Cold, “Dead” World Alive and Kicking
July 28, 2015
New Horizons discovered flowing ices in Pluto’s heart-shaped feature. Swirl-shaped patterns of light and dark suggest that a surface layer of ices has flowed around obstacles and into depressions, similar to how glaciers behave on Earth.
Credit: NASA/JHUAPL/SwRI
Since its discovery in 1930, many astronomers have thought the dwarf planet Pluto to be a cold, dead world. As data pour in from the United States National Aeronautics and Space Administration (NASA) probe New Horizons, however, Pluto is proving itself to be far from dead—although it is still cold!
New Horizons was the first probe sent to Pluto. It explored the dwarf planet and its large moon, Charon. Mission managers also hope to study other objects in the Kuiper belt, the band of icy bodies beyond the orbit of Neptune. The measurements made by New Horizons will help scientists learn about the nature of these Kuiper belt objects (KBO’s), thought to be the remains of the material that came together to form the planets.
New Horizons flew past Pluto on July 14, 2015. During its time near the dwarf planet, the probe captured dozens of photographs along with other scientific data. Because New Horizons is so far away, however, it will take 16 months for the probe to return all of its information to Earth. But New Horizons has already sent home amazing photographs and is challenging earlier ideas about Pluto.
At Pluto’s estimated surface temperature of –385 °F (–232 °C), any water would be frozen solid, and the ice would be extremely rigid and brittle. But at those temperatures, ices made up of other molecules can still flow over many years. New Horizons has revealed glaciers made of carbon monoxide, methane, and nitrogen in the large, heart-shaped region on Pluto’s surface. These glaciers appear to have flowed down from higher points to lower ones, just as water-ice glaciers do here on Earth.
An image taken on July 13, 2015, from New Horizons, when the probe was 476,000 miles (768,000 kilometers) from the surface. The heart-shaped region on Pluto holds glaciers made of carbon monoxide, methane, and nitrogen.
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Furthermore, astronomers have estimated that this glacial activity has occurred relatively recently. Before New Horizons, most scientists had assumed that Pluto had changed very little in the past 4 billion years. But the glaciers formed within the last 30 million years and may still be flowing today. In geological terms, that is not very long at all—more than 35 million years after the dinosaurs went extinct on Earth, for example. Even some 3.5 billion miles (6 billion kilometers) away from the sun, Pluto has shown itself to be an active—if icy—world!
Other World Book Behind the headlines:
- Are We There Yet? (April 15, 2015)
- A Heart and A Whale With a Doughnut In Its Tail? (July 9, 2015)
- Pluto Dazzles In First Close-Up (July 17, 2015)
