What Mars Actually Looks Like!

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Article written by Jim Secosky. Jim is a retired science teacher who has used the Hubble Space Telescope, the Mars Global Surveyor, and HiRISE.


Almost all of the sites that we have landed on Mars with spacecraft have been to the most drab and boring places on the planet. This was done to ensure a safe landing. This article will display many of the more exciting landscapes using HiRISE images. HiRISE images can show detail down to the size of a small kitchen table. With HiRISE we frequently even see spacecraft that have landed on the surface. Many of the scenes shown here are about one would see at the height of a helicopter. Most of the HiRISE images here were obtained through the HiWish program, a program where anyone could suggest places to be imaged with HiRISE. To obtain the images, I studied wide angle CTX images to find sites that could contain interesting features. I was lucky that many of my suggestions were photographed, and I was able to gather them together for this article.

Viking 1

Viking 1 was the first successful spacecraft to land on Mars. It landed on July 20, 1976 at 22.27 N and 47.95 W (312.05 E). July 20th was also the date when we first landed on the moon in 1969.

Rocks and dunes, as seen from Viking 1 Holes were dug by the digging tool. Part of the meteorology boom is visible.

Viking 2

Viking 2 landed on September 3, 1976 at 47.64 N and 275.71 W (84.29 E).

View from Viking 2

Mars Pathfinder

The Mars Pathfinder landed on July 4, 1997 at 19 degrees 7’ 48” in Ares Vallis.

Wide view from Mars pathfinder, showing Sojourner Rover

Spirit Rover

The Spirit Rover landed on January 4, 2004 at 14.5684 S and 175.472636 E (184.527364 W).

Opportunity Rover

The Opportunity Rover landed on January 25, 2004 at 1.9462 S and 354.4734 E (5.5268 W).

Phoenix

Phoenix landed in the far North of Mars on May 25, 2008 at 68.22 N and 125.7 W (234.3 E) in Vastitas Borealis.

Wide view from Phoenix lander Solar panels are visible.

Curiosity Rover

The Curiosity Rover landed on August 6, 2012 at Gale Crater in Aeolis Palus at 4.5895 S and 137.4417 E (222.5583 W). By this time scientists were able to be more precise with their landings, so Curiosity has been able to get views of Mars that are pretty exciting.

Early view from Curiosity Mount Sharp is in the distance. The shadow of Rover is visible. Mount Sharp at a height of about 3.4 miles is taller than Mt. Whitney in California.

What follows are a few pictures of the many different scenes that we have studied with powerful cameras on board the Mars Reconnaissance Orbiter that has been going around Mars for over 10 years.

Dunes

The Martian surface displays many beautiful dark dunes. For many years, scientists thought dark dunes were composed of the grains of sand from the volcanic rock basalt; this was confirmed by rovers on the surface.[1] The dunes are covered by a seasonal carbon dioxide frost that forms in early autumn and remains until late spring.

Layers

Many places on Mars show rocks arranged in layers. Volcanoes, wind, or water can produce layers.[3] Layers can be hardened by the action of groundwater.

Layers and fault in Firsoff Crater

Layers and fault in Firsoff Crater in Oxia Palus quadrangle, as seen by HiRISE under HiWish program

Layers in Crommelin Crater


Layers in Danielson Crater in Oxia Palus quadrangle

Glaciers

There are large areas on Mars that contain what is thought to be ice moving under a cover of debris. A few meters of debris can preserve ice for long periods of time.[4]

Several types of landforms have been identified as probably dirt and rock debris covering huge deposits of ice.[5] [6] [7] [8] Concentric crater fill (CCF) contains dozens to hundreds of concentric ridges that are caused by the movements of sometimes hundreds of meter thick accumulations of ice in craters.[9] [10] Lineated valley fill (LVF)are lines of ridges in valleys.[11] [12] [13] These lines may have developed as other glaciers moved down valleys. Some of these glaciers seem to come from material sitting around mesas and buttes.[14] Lobate debris aprons (LDA) is the name given to these glaciers. All of these features that are believed to contain large amounts of ice are found in the mid-latitudes in both the Northern and Southern hemispheres.[15] [16] [17]

Mesa with Lobate Debris Aprons (LDA) Orbiting radars have detected ice in LDA’s under a thin cover of debris.
Labeled view of Lineated Valley Flow and glacier


Gullies

Martian gullies are networks of narrow channels and their associated downslope deposits, found on steep slopes. A high concentration occurs near 40 degrees north and south of the equator. Usually, each gully has an alcove at its head, a fan-shaped apron at its base, and a channel linking the two.[18] They are believed to be relatively young because they have few, if any craters. They were believed to be caused by recent running water, but with more observations it was shown that pieces of dry ice moving down slopes could cause them.

