A huge heart-shaped feature on the surface of Pluto has intrigued astronomers since NASA’s New Horizons spacecraft captured it in a 2015 image. Now, researchers think they have solved the mystery of how the distinctive heart came to be — and it could reveal new clues about the dwarf planet’s origins.
The feature is called Tombaugh Regio in honor of astronomer Clybe Tombaugh, who discovered Pluto in 1930. But the heart is not all one element, scientists say. And for decades, details on Tombaugh Regio’s elevation, geological composition and distinct shape, as well as its highly reflective surface that is a brighter white than the rest of Pluto, have defied explanation.
A deep basin called Sputnik Planitia, which makes up the “left lobe” of the heart, is home to much of Pluto’s nitrogen ice.
The basin covers an area spanning 745 miles by 1,242 miles (1,200 kilometers by 2,000 kilometers), equivalent to about one-quarter of the United States, but it’s also 1.9 to 2.5 miles (3 to 4 kilometers) lower in elevation than the majority of the planet’s surface. Meanwhile, the right side of the heart also has a layer of nitrogen ice, but it’s much thinner.
Through new research on Sputnik Planitia, an international team of scientists has determined that a cataclysmic event created the heart.
After an analysis involving numerical simulations, the researchers concluded a planetary body about 435 miles (700 kilometers) in diameter, or roughly twice the size of Switzerland from east to west, likely collided with Pluto early in the dwarf planet’s history.
