Sputnik Planitia, the bright plain that forms the left side of Pluto’s heart-shaped region, appears to be wiping away its own record of impacts. The basin, about 1,000 kilometers across and made largely of nitrogen ice, has no visible impact craters on its surface.
For planetary scientists, that missing crater record is a major clue. On many worlds, craters build up over long periods and preserve a surface’s history. If Sputnik Planitia lacks them entirely, it suggests the plain is being resurfaced quickly enough that old scars disappear before many new ones can accumulate.
The leading idea described in the report is that the nitrogen ice is being churned from below and replaced over time. That would mean the plain is not static but geologically restless, with surface material cycling in a way that keeps it looking fresh and young.
The finding adds to the picture of Pluto as a far more active world than once expected. Rather than a frozen body locked in deep time, Pluto appears to host an icy basin whose surface is constantly renewed, erasing evidence of past impacts and reshaping the left lobe of its famous heart.
