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.

Solution to the Jesse Puzzle

Hi! I'm Jesse. I'm 14 months old and still learning to talk and walk. My parents are Mira and James. If you need help with this puzzle, ask them. They have a lot of practice.

If I'm saying anything with a nasal consonant (M or N), it probably means I'm hungry. Or I'm saying no, which is mostly just a game I play (but I'm starting to mean that I am unhappy about something when I say no). "mi" is milk, "mo" and "mah" mean more (which means food), and "mamami" means mama milk (which means I want to nurse). Sometimes I repeat these words really rapidly and it is hard to tell which one I'm saying. It mostly doesn't matter, because if I'm hungry and get some kind of food it will make me happy.

What I don't eat: candy, cookies, or anything else a responsible parent would call a dessert. Just kidding, I love eating those, but my parents for some reason want me to eat healthy, nutritious food, and I generally don't eat enough of that to be allowed to eat anything else. They say something about wanting me to be healthy and growing. Also, I don't like my food to be sticky or gooey (at least not when I first get it - I like to make my food sticky and gooey by putting it in my mouth for a bit and then taking it back out).

What I do eat: This is the first bonus puzzle. I almost always like crackers, bread, peanut butter, and berries. I eat many other things, but I use a semi-random process to decide what I am willing to eat at any given time. If you offer me some food, I will probably eat it. But maybe not. If I don't want to eat something you are offering me, I will push it away and shake my head no. If you continue shoving it at me, I will start screaming and crying. Nobody wants me to do that, so please don't try to force me to eat things. You should also check with my parents and get a bib before feeding me.

If I give you a book and say anything resembling read (probably "reee", but sometimes "eed"), it means I want you to read the book to me. I might lose interest before you finish and take the book away from you. Don't take it personally, I'm only 14 months old. If you read the whole book and I say anything with a "G" in it (often "geh"), it means I want you to read it again.

If I am crying: This is the second bonus puzzle. About half the time, this means I am tired. About a third of the time, it means someone is doing something somewhat obvious that I don't want them to do (taking me away from my parents, eating food in front of me and not sharing it (that is so rude), playing with MY toys, etc). The rest of the time I have unlocked the super-secret special bonus puzzle. Do not attempt to solve this puzzle. You will fail. My parents have practiced a lot and can generally solve the super-secret special bonus puzzle eventually, but it takes them forever and ever (more than one minute sometimes).

I am still learning to walk. If I fall down and you act like I should cry about falling down, I will. If you calmly say something like "you should be more careful", I will probably just get up and continue whatever I was doing. Unless I'm tired, in which case I will cry anyway. If I start crying, you should look at that section of the solution.

I like to cruise, which means walking around while holding onto things with my hands. I will pull up on anything conveniently close to me when I want to stand up. My minimum standards for pulling up on something are that it be at least three inches tall and doesn't fall over faster than I can stand up. Pants and legs are fun to pull up on. So are chairs, whether people are sitting in them or not. I might decide to pull up on your chair just before you decide to move it to stand up. I like to silently sneak up on chairs while people are sitting in them, but I don't like it when they somehow don't notice that I am there.

My favorite game is peek-a-boo, particularly around corners. My parents make me fall down from laughing so much by suddenly appearing out of nowhere over and over again. It is the best game ever.

I love reading books. I also like carrying books. I like putting toys on my head. I like banging things together. I like knocking over towers of blocks. I'm starting to like stacking things and putting things in containers.

If you give me paper, I will play with it. I will eat it, I will crumple it, and I might even rip it. If you didn't want me to play with your papers, you shouldn't have left them on the floor near me. If you take them away from me and don't give me a different toy, I will probably cry.

I like to stick new toys in my mouth. Don't give me anything that you don't want me to stick in my mouth (such as your phone). Don't give me anything that my parents would not want me to stick in my mouth (particularly pens and pencils).

