Just like Earth, Mars has vast expanses of rippled sand, but thanks to the tireless work of NASA's rover Curiosity, a new type of them has been discovered.
Said Mathieu Lapotre, one of the collaborators for the Curiosity mission, "Earth and Mars both have big sand dunes and small sand ripples, but on Mars, there's something in between that we don't have on Earth."
Such land formations, called impact ripples, generally occur as wind blows particles across the land, causing them to collide with one another and form peaks and rifts.
However, Lapotre noted, "As Curiosity was approaching the Bagnold Dunes, we started seeing that the crest lines of the...ripples are sinuous. That is not like impact ripples, but it is just like sand ripples that form under moving water on Earth."
That suggests Mars once had a much thicker atmosphere, and ripples hailing back to that time may provide insights into how it thinned over the eons.
RELATED: See photos of curiosity:
This image from Curiosity's Mastcam shows inclined beds of sandstone interpreted as the deposits of small deltas fed by rivers flowing down from the Gale Crater rim and building out into a lake where Mount Sharp is now. It was taken March 13, 2014, just north of the "Kimberley" waypoint.
This March 25, 2014, view from the Mastcam on NASA's Curiosity Mars rover looks southward at the Kimberley waypoint. In the foreground, multiple sandstone beds show systematic inclination to the south suggesting progressive build-out of delta sediments in that direction (toward Mount Sharp).
This image shows inclined beds characteristic of delta deposits where a stream entered a lake, but at a higher elevation and farther south than other delta deposits north of Mount Sharp. This suggests multiple episodes of delta growth building southward. It is from Curiosity's Mastcam.
This evenly layered rock photographed by the Mast Camera (Mastcam) on NASA's Curiosity Mars Rover on Aug. 7, 2014, shows a pattern typical of a lake-floor sedimentary deposit not far from where flowing water entered a lake.
This image shows an example of a thin-laminated, evenly stratified rock type that occurs in the "Pahrump Hills" outcrop at the base of Mount Sharp on Mars. The Mastcam on NASA's Curiosity Mars rover acquired this view on Oct. 28, 2014. This type of rock can form under a lake.
This mosaic image provided by NASA/JPL-Caltech/MSSS made from photographs taken by the Mast Camera (Mastcam) on NASA's Curiosity Mars rover looks to the west of the Kimberley waypoint on the rover's route to the base of Mount Sharp. The mountain lies to the left of the scene. Sets of sandstone beds all incline to the south, indicating progressive build-out of sediment toward Mount Sharp. These inclined beds are overlain in the background by horizontally bedded fine-grained sandstones that likely represent river deposits. (AP Photo/NASA/JPL-Caltech/MSSS)
This Aug. 15, 2014, composite image released by NASA and made by NASA's Mars Exploration Rover Opportunity, shows a view looking back toward part of the west rim of Endeavour Crater that the rover drove along, heading southward, during the summer of 2014. NASA announced Thursday, Sept. 11, 2014, that the rover has reached the base of Mount Sharp, its long-term science destination since landing two years ago. Officials say drilling could begin as early as next week at an outcrop of rocks called Pahrump Hills. (AP Photo/NASA, JPL-Caltech, Cornell University, Arizona State University)
FILE - This photo released by NASA shows a self-portrait taken by the NASA rover Curiosity in Gale Crater on Mars. (AP Photo/NASA)
In this image released by NASA on Monday, Aug. 27, 2012, a chapter of the layered geological history of Mars is laid bare in this color image from NASA's Curiosity rover showing the base of Mount Sharp, the rover's eventual science destination. The image is a portion of a larger image taken by Curiosity's 100-millimeter Mast Camera on Aug. 23, 2012. Scientists enhanced the color in one version to show the Martian scene under the lighting conditions we have on Earth, which helps in analyzing the terrain. The pointy mound in the center of the image, looming above the rover-sized rock, is about 1,000 feet (300 meters) across and 300 feet (100 meters) high. (AP Photo/NASA/JPL-Caltech/MSSS)
