The lazily winding spiral arms of the spectacular galaxy NGC 976 fill the frame of this image from the NASAEstablished in 1958, the National Aeronautics and Space Administration (NASA) is an independent agency of the United States Federal Government that succeeded the National Advisory Committee for Aeronautics (NACA). It is responsible for the civilian space program, as well as aeronautics and aerospace research. It’s vision is “To discover and expand knowledge for the benefit of humanity.””>NASA/ESA Hubble Space TelescopeThe Hubble Space Telescope (often referred to as Hubble or HST) is one of NASA’s Great Observatories and was launched into low Earth orbit in 1990. It is one of the largest and most versatile space telescopes in use and features a 2.4-meter mirror and four main instruments that observe in the ultraviolet, visible, and near-infrared regions of the electromagnetic spectrum. It was named after astronomer Edwin Hubble.”>Hubble Space Telescope. This spiral galaxy lies around 150 million light-years from the Milky WayThe Milky Way is the galaxy that contains the Earth, and is named for its appearance from Earth. It is a barred spiral galaxy that contains an estimated 100-400 billion stars and has a diameter between 150,000 and 200,000 light-years.”>Milky Way in the constellation Aries. Despite its tranquil appearance, NGC 976 has played host to one of the most violent astronomical phenomena known — a supernova explosion. These cataclysmicly violent events take place at the end of the lives of massive stars, and can outshine entire galaxies for a short period. While supernovae mark the deaths of massive stars, they are also responsible for the creation of heavy elements that are incorporated into later generations of stars and planets.
Supernovae are also a useful aid for astronomers who measure the distances to faraway galaxies. The amount of energy thrown out into space by supernova explosions is very uniform, allowing astronomers to estimate their distances from how bright they appear to be when viewed from Earth. This image — which was created using data from Hubble’s Wide Field Camera 3 — comes from a large collection of Hubble observations of nearby galaxies which host supernovae as well as a pulsating class of stars known as Cepheid variables. Both Cepheids and supernovae are used to measure astronomical distances, and galaxies containing both objects provide useful natural laboratories where the two methods can be calibrated against one another.