Searching the Internet has always been dicey, given the wide range of sites you’re likely to pull up on any topic, and the varying degrees of quality each may bring. Google has done good work in restricting Web results — its ‘site-specific search,’ for example, allows you to search within a universe of sites related to a particular topic.
Now the company has gone one better with a new engine called Google Scholar, a test version of which is available.
The beauty of Google Scholar is that your search is limited to journal articles, books, preprints, technical reports and theses, the kind of material serious researchers need to uncover without having to sift out all the chaff. As this article in Nature makes clear, the new service does a fine job at finding the relevant articles on your topic, using variations on the familiar Google algorithms that study the linking that takes place between Web pages and offer a key to their utility.
But instead of studying links to other pages, Google Scholar uses citations, creating indices that offer still more valuable clues about which paper may be most useful. Suddenly the searcher is in a peer-reviewed realm, much of which as been made available to Google through CrossRef Search, a pilot engine that takes searchers to the publishers’ sites, where they can receive an abstract or, if they are subscribers to the content, the full text.
And as the Nature story indicates, there’s also an interesting twist: “Google Scholar has a subversive feature…Each hit also links to all the free versions of the article it has found saved on other sites, for example on personal home pages, elsewhere on the Internet.” Finding what you need is going to become a lot easier as this service matures.
Try conventional Google on a search for information about Clifford Singer’s ‘pellet propulsion’ concepts. Singer discussed firing a stream of pellets from an accelerator to drive a space probe, replacing the stream of photons that might be used to push a lightsail. The pellets would be vaporized on reaching the vehicle, creating a plasma exhaust. A key advantage: you avoid the collimation problems you get with a laser or particle beam, which spread at interstellar distances.
Using ‘singer,”pellet’ and ‘propulsion’ as search terms, I get 98 hits on regular Google, about ten of them high quality. Google Scholar gives me 18, but leads the citations off with the key one: Singer’s 1980 paper in JBIS called “Interstellar Propulsion Using a Pellet Stream for Momentum Transfer.” Even more useful is the link that comes with that top citation, offering a quick Web search for places where the paper is cited. Thus I can go immediately to papers that discuss my topic. Other top-rated items are also useful, and include Dana Andrews’ seminal “Interstellar Transportation Using Today’s Physics.”
We still face the problem that so many key resources, especially older ones, are not yet available on the Web (and it continues to boggle this mind that a source like the Journal of the British Interplanetary Society still offers no online bibliography). But Google Scholar is emphatically a step in the right direction, one that will be welcome in the toolbox of any serious researcher.