I won the Brian May "A Kind of Magic" contest from Astronomy magazine

I have been informed that my essay titled “A Different Kind of Magic” was one of two winners of the Brian May “A Kind of Magic” contest sponsored by Astronomy magazine.

As most of you probably know, Brian May is the former lead guitarist of the renowned rock band Queen.  Brian stopped his research for his astrophysics PhD in the early 1970s to begin his decades-long stint with the band, but a few years ago went back and finished his doctorate in 2007 at the age of 60.  The publishers of Astronomy were inspired by his accomplishment of a lifelong dream so many decades after he had started it.  Thus, they created the contest in his honor and named it after one of Queen's hit songs.   Each entry was to be a short essay on what the writer would do if he or she could “magically” go back to school to become an astrophysicist as Bryan had done.  In my essay, I told the story of how I have been doing exactly that, with the unswerving support of my lovely wife, Julie.  The prize awarded is a signed autographed copy of Brian’s PhD thesis: A Survey of Radial Velocities in the Zodiacal Dust Cloud.

You can now see the essays from both myself and my co-winner on Astronomy’s website: http://www.astronomy.com/akindofmagic

I am very proud to say that my co-winner is 11 year old Jay Mosley.  The story of his ambition to obtain a PhD in the study of hazardous asteroids is sure to be as inspiring to others as it was for me when I read it.  This young man is bright and motivated with a long productive future ahead of him as an astrophysics researcher.  Congratulations, Jay, and I envy you!

Seldom Seen Mercury

My wife Julie and I have been walking for exercise in the early morning from about 5:50AM to about 6:45AM.  The last couple of mornings (August 17 and 18) we have been enjoying a triple line up from the horizon to about 10 degrees from the zenith of Mercury, Venus and Jupiter.  All of them about equally spaced from each other.  Had it not been cloudy for the couple of mornings prior, we would have glimpsed it before our first sighting.  Mercury will no longer be easily visible by the finish of the week ending August 25, though the other two planets will still be prominent for some weeks to morning observers.

Mercury is the most elusive of all of the naked eye planets since it moves faster in its orbit than any other planet and during must of its orbit appears too close to the Sun to be observed because it is the closest planet to the Sun.  It also appears very low to the horizon so that even distant trees and buildings can hide it, so there will be few places where one can have an unobstructed view.  But for a few days every few months it appears far enough from the Sun to be easily seen given no obstructions: sometimes in the very early morning and at other times in the late afternoon.

Because of the transient nature of Mercury's appearance in the sky, many amateur astronomers have never seen it.  Johannes Kepler (the first person to show that the planets travel in ellipses around the Sun and also the first to precisely figure their orbits) never saw Mercury his entire life!  He figured the details of Mercury's orbit from the observations of Tycho Brahe.  I myself have only personally glimpsed Mercury a few times prior to my latest viewing.

So if you didn't get a chance to see it this time in the morning, late afternoon opportunities will be available in early October of this year.  Another morning apparition will occur a few months after that.  It will keep alternating from morning to afternoon to morning as the year wears on.

Try to spot this fast moving messenger of the classical gods.  If you do you will be in the ranks of the few people who have spotted it. Then you won't suffer the fate of poor Kepler!


Update: My thanks to Shawn Carlson, Executive Director of Labrats Science Education Program, for his kind compliment of this article.

Key Note Presentation at Starfest 2012

I will be a key note speaker for Starfest 2012 on Saturday, October 13, 2012 at Bays Mountain Park and Planetarium near Kingsport, Tennessee. My presentation will start at 10:30 AM and is called "The Magellanic Clouds: What nobody knew until now." Be prepared to be amazed at the latest astonishing discoveries concerning our Milky Way's two most prominent satellite galaxies. These discoveries include many findings that have yet to be published in either Astronomy or Sky and Telescope. This talk and slide show has been very enthusiastically received on prior occasions.

A Public Astronomy Presentation in Columbia, SC

I will be giving the presentation "The Magellanic Clouds: What nobody knew until now." at the June 7th meeting of the Midlands Astronomy Club in Columbia, SC.

UPDATE
I had an enthusiastic reception for my Magellanic Clouds presentation at Midlands Astronomy Club.  There were some very intelligent questions asked by the audience at the end.  I picked up a number of Twitter followers and Facebook friend requests from this one.  Several told me afterwards that they particularly enjoyed learning about things they had never heard of.

A Camera Obscura from an Oatmeal Box or "Look Mom! No lens!"

Copyright 2011 Rick Boozer

Here’s a way to make science fun for young people and curious adults! The materials you will need are common household items. This project is simple to make and very easy to use, but young children will need adult supervision. I hope that teachers will find this article useful for classroom instruction. This is Part 1 of a two part experiment that will be added to my blog in the near future. The second part is based on this first part and will be about how to make a simple astronomical instrument that will do something amazing!

In this first article, we will be making something called a camera obscura. Of course, everyone knows that a camera records images on film or a light sensitive chip, but a camera obscura projects an image you can directly see. Most camera obscuras use a lens to project the image, but in ours a pinhole will do the projecting. I hope you will enjoy making the camera obscura and will return for the next installment.

Let’s get started! Here what you will need:

• One round oatmeal box with a plastic lid
• Pencil or an object with about the same size point
• Aluminum foil
• Cellophane tape
• A small nail

The hole that does the image projection will be punched into the bottom of the oatmeal box and the screen on which the image will appear is the translucent plastic lid that comes with such a box. However, to do it right the hole and box must be prepared properly.

Before you make the hole you need to know that the smaller the pinhole, the sharper the image. There’s some science here, but I don’t want to get ahead of myself, so I will talk about that later. But just know that if you make the pinhole too small, it will not let enough light through and your image will be very faint. I have found that a good pinhole diameter that gives the best compromise between detail and brightness is about 1.5 millimeters.