Channels

There are thousands of channels that were probably caused by running water in the past on Mars. Some are large; some are tiny.[20] [21] [22] [23] [24]

Troughs

The great weight of several huge volcanoes on Mars has stretched the crust and made it break into cracks called, “troughs” or “fossae.” Some of them show evidence that lava and/or water have come out of them in the past. They can be very long.[25] [26] [27]

Craters

Most of the surface of Mars is over a billion years old. Because Mars has not had active plate tectonics for a very long time (if it ever had active plate tectonics), impact craters stay for a long time. So, impact craters are a major surface feature. There is a rich variety of craters on the planet.[28] [29]

Scalloped Terrain

Scalloped topography is common in the mid-latitudes of Mars, between 45° and 60° north and south. It is especially prominent in the region of Utopia Planitia.[31] [32] Such topography consists of shallow, rimless depressions with scalloped edges, commonly referred to as "scalloped depressions" or simply "scallops". Scalloped depressions can be isolated or clustered and sometimes seem to coalesce. The usual scalloped depression displays a gentle equator-facing slope and a steeper pole-facing scarp.[33] Scalloped topography may be of great importance for future colonization of Mars because it may point to deposits of pure ice.[34] [35]

Scalloped terrain in Casius quadrangle

Brain Terrain

Brain terrain is a region of maze-like ridges 3–5 meters high. A person could wander between these ridges like a rat in a maze. Some ridges may consist of an ice core, so they may be sources of water for future colonists.[36]

Ribbed terrain

Ribbed terrain forms as ice leaves the ground along cracks in a process called " sublimation." Much of the ground is ice so that when the ice disappears the ground collapses.[37]


Wide view of ribbed terrain in Ismenius Lacus quadrangle
Ribbed terrain in Ismenius Lacus quadrangle

Linear Ridge Networks

This terrain appears over much of the planet. It consists of groups of narrow ridges that often meet at close to right angles. We are not sure of how it originated. It may have been caused by fluids moving into cracks that were created by impacts. The fluids then became hard and erosion resistant.[38] [39] [40] [41] [42] [43] [44]

Yardangs

Yardangs form from fine-grained material. They are shaped by the wind and show the direction of the prevailing winds. Much of this fine-grained material probably has its origin in the many large volcanoes on the planet. Yardangs are especially common in what's called the "Medusae Fossae Formation." This formation is found in the Amazonis quadrangle and near the equator.[45] Because they exhibit very few impact craters they are believed to be relatively young.[46]

Dust Devil Tracks

Dust devil tracks can be very beautiful. They are made by giant dust devils removing bright colored dust from the Martian surface; consequently exposing a dark layer. Dust devils on Mars have been photographed both from the ground and from orbit. They have even blown dust off the solar panels of two Rovers on Mars, thereby greatly extending their useful lifetime.[47] The pattern of the tracks has been shown to change every few months.[48]

Dust devils photographed by Mars Rover Spirit

Dark Slope Streaks

Dark slope streaks are avalanche-like features common on dust-covered slopes, especially in the equatorial regions .[49] They form in relatively steep terrain, such as along cliffs and crater walls.[50] The darkest streaks are only about 10% darker than their surroundings. The streaks seem much darker because of contrast enhancement in the image processing.[51]

Lava

Large areas of Mars are covered with lava flows.[52] [53] [54] [55]

Mud Volcanoes

Mud volcanoes are very common in the Mare Acidalium quadrangle. Because they bring up mud from underground, they may hold sources of evidence of life. Being underground the mud was protected from radiation on the surface. Methane has been detected on Mars; methane may be produced by certain bacteria. Some scientists speculate that methane may come from mud volcanoes.[56]

