Pluto Day
Join us in honoring Pluto's discovery and its place in our solar system.
- Roots
- Discovered by Clyde Tombaugh
- Vibe
- Curiosity and wonder about the cosmos
- Also on Feb 18
- Battery Day · Crab Stuffed Flounder Day · Drink Wine Day
- Hashtag
- #PlutoDay
3 ways to celebrate
Stargaze tonight
Head outside with a blanket and look for planets in the night sky.
Watch a space film
Gather friends for a movie night about space exploration.
Build a model
Make a solar system model and debate Pluto's planet status.
Plan ahead
Pluto Day is observed on February 18 every year. Here is where it lands for the next ten years, handy for planners, marketers and party people.
Fast facts
The story
Pluto Day, observed on February 18, commemorates the day in 1930 when astronomer Clyde Tombaugh discovered the dwarf planet Pluto at the Lowell Observatory in Flagstaff, Arizona. This celestial body, once considered the ninth planet of our solar system, became a topic of intrigue and debate among astronomers and the public alike. As we celebrate this day, we reflect on the significance of Pluto's discovery and its impact on our understanding of the cosmos.
Read the full story
The discovery of Pluto was the result of meticulous research and observation. Tombaugh, who was only 24 at the time, used a technique called 'comparative astrophotography' to identify Pluto against the backdrop of stars. His dedication and careful attention to detail not only led to the identification of Pluto but also opened the door to further exploration of the outer solar system. The discovery sparked excitement and curiosity that continues to this day.
In 2006, Pluto's status was redefined by the International Astronomical Union, classifying it as a 'dwarf planet.' This decision was met with mixed reactions, igniting a debate over what constitutes a planet. Despite this change, Pluto remains a beloved object of study and fascination, inspiring countless enthusiasts and researchers alike. Its complex geology and atmosphere provide valuable insights into planetary science.
On Pluto Day, enthusiasts around the world engage in various activities to celebrate this unique celestial body. From stargazing events to educational programs, the day serves as a reminder of our ongoing quest to understand the universe. As we look forward to more discoveries, Pluto will always hold a special place in our hearts as a symbol of exploration and wonder.
Did you know?
Pluto's Discovery Year
Pluto was discovered in 1930.
Number of Moons
Pluto has five known moons.
Pluto's Distance from Sun
Pluto orbits at an average distance of about 3.7 billion miles from the Sun.
Pluto's Atmosphere
Pluto has a thin atmosphere mainly composed of nitrogen.
Temperature on Pluto
Surface temperatures can drop to -375 degrees Fahrenheit.
Pluto's Heart Shape
A large heart-shaped glacier is one of Pluto's most famous features.
Tombaugh's Legacy
Clyde Tombaugh discovered Pluto in 1930.
Around the world
Every culture celebrates a little differently.
- USNorth AmericaPluto was discovered in Arizona, making the U.S. a focal point for astronomy.
- GBEuropeEuropean observatories contribute significantly to space research.
- AUAustraliaAustralia hosts stargazing events for Pluto Day.
- JPAsiaJapan's space agencies actively study celestial bodies.
- BRSouth AmericaAstronomy is growing in popularity across the continent.
- CACanadaCanadian scientists are involved in planetary exploration.
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