So, let’s make the hole in the bottom of the box. It is very important to get a smooth round circle for the hole, and such a smooth round circle is practically impossible to make in cardboard. The solution is to punch a much bigger hole than is needed with a pencil or other sharp pointed object. Next make your small projection hole by taking a small piece of aluminum foil and, with a tiny nail, carefully and gently punch a hole about 1.5 millimeters wide. Turn the nail gently to get a hole that is very circular with no jagged looking edges. Tape the piece of aluminum foil onto the bottom of the box such that the hole in the foil is over the center of the hole in the cardboard. To reduce reflections that can cause glare in your images, either paint the inside of the box black, or be lazy like I am and cut a piece of black construction paper to the right size and line the inside of the box with it.

Now, with the plastic lid secured at the top of the box aim your camera obscura toward a bright lamp or overhead light fixture. What do you see? An image of your subject, but it appears upside down! What?! Why?!

Let’s talk about the really fun part of science . . . discovering and understanding the why!

But before we move on, here is photograph I made of an image of an etched glass light fixture projected by my pinhole camera obscura onto the lid. Notice the detail you see in the shapes on the glass.

Figure 1: An actual pinhole camera obscura projects an image of a glass light fixture on to the box lid.

If you look closely, you may be able to see natural camera obscuras in the real world. For instance, if you look where a tree is casting a shadow on a bright summer day, you will notice that the gaps between leaves act as pinholes that project tiny circular images of the sun onto the ground. These are especially interesting to watch during a solar eclipse when you can see the images go from circles, to half circles and then to crescents. On a night when the moon is bright enough to cast sharp shadows, you can see very faint little circular images of the moon on the ground as well.

But why does a pinhole project an image similar to a lens? And why does the camera obscura project images of objects upside down, instead of upright?

In the following illustrations the small circle on the right side of the oatmeal box represents the pinhole (it is drawn oversized). The arrowheads represent the direction the light is travelling from the object to the pinhole that will be projecting the image. The light then passes through the pinhole to the back of the box where it strikes the lid to make the image.

Take a look a Figure 2. Notice all of the light beams coming from the object cross exactly at the center of the pinhole, finally reaching the lid in the back of the camera obscura to light up the image. I have seen this type of illustration to explain pinhole projection since I was a child. Unfortunately, this common example is not accurate. It portrays all of the light rays crossing exactly where the hole is, and that is not what happens. Before you can understand why this is wrong, you need to have some idea of how a pinhole can create an image.

Figure 2: The way camera obscura projection is usually portrayed.

First think of the light coming from the object as being, not a solid cone of light, but a whole bunch of long round beams of light, with each long beam being the same width as the pinhole. Instead of talking about all of the light beams that are coming from the object, let’s keep things simple for now and think about only two of those beams.

One beam will be coming from a circle at the top of the object, and the other beam from a circle at the bottom of the object. A beam of light always travels in a straight line (unless is it made not to do so). Think of the beam from a laser pointer, which is just a thin bright beam of light. Figure 3 illustrates this situation with the two beams coming from opposite ends of the object: one coming from the top of the object, the other from the bottom.

Figure 3: Light beams from opposite sides of the object. (Click to enlarge)

The beams of light from each of the two circles cross each other somewhere in the region that I have colored yellow. That region’s thickness is the same as the diameter of the pinhole. The two beams first begin to cross outside of the box in front of the pinhole and quit crossing at someplace behind the pinhole inside of the box. They don’t do all of the crossing at the pinhole as Figure 1 wrongly indicated! This fact is not important right now, but will be very important when we do the astronomical experiment that is to come in the second article.

The most important thing to notice now is that the light in the beam that started at the top of the object ended up at the bottom of the image because the light traveled in a straight line that is slanted downward. For the same reason, the light beam from the bottom of the object ended up at the top of the image. Their positions in the image are flipped from what they were in the original object!

Do you see now why the image is upside down? Circles of light from the top half of the object end up in the bottom half of the image. Circles of light from the bottom half of the object end up in the top half of the image. Thus, the image gets inverted!

The following figure shows the original object with small circles on the object to indicate where each light beam starts.

Figure 4: The original object with circles added to show where the light beams start.

Figure 5: The image showing circles where the light beams strike the lid.

Each pinhole size circle on the image is a small amount of light from a small circular area on the original object whose image is being projected. In other words, the light illuminating each small circle in the image shown in Figurer 5 comes from a corresponding circle on the opposite side of the original object in Figure 4. If you are familiar with the way computer images are generated with pixels, you can think of each small circle as being a pixel in the image. This is part of the reason why a smaller pinhole gives a sharper image: the smaller the circle (or pixel) the finer the detail.

So the light in circles on the top of the image comes from circles in the bottom of the original object, light in the circles at the bottom of the image comes from circles at the top of the object, light in the circles on the left of the image comes from circles on the right of the object, and light in the circles of the right of the image comes from circles on the left of the object. The image is upside down and backwards!

Figures 4 and 5 are a good way of showing you how the image is created, but these illustrations aren’t exact. In reality there are many more circles of light creating the image. The lighted circles are not really in nice neat rows barely touching each other. Neither are there any little unlit gaps where the edges of the circles don’t touch. Instead, the circles partly overlap each other. Because of the partial overlapping, there are no tiny gaps where the image isn’t lit. This overlapping causes some blurring. The blurring can be minimized by keeping the pinhole as small as possible, but still big enough to keep the image bright enough to see well.

