Simplify the following text for a Grade 7 native English-speaking person.
Original: In the solar system , the Earth 's orbital plane is known as the ecliptic plane , and so the Earth 's axial tilt is officially called the obliquity of the ecliptic .
Simplified: It is also called axial inclination or obliquity . The axial tilt of Earth is the cause of seasons like summer and winter on Earth .