. 24/7 Space News .
EXO WORLDS
Taking the pulse of an ocean world
by Staff Writers
Tempe AZ (SPX) May 10, 2017


illustration only

Jupiter's moon Europa is definitely an odd place. Discovered in 1610 by Galileo Galilei, it was first seen in detail only in the late 1970s, after spacecraft visited the Jovian system.

Slightly smaller than our own moon, Europa could hardly appear more different. Both have interiors of rock and metal. But Europa is wrapped in a global saltwater ocean and covered by a bright shell of ice. The shell is scarred with cracks and faults and mottled places where the ice has been breached by liquid from below.

Scientists have speculated for decades what lies within that ocean. It is larger in volume than all the oceans of Earth put together.

A NASA-funded seismometer under development at Arizona State University holds the promise of landing on Europa's ice shell - and listening to it.

The seismometer would use Europa's natural tides and other movements to discover the shell's thickness, see whether it holds pockets of water - subsurface lakes - within the ice, and determine how easily, and how often, ocean water could rise and spill out on the surface.

"We want to hear what Europa has to tell us," said Hongyu Yu, of ASU's School of Earth and Space Exploration (SESE). "And that means putting a sensitive 'ear' on Europa's surface."

Exploration systems engineer Yu heads up a team of ASU scientists that includes seismologist Edward Garnero, geophysicist Alyssa Rhoden, and chemical engineer Lenore Dai, director of the School for Engineering of Matter, Transport and Energy in the Ira A. Fulton Schools of Engineering.

Technology Investment
While there are no current plans to send a lander to Europa, the team has received a grant from NASA to develop and test a miniature seismometer no larger than about 4 inches (10 centimeters) on a side, which could be crucial in advancing future Europa exploration. Fittingly, considering where it is being created, the project is titled Seismometers for Exploring the Subsurface of Europa, or SESE.

Most seismometers, whether for use on Earth or other planets, rely on a mass-and-spring sensor concept to detect passing earthquake waves. But that type of seismometer, says Yu, has to be set down in an upright position, it must be put in place carefully with no major jolts or shaking, and the chamber where the sensor operates needs a complete vacuum to ensure accurate measurements.

"Our design avoids all these problems," Yu explains. The SESE seismometer uses a micro-electromechanical system with a liquid electrolyte as the sensor. "This design has a high sensitivity to a wide range of vibrations, and it can operate at any angle to the surface.

"And if necessary," he adds, "they can hit the ground hard on landing." Yu notes that the team tested the prototype by hitting it with a sledgehammer. It survived.

Besides being extremely rugged, the SESE seismometer promises to push ahead the state of the art in sensors as well. "We're excited at the opportunity to develop electrolytes and polymers beyond their traditional temperature limits," says team member Dai. "This project also exemplifies collaboration across disciplines."

Firm Touchdown Needed
The ability to withstand a hard landing is a great help, says team member Garnero. "Seismometers need to connect with the solid ground to operate most effectively." Sitting on loose surface materials can isolate the instrument from seismic waves passing through the body of the moon or planet - or, on Europa, its ice shell.

Landers, which would carry seismometers, "typically have four or six legs," Garnero said. "If each leg carries a seismometer, these could be pushed into the surface on landing, making good contact with the ground."

In addition, he said, having a number of sensors on a lander gives scientists the opportunity to combine the data recorded at each. This lets them overcome the variable seismic vibrations recorded by each instrument, and it allows scientists to tell what direction quake waves come from.

"We can also sort out high frequency signals from longer wavelength ones," Garnero explained. The wider the spectrum the instrument can sense, the more phenomena it will detect. "For example, small meteorites hitting the surface not too far away would produce high frequency waves, and tides of gravitational tugs from Jupiter and Europa's neighbor moons would make long, slow waves."

So what would Europa sound like?
Garnero laughed. "I think we'll hear things that we won't know what they are."

But, he said, "ice being deformed on a local scale would be high in frequency - we'd hear sharp pops and cracks. From ice shell movements on a more planetary scale, I would expect creaks and groans."

Ocean World
Europa can be glimpsed in binoculars from the backyard as it circles Jupiter once every 85 hours. But it's just a point of light, looking no different from what Galileo saw when he discovered it.

