* The Prime Meridian: This is the starting point for measuring longitude, designated as 0 degrees.

* The International Date Line: This line is approximately 180 degrees of longitude away from the Prime Meridian. It's the point where the date changes.

* A "og longitude" is likely a typo and should be "180th longitude." The 180th meridian is the meridian that aligns with the International Date Line.

Therefore, there are 180 degrees of longitude between the Prime Meridian and the International Date Line.