Subscribe free to our newsletters via your
. 24/7 Space News .




Subscribe free to our newsletters via your




















OUTER PLANETS
New Perspective on How Pluto's "Icy Heart" Came to Be
by Staff Writers
College Park MD (SPX) Nov 30, 2016


Image courtesy EPA/NASA/APL/SWRI.

Pluto's "icy heart" is a bright, two-lobed feature on its surface that has attracted researchers ever since its discovery by the NASA New Horizons team in 2015. Of particular interest is the heart's western lobe, informally named Sputnik Planitia, a deep basin containing three kinds of ices - frozen nitrogen, methane and carbon monoxide - and appearing opposite Charon, Pluto's tidally locked moon.

Sputnik Planitia's unique attributes have spurred a number of scenarios for its formation, all of which identify the feature as an impact basin, a depression created by a smaller body striking Pluto at extremely high speed.

A new study led by Douglas Hamilton, professor of astronomy at the University of Maryland, instead suggests that Sputnik Planitia formed early in Pluto's history and that its attributes are inevitable consequences of evolutionary processes. The study was published in the journal Nature on December 1, 2016.

"The main difference between my model and others is that I suggest that the ice cap formed early, when Pluto was still spinning quickly, and that the basin formed later and not from an impact," said Hamilton, who is lead author of the paper.

"The ice cap provides a slight asymmetry that either locks toward or away from Charon when Pluto's spin slows to match the orbital motion of the moon."

Using a model he developed, Hamilton found that the initial location of Sputnik Planitia could be explained by Pluto's unusual climate and its spin axis, which is tilted by 120 degrees.

For comparison, Earth's tilt is 23.5 degrees. Modeling the dwarf planet's temperatures showed that when averaged over Pluto's 248-year orbit, the 30 degrees north and south latitudes emerged as the coldest places on the dwarf planet, far colder than either pole. Ice would have naturally formed around these latitudes, including at the center of Sputnik Planitia, which is located at 25 degrees north latitude.

Hamilton's model also showed that a small ice deposit naturally attracts more ices by reflecting away solar light and heat. Temperatures remain low, which attracts more ice and keeps the temperature low, and the cycle repeats.

This positive feedback phenomenon, called the runaway albedo effect, would eventually lead to a single dominating ice cap, like the one observed on Pluto. However, Pluto's basin is significantly larger than the volume of ice it contains today, suggesting that Pluto's heart has been slowly losing mass over time, almost as if it was wasting away.

Even so, the single ice cap represents an enormous weight on Pluto's surface, enough to shift the dwarf planet's center of mass. Pluto's rotation slowed gradually due to gravitational forces from Charon, just as Earth is slowly losing spin under similar forces from its moon.

However, because Charon is so large and so close to Pluto, the process led to Pluto locking one face toward its moon in just a few million years. The large mass of Sputnik Planitia would have had a 50 percent chance of either facing Charon directly or turning as far away from the moon as possible.

"It is like a Vegas slot machine with just two states, and Sputnik Planitia ended up in the latter position, centered at 175 degrees longitude," said Hamilton.

It would also be easy for the accumulated ice to create its own basin, simply by pushing down, according to Hamilton.

"Pluto's big heart weighs heavily on the small planet, leading inevitably to depression," said Hamilton, noting that the same phenomenon happens on Earth: the Greenland Ice Sheet created a basin and pushed down the crust that it rests upon.

While Hamilton's model can explain both the latitude and longitude of Sputnik Planitia, as well as the fact that the ices exist in a basin, several other models were also presented in the December 1, 2016, issue of the journal Nature.

In one of those papers, UC Santa Cruz Professor of Earth and Planetary Sciences Francis Nimmo, Hamilton and their co-authors modeled how Sputnik Planitia may have formed if its basin was caused by an impact, such as the one that created Charon. Their results showed that the basin may have formed after Pluto slowed its rotation, migrating only slightly to its present location. If this late formation scenario proves correct, the properties of Sputnik Planitia may hint at the presence of a subsurface ocean on Pluto.

"Either model is viable under the right conditions," said Hamilton. "While we cannot conclude definitively that there is an ocean under Pluto's icy shell, we also cannot state that there is not one."

Although Pluto was stripped of its status as a planet, an ice cap is a surprisingly Earth-like property. In fact, Pluto is only the third body - Earth and Mars being the others - known to possess an ice cap. The ices of Sputnik Planitia may therefore offer hints relevant to more familiar ices here on Earth.

"The Rapid Formation of Sputnik Planitia Early in Pluto's History," Douglas P. Hamilton; S. A. Stern; J. M. Moore; L. A. Young; and the New Horizons Geology, Geophysics and Imaging Theme Team, 2016 Dec. 1, Nature.


Comment on this article using your Disqus, Facebook, Google or Twitter login.

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

.


Related Links
University of Maryland
The million outer planets of a star called Sol






Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
OUTER PLANETS
Pluto follows its cold, cold heart
Tucson AZ (SPX) Nov 17, 2016
Sputnik Planitia, a 1,000-kilometer wide basin within the iconic heart-shaped region observed on Pluto's surface, could be in its present location because accumulation of ice made the dwarf planet roll over, creating cracks and tensions in the crust that point towards the presence of a subsurface ocean. Published in the Nov. 17 issue of Nature, these are the conclusions of research by Jame ... read more


OUTER PLANETS
Orbital ATK Ends 2016 with Three Successful Cargo Resupply Missions to ISS

Space Food Bars Will Keep Orion Weight Off and Crew Weight On

Russian Space Sector Overcomes Failures

Embry-Riddle Students Join Project PoSSUM to Test Prototype Spacesuits in Zero-G

OUTER PLANETS
Russia to Launch Fewer Spacecraft in 2016 Than US, China for First Time

Soyuz-U Carrier Rocket Installed to Baikonur Launching Pad

Ariane 5's impressive 75 in-a-row launch record

Vega ready for GOKTURK-1A to be encapsulated

OUTER PLANETS
CaSSIS Sends First Images from Mars Orbit

First views of Mars show potential for ESA's new orbiter

ExoMars space programme needs an extra 400 million euros

Opportunity team onsidering a new route due to boulder field

OUTER PLANETS
China launches 4th data relay satellite

Material and plant samples retrieved from space experiments

Chinese astronauts return to earth after longest mission

China completes longest manned space mission yet

OUTER PLANETS
ESA looks at how to catch a space entrepreneur

Two-year extensions confirmed for ESA's science missions

Thales and SENER to jointly supply optical payloads for space missions

Citizens' space debate: the main findings and the future

OUTER PLANETS
Laser-based Navigation Sensor Could Be Standard for Planetary Landing Missions

Bringing silicon to life

British Scientists Develop a 3D Metal Printer That Works in Space

Scientists shrink electron gun to matchbox size

OUTER PLANETS
Biologists watch speciation in a laboratory flask

Life before oxygen

Timing the shadow of a potentially habitable extrasolar planet

Fijian ants began farming 3 million years ago

OUTER PLANETS
New analysis adds to support for a subsurface ocean on Pluto

Pluto follows its cold, cold heart

New Analysis Supports Subsurface Ocean on Pluto

Mystery solved behind birth of Saturn's rings




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement