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November 30 What telescope should I buy?Well, y'all need to tell me something that you want me to blog about!
For now, I'll go back to a question that I am asked a lot. People think that I should know what is the best telescope that they should buy. The idea is that because I am an astronomer, I know all about telescopes. Well, they got lucky in that I do know a bit about telescopes. That is not always the case with an astronomer. Huh? "Don't y'all use 'scopes?," you might ask. Well, sure, sort of. A great deal of work is done with remote instruments, whether they be radio telescopes operated by staff, images or data taken at a distant observatory without the astronomer present, or space based instruments. A lot of work is done using data sets collected by others, or collections of data from many observers. Some work does not directly involve observations at all, but rather is mathematical modelling. Those who do this work might check their findings with observations taken by others. All of the above, though, does not require the use of a telescope by the astronomer himself. This reminds me of a staff member of a major university's observatory that I was talking to once. He said that this person had showed up one day at the observatory around sunset, and she wanted to know if any of the telescopes there could see the star Algol. Apparently, she had just finished defending her dissertation on some aspect of the star's behavior. After her committee approved her work, she had the idea that perhaps it would be nice to actually look at the star that she was getting her Ph.D. studying. She was shocked when the staff member pointed out her star. Apparently, it didn't register that you could actually see it naked eye!
Of course, there are still a lot of astronomers who take their own data. I belong to this camp. However, even with observational astronomers, you don't always get people who can answer the question that the public asks. After all, most research is done with instruments that are hopelessly more expensive than an amateur can afford (and not portable, either!). That is not actually universally true, of course, but largely so. Knowing about research instruments does not help when someone sticks a catalog in your face and asks what to order. Many observational astronomers would be pretty sorely pressed to even use an amateur telescope. Now, again this is not universal. I know a LOT of professional astronomers who are also amateur astronomers. That is, they study the heavens for a living, but they also enjoy getting out a telescope and just looking at cool stuff, too. This is squarely where I fall. It is my love of the sky and skywatching that leads me to do star parties, public events, etc. I just like showing off my field to the public. Also, I teach introductory astronomy laboratories, and so I keep current on what equipment is out there. I try to make sure that we have a very good representative set of equipment on campus for the students to learn with. I want them to know what the different telescopes do, how they handle, what eyepieces and filters are good for what, etc.
So, people ask me what telescope to buy. Well, I don't really tell them. I ask them what they want to look at, how often they want to observe, how and where, and several other things. Some telescopes are better for some things than others, so I try to help them out to know what the plusses and minusses are for each. Some are better for planets and the Moon, others are better for galaxies and nebulae, and some do a decent job of both. Some are good for just looking, and others are set up to do photography with. Some give better images, some are easier to use, and some are more portable. Nothing really does it all. Then, I suggest that they really start with just a pair of good quality binoculars and a decent star chart. There are actually hundreds of objects that you can see with just 10x50 binoculars! And, of course, if you decide that you don't like doing astronomy after all, you can use the binoculars at a ball game. Then, I suggest that they hook up with an astronomy club, take a class, or something. There are several amateur astronomers in the area that do continuing education classes through various city parks departments. Amateur astronomers also set up telescopes downtown outside the museum a half dozen or so times per year. These sort of things give a person a chance to see different types of telescopes, to use the telescope to see what fits their needs best, and to talk to the owners to see what they think. In the meantime, they are learning the sky using their binoculars and starchart.
-Astroprof I'm still here.I am still here. However, I seem to be buried under Avagadro's
number worth of papers. Part of this is my part for setting the
due dates for semester long projects (I pretend that the students
actually started these things months ago when I assigned them instead
of over this past weekend throwing together whatever half assed stuff
that they can find.) coupled with the fact that the end of the
semester just naturally brings more papers, and of course exams.
Everything is hitting this week after the holiday. Not to
mention, of course, that I have a committee meeting coming up that I
need to prepare materials for, a faculty senate meeting coming up with
a report that I need to present, and a talk at an elementary school ---
all in the next 10 days. Oh what fun. Why do I take on all
these things? I am sure that there are several other things that
I need to do, but they escape me at the moment. Then, I get to
campus, rather stupidly thinking that I can get some work done there,
only to be interrupted every 5 or 10 minutes with some sort of thing or
another. Oh, well. Every semester seems to end this
way. I used to think when I was a student that it would be far
less frantic when I was a professor. Wrong!!!!! At least, I
am not alone. Everyone else in my department is in about the same
boat. So, with all the frantic rush today, plus a case of blogger's block (I simply can't think of what to write about next), I am just complaining. I'll have a more interesting thing to say later. -Astroprof November 28 Orion (the spacecraft, not the constellation)I have been reading a very interesting book lately. That is, the book is a bit dry, but the material is really fascinating. The author, George Dyson, is the son of Freeman Dyson (whom I mentioned in a previous post), an astrophysicist who worked on the project.
Now, for those who don't know about the Orion Project, let me explain. I first heard about this while growing up (late elementary school, early junior high, something like that). I read about it in a book about space travel. For the life of me, I can't remember who wrote the book. I am thinking Asimov, but if it wasn't by Asimov, then I am sure that he did write something along those lines. The book had a section on interstellar spacecraft, and it explained that ordinary chemical rockets simply could not gain the speed needed. Nuclear propulsion was the answer. Two types of nuclear spacecraft were described. One, the Daedalus, was expected to scoop up hydrogen from the interstellar medium along the way and fuse it to provide power for propulsion --- a sort of interstellar ramjet. The other, Orion, was propelled by dropping atomic bombs out of its back end, and the resulting explosions would propel the craft. At the time, it seemed preposterous to me, and the Daedalus seemed the be the way to go.
