While I am no fan of wildlife programs, there are few people in the media more inspiring than 91-year-old David Attenborough.

Other great contemporary science communicators include Brian Cox, Lawrence Krause, Karl Kruszelnicki, and more recently in Australia, Adam Spencer and Alan Duffy.

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One thing all of these people have in common is a great debt to Carl Sagan, one of the first  -- and possibly the greatest -- science communicator of them all.

 Like Cox, Krause and Duffy, Sagan was also a physicist and cosmologist. Like all of the people who came after him, Sagan really knew his stuff, combining science, philosophy and mathematics to encourage an evidence-based, scientific view of our world.

 Sagan possibly had the greatest voice of them all and an amazing presence. He also had an amazing capacity to put it all in perspective.

More than any science communicator before or after him, Sagan promoted an evidence-based view of science and the importance of evidence as the basis of every decision.

 Carl Sagan, who died in 1996, was a great human being.