Chapter 6 Flashcards
At what speed does the earth move around the sun
Almost 20 miles per second
What causes the earths shape
Gravity, and it’s spin which makes its equator bulge
What are the most common elements found in earths surface
Oxygen,silicon,aluminum,iron,calcium, and magnesium
What is density, and what is the density of the earth
Density is how much mass is peaked in a given volume, earths density is around 5.5 g/cm3
What are earthquakes
They are seismic waves that move through the earth
How do we probe the earths/other planets interior
We use a sonogram to detect seismic waves and their speeds/properties to determine things such as density and materials
What are the two types of seismic waves
P waves and S waves
What are P waves
P waves compress material and easily travel through solid and liquid
What are S waves
S waves only travel through solids
How do we know earths core is a liquid?
We only detect P waves but no S waves when on the other side of the earth from the origin of the seismic waves
What are the layers of the earth
Crust,mantle,liquid core, solid core
What is the crust
It is a thin low density layer mainly made of silicates
What is the mantle
It is hot, thick, not quite liquid silicates
What is the liquid core
It is a liquid mixture of iron,nickel, and sulfur
What is the solid core
It is a hot solid mixture of iron and nickel
What is differentiation
The fact that the earths layers go from densest at the center to least dense at the surface
What is the estimated temperature of the earths core
6500 K
How do we determine the age of the earth
Radioactive decay
What is the shifting of large blocks of the earth called
Plate tectonics
What protects the earth from outer space radiation
It’s magnetic field
What is polarity
The connection between north magnetic poles and south magnetic poles
What generates the earths magnetic field
Currents flowing in its molten iron core
What is the magnetosphere
The magnetic region that affects particle motion and protects the earth
Do charged particles get trapped in the magnetosphere
Yes, in a region called the van Allen radiation belts
What causes an aurora
Charged solar particles streaming past the magnetic field
What is the composition of the earths atmosphere
78.08% nitrogen and 20.95% oxygen
What is the greenhouse effect
It is infrared energy radiating from the earth due to the heat let in by the atmosphere that gets trapped and cannot escape back into space
What part of the atmosphere shields from solar UV radiation the most
The ozone layer
What is the changing in direction of earths spin axis called
Precession
