caves County Park. The eponymous caves are actually the remains of a lave tube formed during the 1881 eruption of Mauna Loa that came within a few miles of wiping out Hilo. Lava tubes come about during an eruption when the surface of the flow cools and forms a crust beneath which lava continues to flow, eventually concentrating into channels that may eventually empty of lava and become hollow. Sometimes the roofs of these channels collapse in “breakdowns” (making “entrances” or “skylights”), places that you can potentially climb down and enter the tube. The Kaumana Caves County Park contains one such entrance at an elevation of about 1,000 feet with a handy flight of steps leading down to the lava tube floor. (There's a neat site here with some good pictures that explains many of the terms used in lava tubes.)

Anyway, the point of this post is that last Sunday I had the chance to explore the caves for myself for the first time, along with a co-worker who had never been before either. Upon descending the steps into the skylight in the park, we were immediately faced with a choice: left or right (since the skylight is in the middle of the tube, it continues both uphill and downhill on either side).

Entrance to the right side of the Kaumana Caves lava tube.
We chose to investigate the left-hand (uphill, or mauka) side, because I'd heard that it was a bit shorter than the right-hand side. So, not the side that I actually took a photo of. The entrance to the left side looks similar except that it appears to end in collapse a short way in. It doesn't, but it may not be immediately obvious.

Warning sign at the bottom of the steps.
While this isn't exactly what I would term a dangerous cave in the sense that you don't have to worry about slipping and falling dozens of feet onto stalagmites at the bottom of a pit, it is very definitely a cave left very much in its natural state. Unlike the more famous Thurston lava tube near Kīlauea which has a smooth floor and electric lights installed, the Kaumana lava tube has a much rougher floor in places due to collapse of the roof and has no artificial lights of any kind.

Surprisingly, I wasn't able to find much information about the cave online, other than that it was formed by the 1880 eruption of Mauna Loa which everyone agreed on. Various sites listed distance up to 22 miles long if it weren't for roof-collapses that blocked the tunnel; however, a site I found listing the world's longest lava tubes ranked the Kaumana lava tube at #63, at 1.365 miles in length.

(Interestingly, the top four longest lava tubes in the world are all on Hawai‘i island, and are all over 10 miles long. Emesine Cave, the fourth-longest at 12.89 miles, was also formed by the same 1880 eruption of Mauna Loa as Kaumana Caves, and is located further up the flank of the volcano. The longest one, called Kazumura Cave, is located about 20 miles south of Hilo, was formed about 500 years ago by an eruption from Kīlauea, and contains a whopping 40.7 miles of total length!)

Anyway, getting into the left entrance of the Kaumana Caves involves finding it first. It's not that hard to spot, but the lava tube mouth is somewhat obstructed by the roof collapse that formed the entrance that permits entering it in the first place, and it's not immediately obvious to the casual glance. Once inside, the view is spectacular. I'm finding myself at a loss for words to describe what it looks like. The rocks on the inside are so unlike anything I'd ever seen before that I had to keep telling myself that no, they weren't fake movie props from some Hollywood set. It's an excellent case of real life being stranger than someone could ever think up.

Once inside, I found myself surrounded by a fantastic menagerie of strange and fluid shapes. All about me were the cooled remains of once-molten, living rock now frozen into a bewildering variety of poses. The bizarre, colors, lumpy shapes, and uncharacteristically smooth surfaces were so far removed from my everyday perception of what rock is that my mind had a hard time recognizing the mysterious substance around me as mere stone. Light-reflecting minerals coated the walls and ceiling, throwing the light of my small headlamp back from a myriad facets like a multitude of tiny stars. Everywhere the colors red, black, and silver met my eye. It really was a surreal experience, a place unlike anywhere else I've ever been. They say a picture is worth a thousand words, and through the magic of the Internet I can simply show you a picture and stop fumbling for words.

View back to the cave mouth (the green in the center) from about 6 or 7 meters in.

The cave floor at this point was made up mostly of jumbled rock that had collapsed from the ceiling, and you can see the vivid red color present. This comes about because the rock cooled very rapidly, or so I've heard (anyone out there who can verify this?).

