Mars and science fiction

The Moon and Mars figure prominently in science fiction, starting in the 19th century.

link to basic Mars data:


The 4th planet from the sun at 1.52 AU
–The 3rd largest rocky (terrestrial) planet in the solar system with an equatorial radius of 3402 km (3000 km smaller than Earth)
–1/3rd  Earth’s surface gravity
–Eccentric orbit (0.09 compared to 0.01 for Earth) is as important as the planet’s tilt in causing seasons
–2 small captured asteroid ‘moons’ Phobos and Deimos
–Distinctive reddish color from ‘rusted’ iron compounds
–Geologically very active in the past – home of the solar system’s largest volcano (Olympus Mons) and largest canyon (Valles Marineris)
–Possesses surface water in polar ice caps which may have flowed in ancient times
–The most clement body in the solar system (after the Earth) for supporting life as we know it

Mars through history

Visible to the naked eye and known to early astronomers
–Red color earned it the title of ‘god of war’ for the Greeks (Ares) and Romans (Mars)
–Mars' red surface color actually comes from a coating of oxidized iron-bearing rock and dust particles (like rust).

Helped Kepler derive his laws of planetary motion in 1609
–The large eccentricity could not be reconciled with circular orbits

By the late 1800s telescopes were powerful enough to observe surface features
Giovanni Schiaparelli observed the 1877 martian opposition and Percival Lowell began his observations in Flagstaff in 1893
–They claimed they saw evidence for Martian life and civilization
The ‘Canals’ and ‘Oases’ of Mars
A large greenish bluish triangular feature (Syrtis Major) thought to be plant life
–Not all astronomers could distinguish or agree on what was being seen

The "Canals":

Schiaparelli map

A fanciful "canal scape":
canal scape

from “The Decline and Fall of the Martian Empire” by Kevin Zahnle (2001) in Nature

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The great English science fiction author H. G. Wells wrote the classic "War of the Worlds",

Mars invaders
 and other authors such as Edgar Rice Burroughs and Ray Bradbury described an inhabited Mars.

In reality there are no canals and there is no vegetation -- these were just optical illusions due to the difficulties of observing Mars through the Earth's atmosphere.

View of Mars from the Mariner 4 spacecraft flyby (1965). The first close-up photographs of Mars were from spacecraft, and they indicated a bleak, cratered, lunar-like landscape.
Mariner 4 closeup

Hope of ancient civilizations on Mars were dashed

View of Mars from the Hubble Space Telescope, showing the north polar cap and high clouds over the Tharsis volcanoes:
HST Mars

Before we had such data, Mars remained largely a mystery until the robotic exploration of the 1960s and 1970s.

Mars Exploration

Mars has been a hard target to explore.  Here is a scorecard:

Some successful (and unsuccessful) landing sites:

Mars landing sites

The latest Mars mission is the Curiosity rover, landed in 94-km diameter Gale Crater last summer:
Gale Crater

Curiosity's landing zone has been named Bradbury Landing, in honor of Ray Bradbury:
Bradbury Landing

Mars' greatest similarity to Earth: polar caps and seasons

Mars has subsurface water at high latitudes and ice caps at both poles.  Like the Earth's ice caps, Mars' ice caps change with the seasons:
Mars north pole changes

The ice caps are composed of water ice overlain at times by "dry ice" (carbon dioxide ice)
–Northern cap is much larger than the southern cap
–Both caps are dissected by spiral troughs
Not well understood what causes the spiral pattern
Thought to be some kind of interplay between sun and sublimation of ice
Troughs are composed of layers
Mars north


Each cap has a permanent and seasonal component
–Permanent cap is water ice
–Seasonal cap is frozen carbon dioxide ("dry ice")

There is a great deal of ice off the cap, especially in the Northern Lowlands
–detected by Mars Odyssey

This ice is frozen throughout the martian year leading to a condition in the soil known as permafrost
–Leads to the formation of Ice Wedge Polygons:
Contracting ice cracks
Cracks infill with more water (or dust)
Crack location from the previous year is a weak spot and re-cracks the next year
The process repeats

Here is a view of the polygonal terrain from orbit:
martian polygons

And here is a closeup view from the UA Phoenix Lander, which is situated in the martian arctic in just such an ice-polygon region:

ice polygon

An image of the underside of the Phoenix lander, where the landing thrusters have blown aside a thin surface layer of dust to reveal solid ice.

Holy cow!

Mars is both Earthlike and Moonlike