Well, years passed. I went to college, then graduate school. I learned a lot of physics, and I also learned a lot more about the technology that needed to be developed for these ideas to work. I also learned about a third form of nuclear propulsion: the nuclear ion drive. In this third system, a nuclear reactor would provide power to operate an ion drive engine. An ion drive generates thrust by accelerating ions to exceedingly high velocities with electric fields and shooting them out the back of the spacecraft. Any rocket thrust is proportionate to the rate of mass expelled and to the relative velocity with which it is expelled. There is a formula called the "first rocket equation" that is used to compute this. Chemical rockets can accelerate a lot of propellant to fairly high velocities. This gives massive thrust, but you run out of propellant very quickly. Ion drive shoots ions out one at a time, but at much higher velocities. The rate of mass expelled is very low, so despite the much higher velocity, the thrust is rather low. However, each ion has far higher momentum than the corresponding atoms of a chemical rocket, so ultimately the corresponding final speed of the rocket is much higher, according to what we call the "second rocket equation," which says that the final velocity is proportionate to the exhaust velocity times the logarythm of the ratio of the initial and final masses of the rocket. We now have constructed ion drives, but they get their energy from solar power rather than nuclear reactors.
So, back to the Orion spacecraft. I had always been under the impression that both the Orion and Daedalus craft were simply concepts. I presumed that some sort of feasibility study had been done to see if such things could one day be be built. With my physics background, I realized that the Orion would be much easier to build, and that it would require far less technological development. After all, we know how to make fission bombs, but we have a hard time with controlled nuclear fusion. Also, I also learned that atomic bombs don't really just vaporize everything nearby as most people think. So, a "pusher plate" with an ablative coating that would vaporize and shoot off of the pusher plate with VERY high velocity would provide an extremely large thrust. The Orion was merely an engineering problem, not a technological one. You just needed to toss a nuke out the back, let it explode, toss out another one, etc. Keep it up, and the successive pushes would accelerate the spacecraft to very high velocities. Still, these are just wild ideas, right? Wrong. This book has opened my eyes quite a bit.
Apparently, the US Department of Defense had seriously studied the Orion concept, and had even built a small working model powered by chemical explosions!!!! They even had talked with the same people who designed nuclear submarines to design prototypes of the crew compartment of the spacecraft. I was completely shocked by how far work had progressed. I never knew! Because nuclear explosions are pretty large, nuclear pulse propulsion (the official designation) has a huge thrust, and so the Orion could be a VERY large and heavy spacecraft --- much heavier than any spacecraft propelled by chemical rockets. This means that an Orion could carry more crew in comfortable quarters, along with sufficient air, water, and food, for an extended mission. The living conditions and duration of mission would be similar to that of a small nuclear submarine. There was talk of sending manned spacecraft to Mars, Jupiter, and even Saturn by 1980. This spacecraft would have opened up the solar system to human exploration! What happened?
Well, first of all, there was the issue of national security. Most of the work was classified. Why? Well, it wasn't because the military was afraid of some other nation building an interplanetary spacecraft. Obviously, if one was to be built, we'd want to do it first for the sake of national pride. But, there were far more practical reasons. First of all, nuclear pulse propulsion permitted VERY large craft. It was possible to launch a flying warship using the technology. At the time, we were in the midst of the cold war. Even without a flying warship, a single Orion could launch and deliver enough thermonuclear warheads to wipe out an entire nation. A second, though no less important reason to keep the technology classified, was that some things survive nuclear explosions, and quite a lot of research went on to explore these materials and the conditions under which they survived in the hope of using them to construct the pusher plate. Naturally, we didn't want anyone to know how to build tanks and bunkers capable of surviving nuclear explosions. Thirdly, the Orion needed rather small controlled explosions. Too big of an explosion would simply damage or destroy the craft. It turns out that it is rather tough to build a bomb that explodes with a small nuclear blast. The technology that was needed to build the bombs that would power the Orion is the same technology that it takes to build suitcase nuclear devices. Obviously, we didn't want to tell the Soviets how to build such devices, nor did we want them to figure out the properties of such devices from backwards engineering from the specifics of the bomb deployment system or the pusher plate itself. So the whole project was kept under wraps. Even today, many of the propulsion details are classified, since the technology for the nuclear pulses is exactly the technology that terrorists would dearly love to acquire (not for space travel, though, but to blow things up).
At any rate, I was surprised to find how far along the project got. It finally died, though, perhaps because chemical rockets seemed to be getting the job done for less money. Security would always be an issue with Orion technology. And finally, nuclear pulse propusion, created by setting off atomic bombs, is simply not terribly environmentally friendly. An Orion would not be something that you'd want to launch from Earth's surface. Now, if we had a permanent space base, such as in Earth or lunar orbit or even on the lunar surface, then that would be another matter. I'm not through reading the book, so I don't know the end of the story yet (if it says). Still, I thought that this would be an interesting thing to blog about.