Of course, your camera obscura can be used to view other objects besides a light fixture. Not all objects are bright, so if you want to see images of fainter things, you can drape a dark cloth over your head that also covers the lid end of the box. The more light you shut out with the cloth, the brighter you image will appear. But you’ll notice, every image appears upside down!

If you understood most or all of this, then you have just learned some fairly sophisticated physics about the behavior of light. You’re a budding Einstein!

Next article: using the principle of the pinhole camera obscura to create a precise astronomical instrument made from simple commonly available parts.

One more thing! My thanks to my wife, Julie, for helping me make this article sound less scholarly.

QSOs: Faraway Objects with Local Relevance

Copyright 2011 Rick Boozer

In my earlier article about the experience of earning my Masters degree, I mentioned that, “I learned so many fascinating new things that I never suspected, nor had I ever seen them mentioned in any popular astronomy publication. For instance, in certain unusual cases, there is a way to use radio signals from quasars to give image resolutions of less than a microarcsecond. That’s much finer than the Hubble Space Telescope’s best resolution and even better than from the widest baseline radio interferometer with dishes on opposite sides of the world!”

After some reflection, I thought it might be a good idea for me to share some of the cutting edge information about quasars with fellow astronomy enthusiasts. Indeed, as shall be shown, astronomical discoveries may have unexpected practical applications. Thus I wrote this article. However, before I cover the new stuff, some background information may be in order.

In astronomy it is not unusual that a strange new discovery is considered too far away to have practical uses, but later reveals a useful application beyond anything that came to mind when it was first detected. For instance, helium was discovered from its absorption lines in the Sun’s spectrum long before it was physically identified on Earth. This observation sparked a worldwide search until it was found in certain oil wells in the U.S. Of course, this discovery brought the myriad industrial and scientific applications for which helium is now used. No wonder the name of this gas is derived from the Greek word Helios meaning Sun.

In this article I present information about a very strange and incredibly remote type of object that at first glance may appear to have little significance to our understanding of local phenomena or our everyday lives. However, these objects offer surprising new investigatory directions into the understanding of interstellar conditions within our own small section of the Milky Way galaxy, while also yielding at least one “down to Earth” practical application and a possible utility that future interstellar travelers may want to use.

Quasi-stellar Objects or QSOs are some of the brightest known objects in the universe seen in gamma rays, X-rays, ultraviolet and visible light. It is not unusual for a QSO to shine at a level millions of times greater than the entire radiant output of our galaxy! QSOs appear extremely faint because of their cosmically extreme lookback [1] distances of anywhere between nearly a billion to around 13 billion light-years. Though they are not stars, they are usually seen as a star-like point of light and so are called quasi-stellar. Of course, even members of the general public have heard the name for a special type of QSO that emits very strongly in radio frequencies: quasar for quasi-stellar radio object. Somewhat confusingly, it is not uncommon nowadays for scientists to call a QSO a “quasar” even when referring to a QSO that does not appear as a strong radio emitter.

The Nature of the Beast

Residing at the very center of a host galaxy, the source of the QSO’s immense radiant power is an Active Galactic Nucleus AKA an AGN. An AGN consists of an enormous black hole massing the equivalent of hundreds of millions or even billions of Suns along with a surrounding accretion disk of swirling matter that is pulled inward by the black hole’s gravitational field.

It is the accretion disk that is the source of the intense radiation. Heat induced by the compression of continually in-falling gases piling up within the accretion disk brings the disk to incandescent brilliance.

The intense magnetic field produced by the rotating black hole attracts some of the accretion disk’s matter away from the disk. Matter siphoned off in this manner then gets shot out in two opposing continuous jets of plasma near the black hole’s north and south magnetic poles. In some instances, the strength of the black hole’s magnetic field is so strong that the plasma is ejected at speeds approaching that of light! This plasma may emit magnetically induced radio emission that is highly polarized, known as synchrotron radio waves. A classical quasar’s strong radio signature is the result of this synchrotron radiation.

The tiny star-like appearance of a QSO is not only due to its enormous distance, but also its relatively compact physical size. Shortly after their initial discovery in the 1960’s, it was observed that the optical brightness of an entire QSO would sometimes vary drastically over time periods as small as several days. Because nothing can travel faster than light, these short pulses in increased brightness would imply that the AGN could be no bigger than the distance light could travel from one side of the QSO to the opposite side during the fluctuation period. Thus it was deduced that the size of the emitting part of a QSO could be no more than mere light-days to light-months across: a distance much smaller than the typical separation of stars in the tightest packed part of a normal galaxy. Indeed, the radiation equivalent of billions of Sun’s can be confined to a region within the AGN that is roughly on the scale of our own Solar System’s diameter! As the reader will see, sophisticated observational techniques developed in later decades confirmed the relatively small size for a QSO’s AGN and even allowed a highly accurate direct measurement of its diameter.

The short-term optical variation is normally the result of processes occurring within the QSO itself. A description of what is known of these processes would fill a long article all by itself; therefore, coverage of this topic is not appropriate for this short written piece and would also deflect our attention from other interesting features of QSOs. From this point on, our focus will be on observed variations in a QSO’s radio emission and some surprising discoveries associated with these observations.

The Mystery of Rapid Radio Signal Variations

One perplexing problem presented itself when radio intensity variations measured in hours were seen. It was calculated that for these fluctuations to be in the QSO itself, that the QSO’s temperature would have to be at least 10¹⁹ Kelvin! This temperature seemed absurdly high. Quantum mechanics dictates that any body with a temperature greater than about 10¹² K should emit copious amounts of a special type gamma ray known as inverse Compton radiation. (Savolainen and Koralev 2008) It then seemed unlikely that the QSO was actually causing the radio fluctuations when no inverse Compton radiation was detected. (Tsang and Kirk 2006) Clearly some mechanism external to the QSO must be in play.

