Despite searing daytime temperatures, Mercury, the planet closest to the sun, has ice and frozen organic materials inside permanently shadowed craters in its North Pole.

NASA scientists said on Thursday that Earth-based telescopes have been compiling evidence for ice on Mercury for 20 years, but the finding of organics was a surprise.

"This indeed consistent with the proposal that the radar deposits are some kind of ice, cold trapped in permanently shadowed regions," said MESSENGER Principal Investigator, Sean Soloman.

The discoveries of ice and organics, painstakingly pieced together for more than a year, are based on computer models, laboratory experiments and deduction, not direct analysis.

"All the results are pointing to the same place and that definitely an exclamation point," said MESSENGER participating scientist, David Lawrence.

Scientists don't believe Mercury is or was suitable for ancient life, but the discovery of organics on an inner planet of the solar system may shed light on how life got started on Earth.