Adventures with astronomy

I recently finished reading "How I Killed Pluto and Why it Had it Coming", a book by Mike Brown about his work exploring the Kuiper belt and how it led to Pluto no longer being called a planet. I was surprised at how strongly I reacted to the book, but then I realized that this was the first time I had read a history book about events that were in some sense related to my life. Most of the science history books I've read were about things that happened before I was born or when I was too young to be involved in anything. But this one was about events that happened while I was at MIT.

The book starts in December of 1999. That is a month which I remember quite well. It is the month my first grandmother died. It is the month that Mars Polar Lander crashed into Mars. And for the last third of that month I have a detailed daily account of my activities from emails that I was sending. It goes through to the summer of 2005, when Mira and I had just gotten engaged and were moving into an apartment together.

There are three distinct times in my life that I almost became an astronomer. Each time, some sort of engineering intervened and I decided to be an engineer instead. The first time was at the beginning of 1986, when Halley's comet was making its way into the inner solar system. I had been hearing about the comet for a while (which for five year old me may have been just a week or two). But then the comet blew up the space shuttle. I remember seeing the news on television about the comet and the space shuttle, complete with diagrams showing something in some orbit (my memory isn't good enough to be sure what those diagrams actually were). I also remember being very upset that the space shuttle had been hit by a comet and deciding that I didn't want to see the comet any more, so I stayed inside while the comet was around and stopped looking at the stars.

Several years later in 1991, I was quite shocked when I was told that the shuttle had blown up in the Earth's atmosphere because of a failed O-ring, and that it had not been anywhere near any comets. I regretted passing up the opportunity to see a comet. This was the second time that I became interested in astronomy. At the time, we lived practically on the edge of the everglades, in a new part of Miami that had been part of the everglades just a few years earlier. The skies were fairly dark and I could see plenty. About a month later, they installed street lights on the street behind our house. One of them was in the middle of our yard. That substantially reduced the darkness and made the night sky much less interesting. At the same time, I discovered computer programming, which the street light did not interfere with. I have been programming in one way or another ever since. For the remainder of the 90's, I continued to have a mild interest in astronomy, but didn't really pursue it.

Then in the spring of 2001, I took the easier introductory planetary science class and the amateur astronomy class at MIT. I learned way more detail about all the parts of the solar system and got to use a telescope every week. I learned all the spring constellations that are visible in Cambridge (I can name as many stars as I can constellations). I had decided to take these classes because I was interested in working on interplanetary robotic missions, like Voyager and the various Mars missions, and decided that I should know something about the science as well as the engineering (I eventually got a minor in planetary science). But I found the astronomy class really exciting. I bought a small telescope and subscribed to an astronomy magazine. I learned where the planets were and started actually watching Venus and Jupiter move around night after night (the other planets mostly can't be seen from the Boston area).

In the fall of 2001, I took the real astronomy class and did a research project determining the orbit of Vesta (which is already well-known, but a reasonable undergrad project). I was also taking astrodynamics that fall, so the orbital calculations were easy for me to work out. Unfortunately, the weather did not cooperate. We only went to the observatory twice. The first time was the first week of classes, when I had no idea what my project would be. We mostly just learned how to use the telescopes. I still remember going out there on what was supposed to be a cloudless night, looking up and being disappointed when I saw a line of clouds going all the way across the sky. It took me almost a minute to realize that I was looking at the milky way, not some clouds. I had spent too much time in cities to even recognize a truly clear night when I saw one. After that, every week when we were scheduled to do our observations, it was raining.

We finally got one clear night the last week we had a chance. Normally, the class observatory trips were roughly 6pm to midnight, but because most of us had no data at all, we weren't coming back until 6am. I set up my telescope, found Vesta, and started very carefully taking a few pictures every fifteen minutes all night long. Then I had some data. But unlike people who were doing spectroscopy and just needed a few good images, I needed images that were spread out over enough time to actually see the asteroid move. An orbit is completely determined by the position and velocity, but telescope observations don't include range, so I had only the direction to the asteroid over the course of about 8 hours. I wasn't sure that would be enough to accurately determine the orbit.

I had a large number of images. I had to go through each image and mark the location of Vesta and about three bright stars that were in the image to calibrate the location of the asteroid. Then I had to write a program which would compute the angle to the asteroid in every image and the exact time the image was taken. I then fed that data into another program, which attempted to calculate the orbit of the asteroid. I wrote in my report that it should be possible to automate the bright star detection, look for things that move, and determine the orbits of many asteroids almost automatically. This was around the same time that the astronomers in the book were actually doing that very thing out in California. I was considering working with telescopes to automatically scan for orbiting bodies just as Mike Brown's project was looking for someone to do just that.

At the same time, the Mars Gravity project had just started at MIT. We were going to build a satellite to put mice into space to study how they would respond to simulated Martian levels of gravity. This seemed more interesting than looking for asteroids (and I wasn't even considering Kuiper belt objects). So I stayed at MIT for grad school and went on to get a PhD in astrodynamics. I worked on the Mars Gravity project for about three years before I finally gave up because we had insufficient funding and too much turnover to make real progress. But by then, I had committed myself to studying astronautical engineering and didn't even consider going back to astronomy.

