What is an Axis?

What is an "axis" according to the video?

A wheel on a car spins around an...

The Earth is slightly tilted and spins on it's axis at about

Uranus spins on its axis at about 98^o, what does this mean?

Why did our North Star, the star our Earth's axis points to, change?

How did Hipparchus find that our planets axis is changing?

The Earth is 26 miles..

Acceleration works against gravity greater at the equator than the poles... what does it do to the Earth..

The Earth's axis spins because of the sun and completes one revolution every

How long is a tropical year?

What is the difference?

Why is a sidereal year different than a tropical year?

The Gregorian calender was not adopted in Russia until

What would be the consequence of sticking with a sidereal calendar based on star positions rather than the tropical calendar which was based on the seasons?

What are the problems with sticking with a tropical method of dating the length of a year?