-Astroprof
November 27 Star ColorsWell, I am back from the holiday trip. It wasn't as emotionally
stressful as it could be, but it sure was tiring. Now, I am
facing a mountain of papers to grade, an exam to prepare, and lectures
to get ready, etc. This is going to be a busy day, ... I am tired, fried, and stressed over the mountain of stuff to do by tomorrow. So, I can't think about what I should blog about. Still, I want there to be something educational to say every few days, and it's been a while. So, I figured that I'd drag out an old standby: "Why are some stars different colors?" This is a question that I get asked a lot in my public talks, school talks, etc. Most any astronomer knows the answer. But of course, everyone has to hear it the first time somewhere, right? Basically, the answer is that different stars are different colors because they are different temperatures. The cooler stars are red (cool still being thousands of degrees!), then hotter ones are sort of yellow hot, and hotter is white hot, with the hottest being bluish. Stars form from basically the same material. They are just about all 90% hydrogen (by number of atoms, closer to 75% by mass), and about 9% helium (also by number of atoms). There is very little difference in composition --- certainly not enough to change the color of the star. The biggest difference is that they form with different masses. Stars hold themselves up against the inward pull of gravity by thermal energy. This energy is primarily generated through nuclear fusion in the core of the star, when everything is ballanced, that is. The more massive the star, the more thermal energy it takes to ballance gravity, and so the hotter the star will be. The higher thermal energy requires more fusion, and so ironically, the more massive the star then the quicker it will use up its fuel (it fuses hydrogen into helium). When the star runs out of hydrogen fuel in its core, it goes through a series of changes. Most of these changes involve the core of the star either getting smaller and hotter (compressing gasses makes them hotter) or bigger and cooler. The changing temperatures of the core affect the mid layers of the star, and they will expand or contract based on the change in temperature to them as a result of the core's temperature change. As the mid layers expand when they are heated, that causes the outer layers of the star to also expand. Expanding gas cools, and so the outer layers of the star get cooler, and redder. So, strangely enough, the core collapses to a very small, very hot cinder, heating the mid layers of the star, which expand, causing the outer layers to expand and cool. All the result of the core getting hotter. At any rate, the star is big and red --- a red giant. Several other changes occur, the particular ones depend upon the mass of the star, and the star either expands and cools, contracts and warms, or goes through cycles. When large, the stars are very bright. So, stars are different colors due to temperture. When you see a red star in the sky, it is likely an old, expanded, dying star. The stable red stars (the ones that are fusing, but very small, needing little thermal energy to ballance against gravity, and thus fusing slowly) are all too small and dim to see without a telescope. The blue stars that you see are the ones that are normally still fusing hydrogen, but are very massive, and thus very hot. A few massive dying stars will turn bluer during some of the later stages of their deaths, and they also make up some of the blue or white stars that you see, but very few. OK, for those that really know what is going on, I realize that this is not very complete,but I didn't want to give my two weeks of lectures on stellar evolution here. Those that want to learn more can read up on it, or sign up for my class! Now, this applies to stars, not planets. Mars is reddish not due to temperature, but due to the fact that the surface is covered in iron oxides --- basically rust. -Astroprof November 23 Thanksgiving DinnerOK, I gave it some thought. With the bird flu scare, we don't really want to eat turkey, or other foul. Since the swine flu might flare up again, pork is out, too. Mad cow means no beef. Fish collect heavy metals, so seafood is out as well. Vegetables are coated with insecticides and so you don't want to eat them, and if they aren't then they've got bugs. Well, that leaves only one food for the holiday meal: M&M's !!!! Yeah!! -Astroprof Oh, and for my readers: I'll be out of town for a few days, and I don't know if I'll be able to post. Holiday spiritI heard a story on the news this morning. Apparently, someone was shot outside a WalMart near here after taking an argument outside that had started while in the store. Now that's the holiday spirit! See my blog from a few days ago for my frustrations over the holidays.
I was almost surprised that I only had a few students not in class earlier. This is my physics class, though, and I've already lost all but the serious students. In light of that, though, I suppose it isn't too surprising. I have some skills and background that are unusual, so I sometimes am asked to teach as an adjunct elsewhere. Frequently, I accept (I have trouble saying no). So, I've taught at nearby Huge State University and Expensive Private University. The students there seem to care less than the ones here, as the absentee rate at both institutions is extremely high on the days before Thanksgiving. I have never had so many miss around here. It is another reason that I really like my institution. We've got our shortcomings, but overall this is the best place that I have been, and I am very thankful for that.
My afternoon lab class I gave off today, since the Monday section of the class missed for Labor Day. This gives both sections the same number of meetings, and keeps them on track. The college closes at 5pm, so my night class doesn't meet. I guess that means that I am done for the day, right? Well, I still have some things to do, but it is nice not to have to worry about teaching. Now, I have time to do other things! You know, being a professor would be a lot easier if I didn't have to teach! OK, I actually do enjoy teaching, and we are into the part of the semester where we are covering some really cool stuff, and I like to see the students' reactions.
The stress of dealing with family makes the holidays tough, but it will also be nice to have a few days off. On the other hand, I'll be thinking of all the things that I'd like to be doing. I really do like my job. After all, I am getting paid to do pretty much what I think is fun: learn about things and figure things out.
-Astroprof
November 22 Lighting a town.In the newspaper, I was reading about this small Austrian town and its winter lighting problems. You see, the town of Rattenberg is built in the Austrian mountains. From November to February the Sun does not shine directly on the town. Hmm. How can that be, you ask?
As the Earth orbits the Sun, its rotational axis is inclined with respect to axis of its orbit. In layman's terms, it is tilted over 23.5 degrees. This means that during part of the year, the northern hemisphere is tilted towards the Sun, and it is summer (winter in the southern hemisphere that is tilted away from the Sun then). Half a year later, the reverse happens, and the southern hemisphere is tilted towards the Sun, making it summer in the south and winter in the north. So, how does that affect the sunlight in Rattenberg? Well, about June 21, when the northern hemisphere is tilted mostly towards the Sun, the Sun appears directly overhead for a person at 23.5 degrees north latitude (the Tropic of Cancer). The closer you are to the Tropic of Cancer, the closer the Sun will be to appearing overhead. Where I live in Texas, we are about 10 degrees north of the Tropic of Cancer, so on the Summer Solstice, the Sun appears 10 degrees south of the zenith. Rattenberg, at 47 degrees north latitude, sees the Sun at about 24 degrees south of the zenith. At the Vernal or Autumnal Equinoxes, the Earth is tilted in a line perpendicular to the line between the Earth and the Sun, so neither the northern nor southern hemispheres are tilted towards the Sun. The Sun appears directly overhead from the Earth's equator. In Rottenberg, the Sun appears 47 degrees from the zenith at noon. In other words, even at noon, the Sun is no higher than 43 degrees above the southern horizon --- not even half way to directly overhead! At about December 21, the Winter Solstice, the southern hemisphere is tilted towards the Sun, making it summer in the south and winter in the northern hemisphere. The Sun appears directly overhead for someone living at 23.5 degrees south latitude (the Tropic of Capricorn). For Rattenberg, the Sun will rise well to the southeast, and go up only to an altitude of only a measly 20 degrees above the southern horizon, before setting in the southwest. This is why the days are shorter in the winter.
This is true of anywhere with a latitude farther north than the Tropic of Cancer or farther south then the Tropic of Capricorn. The numbers that I gave before are for any city at latitude 47 degrees north. The problem for Rattenberg, though, is that an alitude of only 20 or 30 degrees is not high enough for the Sun to clear a mountain south of the town. So, from November to February, Rattenberg is in shadow. The people there claim that is is gloomy. Of course, they built the town there. After all, the mountain was there first!