Observed radiation fluctuations, whether they are in visible light, radio or any other part of the electromagnetic spectrum are called scintillation. All of us have seen scintillation of visible light with our own eyes as the twinkling of stars in the night sky and an explanation of this twinkling may give some insight into its radio counterpart.

In the case of visible star scintillation, turbulence in the upper atmosphere causes changes in the optical properties of a high level layer of air to make the starlight seen by an observer appear to either vary rapidly in brightness or cause equally fast apparent shifts in the star’s position. Astute sky gazers may notice that even when the stars twinkle noticeably, any planets that are visible at the same time will shine with an unvaryingly steady light.

Why is there a marked difference in the perception of these two types of objects when light from each is passing through turbulent cells of air? The farther away from an observer that an object of a given physical size is, the smaller it appears to be. Expressed differently, the object’s apparent size measured as an angle will be smaller with increasing distance. Turbulent air cells generally measure but a fraction of an arcsecond across. Though a star’s physical size is much greater than a planet’s physical size and much greater still than any air cell’s physical size, the immense distance of the star is so great that its apparent angular size is much smaller than the apparent angular size of the invisible cells of air turbulence that are causing the twinkling; therefore, any changes in the foreground turbulence will greatly affect the appearance of the star. Though the apparent angular diameter of a planet may be so small that an earthbound observer will perceive it as a point, it is still proportionately much closer to the observer than would be any star. In other words, the ratio of a planet’s physical diameter to its distance is enormously larger than the ratio of a star’s physical diameter to its distance. Since a planet’s apparent angular diameter is also usually much larger than the apparent angular diameter of any cell of air turbulence, the light from the planet will appear not to vary. The following illustration depicts this principle and is, of course, not drawn to scale.

The observer’s location is marked with X and both turbulent air cells are of identical absolute physical size and of equal absolute distance from the observer. Though the star is physically much larger than the planet, the planet is much closer. Thus the apparent angular diameter, α, of the star is smaller than the apparent angular diameter, β, of the planet. The cell in front of the star has a wider apparent angular diameter than the star; therefore, the star twinkles. The same size cell in front of the planet has a smaller apparent angular diameter than the apparent angular diameter of the planet, so that the planet does not twinkle.

Getting back to radio variations of QSOs, the question being asked was, “Were the observed rapid fluctuations being induced into the signal as the QSO’s radio waves traveled through some turbulent cell of material on their way toward Earth?” The first clue that this situation might be the case came in 1998 when two radio telescopes located extremely far apart (one in Australia and one in New Mexico) made simultaneous observations of a QSO designated PKS 0405-385. When a particular intensity fluctuation pattern appeared at the Australian radio telescope, the same variation would show up approximately two minutes later at the New Mexico instrument. This situation was very strange because if the variation was intrinsic to the QSO, the same variation should have shown up on the New Mexico instrument only milliseconds later, that is, after the time it takes light to travel the distance between the two instruments. (Jauncey et al. 2002; Bignall et al. 2007; Savolainen and Koralev 2008) Soon, simultaneous observations of other QSOs revealed delay times that were often much longer.

The extremely tenuous gas and dust spread throughout the space between the stars within our galaxy is called the Interstellar Medium or ISM. Most of it contains only a few hydrogen atoms per cubic meter and is thus a better vacuum than the best that science has ever achieved, though randomly interspersed throughout the ISM are occasional denser clouds of dust and gas. As all amateur astronomers know, some of these nebulae can be seen in visible light. In other words, the nebulae may shine by reflecting the light of nearby stars or their constituent atoms may absorb ultraviolet radiation from local stars and re-emit the absorbed energy as visible light. Conversely, a cloud may be dense enough that the dust within it absorbs the light of the stars behind it, producing what appears to be a black void within the sky that is commonly referred to as a coal sack. Another alternative may also occur where such a cloud is so extremely thin that it may be transparent enough as to be nearly or completely optically invisible.

After the observations were made by the Australians and Americans, astrophysicists were strongly suspecting that QSO radio scintillation could be the result of turbulent cells as the radio waves from the QSO pass through the last type of cloud described in the immediately preceding paragraph. That would explain the excessively long difference in arrival times seen at the widely separated radio receivers. In other words, a particular turbulent cell might induce a characteristic fluctuation pattern at the Australian radio telescope, but that same cell might have to travel a few minutes before it was in a position to cause the same fluctuation to appear at the American radio telescope. Other corroborating evidence was needed to clinch this conclusion, but that confirmation was not long in coming.

Something very strange began to be seen in very short-term radio intensity variations in QSOs that went up then down over time spans ranging from minutes to several days. A gradual orderly change in these short-term scintillation patterns showed up over the course of a year and the same cycle of change repeated again on following years. (Jauncey et al. 2002; Linsky et. al 2007; Savolainen and Kovalev 2008) As any scientifically literate person knows, a year is the time it takes the Earth to complete one orbit around the Sun. It was soon realized that this was the clincher as far as proving that scintillation was being induced by material in the ISM relatively close to us. The speed of the Earth’s orbit around the Sun is around 30 km s^-1; however, the speed of the material in the local ISM is also close to 30 km s^-1. (Jauncey et al. 2002) When the motion of the Earth is approximately parallel to the velocity of the ISM, they have a low relative speed and the variation of the scintillation pattern is slow. But six months later, when their motions are in opposite directions, they have a high relative speed and the variations are observed to be much faster. Thus, we are given conclusive proof of two facts: 1) that the variations are turbulence induced scintillation and 2) that the Earth indeed orbits around the Sun a la Copernicus! (Jauncey et al. 2002; Savolainen and Kovalev 2008) After this conclusive evidence was obtained, short-term variations of QSO radio intensity were christened Interstellar Scintillation or ISS for short. Any turbulent interstellar cloud inducing radio variation is called a screen.

