New Horizons scientists reveal disastrous reason for Pluto's crater-free Sputnik Planum

Contributed by
Jan 7, 2016, 12:02 PM EST (Updated)

In an oft-cited standard of measurement utilized to describe doomsday space rocks, NASA scientists have revealed that an impact by a meteor the "size of Manhattan" may explain the icy, crater-free zone of Pluto the New Horizons team unofficially named Sputnik Planum.

New Horizons Principal Investigator Alan Stern delivered an updated Pluto science presentation at the 227th meeting of the American Astronomical Society in Kissimmee, Fla., on Tuesday, laying out the New Horizon science team’s latest theories on the frozen dwarf planet’s incredibly smooth, patterned ice plains.  Stern said he and his crew believe Sputnik Planum is actually a "large impact basin" most likely punched out by an impactor on the order of 10 kilometers (6.2 miles) across.  ZOMG!  It really IS the size of Manhattan!

Situated in the heart-shaped interior of the Tombaugh Regio area named for the former ninth planet's discoverer, Clyde Tombaugh, and bordered by the jagged line of the al Idrisi mountains, Sputnik Planum is a region of lined ice plains and blocky structures that were probably the result of this violent collision hundreds of millions of years ago, long before the bright plain migrated to its current alignment along Pluto's equator.  

Geologists postulate that the process of "polar wander" observed on Earth and other rocky planets may be the driving dynamic behind this recent discovery.

“[Sputnik Planum] is so large and its volume so great that the negative mass anomaly caused by its impact has very likely caused this object to move to its current position near the equator,” Stern explained.

Stern went on to discuss that the blocky ice structures characteristic of Sputnik Planum are probably the result of deep thermal convection and density differences between different ices.

“Water ice floats in nitrogen ice,” Stern said. “These blocks appear to have been removed from a subsurface layer, and they are now ‘floating’ in a large reservoir.”

A heat source emanating from within Pluto's core could be the culprit in all this thermal convection and glacial flow that continues to transform the terrain, and this new theory from the New Horizons team revolving around an ancient impact may be the best guess yet to explain one of Pluto's biggest mysteries.

“We did not predict that a small planet like Pluto could still be active and would not have completely cooled off,” Stern concluded.


(Via Gizmodo)