Friday, November 25, 2011

Celestial Owls

Today I have a picture of NGC 457, an open cluster known by two more-evocative names: the ET Cluster, or the Owl Cluster.

NGC 457, the Owl Cluster in Cassiopeia.
Personally I prefer the Owl Cluster because to my eyes I can see the shape of an owl pretty well. Two bright stars fit as eyes, the main body of the cluster serves as its body, while slight concentrations of stars to the sides form the wings.

One interesting fact about owls is that in  many different cultures worldwide owls are considered to be harbingers of ill omen or bad luck. However, the Greeks associated owls with wisdom, so much so that Athena, goddess of wisdom, had the owl as a symbol. Given the classical roots of Western Civilization this idea carried over, and may be part of the reason that the technical term for a group of owls is a parliament.

Monday, November 21, 2011

Superluminosity...Impossibility?

Saturday I had my first day of work up at the Vis. It was kind of strange -- I've been volunteering there for over two years now, so it was a little odd being staff instead. Everything went swimmingly, however, and I enjoyed it quite a bit (although I was exhausted by the end of the day! Working 14 hours in a row is a bit tiring).

I also had some time during the day when it wasn't too busy to mull over the report of superluminal neutrinos from back in September. By chance, a report came out the next day (today) by a group of scientists from Italy that puts forward a possible proof that the neutrinos are not traveling faster than c. According to the paper, which builds on work from two American physicists, neutrinos traveling faster than light should emit gamma rays and electron-positron pairs, in a sort of weak-force analog to Cherenkov radiation.

(For those who don't know, Cherenkov radiation is produced when particles with electric charge move faster than the local speed of light in medium. For instance, light travels only about 75% as fast in water as it does in vacuum, so it's quite possible for a particle to move faster through water than light can. When one does, however, it emits a special kind of radiation known as Cherenkov radiation [assuming that the particle is electrically charged, such as an electron]. This effect is visible as the characteristic blue glow of nuclear reactors.)

Neutrinos are not electrically charged, so they don't produce Cherenkov radiation. In fact, they interact through only two of the four fundamental forces, and they happen to be the weakest two: the weak nuclear force, and gravity (this is why they're so hard to detect). However, the paper argues that in analogy with electromagnetism, uncharged, superluminal neutrinos should emit gamma rays and electron-positron pairs through weak interactions.

Now this is all well and good theoretically, but it has practical implications too: by emitting this sort of radiation the particle's own energy is drastically modified (in fact, calculations suggest that each emission would remove more than 3/4 of the neutrinos' energy). This ought to be dramatically visible in a graph of the energy of the arriving neutrinos. And to make a long story short, it's not. The neutrinos' power spectrum looks unaffected, making it virtually impossible for them to have exceeded the speed of light by the amount claimed.

This experimental test is brilliant, because instead of trying to better measure the distance or time (both of which are fraught with difficulty) it attacks the problem from another direction, that of energy. I suggested just such an experiment to measure the neutrinos' energy in one of my first posts on this subject back in October, although I admit I wasn't thinking about this particular test (I wish I'd thought of the weak-force analog to Cherenkov radiation, because it's a neat little idea). Anyway, it's nice to see the scientific method in action here, and I'll try to keep you up to date on this topic in the future.

Friday, November 18, 2011

Further Adventures with Avocados

Today I was experimenting with new sandwich fillings, and may have stumbled across the world's tastiest concoction. Tastes are subjective, I know, but this delectable delicacy left me idly licking every last bit off my taste-testing spoon while zoned out in blissful rapture for several seconds. It also happens to be incredibly easy to make: simply combine 1 medium or small ripe avocado, 2 big spoonfuls of mayonnaise, and 1 can of tuna. The resulting flavor is, well, you need to try it for yourself.

The taste by itself is sensational, but I'm sure it would also go well as a base, or could have other things added to it. Ironically, it didn't do so well as a sandwich filling because it kept spilling out, but it might serve as a dip, as a sort of enhanced guacamole.

If anyone out there tries it, let me know how it turned out!

Wednesday, November 16, 2011

Our Star

Have you stopped to ponder just how mind-blowingly huge the Sun is lately?

Last week while volunteering up at the Vis I took a picture of the Sun through the solar telescope on a whim. I noticed a large sunspot group on it, but didn't think anything else of it until this week when I learned that said sunspot group (called Active Region 1339) is one of the larger ones on record. I'd also heard somewhere along the line that it was larger than Earth, so I decided to do some visual comparing of my own. After seeing how Earth and Jupiter looked against the Sun, I decided to go all the way and add the rest of the planets. This image is the result. It shows the 8 planets of our Solar System against the Sun with AR 1339, all of them correctly sized relative to each other. (The distances between the planets are not to scale, due to the way I set up the picture.)