So, now, they have decided that after 700 years of this situation they are tired of the gloominess. So, they want to put giant mirrors up to direct sunlight into the town during these months. This involves putting rotating mirrors, called heliostats, on a nearby mountain that will track the Sun. These mirrors will shine sunlight onto another bank of static mirrors that will in turn direct sunlight into the town. This will produce a dozen or so sunlit patches in the town.
OK, leaving aside any environmental concerns about what suddenly putting sunlight someplace that has not had it during that time of year for the last few million years, the mountain was there before Rattenberg. Also, this will cost an estimated $2.4 million according the newspaper. The EU is putting up half the money. This is all for a town of ONLY 440 people!!!!! That means nearly $5500 per person just to have direct sunlight for about three months (a luxury, since they have lived without that direct sunlight for 700 years). This is the initial cost. These mirrors and heliostats will need routine maintainance, at the cost of possibly well over $10k per year. Is this money well spent?
-Astroprof November 21 Private Moon MissionsSpaceDev, a private company, has announced that they believe that pivate industry can launch a manned lunar mission for a fraction of NASA's estimated cost. Well, Duh. Private industry can almost always do things less expensively, quicker, and often better than the government. The problem is startup cost. Developing the initial technology requires government money. Then, let private industry take over. Once that happens, and people star figuring out how to make money at something, then the field really takes off.
Look at aviation. The Wright brothers got aircraft flying, but serious advances waited for government funding of military aircraft. This pushed the technology, and these advances moved into civilian aircraft. Still, air travel was mostly in the hands of the government. Regular air routes originated as mail flights. Some took passengers. Paying passengers quickly became more profitable than carrying mail, so passenger airlines were born. With so much money going into air travel, more money was spent to make travel by air cheaper and safer. Now, flying across the country is a bargain. In real money terms (adjusted for inflation), it is about the least expensive that it has every been, as well as the safest. Space travel needs the same private enterprise.
The government has done the work paving the road to space. Already, private companies are launching more satellites each year. They can do this for less money than the government, and they have a good, and improving success rate for launches. A private company has sent an astronaut into space in a subortial flight. The next step is an orbital mission. Then, regular space travel. Once tourists start to pay to go into space in large numbers, then we'll have full access to space that is cheaper and safer than anyone dreams today.
So, I am all for a private lunar mission. If costs can be kept down, then there is even a chance that private companies can make money off of lunar minerals. Then, we'll have a real rush into space, and mankind will truly become a space faring species.
-Astroprof Moon PhotoI got the college to buy me a nice digital camera. The idea is to be able to allow the students to take a few photos during their labs and take them home. This way, they will "own" a bit of the class, and perhaps that will interest and motivate them more. At any rate, it is cool.
So, the camera came (after a lot of wrangling and explaining to administrators what I wanted it for). Then, we had to wait on the memory card. That took an undue amount of time. I can't fathom how purchasing can be so slow. OK, this is a govenment institution. That explains it.
Finally, we got everything, and I am reading the manual trying to figure this thing out. I've done film astrophotography, and CCD work, photometers, etc, but never a commercial digital SLR before. So, I took a couple pictures of the Moon. This one I took this morning around 9am. That is while the Sun is up, so I got a picture of the Moon in a blue sky. Sort of cool.
This is taken with a Nikon D70 camera set at ISO222 and a 300mm telephoto lens. I cropped the image to include just the Moon.
-Astroprof I HATE our computer network!Egad. Our network sucks.
I wrote up a very good posting about the James Webb Telescope being delayed (complete with hyperlinks, etc ). It was a GOOD blog. Well, I dutifully kept saving it as a draft. I got burned before with the network on campus locking up and losing the post. Well, students kept coming by my office. They are getting frantic with the end of the semester coming on. I had to go to teach lab. So, once I got the lab started, and made sure that the students weren't going to kill themselves, blow up the lab, or set anything on fire (we're doing a thermodynamics lab), I got back to the blog. Well, I finished up my last few sentences, and submited it. OK, that is when the network decided to do something stupid. MSN spaces is not the most user friendly or forgiving blog site (nothing Microsoft is very user friendly or forgiving to me). So, the network froze in the middle of posting, MSN timed out, and my long and truly wonderful post evaporated out into the aether. I was pissed. I mean, this is the second or third time that has happened. All from on campus. Now, I don't have this issue at home. I still have a dialup connection at home (I keep thinking that I'll get something faster, but why if I have a T1 line in my office?). But, the administrators in charge of technology here don't want to spend money. The network does not have the bandwidth for all that is going on. The servers are slow. The computers here are mostly old and don't have the memory needed for the stupid software that they install that is always trying to do something on the network. The computer in my office freezes up all the time. I have a laptop that I sometimes bring and plug in, and that works better. The laptop that I got to do field work with is very good, and that seldom every has issues, but the desktop in my office sucks. The one in the lab that I was in today sucks, though not as bad. The ones in the other lab are OK. We've got registration going on, and with both administrators and students trying to use the network, it just bogs down. When this is happening, then my slow computer with dialup connection at home is FASTER than the much nicer computer in my office with the faster connection. Stupid, stupid, stupid.
So, my cool post is gone, and y'all get stuck with my frustrating rambling and complaining.
