Subscribe to our free daily newsletters
. 24/7 Space News .




Subscribe to our free daily newsletters



EXO WORLDS
An Orbital Dance May Help Preserve Oceans on Icy Worlds
by Bill Steigerwald and Nancy Jones for GSFC News
Pasadena CA (JPL) Dec 05, 2017


This composite of enhanced color images of Pluto (lower right) and Charon (upper left), was taken by NASA's New Horizons spacecraft as it passed through the Pluto system on July 14, 2015. This image highlights the striking differences between Pluto and Charon. The color and brightness of both Pluto and Charon have been processed identically to allow direct comparison of their surface properties, and to highlight the similarity between Charon's polar red terrain and Pluto's equatorial red terrain. Pluto and Charon are shown with approximately correct relative sizes, but their true separation is not to scale. The image combines blue, red and infrared images taken by the spacecraft's Ralph/Multispectral Visual Imaging Camera (MVIC).

Heat generated by the gravitational pull of moons formed from massive collisions could extend the lifetimes of liquid water oceans beneath the surface of large icy worlds in our outer solar system, according to new NASA research. This greatly expands the number of locations where extraterrestrial life might be found, since liquid water is necessary to support known forms of life and astronomers estimate there are dozens of these worlds.

"These objects need to be considered as potential reservoirs of water and life," said Prabal Saxena of NASA's Goddard Space Flight Center in Greenbelt, Maryland, lead author of the research published in Icarus November 24. "If our study is correct, we now may have more places in our solar system that possess some of the critical elements for extraterrestrial life."

These frigid worlds are found beyond the orbit of Neptune and include Pluto and its moons. They are known as Trans-Neptunian Objects (TNOs) and are far too cold to have liquid water on their surfaces, where temperatures are less than 350 degrees below zero Fahrenheit (below minus 200 Celsius).

However, there is evidence that some may have layers of liquid water beneath their icy crusts. In addition to bulk densities that are similar to other bodies suspected to have subsurface oceans, an analysis of the light reflected from some TNOs reveals signatures of crystalline water ice and ammonia hydrates.

At the extremely low surface temperatures on these objects, water ice takes a disordered, amorphous form instead of the regularly ordered crystals typical in warmer areas, such as snowflakes on Earth. Also, space radiation converts crystalline water ice to the amorphous form and breaks down ammonia hydrates, so they are not expected to survive long on TNO surfaces. This suggests that both compounds may have come from an interior liquid water layer that erupted to the surface, a process known as cryovolcanism.

Most of the long-lived heat inside TNOs comes from the decay of radioactive elements that were incorporated into these objects as they formed. This heat can be enough to melt a layer of the icy crust, generating a subsurface ocean and perhaps maintaining it for billions of years.

But as the radioactive elements decay into more stable ones, they stop releasing heat and the interiors of these objects gradually cool, and any subsurface oceans will eventually freeze. However, the new research found that the gravitational interaction with a moon can generate enough additional heat inside a TNO to significantly extend the lifetime of a subsurface ocean.

The orbit of any moon will evolve in a gravitational "dance" with its parent object to achieve the most stable state possible - circular, aligned with the equator of its parent, and with the moon spinning at a rate where the same side always faces its parent. Large collisions between celestial objects can generate moons when material is splashed into orbit around the larger object and coalesces into one or more moons under its own gravity.

Since collisions occur in a huge variety of directions and speeds, they are unlikely to produce moons with perfectly stable orbits initially. As a collision-generated moon adjusts to a more stable orbit, mutual gravitational attraction causes the interiors of the parent world and its new moon to repeatedly stretch and relax, generating friction that releases heat in a process known as tidal heating.

The team used the equations for tidal heating and calculated its contribution to the "heat budget" for a wide variety of discovered and hypothetical TNO-moon systems, including the Eris-Dysnomia system. Eris is second-largest of the currently known TNOs after Pluto.

"We found that tidal heating can be a tipping point that may have preserved oceans of liquid water beneath the surface of large TNOs like Pluto and Eris to the present day," said Wade Henning of NASA Goddard and the University of Maryland, College Park, a co-author of the study.

