Spiral galaxy NGC 4151, aka The Eye of Sauron. Composite of x-rays (in blue), visual light (in yellow), and radio waves (in red). The yellow is where star formation has recently occurred.

Spiral galaxy NGC 4151 has a supermassive black hole in its center (shown here in white) that's actively growing. Its nickname is "The Eye of Sauron," and we promise we didn't choose this image just for the "Lord of the Rings" reference.

X-ray: NASA/CXC/CfA/J. Wang et al.; Optical: Isaac Newton Group of Telescopes, La Palma/Jacobus Kapteyn Telescope; Radio: NSF/NRAO/VLA

What We Learn from Supernovae

British pop band Oasis' hit song "Champagne Supernova" is now fodder for retro radio stations -- or the occasional ringtone. But when it was first released in 1995, it burned up the charts, going on to sell 3.9 million copies [source: Gundersen].

Even with such a record of success, "Champagne Supernova" pales in comparison to actual supernova SNLS-03C3bb. Astronomers discovered the supernova in 2006 and promptly nicknamed it the "champagne" supernova because it rocked their expectations (and what better way to celebrate than with a little Britpop?). The supernova equaled 2 solar masses before it exploded. This far exceeded the 1.4 solar masses -- the Chandrekhar limit -- that astronomers would have expected [source: CBC, Jeffery].

So why celebrate the spotting of a really, really gigantic star's death? Not only was SNLS-03C3bb a game-changer, but understanding how different stars die allows scientists to predict how future supernovae will impact the rest of the universe.

Type Ia supernovae completely destroy the core of a star, but the other three types leave a super-dense core behind. When a Type Ib, Type Ic or Type II supernova results from a star with an inner core of less than 3 solar masses, it creates a neutron star with a core about as dense as an atom's nucleus and a powerful magnetic field. If its magnetic field creates lighthouse-style beams of radiation that flash toward Earth as the star rotates, it's called a pulsar.

When a star with a core equal to 3 solar masses or more explodes, the aftermath of its explosion can result in a black hole. Scientists hypothesize that black holes form when gravity causes a star's compressed inner core to continually sink into itself. A black hole has such a powerful gravitational force that it can drag surrounding matter -- even planets, stars and light itself -- into its maw [source: NASA]. You can learn more about them in How Black Holes Work.

All of their powers of destruction aside, a lot of good can come of a supernova. By tracking the demise of particular stars, scientists have uncovered ancient astronomical events and predicted future changes in the universe [source: NASA]. And by using Type Ia supernovae as standard candles, researchers have been able to map entire galaxies' distances from us and determine that the universe is expanding ever more rapidly [source: Cal Tech].

But stars leave more than an electromagnetic signature behind. When a star explodes, it produces cosmic debris and dust [source: NASA]. Type Ia supernovae are thought to be responsible for the large amount of iron in the universe. And all of the elements in the universe that are heavier than iron, from cobalt to roentgenium, are thought to be created during core collapse supernovae explosions. After millions of years, these remnants comingle with space gas to form new interstellar life: Baby stars that mature, age and may eventually complete the circle of life by becoming supernovae themselves.