The last major astronomical event I paid attention to was the 2004 transit of Venus. I went to the roof of my undergrad dorm (I had only moved about two blocks away and it was the best spot in the area to view sunrise from) early in the morning with my telescope and camera. I went through three rolls of film taking pictures as the clouds slowly drifted past the sun. Most of the pictures didn't come out very well (mostly because I wasn't sure what exposure time I would need), but I have about a dozen pictures of a little dot moving past the sun, sometimes with clouds obscuring parts of the image. And now the transit of Venus will happen again tonight, this time just before sunset. The current weather forecast is 100% cloud cover, so I probably won't see it. But now I have a digital camera, so it will be easier to take pictures. And even if the weather doesn't cooperate, I will probably take some pictures of planets in the next few months.

Why I studied astrodynamics

There are two stories from my childhood that provide good foreshadowing of my interest in astrodynamics. Mira told them at my graduation party, but for those who were not there:

First Story:

When I was two, we were visiting my grandmother in Florida. My mom wanted a break from her older kids (my little sister was about 6 months old), so my dad took us to watch a shuttle launch (this ended up being the only shuttle launch I saw in person). I was very excited with everyone else before the launch, and counted down with everyone. But then, as I watched the shuttle go up higher and higher in the air, it became clear that I was concerned about something and wanted to hide under the seats. My dad asked what was bothering me, and I explained that when I threw a ball in the air, it would come back down and hit me in the head. That thing over there was going up really high and looked really big, and I didn't want to get hit when it came back down.

Second Story:

When I was 5, Halley's comet was in the proper part of its orbit to be seen from Earth. I heard about this comet for several weeks as it came closer and closer. I remember being excited about this thing that was flying around the sun that only came close enough to be seen every 75 years. Then Challenger exploded. Somehow I managed to work out that the shuttle had been hit by the comet based on what the news was saying. I was very upset that the scientists at NASA had not figured out where the comet was going to be and let the shuttle fly into it. I lost interest in looking at the comet, because I was upset that it had blown up the shuttle.

And now I have completed my degree work in astrodynamics. I can make sure that spaceships will not fall on children's heads and will not fly into comets.

Just for clarification, astrodynamics is the science of determining orbits and spaceship trajectories. People who study how stars work are studying astrophysics, which is basically unrelated. As best as I can tell from what my parents have said and NASA's launch records, the shuttle launch was the first launch of Challenger, so these stories are about the first and last launches of Challenger. And I first heard about the broken O-ring that actually destroyed Challenger six years after the explosion, and was very surprised at the time to discover that the space shuttle had not been hit by a comet.

How a Thesis is like a Newborn

In the following, I use the term thesis to refer to all the work involved in completing a PhD.

Ways in which a thesis and a newborn are similar:

• both consume all of your time, significantly cutting into your social life and making you lose contact with some friends
• both seriously interfere with getting enough sleep
• both are something you put a lot of effort into in the hope that someday they will produce a meaningful benefit to the world, but you have to accept that most likely they will both go unnoticed by the world at large
• both are capable of making you feel completely incompetent and unable to do anything right for what feels like forever
• both are a good way to meet other people doing the same thing
• friends and family give you advice on both, which is only sometimes useful
• both have a very frustrating way of telling you that something is wrong, but not indicating in any way whatsoever what is wrong
• both are expected to triple in size over the course of a year (different years of course)
• both produce lots of meaningless gibberish

Ways in which a thesis and a newborn are different:

• your thesis is never going to smile at you
• your thesis never seems to be satisfied with what you have done
• your thesis's problems can't be solved in a few minutes
• nobody has claimed that putting your uncovered thesis on your naked chest is good for anything
• your thesis didn't come into the world looking like it came from an alien race, you had to spend years working on it to provide that appearance
• your thesis doesn't smell good
• your thesis doesn't look like you, your partner, or any of your relatives
• your thesis does not become more independent over time
• your thesis will not be damaged by unexpectedly rolling off a table while your back is turned
• you don't have to thesis-proof your house
• you are not genetically programmed to fall in love with your thesis
• people offer to make food for you when you have a newborn
• people do not come over and ask to hold your thesis
• people are actually interested in your newborn (some people, not everybody)
• your thesis isn't your responsibility for 18 years (I sure hope not anyway)
• you can drop out of a PhD program
• neglecting your thesis is not illegal
• you don't have to pay people to watch your thesis when you are unable to
• you get to choose a partner for raising a newborn (most of the time)
• you can't accidentally apply to, be accepted by, and enroll in a PhD program
• there isn't a committee that decides when your newborn is good enough for you to move on with your life
• removing a useless appendix from your thesis does not require major surgery
• random strangers on the subway don't comment on or try to touch your thesis
• when you first bring your thesis home, your pets don't react to it at all
• nobody asks you to track how much waste your thesis produces
• the soft spots in your thesis won't go away on their own
• if you fall asleep with your thesis on your chest, you won't wake up to the feeling of something sucking on your neck
• you don't have to buy any furniture for your thesis
• most people know what a newborn is, but have not heard of sub-Riemannian geometry or astrodynamics
• people never mistakenly think you study stars when you say you have a newborn
• you are allowed to physically damage your thesis when you are mad at it
• your thesis is not at risk of suddenly dieing because you put it down the wrong way
• nobody thinks your thesis is "the cutest thing ever"
• people don't post pictures of their thesis on facebook (or at least not large numbers of pictures)
• you don't normally put your newborn on your resume or expect him/her to be useful for getting a job later
• your thesis never learns to sleep through the night
• when your thesis does something strange and unexpected, you can't call somebody and ask if it is actually normal
• all your ancestors successfully raised at least one child, but most of them did not do academic research
• when you talk about your child, people understand the words you are using
• you can backup your thesis in case you make a mistake later or a hardware problem causes you to lose it
• most parents don't pressure their children to get a PhD
• you can pretend to not have a thesis for a few weeks before it causes a problem