How Long is a Day on Pluto?

Pluto takes 6.4 Earth days (6 days 9 hours and 36 minutes) to complete one rotation, so this is how long a day is on Pluto.

When the New Horizons spacecraft flew by Pluto and its moons in July of 2015, it took hundreds of images. The montage above shows Pluto rotating over the course of a full day. It provides our first close-up look at what a day on Pluto might be like.

What Makes a Day?

To clarify, one day on any planet is the time it takes for the planet to completely spin around and make one full rotation about its axis. Here on Earth that takes 24 hours, but each planet has a different rotational speed. Since Pluto rotates more slowly than Earth, its day is longer.

This artist’s concept of the frosty surface of Pluto with Charon and our sun as backdrops illustrates that while sunlight is much weaker than it is here on Earth, it isn’t as dark as you might expect. In fact, you could read a book on the surface of Pluto. Credit: NASA.

What is a Day on Pluto Like?

Since Pluto is so much farther from the Sun, the amount of sunlight that reaches Pluto is much less that what we receive on Earth. It has been estimated that the Sun would appear about 1,000 times dimmer than it appears on Earth. NASA has said that instead of a big yellow disc, the Sun would look more like other stars, although the Sun would be the brightest object in the sky.

However, it isn’t completely dark on Pluto. Since Pluto has a thin atmosphere, that atmosphere would scatter the light, but probably not enough to make a bright sky like we see on Earth or Mars. NASA says that at a certain time near dawn and dusk each day, the illumination on Earth matches that of high noon on Pluto. NASA has a “Pluto Time” website where you can plug in your location and find out what time of day you could experience the same amount of light (on a clear day) that Pluto is receiving.

A graphic depicting the Pluto system’s orbital orientation. Credit: NASA.

However, seasonal variations of daylight on Pluto can be extreme. Pluto’s year is 248 Earth years long, and so the seasons are very long. Plus, compared to most of the planets and their moons, the whole Pluto-Charon system is tipped on its side. Therefore, Pluto rotates on its “side” in its orbital plane, with an axial tilt of 122 degrees – very similar to the “sideways” planet Uranus. So at its solstices, one-fourth of Pluto’s surface is in continuous daylight, while another fourth is in continuous darkness.

Take a look at the Solar System from above, and you can see that the planets make nice circular orbits around the Sun. But dwarf planet’s Pluto’s orbit is very different. It’s highly elliptical, traveling around the Sun in a squashed circle. And Pluto’s orbit is highly inclined, traveling at an angle of 17-degrees. This strange orbit gives Pluto some unusual characteristics, sometimes bringing it within the orbit of Neptune. Credit: NASA

Also, Pluto travels around the Sun in a very elliptical orbit. At its closest point, or perihelion, Pluto gets as close as 4.4 billion km from the Sun. At its most distant point, or aphelion, Pluto is 7.4 billion km from the Sun. Therefore, the amount of sunlight varies throughout Pluto’s long year depending on how close or far it is to the Sun.

A portrait from the final approach of the New Horizons spacecraft to the Pluto system on July 11, 2015. Pluto and Charon display striking color and brightness contrast in this composite image. Credit: NASA-JHUAPL-SWRI.

One interesting note is that Pluto and Charon are a binary planet system, and the two worlds are in orbit around each other. Also, Pluto’s moon Charon is tidally locked around Pluto. This means that Charon takes 6 days and 9 hours to orbit around Pluto – the same amount of time it takes for a day on Pluto. This means that Charon is always at the same place in the sky when seen from Pluto.

You would have the same view from Charon as well. From some vantage points on Charon, Pluto would always hang at the same spot in the sky, and for other parts, you wouldn’t be able to see Pluto at all.

New Horizons also captured a full day rotation for Charon, too, which you can see below:

On approach to the Pluto system in July 2015, the cameras on NASA’s New Horizons spacecraft captured images of the largest of Pluto’s five moons, Charon, rotating over the course of a full day. The best currently available images of each side of Charon taken during approach have been combined to create this view of a full rotation of the moon. Credit: NASA/JHUAPL/SwRI.

The images used in the Pluto and Charon “day” montages were taken by the Long Range Reconnaissance Imager (LORRI) and the Ralph/Multispectral Visible Imaging Camera as the New Horizons spacecraft zoomed toward the Pluto system, and in the various images the distance between New Horizons and Pluto decreased from 5 million miles (8 million kilometers) on July 7 to 400,000 miles (about 645,000 kilometers) on July 13, 2015. You can read more about these images here on Universe Today, and here on the New Horizons website.

Nancy Atkinson

Nancy has been with Universe Today since 2004, and has published over 6,000 articles on space exploration, astronomy, science and technology. She is the author of two books: "Eight Years to the Moon: the History of the Apollo Missions," (2019) which shares the stories of 60 engineers and scientists who worked behind the scenes to make landing on the Moon possible; and "Incredible Stories from Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos" (2016) tells the stories of those who work on NASA's robotic missions to explore the Solar System and beyond. Follow Nancy on Twitter at and and Instagram at and

Recent Posts

27 to 78 cm of sea Level Rise Could be Locked in From Melting Greenland ice Caps

Recent climate research, published in the Nature Climate Change journal has confirmed that melting icecaps…

15 hours ago

Underground Liquid Water Detected on Mars? Maybe not

New research from Cornell University shows that radar reading from Mars' South Pole region may…

20 hours ago

LICIACube Sends Home Images of the DART Impact and the Damage to Dimorphos

The Light Italian CubeSat for Imaging of Asteroids (LICIACube) has returned a series of close-up…

23 hours ago

After Getting Slammed by DART, Asteroid Dimorphos has Grown a Tail

More images and details keep coming in about the asteroid intentionally smashed by NASA’s Double…

24 hours ago

Gaze Down Into the eye of Hurricane Ian, Seen From Orbit

NASA and NOAA satellites -- as well as astronauts on the ISS -- captured some…

1 day ago

Scientists Have Been Underestimating the Asteroid That Created the Biggest Known Crater on Earth

Ancient impacts played a powerful role in Earth's complex history. On other Solar System bodies…

2 days ago