- Earth is estimated to weigh 6,585,600,000,000,000,000,000 tons! That is why its gravity is so strong.
- Jupiter’s moon, which is called Io, is so light and therefore has such low gravity that its volcanoes can send boiling rock 80 kilometres into the air!
- Our sun is just one of over 100 billion stars which make up our galaxy which is called the Milky Way; and there are millions of galaxies in the Universe!
- Summer on the planet Uranus lasts for 21 years, and so does winter!
- It would take a car travelling at 160 kilometres per hour nearly 30 million years to reach our nearest neighbouring star.
- The Skylab astronauts grew 3.8 – 5.7 centimetres (1.5 – 2.25 inches) due to spinal lengthening as a result of zero gravity. They shrank back to normal size when they got back to Earth.
- Gravity is so strong that Apollo astronauts had to reach a speed of 25,000 miles (40,000 kilometres) per hour to leave the Earth and journey to the Moon; otherwise they would have been pulled back to Earth by gravity.
- The US Space Agency NASA has a satellite called GRACE, which has calculated that Greenland is losing 100 billion tonnes of ice a year through global warming. It calculates this by the small change in the pull of gravity (the greater the mass of ice, the greater the pull of gravity) over Greenland