Tombaugh Regio — the large, pale heart that dominates Pluto's terrain — is made of nitrogen ice that accumulated after a huge, slow-motion impact, new research suggests.

The large heart-shaped region may have formed after a massive but slow-moving object collided with Pluto at a strange angle.

Scientists have worked out the mystery of why Pluto has a heart. Researchers believe the huge heart-shaped feature on the planet's surface was likely caused by a "giant and slow oblique-angle impact".

The mystery of how Pluto got a giant heart-shaped feature on its surface has finally been solved by an international team of astrophysicists led by the University of Bern and members of the National Center of Competence in Research (NCCR) PlanetS.

The mystery of how Pluto got a giant heart-shaped feature on its surface has finally been solved by an international team of astrophysicists led by the University of Bern and members of the National Center of Competence in Research (NCCR) PlanetS.

In Pluto's early years, an object around 400 miles wide crashed into it at an unusual angle, resulting in this surface feature.

The heart, also known as the Tombaugh Regio, was discovered in 2015.

The "heart" of Pluto, officially named Tombaugh Regio, has fascinated both the public and scientists since its discovery