I like to babble. Often I while repeat a sound over and over again, just for fun. If you repeat it back to me, it will amuse me. Sometimes I tell stories. Sometimes I tell jokes. I like it when people have a conversation with me. I understand a lot of what people say to me, but they don't seem to understand what I say. This doesn't bother me most of the time.

Diapers:  This is the third bonus puzzle. I am a mostly potty-trained toddler that wears cloth diapers. I like to use the toilet when my diaper is changed. Most of my diapers have multiple pieces and are generally messy. My parents decided how many diapers to bring for me, and will run out if they are used too quickly. You really don't want to solve this puzzle. My parents are experts at it and will manage just fine. If you want to know more about cloth diapers, you can ask my parents. If you really want to change my diaper, talk to a psychologist my parents.

The Naming of Jesse

Picking a name for a child is a difficult task. A person's name is frequently one of the first things that people learn when they meet someone new. It is difficult to change your name. And you have to pick the name before you know anything about your new child.

Mira and I have our own constraints on what names we want. Mira, who had her name mispronounced and misspelled throughout her entire life, wants names that are easy to spell and pronounce. I want names that sound nice (which seems to mean no hard stops, based on the names I like and don't like). We are also following Mira's family's tradition of naming in memory of dead relatives that were important to us (and by naming in memory of them, I mean the first letter has to be the same). Since we are raising our children as Jews, I want them to have Irish middle names in recognition of that part of their heritage (this somewhat conflicts with Mira's requirement that the names be easy to spell and pronounce). And Mira has a rule that we can't use names of any of our exes (which mostly just eliminates one of my favorite names, which is of course Irish, easy to spell, and easy to pronounce).

Operating under those constraints, we chose the name Jesse Liam for our son. Then we chose the Hebrew name Yaakov Lev. Jesse is a biblical name (the father of king David) which means gift. Liam is derived from Wilhelm and roughly means helmet. Yaakov, also a biblical name, has a complex meaning because of the story in which it appears. It means protection according to some sources and basically usurper according to others ("one who grasps"). Lev is the hebrew word for heart. So translating his name into concepts produces "gift of protection, helmet of the heart."

Jesse is for our maternal grandfathers, Jesse and John, Mira's great-uncle Jake, and Mira's great-great-aunt Jeannette. Liam is for my grandmother Love and my great-uncle Liam.

Diaper Changes

I tend to collect a lot of data because I like to analyze data. I have roughly kept track of how much diaper laundry I have done for Jesse, which roughly corresponds to how many diaper changes he has had. Our diaper pail fits approximately 20 diapers, so that is about how many are in each load. On average over the past 9 months, we have had to do 2 loads of diapers per week. The following graph shows about how many diapers Jesse has used per day (with some smoothing), starting in late January:

The data is a little off in some places because of trips and extra diaper laundry when we got new diapers, but I think I mostly corrected for those errors. The large spike near day 100 (which corresponds to early May) was when we started potty training him using elimination communication. The way that worked for us was to basically change his diaper every half hour and put him on a toilet every time. To some degree, this means that the data is scaled differently before and after day 100, because prior to that most diaper changes were with saturated wet diapers, and after that, most diaper changes were with diapers that were barely wet. When we first started EC, his diaper was wet every half hour, which is why there is a huge spike in diaper laundry. Then he started learning to wait for the toilet when that was possible, and the diaper laundry decreased. Additionally, I started using washcloths instead of real diapers because we didn't need much absorbency, and more of them fit in the diaper pail. The downward movement was somewhat exaggerated by some trips in June and July, so I don't think the increase near 150 is real. The increase just past 200 represents moving him back to real diapers all the time as he got better at waiting and started crawling in ways that made the washcloths not work. The decrease past 250 represents progress on toilet training.

Actions have consequences

Throughout our lives, we make decisions which change the rest of our lives. Sometimes it is fairly obvious that a decision will end up being significant, but other times we have no idea how much things will change as a result of what we do. Mira went to the same summer camp for years and eventually ended up as the bus counselor on the bus she rode. The bus route was overcrowded and probably should have been split in half to be safer. She told the camp that she wouldn't come back unless they split the bus, and they didn't. So that summer she ended up working at Old North as a docent instead. Which led to her learning to ring church bells. Which is how we met. Some person I don't know and will probably never meet can claim some credit for me meeting my wife. Life is random like that.

