An artist’s impression of a possible ninth planet. It would be quite large — at least as big as Earth — with a thick atmosphere around a...

An artist’s impression of a possible ninth planet. It would be quite large — at least as big as Earth — with a thick atmosphere around a...

An artist’s impression of a possible ninth planet. It would be quite large — at least as big as Earth — with a thick atmosphere around a...

An artist’s impression of a possible ninth planet. It would be quite large — at least as big as Earth — with a thick atmosphere around a...

An artist’s impression of a possible ninth planet. It would be quite large — at least as big as Earth — with a thick atmosphere around a...

July 15th was a historic occasion as it marked the first time we were able to see close-up pictures of Pluto’s surface.  Traveling at...

July 15th was a historic occasion as it marked the first time we were able to see close-up pictures of Pluto’s surface.  Traveling at...

July 15th was a historic occasion as it marked the first time we were able to see close-up pictures of Pluto’s surface.  Traveling at...

July 15th was a historic occasion as it marked the first time we were able to see close-up pictures of Pluto’s surface.  Traveling at...

July 15th was a historic occasion as it marked the first time we were able to see close-up pictures of Pluto’s surface.  Traveling at...

Since Pluto’s discovery by Clyde Tombough in 1930, it has remained a great mystery.  It’s difficult to study since it’s about 3 billion...

Since Pluto’s discovery by Clyde Tombough in 1930, it has remained a great mystery.  It’s difficult to study since it’s about 3 billion...

Since Pluto’s discovery by Clyde Tombough in 1930, it has remained a great mystery.  It’s difficult to study since it’s about 3 billion...

Since Pluto’s discovery by Clyde Tombough in 1930, it has remained a great mystery.  It’s difficult to study since it’s about 3 billion...

Since Pluto’s discovery by Clyde Tombough in 1930, it has remained a great mystery.  It’s difficult to study since it’s about 3 billion...

The first color image of Pluto and its moon, Charon, was taken by the Ralph color imager aboard NASA’s New Horizons spacecraft on April...

The first color image of Pluto and its moon, Charon, was taken by the Ralph color imager aboard NASA’s New Horizons spacecraft on April...

The first color image of Pluto and its moon, Charon, was taken by the Ralph color imager aboard NASA’s New Horizons spacecraft on April...

The first color image of Pluto and its moon, Charon, was taken by the Ralph color imager aboard NASA’s New Horizons spacecraft on April...

The first color image of Pluto and its moon, Charon, was taken by the Ralph color imager aboard NASA’s New Horizons spacecraft on April...