A pale blue dot is a photograph of Earth taken by the Voyager 1 space probe from a distance of 6 billion kilometers . The image shows the Earth as a speck or point of light almost imperceptible due to the glare of the Sun. The photo was taken on February 14, 1990.
Centuries earlier, however, some philosophers and thinkers suspected that our world was indeed just a tiny speck of dust in an immeasurable universe.
From Locke to Galileo
One of the first to compare the Earth as a mere speck of dust was Pliny in Natural History . Giambattista Capuano da Manfredonia discussed the idea extensively during the 15th century. Also, in 1505 Alexander Achillini affirmed it in, for example, De elementis .
Copernicus insisted that the universe had to be larger than Ptolemy’s .
John Milton (1608-1674) was an English poet and essayist and came to imagine that the Earth was a hanging world, as big as a star.
Blaise Pascal (1623-1662) was a French polymath, mathematician, physicist, Catholic theologian, philosopher and writer who considered the Earth to be an imperceptible point in the vast bosom of nature.
For the philosopher John Locke , the Earth was not a point, but a speck.
Galileo’s telescope made such abstract and theoretical ideas begin to be plausible and perfectly realistic: there could be other inhabited worlds, and space seemed infinite.
As David Wooton explains in his book The Invention of Science :
The idea that the Earth was tiny compared to the universe, or that you could imagine looking at it from afar, was not new; what was new was the expansion of scale that accompanied the new astronomy, so that the Earth could simultaneously be considered a bright star when viewed from another planet and invisible when viewed from deep space, and the influence that this going to see the Earth from an enormous distance had on the imaginations of the cultured people.