Supernovas Near Earth 10 Million Years Ago

Once every 50 years, more or less, a massive star explodes somewhere in the Milky Way.  The resulting blast is terrifyingly powerful, pumping out more energy in a split second than the sun emits in a million years.  At its peak, a supernova can outshine the entire Milky Way.

It seems obvious that you wouldn't want a supernova exploding near Earth.  Yet there is growing evidence that one did—actually, more than one. About 10 million years ago, a nearby cluster of supernovas went off like popcorn.  We know because the explosions blew an enormous bubble in the interstellar medium, and we're inside it.

A new ScienceCast video examines evidence that our solar system is inside a bubble of hot gas created by supernova explosions.  Play it

Astronomers call it "the Local Bubble." It is peanut-shaped, about 300 light years long, and filled with almost nothing. Gas inside the bubble is very thin (0.001 atoms per cubic centimeter) and very hot (roughly a million degrees)—a sharp departure from ordinary interstellar material.

More - Link >>> http://science.nasa.gov/science-news/science-at-nasa/2014/26aug_localbubble/

Source: NASA Science News.

2014: 75th Year of Pittsburgh's Buhl Planetarium

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