The Solar System:
Water (and life?) on Mars
Is there liquid water on Mars?
Evidence of current frozen water ice
Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment (HiRISE) camera acquired this image of the Phoenix Mars Lander hanging from its parachute as it descended to the Martian surface in 2008.Credit (image and some text): NASA/JPL-Caltech/University of Arizona [link]
This artist's concept depicts NASA's Phoenix Mars Lander a moment before its 2008 touchdown on the arctic plains of Mars, in the north polar region. Pulsed rocket engines controlled the spacecraft's speed during the final seconds of descent. Phoenix's mission was to search for water.Credit (image and some text): NASA/JPL-Calech/University of Arizona [link]
The Robotic Arm Camera on NASA's Phoenix Mars Lander captured this image underneath the lander on the fifth Martian day, or sol, of the mission. Descent thrusters on the bottom of the lander are visible at the top of the image.Credit (image and some text): NASA/JPL-Caltech/University of Arizona/Max Planck Institute [link]
These color images were acquired by NASA's Phoenix Mars Lander's Surface Stereo Imager on the 21st and 25th days of the mission, or Sols 20 and 24 (15 and 19 June 2008).
This 12-meter-wide (39-foot-wide) crater in mid-latitude northern Mars was created by an impact that occurred between 3 July 2004 and 28 June 2008, as bracketed by before-and-after images not shown here. The images shown here were obtained by the High Resolution Imaging Science Experiment camera on NASA's Mars Reconnaissance Orbiter on 19 November 2008 (left) and 8 January 2009. The impact that dug the crater excavated water ice from below the surface. It is the bright material visible in this pair of images.
Evidence of vanished ancient liquid water on the surface of Mars
The same image of Kasei Valles colored to highlight topographic changes in height, from red/yellow colors at high altitude to blue/purple colors at low altitudes.Credit: Institute of Geological Sciences at Freie Universität Berlin in cooperation with the DLR Institute of Planetary Research, Berlin [link]
Ancient river channels emptying into a crater (former lake)?
A Mars Odyssey spacecraft image of a large (14 km x 19 km) area of the Martian surface near Holden Crater, a 64 km wide crater whose northern edge is visible at the bottom of this image. A number of ancient flow channels (i.e., "river beds") are visible, with several leading into the smaller crater "Holden NE" (at upper right). The inset square outlined in white is shown in detail in the next figure.Credit (image and some text): NASA/JPL/Malin Space Science Systems [link]
Detailed look at the floor of "Holden NE" Crater from the Mars Odyssey spacecraft image shown in the previous figure. Two ancient flow channels (rivers?) empty into the crater (a lake?) from the lower left corner and middle left side of this image. A "fossil" sediment distribution fan (a river delta?) emanating from these two channels spreads across the floor of the crater. The originally loose sediment in the channels of the fan has been turned to rock and then eroded over time to present the features seen today. The channels through which sediment was transported are no longer present; instead, only their floors have remained, and these have been elevated by erosion of the surrounding material so that former channels now stand as ridges. The floors of former channels became inverted because they were more resistant to the forces of erosion - either they were more strongly cemented than the surrounding materials, or they have more coarse grains (which are harder to remove), or both.Credit (image and some text): NASA/JPL/Malin Space Science Systems [link]
Selenga River delta on the southeast shore of Lake Baikal, Russia. The fossil sediment distribution fan in "Holden NE" Crater on Mars is very similar in appearance to the same type of structure in an active river system on Earth.Credit: "Earth As Art" satellite image courtesy of the USGS National Center for Earth Resources Observation and Science (EROS) and the National Aeronautics and Space Administration (NASA) Landsat Project Science Office [link]
Sedimentary rock in ancient (now dry!) lakebed. This evenly layered rock photographed by the Mast Camera (Mastcam) on NASA's Curiosity Mars Rover shows a pattern typical of a lake-floor sedimentary deposit not far from where flowing water entered a lake. These rocks are interpreted to record sedimentation in a lake, as part of or in front of a delta, where plumes of river sediment settled out of the water column and onto the lake floor.This view spans about 1.5 meters (5 feet) across in the foreground. The color has been approximately white-balanced to resemble how the scene would appear under daytime lighting conditions on Earth.Credit (image and some text): NASA/JPL-Caltech/MSSS [link]
Evidence of current liquid (subsurface and surface) water
ESA’s Mars Express used radar signals bounced through underground layers of ice to find evidence of a pond of liquid water buried below the south polar cap of Mars.Credit (image and some text): Context map = NASA/Viking; THEMIS background = NASA/JPL-Caltech/Arizona State University; MARSIS data = ESA/NASA/JPL/ASI/Univ. Rome; R. Orosei, et al. (2018) [link]
This time-lapse movie was assembled from images of the surface of Mars (Horowitz Crater in Terra Cimmeria) obtained by an orbiting satellite (MRO/HiRISE), and shows features called “recurring slope linae” – which basically just means “lines on a hill that keep reappearing”. These have been interpreted as surface water flowing downhill.
Possibilities for life on Mars?
Just to be abundantly clear: this image is only meant to be funny! Bigfoot does not live on Mars! It's just a rock formation.Credit: assembled by D. W. Hoard (2018) from various internet sources that are extremely reliable (also a joke! really wish I didn't feel like I have to keep pointing that out!).
The Mars Orbiter Laser Altimeter (MOLA) aboard the Mars Global Surveyor produced the first global map of the topography of Mars. The Hellas Basin (large purple feature at about 60 degrees longitude in the southern hemisphere) is a giant impact basin like the maria on the Moon. It is 2300 km across and 9 km deep.Credit (image and some text): NASA/JPL/GSFC [link]
It is possible that the giant impact in Mars' past that “repaved” the northern hemisphere (see topographic map in previous figure) also disrupted the internal dynamo mechanism for generating Mars’ magnetic field and, therefore, led to the loss of most of Mars' atmosphere.Credit: NASA [link]; also see Connerney, J. E. P. et al., 2005, Proceedings of the National Academy of Science (USA), 102, 14970 - "Tectonic implications of Mars crustal magnetism" [link]