It is the point where the planet in orbit is furthest from the sun.
The Tropic of Capricorn, sometimes also known as the Southern tropic, is a line of latitude about 23 degrees to the south of the equator. It is one of the five major circles of latitude that mark maps of the Earth. Its equivalent in the northern hemisphere is the Tropic of Cancer.
This is because they are furthest from the direct rays of the sun. Even during the summer when they can receive 24 hours of daylight, the sun is barely above the horizon. Since its rays have to pass through a lot more of the atmosphere, they are "diluted" and can heat the surface very little.
Revolution
in the core
Correct - about 67,000 mph around the Sun.
its not surrounded by thick atmospheres
northern hemisphere
Areas north of the Artic Circle
ellipse
90 degrees
Tropic of Cancer