Innovation 3806: Astronomers Discover the Most Distant Known Galaxy: Galaxy Seen as It Was Just 700 Million Years after Big Bang, 2013. sciencedaily/releases/2013/10/131023131800.htm “Astronomers … discovered the most distant galaxy ever found. The galaxy is seen as it was just 700 million years after the Big Bang, when the universe was only about 5 percent of its current age of 13.8 billion years. “Astronomers … identified a very distant galaxy candidate using deep optical and infrared images taken by the Hubble Space Telescope. Follow-up observations of this galaxy by the Keck Telescope in Hawaii confirmed its distance. “To measure the distance to these galaxies in a definitive way, astronomers use spectroscopy -- specifically, how much the wavelength of a galaxys light has shifted towards the red-end of the spectrum as it travels from the galaxy to Earth, due to the expansion of the universe. This phenomenon is called red-shift. Since the expansion velocity (redshift) and distances of galaxies are proportional, the red-shift gives astronomers a measure of the distance to galaxies. What makes this galaxy unique, compared to other such discoveries, is the spectroscopic confirmation of its distance … … “Mobasher explained that because light travels at about 186,000 miles per second, when we look at distant objects, we see them as they appeared in the past. The more distant we push these observations, the farther into the past we can see. “By observing a galaxy that far back in time, we can study the earliest formation of galaxies … By comparing properties of galaxies at different distances, we can explore the evolution of galaxies throughout the age of the universe. … “Researchers suspect they may have zeroed in on the era when the universe made its transition from an opaque state in which most of the hydrogen is neutral to a translucent state in which most of the hydrogen is ionized (called the Era of Re-ionization).” “The teams observations showed that z8-GND-5296 is forming stars extremely rapidly – producing each year ~300 times the mass of our sun. By comparison, the Milky Way forms only two to three stars per year. The new distance record-holder lies in the same part of the sky as the previous record-holder … which also happens to have a very high rate of star-formation.”
Posted on: Fri, 25 Oct 2013 15:03:59 +0000
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