Is Pluto a planet? Why it isn't, and where Pluto is now

No. Since 24 August 2006, Pluto has officially been a dwarf planet, and our solar system has eight planets. That day the International Astronomical Union (IAU), the group that names and classifies objects in space, decided what counts as a planet. Pluto failed one of its three rules. It is still a real, fascinating world, just in a different category. The quick facts:

One astronomical unit (au) is the average distance between Earth and the Sun, about 150 million km; see how far the Sun is from Earth.

Is Pluto a planet?

Not any more. At its meeting in Prague in 2006, the IAU agreed that a planet is a body that:

1. orbits the Sun, 2. is massive enough for its own gravity to pull it into a nearly round shape, and 3. has cleared the neighbourhood around its orbit.

A body that meets the first two rules but not the third, and is not a moon, is a dwarf planet. Pluto passes rules 1 and 2 but fails rule 3. The IAU's resolution named Pluto a dwarf planet and the prototype of a new group of objects beyond Neptune, and it listed the eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

Why is Pluto not a planet anymore?

Because Pluto does not dominate its part of space. It lies in the Kuiper Belt, which NASA describes as a doughnut-shaped region of icy objects beyond the orbit of Neptune, home to Pluto, most of the known dwarf planets and some comets. NASA explains the third rule this way: a planet must "be big enough that its gravity cleared away any other objects of similar size near its orbit around the Sun". NASA's JPL puts it the other way round: a dwarf planet "is not massive enough to gravitationally dominate its region". So clearing the neighbourhood does not mean removing every last comet or rock; it means having enough mass for its gravity to dominate its orbital neighbourhood, and Pluto does not. NASA's Pluto page sums up the reason as "because other objects might cross its orbit".

The discovery of Eris, a world beyond Neptune that NASA says is nearly the same size as Pluto, helped prompt the decision.

Pluto's orbit even crosses Neptune's, as seen from above. Using daily NASA JPL Horizons positions, we found that Pluto was closer to the Sun than Neptune from about February 7, 1979 to about February 11, 1999. Yet the two never get close. NASA explains that Pluto is in resonance with Neptune: "For every three orbits completed by Neptune, Pluto makes two orbits," so Pluto "never comes close enough to Neptune to be affected much by its gravity". In our 1850-2199 samples, taken every 10 days, the smallest gap between them was about 18.9 au, and when Pluto was nearest the Sun in 1989, Neptune was 28.9 au away (our calculation).

How many planets are in our solar system?

Eight: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Before 2006, most people learned nine, with Pluto as the ninth.

NASA says the IAU recognizes five dwarf planets: Ceres, Pluto, Haumea, Makemake and Eris. Ceres is the only one in the inner solar system, in the asteroid belt between Mars and Jupiter; the others are far beyond Neptune.

Pluto is small. NASA gives its width as about 2,377 km: about two-thirds of the Moon's width and only about half the width of the United States. It is the largest dwarf planet, just slightly larger than Eris, which NASA puts at about 2,326 km across.

Where is Pluto now, and how far away is it?

On November 1, 2026, Pluto was about 35.71 au from Earth: 5.34 billion km, or 3.32 billion miles. Its light takes about 4.95 hours to reach us (our calculation with NASA JPL Horizons). In our sky it sits in the constellation Capricornus. Its closest approach to Earth in 2027 will be around July 26, at about 34.81 au. Pluto's distance from Earth keeps changing as both worlds move around the Sun.

Its distance from the Sun changes a lot too, because its orbit is an oval; the range of about 30 to 49 au below is its distance from the Sun, not from Earth. With JPL Horizons data we found that it was closest to the Sun around September 7, 1989, at 29.66 au, and will be farthest around 2114, at about 49.32 au. On November 1, 2026 it is about 35.63 au from the Sun and slowly moving away.

Can you see Pluto? Not with your eyes or binoculars. JPL Horizons gives it a brightness of about magnitude 14.5 to 14.6 between November 2026 and December 2027. In astronomy, a bigger magnitude means a fainter object, and under dark skies the faintest stars you can see are around magnitude 6, so Pluto is thousands of times too faint for your eyes. You need a telescope, a dark sky and a detailed star chart, and even then it looks like a faint star: NASA notes that Pluto appears so small that 18,000 Plutos would fit across the full Moon.

