wonderful universe
Looking back at the year in pictures
— Compiled by MARCELO DE OLIVEIRA SOUZA — In 2021 , as has happened in recent years , we had access to wonderful images of the Universe obtained by the modern and fantastic astronomical observation instruments developed by humanity in these few millennia of civilization . Here , we present a brief chronology with a special selection of the most amazing images released until the month of November 2021 .
February 11 , 2021 :
Hubble uncovers concentration of small black holes
This ancient stellar jewelry box , a globular cluster called NGC 6397 , glitters with the light from hundreds of thousands of stars . Astronomers used the Hubble Space Telescope to gauge the cluster ’ s distance at 7,800 light-years away . NGC 6397 is one of the closest globular clusters to Earth . The cluster ’ s blue stars are near the end of their lives . These stars have used up their hydrogen fuel that makes them shine . Now they are converting helium to energy in
their cores , which fuses at a higher temperature resulting in a blue color . The reddish glow is from red giant stars that have consumed their hydrogen fuel and have expanded in size . The myriad small white objects include stars like our Sun . This image is composed of a series of observations taken from July 2004 to June 2005 with Hubble ’ s Advanced Camera for Surveys . Hubble ’ s Wide Field Camera 3 was used to measure the distance to the cluster .
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