Life on Mars - programme summary

Are we alone in the Universe? Or are there aliens somewhere in space? New evidence suggests not only might other life-forms be out there, they may even be living on the planet right next door to us - Mars.

Recent discoveries have shown that Mars has all the ingredients for life, including water. Now the Mars Odyssey probe, launched in April 2001, has detected huge frozen areas of permafrost, just like that found in the Antarctic on Earth.

According to astronomers, the position of this frozen slush could hold the key to Mars' mysterious water cycle. And the surface ice may hide something even more exciting below.

The BBC Space website has plenty more about exploring the Solar System for signs of life:

• past and future missions to Mars
• the hunt for extraterrestrial life
• 3D tour of the Solar System

Read the programme summary, further information or transcript from when Horizon last looked for life on Mars in 2001.