Six Characters in Search of a Blogger

10.4 Weighing the Galaxies: Professor Alyssa Goodman

Thanks to this week’s Special Guest Author, Iain B.  (my husband)

The Tarantula Nebula, NASA/JPL, Spitzer Space Telescope

Photo: The Tarantula Nebula, NASA/JPL, Spitzer Space Telescope

So far we’ve talked about how the heavens were first discovered, how the universe is catalogued, and research into fundamental particles and energy.  But how do the very small subatomic particles combine to become very large galaxies, their stars, planets, and ultimately you and I?

As well as the individual stars which are easily viewed by the naked eye or with small telescopes, there are much dimmer areas of the sky where new stars are continually being born.  These are huge clouds of inter-stellar dust (known as nebula) where individual particles of matter coalesce into stars, formed under tremendous temperatures and pressures caused as they collect under the force of their own gravity.

This, the origin of star formation, is the big question that Professor Alyssa Goodman of Harvard University, as part of the COMPLETE project, has made a career of studying–by mapping the sky on the very large scales only possible with the Spitzer Space Telescope.  Whereas the Hubble telescope gets all the glory for its visually stunning astrophotography, the Spitzer does its scientific measuring in infra-red (or ‘heat’ as we more commonly refer to that area of the spectrum) across much larger areas of the sky.

Of course, trying to image vast areas of the sky all at once generates a huge amount of data, and one of the areas in which Professor Goodman has made real advances is the ability to process that data down to something much more meaningful and scientifically relevant than just the raw numbers.  For example, by looking at radiated heat rather visible light, Spitzer can zoom in to look deep inside the dust clouds and provide a much more accurate assessment of the amount of matter involved in star formation. And as another trick, by “zooming out” on the collected data and looking at temperatures across the sky (essentially, averaging out the high and low readings) Professor Goodman and her colleagues in COMPLETE can actually use the aggregated data to “weigh” whole galaxies.

And science doesn’t get much bigger than weighing galaxies.

To hear Professor Goodman talk more about her work and its impact, tune in to a Live webcast at 7:30 p.m. Eastern Standard Time  on Thursday 15th Jan, “The WorldWide Telescope: Astronomy of the Future”


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