I borrowed a friend's car today to drive to an interview.

When I look back over my life, I can see all kinds of decision paths like that. Some seemingly minor decision sets up a chain of events that eventually changes everything. And I'm sure that there are many more that I am unaware of. A stupid little essay that I wrote in my 7th grade math class because the school board decided that even math classes should have essays was the first step in the process that led to me finishing high school a year early. Which probably changed where I lived at MIT as an undergrad (and possibly even what college I went to). Almost all of my current friends in the Boston area are people that I met either directly or indirectly because I lived at Random. I probably would have met some of them anyway, but who knows? Almost my entire social circle is people that I might have never met if I hadn't written that essay.

While driving north on I-95, I noticed some odd movement in the cars ahead and to the left of me. Then I saw a car that was sideways at the left edge of the road (perpendicular to traffic with wheels down, not on its side).

Some major decisions obviously change our lives. Where we live, where we work, where we go to school all change who we meet and who we spend time with. People tend to agonize over these decisions, as though they are more important. But then someone decides that math classes don't need essays, or that adding a bus is a good idea. And all that careful planning is overwhelmed by the randomness of life.

This seemed like a good time to slow down. Then the sideways car was in front of me. This seemed like a good time to stop. Unfortunately, momentum can't disappear in an instant.

I have been very actively applying for jobs for the past 5 weeks. I'm mostly concentrating on two totally different areas that I think would work well. I know how to connect either of them to my long term plans. I'm not sure which one I like better. One of them probably requires us to leave Boston. There are also some other possibilities that I'm considering which don't clearly connect to my long term plans, but which I can probably manage to make work through creative execution of the secondary backup plan. I'm not actually expecting to have multiple simultaneous job offers, so I will probably take the first one I get, but I might also end up actually getting to make a decision. It's interesting to see how very different the the hiring time scale is for different industries.

The result was a low speed collision between the front right corner of the car I was driving and the driver's side door of the other car. There was a brief period where I thought I would stop in time before I heard and felt the impact.

And then today there's this accident that occurs in front of me and spreads out in a way I don't manage to avoid. When I finished telling the police officer what happened and said "I tried to stop, but I couldn't manage to" he replied with "Yeah, well you're not superman. You clearly weren't at fault." So I guess there's that at least.

But when I thought about it more, I realized that if I had hesitated for 1/4 second, it wouldn't have been a low speed collision. It's likely that the other driver would have been injured. If I had hesitated for a full second, he possibly would have been killed. If I hadn't slowed down at all, then I probably would have been next to the accident by the time his car came across the highway, and it would have been my driver's side door getting hit, and I would have possibly been injured. There was some 2-3 seconds of my life where my actions changed the outcome from me being probably injured to someone else possibly being killed to that person being probably injured to just cars being damaged. Which can be fixed.

Every moment of every day, we are making decisions. Most of the time, we won't know for years which of these decisions will end up mattering. And we never find out about the decisions that would have been important if they had been made differently. But sometimes, we know that a decision mattered right away.

I have this habit of considering what my life would be like if I had done some particular thing differently. It's one of the things I do while I lay awake at night sleeping (I'll explain how that makes sense some other time). But there's a limit to how far I can push things with any kind of certainty. It's easy to work out things that would have prevented something from happening. It's much harder to understand what would have happened if something had been enabled.

The title of this entry is the opening line to the first episode of the TV show "Dollhouse." That show was on track to be my all-time favorite show for the first 1.5 seasons. Then it switched from being a show about some interesting psychology topics into a show about defeating the evil corporate conspiracy. Which is fine, but not nearly as appealing.

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.