But the evidence got even better. When computer models were constructed using the fluctuation times as input data, the theoretical predicted distance and position for each screen was almost a perfect match for a known “local” thin interstellar cloud that was at least barely detectable in either visible light or ultraviolet light! (Linsky et al. 2007) All of the evidence put together was about as close to a smoking gun as one ever gets in science.

Super Sharp Seeing in the Radio Spectrum

But here is the exciting part. Those same radio variations can be used to reveal fine details of the structure of a QSO in far greater resolution than any ground-based or orbiting telescope is capable of accomplishing! For decades the finest resolutions astronomers attained were achieved using a technique called Very Long Baseline Interferometry or VLBI. VLBI involves multiple radio telescopes observing the same object at the same time but separated by thousands of kilometers to give them the same resolution as a single stupendous radio telescope with a dish as wide as the distance between the two most widely separated radio telescopes. However, the scintillation technique even out-performs VLBI. The previously introduced analogy of visible atmospheric scintillation when stars twinkle may be extended to illustrate how such incredibly fine resolution is obtained.

Remember that if an object located behind a turbulent cell of air (from the point of view of the observer) has a smaller apparent angular diameter than the cell, the object will appear to scintillate. But if the object has a bigger apparent angular diameter than the cell, no twinkling is seen.

What if an observer was able to somehow detect a turbulent air cell and measure its apparent angular diameter? During the course of a night, a number of different turbulent air cells of varying diameters might come between the observer and an observed object. The observer would then be able to notice the maximum apparent angular diameter of a cell that caused twinkling and a minimum apparent angular diameter for a cell that did not cause twinkling. He/she would then know that the apparent angular diameter of the observed object would have to be an angle with a size between the diameters of the former and the latter.

As mentioned before, turbulent cells within an interstellar screen cause the radio scintillations that are equivalent to atmospheric twinkling. The method described in the immediately preceding paragraph has been used to measure the extremely tiny angular diameter of various QSOs. In fact, the resolution obtained is so fine, that astronomers have even resolved structures within the AGNs of some of the closer QSOs!

Angular resolutions on the order of 1 micro-arcsecond can be achieved. In comparison, this resolution is around 1000 times finer than that of the Hubble Space Telescope at its shortest usable wavelength! (Jauncey et al. 2002) And since the distance to a QSO can be determined from the amount of cosmological redshift observed in its emitted light [2] (grist for another entire article), the actual physical size of the QSO can be calculated from its apparent angular diameter. In this case, even assuming a QSO is halfway across the observable universe at a lookback distance of about 6.8 billion light-years, a structure of a mere three light-months in physical diameter can be measured. (Jauncey et al. 2002)

Clues of What’s Closer to Home

But just as radio scintillation can be used to gather information about a QSO, it can also be employed to investigate the properties of interstellar space in our neighborhood. This convenient situation is the result of the fact that the screening clouds have to be relatively close to our solar system. How do we know this? There is a maximum distance away from us that a turbulent cell of a particular physical size can be and still induce scintillation in a QSO. This distance is where the apparent angular diameter of the cell equals the apparent angular diameter of the QSO. Any farther away would lead to a situation in which the angular diameter of the QSO would be greater than the angular diameter of the turbulent cell and thus no scintillation would occur. (Bignall et al. 2007)

So the fraction of material capable of producing fast variability is restricted to the ISM in the Sun’s vicinity. Furthermore, the scarcity of detected screens relative to the overall number of QSOs observed indicates that such clouds of scattering material are few and far between in our immediate section of the galaxy. (Bignall et al. 2007) ISS observations indicate that there are on average 1.7 screens along any line of sight, with a typical line of sight usually having between only 1 and 3 screens (Linsky et. al 2007)

One may wonder what produces the turbulence in the interstellar cloud material. It is thought that areas of the highest scintillation-causing turbulence occur at places where the outer edges of two or more of these clouds come in contact with their different speeds of motion and travel direction. The slightly different velocities of the two clouds produce turbulence where they interact. (Linsky et. al 2007) Because they are on the outside of the cloud, these border edges lack shielding from ionizing radiation put out by one giant blue-white star that is relatively near our Solar System and several local white dwarf stars. The result is a much larger than normal number of fast freely moving electrons that increase turbulence to an even higher level, making these interacting areas hot beds for the production of scintillation. (Linsky et. al 2007)

Finding Our Way Around the Earth with QSOs

Everyone nowadays is familiar with the Global Positioning System that employs a fleet of special navigational satellites in Earth orbit. GPS has pretty much totally supplanted celestial navigation for ship and airplane travel. Even more immediate to people’s everyday lives is the fact that the technology has trickled down to the individual level in the form of automobile navigation systems and emergency location in life or death situations.

But to figure locations anywhere on the face of the Earth within an accuracy of mere meters requires exacting determination of satellite positions at ultra-precise times. Constantly occurring variations in the tilt of Earth’s axis have to be continually taken into account for the system to function with pinpoint accuracy. The tilt variations are detected by referencing the locations of QSOs because their distances are so immense that their motion is not detectable as a change in the object’s position and thus they “stay put” in their apparent relative places all over the sky. VLBI measurements have been used to obtain precise positions of a number of QSOs and have been compiled into a catalog to serve as base navigational references. The catalog is called the International Celestial Reference Frame abbreviated ICRF. (Ma et al. 1998)

Beyond Terrestrial Navigation

Finally, it would stand to reason that QSOs might eventually be used as a natural “galactic” GPS in the event that humanity ever achieves the capability to travel multiple light-year distances. Extremely miniscule changes in observed relative positions of QSOs in relation to each other would be attributable to a traveler’s change in position within the galaxy and thus could be used for navigation purposes. Assuming measurement capabilities continue to progress as they have heretofore, it is not unreasonable to expect that equipment to measure such incredibly minute deviations may be achievable by any future civilization technically advanced enough for interstellar travel.

