Pluto’s Heart Explained: What Caused the Dwarf Planet’s Love Symbol?

pluto's heart explained astronimate

Since NASA’s groundbreaking New Horizons fly-by of Pluto in July 2015, we’ve unlocked extensive information about the former ninth world. However, nothing caught the world’s attention more than a giant “heart” shape on Pluto’s surface. But, what is Pluto’s heart made of? Astronimate investigates in Pluto’s Heart Explained.

Pluto’s Heart Explained: Composition

Pluto's heart explained surface features

Pluto’s surface shows well-defined regions based on conditions and composition. For instance, a brown belt wraps the planet’s equator. Actually, the belt is Pluto’s raw surface, bare terrain. Alternatively, the majority of the surface shows lighter colors, covered in methane (CH4) frost.

Finally, we see a charming heart hugging the planet’s brown belt. In fact, massive quantities of nitrogen ice and other frozen materials have formed this sign of affection (explained below).

Pluto’s Heart Explained: Formation

Named after Pluto discoverer, Clyde Tombaugh, Pluto’s heart is formally deemed Tombaugh Regio. And, until recently, how the 1,200-mile-wide heart formed has been a mystery. However, the New Horizon’s mission has helped us unlock that mystery.

Deep basins cover Pluto’s surface, hidden from the Sun’s light. Plus, Pluto’s already chilling temps allow frozen materials to easily build up. Over time, basins fill up with permanent ice.

Therefore, over time Pluto collected nitrogen ice in its basins. Ultimately, massive nitrogen ice glaciers have formed on the planet’s surface. As a result, one particularly large glacier has formed Pluto’s most infamous, and loving feature, its heart.

Pluto’s Heart Explained: The future

Finally, how will Pluto’s heart change over time? After all, everything we observe in space either has – or will change over millions, or billions of years.

Actually, using New Horizons data, astronomers have created a simulation of Pluto’s history over the last 50,000 years (seen below).

Photo: Tanguy Bertrand

Finally, data shows us something truly amazing, and endearing happening over time. As nitrogen glaciers expand and contract repeatedly over time, the heart grows and shrinks, like a beating heart. Pluto, we love you back!