Annie Aquino Quiz

Annie Aquino
3/1/13
Astronomy
Chapter7

Why is Earth geologically active?

-Earth and the other terrestrial worlds were once hot enough inside for their interiors to
melt, allowing material to settle into layers of differing density
-larger planets retain internal heat much longer than the smaller ones, and this
heat drives geological activity.
-Earth's magnetic field is generated by the motions of molten metal in its liquid outer
core.

What processes shape Earth's surface?

-Virtually all geological features originate from impact cratering, volcanism, tectonics
and/or erosion.
-Like all terrestrial worlds, Earth was bombarded by impacts when it was young, but
most ancient craters have been erased by other geological processes.
-Earth's atmosphere and oceans were made from gases released from the interior by
volcanic outgassing
-Tectonics and volcanism generally occur together because both require internal heat
and therefore depend on a planets size

How does Earth's atmosphere affect the planet?

-ozone absorbs the sun dangerous ultraviolet radiation, while the x rays are absorbed
by atoms and molecules higher up in the earths atmosphere

-the greenhouse effect keeps Earths surface much warmer than it would be otherwise,
allowing water to stay liquid over most of the surface

Was there ever geological activity on the Moon or Mercury?

-The moons dark , smooth maria were made by floods of molten lava billions of years
ago when the moon interior was heated by radioactive decay.
-mars has extremely active volcanism in the past and its surface is dotted with
numerous large volcanoes

-dried up riverbeds and other signs of erosions show that water flowed on Mars in the
distant past
-Gullies on crater walls suggest that water might still occasionally flow on Mars today.

why did mars change?

-early in it's history, mars probably had a dense atmosphere from volcanic outgassing
with a stronger greenhouse effect than it has today

-Mara underwent permanent climate change about 3 billion years ago when it lost much
of its atmospheric carbon dioxide and water to space

Is Venus geologically active?

-venus shows features of volcanism and tectonics just as we expect for a planet of
similar size of earth
-Venus's lack of earth like plate tectonics poses a scientific mystery but may arise
because venus has a thicker and stronger lithosphere than earth

Why is Venus so hot?

- Venus's thick carbon dioxide atmosphere creates the extremely strong green house
effect that makes venus so hot.

-Venus retains carbon dioxide in its atmosphere because it lacks oceans o dissolve the
carbon dioxide and lock it away and rock.

-Venus is too close to the sun to have liquid water oceans and without the oceans to
dissolve the carbon dioxide it is doomed to its runway green house effect.

What unique features of Earth are important for life?

-surface liquid water, atmospheric oxygen, plate tectonics, climate stability

How is human activity changing the planet?

-human activity is rapidly increasing the atmospheric concentrations of green house
gases, causing the global average temperature to rise

what makes a planet habitable?

- the earth is habitable because it is large enough to remain geologically active and
located at a distance from the sun where oceans were able to form