Did Herschel see Uranus’ rings?

It’s a mystery that has baffled astronomers for many years

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This image, taken using the Keck Telescopes, displays Uranus' rings. However, could Herschel have observed them as early as 1797?

This image, taken using the Keck Telescopes, displays Uranus’ rings. However, could Herschel have observed them as early as 1797?

Turning his homemade telescope to the heavens in 1781, brilliant astronomer William Herschel uncovered the seventh world from the Sun, Uranus. Originally, he thought that he’d found a comet and reported it as such over a month later. However, suspicions that Herschel’s finding was indeed a planet, came thick and fast from astronomers as far out as Russia. Herschel had indeed found Uranus.

That doesn’t seem too much of a mystery. Not until we consider that we came across Herschel’s records which implied that he had witnessed the ice giant’s ring system in 1797. This should have been impossible – the rings are far too faint to be seen by amateur telescopes from Earth. It was not until 1977 that the rings of Uranus were officially discovered during an occultation – that is, when Uranus moved in front of a star from our point of view, Uranus blocked the starlight, but the scientists actually found that the star disappeared from view not once, but five times, pointing heavily to  two rings around Uranus (subsequent observations have shown Uranus has 13 dark, faint rings).

How could Herschel have seen the rings 200 years before, given that his telescope certainly was not powerful enough to see them as they are now? Had something caused them to brighten at that time, or was Herschel’s observation in error and just a coincidence? Whether Herschel really saw the rings or not is a mystery of history.

Image Credit: NASA  

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