-Astroprof November 20 Ranting about Holidays. I am going to rant about the holidays. This
will likely be long and incoherent, so y'all might not really want to
read it. It will be good for me to get it off my chest, though,
so I'll go with it. More coherent posts will follow. Well, Thanksgiving is upon us. This is an American holiday that begins what we call the "holiday season." This is really a terrible term, since that isn't what it is about at all anymore. Thanksgiving was originally something done to thank God for a bountiful harvest. OK, most of us don't harvest anything. Some time ago, it was made a national holiday for thanking in general. Yet, even that isn't what it is about anymore. In typical 20th Century American fashion, it has been completely commericialized. We get messages from the mass media that Thanksgiving is all about getting together with family, loved ones, etc, and eating ourselves silly, and having a grand old time with everyone happy and getting along great. If you don't have anyone to do this with, then you are pathetic and somehow less than those who do. Now, all of this involves travelling and buying things for the event. I think that is what it has really become. The travel industry and the media push that you are expected to either travel somewhere to be with family or else host guests. You are expected to put on a lavish meal that has way more food than even a huge group of people can possibly eat. And, you are expected to be happy about all of this. I think that latter expectation leads a lot of people to be depressed. They aren't happy about the holidays, and that gets them down. OK, so with Thanksgiving holiday here, I am expected to go visit family (and stay for a while). If I don't, there will be massively hurt feelings from my Mom. It isn't that I don't love them, but rather I have a lot to do! This has been a very hard and busy semester, and I could really use a few days to catch up before the final push to the end. I won't get them. I get even more irritated because I find myself falling into that trap of thinking that something is wrong with me because I don't have a spouse and kids of my own to spend the holiday with like the classic family portrayed in the media. Now, I don't want to do the pathetic thaw out a turkey dinner and say how messed up my holiday is. By no means! I just want a few days to catch up on work, do maintenance around the house, read, etc. I won't really get much time for that over the Christmas break, either. That brings up the second point. Thanksgiving is seen not so much as a holiday of its own, as a beginning to the holiday season. The day after Thanksgiving is the first day of the Christmas season. The Christmas season is not the liturgical season cellibrating the birth of Jesus Christ (which wasn't in the winter anyway!), but rather it is a season of buying things. In fact, that is what this is all about, really. Spending money. We are expected to spend, spend, and spend more to buy lavish gifts to show people that we love them, and then spend the next 10 months paying off credit cards for those gifts. You don't want to be outgiven by anyone else, because that would mean that you don't love the recipient as much. We are pushed to buy, buy, buy. Thanksgiving is supposed to get us in the mood to buy things. Merchants really push this, because for many of them, the few weeks from Thanksgiving to Christmas account for the bulk of their sales (for some, it is over half of their sales). This is just wrong. Why do we have to buy things to show that we love someone? How about being there for them during the rest of the year if they are having a tough time? What about being a friend when they need someone? I would MUCH rather have someone who would talk to me and spend time with me over the course of the year than someone who would buy me something expensive that I didn't really want for Christmas. I am paid very well, and I can buy pretty much anything that I really want. (That is, if it can be bought. Some things I dearly want, but they are nor for sale.) So, to make sure that everyone buys, buys, buys, we are bombarded with holiday messages from the mass media showing all sorts of happy families spending time together and sharing expensive gifts. We are shown people spending time with loved ones sharing the moments of the happy holiday season. Couples are shown enjoying these festivities with one another. So, what effect do these advertisements have? For some, they spend money. For many of us, our lives simply don't conform to the scenes portrayed. So, what do we do? Some spend more money than they can afford trying to buy the love of others. Some spend money trying to convince themselves that they really do live these sort of lives. Many get really depressed. Even knowing what is going on, and the sham of the lives portrayed on television, I still get depressed at not having someone special in my life to share the holidays with. And I know what is happening! What about those who are caught off guard and don't realize that what the media is showing is a lie? What about those who spend, spend, spend, and still can't buy love? It is no wonder that in America, suicides are far more common this time of year. So, here we go again with another holiday season. The day after Thanksgiving, there will be traffic helicopters aloft flying over shopping malls giving parking reports. That evening, the evening news will report on the amount of money spent, and make projections of how many billions of dollars will be spent on gifts this year. Unless something really disastrous happens in Iraq, this will completely displace any reports of soldiers fighting and dying, or any other significant news for that matter. All that anyone will care about for the next few weeks is spending money. There will be daily shopping reports, and reports of how much money is being spent, and how this affects the economy. The stores will be blaring Christmas music thinking that it will get people in the mood to buy more things. Of course, some have already been doing that. Some radio stations around here have gone to an all Christmas music format from now until December 26. Give me a break! Gag. And all this for what is essentially a Roman pagan holiday. Christ was NOT born this time of year (that was in the spring). Rather, there was a Roman holiday of Saturnalia on December 25. This holiday was only days after the winter solstice, which is the shortest day of the year in the northern hemisphere. It was just long enough after that you can confirm that the days are in fact getting longer. Well, to celebrate this, they gave gifts, got drunk, and danced around evergreen trees. Hmm. Sound familiar? After Christianity was adopted as the official Roman religion, people didn't want to give up their rather fun pagan holiday. So, the Church decided to celebrate a mass honoring the birth of Christ on that day: the Christ mass. Now, it is mainly a very important economic marker. We should rename it "Economy Day" or something. We won't even get into why celebrating the New Year is silly. So, Astroprof gets ready to go through another frustrating and baffling holiday season. I can't wait for January when the stress level returns to a more reasonable level! -Astroprof The life of a single college professor.When I was a student, I worked my tail off. All that time,
though, I thought that once I was done, then I'd have it much
easier. I saw my Dad come home from work, and he relaxed, did
chores around the house, etc. Seldom did he have to bring work
home. My Mom was a school teacher, and she had to bring papers
home, but not all the time. Well, it seems that my job never
really ends. I go to campus, and I teach, work in my office, am