Who knows what other uses we’ll find for these exotic objects as time goes on?

For that matter, what as-yet-to-be-conceived applications may follow once we know more about the nature of what we now call dark matter and dark energy? After all, those two vaguely descriptive names were chosen because we couldn’t choose better ones since we don’t really know what those properties physically represent!

In short, judging by the past history of scientific discovery, it would seem unwise for anyone to say that any particular realm of scientific knowledge will always only be of purely academic interest.

References

Bignall, H.E, D. L. Jauncey, J. E. J. Lovell, A. K. Tzioumi, J-P. Macquart, and L. Kedziora-Chudczer “Observations of Intrahour Variable Quasars: Scattering in our Galactic Neighbourhood” Astronomical and Astrophysical Transactions, 26 (2007) 567 - 573

Jauncey, David, Hayley Bignall, Jim Lovell, Tasso Tzioumis, Lucyna Kedziora-Chudczer, J-P Macquart, Steven Tingay, Dave Rayner and Roger Clay, “Interstellar Scintillation and PKS 1257-326” ATNF News (October 2002)

Linsky, Jeffrey L., Barney J. Rickett, and Seth Redfield “The Origin of Radio Scintillation In the Local Interstellar Medium”, The Astrophysical Journal, 675 (2008) 413-419

Ma, C, E. F. Arias, T. M. Eubanks, A. L. Fey, A.-M. Gontier, C. S. Jacobs, O. J. Sovers, B. A. Archinal and P. Charlot, “The International Celestial Reference Frame as Realized by Very Long Baseline Interferometry”, The Astronomical Journal, 116 (1998) 516-546

Savolainen,T. and Y. Y. Kovalev. “Serendipitous VLBI Detection of Rapid, Large-amplitude, Intraday Variability in QSO 1156+295” Astronomy and Astrophysics 489 (2008) L33-L36

Tsang, O. and J. G. Kirk “The Inverse Compton Catastrophe and High Brightness Temperature Radio Sources” Astronomy and Astrophysics 463 (2007) 145-152

Footnotes

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[1] The lookback distance is how far the light traveled from an object to reach the Earth. In the case of the farthest detectable QSOs, this distance is about half of the true present-day distance between the Earth and the QSO – called the comoving distance. The reason why is that the universe was continually expanding while the light was en route, causing the Earth and the QSO to become further and further apart during the transit time as the space between them was stretched wider by the expansion.

[2] A wave of light is lengthened (i.e., cosmologically redshifted) because the space it is traveling through is stretched by the continual expansion of the Universe; which in turn, stretches the wave of light. Some inaccurately term it as a cosmological Doppler shift. But the relative motion of a light emitting object, not the Universe’s expansion, causes a true Doppler shift!

Obtaining a Master of Astronomy Degree in Astrophysics Online

copyright 2011 Rick Boozer

The University Medal

ATTENTION: Since this article was written, the Centre of Astronomy has moved from James Cook University to the University of Southern Queensland.  People interested in obtaining a Master's degree as described in this article should apply at USQ.

At the age of 58, I achieved a dream I had had since the age of 8: to get an advanced degree in astronomy. Without leaving my home in the southeastern United States, I had attended classes for three years at a large state university located on the other side of the planet! Astronomy enthusiasts in general may find my experiences to be interesting, enlightening and even surprising in certain instances. But there is a second audience for this article as well. The online alternative is not suited for everyone who may be considering an advanced astronomy degree and the information provided here may be of help when attempting to make an intelligent decision in this regard.

Beginning the adventure

My reasons for waiting so late in life to start my academic odyssey are not relevant to this article. It’s enough to say that four years prior to getting the Master of Astronomy in astrophysics, I left a successful career as a software engineer to pursue my childhood dream full bore.

After the initial decision to obtain the degree, it became necessary to decide how to go about it. I live in South Carolina and there is no institution close to my home offering an astronomy degree. Normally, I would have to attend a school in another state, pay higher out-of-state tuition, and incur the extra expense of paying for living quarters. Robbing the nest egg my wife and I had built was not an option.

Would one of the internet-based astronomy master’s degree programs offered by a couple of institutions in Australia be the solution? Those two were Swinburne University and James Cook University with main campuses in Hawthorne, Victoria and Townesville, Queensland respectively. Both are large state universities where tens of thousands of students physically attend classes on campus.

A credible way to go?

I had two questions: 1) How do these institutions rank academically relative to other universities worldwide? 2) Can either of these programs suit my particular goals?

The first place I looked was a widely recognized rating list for post-secondary education called the Academic Ranking of World Universities (ARWU.org). At the time of writing this article, out of the approximately 9,000 universities worldwide, Swinburne is ranked within the upper 400 to 500 universities, whilst James Cook is listed in the top 300 to 400. Though not exactly in the stratospheric heights with Harvard or MIT, they do rank well compared to many respected U.S. universities. For instance, Swinburne shares its range with Auburn University, Kent State University and LeHigh University. Also, James Cook ranks with Clemson University in my home state, George Town University, Syracuse University, Texas Tech and others. These rankings are very similar to what they were in 2006 when I started planning.