Our Solar System.
Look at this image, and let it sink in for bit. The Sun accounts for a whopping 99.86% of all matter in the Solar System. It's big. For fun, see how many other sunspots you can spot in this picture that are larger than Earth.

Edit (11/25/11): One other thing I like about this picture that I forgot to mention the first time is the sense of security it gives, when you really think about it. Stable orbits, despite their ubiquity in nature, are still nothing to take for granted, and it's sort of comforting seeing just how huge the Sun is compared to the Earth, and just how firmly we're caught in its gravitational embrace.

“Tremble before Him, all the Earth; indeed, the world is firmly established, it will not be moved. Let the heavens be glad, and let the Earth rejoice” -- 1 Chronicles 16:30-31a

Tuesday, November 15, 2011

Globular Cluster Photo Series (Part 14): M71

Today's picture is of the globular cluster Messier 71 in the tiny constellation Sagitta, the Arrow (not to be confused with the much larger and more familiar constellation Sagittarius, the Archer). M71 is an unusual globular cluster between 12-13,000 light-years away with a diameter of about 27 light years, fairly small for a globular cluster. It has a small apparent diameter of only 7.2 arcminutes (less than a third the width of the full Moon).

Messier 71 in Sagitta.
Sagitta is located in the plane of the Milky Way from our point of view, which explains the high stellar density in the background of this image. M71 was for a long time (up until the 1970's, in fact) thought to be a dense open cluster rather than what it actually is, a loose globular cluster. One reason was that the stars in M71 are younger than is typical for globular clusters, although that fact simply turned out to mean that M71 is a relatively young globular cluster. M71 also lacks a particular kind of variable star called RR Lyrae stars (after the prototype RR Lyrae) that are common in globular clusters, which turned out to be related to its age: its stars are too young to have become RR Lyrae-type variables yet. In fact, M71 contains only 8 known variable stars, though one of them is an interesting irregular variable.

This lack of RR Lyrae stars is one reason the distance to M71 is known to no better than a thousand light-years. RR Lyrae stars make good standard candles within our Galaxy, as the relation between their periods and their luminosities is well-known. They are also much more common than the other type of variable star commonly used as standard candles, Cepheid variables. RR Lyrae stars can be found at all angles in the sky (in contrast to Cepheids which is are strongly associated with the galactic plane), and consequently make up 90% of the variable stars found in globular clusters.

Anyway, that's it for tonight, I need to get some sleep. A hui hou!

Monday, November 14, 2011

Moon rocks!

Saturday I went up for a summit tour and stayed to volunteer because it was the University Astrophysics Club night, and the sky was actually clear after a week of clouds and rain. And I'm glad I did, because not only was I able to image four different objects (while instructing a fellow student in the operation of the imager), but some people from NASA who were there running some tests showed up with a real moon rock in a box, and a real astronaut too!

To say that the crowd was excited was be a gross understatement. (And of course they brought the moon rock on the day I decided not to bring my camera.) A lot of the students from the UAC got to talk to the astronaut too, which from what I heard was the highlight of their evening. I'd write more about it, but I'm rather tired tonight, and was actually outside taking care of things for a good portion of the time they were there.

One reason I'm tired is that I just finished an 18-page, multi-megabyte document going over the data reduction process to create pictures from the images captured by the imaging telescope (yes, collecting the data is only about half the work). I've learned a bit about data reduction over the months, so I'd like to be able to pass on my knowledge to anyone else interested in learning to use the imager who comes after me.

Anyway, I should really get to bed now.

Saturday, November 12, 2011

Avocado Adventures

Recently I read a very interesting book called In Defense of Food: An Eater's Manifesto by Michael Pollan. It's about how many of the "diseases" associated with a Western lifestyle appear to be directly linked to the Western diet. (I put diseases in quotes because these are not, strictly speaking, caused by any sort of pathogen: I'm talking about things like heart disease, cancer, late-onset diabetes, obesity, and other similar ailments. And by Western diet I don't mean "someone who lives on Big Macs and milkshakes", but "pretty much anyone in America who buys food from the grocery store and isn't eating some unusual diet".) In Defense of Food  also talks about "nutritionism", the belief that food can be thought of as merely human fuel and reduced to its constituent chemicals. In this mindset it's easy to make food healthier -- simply remove the "bad" nutrients and replace them with "good" ones. This mindset has been the guiding policy of the American food industry for nearly the entire past century.

