New gravity map suggests Mars has a porous crustSeptember 13, 2017
NASA scientists have found evidence that Mars' crust is not as dense as previously thought, a clue that could help researchers better understand the Red Planet's interior structure and evolution.
A lower density likely means that at least part of Mars' crust is relatively porous. At this point, however, the team cannot rule out the possibility of a different mineral composition or perhaps a thinner crust.
"The crust is the end-result of everything that happened during a planet's history, so a lower density could have important implications about Mars' formation and evolution," said Sander Goossens of NASA's Goddard Space Flight Center in Greenbelt, Maryland. Goossens is the lead author of a Geophysical Research Letters paper describing the work.
The researchers mapped the density of the Martian crust, estimating the average density is 2,582 kilograms per meter cubed (about 161 pounds per cubic foot). That's comparable to the average density of the lunar crust. Typically, Mars' crust has been considered at least as dense as Earth's oceanic crust, which is about 2,900 kilograms per meter cubed (about 181 pounds per cubic foot).
The new value is derived from Mars' gravity field, a global model that can be extracted from satellite tracking data using sophisticated mathematical tools. The gravity field for Earth is extremely detailed, because the data sets have very high resolution. Recent studies of the Moon by NASA's Gravity Recovery and Interior Laboratory, or GRAIL, mission also yielded a precise gravity map.
The data sets for Mars don't have as much resolution, so it's more difficult to pin down the density of the crust from current gravity maps. As a result, previous estimates relied more heavily on studies of the composition of Mars' soil and rocks.
"As this story comes together, we're coming to the conclusion that it's not enough just to know the composition of the rocks," said Goddard planetary geologist Greg Neumann, a co-author on the paper. "We also need to know how the rocks have been reworked over time."
Goossens and colleagues started with the same data used for an existing gravity model but put a new twist on it by coming up with a different constraint and applying it to obtain the new solution. A constraint compensates for the fact that even the best data sets can't capture every last detail. Instead of taking the standard approach, known to those in the field as the Kaula constraint, the team created a constraint that considers the accurate measurements of Mars' elevation changes, or topography.
"With this approach, we were able to squeeze out more information about the gravity field from the existing data sets," said Goddard geophysicist Terence Sabaka, the second author on the paper.
Before taking on Mars, the researchers tested their approach by applying it to the gravity field that was in use before the GRAIL mission. The resulting estimate for the density of the moon's crust essentially matched the GRAIL result of 2,550 kilograms per meter cubed (about 159 pounds per cubic foot).
From the new model, the team generated global maps of the crust's density and thickness. These maps show the kinds of variations the researchers expect, such as denser crust beneath Mars' giant volcanoes.
The researchers note that NASA's InSight mission -- short for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport -- is expected to provide the kinds of measurements that could confirm their finding. This Discovery Program mission, scheduled for launch in 2018, will place a geophysical lander on Mars to study its deep interior.
For more about NASA's Mars explorations, visit: http://www.nasa.gov/mars
NASA/Goddard Space Flight Center
Related Mars Articles:
Heavy rain on Mars reshaped the planet's impact craters and carved out river-like channels in its surface billions of years ago, according to a new study published in Icarus.
Purdue researchers developed a model that suggests that debris that was pushed into space from an asteroid or other body slamming into Mars around 4.3 billion years ago and alternates between becoming a planetary ring and clumping up to form a moon.
Scientists continue to unravel the mystery of life on Mars by investigating evidence of water in the planet's soil.
Researchers have discovered a type of dune on Mars intermediate in size between tiny ripples and wavier dunes, and unlike anything seen on Earth.
Radar measurements of Mars' polar ice caps reveal that the mostly dry, dusty planet is emerging from an ice age, following multiple rounds of climate change.
University of Iowa researchers have a $501,000 NASA grant to travel to Iceland to better understand sand dunes found all over the planet Mars.
A team of world-class CIP and NASA scientists will grow potatoes under Martian conditions in a bid to save millions of lives.
Scientists at Washington State University and the University of Idaho are helping students figure out how to farm on Mars, much like astronaut Mark Watney, played by Matt Damon, attempts in the critically acclaimed movie 'The Martian.'
An international team of researchers has for the first time predicted the occurrence of aurorae visible to the naked eye on a planet other than Earth.
Researchers have long known that there is water in the form of ice on Mars.
