Last November, I visited Williams Elementary School in Austin to talk to a fifth grade science class about ‘The Moon’s Mysterious Water’. This is a long overdue post to share the material that I prepared for this, and some notes that I penciled down afterwards.
I’ve linked to three files here: the slides from a quick (ten-minute) talk that we started with, a worksheet, and accompanying maps (for which you’ll need to get your own blue/purple dots and gold stars). I should mention that I did not include sources for the images in the slides to avoid visual clutter, but do mean to add a slide later with image credits. The slides (embedded below) outline the story of why water matters, the search for water on the Moon, and the question of comets’ role in delivering water and other ingredients for life to the inner solar system. There are some satisfyingly big ideas to think about in there and some interesting (though I say so myself) tie-backs to elementary school level science, such as the fact that although water exists on our planet as liquid, vapor and solid, this is not the case on all solar system bodies.
The worksheet activity was motivated by the fact that there are currently several teams that are synthesizing data-sets from multiple missions to identify lunar landing sites of scientific interest (along the lines of this study by the Lunar and Planetary Institute), with cold-trapped volatiles at the lunar poles being a major subject of interest. I liked the idea of giving fifth-graders a chance to work with a real planetary science problem, and to explore the Lunar Reconnaissance Orbiter Camera’s gorgeous map of the lunar South Pole. The worksheet is fairly self-explanatory, so give it a go if you like!
Interacting with the fifth-graders was an absolute delight - they were very curious, very endearing and very funny. I have a renewed and boundless respect for the wonderful elementary school teachers who got them all to sit more or less still. I also learned a ton. One major take-away for me (which in retrospect should perhaps have been obvious) was that for this age group, spoken communication was vastly more effective than written. If I were to do this again, I’d spend a little more time talking through the activity step by step. Being possessed of an abundance of enthusiasm, when given a three-page handout, half of the fifth-graders started at the end or the middle, as opposed to the beginning as one might assume. It was also evident that at least this group of eleven-year olds loved to talk (to me, their teachers and each other), which is a great thing - I would rethink how to implement the activity in such a way as to channel this better. Something else to watch out for is to make sure that the students are comfortable with comparing different maps of the same region (“Here’s Shackleton crater on Map 1, where is it on Map 2?”). Once they got it, they seemed to get it very well, but this is a skill that needs to click into place.
Fifth-graders ask lovely questions; I was surprised and pleased by how much in depth we got to talk about things. Someone wanted to know if the Moon was dusty because of all the impacts breaking things up, which was very nail-on-head. One of the questions l liked the most was whether the maria were dark because they were wet - I would never have thought of that myself (lots of open mouths on learning that the dark patches are long-ago lava flows). One of the answers I enjoyed giving the most was how we know that what LCROSS saw was water, and whether there was anything else there - it turns out that fifth-graders really do understand spectroscopy if you explain it to them, which was very satisfying.
All things considered, I think a good time was had by all (at least, I enjoyed myself hugely). If you have any fifth-graders you'd like to engage in conversation about the Moon, please do feel free to use the slides and activity - and of course, I’d love to know how it goes.
It’s been a good week for planetary exploration, with NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) mission and ISRO’s Mars Orbiter Mission (MOM) swinging into orbit around the Red Planet on September 21st and 24th. I have nothing but undiluted delight for both missions, particularly for MOM - India’s first interplanetary mission, wonderfully executed so far. The three other spacecraft in Mars orbit - MRO, Mars Express and Mars Odyssey - are largely interested in the surface of the planet, but MAVEN and MOM will be training their instruments primarily on the thin Martian atmosphere. Some of the Big Questions about Mars are how what was once a warmer, wetter planet became the frozen desert that it is today, and whether it was or remains at all habitable. MOM and MAVEN have different but complementary instruments designed to supply partial answers to those questions. May the Sun shine warm on their solar panels, and may the ground beneath them and the air around them be ever interesting.
I write this because much of the coverage of the two missions has been rather fixated on the fact that one cost considerably less than the other, and I think that this is something of a red herring. That is to say, it is beside the point. If we’re talking costs, the major point to be made is that both missions were accomplished at a miniscule cost. Currently, NASA’s budget hovers at around 0.1 % of the GDP of the United States, and ISRO’s budget is 0.038 % of India’s GDP (the numbers are almost as small when considered as fractions of the national budgets of both countries). Keep in mind that these are the whole budgets of the two agencies - covering not just solar system exploration, but everything they do in terms of keeping watch over our own planet. Let’s be clear about this; at this time, there is very, very little to be gained by snipping away at planetary science budgets or abandoning exploration - and there is the universe to be lost.
