Astronomers have discovered more than 5,000 planets in other star systems, most of them found by the Kepler space telescope. This graphic provides an overview of the types of worlds discovered so far.
That sound represents the first confirmed exoplanets — planets that orbit stars other than the Sun. At the end of 1992, only two such planets were known — orbiting the dead heart of an exploded star.
The first planets orbiting a star similar to the Sun were announced in 1995. By last spring, the number had passed 5,000, with thousands more possible planets awaiting confirmation. NASA put together an audio track as a timeline of all the discoveries. Each note represents a confirmed planet, with the pitch representing the planet’s distance from its star.
For about two minutes on the afternoon of August 21, the sky over Nashville will turn almost as dark as night. Ditto Casper, Wyoming; Columbia, South Carolina, and the southern suburbs of St. Louis. They will be darkened by one of nature’s most spectacular events: a total solar eclipse. It may be the most-watched eclipse in history.