Scientists have discovered a planet more like Earth than any other found before, they said on Wednesday. It's 20,000 light-years away, just shy of the center of the Milky Way.

The discovery, which the scientists called "groundbreaking," was made using a technique noted in 1912 by Albert Einstein through a network of telescopes positioned around the globe. The planet takes the nondescript name "OGLE-2005-BLG-390" after one such telescope, named OGLE, for Optical Gravitational Lensing Experiment.

OGLE, based in Poland's Warsaw University Observatory, was first used to spot the object on July 11, 2005.

The planet is five times the mass of Earth, but it's still considered the smallest and coolest ever detected outside of the solar system, according to the scientists. It circles a red parent star, which is five times smaller than the Sun, in about 10 years. Because the parent star is cool and within a large orbit, scientists believe OGLE's surface is icy and too cold for liquid water at an estimated 220 degrees Centigrade below zero.