Bones, cardiovascular systems, muscle tissue and organs all change in zero-g, and the longer an astronaut stays aloft, the more marked the changes that take place.

The aurora borealis ("Northern Lights") is caused by the Earth’s magnetic field and its interaction with ionized particles.

The Black Box flight recorder was first invented in 1958 at the Aeronautical Research Laboratories, Melbourne, Australia. It is an orange colour.

The antlers of a moose are created from living tissue supplied by blood through a network of vessels covered with a soft smooth skin called velvet. Eventually the tissue becomes solidified, the velvet is scraped off, and the antlers become completely formed of dead matter.

In the 1970s, Peter Sturrock sent questionnaires to 2,611 members of the American Astronomical Society. Replies were received from 79 percent of the members (2062). Of these 62 respondents had either personally observed a UFO or had detailed knowledge of a sighting.

The smallest dinosaurs were just slightly larger than a chicken. Compsognathus is one of the smallest and was about 1 m (3 feet) long and weighed about 2.5 kg.

Skydivers reach a terminal velocity of about 120 miles per hour (190 km/hr) if they spread eagle themselves to maximise their air resistance, but a velocity of 150 mph (240 km/hr) if they assume a head-down position like a high-board diver about to enter the water.

The song, 'I am the Walrus', by John Lennon was inspired by a police two-tone siren.

There are stars as much as 400,000 brighter than the sun and others as much as 400,000 time fainter if they could all be seen at the same distance.