Enough Mens, time for some Manus

After spending 8 years doing theoretical astrodynamics (and the last four of those were applying theoretical math that nobody in the Eastern half of the US understands), I needed to spend some time doing something more practical and hands-on. I needed to construct things that could be touched and looked at. There was a brief period where Mira and I considered buying a broken house so that I could rebuild it, but that didn't end up working out. So instead, I had to make do with smaller projects.

Project 1: A hat for Jesse
Mira knits all the time, but I only knit occasionally. In early November, I decided that I wanted to knit a hat for Jesse. Mira had some yarn leftover from a sweater she had made for him, so I started a hat that would match the sweater. Then Mira went into labor. I spent a fair bit of time in the hospital working on the hat, and managed to finish it before we went home, so Jesse was able to wear a matching hat and sweater made by his parents when he left the hospital.

Working on Jesse's hat while holding Jesse in the hospital

The matching hat and sweater on Jesse at about 10 days old

New skills learned: knitting in the round, binding off for a hat

Project 2: Socks for Mira
I told Mira that for her birthday and Chanukah, I would knit her whatever she asked for. She asked for socks, picked out some yarn, and picked out a pattern. I have finished the first sock and I am about halfway down the ankle on the second sock. It turns out that socks have a lot of stitches and therefore take a long time to finish. And this yarn is fairly dark, so I can only work on these when the lighting is good. I don't have any pictures of these yet.

New skills learned: turning a heel with a heel flap, binding off a sock toe

Project 3: A hat for friends' child
Some friends were moving away this fall, and as a going away present, I made a hat for their daughter. This hat was double knit, which is a process of knitting that creates two layers of fabric simultaneously. For some reason people seem to think this is difficult (even Mira has never tried it), but really it just involves having more yarn tangled around your hands. I also designed the pattern. Did you know that every web site that lists hat sizes for toddlers has different numbers for how big their heads are? I kind of guessed what a good size would be based on the range of numbers I could find, put ribbing on the bottom in case it was too big and then made the hat taller in case it was too small (a double knit object is very stretchy, but stretching it in one direction makes it smaller in the other direction). She seems to like her hat, which is nice because two year olds are totally unpredictable and she could have just as easily decided she was unwilling to ever wear it.

One of the nice things about double knitting is that the hat is reversible. It really is like making two hats, but they are attached to each other.

New skills learned: double knitting, knitting pattern design

Project 4: Dresses for Mira

Nursing with the dress on.

Mira and I went to a Bar Mitzvah two weeks ago. Mira was having trouble deciding what she could wear that would be fancy enough while still allowing her to nurse Jesse. So we decided that we would make dresses that would be modified to allow nursing while wearing the dress. Mira helped with the first dress (the black and white one), but then realized that since she is a responsible adult and actually has a job (unlike me), she did not have time to work on sewing. So I finished the first dress and made the second one on my own. The dresses both came out very well and we expect Mira to wear them many more times. We will probably be making more clothing in the future. Sewing in zippers is not nearly as complicated as it seems to be when you read a written description of how to do it. Videos are much better. Also, French seams are awesome.

New skills learned: French seams, zipper installation, sewing in elastic bands, using fusible interfacing, modifying clothes for nursing, adjusting a dress pattern to fit a particular person

Project 5: New shirts for Mira
My sister made nursing turtlenecks for Mira. Winter is coming to an end. Mira needs summer nursing shirts. I will probably make them in May.

Project 6: New Bookcases
This one is still in the planning phase. We have about 800 books. Most of them are in four bookcases in our living room. Mira does not like these bookcases. I like carpentry. I have half-drafted plans for what I want in my head, and hope that I will actually build these bookcases some time this year. I am intending to put doors on the bookcases, so that the small toddler we will have next year can't pull all the books off the shelves. I am also thinking of mounting our television on a bookcase door and putting the TV related electronics (VCR and such) behind the television, with the cords nicely contained. And maybe I'll throw in a coat closet while I'm at it. This is still an imaginary bookcase, so it has all kinds of great features. We'll see what actually happens.