Nearing the end of a nine-and-a-half-year journey to the solar system's unexplored outer reaches, scientists said they were excited about the new images of Pluto being received by the New horizons spacecraft on 12 July.

Two days away from the historic flyby of Pluto, Nasa's New Horizons spacecraft is sending back pictures of the small planet that are showing images of it with more clarity and definition according to principle investigator Alan Stern.

"Now when you look at an image of Pluto, you see a real planet there you see a complex world that just begs for exploration and yet we're going to do a hundred times better than that with the images made on Tuesday in fact the images made will have 10,000 times as many pixels in each pixel as we see now," Stern said.

Nasa's New Horizon's spacecraft is on track to fly within about 7,750 miles of Pluto on 14 July, despite a computer glitch that threatened the important flyby of the unexplored planet.

Scientists believe Pluto and the thousands of other recently discovered Kuiper Belt objects are frozen mini-planets and building blocks left over from the solar system's formation 4.6 billion years ago.

Scientists suspect Pluto, Charon and their four small moons, all discovered in Hubble images after New Horizons launched, formed after an ancient collision of two icy bodies.

That theory will be tested with the new evidence of the tumbling, wobbly moons, and observations by New Horizons.

Launched in January 2006, New Horizons will be the first spacecraft to visit Pluto. It will then head into the Kuiper Belt for a possible flyby of a second object in 2019.