Planetology Archives » Page 8 of 59

November 5th, 2015

NASA Mission Reveals Speed of Solar Wind Stripping Martian Atmosphere

NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) mission has identified the process that appears to have played a key role in the transition of the Martian climate from an early, warm and wet environment that might have supported surface life to the cold, arid planet Mars is today.

MAVEN data have enabled researchers to determine the rate at which the Martian atmosphere currently is losing gas to space via stripping by the solar wind. The findings reveal that the erosion of Mars’ atmosphere increases significantly during solar storms. The scientific results from the mission appear in the Nov. 5 issues of the journals Science and Geophysical Research Letters.

“Mars appears to have had a thick atmosphere warm enough to support liquid water which is a key ingredient and medium for life as we currently know it,” said John Grunsfeld, astronaut and associate administrator for the NASA Science Mission Directorate in Washington. “Understanding what happened to the Mars atmosphere will inform our knowledge of the dynamics and evolution of any planetary atmosphere. Learning what can cause changes to a planet’s environment from one that could host microbes at the surface to one that doesn’t is important to know, and is a key question that is being addressed in NASA’s journey to Mars.”

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Posted by tourdemars to: MAVEN, Planetology

October 27th, 2015

SwRI scientists predict that rocky planets formed from ‘pebbles’

Using a new process in planetary formation modeling, where planets grow from tiny bodies called “pebbles,” Southwest Research Institute scientists can explain why Mars is so much smaller than Earth. This same process also explains the rapid formation of the gas giants Jupiter and Saturn, as reported earlier this year.

“This numerical simulation actually reproduces the structure of the inner solar system, with Earth, Venus, and a smaller Mars,” said Hal Levison, an Institute scientist at the SwRI Planetary Science Directorate. He is the first author of a new paper published in theProceedings of the National Academy of Sciences of the United States (PNAS) Early Edition.

The fact that Mars has only 10 percent of the mass of the Earth has been a long-standing puzzle for solar system theorists. In the standard model of planet formation, similarly sized objects accumulate and assimilate through a process called accretion; rocks incorporated other rocks, creating mountains; then mountains merged to form city-size objects, and so on. While typical accretion models generate good analogs to Earth and Venus, they predict that Mars should be of similar-size, or even larger than Earth. Additionally, these models also overestimate the overall mass of the asteroid belt.

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Posted by tourdemars to: Planetology

October 15th, 2015

Did Mars once have rivers? Pebbles say yes.

Researchers have used the shape of rounded Martian pebbles to extrapolate how far they must have traveled down an ancient riverbed on the Red Planet. The analysis suggests they moved approximately 30 miles (50 kilometers), indicating that Mars once had an extensive river system.

The shape of some Martian pebbles suggests these rocks once rolled dozens of miles down a river, hinting that ancient Martian waterways were stable and not merely ephemeral streams, researchers say.

NASA’s Mars rover Curiosity discovered the small, round stones near its landing site in Gale Crater on the Red Planet in 2013. Researchers previously determined that these stones resemble those found in rivers on Earth, which become round as they slide, roll and hop down riverbeds and scrape other rocks.

Now, a new study suggests the Martian rocks rolled in the river for quite a while — a finding that should help scientists reconstruct what ancient Mars was like and shed light on the Red Planet’s past potential to support life, study team members said.

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Posted by tourdemars to: Life on Mars, Mars Science Laboratory, Planetology

October 8th, 2015

NASA’s Curiosity Rover Team Confirms Ancient Lakes on Mars

http://www.jpl.nasa.gov/spaceimages/images/largesize/PIA19839_hires.jpg

Strata at Base of Mount Sharp

A new study from the team behind NASA’s Mars Science Laboratory/Curiosity has confirmed that Mars was once, billions of years ago, capable of storing water in lakes over an extended period of time.

Using data from the Curiosity rover, the team has determined that, long ago, water helped deposit sediment into Gale Crater, where the rover landed more than three years ago. The sediment deposited as layers that formed the foundation for Mount Sharp, the mountain found in the middle of the crater today.

“Observations from the rover suggest that a series of long-lived streams and lakes existed at some point between about 3.8 to 3.3 billion years ago, delivering sediment that slowly built up the lower layers of Mount Sharp,” said Ashwin Vasavada, Mars Science Laboratory project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, and co-author of the new Science article to be published Friday, Oct. 9.

