Sonntag, 26.05.2019 19:22 Uhr

Wide View of the Evolving Universe assembled by Hubble

Verantwortlicher Autor: Carlo Marino Rome , 04.05.2019, 21:54 Uhr
Nachricht/Bericht: +++ Internet und Technik +++ Bericht 3549x gelesen

Rome [ENA] In 1995, astronomers decided to use the Hubble Space Telescope to conduct an adventurous and daring experiment to address the puzzle: How far is far? And, how do you know when you get there? For 10 consecutive days, Hubble stared at one tiny, seemingly empty patch of sky for 1 million seconds. The gamble of precious telescope time brought enormous benefits for knowledge .

Hubble captured the faint glow of myriad never-before-seen galaxies. Many of the galaxies are so far away it has taken billions of years for their light to reach the Earth. Therefore, the view is like have a prospect of a "time corridor," where galaxies can be seen as they looked billions of years ago. In this way, Hubble became astronomy's ultimate time machine. The resulting landmark image is called the Hubble Deep Field. At the time, the image won the gold medal for being the farthest peek into the universe ever made by human beings. Its enormous success encouraged astronomers to pursue a series of Hubble deep-field surveys. The subsequent surveys discovered more galaxies at greater distance from

Earth, thanks to new cameras installed on Hubble during astronauts servicing missions. The cameras increased the telescope's power to look even deeper into the universe. These surveys offered astronomers an enormous scrapbook of images, showing how, following the big bang, galaxies built themselves up over time to become the large, majestic assemblages seen today in the nearby universe. They stretch back through 13.3 billion years of time to just 500 million years after the universe's birth in the big bang. Among the most notable deep-field surveys are the Great Observatories Origins Deep Survey (GOODS), in 2003; the Hubble Ultra Deep Field (HUDF), in 2004; and the eXtreme Deep Field (XDF), in 2012.

At the moment, astronomers are releasing a new deep-field image by weaving together exposures from several of these previous galaxy "fishing expeditions." Their efforts have produced the largest, most comprehensive “history book” of galaxies in the universe. The snapshot, a combination of nearly 7,500 separate Hubble exposures, represents 16 years' worth of observations. The ambitious attempt is called the Hubble Legacy Field. The new view contains about 30 times as many galaxies as in the HUDF. The wavelength range stretches from ultraviolet to near-infrared light, capturing all the features of galaxy assembly over time.The image mosaic presents a wide picture of the distant universe and contains roughly 265,000 galaxies.

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