It is measured exactly the same in the Southern Hemisphere (no difference between the two hemispheres).
It is the difference between magnetic north and true north and it varies all over the globe.
Magnetic declination (also called magnetic variation) is positive when magnetic north is east of true north (clockwise) and it is negative when magnetic north is west of true north (anti-clockwise).
The four hemispheres are called the Northern Hemisphere, Southern Hemisphere, Eastern Hemisphere, and Westhern Hemisphere.
The Equator divides the southern and northern hemisphere.
The world is divided into 4 quarters - western hemisphere, eastern hemisphere, northern hemisphere, and southern hemisphere.
A hemisphere is exactly 1/2 of the earth. We speak of the Western Hemisphere, the Eastern Hemisphere. the Southern Hemisphere, and the Northern Hemisphere.
the hemisphere divides the earth into four different chunks
Inclination is measured as the angle at which the satellite crosses the equator while passing from the southern hemisphere to the northern hemisphere. Declination is the difference between magnetic North as reported by a compass and true North.
The Summer Solstice in the northern hemisphere, where the sun is highest declination.
Quite arbitrarily. But in the northern hemisphere, the shadow of a sundial will traverse clockwise. And this is probably the origin of the term and the common usage. [My speculation.]
in northern Canada
Magnetic variation (also known as magnetic declination) is often indicated on maps. But if the magnetic variation of a location is unknown, a declinometer can be used. Basically, this tool determines the angle between the celestial pole (roughly indicated by the North Star in the northern hemisphere) and the magnetic pole (indicated by a compass).
Who told you that ? There is no "why", because you certainly can. From the northern hemisphere, you can see stars with declinations down to (your latitude) minus (90°).
The Summer Solstice in the northern hemisphere, where the sun is highest declination.
From the perspective of the Northern Hemisphere, this solstice will be called the "winter" solstice.
No, the moon is only up for approximately half of the day depending on it's declination in it's orbit. When the moon is at it's most northerly declination, the moon will be above the horizon for a much longer period of time when viewed from the Northern Hemisphere, and will be in the Northern Hemisphere sky for a much shorter period of time when the moon is at it's most southern declination - at the same time however, the moon will be in the Southern Hemisphere's sky for much longer.
The north pole.
The northern hemisphere.
There is- it is called the Magnetic North Pole. The magnetic one is constantly shifting around the Northern Hemisphere and in a year will move 15km.