What exists beyond Earth? Over six Lectures presented in 1977, American astronomer and cosmologist Carl Sagan explores the vast expanse of space that surrounds the third planet from the Sun.

Watch all six lectures from this series here:    • The Planets - Carl Sagan's 1977 Chris...  
Watch our newest Christmas lectures here:    • Royal Institution Christmas Lectures  

This lecture was filmed at the Ri on Friday 02 Dec 1977.

---
In his first CHRISTMAS LECTURE, American astronomer and cosmologist Carl Sagan explores planet Earth and the place, scale and geometry of the 'pale blue dot' in the Solar System.

Sagan provides a unique insight into the history of our knowledge of the third planet from the Sun, formed 4.5 billion years ago.

Using images and models of the planets in our Solar System, Carl reveals how the heliocentric model of our universe, in which the Earth and planets revolve around the sun, came to replace the earlier Aristotelian idea that our planet was at the centre and everything orbited around it.

As the complexity of observational tools has developed from simple telescopes to complex spacecraft, so too has our understanding of the world we inhabit. Looking back on the evolution in space science in the years since Carl Sagan's Lectures we have made huge advances in our understanding of our planet’s environment, climate, weather, geology and biology – as well as our relative place in the universe.

---
CARL SAGAN'S 1977 CHRISTMAS LECTURES:

What exists beyond Earth? Over six Lectures presented in 1977, American astronomer and cosmologist Carl Sagan explores the vast expanse of space that surrounds the third planet from the Sun.

Life on Earth
Where at first we could only discern the size of our planet and some knowledge of its atmosphere and configuration, the evolution of planetary exploration has revealed not only intricate details of Earth’s climate and geology, but a multitude of stars and planets besides our own.

Beginning with a closer look at the world we inhabit, Carl explores of the diversity of life on our own planet and the building blocks behind it, before questioning whether the same organic chemistry is occurring on planets in the outer solar system.

The Red Planet
In Lecture three onwards, Carl takes a closer look at our neighbouring planet, Mars. From early interpretations of terrestrial life on its surface to the surprising discoveries made by NASA’s Viking Program, the Red Planet has become the focus of efforts to discern whether intelligent life exists elsewhere in the universe.

When Carl delivered his Lectures in the late 1970s, NASA had only just begun its Voyager program to the furthest planets in our solar system and no extra-solar planets were known to exist. Now, over three decades later, astronomers are looking at planets that lie beyond our solar system to ask the very same question we pondered over Mars: is there life out there?

----
ABOUT THE CHRISTMAS LECTURES:

Set up by Michael Faraday when organised education for children was scarce, the Royal Institution CHRISTMAS LECTURES established an exciting new way of presenting science to young people. World-famous scientists have given the Lectures, including Nobel Prize winners William and Lawrence Bragg, Sir David Attenborough, Carl Sagan and Dame Nancy Rothwell.

First broadcast in 1936, the CHRISTMAS LECTURES is the oldest science television series. They have been broadcast every year since 1966 on the BBC and in later years on Channel Five, Channel Four and more4. In 2010, the Lectures returned to BBC Four, and last year were shown on the 26th, 27th and 28th of December. Find out more about the lectures here: https://www.rigb.org/christmas-lectures
----

The Ri is on Twitter:   / ri_science  
and Facebook:   / royalinstitution  
and TikTok:   / ri_science  
Listen to the Ri podcast: https://podcasters.spotify.com/pod/sh...
Donate to the RI and help us bring you more lectures: https://www.rigb.org/support-us/donat...
Our editorial policy: https://www.rigb.org/editing-ri-talks...
Subscribe for the latest science videos: http://bit.ly/RiNewsletter

Product links on this page may be affiliate links which means it won't cost you any extra but we may earn a small commission if you decide to purchase through the link.