James Cook’s Master of Astronomy degree program (or MoA) is split into two tracks: the History track which is well suited as preparation for teaching astronomy at college level, and the Astrophysics track for those who also want the option of pursuing astrophysical research. Swinburne does not formally specify two tracks named History and Astrophysics for its Master of Science in astronomy program, but it appears students choose a curriculum that is equivalent to either of these two directions. There was a time when Swinburne’s website stated that their courses did not provide preparation toward a career in professional astronomical research, but it appears they have since modified their curriculum for this direction.

JCU claims that their master’s program is a “combination of course-work and research” allowing a path toward a professional career via a progression from the Master of Astronomy program to a Doctorate of Astronomy and finally to a PhD in Astronomy or Astrophysics. An MoA graduate who has demonstrated outstanding ability may be allowed to skip the intermediate degree and go directly into the PhD program. Also, JCU’s PhD program partners the doctorial student with a prominent researcher in his/her chosen field (at a major university in the U.S. or elsewhere in the world) to serve as a principle supervisor, along with a co-supervisor and associate supervisor.

Swinburne’s tuition was lower, but in my case the extended options following the James Cook master’s degree were attractive. However, for someone whose primary focus is to save the maximum amount of money on tuition and/or move away somewhere to get a doctorate after obtaining a master’s degree, Swinburne may be as good a choice.

What you need before you start

To be considered for a master’s degree in astronomy, a bachelor’s degree is a prerequisite. Preferably, that earlier degree was in a physical science and included some fairly advanced mathematical training and scientific problem solving. In my case, the science was geology with added extensive courses in advanced mathematics, physics, and engineering. If your bachelor degree was in something other than a physical science, you might still qualify for entrance into an astronomy master’s degree program. Such a person would have demonstrated an extensive interest and activity in astronomy at a fairly advanced level for a significant amount of time.

I have given astronomy presentations to many general civic organizations, astronomy clubs, and even to one major conference of amateur and professional astronomers. At almost all of them I am asked a question similar to this, “What do I need besides my bachelor degree and passion for astronomy before I enroll in a master’s degree program?”

Remember, mathematics is the language of science. Brush up on the advanced math you may have forgotten, such as: algebra, geometry, trigonometry, spherical trigonometry, vector mathematics, differential calculus and integral calculus. I spent at least a preliminary year doing just that and it was a definite advantage. Once classes began, I pulled in a little part-time supplemental income tutoring those same subjects. There is no better way to gain proficiency in mathematics than having to explain it to someone else!

Assuming you are married, another important asset is a very understanding spouse who is just as committed to seeing you through to your goal as you are. Said spouse will need an enormous amount of toleration and patience when you become a nervous wreck and lose your personality during one of the grueling semester final exams. How and why my sainted wife put up with it, I’ll never know!

Experiencing the program

My fellow students and I interacted with each other and the instructor via web-based applications. I will skip the particulars of how all of this online communication was done in order to focus on how the academic content of the course and interpersonal interaction affected my classmates and me. We didn’t confine ourselves to our latest assignment and would often have lively online discussions about various timely astronomical topics of interest that one of us would bring up. This thought provoking and easy exchange of ideas was one of the most enjoyable parts of the experience. Not a few friendships began in this way between people scattered around the globe! Even now since graduation, some us still keep in touch.

Students are not supposed to give detailed help to other students, but offering a clue as to the right general direction to go is not discouraged. Private communication with the instructor is done via electronic messaging or email.

Another thing, even though Australians and Americans both speak English, the fact that words or phrases may have very different meanings in each country can sometimes cause frustration when trying to understand a lecture or assignment instructions. There is an old joke that the English and Americans are two peoples separated by a common language. The same situation sometimes applies to Australians and Americans.

Because the JCU program is the only one with which I have direct experience, it is the only program on which I can give extended details. The first course is called “Introduction to Astrophysics”. Its purpose is to comfortably ease students into the rigors of scientific study. Though providing a fairly sophisticated introduction to classical Newtonian physics, quantum theory, relativity and the latest frontiers of astrophysical science, the math gets no more complex than plane and spherical trigonometry. For all courses except the last two, an online lecture is administered on a weekly basis and a homework assignment given. Since Swinburne’s introductory course uses the same textbook as this course, I imagine the two courses must be very similar to each other.

Again excluding the last two courses, a research assignment is added every two to three weeks requiring the student to either directly acquire data through observational research or use supplied computer software to analyze and manipulate published observational data. You learn scientific rigor fast or you won’t make a good grade on your research project. Occasionally these projects contain so much data that students are encouraged to form teams. Such multi-student projects hone the collaboration skills that are so important when working in any science. The final paper explaining the student’s work and results is usually supposed to be written in the same format that scientific research journals expect; that is, starting with a general abstract description, details of methods used, conclusion, references in the proper format, etc. During these projects I learned so many fascinating new things that I never suspected, nor had I ever seen them mentioned in any popular astronomy publication. For instance, in certain unusual cases, there is a way to use radio signals from quasars to give image resolutions of less than a microarcsecond. That’s much finer than the Hubble Space Telescope’s best resolution and even better than from the widest baseline radio interferometer with dishes on opposite sides of the world!

All courses end with a final exam, excluding the last two. To be honest these tests are somewhat exhausting affairs involving complex analysis and problem solving with a completion time limit of 24 hours. However, there was one that had a time limit of 48 hours and consisted of two parts!

After the first course, the classes steadily become more advanced: Astronomy Instrumentation (from radio through gamma rays and particle detection), The Solar System and so on. Again, I have noticed that some textbooks are common between JCU and Swinburne for the applicable subjects, but the courses do not necessarily have the same name.

