27 January 2011

In Honor of John Huchra

John Huchra, a veteran astronomer based at the Harvard-Smithsonian Center for Astrophysics (CfA), unexpectedly died last fall at the age of 61.  To honor his legacy, his friends and colleagues have now set up on the interactive website WorldWide Telescope a special tour titled, appropriately enough, "John Huchra's Universe."  I highly recommend taking a look.  To get instructions on how to access the tour on the WorldWide Telescope (or where to go to view a non-interactive version on YouTube), click here.  

Watching the program brought back many memories for me, for John provided me with one of my first "scoops" in science journalism.  In 1985 he and his collaborator Margaret Geller allowed me to get an early peek at their latest finding: a map of galaxy redshifts, taken through a narrow slice of the sky, out to more than half a billion light-years.  It showed that galaxies are not smoothly distributed through the universe but instead congregate to form gigantic, nested bubblesa cosmic foam.  Inside the bubbles were equally huge voids.  This wasn't a celestial architecture that anyone was expecting.  It was big news. I wrote a story on it for Science Digest, a report timed to coordinate with John and Margaret's discovery announcement at the 1986 annual meeting of the American Astronomical Society. 

The original 1986 CfA map of galaxy distributions

Theorists now believe that the bubblelike structures were forged when pressure waves moved through the early universe's hot primordial plasma, creating regions of compressed and rarefied matter.  This led to galaxies forming predominantly in the areas of compression and the less dense voids enlarging over time and remaining relatively empty.  Geller likened the distribution to a "kitchen sink full of soapsuds." 

Over the succeeding decades, astronomers have enlarged this map extensively.  Here's a look at the Two-Degree Field Galaxy Redshift Survey carried out in the 1990s that extends out to two billion light-years:

Each point in the image represents a galaxy—tens of thousands overall in two slices of the sky

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