The Europa that scientists study today, however, is more properly considered an ocean world. This is because of two flyby spacecraft (NASA's Voyager 1 and 2) and an orbiter (NASA's Galileo) that spent eight years at Jupiter. Long-distance observations of Europa also have come from the Hubble Space Telescope orbiting Earth, which detected plumes of water vapor erupting from the shell in 2012 and 2016.

"At Europa, we're trying to use seismometers to determine where the liquid water lies within the ice shell," team member Rhoden said. "We want to know how active the ice shell is."

The answers to these questions are important to the future exploration of this moon and its habitability, she said. "An active shell with pockets of water creates more niches for life and more ways to transport nutrients from the ocean to the surface."

Locating these pockets on Europa would allow future lander missions to possibly sample ocean water brought up through the ice shell.

Just how active is Europa?
"We don't know," Rhoden said. The surface is geologically young, with an approximate age (based on numbers of craters) of 50 to 100 million years. "It may have undergone an epoch of activity early in that period and then shut down." But it's equally possible, she says, that the shell is experiencing fractures, uplifts, offsets, and melt-throughs today.

"Hubble's recent plume observations last fall appear to support that."

As Europa orbits Jupiter, it gets repeated tugs from the gravity of neighbor moons Io and Ganymede. These tugs keep Europa's orbit from becoming circular and that lets Jupiter stress the shell - and then let it relax - over and over, endlessly. Thus, Rhoden said, seismometers on the surface should detect any ongoing activity in the shell.

The team developing the SESE seismometer has its sights on Europa, but they are also looking beyond, because the design is robust and adaptable. This could let it become something of a universal instrument for seismology on other worlds.

As team leader Yu explains, "With modification to fit local environments, this instrument should work on Venus and Mars, and likely other planets and moons, too."

EXO WORLDS
When a brown dwarf is actually a planetary mass object
Washington DC (SPX) May 10, 2017
Sometimes a brown dwarf is actually a planet-or planet-like anyway. A team led by Carnegie's Jonathan Gagne, and including researchers from the Institute for Research on Exoplanets (iREx) at Universite de Montreal, the American Museum of Natural History, and University of California San Diego, discovered that what astronomers had previously thought was one of the closest brown dwarfs to our own ... read more

Related Links
Arizona State University
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
NASA Receives Proposals for Future Solar System Mission

'Road to Nowhere': Retired Cosmonaut Reveals How It Feels to Walk in Space

Orion Motor Ready for Crewed Mission

Orbiting at 250 Statute Miles, Florida Tech Experiment Tested

EXO WORLDS
Testing Prepares NASA's Space Launch System for Liftoff

GSLV Successfully Launches South Asia Satellite

ISRO Successfully Launches GSAT-9 'SAARC' South Asian Communication Satellite

First Contract under Booster Propulsion Technology Maturation BAA Complete

EXO WORLDS
Seasonal Flows in Valles Marineris

NASA Rover Curiosity Samples Active Linear Dune on Mars

Is Anything Tough Enough to Survive on Mars

Japan aims to uncover how moons of Mars formed

EXO WORLDS
China tests 'Lunar Palace' as it eyes moon mission

China to conduct several manned space flights around 2020

Reach for the Stars: China Plans to Ramp Up Space Flight Activity

China's cargo spacecraft completes in-orbit refueling

EXO WORLDS
AIA report outlines policies needed to boost the US Space Industry competitiveness

Allied Minds' portfolio company BridgeSat raises $6 million in Series A financing

Blue Sky Network Targets Key Markets For Iridium SATCOM Solutions

How Outsourcing Your Satellite Related Services Saves You Time and Money

EXO WORLDS
First luminescent molecular system with a lower critical solution temperature

Space radiation reproduced in the lab for better, safer missions

Stenciling with atoms in 2-dimensional materials possible

High temperature step-by-step process makes graphene from ethene

EXO WORLDS
First SETI Institute Fellows Announced

Taking the pulse of an ocean world

Astrophysicists find that planetary harmonies around TRAPPIST-1 save it from destruction

Two Webb instruments well suited for detecting exoplanet atmospheres

EXO WORLDS
Not So Great Anymore: Jupiter's Red Spot Shrinks to Smallest Size Ever

Waves of lava seen in Io's largest volcanic crater

The PI's Perspective: No Sleeping Back on Earth!

ALMA investigates 'DeeDee,' a distant, dim member of our solar system









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - 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. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.