Vince_Condella's Blog

No, this blog isn't about a certain candy bar.  But they do taste good.  Mmmmmm.  Instead, we're talking about the Milky Way Galaxy, the collection of stars in a spiral where our solar system resides.  When you look out at the night sky, every star you see resides within our Milky Way galaxy.

It is estimated that our galaxy contains 300 billion stars in a disk-shaped spiral with a central bulge.  The diameter of the Milky Way is estimated to be 100,000 light years, and our Sun and solar system is located in one of the spiral arms about two-thirds of the way out from the center.  It takes our Sun about 200 million years to circle the galaxy just once.

Note: a light-year is the distance something can travel in one year when moving at the speed of light, 186,000 miles per second.  A light year is 5,865,696,000,000 miles!

The mind-blowing thing about all of those numbers is the fact that our Milky Way is just one of approximately 500 billion galaxies in the universe.  I know, I know.  You're thinking "How do they know that?  Are they just making numbers up out of thin air?"  These estimates by astronomers are based on surveys of the universe by the Hubble Space Telescope and many other orbiting and ground-based instruments.

A recent anouncement from the American Astronomical Society meeting in St. Louis reveals that a local scientist has helped define a new look for our galaxy.  Professor Bob Benjamin from the Physics Department at the University of Wisconsin-Whitewater used data from the Spitzer Infrared Space Telescope to determine the true look of our galaxy.

Artist drawing of the Spitzer Infrared Space Telescope.

Infrared telescopes don't see in visible light like our eyes.  They can see through the interstellar dust that obscures our view of many of the stars in the Milky Way.  Professor Benjamin and others used 800,000 snapshots of about 110 million stars in the Milky Way to reveal our Milky Way as a barred spiral arm galaxy similar in appearance to others like the one pictured below.

It is believed that our Milky Way has two main spiral arms.  The photo above is a similar-shaped galaxy called NGC 1300, about 69 million light-years away.

The recent discovery of the new two-armed look of our galaxy is significant because it differs from previous beliefs about the structure of the Milky Way.  Also, it is pretty difficult to get a picture of the galaxy from the outside when the view is from the inside.  But through clever and exhausting use of infrared data, a local UW-Whitewater professor and others have achieved quite a unique view of our home galaxy.