After almost 10 years and a more that 3 billion mile journey to Pluto… The latest updates from the NASA New Horizon’s probe have revealed some interesting formations on the dwarf planet. The above image, that was taken at 476,000 miles from the surface using the Long Range Reconnaissance Imager (LORRI) aboard the spacecraft, is the last image we will see prior to the closest approach tomorrow. The colour is revealed by combining lower-resolution colour information from the Ralph instrument also on board the spacecraft. Appropriately, the bright shape has been termed “heart”and measures approximately 1,000 miles wide. This region borders with darker terrains on either side, and the mottled terrain to its right (east) – at this resolution, much of the heart’s interior appears featureless, although we keenly await the post-flyby date for a closer look.

In addition to the heart, other features of Pluto geology is proving to be an intriguing new world with distinct surface features, including an immense dark band known as the “whale”, as well as linear polygonal features; a complex band of terrain stretching across the planet that may be cliffs, as well as a circular feature that could be an impact crater. The grey area just above the whale’s “tail” feature is causing particular excitement for New Horizons program scientist Curt Niebur who said “It’s a unique transition region with a lot of dynamic processes interacting, which makes it of particular scientific interest.”

New Horizons has also answered one of the long-asked questions about Pluto: How big is this dwarf planet? Analysis from LORRI revealed that Pluto is 1,473 miles in diameter, which is slightly larger than previous estimates, and confirms that Pluto is larger than all other known solar system objects beyond the orbit of Neptune. This result also tell us that Pluto’s density is slightly lower than previously thought, and the lowest layer of Pluto’s atmosphere (the troposphere) is shallower than previously believed.

In comparison, Pluto’s largest moon, Charon, lacks a substantial atmosphere, and its diameter was easier to determine using ground-based telescopes, however New Horizons has confirmed the previous estimation of Charon’s size of 751 miles across – roughly half that of Pluto. However, new data is revealing Charon’s geology including a system of chasms, larger than the Grand Canyon. This feature is trailed by a large equatorial impact crater, which is ringed by bright rays of ejected material.

With only a few hours to go until New Horizon’s whizzes past Pluto at 30,800 miles per hour, we’re excited to see the detailed features of Pluto final revealed as well as analysis of it’s atmosphere and composition.

You can follow the path of the spacecraft over coming days with a visualization of the actual trajectory data, using NASA’s online Eyes on Pluto