PlutoPluto nearly fills the frame in this image from the Long Range Reconnaissance Imager (LORRI) aboard NASA’s New Horizons spacecraft, taken on July 13, 2015, when the spacecraft was 476,000 miles (768,000 kilometers) from the surface. This is the last and most detailed image sent to Earth before the spacecraft’s closest approach to Pluto on July 14. The color image has been combined with lower-resolution color information from the Ralph instrument that was acquired earlier on July 13. This view is dominated by the large, bright feature informally named the “heart,” which measures approximately 1,000 miles (1,600 kilometers) across. The heart borders darker equatorial terrains, and the mottled terrain to its east (right) are complex. However, even at this resolution, much of the heart’s interior appears remarkably featureless—possibly a sign of ongoing geologic processes. Credits: NASA/APL/SwRI

By Seth Shostak, Senior Astronomer and Director of the Center for SETI Research

It made it.

At 4:49 am Pacific Time, July 14, the New Horizons spacecraft slid by Pluto’s mottled orb and headed deeper into the voids of the Solar System.  The flyby’s closest approach lasted only three minutes. 

It was a moment of well-deserved celebration for a team that has labored for a decade to make a reconnaissance of this principal member of the Kuiper Belt of icy objects.  You can read about the SETI Institute’s participation in the mission here.

When New Horizons was launched, Pluto was still a card-carrying planet.  It lost that designation in a vote by the International Astronomical Union in 2006, although the controversy about nomenclature continues to simmer.

While higher resolution images and other data from the spacecraft are still to come, the early images already show an intriguing topography.  Craters in some areas date back billions of years.  These regions are old, and are witness to the Solar System’s early days. 

But there are also unblemished features, such as the huge, white “heart” in the northern hemisphere.  This albino artifact is roughly the size of Texas, and the fact that it is free of craters shows that, geologically speaking, it’s relatively young.  Pluto, despite its small size and frigid circumstances, is clearly not an inert ball of rock and ice but is still changing. 

The data from New Horizons – sent 3 billion miles back to Earth on a low bandwidth link – will continue to pour in.  It’s anticipated that a day after the flyby, images with ten times greater detail will be received.