1/ Astronomers estimate that the plains of Venus are only about 500 to 600 million years old.How do they estimate dates like this?
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1/ Astronomers estimate that the plains of Venus are only about 500 to 600 million years old.  How do they

estimate dates like this?

by counting the craters visible on the surface and comparing crater counts to other worlds 

by looking for little brass plates that give the founding date and the name of the governor at the time

by looking at the radioactive rock samples that have been returned to Earth from Venus

by seeing how much the continental plates on which the Venus plains are floating have spread apart

by noting that all the plains on all the terrestrial planets have the same age

2/ Why does Mars have an overall reddish color when we see its surface from afar?

the giant volcanoes on Mars are constantly spewing out reddish lava

Mars is completely cloudy, and its clouds are made of red materials

This is an optical illusion caused by the Earth's atmosphere scattering the colors of light differently

The martians are constantly at war, and spilling a lot of red blood

The material of Mars' surface contains a lot of iron oxide, the same chemistry that makes rusting metals look reddish

3/ The process by which Venus became so much hotter than the Earth is called:

the runaway greenhouse effect 

tectonic displacement

the twisted sister effect


ozone depletion

4/ Which of the following is evidence for volcanic activity on Venus?

the existence of large volcanic mountains such as Sif Mons

the discovery of thousands of small volcanic cones of the surface of Venus

all of these 

the pancake domes of Venus

the fact that the lava plains are only 500 million or so years old

5/ The observation that began the 19th and early 20th century fascination with Mars as a place for life was:

the landing of Martian spacecraft in New Jersey in 1938

Schiaparelli's seeing what seemed to him to be long straight features on the red planet 

Percival Lowell's discovery of an entire network of artificial canals built by martians

the discovery of the Martian moons

the images sent back by the Viking spacecraft mission

6/ Which of the following is NOT one of the key reasons that so many spacecraft from Earth have visited Venus and Mars?

they resemble the Earth in a number of significant ways

both have tantalized us when seen through a telescope -- one because it is perpetually covered by clouds, the other because it shows seasonal changes

their atmospheres are very similar to the Earth in terms of their chemical make-up

they are the two planets closest to the Earth

they each have a solid surface on which we can trace their geological history

7/ The largest volcano on Mars is called: 

Mariner Valley     

Mount Maxwell

Olympus Mons (Mt. Olympus)     


the Red Spot     

8/ Mars appears to have long branching channels that have the appearance of being formed by a flowing liquid.  Yet we know that liquids would not stay liquid in the very thin atmosphere we have on the Martian surface?  So how can we explain the channels?

the channels are artificial, made by a race of Martians that died out

they were made by wind-blown dust during the great Martian dust storms

they are made by plate tectonics; by plates in the crust separating

they were formed by volcanic lava from Olympus Mons

Mars had a thicker atmosphere long ago when the channels formed  

9/ Astronomers believe that Mars formed with a much thicker atmosphere than it has today.  Where did this atmosphere go?

it was absorbed by the rocks on Mars, which are much more absorbent than on Earth

it was drawn into the crust and mantle of Mars through the enormous cracks of the Mariner Valley canyon system

it escaped into space (and some later froze out as Mars got cold)

no one has any good theories about this; it is an unsolved mystery

it is trapped in bubbles inside the rocks on the martian surface

10/ The canals that late 19th and early 20th observers thought they saw on Mars turned out to be:

enormous cracks caused by extensive plate tectonics on Mars

huge chains of thousands of large volcanoes

built by the same race of ancient martian engineers who constructed the "face on Mars"

optical illusions 

very narrow oceans of water

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