To me, the most compelling justification for studying the planets is simply that we live on one. In that light, planetary exploration is a profoundly practical proposition. Every mission allows us to test our grasp of basic physical principles in unfamiliar surroundings. When an observation agrees with our predictions, it strengthens our understanding of the processes that shape all planetary bodies, including our own. Every time we see something that we haven’t seen before or do not understand, we widen the boundaries of what we know a little further. The Solar System, with its strange and varied worlds, resembles a grand experiment awaiting observers. It seems a shame not to observe it.
It has been said that in setting out to discover other planets, it is ultimately our own that we end up discovering, in more ways than one. I think Carl Sagan put it best:
Barely 60 years have passed since the first spacecraft ventured purposefully beyond Earth orbit. Imagine that. Only in the last 60 of the 4,600,000,000 years that our planet has witnessed, have we begun to seriously answer questions that generations before us must have asked of the night sky. Were we to turn our backs on those questions, our lives and imaginations would be infinitely poorer for it.
After a journey of more than ten years, Rosetta is finally at comet 67P/Churyumov-Gerasimenko. Since its launch in 2004, ESA’s comet-chaser has traveled an incredible 6.4 billion kilometers, passing by Earth twice and Mars once, observing asteroids Šteins and Lutetia up close and spending almost three years in deep space hibernation to conserve power before waking up in January 2014. Today, on August 6th, Rosetta caught up with its comet, currently tumbling through space at 55,000 km/h.
67P/Churyumov-Gerasimenko is a periodic comet - that is, it returns to the inner solar system relatively frequently (67P orbits the Sun once every 6.5 years). The ‘P’ in the name stands for periodic; Klim Churyumov and Svetlana Gerasimenko were the two astronomers from Kiev who discovered the comet, the 67th to be identified as periodic. Comets are still mysterious to us in many ways. They travel closer to and further from the Sun than most other objects, and are some of the oldest bodies in the solar system - in them, we can read the origins of the worlds in our neighborhood.
Rosetta will be the first spacecraft to go into orbit around a comet, through a series of looping triangular manoeuvres. Over the next couple of weeks, the instruments on board will map the surface in greater detail, searching for a suitable landing site - because Rosetta carries a three-legged lander, Philae, and this will be the first mission to land on a comet nucleus (not to mention the first to harpoon a comet). The landing is planned for November 2014, and then, Rosetta and Philae will accompany the comet past its closest approach to the Sun in August 2015, continuing to send data back to Earth until December 2015. This is arguably the cutest orbiter-lander duo out there:
As the Sun warms the ices of 67P/Churyumov-Gerasimenko, its coma - the envelope of vapor and dust surrounding the nucleus - will begin to brighten, and escaping tails of dust, gas and ions will curve away from the Sun; these tails can sometimes be millions of kilometers long. Comets also have a tendency to oblige us with stranger sorts of activity, such as by sprouting jets.
Rosetta and Philae have a comprehensive set of instrumentation between them: spectrometers to measure the composition and abundance of different compounds, multiple instruments to study the dust spewed from the surface, a temperature-mapping instrument, high-resolution cameras, a probe and radar to investigate the sub-surface and a host of other tools - almost everything a scientist could wish for.
The first detailed images have been coming in, and they show an odd and rather spectacularly choppy body, the size of a large and irregular mountain, with cliffs, spires, bright, smooth patches and deep shadows. Glimpses that launch a thousand questions; and as Rosetta, Philae, and the science teams on Earth get down to work, the journey is really only just beginning.
JPL Comet Primer: http://rosetta.jpl.nasa.gov/science/comet-primer/what-comet
ESA’s Rosetta Mission Blog: http://blogs.esa.int/rosetta/
Rosetta Fact-sheet: http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_Media_factsheet
The Adventures of Rosetta and Philae (videos):
#RosettaAreWeThereYet – Fabulous fables and tales of tails
#WakeUpRosetta – Once upon a time...
Are we there yet?