in the lab, library, etc. Then, I have odd hours. Being an
astronomer, I often have to do my thing at night. However, the
rest of the college does its thing during the day, so they expect me to
be there to go to meetings, etc. I teach night classes, and I
have for years. I finally got the department chair to NOT
schedule me for early morning classes the next morning after my night
classes. Then, when I do go home, I have student papers to grade,
lectures to prepare, and of course my own work. I still have to
go the library, write papers, etc. I spent much of Saturday
grading papers. That seems to never stop. Next, I have
stacks of observing reports from my students to grade. I have to
prepare lectures. I was dumb enough to allow myself to get
elected to the faculty senate, and I am on a committee that requires
some research to get ready for our next meeting. I might blog on
that soon. We are about to open a can of worms. Then, I
have a colleague at another university wanting to work with me, and I
need to find time for that. Another person wants to write a book
with me. After a flurry of affirming news this past week, I am
actually in the mood for that. But, where do I find the
time? And, I have to keep up with the journals. Oh, and I
am the faculty advisor for the astronomy club. There simply isn't
time for all of this! OK, now for the rest of you in academia, I would imagine that you have similar stories. It seems that this is the sort of occupation that totally engages you. Well, it is good that I like it! After all, I really like studying and learning things, and here I get paid to do just that. Well, that is just me getting frustrations out. Now, I will get some sleep so that I can grade the rest of the papers tomorrow. And, I've got an idea for a short paper of my own, ... -Astroprof November 19 The four kings.This is a blog entry about celestial navigation. Since the Earth is spherical, every spot on the planet has a unique spot in the heavens that is overhead at any particular moment. Knowing the relationship, you can determine your location on Earth. This is the essence of celestial navigation. Generally, what we are interested in is determining latitude and longitude so that we can look at a map or globe to determine our whereabouts. Latitude is the easier dimension to measure. An approximation, to within a degree, is available from looking at the North Star (if you are in the northern hemisphere). The angle of the North Star above a flat horizon is approximately equal to your latitude. A much more precise measure of latitude is available if you can determine what is directly overhead (called the zenith). The sky can be thought of as a great sphere surrounding Earth, with a sort of latitude and longitude of its own (called declination and right ascension). The celestial coordinate of declination is a match to latitude on Earth. In fact, the declination of your zenith equals your latitude. So, if you can determine exactly what is overhead, you can determine your latitude, assuming that you have sufficiently accurate star charts or tables. Since there isn't really a Southern Star, this is basically how you might determine latitude in the southern hemisphere (actually, it is seldom done this way). Longitude is another matter. While declination is linked to latitude, longitude is not really linked to right ascension. The two coordinates are basically equivalent (one for Earth and one for the heavens). As the Earth rotates, the declination of the zenith does not change. However, the right ascension of the zenith does change over the course of the rotation of the Earth. So, you would have to know the right ascension that is overhead for each moment of the day. Worse, the right ascension of the zenith at a particular time of day changes from day to day! So, there needs to be tables and charts of this data. These tables and charts would give the right ascension that is overhead at a particular time in a particular place on Earth. Now, if you are east of that location, then that right ascension will be overhead earlier (about 4 minutes earlier for each degree longitude to the east). If you are to the west, then that right ascension will be overhead later (about 4 minutes later for each degree longitude west). So, if you have the tables and charts for a particular location, and a clock that is set to the time at that location, then you can determine your longitude in terms of how far east or west of that reference point you are by observing what right ascension is on the zenith at any particular moment. Naturally, this information would be collected by astronomers. Such information was collected and tabulated at the Royal Observatory in Greenwich, England, at one time. So, longitude would be determined east or west of that point. That is why the prime meridian goes through Greenwich. OK, for those of you who know the full story, you realize that I have seriously summarized it to fit in this one blog. While what I just said is a way of determining longitude and latitude, there is another easier way of doing the same. This involves taking sightings of certain stars. It can be determined that a particular star is overhead at a particular point on the surface of the Earth at a particular time. So, if you determine that said star is 20 degrees from being on your zenith (ie, 70 degrees altitude), then you know that you are 20 degrees away from that location. So, you can draw a circle on a map of that radius. You are somewhere on that circle. Next, you sight on another star. If it is 25 degrees from the zenith, they you draw a circle of radius 25 degrees around the spot on the map that is directly under that star at that time. You are somewhere on that circle, as well as being somewhere on the other circle. Said circles will overlap in two spots. With any luck, you will have an idea which spot is the right one. A third sighting on one additional star would have a circle that simultaneously intersected the other two at only one spot. That is your location. The minimum number of sightings is two. So, what two stars do you use? There are a LOT of stars in the sky. It would be useful to have a table of data for the absolutely fewest stars required. Well, it turns out that there are four stars that historically were often used for this purpose. These stars are near the ecliptic and are spaced roughly at right angles to one another in the sky. That means that from any latitude not more than 60 or 70 degrees from the equator, you will normally be able to always see at least two of these stars. About every 6 hours or so, you have a situation where one star is visible and two others are rising or setting. Just wait an hour or so, and you'll have two stars again. So, what are these special stars? They are Regulus (in Leo), Aldebarran (in Taurus), Fomalhaut (in Piscis Austrinus), and Antares (in Scorpius). These are known as the four Royal Navigation Stars, or sometimes the Four Kings. -Astroprof November 18 Astroprof Rocks!Well, I just got in from celebrating with some of my students and colleagues after my evening class tonight. So, what was up? (Oh, I might add, that the prof that tried to talk me out of the field eventually appointed me as head TA over a bunch of others and tried to get the department to keep me around after I finished my graduate work. A couple years ago he hunted me down at a conference to ask me advice on a project that he is working on. I don't want y'all to think that I am being vain. I just had to work really hard to overcome a bad start. So, this colors my perspective when advising students. I very rarely suggest that they quit, but rather re-evaluate how they are getting towards their goals.)
