1. Black hole – A black hole’s gravitational pull is so strong that even light can’t escape from what’s known as its ‘event horizon’, an invisible boundary around it.
  2. Mighty moon The moon’s low gravity means objects weigh one sixth of their Earth weight. A strong man could lift a small car on the moon!
  3. Escape velocity Deimos, a moon of Mars, has such low gravity that if you jumped, you’d easily achieve escape velocity and send yourself into space.
  4. Gravity and fitness Prolonged exposure to zero gravity poses health risk for astronauts, including bone loss, muscle atrophy and even immune problems.
  5. Pulling power Size and mass effect gravity: Uranus has 14.5 times the mass of Earth but because of its size, it only has around 90 per cent of Earth’s gravity.