Wednesday, August 22, 2007

Google Does Astronomy

It goes without saying that Google organizes the universe. But in this case, Google is actually organizing the Universe in the latest version of Google Earth, which includes a feature called (duh) Google Sky. It's making quite a splash with reports all over the internet and even on ABC and BBC television news.

What is it? It's basically a planetarium program (requires download and installation) that integrates and displays terabytes of on-line astronomical imagery from various sources including (of course) the Hubble Space Telescope. As for Google Earth's access to features on the Earth, the interface is simple and pretty seamless. Go to a location in Google Earth and click the Sky icon, and the view switches to the view of the sky above that point at this time. You can pan the view with the mouse and zoom with the mouse wheel or other controls... and zoom, and zoom, and zoom. If you select "ultra deep field" in the search field, you can zoom for maybe 12 billion light years worth into this very tiny patch of the deep sky imaged over a million seconds by HST.

It's pretty cool, and if you just want to find and see astronomical objects, it's a great "sky browser." But I do have some complaints. While there is an optional coordinate grid (Control-L), there is no scale indication on the Sky window, and no indication of the horizon, the part of the sky blocked by the Earth, or the ecliptic plane. There's no time of day indication, no time acceleration, and no day light (atmosphere) modeling. It's hard to get a sense of where (and when) you are, and of how much of the sky you are seeing right now (a hemisphere or a tiny patch?). Some features adapted from Google Earth's globe-based model don't work as well in the sky (e.g., zooming to a feature uses a weird dog-leg path). Most of these things are done much better in the freeware Stellarium program, but of course the standalone Stellarium is not linked to anywhere near the amount of imagery that Google Sky can access.

Google Sky inherits many things from Google Earth, including support for layers, favorites, bookmarks, search, etc. The Space Telescope Science Institute for one has made good use of this. You can download STScI's Best of Hubble (watch the video there) and get a tour of some of the greatest HST images and where they are in the sky. I'm sure there will be more add-ons like this from various sources, and that Google Sky will be improved as has Google Earth. Overall it's a fun and educational way to experience the endless beauty of the Universe. And did I mention the price? It's free!

N.B. There are already more tours and overlays available in the Google Earth Gallery. The ability to control the transparency of a selected overlay with the slider control is especially nice for things like the Microwave Sky. This is really a great tool!

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