Issue 41: not Venusian surface features, but retinal veins
In an effort to see beyond our world, an astronomer inadvertently turned the lens on himself.
The Lowell Observatory in Flagstaff, Arizona, founded in 1894, is an important site of astronomical research and discovery.
Its staff and equipment have been responsible for detecting the expansion of the universe, mapping the moon for the Apollo programme, and discovering Pluto and the rings of Uranus.
But its founder and namesake's astronomical record was not always so stellar.
Percival Lowell was born in 1855 to a wealthy Massachusetts family that made its money in textiles (the town of Lowell, Massachusetts is named after them). He graduated from Harvard University with a degree in mathematics, worked in the family business for a time, and devoted himself to literature and travel.
Then, in the 1890s, inspired by Italian astronomer Giovanni Schiaparelli’s work mapping Mars – and an alleged mistranslation of Schiaparelli’s observation of its channels (or “canali”) – Lowell created a private observatory to search for extra-terrestrial life.
You see, Lowell interpreted ‘canali’ as ‘canals’ – an artificially created waterway – and took it as a sign of intelligent life on the red planet. He hired telescope makers Alvan Clark & Sons to build a 24-inch refractor, and went on to map hundreds of Martian-made canals and oases on Mars, and publish books on the subject.
Of course, contemporary technology has proved Lowell’s work to be incorrect. But even in his own time, fellow astronomers could not replicate his observations and vigorously opposed his proclamations. (Although, it must be noted that the public was enthralled by his supposed evidence of alien life.)
Lowell was likely experiencing an optical illusion created by our brains’ tendency to see patterns were none exist. (Mars is home to another example of this, even more famous than Lowell’s work.)
Undeterred, Lowell set his sights on Venus, too.
Despite it being Earth’s closest planetary neighbour, and one of the brightest objects in the night sky, its surface is obscured by a thick, cloudy atmosphere.
To improve visibility and reduce the effects of atmospheric turbulence, Lowell reduced the aperture of his telescope to as little as 1.6 to 3inches.
He could now see streaks on the planet’s surface, which he depicted as spidery lines radiating from a single hub.
As with his observations of Mars, other astronomers – including his own assistants – did not see what Lowell did. Except for his secretary. Lowell took this as a positive sign. If a novice (or “blank slate”, as he described her) could see it, it must be real. He reasoned it was the preconceived ideas and prejudices of his learned colleagues that was preventing them from accepting the vision.
In an 1896 article in ‘Astronomische Nachrichten’, Lowell described the markings he saw on Venus as:
“…surprisingly distinct; in the matter of contrast, as accentuated in good seeing as the markings of the Moon, and owing to their character much easier to draw; in the matter of contour, perfectly defined throughout, their edges being well marked and their surfaces well differentiated in tone from one another, some being much darker than others.”
He wrote in ‘Popular Astronomy’ in 1904 that they appeared “with a definiteness to convince the beholder of an objectiveness beyond the possibility of an illusion”.
Lowell dismissed the obvious issue that the hub from which the streaks emerged was always in the same location, regardless of the planet’s changing phases. He credited this phenomenon to the superior location and conditions – the “see level” – of his observatory.
It’s this part of Lowell’s story that I find most fascinating. Because this time, what the astronomer was seeing was really there, it’s just not what he thought it was.
You see, what experts have concluded, is that by so drastically reducing the aperture of his telescope, Lowell had effectively converted it into an ophthalmoscope. That’s the instrument your optometrist uses to check the health of your eye. It shines a narrow beam of light through the pupil, illuminating the network of vessels that supply blood to the retina. The patient is often able to see glimpses of their own blood vessels, especially when the light is in motion.
In his sketches of Venus, Lowell was accurately recording what he saw, but what he saw was the transference of his retinal blood vessels onto the surface of our neighbouring planet.
The final tale from Lowell’s career that I will leave you with is – again – a misobservance, but it did conclude in a successful discovery after his death.
Lowell had calculated variations in the orbit of Uranus, which convinced him there must be a ninth planet in our solar system. Similar changes in Uranus’ orbit had led to the discovery of Neptune in 1846 (the first predicted by mathematics before its discovery).
Lowell’s speculations indicated that the mystery “Planet X” must be at least the size of Earth. He took pictures of the sky at different times, and from around 1905, multiple observers pored over the images searching for movement that would indicate a new planet.
In 1916, with no discovery yet made, Lowell died. He left behind a legacy to fund the continued search for the planet.
14 years on, while working at the Flagstaff observatory, Clyde Tombaugh discovered Pluto in the region Lowell had indicated. However, it was much smaller than predicated – too small to have affected the orbit of Uranus, as Lowell had calculated. (In 2006, Pluto it was downgraded to a dwarf planet.)
Despite the wax and wane of his astronomical reputation, Lowell’s wonder and awe of space lives on. The observatory he founded welcomes more than 100,000 visitors every year and is designated as a Registered National Historic Landmark.