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Posted by tourdemars to: Life on Mars, Mars Science Laboratory, Planetology, Reconnaissance Orbiter

September 28th, 2015

NASA Confirms Evidence That Liquid Water Flows on Today’s Mars

New findings from NASA’s Mars Reconnaissance Orbiter (MRO) provide the strongest evidence yet that liquid water flows intermittently on present-day Mars. Using an imaging spectrometer on MRO, researchers detected signatures of hydrated minerals on slopes where mysterious streaks are seen on the Red Planet. These darkish streaks appear to ebb and flow over time. They darken and appear to flow down steep slopes during warm seasons, and then fade in cooler seasons. They appear in several locations on Mars when temperatures are above minus 10 degrees Fahrenheit (minus 23 Celsius), and disappear at colder times.
“Our quest on Mars has been to ‘follow the water,’ in our search for life in the universe, and now we have convincing science that validates what we’ve long suspected,” said John Grunsfeld, astronaut and associate administrator of NASA’s Science Mission Directorate in Washington. “This is a significant development, as it appears to confirm that water — albeit briny — is flowing today on the surface of Mars.”

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Posted by tourdemars to: Life on Mars, Planetology, Reconnaissance Orbiter

September 28th, 2015

LIVE NOW: Major Mars mystery revealed!

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Posted by tourdemars to: Planetology

September 14th, 2015

Terraced Craters: Windows Into Mars’ Icy Past

It was a “crazy-looking crater” on the face of Mars that caught Ali Bramson’s eye. But it was a simple calculation that explained the crater’s strange shape.

Combining data gleaned from two powerful instruments aboard NASA’s Mars Reconnaissance Orbiter, or MRO, Bramson and her colleagues determined why the crater is terraced — not bowl shaped, like most craters of this size.

“Craters should be bowl shaped, but this one had terraces in the wall,” says Bramson, a graduate student in the University of Arizona’s Lunar and Planetary Laboratory, or LPL.

Terraces can form when there are layers of different materials in the planet’s subsurface, such as dirt, ice or rock.

“When the crater is forming, the shock wave from an object hitting a planet’s surface propagates differently depending on what substrates are beneath the area of impact,” Bramson says. “If you have a weaker material in one layer, the shock wave can push out that material more easily, and the result is terracing at the interface between the weaker and stronger materials.”

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Posted by tourdemars to: Planetology, Reconnaissance Orbiter

July 16th, 2015

Curiosity rover finds evidence of Mars’ primitive continental crust Los Alamos National Laboratory

The ChemCam laser instrument on NASA’s Curiosity rover has turned its beam onto some unusually light-colored rocks on Mars, and the results are surprisingly similar to Earth’s granitic continental crust rocks. This is the first discovery of a potential “continental crust” on Mars.

“Along the rover’s path we have seen some beautiful rocks with large, bright crystals, quite unexpected on Mars” said Roger Wiens of Los Alamos National Laboratory, lead scientist on the ChemCam instrument. “As a general rule, light-colored crystals are lower density, and these are abundant in igneous rocks that make up the Earth’s continents.”

Mars has been viewed as an almost entirely basaltic planet, with igneous rocks that are dark and relatively dense, similar to those forming the Earth’s oceanic crust, Wiens noted. However, Gale crater, where the Curiosity rover landed, contains fragments of very ancient igneous rocks (around 4 billion years old) that are distinctly light in color, which were analyzed by the ChemCam instrument.

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Posted by tourdemars to: Mars Science Laboratory, Planetology

June 23rd, 2015

Nathalie Cabrol: How Mars might hold the secret to the origin of life TED Talks

While we like to imagine little green men, it’s far more likely that life on other planets will be microbial. Planetary scientist Nathalie Cabrol takes us inside the search for microbes on Mars, a hunt which counterintuitively leads us to the remote lakes of the Andes mountains. This extreme environment — with its thin atmosphere and scorched land — approximates the surface of Mars about 3.5 billion years ago. How microbes adapt to survive here may just show us where to look on Mars — and could help us understand why some microbial pathways lead to civilization while others are a dead end.

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Posted by tourdemars to: Life on Mars, Planetology

June 5th, 2015

The echo of meteorite impacts could tell us what’s inside Mars TechRadar

We’re told to never judge a book by its cover, but it’s apparently fine to judge what lies inside Mars by listening to the echoes of meteorite impacts.

We know very little about the interior of the Red Planet. We know that once it had a global magnetic field and active volcanoes, but it’s unclear if the core is still molten or not. If it is, plate tectonics and earthquakes (which are called marsquakes on Mars) are a possibility.

To find out, the next spacecraft to arrive on Mars will come equipped with precise seismometers to detect tremors. The InSight Lander will listen carefully for seismic waves caused by meteorites, and use the data to make some educated guesses at what materials it passed through along the way.

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Posted by tourdemars to: InSight, Meteorites, Planetology