Courses on both the History and Astrophysics tracks are identical until they diverge after the scientifically and technically intense Galactic Astronomy and Cosmology course. How intense? One of the questions on the final exam involved deriving the equation for finding the smallest possible mass of the primordial black holes that are thought to have formed during the Big Bang. Though I sometimes felt frustration, I enjoyed this course immensely because I came to understand things that I never thought I could have. I eventually got so into it; I often did problems in the textbook that were not assigned. One of the most surprising of these unassigned challenges was to produce a mathematical proof of Einstein’s assertion that the speed of light is the same for all observers. I say surprising because, unlike most of the unassigned problems that I solved, no calculus was involved and I used nothing more advanced than 11^th grade high school algebra to do the proof!

After coming this far, some students may decide that doing advanced astrophysical science doesn’t suit them. They can then withdraw from the program with a “Graduate Diploma of Astronomy” rather than continue towards the master’s degree. I tried unsuccessfully to talk a classmate out of taking this option, pointing out to him that he at least passed Galactic Astronomy and Cosmology when some failed it. Alternatively, any student in such a situation who had originally pondered taking the Astrophysics track could choose to continue in the History track instead.

Anyone who intends to go the History track route and receives a good grade in Galactic Astronomy and Cosmology would definitely understand how science is done on a fundamental level. After they obtain their degree, these newly minted science educators are less likely to mindlessly teach rote methods of problem solving to the next generation of students and instead pass on a basic understanding of principles from which those methods came. Thus, future bright young minds would be exposed to critical reasoning skills needed to advance scientific knowledge.

The fork in the road

As mentioned before, I took the Astrophysics track after Galactic Astronomy and Cosmology. Thus, I can only state general points about the History track. The final two courses in that direction are called Scientific and Technological Developments in Astronomy and Pilot Research Project. The former is a detailed overview of the development of astronomy through the ages up to the latest discoveries, advancements, and trends. It is meant to train the student in the archival research skills and document preparation techniques necessary for the research project that is to follow in the next course. The final course covers some astronomical topic of the student’s choosing that is of historical or cultural significance and culminates in a formal research paper on that topic.

On the Astrophysics track the final two courses are designated Astronomy Literature Review and a final Pilot Research Project. The first course consists of the acquisition of yet more research skills that will be needed for the astrophysical research project in the following course. The student learns how to find important technical background information relating to the subject of his/her research in various scientific journals, databases and other professional sources. It also covers prerequisite document processing of research articles in special data formats or printing formats that are often required by professional astronomical journals. After each skill area is covered, the student demonstrates his newly acquired knowledge in a formal scientific paper on a cutting edge topic.

Despite the last astrophysics course being called The Pilot Research Project, not quite the entire course is consumed with the final project. At the beginning, techniques of astronomical image processing are covered along with relevant technical details of image data formats that need to be understood for proper preparation of astronomical research images. Techniques and software for performing such tasks as astrometry and photometry are also covered.

My final research paper involved an attempt to photometrically detect an exoplanet that had been previously discovered by other means. My final results showed that the planet does not transit its parent star within one half of a degree of the line of sight between the star and Earth. I could have gotten definite results for even wider angles, but the images were shot by another party who did not carefully follow precise image acquisition procedures. It was a lot of work, but by the end I felt very satisfied with a definite sense of accomplishment.

Receiving the degree

During the three years I was working on my Master of Astronomy degree, it was the primary focus of my life. Out of all the people in the classes in which I was enrolled, only one other classmate and I made the dean’s list during my first year. In my second year, I was the only one of my classmates who did so. After the final year, I was awarded the University Medal (pictured at the beginning of this article) “for outstanding academic achievement at the Master’s level”. Receiving the medal was a surprise and I did not know until afterward that it is given for accomplishment considered beyond cum laude. I truly believe those achievements were not because of superior intelligence or ability, but primarily because of the freedom I had to totally commit to my goal and the moral and emotional support from my life partner. In short, my wife earned the degree as much as I did and I thank her for giving the 8 year old his dream fifty years later.

How would I rate the overall experience? First and foremost it is my opinion that the astronomical education I received was at least as good as what I would have gotten at many reputable universities and even better than some. I have heard of astronomy degrees awarded where students were taught “cookie cutter” science. That term refers to a situation where only specific methods for solving certain types of problems are taught whilst requiring none of the actual original thinking or creativity necessary for advanced scientific research. My experience was by no means one of those situations. The total tuition cost for my Master of Astronomy came to about $18,000 U.S., but I think I got my money’s worth.

I am currently pursuing my PhD doing cutting edge research into the physics of compact H II regions. Maybe I’ll continue my math and science tutoring while I do so, but I now also have the credentials for teaching an astronomy course at a local college or to write an occasional science article for a popular magazine. After I finish my PhD, I plan on doing professional level astrophysical research and/or teach university level astronomy/physics. Regardless, I hope to excite the general public with a sense of wonder about science and inspire to action those seasoned astronomy enthusiasts who may have the inclination to take their interest to another level.

UPDATE: Because of financial difficulties I am currently experiencing, I withdrew from the PhD program.  I regret this necessity because I was getting good evaluation reports from my adviser.   I wish to thank renowned astrophysicist Miroslav Filipovic for being my adviser during my PhD studies and truly appreciate his efforts on my behalf.

Also, attaining my Master's degree with High Distinction was a lifelong dream and a proud accomplishment made even sweeter with the award of the University Medal.  That is enough for me at my age.  But my wife has sacrificed too much and there are too many other things we want to do for me to continue the tuition drain on our finances.  Most of all, it's time she got to make some of her dreams come true without my pursuits financially standing in the way.

I am continuing doing astrophysics research on my own.   For instance, there are a number of images that I shot years ago that I plan to use for photometric research into variable stars and/or possible exoplanets.