New Horizons' Earth-Like Discovery --"The Dunes of Pluto"

Postado Junho 02, 2018

The light gray and whitish bumps were first exposed by NASA's New Horizons space probe in its 2015 flyover.

'Pretty much nowhere else we know of is cold enough.' said Matt Telfer of Plymouth University in England, who published a report in the journal Science detailing the findings.

Thought to be relatively recent, the parallel rows of dunes are in Pluto's heart-shaped region at the base of mountains as tall as the Alps and formed from giant blocks of ice with frosty methane snow caps.

In their study, the researchers explain how they studied pictures of a plain known as Sputnik Planitia, parts of which are covered with what look like fields of dunes. Generally speaking, dunes are sculpted by winds and Pluto's atmosphere, 1,000 times thinner than ours, was thought to be too weak to generate strong enough gusts for this objective. They believe that sublimation, which converts solid nitrogen directly into a gas, results in sand-sized grains of methane being released into the environment. Pluto's mild winds then carried the particles to the area where the dunes on Pluto are now located.

"It turns out that even though there is so little atmosphere, and the surface temperature is around minus 382 degrees Fahrenheit (minus 230 degrees Celsius), we still get dunes forming". "That tells us that the atmosphere works with the surface on Pluto and helps shape it". "We have been focusing on what's close to us, but there's a wealth of information in the distant reaches of the Solar System too". Modelling of environmental conditions on Pluto shows that although the sunlight that falls on Pluto's surface is much weaker than on Earth, it is still sufficient to cause ice at and just below the surface to sublime.

Combining an analysis of wind streak and dune-like features with spectral and numerical modeling, the scientists determined what might be the underlying architect of dunes on Pluto.

Pluto, smaller than Earth's moon with a diameter of about 1,400 miles (2,380 km), orbits roughly 3.6 billion miles (5.8 billion km) away from the sun, nearly 40 times farther than Earth's orbit, with a surface marked by plains, mountains, craters and valleys.

These grains are then transported by Pluto's moderate winds, which can reach between 18 and 25 miles per hour. In comparison with the pressure of Earth's atmosphere, the Pluto's atmosphere has got a lower surface pressure.

This is the sixth place in the solar system where scientists have found dunes.

The study's lead author, Matt Telfer of Plymouth University in the United Kingdom, noted there were dunes on the scorching surface of Venus under a dense atmosphere and in the distant reaches of the solar system at minus 230 degrees Celsius under a thin atmosphere. "Most notably, it remains to be shown how high the dunes are, when they are most active, whether they change and whether entrainment can occur without lofting".

Another discovery: the dunes are probably young, geologically. In just six short months, on New Year's Day 2019, New Horizons will fly past the tiny trans-Neptunian object 2014 MU69, located about a billion miles (1.6 billion km) beyond Pluto.