NASA recently observed an impossibly fast jet being propelled at nearly the speed of light, and now, the Hubble Space Telescope has imaged a mesmerizing barred spiral galaxy 214 million light-years away. Called NGC 6956, this galaxy can be found in the constellation Delphinus and has many Cepheid variable stars, which are clusters that brighten and dim at regular periods.
The period of Cepheid variable stars is essentially a function of their brightness, enabling scientists to measure how bright they appear from Earth and compare it to their actual brightness to calculate their distance. This means that these stars are extremely useful in determining the distance of cosmic objects, which has long been one of the most elusive pieces of information to measure for extra-galactic objects.
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This galaxy also contains a Type Ia supernova, which is the explosion of a white dwarf star that was gradually accreting matter from a companion star. Like Cepheid variable stars, the brightness of these types of supernovae and how fast they dim over time enables scientists to calculate their distance. Scientists can use the measurements gleaned from Cepheid variable stars and Type Ia supernovae to refine our understanding of the rate of expansion of the universe,” said NASA.