November 17 Full Moons and LunacyThis is going to be an educational blog entry. Yesterday was the full moon. This occurs roughly every 29.5 days when the Moon is on exactly the other side of the Earth from the Sun. Thus, the face of the Moon that we see gets full sunlight, which is reflected back towards Earth. ---> Full Moon Most people don't really realize how bright the full moon can be. When I got home from teaching my night class, I went out to the mail box to collect my mail. I was able to read it by moonlight, and was able to determine that the mailman had put one letter in my mailbox that really belonged to someone of the same number address, but on a different street. Now, you wouldn't be able to do that after just walking out of a brightly lit building, but it is easy to read by moonlight after you let your eyes adjust. The full moon is about 30,000 times brighter than the brightest star in the sky, Sirius. It is nowhere near as bright as the Sun, of course, being only about 1/444,000 as bright. However, the human eye is capabable of detecting an absolutely amazing range of light intensities. As for the old stories about the full moon making people act crazy, I don't think that there is lot of credence to that. Often doctors and nurses in hospital emergency rooms, police officers, etc., will say something like "Wow, we are busy tonight! It must be a full moon!" Then, without even checking, everone else assumes that it actually is full moon, and so they think that they have evidence that the full moon makes people act crazy. If they do happen to go outside and look up and don't see the Moon, then they just figure that it must be behind a building or something. The actual scientific studies that I've seen don't really show a lot of evidence supporting this contention, with only a couple of exceptions. One problem is that most studies done are done with poor sampling procedures, no real control groups, etc, so any results are suspect. I try to look at only the really well done studies. I did read a few such studies done some time back that indicated that there was a very slight increase in violent crimes around the full moon, but only in urban areas. My feeling is that people are simply more comfortable being out at night if the Moon is full or nearly so, making it easier to see outside. With more people outside, particularly drunk people right after a night of drinking, then you simply have more interactions, which leads to more fights, arrests, etc, and an increase in violent crime statistics. Even so, it is marginal. More recent studies don't even show this increase, and that may be because there has been a significant increase in outdoor lighting at night, so the Moon lighting things up has had less of an effect. Just my hunch, completely unsubstantiated. -Astroprof November 16 What's my grade?Well, right on the heel of Profgrrrrl's post on grading, I had students asking today, "What's my grade?"
They are more focussed on the grade than on learning. As Profgrrrrl points out (very well, I might add), the system has its flaws. The students want to know a running average. I don't do that. I have a spreadsheet with a formula built in to get their grade. It is pointless to keep a running average, I think, since each part of the class is weighted differently. I have a fairly complicated algorithm to determine the final course grade. No matter what grade they have now, it can go up or down a couple of letter grades with what we have left to do. If it were only tests, or only homework, or some such, all evenly weighted, then that would be different. There is still a lot to do in the semester. So, if they would focus less on grades and more on doing the best that they can with the remaining assignments and exams, then they would likely do better. Besides, I give them the algorithm in the syllabus, so they really should be able to figure it out for themselves (if they tried).
So, why the sudden push to know their grades? Drop date is upon us. We have some administrators around here that babble on about retention, as if it mattered far more to have lots of students than for them to learn a lot. So, they want us to think about strategies for improving retention. Well, I've got one. Change the drop date! It is so fricking late in the semester, that students will go all the way through, and then decide whether they like the grade they are going to get or not to determine whether or not they are going to drop the class. As a result, the weaker students, or the ones that don't really care, don't try as hard as they could. After all, they can drop it right near the end if they are not doing well. If the drop date were back in September, then they would have to commit to the class once that date were passed. That would make them work harder and learn more. The other problem is that it is too easy to drop the class. When I was a student, to drop a class we had to be the signature of the professor involved. Around here, that is not required. They just go to the registrar's office and fill out a form. Well, now they can actually do this over the internet. All they get is a dialogue box asking "Do you really want to drop this class?". They click "Yes" and the deed is done. They don't have to give a reason for dropping. They don't even have to speak to anyone who might be able to advise them on whether or not to drop the class. And most troubling, they don't even have to speak to their professor, who might be able to tell them that they are doing better than they think.
Oh, well. I can't really change the procedures by myself, and some actually like it this way. So the students will keep asking me what their grade is, and I will keep telling them to calculate it themselves based on the graded work that I've handed back. And a lot of them will drop the class on the last day to drop.
-Astroprof
Urban tumbleweeds.A sharp cold front came through here yesterday. The wind was really blowing as it came through. The temperature dropped 30 degrees in just a couple hours. What a change! It was warm and humid when I left for campus, and was COLD when I got done with my night class to head home. It is always interesting when these sharp fronts come through. Being an astronomer, I am often outside at night. It seems to me that the differences are sometimes more sudden at night. I remember a long time ago in graduate school standing outside talking with some of the other TAs after they we had just taught an outdoor lab at the observatory (actually, they had done it as a backup lab indoors because it was cloudy), when suddenly the temperature just dropped about 10 degrees. I've experienced that a number of other times since.
Anyway, so this front came through. Naturally, they seem to hang up as they approach here so that they can wait and rush through on garbage day. All up and down the street people had put the trash out for pickup. Then the front came and started catching milk jugs, papers, boxes, etc and blowing them down the street. We have curb-side trash pickup, so we have to put the trash out by the curb on garbage day. Then when our garbage truck comes by, the guys collecting the garbage tend to just toss the empty garbage cans back in the general direction of the lawn. Well, it was really windy, so after the garbage truck had come and the garbage collectors had tossed the empty cans back, the wind would catch them. All day they were blowing towards the south end of the street (I live on a north-south street). When I got home last night, there was a pile of empty garbage cans pushed up against the fence at the end of the road. Urban tumbleweeds.
At least it finally turned cold. I had to turn on the heat for the first time this season when I got up this morning. The forecast is for it to freeze tonight. This has been an unusually warm autumn for us around here so far.
-Astroprof November 15 Planet GeorgeWell, now for a blog entry on astronomical history.
I just gave a little public seminar on planets, and in particular the "new" tenth planet announced back a couple months ago. I'll say more about that in a later blog, though, if y'all are interested.
In order to talk about planets, you need to know what you are talking about. So, what is a planet? The term comes from the Greek for a wanderer. The ancients would look up and notice that the stars were always in the same place relative to one another, and so you could imagine shapes and figures in the sky, and these shapes and figures would remain constant. That was true except for five "stars" that moved from constellation to constellation at varying speeds. These were Mercury, Venus, Mars, Jupiter, and Saturn. Oh, and the Moon also moved between the constellations. And, if you dimmed the Sun enough to see the stars behind it, then it, too, seems to move between the constellations. So, that makes seven "planets." Hey, there are seven days of the week, too. The Sun's day, the Moon's day, and even Saturn's day. The others are named after more Teutonic gods, but in Latin, French, or Spanish, they are clearly named for the planets.
