2012-10-03. NASA's Infrared Observatory Measures Expansion of Universe |

posted Oct 3, 2012, 12:14 PM by Alan Gould

NASA RELEASE : 12-343. Relevant to GSS A Changing Cosmos chapter 4. Excerpt:  …Astronomers using NASA's Spitzer Space Telescope have announced the most precise measurement yet of the Hubble constant, or the rate at which our universe is stretching apart. …It improves by a factor of 3 on a similar, seminal study from the Hubble telescope and brings the uncertainty down to 3 percent, a giant leap in accuracy for cosmological measurements.  …Glenn Wahlgren, Spitzer program scientist … said infrared vision, which sees through dust to provide better views of variable stars called cepheids, enabled Spitzer to improve on past measurements of the Hubble constant. ...Spitzer observed 10 cepheids in our own Milky Way galaxy and 80 in a nearby neighboring galaxy called the Large Magellanic Cloud. … "Just over a decade ago, using the words 'precision' and 'cosmology' in the same sentence was not possible, and the size and age of the universe was not known to better than a factor of two," said Freedman. "Now we are talking about accuracies of a few percent." … Read the full article: http://www.nasa.gov/home/hqnews/2012/oct/HQ_12-343_Spitzer_Cepheid.html