Present on the roof and walls of the cave was a mysterious silvery material that you can see in the picture as well. I don't know what this is, though I would suspect it's some kind of mineral that crystallized on the exterior of the rock as it cooled and hardened (from what I've read, it may be gypsum). It's incredibly beautiful, and reflects light in the dark cave environment like you wouldn't believe.

A picture showing the cave ceiling where some of the rock as fallen away, revealing more of the mysterious silver mineral behind it.
The lava tube also contains lots of lavacicles – which are similar to icicles, just with molten rock rather than water. They form as the lava level in the tube recedes, leaving a clear space near the top where lava can stick to the ceiling then freeze in place as it cools and drips down.

Lavacicles! Sorry about the blowout on the right there, this was my best picture of them.
Another shot of another part of the ceiling.
Once inside a little way from the entrance, the floor changed from jumbled ceiling-collapse to a slightly smoother surface made up of the last lava to flow through the tube, frozen in place in all its wrinkled glory. This type of surface is known (quaintly enough) as “cauliflower ʻaʻā.” Pure ʻaʻā generally doesn't exist in lava tubes, but this is sort of a transitional form between smooth, ropy pāhoehoe and sharp, angular ʻaʻā.

The last lava to flow through this tube, now frozen in time, makes up the floor of the cave for quite a while.
As the flow of lava from the vent cracks of Mauna Loa subsided, so did the amount of lava flowing through the tube. Eventually the last little bit didn't have enough pressure behind it to push it downhill, so it froze in place making up a rough but not unpleasant walking surface (just watch your step! Everything is moist in here).

I just want to take a moment to remark on how difficult it is to get good pictures in caves like this without enough light for the camera to be able to auto-focus. Seriously, it's really hard. You might think that the astrophotographer, who spends time taking pictures in low-light environments, might have been able to foresee this, but no. I do know to be better prepared for the future, however. I ended up not actually taking too many pictures, something I hope to remedy next time (since there was certainly no lack of things interesting enough to be photographed).

Along the side of the tube wall in places there was a sort of shelf or curb where the lava slowly cooled from the edges in as the inflow was slowing down. You can see it in the picture below:

At top you can see the cave wall, then the curb in the middle, and the cauliflower ʻaʻā floor at bottom.
One thing that helped remind us that we weren't that deep underground (all things considered) was the amount of tree roots growing down from the ceiling. There were quite a few of them in places.

Masses of tree roots hanging down over some roof-collapse rubble.
Another reminder was the presence of skylights at intervals:

Skylight in the tube. This scene looks like something you'd find in the early levels of Portal 2.
While near the skylight seen above, I found some interesting features in the floor. It looks like fossilized bits of tree bark and possibly fern leaves.

Fossilized organic material embedded in the lava making up the tube floor.
More organic material. Looks like tree bark, possibly from the abundant ʻōhiʻa lehua trees in the area.
Near the end of the cave system a breakdown in the tube let us scramble up the collapsed rock and emerge from its associated skylight. We felt that a nice walk overground was in order to get back to the car, so set off along what appeared to be a trail.

I should mention that we emerged in the middle of an ʻōhiʻa lehua forest with a lot of undergrowth of a particular fern-like plant that I didn't recognize, with no sign of civilization other than the noise of the occasional passing vehicle on Kaumana Drive. Looking on a map, I see that the exit point was no further than 300 meters (1,000 feet) from where we entered, but it felt like the middle of nowhere due to all the trees (it was also on the opposite side of the highway from where we started). The trail we were following very quickly began to appear and disappear as trails in forests are wont to due, so I had to pull out the GPS on my phone to make sure we were actually making our way back to the car.

Also very prominent on our minds was the fear of suddenly falling through a well-covered skylight hidden in the undergrowth. It wasn't always easy to determine what was solid rock footing, what was dirt or organic material, and what was leaves growing over a depression in the ground. ʻŌhiʻa trees don't really make good sticks for prodding the ground in front of you to see if it is in fact ground and not a gaping hole, so we took it slowly and carefully. Thankfully, between GPS and my good sense of direction we made it back to the parking lot where we'd parked without incident (beyond a few mosquito bites), although I'm pretty sure I was blazing my own trail for at least part of the time.