Mud volcanoes in Mare Acidalium quadrangle

Honeycomb Terrain

Honeycomb terrain is found on parts of the floor of Hellas Planitia. It may be due to rising bodies of ice followed by erosion.[57] [58] [59]

Honeycomb terrain in Hellas quadrangle

Fractured Surface and Blocks

In many places on Mars bedrock breaks up into large blocks. Sometimes the blocks form what look like perfect cubes. Although one may think these shapes had to be made by intelligent aliens, this is a natural process. The salt you put on your food also breaks up into cubes. Check your salt out with a magnifying glass.

Rock breaking up into cube-shaped blocks

Fractured Ground

Some places on Mars break up with large fractures that create a terrain with mesas and valleys. Some of these can be quite pretty.

Dipping layers

Groups of layers that are tilted are common in some areas of Mars. They represent material that once covered a wide area.[60] [61] The layers may be related to changes in the climate in the past. They may have been shaped by the wind.

Boulders

Much of the surface of Mars is covered with hard, basalt volcanic rock. When the rock breaks down it often forms large boulders the size of houses.

Hollows

Some places on Mars have surfaces that are covered with hollows. Sometimes they form large holes, sometimes curved canyons. They can be pretty and would be fun to explore on foot in the future. This terrain may have developed from what has been called ribbed terrain. Either way, these scenes were caused as ice left the ground.

Mesas

Many, large areas of Mars have eroded such that there are many mesas. Some show layers. Mesas show how the kind of material that covered a wide area. Mesas are what are left after the ground is mostly eroded.

Landslides

Mars shows various mass movements like landslides. There are many steep slopes for material to move down, especially in craters and canyons.

Latitude Dependent Mantle

Latitude Dependent Mantle is very common in certain latitudes.[62] It often appears as a smooth covering. A certain percentage of it consists of ice. It may be a major source of water for future colonists because it has a widespread distribution. Sometimes mantle displays layers because it was deposited at different times.


Exhumed craters

Exhumed craters seem to be in the process of being uncovered.[63] The surface of Mars is very old. Places have been covered, uncovered, and covered again by sediments. The pictures below show a crater that is being exposed by erosion. When a crater forms, it will destroy what's under it. In the example below, only part of the crater is visible. Had the crater been created after the layered feature, it would have removed part of the feature and we would see the entire crater.

Swiss Cheese Terrain

Parts of Mare Australe show pits that make the surface look like Swiss cheese.[64] [65] [66] [67] These pits are in a 1-10 meter thick layer of dry ice that lies on a much larger water ice cap. These circular pits have steep walls that work to focus sunlight, thereby increasing erosion. For a pit to develop, a steep wall of about 10 cm and a length of over 5 meters in necessary.[68]

Swiss Cheese Terrain near South Pole, as seen by HiRISE

Ice Cap Layers

The northern ice cap of Mars displays many layers of ice that accumulated when the climate changed. These are visible when there is a canyon in the ice.

Spiders

As the temperature goes up in the spring, pressurized carbon dioxide gas and dark dust are released from under slabs of ice. This results in the appearance of dark plumes that are often blown in one direction by local winds. This dust darkens channels under the ice and forms dark shapes that resemble spiders.[69] [70] [71] [72]

Spiders and plumes, as seen by HiRISE under HiWish program

Polygonal Patterned Ground

Many surfaces on Mars display “polygonal patterned ground.” The polygons can be of different shapes and sizes. They are believed to be caused by ice in the ground. These may still be another marker for underground ice that could be used by future colonists. Before we land crews on Mars, we may very well have detailed maps for where the colonists can obtain water.

Notes about pictures

Most pictures from spacecraft have some sort of enhancement. For many views of Mars there is not much contrast, so the contrast is enhanced in a process known as stretching. In that process the darkest parts are set to black while the lightest parts are set to be white. The colors for HiRISE images are different than the human eye would see. HiRISE only sees in only 3 colors and sometimes infrared is used rather than red. Displaying colors in this way allows us to better identify rocks and minerals. HiRISE images are about 5 km wide with a 1 km wide band in the center that is in color.[73]

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See Also

External links