Free Newsletters - Space - Defense - Environment - Energy - Solar - Nuclear
..
. 24/7 Space News .




MERCURY RISING
Mercury contracted more than prior estimates
by Staff Writers
Cleveland OH (SPX) Mar 18, 2014


File image.

New evidence gathered by NASA's MESSENGER spacecraft at Mercury indicates the planet closest to the sun has shrunk up to 7 kilometers in radius over the past 4 billion years, much more than earlier estimates.

The new finding, published in the journal Nature Geoscience Sunday, March 16, solves an apparent enigma about Mercury's evolution.

Older images of surface features indicated that, despite cooling over its lifetime, the rocky planet had barely shrunk at all. But modeling of the planet's formation and aging could not explain that finding.

Now, Paul K. Byrne and Christian Klimczak at the Carnegie Institution of Washington have led a team that used MESSENGER's detailed images and topographic data to build a comprehensive map of tectonic features. That map suggests Mercury shrunk substantially as it cooled, as rock and metal that comprise its interior are expected to.

"With MESSENGER, we have now obtained images of the entire planet at high resolution and, crucially, at different angles to the sun that show features Mariner 10 could not in the 1970s," said Steven A. Hauck, II, a professor of planetary sciences at Case Western Reserve University and the paper's co-author.

Mariner 10, the first spacecraft sent to explore Mercury, gathered images and data over just 45% of the surface during three flybys in 1974 and 1975. MESSENGER, which launched in 2004 and was inserted into orbit in 2011, continues collecting scientific data, completing its 2,900th orbit of Mercury later this month.

Mercury's surface differs from Earth's in that its outer shell, called the lithosphere, is made up of one tectonic plate instead of multiple plates.

To help gauge how the planet may have shrunk, the researchers looked at tectonic features, called lobate scarps and wrinkle ridges, which result from interior cooling and surface compression. The features resemble long ribbons from above, ranging from 5 to more than 550 miles long.

Lobate scarps are cliffs caused by thrust faults that have broken the surface and reach up to nearly 2 miles high. Wrinkle ridges are caused by faults that don't extend as deep and tend to have lower relief. Surface materials from one side of the fault ramp up and fold over, forming a ridge. The scientists mapped a total of 5,934 of the tectonic features.

The scarps and ridges have much the same effect as a tailor making a series of tucks to take in the waist of a pair of pants.

With the new data, the researchers were able to see a greater number of these faults and estimate the shortening across broad sections of the surface and thus estimate the decrease in the planet's radius.

They estimate the planet has contracted between 4.6 and 7 kilometers in radius.

"This is significantly greater than the 1 to maybe 2 kilometers reported earlier on the basis of Mariner 10 data," Hauck said.

And, importantly, he said, models built on the main heat-producing elements in planetary interiors, as detected by MESSENGER, support contraction in the range now documented.

One striking aspect of the form and distribution of surface tectonic features on Mercury is that they are largely consistent with some early explanations about the features of Earth's surface, before the theory of plate tectonics made them obsolete-at least for Earth, Hauck said.

So far, Earth is the only planet known to have tectonic plates instead of a single, outer shell.

The findings, therefore, can provide limits and a framework to understand how planets cool-their thermal, tectonic and volcanic history. So, by looking at Mercury, scientists learn not just about planets in our solar system, but about the increasing number of rocky planets being found around other stars.

.


Related Links
Case Western Reserve University
News Flash at Mercury
Mars News and Information at MarsDaily.com
Lunar Dreams and more






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

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




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





MERCURY RISING
Mercury's contraction much greater than thought
Washington DC (SPX) Mar 18, 2014
New global imaging and topographic data from MESSENGER* show that the innermost planet has contracted far more than previous estimates. The results are based on a global study of more than 5,900 geological landforms, such as curving cliff-like scarps and wrinkle ridges, that have resulted from the planet's contraction as Mercury cooled. The findings, published online March 16, 2014, in Nat ... read more


MERCURY RISING
China's Jade Rabbit lunar rover rouses from latest slumber

NASA Releases First Interactive Mosaic of Lunar North Pole

Study on lunar crater counting shows crowdsourcing effective, accurate tool

Spacesuits And Moon Notes Among The Stars At Bonhams NYC Auction

MERCURY RISING
The Exploration of Murray Ridge Continues

Mars Reconnaissance Orbiter Resumes Full Duty

NASA Orbiter Safe After Unplanned Computer Swap

Mars name-a-crater scheme runs into trouble

MERCURY RISING
Astronauts train at Maxwell

ORBITEC and Wisconsin Await Countdown for "VEGGIE" to Space on SpaceX 3

Orion Makes Testing, Integration Strides Ahead of First Launch to Space

Global patent filings jump 5.1% in 2013: WIPO

MERCURY RISING
Tiangong's New Mission

"Space Odyssey": China's aspiration in future space exploration

China to launch first "space shuttle bus" this year

China expects to launch cargo ship into space around 2016

MERCURY RISING
ESA astronaut Thomas Pesquet will fly to the ISS in 2016

Russian Progress Spacecraft Boosts ISS Orbit

Japanese astronaut becomes ISS commander

Station Crew Preps for Return to Earth, Repairs Recycling System

MERCURY RISING
Proton-M with two Russian communication satellites on board blasts off from Baikonur

Proton-M carrier rocket with two satellites abroad installed on Baikonur launch pad

Lockheed Martin Commercial Launch Services Announces Industry-Unique "Refund Or Reflight" Program

ASTRA 5B delivered for integration on Ariane 5 launcher

MERCURY RISING
UK joins the planet hunt with Europe's PLATO mission

X-ray laser FLASH spies deep into giant gas planets

Crashing Comets Explain Surprise Gas Clump Around Young Star

Every red dwarf star has at least one planet

MERCURY RISING
Heat-Based Technique Offers New Way to Measure Microscopic Particles

ISS dodges space junk

3D X-ray Film: Rapid Movements in Real Time

Reducing debris threat from satellite batteries




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - 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. 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 All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.