Geology on Mars and Comparing Rocky Planets

Vocabulary flashcards detailing the four spheres (atmosphere, geosphere, biosphere, hydrosphere) across the rocky planets: Venus, Mercury, Mars, and Earth.

Atmosphere of Venus

The thickest atmosphere among the four rocky planets, made mostly of carbon dioxide with swirling clouds that trap heat and keep surface temperatures very hot day and night.

Geosphere of Venus

The rocky surface of Venus, featuring hardened lava, craters, and volcanoes that may still be active.

Biosphere of Venus

A non-existent sphere on Venus, as no living things could survive on its harsh, hot, and dry surface.

Hydrosphere of Venus

Venus currently has no hydrosphere, but atmospheric evidence indicates it had liquid water billions of years ago before high temperatures turned it into gas.

Atmosphere of Mercury

A minimal atmosphere where tiny amounts of oxygen and other gases released from the surface quickly float away into space, causing extreme heat on the sunlit side and extreme cold on the shaded side.

Geosphere of Mercury

The rocky surface of Mercury, covered with thousands of craters and resembling Earth's Moon, with past lava flows billions of years ago but no active volcanoes.

Biosphere of Mercury

Mercury has no known biosphere, with no evidence that anything lives or has ever lived on the planet.

Hydrosphere of Mercury

Mercury lacks liquid water, but scientists have found evidence of frozen water hidden deep inside dark craters at its poles.

Atmosphere of Mars

A thin atmosphere made of carbon dioxide and nitrogen that gets very cold, featuring winds that blow red dust across the surface to give the air a pink color.

Geosphere of Mars

The rocky surface of Mars, characterized by craters, volcanic vents, and giant volcanic landforms including the largest volcano in the solar system.

Biosphere of Mars

Mars has no proven biosphere, but scientists search for evidence to determine if it was habitable in its warmer past.

Hydrosphere of Mars

Mars has no current surface liquid water, though it possesses frozen water ice at its poles and rock formations that evidence past liquid water.

Atmosphere of Earth

A mixture of gases primarily composed of nitrogen and oxygen, with small amounts of carbon dioxide, keeping the planet's surface warm but not too hot.

Geosphere of Earth

The rocky structure of Earth from surface soil down to its iron core, shaped by earthquakes, volcanic eruptions, flowing rivers, and ocean waves.

Biosphere of Earth

The system of living things unique to Earth that shapes the planet, such as trees generating oxygen and preventing hillside erosion.

Hydrosphere of Earth

Earth's water network of oceans, lakes, rivers, and ice caps, making Earth the only known planet with liquid water bodies on its surface.

Craters

Round holes on a planet's rocky surface left by space rocks impacting the surface.