earth

Via Huffington Post:

The irregularly shaped hole spans about 400,000 kilometers (250,000 miles) at its widest point, said Dr. C. Alex Young, associate director for science for the heliophysics division at the space agency's Goddard facility in Greenbelt, Maryland. Its total surface area is about 410 times that of the Earth, he said (see below for size comparison).

NASA's Kepler Space Telescope recently discovered an Earth-like planet orbiting a nearby star within the habitable zone of our galaxy. Kepler-186f is approximately 500 light-years from Earth in the Cygnus constellation.

Not pictured: The fact that going through a wormhole will literally kill you.