Recently an organic-rich ocean hiding under the surface of Pluto was detected. Astronomers detected the presence of ammonia mixed in with Pluto’s rusty surface coloration. As researchers have detailed in two new studies, this could have fascinating implications for the icy dwarf planet.
First, that ammonia-tinned ice suggests a salty, organic-rich ocean hiding under the surface of Pluto. One that may contain the right ingredients for life. It also suggests elusive ice volcanoes, drawing water and ammonia from the underground and spraying it all over the surface.
The data comes from New Horizons, the 2015 dwarf planet-flying spacecraft. The instrumentation of the probe was furiously collecting data as it made its closest encounter-including a near-infrared spectrum of the Virgil Fossa, a region deeply tinted with a rich brownish red.
Signatures in the near-infrared spectrum were consistent in some parts with ammonia ice mixed with water ice, and in others, water ice-free ammonia ice.
“This was a huge surprise to us all about Pluto,” said the NASA Ames Research Center’s planetary scientist Dale Cruikshank to Science News. “It means there are plenty of surprises in that part of the Solar System waiting to be uncovered.”
What makes it even more surprising is that in the Solar System, ammonia does not last long (in cosmic terms) out in the open. It is degraded relatively quickly by ultraviolet light and cosmic radiation-we’re talking along millions of years.
Pluto is a billion-year-old, so there must have been something to put it – and also recently.
There is an indication of how ammonia is distributed. It seems to have been sprayed out by several cryovolcanic vents. Volcanoes that erupt volatile liquids like water, methane, and ammonia instead of molten rock.
This adds to the growing body of evidence that supports liquid oceans below the frigid surface of Pluto, which can plummet to -230 degrees Celsius. A paper released earlier this month suggested that a layer of gas trapped under Pluto’s surface ice could isolate the water and keep it from freezing after it was melted by Pluto’s core warmth.
Also Read: The First Ever Molecule Of The Universe
Another piece of the puzzle is the presence of ammonia. It is a natural antifreeze that can lower up to 100 degrees Celsius the freezing point of water. It has long been thought that icy bodies like Pluto might have cryovolcanoes. So it is profoundly rewarding to find supporting evidence for that theory, as well as support for the hypothesized subsurface oceans.
But other implications could be the presence of ammonia. The redness of Pluto is thought to come from molecules known as Tholins, organic compounds that form when ultraviolet or cosmic radiation cooks carbon-containing compounds like methane or carbon dioxide.
The fact that redness appears in conjunction with water and ammonia suggests that organic compounds may also be present in the water.
And laboratory experiments have shown that ultraviolet light irradiating ammonia and organic compounds can produce molecules that create the building blocks of life, such as RNA and DNA nucleobases.
According to Cruikshank and his team in a paper, “The red material associated with the H2O ice may contain nucleobases resulting from energetic processing on the surface or inside Pluto.”
Also Read: Back to Neptune’s icy moon Triton
Does this mean Pluto’s life? Perhaps not. It’s Celsius -230 degrees! But as we get pieces of evidence that are potentially rich in organics for subsurface oceans, it now seems at least slightly possible.
We have no way to know if there are life-giving hydrothermal vents down there on Pluto’s alien seafloor, but with all that ammonia in the water, any life that emerged-if it could-would need some pretty extreme adjustments.