Free Astronomy Magazine November-December 2020

NOVEMBER-DECEMBER 2020 SPACE CHRONICLES shining the brightest stars in the galaxy, before fading into obscurity during the year of observations. This time-lapse consists of observa- tions taken over the course of one year, from February 2018 to Febru- ary 2019. “No Earthly fireworks display can compete with this supernova, cap- tured in its fading glory by the Hub- ble Space Telescope,” shared Riess of this new time-lapse of the super- nova explosion in NGC 2525. Super- novae are powerful explosions which mark the end of a star’s life. The type of supernova seen in these images, known as a Type Ia super- nova, originate from a white dwarf in a close binary system accreting material from its companion star. If the white dwarf reaches a critical mass (1.44 times the mass of our Sun), its core becomes hot enough to ignite carbon fusion, triggering a thermonuclear runaway process that fuses large amounts of oxygen and carbon together in a matter of seconds. The energy released tears the star apart in a violent explosion, ejecting matter at speeds up to 6% the speed of light and emitting huge amounts of radiation. Type Ia supernovae consistently reach a peak brightness of 5 billion times brighter than our Sun before fading over time. Because supernovae of this type produce this fixed brightness, they are useful tools for astronomers, P ictured in the background is part of the captivating galaxy NGC 2525 (above). Located nearly 70 million light-years from Earth, this galaxy is part of the constella- tion of Puppis in the southern hemisphere. Together with the Carina and the Vela constellations, it makes up an image of the Argo from ancient greek mythology. On the left, a brilliant supernova is clearly visible in the image. The supernova is formally known as SN2018gv and was first spotted in mid-January 2018. [ESA/Hubble & NASA, A. Riess and the SH0ES team. Ack: Mahdi Zamani]