The universe is a bewildering place, but Carl Sagan had an amazing ability to understand and describe the wonders of the universe, from empty space to the origins of intelligent life. Sagan is best known for his ground-breaking documentary "Cosmos" and his popular science books, including "A Pale Blue Dot" and "The Dragons of Eden". As well as his celebrity side, he was also a highly acclaimed planetary scientist and Professor of Astronomy and Space Sciences at Cornell University in the USA.

One of his interests was in investigating the possibility of extra-terrestrial life. His studies into the environment of other planets within our solar system led to discoveries that they were much harsher places than originally thought. His search didn't end there, and he was a very vocal supporter of the Search for Extra-Terrestrial Intelligence (SETI) which uses radio telescopes to listen out for signs of life.

But perhaps his longest-lasting legacy will be his work on the Golden Records placed on the Voyager spacecraft. These records contain a range of images and sounds from Earth and have been sent out, along with instructions on how to play them, for other intelligent life to find and discover something about life here on Earth. Two Voyager probes were launched in 1977 to study the planetary systems of Jupiter, Saturn, Uranus and Neptune in unprecedented detail. Their mission has been extended three times and they continue to transmit useful scientific data. In 2012, Voyager 1 become the first human-made object to enter interstellar space.

Want to learn more?

The physics of particle and planetary motion are a core part of all physics degree programmes at Heriot-Watt and are investigated in detail in the 3rd year course B29DR Dynamics and Relativity. The science behind satellite technology and how it can be used to investigate planetary surfaces is explored in the 4th year course B20OE Remote Sensing and Energy Studies.