Related Mars Reading:
Mars: Our Future on the Red Planet
by Leonard David (Author), Ron Howard (Foreword)
The next frontier in space exploration is Mars, the red planet—and human habitation of Mars isn’t much farther off. Now the National Geographic Channel goes years fast-forward with “Mars,” a six-part series documenting and dramatizing the next 25 years as humans land on and learn to live on Mars. This companion book to the series explores the science behind the mission and the challenges awaiting those brave individuals. Filled with vivid photographs taken on Earth, in space, and on Mars; arresting maps; and commentary from the world’s top planetary scientists, this fascinating... View Details
Packing for Mars: The Curious Science of Life in the Void
by Mary Roach (Author)
“America’s funniest science writer” (Washington Post) returns to explore the irresistibly strange universe of life without gravity in this New York Times bestseller.Space is a world devoid of the things we need to live and thrive: air, gravity, hot showers, fresh produce, privacy, beer. Space exploration is in some ways an exploration of what it means to be human. How much can a person give up? How much weirdness can they take? What happens to you when you can’t walk for a year? have sex? smell flowers? What happens if you vomit in your... View Details
How We'll Live on Mars (TED Books)
by Stephen Petranek (Author)
Award-winning journalist Stephen Petranek says humans will live on Mars by 2027. Now he makes the case that living on Mars is not just plausible, but inevitable.
It sounds like science fiction, but Stephen Petranek considers it fact: Within twenty years, humans will live on Mars. We’ll need to. In this sweeping, provocative book that mixes business, science, and human reporting, Petranek makes the case that living on Mars is an essential back-up plan for humanity and explains in fascinating detail just how it will happen.
The race is on. Private companies, driven by... View Details
Life on Mars: Poems
by Tracy K. Smith (Author)
Winner of the 2012 Pulitzer Prize
* Poet Laureate of the United States *
* A New York Times Notable Book of 2011 and New York Times Book Review Editors' Choice *
* A New Yorker, Library Journal and Publishers Weekly Best Book of the Year *
New poetry by the award-winning poet Tracy K. Smith, whose "lyric brilliance and political impulses never falter" (Publishers Weekly, starred review)
You lie there kicking like a baby, waiting for God himself
To lift you past the rungs of your... View Details
The Case for Mars: The Plan to Settle the Red Planet and Why We Must
by Robert Zubrin (Author), Arthur C. Clarke (Foreword), Richard Wagner (Foreword)
Since the beginning of human history, Mars has been an alluring dream—the stuff of legends, gods, and mystery. The planet most like ours, it has still been thought impossible to reach, let alone explore and inhabit. But all that changed when leading space exploration authority Robert Zubrin crafted a daring new blueprint, Mars Direct. When it was first published in 1996, The Case for Mars became an instant classic, lauded widely for its game-changing perspective by those who would see the American space program rise to the challenge of Mars; Carl Sagan called Zubrin the man who,... View Details
Red Mars (Mars Trilogy)
by Kim Stanley Robinson (Author)
Winner of the Nebula Award for Best Novel • Soon to be a series on Spike TV
Discover the novel that launched one of science fiction’s most beloved, acclaimed, and awarded trilogies: Kim Stanley Robinson’s masterly near-future chronicle of interplanetary colonization.
For centuries, the barren, desolate landscape of the red planet has beckoned to humankind. Now a group of one hundred colonists begins a mission whose ultimate goal is to transform Mars into a more Earthlike planet. They will place giant satellite mirrors in Martian orbit to... View Details
Mars: The Red Planet: Rocks, Rovers, Pioneers, and More!
by Elizabeth Carney (Author)
Budding scientists and kids curious about Earth's next-door neighbor can blast off to the red planet! This highly visual book will cover all kinds of topics, from extreme weather to high-tech rovers to plans for a human colony on Mars. Complete with up-to-date facts about water and all the latest discoveries, Mars: The Red Planet comes at an exciting time for space exploration. View Details
Welcome to Mars: Making a Home on the Red Planet (Science & Nature)
by Buzz Aldrin (Author), Marianne Dyson (Author)
Space is still the final frontier and Mars continues to make news and attract generations of young people. In this fascinating book, hero-astronaut Buzz Aldrin challenges curious kids to think about Mars as not just a faraway red planet but as a possible future home for Earthlings! What will your new home be like? How will you get there? What will you eat for breakfast? Find out what life might be like far, far from Earth as you navigate your way through this fun and fascinating book. What kid wouldn't want to blast off with him on this (literary) journey! View Details
The Mighty Mars Rovers: The Incredible Adventures of Spirit and Opportunity (Scientists in the Field Series)
by Elizabeth Rusch (Author)
On June 10, 2003, a little rover named Spirit blasted off on a rocket headed for Mars. On July 7, 2003, a twin rover named Opportunity soared through the solar system with the same mission: to find out if Mars ever had water that could have supported life. A thrilling addition to the acclaimed Scientists in the Field series, The Mighty Mars Rovers tells the greatest space robot adventure of all time through the eyes—and heart—of Steven Squyres, professor of astronomy at Cornell University and lead scientist on the mission.
This suspenseful page-turner captures the... View Details