Just over 3 years ago (by planet Earth’s calendar) the Curiosity Mars Rover landed on the Martian surface. The rover has treated us to the most incredible and surreal surface images of the alien world. Here you can see the path of the rover’s wheels as it crosses over a dune.
The top image is recorded under Martian lighting conditions while the bottom features a white balanced version of the Martian surface if it was under the light of Earth’s sky. (Image Credit: NASA/JPL-Caltech/MSSS)
NASA’S CURIOSITY ROVER TEAM CONFIRMS ANCIENT LAKES ON MARS
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.
The findings build upon previous work that suggested there were ancient lakes on Mars, and add to the unfolding story of a wet Mars, both past and present. Last month, NASA scientists confirmed current water flows on Mars.
“What we thought we knew about water on Mars is constantly being put to the test,” said Michael Meyer, lead scientist for NASA’s Mars Exploration Program at NASA Headquarters in Washington. “It’s clear that the Mars of billions of years ago more closely resembled Earth than it does today. Our challenge is to figure out how this more clement Mars was even possible, and what happened to that wetter Mars.”
Before Curiosity landed on Mars in 2012, scientists proposed that Gale Crater had filled with layers of sediments. Some hypotheses were “dry,” suggesting that sediment accumulated from wind-blown dust and sand. Others focused on the possibility that sediment layers were deposited in ancient lakes.
The latest results from Curiosity indicate that these wetter scenarios were correct for the lower portions of Mount Sharp. Based on the new analysis, the filling of at least the bottom layers of the mountain occurred mostly by ancient rivers and lakes over a period of less than 500 million years.
“During the traverse of Gale, we have noticed patterns in the geology where we saw evidence of ancient fast-moving streams with coarser gravel, as well as places where streams appear to have emptied out into bodies of standing water,” Vasavada said. “The prediction was that we should start seeing water-deposited, fine-grained rocks closer to Mount Sharp. Now that we’ve arrived, we’re seeing finely laminated mudstones in abundance that look like lake deposits.”
The mudstone indicates the presence of bodies of standing water in the form of lakes that remained for long periods of time, possibly repeatedly expanding and contracting during hundreds to millions of years. These lakes deposited the sediment that eventually formed the lower portion of the mountain.
“Paradoxically, where there is a mountain today there was once a basin, and it was sometimes filled with water,” said John Grotzinger, the former project scientist for Mars Science Laboratory at the California Institute of Technology in Pasadena, and lead author of the new report. “We see evidence of about 250 feet (75 meters) of sedimentary fill, and based on mapping data from NASA’s Mars Reconnaissance Orbiter and images from Curiosity’s camera, it appears that the water-transported sedimentary deposition could have extended at least 500 to 650 feet (150 to 200) meters above the crater floor.”
Furthermore, the total thickness of sedimentary deposits in Gale Crater that indicate interaction with water could extend higher still, perhaps up to one-half mile (800 meters) above the crater floor.
Above 800 meters, Mount Sharp shows no evidence of hydrated strata, and that is the bulk of what forms Mount Sharp. Grotzinger suggests that perhaps this later segment of the crater’s history may have been dominated by dry, wind-driven deposits, as was once imagined for the lower part explored by Curiosity.
A lingering question surrounds the original source of the water that carried sediment into the crater. For flowing water to have existed on the surface, Mars must have had a thicker atmosphere and warmer climate than has been theorized for the ancient era when Gale Crater experienced the intense geological activity. However, current models of this paleoclimate have, literally, come up dry.
At least some of the water may have been supplied to the lakes by snowfall and rain in the highlands of the Gale Crater rim. Some have made the argument that there was an ocean in the plains north of the crater, but that does not explain how the water managed to exist as a liquid for extended periods of time on the surface.
“We have tended to think of Mars as being simple,” Grotzinger mused. “We once thought of the Earth as being simple too. But the more you look into it, questions come up because you’re beginning to fathom the real complexity of what we see on Mars. This is a good time to go back to reevaluate all our assumptions. Something is missing somewhere.”
TOP IMAGE….Strata at Base of Mount Sharp A view from the “Kimberley” formation on Mars taken by NASA’s Curiosity rover. The strata in the foreground dip towards the base of Mount Sharp, indicating flow of water toward a basin that existed before the larger bulk of the mountain formed. The colors are adjusted so that rocks look approximately as they would if they were on Earth, to help geologists interpret the rocks. This “white balancing” to adjust for the lighting on Mars overly compensates for the absence of blue on Mars, making the sky appear light blue and sometimes giving dark, black rocks a blue cast. This image was taken by the Mast Camera (Mastcam) on Curiosity on the 580th Martian day, or sol, of the mission.
LOWER IMAGE….Secrets of ‘Hidden Valley’ on Mars An image taken at the “Hidden Valley” site, en-route to Mount Sharp, by NASA’s Curiosity rover. A variety of mudstone strata in the area indicate a lakebed deposit, with river- and stream-related deposits nearby. Decoding the history of how these sedimentary rocks were formed, and during what period of time, was a key component in the confirming of the role of water and sedimentation in the formation of the floor of Gale Crater and Mount Sharp.
This image was taken by the Mast Camera (Mastcam) on Curiosity on the 703rd Martian day, or sol, of the mission.
Malin Space Science Systems, San Diego, built and operates Curiosity’s Mastcam. NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, built the rover and manages the project for NASA’s Science Mission Directorate, Washington.
A SUCCESSFUL LANDING BY NASA’S CURIOSITY! What an exciting thing!
Although I’m only one measly college student sitting at home in front of a television screen, I feel blessed to be able to share this moment with these scientists and engineers, all of those individuals at JPL’s Mission Control, who were jumping out of their seats, shouting, screaming, cheering, yelling, crying, and embracing each other at the moment of touchdown. It’s a truly beautiful thing to see people unite like that. It unifies us as a country, as a world, and as a species when this amazing team of researchers achieves something larger than the focus of our own planet. It’s touching, and it’s moving to me. There was so much happiness, success, and energy in that room: so much positivity that our news often lacks. This is part of the reason why going into science excites me. It’s discoveries like these that make the immense amount of blood, sweat, and tears invested by our scientists, our engineers, our inventors, so worthwhile.
New discoveries or the possibilities of attaining them await us the more that we study something as vast and as fascinating as space. It brings people from all walks of life together. Amidst all of the violence and hatred currently present in the world, this was a happy moment in our history, and a moment to be proud of. It’s something that lifted my spirits immensely. There’s still so much to learn, and witnessing another part of our space history is somewhat exhilarating: Curiosity is definitely a large and refreshing step in the right direction.
The shades of discrimination in humanity disappear when we focus our eyes elsewhere: on something else, far out there, orbiting in the distance. And I believe there’s much more to come. Space research seems slow, and fragile, and limited as of late, but the progress with Curiosity is immense here. It’s an amazing feat by the NASA team, and I really hope that this inspires more economic support for further space research.
The universe is vast and unknown, and there’s still much to discover. It’s frustrating and nerve-racking, and you feel as if Earth is confining with all that may be out there, and discoveries that are sitting in our neighboring planets and beyond.
But perhaps, thanks to the brilliant minds that make such progress possible, some day, whether it be near or far, we as a species will be able to do much more than just wonder beside our windows.
Thank you, NASA, for making this a night to remember.