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The Hubble Space Telescope recently captured images of an exploding star 70 million light-years away. The event was recorded as part of an ongoing program to measure the expansion rate of the universe in order to better understand its age. For a moment, the explosion outshined its entire host galaxy and the resulting energy was 'equal to the radiance of 5 billion Suns.'
NASA has assembled its images from the Hubble Space Telescope to create a new time-lapse sequence, seen below. The supernova explosion took place in the spiral galaxy NGC 2525. In February 2018, Hubble began its observation of SN2018gv after a Japanese amateur astronomer, Koichi Itagaki, first detected it in mid-January. The supernova has been used to help precisely the expansion rate of the universe, which is itself critical to our understanding of the universe.
The time-lapse sequence above spanned nearly a year, with the supernova first appearing 'as a blazing star located on the galaxy's outer edge. It initially outshines the brightest stars in the galaxy before fading out of sight.'
Nobel Laureate Adam Riess of the Space Telescope Science Institute (STScI) and John Hopkins University says, 'No earthly fireworks display can compete with this supernova, captured in its fading glory by the Hubble Space Telescope.' Riess is the leader of the High-z Supernova Search Team and the Supernovae H0 for the Equation of State (SH0ES) Team.
The NASA Hubble Site news release continues, 'The type of supernova seen in this sequence originated from a burned-out star—a white dwarf located in a close binary system—that is accreting material from its companion star. When the white dwarf reaches a critical mass, its core becomes hot enough to ignite nuclear fusion, turning it into a giant atomic bomb. This thermonuclear runaway process tears the dwarf apart. The opulence is short-lived as the fireball fades away.' SN2018gv is a Type Ia supernova. You can learn more about supernovae and the characteristics of each type in this article from BBC's Sky at Night.
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| NASA, ESA, and A. Riess (STScI/JHU) and the SH0ES team Acknowledgment: M. Zamani (ESA/Hubble) |
Supernovae like SN2018gv peak at the same brightness, which allows them to act a type of standard, 'standard candles.' With the actual peak brightness known, scientists can determine the distances of host galaxies by comparing visible brightness. With this information, it is then possible to measure the expansion rate of the universe itself. You can learn more about how Hubble has aided in our understanding of the universe's expansion rate in this article.