Earth in Space

1)  When it is summer in the northern hemisphere,  it is

• winter in the southern hemisphere
• spring in the southern hemisphere
• summer in the southern hemisphere
• fall in the southern hemisphere

What causes Earth's seasons?

• A.  The straight alignment of the Sun, Moon, and Earth
• A.  The tilt of the Earth on its axis as it revolves around the Sun
• A.  Regularly timed solar flares from the sun
• A.  The retrograde motion of Jupiter

 In 11,000 years, the earth’s axis will point to the star Vega instead of the North Star as it does now. The reason for this is:

• precession
• nutation
• barycenter
• elliptical motion

The wobble in Earth's rotation caused by the gravitational pull of the moon is called

• barycenter
• precession
• nutation
• convection

Precession 

• is a change in the angle of earth's axis and effects the seasons
• is the point of balance in the solar system
• causes retrograde motion of planets
• takes 26,000 years and is a change in the direction of Earth's axis

Nutation is

• a change in the direction of Earth's axis and takes 26,000 years
• takes 18 years and is a change in the angle of Earth's axis 
• a point of balance between two objects of different mass
• what we do in English when taking notes

The barycenter

• 18 year wobble of earth's axis
• 26,000 year change in direction of earth's axis
• center of mass of two bodies that are orbiting eachother
• the shape of a planet's orbit

The triangle in this image represents

• nutation
• precession
• elliptical orbits
• the barycenter

_{^{This image shows}}

• barycenter
• precession
• nutation
• elliptical orbits

The red line in this image shows

• nutation
• precession
• barycenter
• elliptical orbits