"Crucially, our study also suggests that tidal heating could make deeply buried oceans more accessible to future observations by moving them closer to the surface," said Joe Renaud of George Mason University, Fairfax, Virginia, a co-author on the paper. "If you have a liquid water layer, the additional heat from tidal heating would cause the next adjacent layer of ice to melt."

Although liquid water is necessary for life, it is not enough by itself. Life also needs a supply of chemical building blocks and a source of energy. Deep under the ocean on Earth, certain geologically active places have entire ecosystems that thrive in total darkness because hydrothermal vents called "black smokers" supply the needed ingredients in the form of energy-rich chemicals dissolved in superheated water. Tidal heating or heat from the decay of radioactive elements could both create such hydrothermal vents, according to the team.

The team would like to develop and use even more accurate models of tidal heating and TNO interiors to determine how long tidal heating can extend the lifetime of a liquid water ocean and how the orbit of a moon evolves as tidal heating dissipates energy. The team would also like to discover at what point a liquid water ocean forms; whether it forms almost immediately or if it requires a significant buildup of heat first.

The research was funded by the NASA Postdoctoral Program, managed by the Universities Space Research Association, Columbia, Maryland, as well as the NASA Outer Planets Research Program grant NNX14AR42G. The research was conducted in collaboration with the Sellers Exoplanet Environments Collaboration at NASA Goddard.

EXO WORLDS
Newly Discovered Twin Planets Could Solve Puffy Planet Mystery
Honolulu HI (SPX) Nov 30, 2017
Since astronomers first measured the size of an extrasolar planet 17 years ago, they have struggled to answer the question: how did the largest planets get to be so large? Thanks to the recent discovery of twin planets by a University of Hawaii Institute for Astronomy team led by graduate student Samuel Grunblatt, we are getting closer to an answer. Gas giant planets are primarily made out ... read more

Related Links
Solar System and Beyond
Lands Beyond Beyond - extra solar planets - news and science
Life Beyond Earth


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

Comment using your Disqus, Facebook, Google or Twitter login.

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

EXO WORLDS
Building for a future in space: An interview with Dava Newman and Gui Trotti

Space Farms: 'Mark Watney in The Martian Was Right to Add Poop to the Soil'

NASA successfully fires Voyager 1 thrusters after 37 years

Does the Outer Space Treaty at 50 need a rethink

EXO WORLDS
ISRO eyes one rocket launch a month in 2018

Russia to build launch pad for super heavy-lift carrier by 2028

Flat-Earther's self-launch plan hits a snag

Mechanisms are critical to all space vehicles

EXO WORLDS
EU exempts fuel for ExoMars mission from Russian sanctions

Winter wanderings put Opportunity at 28 Miles on the odometer

Earthworms can reproduce in Mars-like soil

Opportunity Greets Winter Solstice

EXO WORLDS
Nation 'leads world' in remote sensing technology

China plans for nuclear-powered interplanetary capacity by 2040

China plans first sea based launch by 2018

China's reusable spacecraft to be launched in 2020

EXO WORLDS
Going green to the Red Planet

Orbital ATK purchase by Northrop Grumman approved by shareholders

UK space launch program receives funding boost from Westminster

Need to double number of operational satellites: ISRO chief

EXO WORLDS
New catalyst controls activation of a carbon-hydrogen bond

New 3-D printer is 10 times faster than commercial counterparts

Device could reduce the carbon footprint of ethylene production

Researchers inadvertently boost surface area of nickel nanoparticles for catalysis

EXO WORLDS
Scientists identify key factors that help microbes thrive in harsh environments

Exoplanet Has Smothering Stratosphere Without Water

Scientists study Earth's earliest life forms in Nevada hot spring

The answer to planetary habitability is blowing in the stellar wind

EXO WORLDS
Jupiter Blues

Pluto's hydrocarbon haze keeps dwarf planet colder than expected

Jupiter's Stunning Southern Hemisphere

Watching Jupiter's multiple pulsating X-ray Aurora




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