All that climbing around took a bit longer than we'd expected, and after forcing our way through the thick undergrowth we were both pretty tired, so we decided to put off exploring the makai (right-hand) side of the tube until next week, when we plan to return making use of what we learned from this expedition. (For instance, I was surprised at how warm it was in the caves, being used to thinking of caves as cool places. It was cooler than the outside air, yes, but not much, and also very humid so I worked up quite a sweat after scrambling around on rough lava rock piles for an hour and a half.)

Finally, a nice picture of one of the ʻōhiʻa trees we passed while returning:

A mature ʻōhiʻa lehua tree at about 1,000 feet elevation near the entrance to the Kaumana lava tube.

Saturday, October 20, 2012

Nebula, in Three Parts

Today I've got something a little different from the usual globular cluster pictures I've had a lot of recently. This is a picture of Messier 20, the Trifid Nebula, a fascinating object in Sagittarius, the Archer.

The Trifid Nebula, Messier 20, in Sagittarius.
This nebula gets its name from the way it appears divided into three parts by the dark nebula stretching across it. It got this name long before anyone knew what it was exactly, but the number three is also important to this object for another reason: it nicely illustrates all three types of nebulae.

The first type of nebulae, emission nebulae, are represented by the reddish region at the top. This red light comes primarily from hydrogen atoms in the gas being excited by copious amounts of ultraviolet light from the hot, young stars inside and around the nebula. The particular wavelength responsible is at 656.28 nanometers and is so important and wide-spread that it has its own name: hydrogen-alpha, or H-alpha for short.

The second type of nebulae is the blue reflection nebula seen below the emission nebula. These nebulae come about from starlight being reflected off of tiny dust grains in the gas cloud. The reason it appears blue is because the dust grains preferentially reflect blue light, the same way that the molecules in the Earth's atmosphere preferentially scatter blue light. Further from the young stars than the emission nebula is, the gas in the reflection nebula isn't being excited to emit in visible wavelengths very strongly.

Finally, the third type of nebulae, dark nebulae, also come about as result of dust and are represented by the dark clouds and bands of dust in front of the emission and reflection nebulae. Dark nebulae are full of tiny dust particles containing organic molecules that are extremely effective at absorbing visible light. Soot is actually fairly close in composition to these dust particles, so you have some idea of just how dark they are in visible light. Fortunately, they are much more transparent at other wavelengths, allowing us to probe their structure in infrared and radio wavelengths.

Also, to be comprehensive, there is a fourth type of nebula that typically gets its own name: planetary nebulae. These are really a subset of reflection nebulae, as they are the puffed-off atmospheres of old Sun-like stars that are being illuminated by the white dwarf core of the star, but they are different enough from typical emission nebulae to warrant their own designation.

Sunday, October 14, 2012

Volunteer Reward Pins

Saturday night was the annual Volunteer Appreciation Banquet that the VIS puts on every year and which I was able to attend for my volunteering experience prior to becoming employed. Every year the banquet recognizes all the volunteers who have volunteered at least 25 hours over the past fiscal year, along with special awards and recognition for those who go above and beyond in their efforts. This is my fourth time attending and marks my third year coming up Mauna Kea, as my very first time volunteering was on the night of banquet in 2009.

This year we have what I hope will catch on as a new reward in the form of little pins for the hats we give volunteers who have enough hours to attend the banquet. The idea was thought up jointly between me and one of my co-workers, who happened to be in charge of the banquet this year. Since she was actually an art major before switching to astronomy she designed the pins and I hand-copied them on the computer using Inkscape to get them in a digital format where we could have them printed on pins.

Anyway, we weren't able to get too many of them physically created for the banquet (we hope to have them more fully realized next year), but I thought I'd share some of the pictures with you. When I get time I'll try to post some pictures of the pins that we did manage to get printed.

These, as you can probably guess, are for the number of volunteer hours people contributed per year. Five hundred and above are pretty rare; I think we had three people this year who had a thousand hours, all of them retired and able to come up frequently.

This one's for volunteering to do a summit tour. I really like the quiet, majestic look it has.

