Return to 8 Astrophysics – Part A “Units”

8 Astrophysics – Part B “Orbits”

Syllabus Aims…

8.2 know that:

  • the universe is a large collection of billions of galaxies
  • a galaxy is a large collection of billions of stars
  • our solar system is in the Milky Way galaxy.

8.3 understand why gravitational field strength, g, and know that it is different on other planets and the Moon from that on the Earth

8.4 explain that gravitational force:

  • causes moons to orbit planets
  • causes the planets to orbit the Sun
  • causes artificial satellites to orbit the Earth
  • causes comets to orbit the Sun

8.5 describe the differences in the orbits of comets, moons and planets

8.6  use the relationship between orbital speed, orbital radius and time period:

orbital speed = (2 × π × orbital radius)/time period



Use these PowerPoint for a quick review….


Main lesson PPT….

Further Resources….


Useful Videos…

Four Seasons Tilting Planet Model

We have 4 seasons due to the tile of the Earth at 23.5 degrees. Sometimes the Northern hemisphere points towards the sun in the summer and sometimes away in the ...winter.[+] Show More

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