On February 18th, 1930, a 24-year-old Kansas farmhand-turned-astronomer made a discovery that forever changed our understanding of the Solar System. On that evening, Clyde Tombaugh, who had grown up on family farms in Illinois and Kansas, discovered Pluto. Tombaugh’s discovery nearly doubled the size of the known solar system overnight. Whether you prefer to call it a planet or a dwarf planet, for more than eight decades Pluto has remained one of the most poorly understood objects in the solar system, due to its small size and great distance from Earth.
All that is about to change though; in mid-July, NASA’s New Horizons spacecraft will arrive at Pluto after a nearly decade-long journey to the outer reaches of the solar system. This will be the first time that Pluto and its five small moons have been visited by a space probe. What exactly New Horizons will find remains a mystery. Even the best pictures of Pluto taken from Earth show little more than a fuzzy gray ball. Detailed analysis of sunlight reflected by Pluto tells us that it is covered in frozen nitrogen, methane, and carbon dioxide. Beyond this, little is known about the most famous iceball in the solar system.
New Horizons will fly past Pluto on July 14th. For two weeks before and after, the spacecraft will be busy taking high resolution photos of Pluto and measuring the composition of its surface and thin atmosphere. Astronomers hope that the information gathered will shed light on how Pluto and its thousands of icy outer solar system companions formed. Even today, nearly 20 years after his death, Clyde Tombaugh’s spirit of discovery lives on in the New Horizons mission. Attached to the spacecraft is a small container of Tombaugh’s ashes, carrying a piece of his legacy to the planet (or dwarf planet) he discovered so many years earlier.
Western Slope Skies is produced by members of the Black Canyon Astronomical Society. Today’s feature was written by Zach Schierl and recorded by Art Trevena.