Now, on the face of it, this position appears reasonable. It has, in fact, had some dramatic victories, such as the discovery of vitamins. The near-eradication of such "diseases" as beriberi and scurvy stands as a monument to its success. Pollan is not saying that nutritionism is necessarily wrong, just incomplete. He makes a good point when he argues that while modern science may be able to identify all the components in a type of food, it is much less able to figure out how all those components work together in the digestive tract. There may very well be important interactions we don't know about between the nutrients in food during the digestive process that help make it healthy, in which case manually tinkering with the balance of those nutrients may not be effective or helpful. Evidence that simply knowing the nutrient value of foods is not enough is not hard to come by. For starters, there's what's known as the French Paradox: the French eat a diet that by nutritionism's standards is wildly unhealth, yet they enjoy far better health on the whole than Americans. And that's not just because Americans are an unhealthily eating lot: according to studies, Americans are the most health-conscious people on the planet, while paradoxically also suffering from some of the highest rates of the aforementioned Western diseases.

The evidence points to the typical Western diet (even of health-conscious people) being the culprit. Again, evidence for this is easy to find: time and again, scientists during the 1900's noticed that when indigenous people switched from their native diets to the Western diet, invariably Western diseases (or "diseases of civilization") soon followed. In a dramatic demonstration of how these effects can be reversed, a group of middle-aged Aborigines in Australia suffering from ailments such as obesity and type 2 diabetes went "back to the bush" for a few months and experienced dramatic improvements to their health. (You can find a link to a quotation from the book detailing this experiment here.)

Now, some of you may be thinking to yourselves, "If the price to pay for the luxuries of modern living is being a bit obese and a higher risk of cancer and heart disease in old age, I think I can live with that." And indeed, I would be inclined to agree with you. Neither Pollan nor I are advocating a return to pre-Industrial Revolution-style conditions in order to escape diseases that, while nothing to sneeze at, are nothing compared to what mankind struggled with prior to modern medicine and agriculture. However, the question is whether there are only two alternatives: live a healthy life without modern conveniences or an unhealthy one with them. According to Pollan there is a third option, namely, living a healthy life by taking advantage of the conveniences of modern life.

Doing so, however, will require a bit a rethink of our approach to food. According to Pollan, more and more of the food found on grocery store shelves isn't so much food as it is "edible foodlike substances". While preserving food (such as by drying, salting, smoking, etc) has been around pretty much forever, much of the processing done to food on the shelves today is much, much, younger, and Pollan argues that we haven't had enough time yet to fully understand what we're doing with out diet. Prior to industrialization every culture on Earth had some sort of traditional diet that they ate and had been eating for hundreds if not thousands of years, and those diets obviously worked, else the culture wouldn't be around to be eating them. In contrast, industrialization and the accompanying changes to our food supply (and they have been dramatic changes) have only been around for 150-200 years, at most. Of interest is the wide variety in those pre-Industrial diets, many of which would not be thought at all healthy according to modern nutritional science. For instance, people have survived and thrived on diets consisting almost entirely of plants, and almost entirely of meat, and ones everywhere in between, often with large amounts of nutrients that are considered extremely dangerous today (various kinds of fat, etc.). This suggests that we ought not be too dogmatic about what we think we know about food.

There are many other things I could expand upon, such as the fact that the majority of nutrients in the Western diet now come from just four species: corn, soybeans, wheat and rice, while the number of species in the world's collective cookbook stands at over eight thousand. Or that the higher incidence of Western diseases is not simply a matter of more people living to older age, but a demonstrable effect based on diet (and lifestyle. Pollan reminds us that the two cannot really be separated). But this post is already long enough, and I'd just be poorly parroting the book, which is well-written and an interesting read. Pollan's advice boils down to seven words: "Eat food. Not too much. Mostly plants" and while I have never been one to pay too much attention to my diet before, I was so intrigued by the ideas in this book that I've decided to try to eat a healthier diet by a) paying even less attention to health claims by food than before, and b) just attempting to eat a balanced diet of real food that has withstood the test of time.

Basically, I decided to start trying out new recipes and such, so the last time I went shopping I got some avocados at the store (so THAT'S what the title is about!). I don't remember eating avocados much as a child, so I decided I'd be bold and try to make something with them. I created some guacamole, and was instantly hooked (I also learned that unripe avocados are not to be trifled with, but that's another story). In fact, I could definitely see this becoming a new favorite food in the very near future. See, Mom, I may still be a picky eater, but I do try new things from time to time. And sometimes I even like them.

