This imaginary line runs through the North and South Poles.
What is Earth's axis?
This is the main cause of Earth's seasons.
What is the tilt of Earth's axis?
The Moon does not create its own light but reflects this.
What is sunlight?
The central, darkest shadow during an eclipse is called this.
What is the umbra?
All stars begin their life in this cloud of gas and dust.
What is a nebula?
The Sun appears to rise in the east and set in the west due to this motion.
What is Earth's rotation on its axis?
The longest day of the year in the Northern Hemisphere is called this.
What is the Summer Solstice?
The phase of the Moon where none of the lit side is visible from Earth.
What is a New Moon?
A lunar eclipse happens during this Moon phase.
What is a Full Moon?
The Sun is currently in this stage of its life cycle.
What is the main sequence?
If Earth suddenly stopped rotating, one side would experience this while the other side would experience the opposite.
What is constant daylight and constant night?
The hemispheres experience this season when tilted away from the sun.
What is winter?
This is the term for when the illuminated portion of the Moon is increasing.
What is waxing?
This is the reason why we do not experience an eclipse every month.
What is the tilt of the Moon's orbit?
The force that pulls gas and dust together to form a star.
What is gravity?
At the equator, Earth rotates at approximately this many kilometers per hour.
What is 1,600 km per hour?
These two days of the year have nearly equal amounts of daylight and night.
What are the Vernal (Spring) Equinox and Autumnal (Fall) Equinox?
A third quarter Moon is also called this.
What is a last quarter Moon?
These three types of solar eclipses exist.
What are total, partial, and annular eclipses?
A dying low- or medium-mass star forms this structure before becoming a white dwarf.
What is a planetary nebula?
We do not feel Earth's spinning motion due to these 3 properties.
1. Inertia
2. Size of Earth
3. Pull of gravity
If Earth's tilt increased to 45°, this would happen to the seasons.
What is more extreme seasonal differences (temperature and light)?
The Moon appears to change shape due to this motion.
What is the Moon’s revolution around Earth?
This explains why the Moon appears red during a lunar eclipse.
What is Earth's atmosphere scattering blue light (shorter wavelengths) and allowing red light (longer wavelengths) to reach the Moon?
A high-mass star may collapse into one of these after a supernova.
What is a black hole or neutron star?