Physical features on Mars

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Slide 1

Slide 2

Check your knowledge--

Northerners have cold days in January because:

(a) the earth is farthest from the Sun in January

(b) the orbital velocity of Earth is greatest in Jan.

(c) the Sun is lower in the sky in January

(d) El Nino is always strongest in January

Slide 3

Physical Features of Mars

The Martian Surface as revealed by the Mariners, Vikings

- craters

- volcanoes

- plains

Evidence for Water on Mars

- geological

- chemical

The Martian Atmosphere

Slide 4

Fast Facts on Mars:

size = 5974 km/4200 miles

~53% Earth’s size

mass = 6.5 x 1023 kg or

0.1 Earth’s mass

density = 3900 kg/m3

(Earth’s density = 5510 kg/m3)

gravity/physics will be

different on Mars, i.e., mts.,

activity in planet’s core

Slide 5

Changes in surface coloring: thought once to be vegetation!!

Slide 6

Mariners 6 and 7

Fly by of Mars on 31 Jul 1969

- came within 2,130 miles of Mars

- pictures of ~20% surface (missed important volcanic features)

- sent back ~80 photos (Mar. 6) and ~120 photos (Mar. 7)

Mariners 6 and 7 had scientfic instruments to study Martian atmosphere:

- composition, pressure, density, and temperature

- two cameras

- infrared spectrometer

- ultraviolet spectrometer

Slide 7

Martian surface covered with craters!

- surface isn’t smooth (as historical observations thought)

- similar to Moon surface (being studied simultaneously)

- must be old: peak in impacts ~3.8 billion years ago

- difficult to see from Earth, but Mars’ thin atmosphere

- many gave up hope for seeing “water”/ “life” on Mars

Slide 8

Mariner 9 – first ORBITER spacecraft!!

Slide 9

Mariner 9 was the first spacecraft to orbit another planet

- arrived at Mars 14 November 1971

- orbited Mars for more than a year

Major dust storm on Mars when Mariner 9 arrived!

-surface was not visible for an entire month

-however, the cones of major volcanoes (new discovery) were visible

Slide 10

Craters weren’t all that was found on Mars!!