Lecture 3 Flashcards
What is the habitable zone in a planetary system?
It is the range of orbital distances where temperatures on the surface of an Earth-like planet would allow liquid water to exist
Which parts of the Earth’s interior and surface are solid, and which ones are liquid (molten)?
Inner core=solid, outer core=liquid, mantel=solid, crust=solid
How did Earth form?
Over 50 million years ago via planetesimal accretion
Half-life for the decay chain
4.47 billion years
What do plate tectonics do?
Continuously renew the surface of the Earth
How do plate tectonics work?
Subduction occurs at ocean trenches, where dense seafloor crust pushes under less dense continental crust, thereby returning seafloor crust to the mantle
Why is Earth’s mantle in constant convective motion?
Because our planet releases its internal heat in this manner
Which one is the primary component of Earth’s atmosphere (i.e. the most abundant gas in the air that you breath)?
Nitrogen (78%)
Why is the Earth’s magnetic field beneficial for its habitability?
because it protects the Earth’s atmosphere from harmful solar wind particles
Origin of Earth’s atmosphere
Asteroids brought in ice, heated to form water vapor, water vapor grouped together and fell back to earth as condensation forming the ocean, swept carbon dioxide into rocks leaving nitrogen in the atmosphere
How does the atmospheric Greenhouse Effect really work?
Atmospheric carbon dioxide absorbs and later re-emits the infrared radiation emitted by the Earth’s surface
The three most important greenhouse gases are
carbon dioxide, methane, and nitrous oxide
Why does the Earth have a protective magnetic field?
Because of the motion of electric charges in the liquid outer metallic core
