How many links does it take to go from one part of science to another? To be a little more concrete, how many steps do you have to take to get from a paper on exercise physiology to a paper on black holes?
This was the question my son and I discussed some Sunday night. It arose because I'd suggested PubMed as a good place for him to get information about exercise (what's good, or not, for you). PubMet is a great resource. At least the abstract of every paper (within some range of biology) is available there. If you want to know how much protein is too much, and just why that's too much (my last use of it), they've got the research. Now, PubMed works great for me. I go in, find what I'm looking for, and get out.
My son, however, has the problem that I do with research in my field. Namely, in reading the first paper on a topic, he sees how it references several others that are also very interesting. So read one, find 3 more that have to be read. (I'm being conservative here.) Read those three, and each shows you three more that are also very interesting. So now we have nine to read. And so on.
He mentioned that he could start out reading about exercise physiology and wind up with a paper on black holes. I agreed (he is my son after all) and started wondering about how many steps it would take. The only thing which keeps me from having the same problem is that I reserve this inclination for my professional field. But I do approach satisfying it there. (Eventually, namely after the first couple thousand papers I read, the interesting papers I found from reading one paper were papers I'd already read.)
My guess is maybe 20 steps between exercise physiology and black holes. I know that it's only 1 step between turkey vultures and sea ice. Keep in mind, turkey vultures are not polar creatures, and do not like it to be especially cold. You don't find them closer to the Arctic than southern Canada. But I was involved in a project, which definitely did need knowledge of sea ice, and that project was then used by people studying turkey vultures. This is part of what I call the range and unity of science. I also know, though never wrote it up for the blog, that it's only 1 step between trying to observe gravitational waves (LIGO) and predicting waves on the ocean. My source being one of the LIGO people asking for information about the ocean's waves.
Might be only two steps between exercise physiology and black holes. 1) Exercise physiology paper looking at swimming or kayaking in the ocean, and how waves affect that. 2) waves and LIGO (I'm sure some LIGO paper cites both waves and black holes at this point).
Since I've put forward two unlikely connections, each only 1 step, I'll turn the table over to you all. Can you make a connection -- in the professional literature, no fair using something like 'Guide to all science' -- between exercise physiology and black holes? How short a chain can you make it? Feel free to change the targets to other things you're interested in (kumquats and functional MRI imaging of the brain?).