#astronomy Hubble takes the measure of a close-by globular cluster – Astronomy Now

October 13, 2019 - Comment

Utilizing primary trigonometry, astronomers can immediately calculate the distances to close by stars by measuring the tiny shift in place that happens as Earth sweeps from one facet of its orbit to the opposite. However what about globular clusters, the large star swarms that orbit the core of the Milky Approach? They’re usually too distant


Utilizing primary trigonometry, astronomers can immediately calculate the distances to close by stars by measuring the tiny shift in place that happens as Earth sweeps from one facet of its orbit to the opposite. However what about globular clusters, the large star swarms that orbit the core of the Milky Approach? They’re usually too distant to measure the tiny angles wanted to make the calculations. As an alternative, astronomers had been lengthy compelled to estimate distances based mostly on stellar evolution principle and the way the brightness and hues of stars in a globular cluster differed from related close by suns. However final 12 months, the Hubble House Telescope managed to immediately measure the gap to NGC 6397, one of many nearest globulars to Earth, to an accuracy of simply three p.c. The reply? 7,800 gentle years. The cluster apparently fashioned some 13.four billion years in the past, shortly after the large bang.

NGC 8397, one of many closest globular clusters. Picture: Hubble House Telescope



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