Course: The Science of the Solar System
School: Caltech (Coursera)
Instructors: Mike Brown
This course is a scientific exploration of our solar system. You will learn both what we know about the solar system around us but also how we have been using the tools of science to learn the things that we know. You will get to use some of the tools yourself.… we will focus our examination of the solar system on four main topics: (1) Where is there water on Mars? (2) What is inside of a giant planet? (3) How can we use the smallest bodies in the solar system to answer the biggest questions? (4) Where might we look for life?
To answer these questions we will learn about details of atmospheric chemistry and dynamics, planetary interiors and magnetism, the geological history of planets, spacecraft exploration, telescopic observations of planets around other stars, spectroscopic determinations of composition, biochemistry of water- and non-water based life, and many more. In short, we’ll learn about the whole solar system and about planets in other systems besides ours.
[Addendum: This course has been converted to the new Coursera platform; some content may have changed, and the experience may be very different from that described here]
Some courses, I just take. Some courses, I love. Like this one.
Mike Brown killed Pluto, and he’s proud of it, and he explains why towards the end of this course, just before he explains how to look for signs of life in the universe.
But we started out a lot closer – right next door, with Mars. And we heard stories, going back to Galileo and Percival Lowell and how our view of Mars has changed from the time of ancient Greece, and with plenty of droll, understated humor (like – and this is a direct quote from world-class astronomer with the chops to get Pluto kicked out of the planet club: “And as far as I can tell, they were looking at the region with the sea monster and the porpoise, oh, and the stingray. And yet, we think Mars has no oceans”). So by the time the math and physics came in, I was already hooked. Then we went to Mars, and it was too late to turn back.
You see, this ran concurrently with the real-life CalTech course, and while those kids, and some of the MOOC students, didn’t need any coddling, the rest of us needed all we could get. Because, of course, this is a science class. One of my favorite moments came in the middle of Week 1, when Mike said those immortal words: “As you might remember from orbital mechanics….” Other favorite lines:
What does it take for something to be really old? Nothing. Nothing can have happened in something like 4 billion years.Usually when we think about quantum mechanical states – if you ever think about quantum mechanical states – …This is a differential equation, but its about the simplest differential equation in the world.It’s a very strange thing. Why you might ask? Why: because quantum mechanics.
It’s tough to design a MOOC that will appeal to both scientists (and there were lots of past, present, and future scientists in the course) and the rest of us, but this managed with a multi-leveled approach. The MOOC quizzes were more conceptual than quantitative (hey, you’d be surprised how hard conceptual can be), but if you felt that was not rigorous enough, the CalTech homework was available (right over there, see?), complete with designated discussion forums (which, I see, when unused after W2… I mean, CalTech kids took orbital mechanics and differential equations in kindergarten, they aren’t fooling around). Also available was the CalTech students’ public blog. I took a look at these things early on, but then I went back to my “explain it to me like I’m six” questions. Still, it’s great the more detailed material is available for those who dare.
One of the best features was this mix of Those Who Understand and Those Who Go “Huh?” There were lots of people able to help the rest of us who were welcomed to ask basic questions. When there’s a balance of people with questions and people with answers, it’s a synergystic thing that really cooks, and it’s one of the magical things that MOOCs can do. It’s a tough balance to draw: you have to attract people who have answers (marquee-value names like Mike Brown and CalTech help with that) without scaring away those who not only don’t remember orbital mechanics, they aren’t really sure what it is. The
teaser video (oops, gone) might help with that, though I think he’d be better off to run Lecture 3:10: “I love holding this little piece of iron meteorite in my hand, and showing it to people, and explaining to them that this, this is the core of a tiny mini planet that was forming back at the very beginning of the solar system, that sadly had an impact which catastrophically shattered it into pieces, but then let parts of it fall onto the earth.” How could anyone resist?
I can’t say I did well; I started out pretty strong, but there was just too much stuff for me to keep straight. But I did come away with a basic understanding of about half of it, and glimpses of the rest. And some wonderful extras that weren’t in the syllabus, but were wonderful nonetheless:
Google Mars. As much as I hate Google Earth, that’s how much I love Google Mars. Except, ok, I don’t love Google Mars so much as I love the idea of Google Mars. We used jmars a lot more during the course, because it offers different types of maps, but it’s still cool that there is such a thing as Google Mars.
Blackbody radiation and emission spectroscopy sort of makes sense to me now. It’s probably the most useful thing for me to understand at my (very low) level, since it comes up over and over again, and I’ve always found it confusing. Ok, this was in the syllabus.
Have you ever looked up the etymology of “adiabat” (coined in 1838 by Scottish engineer/physicist John Rankine from Greek adiabatos “not to be passed through,” from “α-” “not” + διὰ [“through”] + βαῖνειν [“passable”] = not +passable + through)? If I can’t handle the physics, at least I can play with words. I can’t say I’m able to connect my feeble understanding of the adiabat as it applies to what’s going on inside Jupiter, and the more frequently given example of clouds smacking into mountains and raining on one side, but maybe another MOOC.
And speaking of Jupiter’s interior: degenerate matter. Cool.
The Cavendish experiment was first performed in 1797, and here I am just finding out about it now. But it’s awesome; I still can’t believe gravity works in a way you can see, with stuff you put together in your basement. It seems to be one of those things every high school student does for extra credit, so there are lots of examples on Youtube.
5678. That is: 56 = 7 * 8. WHY DID NO ONE EVER TELL ME THIS BEFORE??!?!
Hematitic Concretions would be a great band name.
One of the nice touches was guest lecturers, including Mike’s fellow CalTech professors Bethany Ehlmann, John Grotzinger (who talked about these pictures of Mars sent back by Curiosity Rover), and Heather Knutson, rising-star (pun intended) gradTAs Danielle Piskorz and Mike Wong, and JPL Deputy Chief Scientist Kevin Hand. We took a virtual trip to Hawaii to check out the Subaru telescope. While that was taped a while ago, by chance Mike was scheduled for time on the Keck telescope on the same Hawaiian mountain during the course’s run, so he answered on-the-spot questions, even as he recovered from a bout of food poisoning.
If you have the slightest interest in solar system astronomy, or any science really, I highly recommend this. I found it to be difficult, but not impossible; I think I even “passed”, much to my surprise. Lots of work, and I put in a great deal of time, far more than the 4-6 hours/week estimated in the introductory blurb. I was lucky I’d just taken two chem courses and three earth science courses, so the only piece I was really missing was physics. If you don’t have any science background, try it anyway – MOOCs don’t have to be about grades, you know. The lectures are great, you’ll probably pick up more than you expect, and you might find yourself wanting to know more. That’s how they rope us in, you see, the scientists, dangling these bright shiny things in front of us…
In fact, that’s become for me the sign of a great course: does it leave me wanting more? This one does. I really, really need to take some very basic physics. Unfortunately, that involves calculus, which I’ve been thwacking away at for a couple of years now, but maybe a more concrete approach would help. I’d love to do this course again, when I have more of the background, and pick up all the things I missed. And enjoy the lectures again. Just for the fun of it.