Astronomers eventually realized that the Sun is not a planet, and in fact the planets orbit the Sun. The Moon orbits Earth, so they figured that it shouldn't be a planet. That made the planets Mercury, Venus, Earth, Mars, Jupiter, and Saturn. Additionally, moons were found around Jupiter and Saturn. Eventually, in 1781 William Herschel and his sister Caroline Herschel discover a small disk in the sky using his telescope. Well, after observing for a bit, he realizes that the disk moved. But, the only things that moved were comets and planets. It wasn't a comet. So, he realized eventually that it was a planet. He decided to name it George (actually, Sidus Georgium) after King George III, in whose name he had gotten a grant to build a telescope. So, the Solar System was Mercury, Venus, Earth, Mars, Jupiter, Saturn, and George. The name didn't stick, so the planet was renamed Uranus. However, King George III made William Herschel and his sister Caroline royal astronomers to the king.
Not long afterwards, astronomers began to find tiny objects between Mars and Jupiter. At first they were thought to be planets, but no matter the magnification, they were never more than dots in the telescope. That meant that they had to be very small --- too small to be planets they figured. So, the term asteroid was coined to descibe them. They are small rocky things. Some are the size of houses, others are hundreds of miles across, with every size in between. At one time, there was speculation that the asteroids might be a planet that somehow was destroyed, but we now believe them to be relics of the formation of the Solar System. They never did get together to form a planet.
After watching the orbit of Uranus for long enough, astronomers also realized that there must be another planet beyond it that is interacting with it gravitationally. A search for the object netted Neptune. That is a really fascinating story, too, about how Neptune was discovered.
Pluto is weird, so we won't deal with it just now. It is way too small to make the list of planets if it were discovered today. It made the list by accident. The new object is slightly larger than Pluto, so that is why the media called it a planet. But, there are objects of the same composition that are just a tiny bit smaller than Pluto, and some a tiny smaller than they, and so on. Where do you make the cutoff?
Unfortunately, it turns out that astronomers never got around to making a definition of a planet. It just seemed so obvious. Hmm. Oh, well. It is really just a label, anyway. So, if you ask me, there are multiple categories of objects, and it isn't fair to lump them all together under one umbrella term "planet." After all, Jupiter and Earth have very little in common other than that they orbit the Sun. Earth and Venus have a lot in common, and Jupiter and Saturn have a lot in common with one another. So, maybe we need to refine our definitions.
-Astroprof
November 14 The astronomical price of textbooks.Every now and then, I look at the price of the books that our students buy, and I am amazed. The price is simply staggering. To make it worse, they can't really buy used books because the textbook publishers are always coming up with new editions. The publishers say that they have to put out new additions all the time to keep current. Excuse me? For some fields, I can see that. For my introductory astronomy classes, there is actually a LOT of new information, or different information, that is relevant to the class. There are always new discoveries. This is a very dynamic and exciting field. However, for my introductory physics class, nothing has changed. In fact, the introductory physics class that I teach is basically the same class that I had. The big difference is in the problems. My old book had a student placing a penny on a rotating record in a record player. We had to calculate how far out we can place the penny before it slides off. The new book has a problem with placing a penny on a rotating CD and calculating how far out from the center the penny can be placed before it slides off. Big deal. Same problem. It goes on, with similar Earth-shattering changes and updates. So, why a new edition every three years (or more!)? Well, my old book did not have color photos. The new book has lots of color photos. That, and the new book costs about $120 more than mine did. You students had better enjoy those pictures. You are sure paying for them! Other than that, there is VERY little difference. There has not been a discovery of a new Newton's law, nor an updated speed of light, nor any other such thing bearing on first year physics.
Besides driving up costs, new editions are extra work for me. Now, if I didn't actually make assignments out of the textbook, then that would not be such an inconvenience for me. It is particularly annoying if the book rep doesn't even bother telling me, the prof, that they are coming out with a new edition. On a couple of occasions, I have made out my syllabus, only to be surprised when students walk into class with a newer edition than mine! Hey, I thought that the bookstore was supposed to order what I adopted. Right? Well, they said that the publisher would not sell them the old edition so they got the new one. And no one bothered to tell the prof teaching the class?!?!?
Again, some books I can understand such rapid changes. My intro atronomy, for one. Some upper division books, perhaps. But every textbook in every subject? What, has Shakesphere written a new play lately that we need a new Shakesphere textbook edition? Was a new edition needed to correct typos that somehow were missed in the previous six editions of the book? The book reps tell me that they need to keep changing editions to force students to buy the new books instead of used ones. They also say that they charge so much for textbooks because they don't sell as many as they used to due to the very active used book market. Well, Duh!!!!! They charge so much for books, that OF COURSE students will buy used books, and they will sell back their old books to afford to buy a new one for the next semester. If the books were more reasonably priced, then students might keep the more interesting ones, and perhaps buy more new ones.
The textbook companies have us all over the barrel (especially the students). They need the books to do well in the classes. So they can charge as much as the market can bear. Most faculty don't look at how much the textbooks cost.
Anyway, that's my little rant from my soapbox on textbook prices.
-Astroprof November 13 Can we set up the telescope indoors?In the category of amusing questions, here is one that I got several years ago. This was during the time that a comet was visible. I think that it was probably Comet Hale-Bopp. It was pretty impressive naked eye, but wonderful with the telescope. So, we scheduled several public comet nights at the college. Wouldn't you know it, one of those nights a storm system was moving through. It was raining cats and dogs. I think that there was even a bit of hail mixed in. Well, I was standing in the hallway talking with an amateur astronomer that worked on campus, and who would have been helping if it had been clear, and then this couple came running into the building from out in the storm. They, came up to us and asked, "Is this where the comet viewing is going to take place?" My friend said, "Well, it was. But, it's raining so we can't do it." One of them asked, "Why can't we do it if it's raining?" I think that my friend was too flabbergasted to reply, so I said, "Because we can't set up the telescopes out in the rain! Besides, even if we could, it is cloudy, and we couldn't see anything." So, they turned to leave, and as they were walking off, one turned and came back and asked, "Well, how about if you just set up the telescopes inside where it isn't raining?" I honestly don't remember what I said. It was probably something to the effect that the telescopes need to actually see what they are looking at, or some such. The question just floored me. Sadly, I have gotten that question a few times since. Enough said. -Astroprof |
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