Anyway, it occurs to me that I just wrote a two-page essay to describe a new food foray, but I was planning to write something about In Defense of Food anyway, so I killed two birds with one stone there. If you have any other favorite recipes involving avocados, feel free to leave me a comment! (For some reason, I've spent this entire post wanting to write "avocados" as "avodacos".)

Friday, November 11, 2011

Asteroid Fly-By Redux

Well, I've been busy getting things paperwork done for my new job, but I'd be remiss if I didn't tell you how things went Tuesday. Simply put, not much happened. There was an all-staff meeting that morning so I was shown how to use the register and ended up being left to watch the First Light Bookstore for two and a half hours, so I didn't have time to attempt to see the asteroid while minding the store. Then clouds rolled in around lunch time when I was relieved, and stayed there for the rest of the afternoon.

From the information I gleaned, I don't think it would have been possible to see the asteroid at closest approach (at 1:28 PM here) anyway. I may make an attempt to see it Saturday night when I'm up there for the UAC night as it may still be visible, but we'll see.

And boy, I'd heard that the First Light Bookstore had one of the highest profit-to-square-footage ratios of any store in Hawaiʻi, but it wasn't till I was tending the register that I really realized just how much people often spend of souvenirs.

Tuesday, November 8, 2011

Asteroid Fly-By

Just a quick post today to let y'all know that I'm going up to volunteer at the Vis on Tuesday for the first time as a daytime volunteer. This is because there's an asteroid fly-by happening tomorrow, and we're going to determine if we have any chance to see it. I need to get to bed soon so this post will be short, but basically it's a little asteroid called 2005 YU55 which is about a quarter-mile wide. It'll approach to about 198,000 miles at its closest, a bit closer that the orbit of the moon, at 1:28 PM Hawaiian time (that's 3:28 Pacific, and 6:28 Eastern time). It's only going to be about magnitude 11 even at closest approach, so more than ten times too faint to be seen with the naked eye, plus the fact that the sun will be up won't be helping at all. However, it may be possible to see in the days to come as it appears to move slower as it get further away in a direction almost opposite the sun.

Anyway, need to get some shut-eye now, so I'll write a longer post later with a bit more detail, along with any results we might possibly get.

Sunday, November 6, 2011

Telescopes and Snow

This past Thursday my Observational Astronomy class got to go on a field trip to Mauna Kea, where we were treated to tours of three of the observatories up there: the Gemini North facility, the NASA Infrared Telescope Facility, and Hōkū Kea, the telescope that will eventually be for undergraduate students at UH Hilo when they finish fixing it.

We've had quite the storm system washing over the island this past week, so there was actually snow on Mauna Kea when we went up -- and not just "small piles in places the sun hasn't melted yet", but "a pretty good covering". Since I could probably count the number of times I've been around snow on my fingers and toes, it was pretty impressive to me.

Puʻu Hau Kea (Cinder Cone of White Snow)

Looking back whence we came.

Puʻu Makanaka (the large one. I don't know what Makanaka means, perhaps a proper name)

From left to right: Canada-France-Hawaii telescope, Gemini North, the UH 88-inch, the United Kingdom Infrared Telescope, and Hōkū Kea. All looking very cold.

Part of the Sub-Millimeter Array, standing staunchly amidst the cold.

Having gotten all those distracting pictures of frozen water out of the way, I can proceed to describe the actual objects of our tour. Our first stop was the Gemini North telescope, one of two identical 8.1-meter (that's 27 feet) telescopes built and operated by a consortium of countries. The other, Gemini south, resides in Chili, so that between them the two observatories cover almost the entire night sky. The two domes are identical, and are an imposing sight close up:

The Frederick C. Gillett Gemini Telescope dome, up close.

It's hard to capture the sheer size of a telescope that has more area than the floor of my room in one shot, but I tried. The Gemini telescope is similar in many ways to the Subaru telescope, which is almost the same size. For some reason, they're even painted suspiciously similar shades of blue. I did my best here:

The Gemini North telescope. It is huge.

Since it can be hard to appreciate something when you have nothing mentally to compare it to, have another shot with some crew members working in it (that big box they're standing around is an instrument they're about to put on telescope, and yes, it's so big that they're standing on it):

Removing one instrument and swapping in another.

