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Wednesday, December 12, 2007

 

Science Literacy, Saturns Rings and Fying Saucer Moons

Image Credit NASA/JPL/Space Science Institute.

Science literacy has occupied my mind much lately. In a complex world where much of what we do is influenced by science, and in democracies where people are expected to have some form of input into issues as diverse as stem cell therapy and global warming, science literacy is of utmost importance.

By Science literacy I don’t mean just the ability to reel of a list of scientific facts, but a broad appreciation of how science works, how we build up scientific knowledge and an understanding of how to find facts and try and understand their context.

This was brought home to me by two things this week, the report that Pan and Atlas, Moons of Saturn, are shaped like disks, and a truly awful Creationist video about the Universe and the solar system. There is only one thing to say about that video. “The Stupid, it Burns!” The fact that I saw it on the same day as I saw the latest evidence for our leading model of ring formation is sheer irony.

I dearly love astronomy and space science, and I hate seeing it violated in this way, but sadly, there is just so much nonsense in that video that I would be here until Christmas writing about it’s gross errors. But I will take one statement from the video and use it to illustrate a little of what I mean about science literacy.

"Scientists have no answer for why some planets have rings."

First things first. There is a logical leap here which should be pretty obvious (well apart from the fact that there is no reason at all why evolutionary biology, which explains the origins of diversity of biological organisms, should have anything to do with star and planet formation). The fact that scientists cannot currently explain a phenomenon does not mean we will never be able to explain a phenomenon. Science is not a list of established facts, but a dynamic process of investigating the natural world (the number of newspaper articles which start “Scientists have just discovered …” should be a clue to almost everyone that scientists don’t sit around doling out established facts. Scientists investigate things, for centuries no one had a clue how the Sun worked, but then we worked out atomic fusion. Well, that’s the logic bit over.

Now, back to science literacy. The interweb is a wonderful thing. With the advent of Google I can type in the following string in the search box “formation Saturn’s Rings” (you can type “origin Saturn’s Rings” too, it gives you a somewhat different and much better list, try both and see). Top of the list is this page which says under Formation and Composition of the rings

Scientists once thought that the rings were formed at the same time, as the planets when they coalescing out of swirling clouds of interstellar gas 4.8 billion years ago. Under this model, remnants of material within the Roche limit could not condense and would become rings. However, in recent years this idea seems to be flawed. The rings appear to be young, perhaps only hundreds of millions of years old. One of the clues to this theory is that the rings are bright. As Saturn travels though space, the rings accumulate dust particles that have been darkened from solar radiation. If the rings were old, they should appear dark. Another theory suggests that perhaps a comet few too close to Saturn and tidal forces broke it into pieces similar to comet Shoemaker-Levy/9. Perhaps one of Saturn's moons was struck by an asteroid smashing it into the bits and pieces that form the rings. Hopefully the Cassini spacecraft can answer some of these questions.

So we can see that there are at least three possible explanations for the existence of the rings, one of which appears to be unlikely based on evidence. So much for “Scientists have no explanation”.

Lets look at the second hit, from Berkley, it’s a problem set based around the idea of tidal disruption (Tidal disruption seems to be ruled out). Hang on, what’s going on here, we have three explanations, and two of those don’t seem to be supported? Oh No! We are testing our ideas with evidence! Nine Planets (hit number 3) doesn’t give any more evidence than the first two sites. The next hit is an academic abstract, the next is what appears to be a kook site, and then a kids site.

So, after a page of pages (sorry), we haven’t learned to much about Saturns rings origins, except that the creationist claim is obviously wrong (“origin Saturn’s rings” gets you into some real data sooner, at hits 5, 6 and 8 making sure you have the right search sting is critical to searching, also try Wikipedia).

Hit 11 on the “formation Saturn’s Rings” search comes up with the flying saucer Moons (pictured above). As well as being seriously cool, these Moons give some insight into ring formation (although you won’t know it from the above article, see this one for how the shapes of the Moon’s support the shattered moonlet theory, see also here, and here from the “origin Saturn’s rings” search.

After your search, you will be somewhat dazed and confused. However, even the most science illiterate person will realize that the statement “Scientists have no answer for why some planets have rings” is wrong. Assembling the fragments you get from the search into a coherent picture is harder. If you only base your knowledge on the web searches, you may not develop a sense of our understanding of the formation of the rings, but seem to be confronted with a series of disconnected facts. Getting the sense that our leading theory is the "Shattered Moonlet" theory, and that the Pan and Atlas images support that theory is much harder.

Learning how to synthesise these apparent disparate facts into a clearer picture is the role for science literacy. Heck, even learning that you need to do searches under different search strings and read more than one or two web sites (and how to recognize untrustworthy websites) is part of science literacy. How do we achieve this? Well, that’s another post for another day.

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