When I was your age, Pluto was a planet.

In 2006, the International Astronomical Union decided to create a new category for solar system objects called "dwarf planets", and Pluto was reclassified as a dwarf planet.

The Solar System has only eight planets now as Pluto, which was the ninth, has been reclassified as a dwarf planet.

Little is known about Pluto.

Centuries later, there were "lighthouse" outposts as far as Pluto and its moon Charon.

Pluto is not alone. It has a friend named Charon.

Charon is considered to be a satellite of the (dwarf) planet Pluto. However, because its diameter is more than half as large as that of Pluto itself, it can be considered an equal partner; and Pluto and Charon can be considered a double planet.

Charon is considered to be a satellite of the (dwarf) planet Pluto. However, because its diameter is more than half as large as that of Pluto itself, it can be considered an equal partner; and Pluto and Charon can be considered a double planet.

Charon is considered to be a satellite of the (dwarf) planet Pluto. However, because its diameter is more than half as large as that of Pluto itself, it can be considered an equal partner; and Pluto and Charon can be considered a double planet.

Russia is larger than Pluto.

A long time ago when Pluto was still a planet, there was a boy named Tom.

The mission will be considered a success if the probe reaches Pluto.

The demotion of Pluto from the status of a planet was a very hotly debated issue within the astronomical community.

In 2006, astronomers re-classified Pluto as a dwarf planet.

Pluto has a very unusual orbit. Once every 248 Earth years, Pluto swings inside the orbit of Neptune. It stays there for twenty years. During those twenty years, Pluto is closer to the Sun than Neptune.

Pluto has a very unusual orbit. Once every 248 Earth years, Pluto swings inside the orbit of Neptune. It stays there for twenty years. During those twenty years, Pluto is closer to the Sun than Neptune.

Pluto has a very unusual orbit. Once every 248 Earth years, Pluto swings inside the orbit of Neptune. It stays there for twenty years. During those twenty years, Pluto is closer to the Sun than Neptune.

Pluto has more in common with Triton, Neptune's largest moon, than it does with any of the eight planets in our solar system. Pluto is actually smaller than Triton.

Pluto has more in common with Triton, Neptune's largest moon, than it does with any of the eight planets in our solar system. Pluto is actually smaller than Triton.

Pluto is tilted 122.5 degrees on its axis, which basically means that it is rotating on its head!

Pluto, which was once called a planet, is now called a dwarf planet.

Eris is the largest known dwarf planet in our solar system. It is a little larger than Pluto.

Eris is the most distant member of our solar system known at this time. It is 3 times farther out than Pluto.

After Pluto and Eris, Makemake is the third largest dwarf planet.

The New Horizons spacecraft was launched in 2006, and will arrive at Pluto in 2015. It will be the first spacecraft to visit that very distant dwarf planet.

Clyde Tombaugh was only twenty-four years old when he discovered Pluto.

After ten months of very hard work, sometimes working through the night in an unheated dome, Clyde Tombaugh discovered an object he named Pluto.

For many years, Pluto was considered to be the ninth planet in our solar system.

Russia is bigger than Pluto.

I cannot sleep. I am just electrified by the knowledge of our imminent approach toward Pluto.

New Horizons has taken pictures of Pluto.

Pluto is a dwarf planet.

This is a statue of Pluto.

Pluto is closer to the sun than Neptune for about 8% of its orbit.

Pluto is a dwarf planet that lies in the Kuiper Belt.

Pluto is only about half the width of the United States.

Pluto and Charon are tipped on their sides.

Personally, I think there is some truth to both sides. I believe the moon landing and Pluto fly-by were real, but all of the Mars landings and flybys of Jupiter's moons were hoaxes.

There's no life on Pluto.

We know what Pluto looks like now.

How big is Pluto?

NASA's New Horizons mission, for example, was the first spacecraft to visit Pluto in the outer solar system. The spacecraft’s images of Pluto show a surprisingly complex world with giant ice mountains that had never been seen before.

NASA's New Horizons mission, for example, was the first spacecraft to visit Pluto in the outer solar system. The spacecraft’s images of Pluto show a surprisingly complex world with giant ice mountains that had never been seen before.

Halley has a highly elongated orbit that takes it very close to the Sun and then flings it out into the outer solar system, well past the orbit of Pluto.

Pluto can reach temperatures of minus 223 degrees Celsius.

Pluto, located on the outskirts of our solar system, has a different kind of mountain range, made up of ice. The ice mountains are about 11,000 feet tall. The New Horizons spacecraft spotted them for the first time when it flew by the dwarf planet in July 2015.

Pluto was the smallest planet until August 2006, when the International Astronomical Union reclassified it as a dwarf planet. It is the largest dwarf planet known.

Pluto is composed of a large rocky core wrapped in thick layers of ices.

The key reason why Pluto is no longer considered a planet is that it is one among thousands to millions of other objects orbiting within the Kuiper Belt region. Also, the icy dwarf planet is not massive enough to clear debris from its orbit.

NASA’s New Horizons mission revolutionized our knowledge of Pluto when it flew past that distant world in July 2015.

Pluto is the 9th largest body orbiting the Sun.

Pluto was regarded as the 9th planet for more than 75 years.

Pluto is not really a planet.

Pluto was reclassified as a dwarf planet.

Pluto is small.

Pluto is made of rocky ice.

Pluto is about two thirds rock and one third ice.

Pluto has a lot of ice.

Pluto is the largest dwarf planet in the solar system.

Pluto has a thin atmosphere.

Pluto has an atmosphere.

Pluto is very far from the sun.

Pluto is sometimes closer to the sun than Neptune is.

Pluto is so far from the sun.

Pluto is a cold world.

Pluto is very dark.

Pluto rotates on its side.

Like Uranus, Pluto rotates in its side.

Pluto has moons.

Pluto was discovered in the 20th century.

Pluto was discovered by Clyde Tombaugh in 1930.

Pluto was found by Clyde Tombaugh in 1930.

Pluto is so small and distant.

The New Horizons space probe flew by Pluto.

The New Horizons space probe flew by the Pluto system.

Pluto is very far from us.

Pluto is a very far celestial object.

The New Horizons spacecraft sent a lot of images of Pluto.

What does Pluto look like?

The New Horizons space probe sent a lot of photos of Pluto.

What did New Horizons discover during its fly-by of Pluto?

The geology of Pluto is very interesting.

Pluto has ice plains.

Pluto is very cold.

Pluto is extremely cold.

Pluto has glaciers and mountain ranges.

Pluto has interesting geological features.

On Pluto, ice turns directly into ice and this is called sublimation.

Pluto has vast ice plains.

Pluto is tightly locked to its largest moon, Charon.

Pluto has spectacular geological features.

Pluto has cryovolcanoes.

Pluto has ice volcanoes.

Pluto has hydrocarbons.

Pluto is a bizarre world.

Pluto is a unique world.

Pluto is a wonderful world.

Pluto is a solar system object.

Pluto has lots of ice.

Pluto is so small.

Pluto has impressive landscapes.