Chapter 10: Mars

2nd

Mars is the planet with the ____ most eccentric orbit (after Mercury).

making seasons vary more

The eccentricity of Mars’ orbit contributes to ____________ on Mars.

0.93

What is the eccentricity of Mars’ orbit?

The distance between Mars and Sun

What is a factor for the reasons for seasons on Mars?

opposition

Mars appears biggest and brightest at ______, when Earth is between Mars and the Sun. So, it is best viewed in this position.

Mars is smaller (less surface area to reflect light), farther away from the Sun, and is less reflective (clouds on Venus are more reflective)

What are three reasons that Mars does not appear as bright as Venus?

2; Phobos and Diemos

How many moons does Mars have and what are their names?

Rotation and axial tilt (24.6 hours; 24°)

Which two properties of Mars are similar to those properties for Earth?

Low altitudes in the northern hemisphere (volcanic planes with few craters) and high altitudes in the southern hemisphere (highlands 5 km higher and heavily cratered)

What are some major differences between the northern and southern hemispheres on Mars?

3 billion years; 4 billion years

How old are the northern and southern hemispheres?

It was paved more recently from molten material.

What may have caused low altitudes in the northern hemisphere?

Vast volcanic plateau; less heavily cratered, youngest (2-3 billion years old), 10 km higher than surface, only continent-sized feature.

What is the Tharsis Bulge and is it relatively older or younger than other features on Mars?

Impact crater, deepest feature on Mars (9 km below sea level); older feature (4 billion years old)

What is the Hellas Basin and is it relatively older or younger than other features on Mars?

Depression/lowland near North Pole; might have been largest impact feature in the entire solar system (2000 km), responsible for hemisphere differences, made everything molten and smooth in northern hemisphere.

What is the Borealis Basin?

Similar to a canyon, but not actually a canyon (no WATER erosion); formed similar to Tharsis Bulge (erosion), larger than Grand Canyon.

What is the Valles Marineris?

Olympus Mons (size of Texas; 25 km above surrounding plains); a shield volcano

What is the name of the largest volcano in the solar system and what type of volcano is it?

Form when lava wells up at a “hot spot” in the crust and are built up over time by continued eruptions; not connected to plate tectonics.

What is a shield volcano?

Its’ low surface gravity (less mass)

Why is Mars able to “grow” very tall volcanoes?

No evidence

Are the volcanos on Mars still active?

Its’ atmosphere is very erosive; small debris passes through its’ thin atmosphere, but it erodes

Why are there so few small impact craters on the surface of Mars?

Motion that appears to be backward motion, but is not.

What is retrograde motion?

Runoff channels in southern highlands allowed circulation of water all over the planet.

What are some examples of evidence for past running water on Mars?

A layer of permafrost; fluidized eject craters that suggests there was an impact on an icy surface turned into liquid water and caused a “splash”. Some type of sliding of melting material (ice caps).

What do scientists believe exists just a few meters below the Martian surface? What evidence supports this claim?

Iron rich rocks react with free oxygen to create iron oxide. Like rust.

Why is Mars red?

95.3% carbon dioxide, 2.7% nitrogen, 1.6% argon and trace amounts of oxygen and water vapor.

What is most of the Martian atmosphere made of?

Mars has a thin atmosphere, which cannot retain heat.

What is the reason for the somewhat dramatic temperature changes observed on Mars between night and day?

Reverse runaway greenhouse effect; carbon dioxide was only absorbed by its surface into the liquid water that use to be on Mars, but with no way to put it back into the atmosphere, causing a drop in temperature.

Venus and Mars have similar atmospheric compositions, but Mars; atmosphere is 10,000 times thinner. Why?

No magnetic field; rotates fast enough, but has a smaller iron core with a liquid iron outer core making contact with a thick layer of molten rock.

Does Mars have a global magnetic field?

No plate tectonics

Does Mars have plate tectonics?

Lower orbit, larger size; orbital period of 7 hr 30 min (less than a Martian day). Rises in the west and sets in the east (appears to move backwards).

What are characteristics of Phobos and its orbit?

High orbit, smaller size; orbit period of 30 hr 18 min (orbital period that exceeds the rotational period of Mars). Rises in the east and sets in the west (appears to move forward).

What are the characteristics of Deimos and its orbit?

Yes; counterclockwise orbits around Mars

Are the moons of Mars in synchronous orbit?

It takes the same amount of time to rotate as it does to complete one orbit. The same face of these moons always face Mars.

What is a synchronous orbit?

Density of both of these moons are about 2,000 kg/m³ which tells us it’s unlikely that either of the moons formed with Mars.

Did the moons of Mars form with Mars? How do we know?

Full, so you can’t see topographical features like craters or mountains; also brighter than some stars

When Mars is at its brightest, it is ______.

change with the season

We can see ice caps and dark spots from Earth, and they appear to _________.

dusty winds (strong like a hurricane)

The surface of Mars contains craters and eroded areas from ________.

Volcanos, deep canyons, and vast dune fields.

Mars’ surface contains what features?

Earlier conditions were warmer with liquid water, then it froze due to its thin atmosphere causing a permafrost layer to form below the surface, then impacts and volcanic activity led to flash floods around the surface permitting water flow.

What is the possible timeline for Mars?

currently existing liquid water lake under ice in the southern polar cap

In 2018, researchers found evidence of _______.

Utopia

Viking 2 landed in the region called ______.

Rich in iron (reacts with free oxygen to create iron oxide)

Viking 1 and Viking 2 found that surface rocks are _________.