This one's for attending the banquet this year. I had a lot of freedom in choosing the font when converting my co-worker's hand-drawn designs to digital images, and I think this one came out nicely.

This is for participating in a trail maintenance operation, where we hike down the summit trail from the top of Mauna Kea to the VIS picking up trash along the way. Originally we had a different, much more detailed picture for this one, but when we got the first batch of physical pins in we realized that it wouldn't translate well (the pins are smaller than these pictures appear on the screen). My co-worker didn't have time to come up with a new design, so this is the only pin that I actually designed myself. I'm pleasantly surprised with how well it came out, actually.

And, this one's for the transit of Venus, naturally. Simple and elegant.

Edit (10/18/12): And here's a picture of the first four pins that I found on my phone:

Monday, October 8, 2012

Glossocratic Considerations. Also Whistling.

Last week I was happily whistling to myself as I often do while listening to music, and found myself wondering: if motor actions in the body are usually controlled by the opposite hemisphere in the brain, what part of the brain controls the tongue?

Turns out not to have a simple answer, or it if does, I haven't found it yet. The closest I could find was references to an area of the brain known as Broca's area in the left hemisphere of the brain that seems to be involved in the production of speech. However, from what I can tell that area doesn't actually contain the motor neurons that control the tongue, but simply sends the motion information to them. So, unless someone out there knows more about it than I do I'm going to assume that the tongue is controlled by both hemispheres of the brain given its location along the line of bilateral symmetry of the human form.

Also, in the course of writing this blog post I did a little research on whistling which completely took over my original purpose for writing it. I have a pretty good memory for music, and when I'm listening to music I like or know I tend to (often unconsciously) do something along with it such as tapping my fingers or, yes, whistling. And yet, I'm the only person I know who really does this, so it's always been a bit of a lonely hobby. So you can imagine my surprise upon learning that there exists an International Whistler's Convention held every year for the past 30 or so in Louisville, Kentucky, where whistlers come from all over the world to compete for the championship.

From hard experience I have learned that very few people seem to appreciate my whistling, so it's rather gratifying to watch videos of some of these champions getting standing ovations from crowds. (And personally, after watching quite a few videos of great whistlers, I don't feel untoward saying that with some more practice and dedication I could be nearly as good, especially as I figured out the technique of circular breathing entirely on my own before ever even hearing of it, allowing me to whistle continuously without having to pause for breath most of the time.) It's too bad that more people don't whistle these days, as it truly is the instrument of the Everyman (and woman); anyone can whistle, without need of expensive instrument or lessons. It used to be a fairly widespread artform, with many performers in music halls being know for their skill. In the past, when people have asked me if I play a musical instrument, I've usually said no, since while I used to play the harmonica I've hardly touched it in years. In the future, however, I'm going to proudly reply “yes – the uniquely human instrument”.

Tuesday, October 2, 2012

Globular Cluster Photo Series (Part 26): NGC 5466

Today I have a picture of the surprisingly sparse globular cluster NGC 5466 for your perusal. NGC 5466 is located very far away in the constellation Boötes at 51,800 light-years from Earth, making it the third-farthest I've shown so far after M53 and M72. At this great distance its larger-than-average size of 166 light-years in diameter gives it a visual angle of 11.0 arc-minutes, about a third the width of the full Moon. Interestingly, NGC 5466 makes nearly an isosceles triangle with Earth and the galactic center, being about 52,800 light-years away from the core.

NGC 5466 in Boötes.
As you can see from the picture NGC 5466 lacks any sort of concentration in its core, in sharp contrast to most globular clusters. It's almost difficult to tell that it's a globular cluster at all. In fact, under the globular cluster classification scheme devised by Harlow Shapley in 1927, NGC 5466 is a class XII, the most loosely concentrated class there is (class I being the most highly concentrated towards the center). You may have noticed that there is general lack of stars both in the globular and in the foreground of this image; this is because Boötes is located away from the galactic plane, and thus there are relatively fewer stars between us and the cluster.

Finally, in an interesting historical aside, it turns out that NGC 5466 was discovered by William Herschel exactly two hundred and five years to the day before I was born, back in 1784.