What is Pluto like?

Cold, icy and surprisingly varied. NASA's Pluto facts give an average temperature of about -232 °C (-387 °F). Its largest plains appear to be made of frozen nitrogen and show no craters, while its mountains are big blocks of water ice, up to 2 to 3 km high. So yes, there is water on Pluto, frozen solid.

Pluto has a thin atmosphere, mainly nitrogen with some methane and carbon monoxide. NASA says most of that atmosphere may freeze and fall as snow to the surface. New Horizons photographed the atmosphere as a blue haze glowing around Pluto's night side.

A day on Pluto lasts about 153 hours and a year about 248 Earth years. Pluto has five known moons and no known rings, according to NASA. Could anything live there? Nobody has found any sign of life; see is there life on other planets?

How long does it take to get to Pluto?

NASA's New Horizons spacecraft took about 9.5 years. It launched on 19 January 2006 at about 58,500 km/h (36,400 mph), NASA says, passed Jupiter in February 2007 and flew past Pluto on 14 July 2015. In NASA's JPL trajectory data, its closest point was about 13.7 thousand km from Pluto's centre, or roughly 12,500 km above the surface (our calculation). Its radio signals took four hours and 25 minutes to reach Earth.

New Horizons took all the photos of Pluto in this article. NASA says it is now deep in the Kuiper Belt, speeding away from the Sun, much like Voyager 1 far beyond it.

Pluto FAQ

When did Pluto lose its planet status? On 24 August 2006, when the IAU voted on the definition of a planet in Prague.

Will Pluto ever be a planet again? Only if the IAU changes its definition. NASA still lists Pluto as one of the five dwarf planets recognized by the IAU.

What is the Kuiper Belt? A doughnut-shaped region of icy objects beyond Neptune, home to Pluto, most of the known dwarf planets and some comets, according to NASA.

What will happen on March 23, 2178? That date is often shared as the day Pluto finishes its first full orbit since it was discovered in 1930. Our calculation with NASA JPL Horizons puts Pluto at the same angle around the Sun, seen from above, as on its discovery day around February 21, 2178. That does not mean it returns to exactly the same point in space, and the exact day depends on how you measure a full orbit.

Does Pluto have rings? No known rings, NASA says.

Can it snow on Pluto? NASA says most of its thin atmosphere may freeze and fall as snow to the surface.

How long is a day on Pluto? About 153 hours, or about 6.4 Earth days (our conversion of NASA's figure).

How cold is Pluto? About -232 °C (-387 °F) on average, and as cold as -240 °C, according to NASA.

How many moons does Pluto have? Five: Charon, Nix, Hydra, Kerberos and Styx. Charon, the largest, is shown in the picture above. For comparison, see how many moons Jupiter has.

Is Pluto smaller than the Moon? Yes. Pluto is about two-thirds of the Moon's width.

Who discovered Pluto, and who named it? Clyde Tombaugh discovered it on February 18, 1930 at Lowell Observatory in Arizona, NASA says. The name was suggested by Venetia Burney in Oxford, England, and chosen by Lowell Observatory, according to NASA.

How we checked

The definition comes from the IAU's own record of its 2006 resolutions. Positions of Pluto, Neptune and New Horizons come from NASA JPL Horizons, fetched on 1 November 2026. From the position tables we calculated Pluto's distance from the Sun, its closest and farthest points (refined between samples), the dates it was closer to the Sun than Neptune (from daily positions), the smallest Pluto-Neptune gap in samples every 10 days from 1850 to 2199, and when Pluto is back at the same angle around the Sun as on its discovery day. Pluto's distance from Earth, its brightness and the one-way light time came from Horizons' observer tables; we converted the distance and time units. Facts and photos come from NASA, listed under Sources. We checked all sources on 1 November 2026.

None of the images or videos is AI-generated.