From Gemini we moved to the NASA Infrared Telescope Facility, a 3-meter (9.8 feet) telescope built exclusively for infrared viewing (many of the optical telescopes on Mauna Kea such as the Keck twins, Gemini, Subaru, etc. have the capability to do some limited infrared observing, but IRTF is one of the two telescopes built exclusively for it). IRTF was originally built to support the Voyager missions and to this day at least half of its observing time is taken up by planetary research. Because of this it has a somewhat unusual mount called an English yoke equatorial mount. It's something like two tuning fork stuck with their open ends together, with the telescope free to rotate in between. The advantage of this design is that it is much easier to observer objects that are very near the zenith than would be possible on a regular alt-az mount such as most of the large telescopes on Mauna Kea have.

The NASA Infrared Telescope. Note that same shade of blue paint at the bottom.

Here's another shot from below showing the telescope nestled between the two arms of its yoke:

Showing off the telescope's unusual mount design.

Finally, we ended our time on the summit with a brief tour of Hōkū Kea. It's a mere 0.9 meters, and the entire dome area is probably smaller than Gemini's mirror. It's also apart for maintenance at the moment with the mirror being down for some work, so I didn't get any interesting pictures. There wasn't much to see besides the empty tube, although it too was painted that same shade of blue. I actually asked people at each telescope if there was a reason for the color, but all I got were blank stares so I still don't know. Maybe it was just cheap.

Anyway, after our frosty tour we left to return to the warmth of Hilo, but not before I captured one more snowy landscape in memory:

Looking to the south-west, Hualālai is visible off in the distance through the clouds.

Addendum: If you've read this far you must like pictures, so you may like to check out the post directly before this one. I re-reduced my Andromeda Galaxy picture, and I think it came out a lot nicer. I added it to the post, so you can see both of them and compare. A hui hou!

Tuesday, November 1, 2011

The Great Galaxy in Andromeda

Saturday night while I was up at the Vis I decided to take a break from imaging globular clusters to try my hand at what probably pretty much every astrophotagrapher ever has broken their teeth on: Messier 31, the Great Galaxy in Andromeda.

The Andromeda Galaxy is located in the direction of the constellation Andromeda, about 2.5 million light years away. It's not the closest galaxy to our own Milky Way, but it's the closest spiral galaxy and the one closest in size to the Milky Way in our Local Group of about 30 galaxies. (Intriguingly, although Andromeda is larger in size than the Milky Way, recent studies indicate that the Milky Way may have more mass. It also has a higher star formation rate, and a higher rate of supernovae.)

The Great Galaxy in Andromeda, Messier 31. Technically, only the innermost part of it. M32 (at top) and M110 (at lower left) are also visible.

While Andromeda may or may not be the most massive galaxy in our Local Group, there is no doubt that it's the brightest galaxy in the northern hemisphere. It's also the largest on the sky. In fact, if we could see it all, it would appear as wide as six full moons on the sky! Its huge size, however, is paradoxically what makes it so hard to see. All that light is spread over a large area, making it exceedingly faint. What you're seeing in this picture is no more than the central third of the galaxy; it stretches out on both sides almost as far again as seen in this picture (mostly because I didn't have a lot of time to image it, so I took the longest exposures I did in the time available).

Being as it is the largest on the sky and brightest in the northern hemisphere, Andromeda was the first galaxy to have its spectra taken (by Vesto Slipher in 1912) and the first galaxy to be confirmed as such (i.e. a system of star not materially associated with the Milky Way), by Edwin Hubble in 1922-23. This discovery increased the size of the known universe by several times, and was instrumental in the development of our current picture of the universe.

The Andromeda Galaxy is a fascinating star system, and I could write pages more on its various interesting features, but it's getting late here and I ought to get some sleep. After seeing how this picture came out, I'm tempted to try again and get a longer exposure to show fainter details, so perhaps I'll write more about it if I do.

Edit (11/5/11): Due to a suggestion from a master imager, I went back and re-reduced the data for this picture, stretching the light curve in a different manner to get better results. DeepSkyStacker, the program I use to do the data reduction, lets you apply different light curves to your photo after it does all the work to reduce the noise in the image. Basically, different light curves are better for bringing out different features. The one I chose (called "cube root") helped show the faint nebulosity better without simultaneously blowing out the the bright, dense core. So, here's the same picture, version 2:

The Andromeda Galaxy, Messier 31. Now much prettier!
If you compare the two pictures, you can see that the second one shows a lot more detail. I'm glad I learned how to apply different light curves, as my typical globular cluster shots didn't usually change much when I played around with them before so I wasn't quite sure what it did. But as you can see, it works wonders with nebulous subjects! (And since there aren't as many globular clusters to image during the winter, I'll probably be taking a little break from them to image some of the other cool objects in the night sky...)