Robert began his talk by suggesting that the Blue Marble, "seems to sum up every kind of understanding of the whole earth, with its sense of wholeness, healthiness, depth, inclusiveness, alternative technology ... it sums up that really rather strange world of the early 1970s." He then provided a brief history of Earth visualisation (pre Blue Marble), noting the extent to which geographic globes were established in the cultural imaginary long before astronauts went into space. Photograph credit: NASA.

3 mins: Francisco de Holanda, The Creation of the Sun and Moon (1547). The earliest image, "by centuries that shows the Earth as blue and white." In many ways a prophetic work. Image credit: National Library of Spain. Click thumbnail above to visit the library's website for a collection of de Holanda's works

4mins 20 secs: Image by space artist Howard Russell Butler (1920). An early example of the kinds of Earth imagery with which we are now familiar. Robert notes that the idea of "black space" is relatively recent, with the belief until almost the twentieth century being that we only went dark when we were in the sun's shadow.

4mins 50 secs: US Weather Bureau satellite simulation of a Whole Earth image from 1954. Credit: US Weather Bureau.

5 mins 30 secs: Image by Chesley Bonestell for Colliers magazine (1952). One of a sseveral illustrations created by Bonestell for a series of articles entitled "Man Will Conquer Space Soon." Credit: Colliers (March 25, 1952).

6mins 15 secs: NASA's Lunar Orbital Plan for Apollo 8 (1968). Robert noted that there was little difference in terms of how the Earth and Moon was represented, with no sense of the Earth as a living planet and the Moon. Credit: NASA.

6mins 55 secs: The first "Whole Earth" photograph, taken by the Explorer Satellite in 1959. The image was subjected to a great deal of processing before release. NASA noted in its description that "scientists can discern clouds in the large white areas." Credit: NASA.

7mins 35 secs: The first colour Whole Earth photograph, taken by the ATS-III satellite from 21,000 miles out in 1967. The Washington Post went into colour in order to publish the photograph, and it appeared in National Geographic. This was also the image that famously appeared on the front cover of the Whole Earth Catalog (1968, see next image). Credit: NASA.

10mins 15 secs: The Whole Earth Catalog (Fall 1968). The Catalog's creator, Stuart Brand, had campaigned for NASA to take a Whole Earth photograph and his story plays a part in Blue Marble mythology (see Neil Maher's talk below).

10mins 45 secs: Photograph from Apollo 4 (1967), an un-crewed mission. This photograph was hardly publicised and has not received much attention. Robert described the photograph as capturing the Earth "asleep" and noted its "3D appeal." It was placed on the front cover of a later Whole Earth Catalog. Credit: NASA.

11mins 30 secs: Apollo 8's Earthrise photograph (1968). The photograph is usually reprinted in landscape format, offering a familiar, appealing representation of the Earth rising over the moon. However, as Robert noted, the photograph was originally captured with the Earth to the side, portrait style as the astronauts were orbiting equatorially. Credit: NASA.

12mins 50 secs: A digitally remastered Earthrise, as will appear on the front cover of the new edition of Robert's book on the photograph.

14 mins: Photograph taken by Apollo 8 astronauts on their way home. This photograph appeared on the "Whole Earth Flag" of 1969 (listen to Robert's talk for more information). Credit: NASA.

14 mins 45 secs: The Soviet satellite Zond 7 satellite photograph of the Earth (1969). Robert noted that "no Soviet Cosmonaut ever saw the Whole Earth", but satellites did capture some vivid representations.

15mins: a Blue Marble-like image taken by Zond 7 (1969).

15 mins 40 secs: The original Blue Marble (1972). Here, Robert provides some historical background to NASA's photographic ambitions and the key people involved - from NASA employees to editors at National Geographic magazine - in ensuring Apollo 17 astronauts captured a range of Earth images. Unlike Earthrise, the Blue Marble photograph was planned.

21 mins 20 secs: undated Friends of the Earth poster using the Blue Marble photograph. An early example of the photograph's use in environmental campaign materials.

27mins 10 secs: Poster commissioned by the National Academy of Sciences (1957). Robert provides, from here, background to scientific thought of the post-war era, and its connections to space photography. Image credit National Academy of Sciences.

31 mins 30 secs: Diagram from the Scientific American (September 1970).

32 mins 30 secs: book cover, Only One Earth (1972), an unofficial report commissioned by the Secretary General of the United Nations in the wake of the 1972 "first Earth summit."

33 mins 30 secs: In the early 1970s, the American physician Lewis Thomas wrote an essay entitled "The World's Biggest Membrane," where he compared the Earth to a living cell (not dissimilar to the Gaia theory then being developed by James Lovelock) and contemplates images of Earth from space. Image credit: NASA.

Thomas continued.

35mins: Other "Blue Marbles" - an image of Venus taken from Mariner 10 in 1974.

35mins 40 secs: James Lovelock began developing his Gaia theory in the mid 1960s. The first articles, written with Lynn Margulis, appeared in the early 1970s.

38mins 20 secs: The image of the Whole Earth as a summation of much scientific and environmental thinking of the period. Credit: NASA.

44mins: A recent "Blue Marble" captured by the DSCOVR satellite, December 5, 2022. Credit: NASA.

44mins 45 secs: Comparison of the 1972 Blue Marble and the photograph taken on December 5, 2022. Robert concluded his talk by reflecting on the changes to the Earth's climate that these photographs might reveal and argued that "the only mission that matters anymore is what NASA called in the 1990s the mission to Planet Earth."