Geology and Habitability of Terrestrial Planets

A set of flashcards summarizing key concepts regarding the geology, atmosphere, and habitability of terrestrial planets, particularly Earth, as discussed in the lecture.

What are the two major types of planets based on their formation conditions?

Inner planets (terrestrial) and outer planets (gas giants).

What geological processes shape the Earth's surface?

Impact cratering, volcanism, tectonics, and erosion.

What is the Frost Line in the context of planet formation?

The location in the solar nebula beyond which it is cold enough for hydrogen compounds to condense into ices.

How did Earth's water likely originate?

Water may have come via planetesimals during Earth's formation or from later bombardment by icy planetesimals.

What is accretion in the context of terrestrial planet formation?

The process by which small particles of rock and metal collide and stick together, eventually forming larger bodies.

What is the greenhouse effect?

A natural process where certain gases trap heat in Earth's atmosphere, contributing to the warmth of the planet.

How do smaller planets compare to larger ones in terms of geological activity?

Smaller planets cool off faster and tend to be geologically 'dead' sooner than larger planets.

What unique features of Earth are critical for sustaining life?

Surface liquid water, atmospheric oxygen, plate tectonics, and climate stability.

What is the role of plate tectonics in Earth's climate?

Plate tectonics helps regulate climate stability and supports the carbon dioxide cycle.

Why is Venus much hotter than Earth despite being similar in size?

Venus has a thick carbon dioxide atmosphere leading to a runaway greenhouse effect that raises surface temperatures.

Why do craters on Earth differ from those on the Moon?

Most cratering on Earth happened soon after the solar system formed, while the Moon has preserved its ancient craters.

What evidence suggests old water existed on Mars?

Features like dry riverbeds, eroded craters, and sedimentary rocks indicating past water flow.

What impact does Earth's atmosphere have on its surface?

It protects from radiation, supports weathering processes, and regulates temperature through the greenhouse effect.

What is the main distinction between Earth's atmosphere and that of Mars?

Mars has a thin CO2 atmosphere, which cannot support a strong greenhouse effect necessary for liquid water.

How do seasonal changes on Mars differ from those on Earth?

Mars experiences more extreme seasonal variations, particularly in its southern hemisphere due to its elliptical orbit.