This photo taken Nov. 13, 2014, provided by the Jet Propulsion Laboratory and NASA and taken by the Curiosity Rover on the surface of Mars, shows the lower edge of the pale Pahrump Hills outcrop at the base of Mount Sharp includes wind-sculpted ripples of sand and dust in the middle ground. Some of the most innovative and challenging scientific research in human history is now underway in the Pahrump Hills, but not the ones 60 miles west of Las Vegas. These Pahrump Hills are down the highway another 55 million miles or so, at the base of a mountain in the bottom of a crater on the planet Mars. (AP Photo/JPL-NASA)
In this video grab Rob Manning, Flight System Chief Engineer Jet Propulsion Laboratory, Pasadena, California, right, celebrates NASA's most high-tech Mars rover Curiosity safe landing into Mars surface with a complex new landing technique at NASA's Jet Propulsion Laboratory in Pasadena, Calif., Sunday, Aug. 5, 2012. (AP Photo/Damian Dovarganes)
Kelley Clarke, left, celebrates as the first pictures appear on screen after a successful landing inside the Spaceflight Operations Facility for NASA's Mars Science Laboratory Curiosity rover at Jet Propulsion Laboratory in Pasadena, Calif., Sunday Aug. 5, 2012. The Curiosity robot is equipped with a nuclear-powered lab capable of vaporizing rocks and ingesting soil, measuring habitability, and potentially paving the way for human exploration. (AP Photo/Brian van der Brug, Pool)
In this photo released by NASA/JPL-Caltech, Mars Science Laboratory (MSL) team members react after the Curiosity rover successfully landed on Mars and as first images start coming in to the Jet Propulsion Laboratory, Sunday, Aug. 5, 2012 in Pasadena, Calif.(AP Photo/NASA/JPL-Caltech)
A United Launch Alliance Atlas V rocket carrying NASA's Mars Science Laboratory (MSL) Curiosity rover lifts off from Launch Complex 41 at Cape Canaveral Air Force Station in Cape Canaveral, Fla., Saturday, Nov. 26, 2011. The rocket will deliver a science laboratory to Mars to study potential habitable environments on the planet. (AP Photo/Terry Renna)
This image taken by NASA's Curiosity Mars rover's right-eye camera of the stereo Navcam on April 3, 2014 includes a bright spot, upper left, which might be due to the sun glinting off a rock or cosmic rays striking the camera's detector. Bright spots appear in images from the rover nearly every week. Typical explanations for them are cosmic rays hitting the light detector or sunlight glinting from rocks. (AP Photo/NASA)
In this image released on June 23, 2014, shows NASA's Curiosity Mars rover self-portrait. NASA's Curiosity Mars used the camera at the end of its arm in April and May 2014 to take dozens of component images combined into this self-portrait where the rover drilled into a sandstone target called "Windjana." NASA's Mars Curiosity rover will complete a Martian year, 687 Earth days, on June 24. (AP Photo/NASA/JPL-Caltech/MSSS)
This photo released by NASA shows a photo stitched together from nearly 900 images taken by the NASA rover Curiosity showing a section of Gale Crater near the Martian equator. Nearly a year after landing, Curiosity is finally starting the drive to a mountain in search of the chemical building blocks of life. (AP Photo/NASA)
This photo released by NASA shows a view of Mars that was stitched together by images taken by NASA's Viking Orbiter spacecraft. The space agency is planning to send a spacecraft similar to the Curiosity rover to the red planet in 2020. A NASA-appointed team released a report on Tuesday, July 9, 2013 that described the mission's science goals. (AP Photo/NASA)
This image released by NASA on Saturday Feb. 9, 2013 shows a fresh drill hole, center, made by the Curiosity rover on Friday, Feb. 8, 2013 next to an earlier test hole. Curiosity has completed its first drill into a Martian rock, a huge milestone since landing in an ancient crater in August 2012. (AP Photo/NASA)
File - An undated file image released by NASA shows a self-portrait of NASA's Mars rover Curiosity. After back-to-back computer problems, the six-wheel rover has resumed its science experiments. (AP Photo/NASA)
In this image released by NASA on Wednesday, Aug. 8, 2012, a self portrait of NASA's Curiosity rover was taken by its Navigation cameras, located on the now-upright mast. The camera snapped pictures 360-degrees around the rover. (AP Photo/NASA)